490 Final Report COMPLETE With PDFs

T e a m U l t r a L u x P a g e | 1

LumaKing 550LED Product Description, Hardware Block Diagram and Software Flow Charts

Cover Sheet

Team: UltraLux

Team: Members Adam Morris Ivan Nguyen Thanh Nhut Tran (Andy) Loc Hinh


Table of Contents Cover Sheet ................................................................................................................................................... 1

Team: ............................................................................................................................................................ 1

Team: Members ............................................................................................................................................ 1

Team Members ............................................................................................................................................. 6

Adam Morris ............................................................................................................................................. 6

Thanh Nhut Tran (Andy) ........................................................................................................................... 6

Loc Hinh .................................................................................................................................................... 7

Ivan Nguyen .............................................................................................................................................. 7

Introduction .................................................................................................................................................. 8

Project Overview ........................................................................................................................................... 9

Existing Products ......................................................................................................................................... 10

Dracast LED1000 Pro Bi-Color LED Light ................................................................................................. 10

CineLED EVO "S" - 5600K ........................................................................................................................ 10

CineLED EVO "XL" - 5600K ...................................................................................................................... 10

Genaray SpectroLED Outfit 500 Bi-Color LED Light ................................................................................ 11

Genaray SpectroLED Studio 1000 Bi-Color LED Light .............................................................................. 11

CineLED 1x1 DMX - 5600K ....................................................................................................................... 11

Product Comparison Table ..................................................................................................................... 12

Product: ............................................................................................................................................... 12

LumaKing 550LED $999.99ea .................................................................................................................. 12

Features: ............................................................................................................................................. 12

Power / Voltage: ................................................................................................................................. 12

Light Intensity: .................................................................................................................................... 12

CRI: ...................................................................................................................................................... 12

Color Temp Range: .............................................................................................................................. 12

LED Beam angle:.................................................................................................................................. 12

Casing: ................................................................................................................................................. 12

Dimensions (cm): ................................................................................................................................ 12

Weight (kg): ......................................................................................................................................... 13

Product Comparison Table ...................................................................................................................... 13

Product: ............................................................................................................................................... 13


Genaray SpectroLED Studio 1000 Bi-Color LED Light $938.95 ............................................................ 13

CineLED 1x1 DMX - 5600K $681.12............................................................................................................. 13

Features: ............................................................................................................................................. 13

Power .................................................................................................................................................. 13

Light Intensity: .................................................................................................................................... 13

CRI: ...................................................................................................................................................... 13

Color Temp Range: .............................................................................................................................. 13

LED Beam angle:.................................................................................................................................. 13

Casing: ................................................................................................................................................. 13

Dimensions (cm): ................................................................................................................................ 13

Weight (kg): ......................................................................................................................................... 13

Project Objectives ....................................................................................................................................... 14

Software Verification: ............................................................................................................................. 14

Firmware Verification: ............................................................................................................................ 14

Hardware Verification: ............................................................................................................................ 14

Specifications .............................................................................................................................................. 15

Physical Specifications ............................................................................................................................ 15

Features: ............................................................................................................................................. 15

Power/Voltage .................................................................................................................................... 15

Light Intensity ...................................................................................................................................... 15

Color Temperature: ............................................................................................................................. 15

LED Beam angle:.................................................................................................................................. 15

Temperature ....................................................................................................................................... 15

Wireless ............................................................................................................................................... 15

Weight ................................................................................................................................................. 15

Size ...................................................................................................................................................... 15

Build Materials .................................................................................................................................... 15

Manual Control Switch ........................................................................................................................ 15

Physical Specifications ............................................................................................................................ 16

Dimmer Dial ........................................................................................................................................ 16

On/Off Switch...................................................................................................................................... 16

LED Status Indicator ............................................................................................................................ 16


Operating Environment ...................................................................................................................... 16

User Interface ............................................................................................................................................. 17

Theory ......................................................................................................................................................... 18

Hardware ................................................................................................................................................ 18

Firmware: ................................................................................................................................................ 18

Software: ................................................................................................................................................. 18

Hardware Design ......................................................................................................................................... 19

The Control Module: ........................................................................................................................... 19

The Signal Buffer: ................................................................................................................................ 19

The Dimmer Module: .......................................................................................................................... 19

The Xbee Module: ............................................................................................................................... 19

Block Diagram ............................................................................................................................................. 20

Schematic .................................................................................................................................................... 21

Hardware Task List ...................................................................................................................................... 25

Hardware Development .......................................................................................................................... 25

Firmware Design ......................................................................................................................................... 26

Firmware Flowchart .................................................................................................................................... 27

Initialize Hardware Flowchart ................................................................................................................. 27

Initialize Peripheral Flowchart ................................................................................................................ 27

Main Loop Flowchart .............................................................................................................................. 28

Firmware Task List ...................................................................................................................................... 29

Firmware Development .......................................................................................................................... 29

Software Design .......................................................................................................................................... 30

Software Flowchart ..................................................................................................................................... 32

Software Task List ....................................................................................................................................... 33

Software Development ........................................................................................................................... 33

GANTT Diagram ........................................................................................................................................... 34

Costs ............................................................................................................................................................ 35

Conclusions ................................................................................................................................................. 36

Hardware Conclusion: ............................................................................................................................. 36

The Good: ............................................................................................................................................ 36

The Bad: .............................................................................................................................................. 36


Software Conclusion: .............................................................................................................................. 36

The Good: ............................................................................................................................................ 36

The Bad: .............................................................................................................................................. 37

Firmware Conclusion: ............................................................................................................................. 37

The Good: ................................................................................................................................................ 37

The Bad: .................................................................................................................................................. 37

Appendix A .................................................................................................................................................. 38

Appendix B ..................................................................................................... Error! Bookmark not defined.

Firmware Reference ................................................................................... Error! Bookmark not defined.


Team Members Adam Morris My name is Adam Morris. I’m from a small town in Washington State called Hoquiam. My background is varied. I have worked as a photojournalist, served as an Infantryman in the U.S. Army, shot pictures as an advertising and fashion photographer, developed methods for a National Guard Division to share data in a war fighting scenario, and managed a startup as a project manager. I am now working towards a degree in Computer Engineering with a minor in Computer Science. Project Lead: Adam is the Project Lead for the LumaKing LED light panel project. The Project Lead is overall responsible for the time frame and organization of this project. Adam keeps track of report submission and project completion status.

Thanh Nhut Tran (Andy) My name is Thanh Nhut Tran, however I go by Andy. I am an immigrant from Viet Nam and soon I will be a naturalized U.S citizen. I was born in Kien Giang, Viet Nam and lived there for 16 years. My family moved to the United States to seek a better life. I am one of the first generation of my family to go to college. I am now 22 years old. I’m working toward my bachelor’s degree in computer engineering. Hardware Lead: Andy Tran is the Hardware Lead designer is responsible for the design and utilization of all electrical components. These components include, the High and Low power Printed Circuit Boards, led array, heat sink and any other physical element


Loc Hinh My name is Loc Tri Hinh. I was born in Garden Grove, California in 1991. My family had wishes of me becoming a medical doctor, but I found my interest towards technology. I was introduced to my first computer at the age of four, which came with trial software of America Online (AOL) 3.0. Over the course of several years, I’ve grown an interest in computers and began to pursue this curiosity. During my early college years, I was torn between majoring in Physics or Computer Science. I changed my major to Computer Engineering after transferring into California State University Long Beach after being exposed to its classes. I knew instantly that I preferred engineering over programming. Software Lead: Loc Hinh The Software Lead designer is responsible for the mobile application code base. He will oversee the development of the mobile application to include a user friendly interface, openCV integration and appropriate use of mobile communication APIs

Ivan Nguyen My name is Ivan Nguyen. I was born in Garden Grove, but raised in Santa Ana, California. I was born into a clash of cultures: I am half-Vietnamese and half-Mexican. As such, I always perceived the world in a different light compared to others. I grew up always wondering how things worked, and more importantly, its purpose. I’ve always needed to feel challenged in order for me to be motivated. As a result, my father became my catalyst for delving into the sciences. Being an electrical engineer himself, he casted quite a shadow on my life. He awoke my competitive nature, and since then it has taken over to all facets of my life. Engineering is only the beginning… Firmware Lead: Ivan is the Firmware Lead designer is responsible for design and implementation of the microcontroller code base. He will develop dimming algorithms, on board chip communications and wireless library implementation. .


Introduction

The LumaKing 550LED lighting system provides amazing studio lighting and impromptu studio control without the infrastructure. Each 550LED light shines at an incredibly bright 9411 lux at a distance of 10 feet. These exceptional lights connect together wirelessly to reduce setup time, and provide for a cleaner and safer set area. The base 550LED system includes a pair of film and television rated, wirelessly controlled, studio LED lights. The lights work in interior lighting situations, with a power rating of 550 watts each. The two identically bright LED panels are situated in a master and slave relationship. One acts as the slave and the other as the master. Both lights will interact wirelessly with a mobile device such as a cell phone or tablet computer. The 550LED comes with an Android application allowing for wireless Light Board like control from an Android phone or tablet. The Android controller application offers sliders for lighting control plus uses computer vision to identify a human form and analyze the highlight and shadow detail. The application will then allow for auto adjustment of the lighting to standardized lighting patterns: 1:1, 1:2, 1:8, and so on.


Project Overview Theatrical lighting has developed for thousands of years. Originally, Greek theaters were built facing west in order to take advantage of the afternoon sun. The next advancement was interior lighting by chandelier. Then in 1820 Goldsworthy Gurney discovered chemical limelight. With the advent of electricity, tungsten lights filled the stage with light. Now the industry is moving towards LED lighting. LED lighting is more power efficient than tungsten lighting. It’s also more durable than the fine filaments of the tungsten bulb. Lighting control has developed over the years as well. Normal operations for theater or film production occur with hundreds of feet of wires attaching each light to a DMX Digital Multiplex enabled light. These DMX lights are controlled through a light control board at a central location. Barring the control that DMX provides, some lights must be individually manned. These situations require multiple people with great skill to operate the various lights of the set or scene. The Lumaking project is designed around this light board concept. The exception with the LumaKing is it strives to replace the countless control wires of DMX boards or the even more inefficient setup of a single human operating a single light. LumaKing will communicate with its lighting system siblings through a wireless connection. The light board is replaced by a virtual one in the form of an Android application. Setup time is greatly improved by the reduction of wires down to a simple power cord for each LumaKing light. The Lumaking project is designed around multiple technologies: Xbee and Wi-Fi wireless communications, Android, and LEDs. A main light acts as a hub for all communications between the light controls on the Android app. Xbee wireless signals transfer data from one light to the next in a mesh network. Wi-Fi allows the main light to communicate with the Android application. LEDs allow for a more favorable light output to power draw ratio. LumaKing gives the lighting professionals control and easy light setup installation. There are multiple times when a still or movie shoot is performed ‘on location’. This on location shoot still requires lighting and setup, usually in a confined space. LumaKing lights reduce the setup time by not adding control wires between the lights. The lights will wirelessly connect with the main light, then their information will be displayed on a wireless application. LumaKing gives automatic controls for fast and accurate, professional results. The LumaKing project includes the use of computer vision from the Android application. The application will detect a human form, then allow the user to adjust the lights automatically by selecting preset lighting ratio levels. These light levels drastically reduce the time needed in lighting set up, saving the production time and effort. The Lumaking will cost a reasonable rate of $1000 per light. Lights with less control and less light output cost more and we feel this is a good price point for the intended market.

T e a m U l t r a L u x P a g e | 1 0

Existing Products

Dracast LED1000 Pro Bi-Color LED Light The Dracast LED1000 Pro Bi-Color panel features a medium range light output with controls for adjusting color temperature and dimming with little to no flicker. The color adjust feature quickly matches the ambient light without the use of additional filters. The LED1000 has an anodized aluminum case which allows the fixture to be lightweight and sturdy. Its CRI rating is at 95, which is outstanding for any panel. Power consumption is also low at 60 W. Light intensity differs depending on the color temperature: at 4400K, it outputs 7200 lux at 0.9 meters and that number drops to 3800 lux at 3200k for the same distance. There are also 4-way barn doors which allow it to contour the 45 degree beam angle.

CineLED EVO "S" - 5600K The CineLED EVO “XL” is as it names suggests, a larger LED panel measuring at 31” wide rather than the traditional 12’’. The aluminum housing is designed to dissipate the heat faster. The heat dissipation increases the LED's life and maintains a cool-to-touch surface temperature. This LED panel is also recommended for chroma-key (blue/green screen) applications, easily acting as a key light for the setup or fills light for the chroma background. It also features dimming control from 100% to 0% and a digital display on the back of the panel that shows the brightness value so that multiple similar LED fixtures can be matched in the same setup. The EVO XL also has a high CRI rating of 95 and a light beam angle of 45 degrees. Its power is significantly higher however at 120 W. Its color temperature is at a constant 5600K with a light intensity of 12,000 lux at 1 meter.

CineLED EVO "XL" - 5600K The CineLED EVO “S” has very identical specifications to the EVO XL except on a smaller scale. It still features the same aluminum housing designed to dissipate heat more rapidly, dimming control, constant color temperature of 5600 K, 45 degree beam angle and a high CRI rating of 95. However, its power consumption is much lower at 38 W meaning its light intensity suffers by dropping to 4800 lux at 1 meter.


Genaray SpectroLED Outfit 500 Bi-Color LED Light The Genaray SpectroLED Outfit 500 comes with 508 LEDs with variable color temperature from 3200K to 5600K. It also has dimming from 100% to 0% and a larger beam angle at 60 degrees. It includes a diffusion filter which helps soften the output light. The power rating is a moderate 60W. It has a lower CRI rating of 85 and its light intensity is 2,550 lux @ 1 meter.

Genaray SpectroLED Studio 1000 Bi-Color LED Light The SpectroLED Studio 1000 features a large LCD touchscreen for adjusting color temperature from 3,200K-5,600K so that you can quickly match other light sources. Dimming the light intensity from 100-10% with negligible color shift is enabled by your adjustments on the back panel or wirelessly via the included wireless remote control. It also features a 60 degree beam angle. The CRI rating for this panel is 93 with a power rating of 60W. The light intensity is 6600 lux at 1 meter.

CineLED 1x1 DMX - 5600K The CineLED DMX 1x1 Panel has 1296 LED’s that produce luminous, directional lighting, at a beam angle of 45 degree. Its power drawn is only 78W while providing a light intensity of 10100 lux at 1 meter. The CRI rating for this panel is 95. The output is dimmable from 100% to 0%, maintaining a constant color temperature across the entire dimming range. The light intensity adjustments are made through a steeples sliding dimmer that provides a smooth control over the light beam. This model of CineLED Panel 1x1 5600K features a DMX-512 controller, enabling remote operation of the unit from any DMX console, letting you control the light output in small increments or create custom programs for light intensity for various scenarios in a studio. This model is equipped with two DMX port (in / out – loop) with Ethernet RJ-45 receiver connectors. The manual DMX address supports 16 individual channels.

http://www.bhphotovideo.com/c/product/979324-REG/genaray_sp_s_1000b_spectroled_studio_1000_bi_color.html


Product Comparison Table

Product: LumaKing 550LED $999.99ea

Dracast LED1000 Pro Bi-Color LED Light $1,164.95

CineLED EVO "S" - 5600K $283.19

CineLED EVO "XL" - 5600K $658.38

Features: -Wireless Light Board Control through a straightforward mobile application -Auto Adjusting Light Ratios with paired mobile device -Physical Dimming Controls on each light

- Power Adapter Included - Carry Case

- Dial-up brightness 100% - 0% with no color shift -2 slide-in accessory slots on the front housing -2 built-in Sony NP-F battery mounts - Battery level button to show charging level

- Built-in digital display showing brightness level adjustments - Detachable lollipop mount with 5/8" spigot receiver - Dial-up brightness 100% - 0% with no color shift

Power / Voltage: 550W; 100-240VAC

60 W ; 100-240VAC

38 W ; DC 11-16V / AC 100-240V

45 W

Light Intensity: At 5,000K 1m: 84707 2m: 21176 3m: 9411 4m: 5294 5m: 3388 6m: 2352 7m: 1728 8m: 1323 9m: 1045 10m: 847 11m: 700 12m: 588

At 3,200K 1m: 3,800 lux 2m: 1,150 lux 3m: 530 lux 4m: 300 lux At 4,400K 1m: 7,200 lux 2m: 2,050 lux 3m 950 lux 560 lux/52 fc @ 12' (3.6 m) At 5,600K 1m: 4,200 lux 2m: 1,200 lux 3m: 530 lux 4m: 300 lux

At 5,600K 1m: 4800 lux 2m: 1250 lux 3m: 550 lux 4m: 350 lux

At 5,600K 1m: 12000 lux 2m: 3500 lux 3m: 1600 lux 4m: 950 lux

CRI: 70 95 95 95

Color Temp Range:

5000K 3,200-5,600K Variable Color Temperature

5600K 5600K

LED Beam angle: 45 Degree Beam Angle

45 Degree Beam Angle



Casing: Aluminum Aluminum Aluminum Aluminum

Dimensions (cm):

38 x 23 x 5cm Panel 10 x 10 x 20cm Back

30 x 30 x 5cm Panel

30 x 30 x 5cm Panel

31.5 x 9.05 x 1.77cm


Weight (kg): 3kg each 2.5kg 1kg 2.2kg

Product Comparison Table

Product: Genaray SpectroLED Outfit 500 Bi-Color LED Light $469.30

Genaray SpectroLED Studio 1000 Bi-Color LED Light $938.95

CineLED 1x1 DMX - 5600K $681.12

Features: - LCD display - Remote control (65’ range) - Removable diffuser

- LCD display - Remote control (65’ range) - Removable diffuser

- Built-in DMX-512 controller with RJ45 connectors - Runs from AC / DC 11-16V XLR-3P input - Dial-up brightness 100% - 0% with no color shift

Power 30 W 30 W 78 W

Light Intensity: 3,400 lux @ 3.3' (1.0 m) 6,600 lux @ 3.3 (1.0

m) At 5,600K 1m: 10100 lx

CRI: 93 93 95

Color Temp Range:

3,200-5,600K Variable Color Temperature

3,200-5,600K Variable Color Temperature

5600K

LED Beam angle: 60 60 45

Casing: (Not advertised) (Not advertised) ABS plastic

Dimensions (cm):

34.5 x 19 x 7cm Panel 34.5 x 34.5 x 7cm Panel

31 x 31 x 7cm Panel

Weight (kg): 2.63kg 3.76kg 1.81kg





Project Objectives Software Verification:

• The mobile application must control light levels of each light as a pair and individually. o The lights must turn off and on, as well as dim from 0% to 100% light output.

Firmware Verification: • The master light must communicate wirelessly with the slave light over Xbee wireless standards.

o Communication must include a transfer of status from the slave to the master and on to the android application.

o The slave light must respond to the master light’s signals by performing the intended lighting operation.

Hardware Verification: • Each LED panel must shine at a rate of 1500 lux at a distance of 3 meters. • The LED panel hardware dimmer switch, must override software control.

o The hardware must report back to the software application that hardware control has interrupted software control.

• LED dimming must not produce any artifacts or strobing on video recording. o This strobing effect must not be seen at any dimming level.


Specifications Physical Specifications

Features: -Wireless Light Board Control through a straightforward mobile application -Auto Adjusting Light Ratios with paired mobile device -Physical Dimming Controls on each light

Power/Voltage Power Supply Plug Type Power Cord Length

550W; 100-240VAC US Standard Three Prong Plug 3m

Light Intensity At 5,000K Minimum Values 1m: 84707 lux 2m: 21176 lux 3m: 9411 lux 4m: 5294 lux 5m: 3388 lux 6m: 2352 lux

7m: 1728 lux 8m: 1323 lux 9m: 1045 lux 10m: 847 lux 11m: 700 lux 12m: 588 lux

Color Temperature: Light Temperature CRI

5000k Fixed 70

LED Beam angle: 110 Degree Beam Angle without reflector

45 Degree Beam Angle with reflector

Temperature Operating Temperature Maximum Surface Temperature

30 – 110 degrees Fahrenheit < 150 degrees Fahrenheit

Wireless Effective Range: 6m Light to Light : Zigbee Wireless Coordinator(Master) and router(Slave) Light to Mobile : Wi-Fi 802.XX communication

Light to Light : Master contains Zigbee Coordinator to set Network ID Light to Mobile : Slave contains Zigbee router only, allows communication between Master and Slave

Weight Full Fixture Weight 3kg

Size Panel Back Heat Sink Heat Sink Blades Mounting Pintle(In inches) Handles Handle Mounting Bracket

38 x 23 x 5cm 10 x 10 x 20cm 23 x 23 x 5cm 5 x 0.3cm -5/8" Stud with 1/4"-20 Threaded Top 1.27cm diameter 23cm Length L shaped bracket 8 x 5 x 1.27cm

Build Materials Fixture Housing Heat Sink Handles

Aluminum Aluminum Aluminum

Manual Control Switch Open Position Closed Position

Fixture is controlled by potentiometer located on the back panel. Android Mobile Application


Physical Specifications

Dimmer Dial Potentiometer based dial Counter Clockwise Turn Clockwise Turn

Only functional in Manual Mode Lowers light level to minimum Raises light level to maximum

On/Off Switch This switch is the hard On/Off. Cannot turn on via mobile application if switch is OFF. Closed, On Position Open, Off Position

Light is powered on Light is powered off

LED Status Indicator Displays Light functional Mode. All blinking indications will have a duration of 5 seconds. OFF Blinking Blue Blinking Yellow Solid RGB Value

Manual Control Mode Connectivity Issue Between Light and Mobile Device Connectivity Issue Between Slave and Master Light Auto Control Mode from Mobile Application by Group

Operating Environment For Interior Use Only Not for use in wet or damp environments Recommend turning off lights every 8 hours for 1 hour. HANDLE WITH CARE light can be hot DO NOT DROP Lights are not designed for rugged use


User Interface Hardware Device User Interface Physical mechanical switch for power RGB LED status light Potentiometer controls light dimming level as well as selects for Application Control mode. RGB LED Status Light Operations Displays Light functional Mode. All blinking indications will have a duration of 5 seconds. OFF Manual Control Mode Blinking Blue Connectivity Issue Between Light

and Mobile Device Blinking Yellow Connectivity Issue Between Slave

and Master Light Solid RGB Value Auto Control Mode from Mobile

Application by Group

Software Application User Interface Information blocks for both the master and the slave light Automatic mode for mobile device camera controlled dimming On/Off switch sets both the master and the slave light down to 0% brightness. Main Light Seekbar controls the brightness of the main light Slave Light Seekbar controls the brightness of the Slave light


Theory Hardware We are able to interface with several components and sensors using a microprocessor (LPC4088). We will reduce the amount of flicker the LED produces by using a constant current driver (PT4115). To get to the target light level, we will use 22 chains of 3 LEDs per chain, for a total of 66 LEDs (XLAMP). Each LED needs 9 volts of forward voltage and approximately 1 amp of current. Each driver is rated at 30 volt max and max 1 amp constant current driver. The Driver sets the light level based on a PWM wave coming from the microcontroller. We also have a 200Kohm thermistor to check for the temperature of the heat sink to control the active heat sink system or to turn of the system all together.

Firmware: Our design will be incorporating a real-time operating system (RTOS). At its core, the RTOS contains a task scheduler that allows us to execute and manage multiple tasks concurrently. For our purposes, we will be using a fixed priority scheduling algorithm to delegate tasks and switch if needed according to their effect on the system. RTOS’s are highly efficient at using resources and are able to meet critical deadlines for time-critical applications. Also, because of the built-in scheduler, we can create a system with very stable response characteristics even when changes to the code occur.

Software: The calculation of ratio will be done within a frame provided by OpenCV’s libraries, where the frame is the outline of the person. Calculating the ratio will require the application to find areas of highlights and shadows. This will be done within the given frame using rectangular areas, and taking the average brightness in this area. If the average falls above a predetermined value, considered as neutral brightness, then it will be considered an average highlight and stored for later calculations. Likewise, if the average falls below the predetermined value, then it will be considered as an average shadow. Among these averages, the application will find the max and minimum value of these stored averages and will be used as the new highlight and shadow points.


Hardware Design The hardware will be broken into many smaller, printed circuit boards for ease of manufacture and assembly. Each of these circuit boards has its own schematic. The schematics are shown under the schematic section of this document. The Control Module: The Control Module includes the power circuit and the breakout of the LPC4088 microcontroller. This module includes the pin out in order to connect to the Signal Buffer Module. The Signal Buffer: The Signal Buffer circuit takes in a 3.3V PWM wave and converts it to a 5V PWM wave. The Signal Buffer will transmit the same signal for all 22 drivers. This transfer allows all the lights to shine on the same PWM wave. The output of the Signal Buffer will connect to 1 of the 22 LED driver modules. The Dimmer Module: The LED driver module contains a PT4115 constant current driver. It’s configured to achieve 30V/1AMP dimmable output to 3 LED in series chain. The Xbee Module: In Addition to all of the modules above, we also have a Wireless communication module called the XBEE module. The XBEE module handles the interface to a Xbee chip in order to achieve a wireless communication between two lights. We need to provide 5V to the Xbee and transmit and receive line between the Xbee and the Processor.


Block Diagram


Schematic

Signal Buffer Module Inputs Description PWMB Master Input from the Microcontroller

Inputs a Pulse Width Modulation to a set of OpAmps in order to change the voltage level output to LEDs.

Outputs Description PWM(21:0) 22 outputs of the master PWM wave.

Outputs to the LED Driver dimming function Output Voltage: 5V


Control Module Inputs Description VCC 3.3 input voltage from a 3.3V regulator ADC0 Input from a Potentiometer as a manual dimming

function ADC1 Input from 200Kohm thermistor for temperature

reading of the heatsink RxInput From Xbee transmit. Takes in the status from the

Slave Light Outputs Description Tx Transmits instructions or commands to the slave

light PWM0 Master PWM for dimming function PWM1 Active Heatsink, Pump Speed Controller PWM2 Active Heatsink Radiator Fan Speed Control GPIO1 Red input for tricolor LED GPIO2 Blue input for tricolor LED GPIO3 Green input for tricolor LED


Xbee Module Inputs Description Vcc 5V input from a 5V voltage regulator Din Serial Data from the master microcontroller Outputs Description Dout Serial Data received from slave microcontroller


Control Module Inputs Description Vin 30V input from an external power supply Current Sensing Current Sensing input is a short prevention

mechanism. If current is detected going into the PT4115 within the threshold limit then the device is functional. Otherwise, if the current exceeds the current threshold, then the driver will act as an open circuit in order to prevent the chip from burning out.

Switch CMOS Chip input driven by the dimming function Dimming Dimming function controls the open and close of

the PT4115 in order to produce desired light output.

Outputs Description LED Chain Outputs for this module are only the 3 LED series

chain.


Hardware Task List Hardware Development The hardware design process is broken down by week with major and minor pieces handled by each person. We set weekly progress reports for each member’s assigned tasks which will make their way into the final report at the end of the design process. We are using the week of 19-25 September as week 1. The overall all themes by week are as follows:

1. Test and Determine if PWM will show on camera (It does, but a low pass filter fixes it) a. Lead: Adam Morris b. Sub: Andy Tran c. Time: 1 Day

2. Design PCB Breakout for the low power LPC4088 a. Lead: Andy Tran b. Sub: Adam Morris c. Time: 3-4 weeks (2 for design and 2 for verification before sending for fabrication)

3. Design PCB for high power LED Driver a. Lead: Andy Tran b. Sub: Ivan Nguyen c. Time: 3-4 weeks (2 for design and 2 for verification before sending for fabrication)

4. Build LED Array Housing with integrated active heat sink a. Lead: Andy Tran b. Sub: Adam Morris c. Time: 1 week

5. Build and test LED Array a. Lead: Andy Tran b. Sub: Loc Hinh c. Time: 2-3 days

6. Test basic functionality of PCBs a. Lead: Andy Tran b. Sub: Adam Morris c. Time: 2-3 weeks ( allowing time for redesign and test)

7. Integrate LED Array with Heat sink, low and high power PCBs a. Lead: Andy Tran b. Sub: Loc Hinh, Ivan Nguyen, Adam Morris c. Time: 1 week

8. Test Each light for basic functionality a. Lead: Andy Tran b. Sub: Loc Hinh, Ivan Nguyen, Adam Morris c. Time: 3 weeks (including time for full verification process)


Firmware Design The following will be the threads we are considering to implement into our design as well as their descriptions (subject to change): Thread Description Heat Sink Temperature Check Temperature will take the value of our onboard

200k ohm thermometer resistor and be fed into the ADC. We will check if this value is equal or higher than a pre-determined value. If yes, then we will set a flag that our LED status thread will monitor

Analog Dimming Each manual dial (potentiometer) input will be read into the ADC. We will output a PWM wave proportional to the value we received. This will ultimately drive our brightness and dimming level of our light

Wi-Fi Communication This thread will connect to a mobile device over Wi-Fi communications and transmit status data and receive light level instructions from the mobile device

Xbee Communication This thread will initialize and establish connection between the master and slave light. The master will transmit light data to the slave and receive status updates from the slave

Updating LED status This thread updates the LED status lights on our panel by checking the flags set by other threads. It will also change the LED lights if there are any issues with heating or connectivity


Firmware Flowchart Initialize Hardware Flowchart

Initialize Peripheral Flowchart


Main Loop Flowchart


Firmware Task List Firmware Development

1. Design Algorithm for light step up and down through PWM output. a. Lead: Ivan Nguyen b. Sub: Andy Tran c. Time: 2 weeks

2. Design and implement Board communications for peripheral elements a. Lead: Ivan Nguyen b. Sub: Loc Hinh c. Time: 3-4 weeks

3. Implement manual control overrides a. Lead: Ivan Nguyen b. Sub: Adam Morris c. Time: 2 weeks

4. Research WiFi and Xbee communications from mobile applications a. Lead: Ivan Nguyen b. Sub: Loc Hinh c. Time: 2-3 weeks

5. Implement WiFi communications with master light a. Lead: Ivan Nguyen b. Sub: Loc Hinh, Andy Tran c. Time: 3 weeks

6. Implement Xbee Control for each light a. Lead: Ivan Nguyen b. Sub: Andy Tran c. Time: 2 weeks

7. Test Wifi and Xbee communications a. Lead: Ivan Nguyen b. Sub: Andy Tran, Loc Hinh, Adam Morris c. Time: 3 weeks


Software Design Software will be written on the Java platform for Android 4.4 and higher. Wifi will be setup as soon as the application starts using the WifiP2pManager class. Setting up the application such that it is allowed to use the Wifi P2P protocol will be as follows*:

1. Request permission to use Wifi on the device hardware, and declare application to have correct minimum SDK version in the Android manifest.

2. Check if Wifi P2P is supported and on. This will be done by checking the broadcast receiver when WIFI_P2P_STATE_CHANGED_ACTION has been received.

3. On the current activity onCreate() method, create an instance of WifiP2pManager and register application with the Wifi P2P framework by calling the initialize() method.

a. The initialize() method will return a WifiP2pManager.Channel, which connects the application to the Wifi P2P framework.

b. Create another instance of the broadcast receiver using the WifiP2pManager and WifiP2pManager.Channel.

i. Allows current activity to be notified of any events. Also allows the manipulation of the device’s Wifi state.

4. Create an intent filter and add the same intents that the broadcast receiver checks for.

5. Register the broadcast receiver in the onResume() method and unregister in the onPause() method.

*Discovering peers will use the discoverPeers() method, and will return an onSuccess() or onFailure() through WifiP2pManager.ActionListener. On success of peer discovery, the application needs to listen for a WIFI_P2P_PEERS_CHANGED_ACTION and will use the method requestPeers() to obtain a list of discovered peers, in the case of the project, we only need to look for the light on the peer list.

*Once the light has been found in the peer list, the connection will be established using the connect() method. WifiP2pConfig object will be required for that method call because the WifiP2pConfig object contains the information of the device to connect to. Using the WifiP2pManager.ActionListener, the application will be notified on a success or failure in connection.


*To transfer data using Wifi P2P, the following steps must be followed: 1. Create a ServerSocket on a background thread.

a. This object waits on the client on a particular port. This wastes CPU time. 2. Create a Socket client.

a. This object communicates to the ServerSocket, and uses the ServerSocket’s IP and port to connect to the server device.

3. Send data from client to server using byte streams. a. 2 bytes of data at a time.

4. ServerSocket waits for client connection through the accept() method. This method eats up CPU time, so it should be run on a separate thread.

a. On connection, the ServerSocket can receive data from client, which can be used to be stored or present to the user.

OpenCV library will be used for image recognition, which requires the use of the device camera. It will detect a person and the brightness on that person. When a ratio is selected, an image will be snapped, the areas that have high and low brightness will be used to calculate a ratio of shadow and highlights, transmit this ratio via Wifi, and repeat until a the ratio reaches 1:1, which is no shadow. This is a brute force method where it may take a noticeable period of time to reach the desired ratio. The calculation of ratio will be done within a frame provided by OpenCV’s libraries, where the frame is the outline of the person. Calculating the ratio will require the application to find areas of highlights and shadows. This will be done within the given frame using rectangular areas, and taking the average brightness in this area. If the average falls above a predetermined value, considered as neutral brightness, then it will be considered an average highlight and stored for later calculations. Likewise, if the average falls below the predetermined value, then it will be considered as an average shadow. Among these averages, the application will find the max and minimum value of these stored averages and will be used as the new highlight and shadow points. On the main activity, the main and side light seek bars will produce a percentage number which will be transmitted through Wifi whenever the seek bars have a different value. The auto and on/off button will listen for a click event and will transmit through Wifi. A background thread will run where it will receive data asynchronously from the lights to update its status’. *Setup guide taken from http://developer.android.com/guide/topics/connectivity/wifip2p.html

http://developer.android.com/guide/topics/connectivity/wifip2p.html


Software Flowchart


Software Task List Software Development The software design process is also broken down by week. The main difference is there will be less development at the beginning and more near the end of the semester after the printed circuit boards return and are functional. The numbered list starts again with week 1 being the week of 19 September.

1. Design Basic Android app functionality with splash screen a. Lead: Loc Hinh b. Sub: Adam Morris c. Time: 2-3 weeks

2. Design and test app based led control sliders a. Lead: Loc Hinh b. Sub: Ivan Nguyen c. Time: 2 weeks

3. Design Communications Frame between the mobile application and the hardware a. Wifi Direct or Wifi P2P b. Lead: Ivan Nguyen c. Sub: Andy Tran d. Time: 2-3 weeks

4. Implement Wifi communications to mobile application a. Lead: Loc Hinh b. Sub: Andy Tran c. Time: 2 weeks

5. Research and port an openCV implementation to Android a. Lead: Loc Hinh b. Sub: Andy Tran, Adam Morris c. Time: 3-4 weeks

6. Test openCV support on app side a. Lead: Loc Hinh b. Sub: Andy Tran, Adam Morris c. Time: 2-3 weeks

7. Test openCV auto mode with physical device a. Lead: Loc Hinh b. Sub: Adam Morris, Andy Tran, Ivan Nguyen c. Time: 2-3 weeks


GANTT Diagram

ACTIVITY START DURATION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Hardware 1. Test and Determine if PWM will show on camera 1 1 2. Design PCB Breakout for the low power LPC4088 2 4 3. Design PCB for high power LED Driver 2 4 4. Build LED Array Housing with integrated active heat sink 6 1 5. Build and test LED Array 7 0.5 6. Test basic functionality of PCBs 9 3 7. Integrate LED Array with Heat sink, low and high power PCBs 12 1 8. Test Each light for basic functionality 13 3 Software 1. Design Basic Android app functionality with splash screen 1 3 2. Design and test app based led control sliders 4 2 3. Design Communications Frame between app and HW 6 3 4. Implement Wifi communications to mobile application 9 2 5. Research and port an openCV implementation to Android 7 4 6. Test openCV support on app side 11 3 7. Test openCV auto mode with physical device 14 3 Firmware 1. Design Algorithm for light step up and down through PWM output. 1 2 2. Design and implement Board communications for peripheral elements 3 4 3. Implement manual control overrides 7 2 4. Research WiFi and Xbee communications from mobile applications 9 3 5. Implement WiFi communications with master light 12 3 6. Implement Xbee Control for each light 9 2

7. Test Wifi and Xbee communications 12 3


Costs 1. Major Component Costs

# Part Cost Per Unit Number of

Units Total

1 PT4115 $0.04 1000 $39.99 2 LPC4088 chip $8.18 1000 $8,179.00

3 CREE XLAMP LED $1.23 66000 $81,180.00

4 Xbee S1 Module $19.00 1000 $19,000.00 5 Metal Case $60.00 1000 $60,000.00 6 Misc. Parts $50.00 1000 $50,000.00

Total Cost $218,398.99 2. Development Wage Costs

# Number of Engineers

Cost Per Engineer per month

Development Time in Months

Total Development

Cost 1 4 $5,000 6 $120,000.00 3. Assembly Costs

# Part Cost Per Unit Number of

Units Total 1 PCB Assembly $25.00 1004 $25,100.00

2 Finished Unit

Labor $30.00 1000 $30,000.00 3 Total Assembly $55,100.00

4. Total Cost of Producing 1000 Units $393,498.99 5. Single Unit Cost $393.49


Conclusions Hardware Conclusion:

The Good: 1) The design of the PCB is modular so we can have difference team member working on difference part of the PCB. Also we can test out each module without depend on the previous module completion therefore if we can do something like break out the LPC 4088 we can substitute to a professionally done one and still have the project working in the end. 2) Using mbed as our development platform it has revision control, so we can develop the firmware without worry that we make a mistake in the end and the project will not work at all. 3) We can develop out firmware, software, and hardware in parallel, therefore one team member will not hold up the entire production phase for next semester.

The Bad: 1) The LEDs driver we order from China therefore, we anticipate that about 10 percent of failure and with the time we might not get a second order in time to fix it. So we order more than we actually need to ensure that we always of spare LEDs driver if some of them got burn or not work at all. 2) The PCB pad for the LEDs driver is not common, therefore we might need to create custom pad for the design which might not be successful at first try. We going to have all of our PCB printed in the United States, so we can try to make the correct pad for multiple time. 3) The LEDs driver pin out are tiny and close to each other, I can see that we might short out some of the chip if we are not careful. The solution is to dedicate one team member to solder the LEDs on the pad as he got the hang of thing it might minimize the change of failure. 4) The Break out for the LPC4088 might be too difficult for our group because none of us have any experience of break out a microprocessor before. The solution is to have a LPC4088 header board as back up if our break out does not work, we can use the LPC4088 header board as our final solution.

Software Conclusion:

The Good: Some positive things about this project are that Android Studio IDE comes with a large library which helps with creating the user interface. We can drag and drop functions on to the activity and program what those functions need to do. The library includes classes that let us do our initial Wifi setup and transmission with ease. The IDE also allows us to include the OpenCV library manually to be used in our Android application.


The Bad: A few concerns about the project that exist are the Wifi communication between the Android device and the Wifi module on the light. Finding a module where it is Wifi P2P/Direct ready may be a problem because we’re not sure that it exists. If any Wifi module will work, then the problem lies in understanding how Wifi P2P will work on that Wifi module. A possible solution to this predicament would be to research Wifi protocols and gain some insight as to how it works. This will alleviate any doubts that we may have for the time being, and may point us in the right direction when programming the Wifi module. Another problem is the use of OpenCV within the application. Including the library and utilizing its various functions seem like it will be another mountain to climb. The classes and methods provided are not as straightforward as it may appear, since this library helps us do a pretty sophisticated image recognition with ease. A solution would be to find example source codes on how to implement the OpenCV library into our application to work the way we need it to. Following tutorials using various OpenCV demos will help in clarifying the various functions in OpenCV.

Firmware Conclusion: The Good: As a team, we agreed to use an RTOS which will simplify the executing of multiple tasks. We will be able to create a stable system that can quickly respond to user input. This project also improved our individual organizational and communication skills. We learned how each component contributed to the whole and needed to know the technical details in order to communicate that information to the rest of the team.

The Bad: I am concerned about the PCB design and whether or not we will be able to talk to the peripherals on the board. Having no prior experience of designing one, there is a lot of room for error and I am not sure we can afford that. We also ran into trouble regarding how we will establish a Wi-Fi connection for our mobile app and exactly how to communicate data via Wi-Fi. Finally, the flowcharts were tricky to create as much of our design depended on other parts from other team members. The best solution for us as a team is to research cheap PCB producers, or at the very least create a prototype we can test. From there, we can make necessary changes and hopefully cut down costs. We also need to look into Wi-Fi protocol or use an existing Wi-Fi module to place into our design.


Appendix A

Why Use a Real-Time Operating System in MCU Applications

Introduction

Are you adding more features to each new

generation of your microcontroller application?

And are internet connectivity and touchscreen UIs

becoming mandatory? If so then it’s time to switch

to a real-time operating system (RTOS). Taking

advantage of an off-the-shelf RTOS environment

frees you up from focusing too much on low-level

peripheral control software and allows you more

resources for differentiation.

Nick LethabyOS Product Manager

Texas Instruments Incorporated

W H I T E P A P E R

Traditionally, MCU developers implement software applications around sequential processing

loops and state machines. While adequate when the MCU is performing a rather limited number

of functions, a different approach is required as MCUs integrate more memory and peripherals.

A growing number of MCU applications are now based on a Real-Time Operating Systems (RTOS).

The key driver of RTOS adoption is application complexity. An RTOS will often be used when there

are more interrupt sources, more functions, and more standard communications interfaces that

need to be supported. If the application is <64KB in size, an RTOS is not necessary. Conversely if,

the applications is 1 MB, an RTOS will likely be used.

Internal debates within development teams considering use of an RTOS for the first time are

passionate. Many MCU developers are accustomed to having intimate control over 100% of the

code base and highly optimizing every byte of code and data. It can be challenging to give up this

level of control and rely on code from a third-party. While it is unlikely that third-party software will

completely match the efficiency of a highly customized run-time, using an RTOS counterbalances

this by increasing development team productivity through greater code reuse.

This debate is analogous to “C vs. assembly language”. An experienced assembly language

programmer will typically generate faster and smaller code than a C compiler. However, using C

is almost universally considered a superior approach because the amount of effort to develop an

application is much less than when using assembly language. While it is quite possible to do a

custom RTOS implementation, it is questionable whether such an approach is optimal. The

availability of no-cost off-the-shelf RTOS solutions such as TI-RTOS and FreeRTOS™ remove any

barriers associated with product cost. Furthermore, the cost of commercial RTOS products such

as µC/OS III®, ThreadX®, SMX®, and Nucleus® is typically much lower than having in-house

engineers develop and maintain a custom RTOS implementation.

The below are five productivity advantages and top reasons to condsider using an RTOS:

1. Preemptive multitasking design paradigm: For more complex real-time applications,

especially those with a code base that is progressively enhanced in each release, the

preemptive multitasking design paradigm is superior. This design paradigm makes

response-times to each real-time event relatively independent of each other. As a result, new

functions can be added without disrupting existing hard real-time ones. In contrast, in a

sequential processing loop where each event is checked by polling, the addition of a new event

will affect the response times for all events. Although real-time response for critical events can

be maintained by use of background/foreground loops or other mechanisms to more frequently

poll critical events, more complex real-time applications designed in this way often become

very difficult to maintain and modify. Unlike a custom run-time, RTOSs are typically designed

to support a wide range of application scenarios and do not need to be modified to support

a new application.

2. Pre-tested and pre-integrated communications stacks and drivers: An RTOS will typically offer

communications stacks such as TCP/IP and USB along with drivers for these and other peripherals. Having

such software available working “out of box”, eliminates the need for developers to implement it from scratch or

spend time integrating third-party software into their run-time environment. In addition most MCU developers are

not expert in communications stacks. An RTOS that provides these allows a developer to focus on their area of

application expertise and not spend time on undifferentiated system capabilities such as internet connectivity.

3. Application portability: By providing a standardized set of stack and driver APIs that abstracts the specifics of

the underlying hardware, an RTOS makes applications much more portable. There is much less risk that applica-

tion software will get interleaved with code performing low-level accesses to peripheral control registers specific

to a device. Highly portable code increases ease-of-software reuse.

4. System-level debug and analysis tools: As an application becomes more complex, it becomes more likely

that it can behave in unanticipated ways. Excessive memory usage or leaks, delayed response to real-time

events, or greater than expected CPU loads are all problems that can occur. Problems of this nature are often

difficult to diagnose since they require a high-level understanding of system behavior and resource usage. Most

RTOSs have associated system-level debugging tools that enable application behavior and resource usage to

be examined. For example, TI-RTOS has associated tools that enable developers to look at stack usage and

compare it against how much stack was assigned to a task. This makes it straightforward to detect stack over-

flows or to optimize task stack sizes to free up RAM for other parts of the application. For a custom run-time, a

development team will need to create and maintain custom tools.

5. More efficient use of CPU resources: Simple loop-based run-times typically do a lot of polling to check

if interrupts have occurred. As a result a great deal of processor time is occupied doing nothing. Because

multitasking RTOS-based applications are interrupt-driven, it is possible to largely eliminate polling from the

application. This frees up processor resources for useful work and enables power-saving modes to be invoked

during idle periods.

If you are finding that each generation of your MCU application is adding more and more features and that

internet connectivity and touchscreen UIs are becoming mandatory, it may be time to consider switching to an

RTOS. Taking advantage of an off-the-shelf software environment like TI RTOS frees you up from focusing too

much on low-level peripheral control SW and allows more resources for differentiating your application.

2Texas Instruments

SPRY238

Important Notice: The products and services of Texas Instruments Incorporated and its subsidiaries described herein are sold subject to TI’s standard terms and conditions of sale. Customers are advised to obtain the most current and complete information about TI products and services before placing orders. TI assumes no liability for applications assistance, customer’s applications or product designs, software performance, or infringement of patents. The publication of information regarding any other company’s products or services does not constitute TI’s approval, warranty or endorsement thereof.

The platform bar is a trademark of Texas Instruments. ThreadX is a registered trademark of Express Logic, Inc. Nucleus is a registered trademark of Mentor Graphics Corporation. µC/OS III® is a registered trademark of Micrium, Inc. SMX is a registered trademark of Micro Digital, Inc. FreeRTOS is a trademark of Real Time Engineers, Ltd.

E010208

© 2013 Texas Instruments Incorporated

IMPORTANT NOTICE

Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and otherchanges to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latestissue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current andcomplete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of salesupplied at the time of order acknowledgment.

TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s termsand conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessaryto support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarilyperformed.

TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products andapplications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provideadequate design and operating safeguards.

TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, orother intellectual property right relating to any combination, machine, or process in which TI components or services are used. Informationpublished by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty orendorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of thethird party, or a license from TI under the patents or other intellectual property of TI.

Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alterationand is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altereddocumentation. Information of third parties may be subject to additional restrictions.

Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or servicevoids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.TI is not responsible or liable for any such statements.

Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirementsconcerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or supportthat may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards whichanticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might causeharm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the useof any TI components in safety-critical applications.

In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is tohelp enable customers to design and create their own end-product solutions that meet applicable functional safety standards andrequirements. Nonetheless, such components are subject to these terms.

No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the partieshave executed a special agreement specifically governing such use.

Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use inmilitary/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI componentswhich have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal andregulatory requirements in connection with such use.

TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use ofnon-designated products, TI will not be responsible for any failure to meet ISO/TS16949.

Products Applications

Audio www.ti.com/audio Automotive and Transportation www.ti.com/automotive

Amplifiers amplifier.ti.com Communications and Telecom www.ti.com/communications

Data Converters dataconverter.ti.com Computers and Peripherals www.ti.com/computers

DLP® Products www.dlp.com Consumer Electronics www.ti.com/consumer-apps

DSP dsp.ti.com Energy and Lighting www.ti.com/energy

Clocks and Timers www.ti.com/clocks Industrial www.ti.com/industrial

Interface interface.ti.com Medical www.ti.com/medical

Logic logic.ti.com Security www.ti.com/security

Power Mgmt power.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense

Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video

RFID www.ti-rfid.com

OMAP Applications Processors www.ti.com/omap TI E2E Community e2e.ti.com

Wireless Connectivity www.ti.com/wirelessconnectivity

Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265Copyright © 2013, Texas Instruments Incorporated

http://www.ti.com/audio

http://www.ti.com/automotive

http://amplifier.ti.com

http://www.ti.com/communications

http://dataconverter.ti.com

http://www.ti.com/computers

http://www.dlp.com

http://www.ti.com/consumer-apps

http://dsp.ti.com

http://www.ti.com/energy

http://www.ti.com/clocks

http://www.ti.com/industrial

http://interface.ti.com

http://www.ti.com/medical

http://logic.ti.com

http://www.ti.com/security

http://power.ti.com

http://www.ti.com/space-avionics-defense

http://microcontroller.ti.com

http://www.ti.com/video

http://www.ti-rfid.com

http://www.ti.com/omap

http://e2e.ti.com

http://www.ti.com/wirelessconnectivity

30V, 1.2A Step-down High Brightness

LED Driver with 5000:1 Dimming

China Resources Powtech (Shanghai) Limited WWW.CRPOWTECH.COM Page 1 PT4115_DS Rev EN_2.9

PT4115

GENERAL DESCRIPTION

The PT4115 is a continuous conduction mode inductive

step-down converter, designed for driving single or

multiple series connected LED efficiently from a

voltage source higher than the total LED chain voltage.

The device operates from an input supply between 6V

and 30V and provides an externally adjustable output

current of up to 1.2A. Depending upon the supply

voltage and external components, the PT4115can

provide more than 30 watts of output power.

The PT4115 includes the power switch and a high-side

output current sensing circuit, which uses an external

resistor to set the nominal average output current, and a

dedicated DIM input accepts either a DC voltage or a

wide range of pulsed dimming. Applying a voltage of

0.3V or lower to the DIM pin turns the output off and

switches the device into a low current standby state.

The PT4115 is available in SOT89-5 and ESOP8

packages.

FEATURES

Simple low parts count Wide input voltage range: 6V to 30V Up to 1.2A output current Single pin on/off and brightness control using DC

voltage or PWM Up to 1MHz switching frequency Typical 5% output current accuracy Inherent open-circuit LED protection High efficiency (up to 97%) High-Side Current Sense Hysteretic Control: No Compensation Adjustable Constant LED Current ESOP8 package for large output power application RoHS compliant

APPLICATIONS

Low voltage halogen replacement LEDs

Automotive lighting

Low voltage industrial lighting

LED back-up lighting

Illuminated signs

SELV lighting

LCD TV backlighting

ORDERING INFORMATION

PACKAGE TEMPERATURE

RANGE

ORDERING PART

NUMBER

TRANSPORT

MEDIA MARKING

SOT89-5 -40 oC to 85

oC

PT4115B89E:A type

PT4115B89E-B:B type

Tape and Reel

1000 units

PT4115

xxxxxX

ESOP8 -40 oC to 85

oC

PT4115BSOH:A type

PT4115BSOH-B:B type

Tape and Reel

2500 units

PT4115

xxxxxX

Note:

TYPICAL APPLICATION CIRCUIT

PT4115PT4115

VIN CSN SW

DIM

GND

RS

L

CIN

VIN

D68uH

100uF

AC12-18V

DC6-30V

0.13Ω3WLED

xxxxxX

Assembly Factory Code

Lot Number




PT4115

PIN ASSIGNMENT

PIN DESCRIPTIONS

PIN No. PIN

NAMES DESCRIPTION

1 SW Switch Output. SW is the drain of the internal N-Ch MOSFET switch.

2 GND Signal and power ground. Connect directly to ground plane.

3 DIM Logic level dimming input. Drive DIM low to turn off the current regulator.

Drive DIM high to enable the current regulator.

4 CSN Current sense input

5 VIN Input Supply Pin. Must be locally bypassed.

- Exposed PAD Internally connected to GND. Mount on board for lower thermal resistance.

ESOP8 4,5 NC No connection

ABSOLUTE MAXIMUM RATINGS (note1)

SYMBOL ITEMS VALUE UNIT

VIN Supply Voltage -0.3~45 V

SW Drain of the internal power switch -0.3~45 V

CSN Current sense input (Respect to VIN) +0.3~(-6.0) V

DIM Logic level dimming input -0.3~6 V

ISW Switch output current 1.5 A

PDMAX Power Dissipation (Note 2) 1.5 W

PTR Thermal Resistance, SOT89-5 θJA 45 oC /W

PTR Thermal Resistance, ESOP8 θJA 40 oC /W

TJ Operation Junction Temperature Range -40 to 150 oC

TSTG Storage Temperature -55 to 150 oC

ESD Susceptibility (Note 3) 2 kV

1

2

3

4 5

6

7

8PT

4115

CSN

VIN

SW

NC NC

GNDP

GNDA

DIM

ESOP8




PT4115

RECOMMENDED OPERATING RANGE

SYMBOL ITEMS VALUE UNIT

VIN VDD Supply Voltage 6 ~ 30 V

TOPT Operating Temperature -40 to +85 oC

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Recommended

Operating Range indicates conditions for which the device is functional, but do not guarantee specific performance

limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which

guarantee specific performance limits. This assumes that the device is within the Operating Range. Specifications are

not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device

performance.

Note 2: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX, θJA,

and the ambient temperature TA. The maximum allowable power dissipation is PDMAX = (TJMAX - TA)/ θJA or the

number given in Absolute Maximum Ratings, whichever is lower.

Note 3: Human body model, 100pF discharged through a 1.5kΩ resistor.

ELECTRICAL CHARACTERISTICS (Note 4, 5)

The following specifications apply for VIN=12V, TA=25 oC, unless specified otherwise.

SYMBOL ITEMS CONDITIONS Min. Typ. Max. UNIT

VIN Input Voltage 6 30 V

VUVLO Under voltage lock out VIN falling 5.1 V

VUVLO, HYS UVLO hysterisis VIN rising 500 mV

FSW Max. Switching Frequency 1 MHz

Current Sense

VCSN Mean current sense

threshold voltage VIN-VCSN

A type 95 98 101 mV

B type 99 102 105 mV

VCSN_hys Sense threshold hysteresis ±15 %

ICSN CSN Pin Input Current VIN-VCSN=50mV 8 µA

Operating Current

IOFF Quiescent supply current

with output off VDIM<0.3V 95 µA

DIM Input

VDIM Internal supply voltage DIM floating 5 V

VDIM_H DIM input voltage High 2.5 V

VDIM_L DIM input voltage Low 0.3 V

VDIM_DC DC brightness control 0.5 2.5 V

fDIM Max. DIM Frequency fOSC=500kHz 50 kHz

DPWM_LF

Duty cycle range of low

frequency dimming fDIM =100Hz 0.02% 1

Brightness control range 5000:1




PT4115

ELECTRICAL CHARACTERISTICS (Continued) (Note 4, 5)

SYMBOL ITEMS CONDITIONS Min. Typ. Max. UNIT

DIM Input

DPWM_HF Duty cycle range of high

frequency dimming fDIM =20KHz

4% 1

Brightness control range 25:1

RDIM DIM pull up resistor to Internal

supply voltage 200 KΩ

IDIM_L DIM input leakage low VDIM = 0 25 uA

Output Switch

RSW SW On Resistance VIN=12V 0.6 Ω

VIN=24V 0.4

ISWmean Continuous SW Current 1.2 A

ILEAK SW Leakage Current 0.5 5 µA

Thermal Shutdown

TSD Thermal Shutdown Threshold 160

TSD-hys Thermal Shutdown hysteresis 20

Note 4: Typical parameters are measured at 25˚C and represent the parametric norm.

Note 5: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.

SIMPLIFIED BLOCK DIAGRAM




PT4115

OPERATION DESCRIPTION

The device, in conjunction with the coil (L1) and

current sense resistor (RS), forms a self oscillating

continuous-mode buck converter.

When input voltage VIN is first applied, the initial

current in L1 and RS is zero and there is no output from

the current sense circuit. Under this condition, the

output of CS comparator is high. This turns on an

internal switch and switches the SW pin low, causing

current to flow from VIN to ground, via RS, L1 and the

LED(s). The current rises at a rate determined by VIN

and L1 to produce a voltage ramp (VCSN) across RS.

When (VIN-VCSN) > 115mV, the output of CS

comparator switches low and the switch turns off. The

current flowing on the RS decreases at another rate.

When (VIN-VCSN) < 85mV, the switch turns on again

and the mean current on the LED is determined by

85 115

2( ) / 100 /S SmV R mV R+ = .

The high-side current-sensing scheme and on-board

current-setting circuitry minimize the number of

external components while delivering LED current with

±5% accuracy, using a 1% sense resistor.

The PT4115 allow dimming with a PWM signal at the

DIM input. A logic level below 0.3V at DIM forces

PT4115 to turn off the LED and the logic level at DIM

must be at least 2.5V to turn on the full LED current.

The frequency of PWM dimming ranges from 100Hz to

more than 20 kHz.

The DIM pin can be driven by an external DC voltage

(VDIM) to adjust the output current to a value below the

nominal average value defined by RS. The DC voltage

is valid from 0.5V to 2.5V. When the dc voltage is

higher than 2.5V, the output current keeps constant.

The LED current also can be adjusted by a resistor

connected to the DIM pin. An internal pull-up resistor

(typical 200KΩ) is connected to a 5V internal regulator.

The voltage of DIM pin is divided by the internal and

external resistor.

The DIM pin is pulled up to the internal regulator (5V)

by a 200KΩ resistor. It can be floated at normal

working. When a voltage applied to DIM falls below

the threshold (0.3V nom.), the output switch is turned

off. The internal regulator and voltage reference remain

powered during shutdown to provide the reference for

the shutdown circuit. Quiescent supply current during

shutdown is nominally 95uA and switch leakage is

below 5uA.

Additionally, to ensure the reliability, the PT4115 is

built with a thermal shutdown (TSD) protection and a

thermal pad. The TSD protests the IC from over

temperature (160). Also the thermal pad enhances

power dissipation. As a result, the PT4115 can handle a

large amount of current safely.




PT4115

TYPICAL PERFORMANCE CHARACTERISTICS

8 10 12 14 16 18 20 22 24 26 28 3075%

80%

85%

90%

95%

100%

Effic

ien

cy

Supply Voltage Vin(V)

Efficiency1,3 and 7 LEDs

L=47uH

Rs=0.13ohm

1LED

3 LEDs

7LEDs

5 10 15 20 25 304.5

4.6

4.7

4.8

4.9

5.0

5.1

5.2

5.3

5.4

5.5

Vd

im(V

)


Vdim vs Supply Voltage

-40 -20 0 20 40 60 80 100 1205.00

5.05

5.10

5.15

5.20

5.25

5.30

Vd

im(V

)

Temperature(Deg C)

Vdim vs Temperature




PT4115

5 15 25 350.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Rsw

(o

hm

)


Rsw vs Supply Voltage

0 5 10 15 20 25 300

50

100

150

200

250

Iin

(u

A)


Supply Current vs Supply Voltage

0 1 2 3 4 50

100

200

300

400

500

600

700

800

R=0.33ohmLE

D c

urr

ent (m

A)

Dim Pin Voltage (V)

LED Current vs Vdim

R=0.13ohm




PT4115

5 10 15 20 25 301.10

1.12

1.14

1.16

1.18

1.20

1.22

1.24

7LEDs6LEDs5LEDs

4LEDs

3LEDs2LEDs

Ou

tpu

t C

urr

en

t

Supply Voltage(V)

Output Current L=27uH Rcs=0.0825ohm

1LED

5 10 15 20 25 30-8%

-7%

-6%

-5%

-4%

-3%

-2%

-1%

0%

1%

2%

3%

7LEDs5LEDs

6LEDs

4LEDs

3LEDsOu

tpu

t C

urr

en

t D

evia

tio

nSupply Voltge(V)


1LED

2LEDs

5 10 15 20 25 300%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%7LEDs

6LEDs5LEDs

3LEDs

4LEDs2LEDs

Du

ty C

ycle


Duty Cycle L=27uH R=0.0825ohm

1LED

5 10 15 20 25 300

100

200

300

400

500

600

700

800

900

1000

7LEDs

2LEDs 3LEDs

5LEDs 6LEDs4LEDs

Sw

itch

ing

Fre

qu

en

cy(k

HZ

)


Switching Frequency L=27uH R=0.0825ohm

1LED

5 10 15 20 25 30710

720

730

740

750

760

770

780

790

800

7LEDs

3LEDs

5LEDs2LEDs

6LEDs4LEDsOu

tpu

t C

urr

en

t(m

A)



1LED

5 10 15 20 25 30-6%

-4%

-2%

0%

2%

4%

6%

2LEDs

4LEDs 6LEDs

7LEDs

5LEDs

3LEDs

1LED

Ou

tpu

t C

urr

en

t D

evia

tio

n

Supply Voltage(V)





PT4115

8 10 12 14 16 18 20 22 24 26 28 300%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

7LEDs

6LEDs5LEDs

4LEDs

3LEDs

Du

ty C

ycle


Duty Cycle L=47uH Rcs=0.13ohm

1LED

2LEDs

8 10 12 14 16 18 20 22 24 26 28 300

100

200

300

400

500

600

700

800

900

7LEDs

6LEDs5LEDs

4LEDs

3LEDs

2LEDs

1LED

Sw

itch

Fre

qu

en

cy(k

Hz)


Switch Frequency L=47uH Rcs=0.13ohm

5 10 15 20 25 30-6%

-4%

-2%

0%

2%

4%

6%

8%

7LEDs

3LEDs6LEDs

5LEDs4LEDs

2LEDs

1LED

Ou

tpu

t C

urr

en

t D

evia

tio

n

Supply Voltage


5 10 15 20 25 300%

10%

20%

30%

40%

50%

60%

70%

80%

90%7LEDs

6LEDs5LEDs

4LEDs

3LEDs

Du

ty C

ycle


Duty Cycle L=100uH R=0.33ohm

1LED

2LEDs

5 10 15 20 25 300

100

200

300

400

500

600

700

800

900

1000

7LEDs6LEDs5LEDs

4LEDs

3LEDs

2LEDs

1LED

Sw

itch

Fre

qu

en

cy(k

Hz)


Switch Frequency L=100uH R=0.33ohm




PT4115




PT4115

APPLICATION NOTES

Setting nominal average output current with

external resistor RS

The nominal average output current in the LED(s) is

determined by the value of the external current sense

resistor (RS) connected between VIN and CSN and is

given by:

RsIOUT /1.0 )082.0( Rs

This equation is valid when DIM pin is float or applied

with a voltage higher than 2.5V (must be less than 5V).

Actually, RS sets the maximum average current which

can be adjusted to a less one by dimming.

Output current adjustment by external DC control

voltage

The DIM pin can be driven by an external dc voltage

(VDIM), as shown, to adjust the output current to a

value below the nominal average value defined by RS.

PT4115PT4115

VIN CSN SW

DIM

GND

RS

L

D68uH

0.13Ω3W

LED

VIN

The average output current is given by:

Rs

VI DIM

OUT

5.2

1.0)5.25.0( VVV DIM

Note that 100% brightness setting corresponds to:

)55.2( VVV DIM

Output current adjustment by PWM control

A Pulse Width Modulated (PWM) signal with duty

cycle PWM can be applied to the DIM pin, as shown

below, to adjust the output current to a value below the

nominal average value set by resistor RS:

Rs

DI OUT

1.0

)55.2%,1000( VVVD pulse

Rs

DVI

pulse

OUT

5.2

1.0

)5.25.0%,1000( VVVD pulse

PT4115PT4115

VIN CSN SW

DIM

GND

RS

L

D68uH

0.13Ω3W

LED

VIN

PWM dimming provides reduced brightness by

modulating the LED’s forward current between 0% and

100%. The LED brightness is controlled by adjusting

the relative ratios of the on time to the off time. A 25%

brightness level is achieved by turning the LED on at

full current for 25% of one cycle. To ensure this

switching process between on and off state is invisible

by human eyes, the switching frequency must be

greater than 100 Hz. Above 100 Hz, the human eyes

average the on and off times, seeing only an effective

brightness that is proportional to the LED’s on-time

duty cycle. The advantage of PWM dimming is that the

forward current is always constant, therefore the LED

color does not vary with brightness as it does with

analog dimming. Pulsing the current provides precise

brightness control while preserving the color purity.

The dimming frequency of PT4115 can be as high as 20

kHz.




PT4115

Shutdown mode

Taking the DIM pin to a voltage below 0.3V will turn

off the output and the supply current will fall to a low

standby level of 95μA nominal.

Soft-start

An external capacitor from the DIM pin to ground will

provide additional soft-start delay, by increasing the

time taken for the voltage on this pin to rise to the

turn-on threshold and by slowing down the rate of rise

of the control voltage at the input of the comparator.

Adding capacitance increases this delay by

approximately 0.8ms/nF.

Inherent open-circuit LED protection

If the connection to the LED(s) is open-circuited, the

coil is isolated from the SW pin of the chip, so the

device and LED will not be damaged.

Capacitor selection

A low ESR capacitor should be used for input

decoupling, as the ESR of this capacitor appears in

series with the supply source impedance and lowers

overall efficiency. This capacitor has to supply the

relatively high peak current to the coil and smooth the

current ripple on the input supply. A minimum value of

4.7uF is acceptable if the DC input source is close to

the device, but higher values will improve performance

at lower input voltages, especially when the source

impedance is high. For the rectified AC input, the

capacitor should be higher than 100uF and the tantalum

capacitor is recommended. The input capacitor should

be placed as close as possible to the IC.

For maximum stability over temperature and voltage,

capacitors with X7R, X5R, or better dielectric are

recommended. Capacitors with Y5V dielectric are not

suitable for decoupling in this application and should

NOT be used.

A suitable Murata capacitor would be

GRM42-2X7R475K-50.

The following web sites are useful when finding

alternatives:

www.murata.com

www.t-yuden.com

www.avxcorp.com

Inductor selection

Recommended inductor values for the PT4115 are in

the range 27uH to 100uH.

Higher values of inductance are recommended at lower

output current in order to minimize errors due to

switching delays, which result in increased ripple and

lower efficiency. Higher values of inductance also

result in a smaller change in output current over the

supply voltage range. (See graphs). The inductor should

be mounted as close to the device as possible with low

resistance connections to the SW and VIN pins.

The chosen coil should have a saturation current higher

than the peak output current and a continuous current

rating above the required mean output current.

Following table gives the guideline on inductor

selection:

Load current Inductor Saturation current

Iout>1A 27-47uH

1.3-1.5 times of load

current

0.8A<Iout≤1A 33-82uH

0.4A<Iout≤0.8A 47-100uH

Iout≤0.4A 68-220uH

Suitable coils for use with the PT4115 are listed in the

table below:

Part

No.

L

(uH)

DCR

(Ω)

ISAT

(A) Manufacturer

MSS1038-333 27 0.089 2.48

CoilCraft

www.coilcraft.com

MSS1038-333 33 0.093 2.3

MSS1038-473 47 0.128 2

MSS1038-683 68 0.213 1.6

MSS1038-104 100 0.304 1.3

The inductor value should be chosen to maintain

operating duty cycle and switch 'on'/'off' times within

the specified limits over the supply voltage and load

current range.

The following equations can be used as a guide.

SW Switch 'On' time

)( swavgLEDIN

ONRrLRsIVV

ILT

SW Switch 'Off' time

)( rLRsIVV

ILT

avgDLED

OFF

Where:

L is the coil inductance (H)

rL is the coil resistance (Ω )

RS is the current sense resistance (Ω )

Iavg is the required LED current (A)

http://dict.iciba.com/tantalum/




PT4115

Δ I is the coil peak-peak ripple current (A) Internally

set to 0.3 x Iavg

VIN is the supply voltage (V)

VLED is the total LED forward voltage (V)

RSW is the switch resistance (Ω ) =0.6Ω nominal

VD is the diode forward voltage at the required load

current (V)

Diode selection

For maximum efficiency and performance, the rectifier

(D1) should be a fast low capacitance Schottky diode

with low reverse leakage at the maximum operating

voltage and temperature.

They also provide better efficiency than silicon diodes,

due to a combination of lower forward voltage and

reduced recovery time.

It is important to select parts with a peak current rating

above the peak coil current and a continuous current

rating higher than the maximum output load current. It

is very important to consider the reverse leakage of the

diode when operating above 85°C. Excess leakage will

increase the power dissipation in the device and if close

to the load may create a thermal runaway condition.

The higher forward voltage and overshoot due to

reverse recovery time in silicon diodes will increase the

peak voltage on the SW output. If a silicon diode is

used, care should be taken to ensure that the total

voltage appearing on the SW pin including supply

ripple, does not exceed the specified maximum value.

The following web sites are useful when finding

alternatives: www.onsemi.com

Reducing output ripple

Peak to peak ripple current in the LED(s) can be

reduced, if required, by shunting a capacitor CLED

across the LED(s) as shown below:

PT4115PT4115

VIN CSN SW

DIM

GND

RS

L

D68uH

0.13Ω3W

LED

VIN

A value of 1uF will reduce the supply ripple current by

a factor three (approx.). Proportionally lower ripple can

be achieved with higher capacitor values. Note that the

capacitor will not affect operating frequency or

efficiency, but it will increase start-up delay and reduce

the frequency of dimming, by reducing the rate of rise

of LED voltage.

By adding this capacitor the current waveform through

the LED(s) changes from a triangular ramp to a more

sinusoidal version without altering the mean current

value.

Operation at low supply voltage

The internal regulator disables the drive to the switch

until the supply has risen above the startup threshold

(VUVLO). Above this threshold, the device will start to

operate. However, with the supply voltage below the

specified minimum value, the switch duty cycle will be

high and the device power dissipation will be at a

maximum. Care should be taken to avoid operating the

device under such conditions in the application, in

order to minimize the risk of exceeding the maximum

allowed die temperature. (See next section on thermal

considerations). The drive to the switch is turned off

when the supply voltage falls below the under-voltage

threshold (VUVLO-0.5V).

This prevents the switch working with excessive 'on'

resistance under conditions where the duty cycle is

high.

Thermal considerations

When operating the device at high ambient

temperatures, or when driving maximum load current,

care must be taken to avoid exceeding the package

power dissipation limits. The graph below gives details

for power derating. This assumes the device to be

mounted on a 25mm2 PCB with 1oz copper standing in

still air.




PT4115

Note that the device power dissipation will most often

be a maximum at minimum supply voltage. It will also

increase if the efficiency of the circuit is low. This may

result from the use of unsuitable coils, or excessive

parasitic output capacitance on the switch output. When

the application is limited by the internal power

dissipation of the device, the ESOP8 package is

recommended because of its enhanced power

dissipation ability.

Thermal compensation of output current

High luminance LEDs often need to be supplied with a

temperature compensated current in order to maintain

stable and reliable operation at all drive levels. The

LEDs are usually mounted remotely from the device

so，for this reason, the temperature coefficients of the

internal circuits for the PT4115 have been optimized to

minimize the change in output current when no

compensation is employed. If output current

compensation is required, it is possible to use an

external temperature sensing network - normally using

Negative Temperature Coefficient (NTC) thermistors

and/or diodes, mounted very close to the LED(s). The

output of the sensing network can be used to drive the

DIM pin in order to reduce output current with

increasing temperature.

Thermal shutdown protection

To ensure the reliability, the PT4115 is built with a

thermal shutdown (TSD) protection function. The TSD

protests the IC from over temperature (160). When

the chip temperature decreases (140), the IC recovers

again.

Layout considerations

Careful PCB layout is critical to achieve low switching

losses and stable operation. Use a multilayer board

whenever possible for better noise immunity. Minimize

ground noise by connecting high-current ground returns,

the input bypass-capacitor ground lead, and the

output-filter ground lead to a single point (star ground

configuration).

SW pin

The SW pin of the device is a fast switching node, so

PCB tracks should be kept as short as possible. To

minimize ground 'bounce', the ground pin of the device

should be soldered directly to the ground plane.

Coil and decoupling capacitors and current sense

resistor

It is particularly important to mount the coil and the

input decoupling capacitor as close to the device pins as

possible to minimize parasitic resistance and inductance,

which will degrade efficiency. It is also important to

minimize any track resistance in series with current

sense resistor RS. It’s best to connect VIN directly to

one end of RS and CSN directly to the opposite end of

RS with no other currents flowing in these tracks. It is

important that the cathode current of the Schottky diode

does not flow in a track between RS and VIN as this

may give an apparent higher measure of current than is

actual because of track resistance.




PT4115

TYPICAL APPLICATION CIRCUIT

PT4115PT4115

VIN CSN SW

DIM

GND

RS

L

CIN

VIN

D

100u

H

100uF

AC12-18V

DC6-30V

0.286Ω

LED

1W

Fig1 ：1W application

PT4115PT4115

VIN CSN SW

DIM

GND

RS

L

CIN

VIN

D 68uH

100uF

AC12-18V

DC6-30V

0.286Ω

LED

1W

Fig 2： 3W application




PT4115

TYPICAL APPLICATION CIRCUIT (Continued)

Fig 3 DEMO board for mass production




PT4115

PACKAGE INFORMATION

SOT89-5 Package

SYMBOL MILLIMETERS INCHES

MIN MAX MIN MAX

A 1.400 1.600 0.055 0.063

b 0.320 0.520 0.013 0.020

b1 0.360 0.560 0.014 0.022

c 0.350 0.440 0.014 0.017

D 4.400 4.600 0.173 0.181

D1 1.400. 1.800 0.055 0.071

E 2.300 2.600 0.091 0.102

E1 3.940 4.250 0.155 0.167

e 1.500 TYP. 0.060 TYP.

e1 2.900 3.100 0.114 0.122

L 0.900 1.100 0.035 0.043

D

D1

b1

be

e1

L

E1 E

A

c




PT4115

PACKAGE INFORMATION

ESOP-8 Package

SYMBOL DIMENSIONS IN MILLIMETERS DIMENSIONS IN INCHES

MIN MAX MIN MAX

A 1.350 1.750 0.053 0.069

A1 0.050 0.150 0.004 0.010

A2 1.350 1.550 0.053 0.061

b 0.330 0.510 0.013 0.020

c 0.170 0.250 0.006 0.010

D 4.700 5.100 0.185 0.200

D1 3.202 3.402 0.126 0.134

E 3.800 4.000 0.150 0.157

E1 5.800 6.200 0.228 0.244

E2 2.313 2.513 0.091 0.099

e 1.270(BSC) 0.050(BSC)

L 0.400 1.270 0.016 0.050

θ 0° 8° 0° 8°

Documents

490 Final Report COMPLETE With PDFs