Power Supply Solutionsfor small/medium/big size

LCD-PDP/TV

Content

Classical Approach:60W SMPS (<20”)200W SMPS (up to 30-32”)

Resonant Approach:70W SMPS (<20”)180W SMPS (up to 30”)500W SMPS (up to 50”LCD-TV, 42” PDP-TV

60W LCD-TV Power Supply: Block Diagram

Vac

+12V

Feedback

Advanced PWM

Controller

Power Supply UnitEMI filter&

Bridge Rectifier

•Operation close to the boundary between CCM and DCM: variable operating frequency

•Zero Voltage/Zero Current Switching at turn-on achievable

•Less EMI generated

•Variable frequency spreads spectrum

•Stand-By function put into optional

Accurate OCP and OVP circuit are building in the simple can be optional.

5A12VRemarksCurrent

Total Output Power: 60W

VoutSingle Output Voltage (Vout): Wide Input Voltage Range: 90-265VAC

60W LCD-TV Power Supply: Specifications

L6565

60W LCD-TV Power Supply: Schematic

60W LCD-TV Power Supply:Testing Report

87.4%264V

87.0%240V

83.2%100V

81.7%90V

No LoadStand By

Input PowerFL Eff.Input Voltage

Testing Results

0ANo Load

0.0416A (0.5W)Stand By

5AFull Load (FL)

12VOuput

Test Loading

Loading efficiency

A 60W LCD-TV Power Supply

L6565: Quasi-Resonant SMPS controller

• Current Mode Quasi-Resonant PWM controller

• Micropower Start-up Current (40µA typ.)

• Low Quiescent Current (3mA typ.)• ZCD input for QR operation/external

synchronization• Frequency Foldback function• Line Voltage Feedforward function• Pulse-by-pulse overcurrent

protection• 2nd overcurrent level with Hiccup-

mode operation• Disable function• Internal RC filter on Current Sense• Package: Minidip and SO8

QR Conversion:Quasi-Resonant Concept

Vin

Cin

Lm

Llk

Cd

VoutLp

Ls

VDS

ZVS condition: Vin ≤ VR

Operation close to the boundary between CCM and DCM: variable operating frequencyZero Voltage/Zero Current Switching at turn-on achievableLess EMI generatedVariable frequency spreads spectrum

Lp & Cd

Llk & Cd

Vin

t

VDS

VR

Ip

Pri Sec

TFW

T = 1/ fsw

TON Tv

IPKp

IPKs

ZVSNO ZVS!

VDS @ Vin2 >Vin

Vin2

Ip @ Vin2 >Vin

Is @ Vin2 >Vin

EMC filter &Bridge Rectifier

DC DCconv.

+5V

+24V

+12V

Feedback

PFC+PWM+AuxL6562+L5991

+L6590

+5V standby

Vac

200W LCD-TV Power Supply: Block Diagram

Power Supply Unit•PFC200W critical control mode with ZCD function for a cost-effective application

•Main Converter200W FlybackConverter for middle size LCD-PDP/TV application

•Standby10W Flybackconverter with build-in mosfet PWM controller and circuit to switch off

200W LCD-TV Power Supply:Specifications

5V output use DC-DC converter which can be put in optional.

6A3A2A2A

24V12V5V

5Vsb

RemarksCurrent

Total output Power : 200W

VoutMulti Output Voltages (Vout): Wide Input voltage range: 90-265VAC

200W LCD-TV Power Supply: Schematic

Advanced PWM ControllerL6562+L5991+L6590

L5973D

200W LCD-TV Power Supply: Testing Report

87.5%264V

86.8%220V

84.3%120V

81.6%90V

No LoadStand byInput PowerFL Eff.Input voltage

Testing result0000No Load

0.1000Stand by

2236Full load (FL)

5VSB5V12V24VOutputs

Test Loading

Loading efficiency

200W LCD-TV Power Supply

L6562 - Power Factor Corrector

• TRANSITION-MODE • PROPRIETARY MULTIPLIER DESIGN FOR MINIMUM THD OF AC INPUT CURRENT• LOW (<4 mA) QUIESCENT CURRENT• ON-CHIP FILTER ON CURRENT SENSE • 1% (@ Tj = 25 °C) INTERNAL REFERENCE VOLTAGE• -600/+800mA TOTEM POLE GATE DRIVER WITH UVLO PULL-DOWN AND VOLTAGE CLAMP

L5991/A Primary PWM Controller

•CM 1MHz PWM Controller•Low Start-Up Current (<150 µA)•Low Quiescent Current (7mA typ.)•Standby function•Programmable 'Hiccup‘ ModeOvercurrent Protection•IN/OUT Synchronization•Precise Duty Cycle ControlLatched•Shutdown/Overvoltage Protection•Programmable Soft-Start•Internal 100 ns Leading EdgeBlanking on Current Sense•Package: DIP-16/SO-16

L6590/A Fully Integrated Power Supply

L6590 - Standby Function

Contact Persons in Shenzhen MMX Technical Center

Application Engineer 23318601郭加总GuoTom

Senior Application Engineer 13692 222 12823348601郭青山GuoSam

Senior Application Engineer 23278601陈治国ChenRoy

Application Engineer 23118601彭 超PengChaoT/C Deputy Manager9752 127513602 616 66223068601方弘均BANGHG

A&P Lab, Industrial and Power TeamFax number:8601-2300Operator: 8601-2000

HONG KONGCHINA

FUNCTION / REMARKS

MOBILETELEPHONE

NO.CHINESE

NAMENAME

A new approach:Half Bridge Resonant topology in LCD TV with ST L6598

controller

LCD TV power supply configuration

AC Filter +Rectifier PFC stage DC-DC stage

DC-DC stage

L

N

Auxiliary Power

Main Power400Vdc Inverter

Audio

TunerLogic IC

5V

24V

18V9V

5V,3.3V

uP

PFC stage in Main Power

Po of PFC

23” LCD TV

120W

26” LCDTV

160W

30” LCD TV

180W 220W 300W 460W 600W

40” LCD TV

50” LCD TV

42” PDPTV

250W

150W 400W

250W

L6561 or L6562 in Transition Mode

L6562 with Fixed Off-Time Control

L4981 in Continuous Conduction Mode

DC-DC stage in main power

Step down converter

Step down converter

L6598

L5973, L4973

LM317

400Vdc Inverter

Tuner

Half BridgeResonantController

+

Synchronousrectification

Half Bridge Resonant Converter24V

18V

5V,3.3V

9V

Audio

L6997, L6910Step down converter

Logic IC

Power rating for inverter, audio, tuner,and logic IC in LCD TV

Inverter : 30” - 12V/10A, 20V/6A, 24V/5A 42” - 24V/10A50” - 120V/3A

Audio : 12V/2.5A ( class D )18V/2A ( class AB )

Tuner : 8V, 9V, 30V, 33V

Logic IC : 5V/4A, 3.3V/3A

L6598

With high efficiency, low EMI, cost effectiveness and high power density, it is a good solution for built-in LCD TV power supplies

Half Bridge Resonant Controller

L6598 Main Features• Resonant controller up to 400KHz• High voltage rail up to 600V• Low start up current ( < 250uA )• Low quiescent current ( <2mA )• Latched / non latched device disable• 50% duty cycle half bridge driver• Programmable soft start• Integrated bootstrap diode• 350nS dead time• OP AMP for further protections

( Brown out, OTP …..)• Package : DIP16 / SO16

L6598 internal block diagramInternal bootstrap diode

Latch

Non latch

L6598 transformer topologies

For low output voltageand high output current

For high output voltageand low output current

Remark : a current doubler circuit can also be used to get a small ripple at the output

Benefits of L6598-based power supply

• Reduction of switching losses because of zero voltage switching at turn-on of power MOS

• Reduced current in the half bridge power MOS• Reduced RMS current in secondary diodes• Reduced EMI filter dimension and cost• Reduced core loss• Reduced size and COST

How to achieve ZVS in series resonant converter

Q2

Q1

DQ2

DQ1

L1

Q2

Q1

L1LOAD

T

LM

D1

D2

COUT

C1

C2

C1

C2

PFC output (+VBUS)

DQ2

DQ1

CQ2 CPIN

IL1

IQ1

IQ2

CQ1

G G

ICpin

LM N1

N2

N2

PFC output (+VBUS)

. Resonant topology

Q1

Q2

“G”

IQ2

IQ1

IL1

IDT0 T1T8

VC1

T2

ICpin

T3 T4 T5

T6

T7 T8

Diode current

D2 D1

VIN*D

D1

+VBUS

Diagram of 70W demo board with L6598

Half bridge resonant controller, L6598

PFC controller, L6561

Voltage and current controller, TSM`103

Evaluation result of 70W ( 18V/3.8A) demo board ( L6561 + L6598 )

HalfHalfHalfHalfFullFullFullFullHalfFull

Load

88.4%35.64W2A17.82V40.3W255Vac88.4%35.64W2A17.82V40.3W220Vac

88%35.64W2A17.82V40.5W110Vac86.93%35.64W2A17.82V41W88Vac

91.%67.64W3.8A17.8V74.4W255Vac90.5%67.64W3.8A17.8V74.7W220Vac88.6%67.64W3.8A17.8V76.35W110Vac87.3%67.64W3.8A17.8V77.5W88Vac91.3 %35.6W2A17.8V39W400Vdc93.9 %67.64W3.8A17.8V72W400VdcEffPoIoVoPiVin

Highefficiency

Diagram of 180W demo board with L6598

Input Voltage: 370V to 420V (PFC output)Output : 110V/1.2A, 24V/2AOutput power : 180W

Efficiency of 180W demo board with L6598

Max Efficiency is 95% at the maximum output power of 180W

Pout : 180W

500W demo board for LCD-PDP/TV power supplies

The demoboard is now under development andit will be available in Nov 2004

PFC stage( L4981B )

PWM stage( L6598 )

Aux. stage( L6590A )

L

N

Universal( 88 – 264 Vac ) 12V/7A

5V_aux/2A

120V/3.5A

Brown out

Overall Efficiency is estimated at abt. 91%

References• Documents1. L6598 datasheet , February 20022. AN1300, Application Note, L6598 based 12V/3A

resonant application, October 20003. AN1660, Application Note, ZVS resonant converter

for consumer application using L6598 IC, March 20034. AN1673, Application Note, L6598; off line controller for

resonant converter, June 20035. AN 658, Application Note, resonant converter topology

1. 70W ( 18V/3.8A ) demo board with L6561 and L6598

• Hardware