Coil and PCB for Inductive Noise Solution for DC-DC …register.ansys.com.cn/.../emi/document/Coil_PCB_Noise_UGM_Final_2… · Coil and PCB for Inductive Noise Solution for DC-DC

© 2011 ANSYS, Inc. 1

Coil and PCB for Inductive Noise Solution for DC-DC Converter

2013.1.8

ANSYS Japan K.K.

Takahiro Koga


• Motivation and Summary

• Solutions

1. Electromagnetic Analysis 1. Coil : Magnetic Saturation (Maxwell)

2. PCB : Magnetic Coupling (Q3D Extractor)

3. Coil and PCB : Magnetic Coupling (Maxwell)

2. Circuit Simulation 1. Easy to Study with simple equivalent circuit (Simplorer)

2. Integrated System Simulation with FEA models (Simplorer)

• Conclusion

• Appendix: How about Harmonic Noise?

Agenda: Coil and PCB for Inductive Noise Solution


• A Coil on the PCB is often doubted as noise source, because it has “Gap” and “Leakage Flux” for Ground Plane as Inductive noise..?

Motivation and Summary

Coil and PCB (Real Model for DC-DC) Coil and Simple PCB

(Virtual Test Model)


• What/How is the critical source of conducting noise on my power supply PCB ?

Motivation and Summary

Coil and PCB (Real Model for DC-DC) Coil and Simple PCB

(Virtual Test Model)


• Electromagnetics : Maxwell 3D

• Electromagnetics : Q3D Extractor

• Circuit : Simplorer

• Option (for Maxwell, Q3D Extractor)

ALinks for MCAD

Optimetrics

HPC Pack

Suite ANSYS Products


• Inductance vs. Input Current

• Magnetostatic

• Specification Max. Current：10A

• 1A ~ 10A

Sim. 1-1 Coil, Magnetic Nonliear Saturation (Maxwell)

Model

Excitation(Current) Setting


• Result: Inductance vs. Input Current

Under the spec current(~10A), Not saturated inductance value.

Input Current to 50A

Sim. 1-1 Coil, Magnetic Nonlinear Saturation (Maxwell)

0.00 10.00 20.00 30.00 40.00 50.00Current [A]

0.00

5.00

10.00

15.00

20.00

25.00

30.00

Ma

trix

1.L

(Cu

rre

nt1

,Cu

rre

nt1

) [u

H]

2nd_Coil_OnlyL vs Current

Curve Info

Matrix1.L(Current1,Current1)Setup1 : LastAdaptive

Inductance dropped over 40A

Inductance vs. Input Current

21uH Flat


• Result: Field Plot Mag_B on the Core

Not magnetic saturated -> Suitable core design


Max. 0.4[T]

5A

10A

Core’s BH Curve


• Additional Test: Field Plot Mag_B on the Core over 20A

Start to saturate( 0.4T～） over 20A , but still Inductance is sustained.


Max. 0.4[T]

20A 40A 50A

© 2011 ANSYS, Inc. 10

• Can be linear up to 10A ?

Yes, possible to be linear up to 30A for circuit simulation.


0.00 10.00 20.00 30.00 40.00 50.00Current [A]

0.00

5.00

10.00

15.00

20.00

25.00

30.00

Ma

trix

1.L

(Cu

rre

nt1

,Cu

rre

nt1

) [u

H]

0.00

5.00

10.00

15.00

20.00

25.00

30.00

Lin

ea

r [u

]

2nd_Coil_OnlyL vs Current

Curve Info


LinearSetup1 : LastAdaptive

μr = 3000 Constant Nonlinear BH Curve

Core’s BH Curve

μr = 3000

Inductance vs. Input Current

© 2011 ANSYS, Inc. 11

• Self/Mutual Inductance(L,M), Magnetic Coupling Coefficient(k)

• DCRL, ACRL(1kHz～2MHz)

• Reduced Matrix PWR1 and PWR2 are merged into one , then evaluate L, M, k with GND

Sim. 1-2 PCB, Coupling PWR - GND Lines (Q3D Extractor)

GND

PWR1

PWR2

PWR

LGND M M LPWR

© 2011 ANSYS, Inc. 12

• Result: Self Inductance(L), Mutual Inductance(M) vs. Frequency

M: 44nH Flat


1.00 10.00 100.00 1000.00 10000.00Freq [kHz]

0.00

25.00

50.00

75.00

100.00

125.00

150.00

Y1

[n

H]

Q3DDesign1L. M vs Freq

Curve Info

ACL(GND:GND_Source,GND:GND_Source)

ACL(GND:GND_Source,PWR:PWR1_Source)

ACL(PWR:PWR1_Source,PWR:PWR1_Source)

Mutual Inductance(M)

Self Inductance(L) LGND

LPWR

M= 44nH

© 2011 ANSYS, Inc. 13

• Result: Magnetic Coupling Coefficient(k) vs. Frequency

k: 0.35 Flat


0.00 0.01 0.10 1.00 10.00Freq [MHz]

0.00

0.20

0.40

0.60

0.80

1.00

k

Q3DDesign1k vs Freq

Curve Info

kSetup1 : Sw eep1

k= 0.35

© 2011 ANSYS, Inc. 14

• Additional Test

Swept GND Position


-20.00 -15.00 -10.00 -5.00 0.00 5.00 10.00 15.00 20.00move_x [mm]

0.00

0.20

0.40

0.60

0.80

1.00

kQ3DDesign1k vs GND Position

Curve Info

kSetup1 : Sw eep1Freq='0.0001GHz'

k: 0.26 ~ 0.58

Default Position

-20mm +18mm

© 2011 ANSYS, Inc. 15

• Self/Mutual Inductance(L,M), Magnetic Coupling Coefficient(k)

• Magnetostatics

• 1A～20A

Sim. 1-3 Coil and PCB, Coupling Coil - GND Lines (Maxwell)

Model

Top of view

GND

Coil

© 2011 ANSYS, Inc. 16

• Result：Mutual Inductance(M), Magnetic Coupling Coefficent(k) at 1A~20A

M: 1.1nH～2.1nH

k: 0.0013～0.0007

Very small value compared with PWR-GND lines coupling * Ref. slide 18-19


0.00 5.00 10.00 15.00 20.00Current [A]

0.00

2.00

4.00

6.00

8.00

10.00

Ma

trix

1.L

(Cu

rre

nt1

,Cu

rre

nt3

) [n

H]

4th_Coil_GNDM vs Current

Curve Info


M vs. input Current k vs. input current

M= 1.1nH～2.1nH

0.00 5.00 10.00 15.00 20.00Current [A]

0.000

0.002

0.004

0.006

0.008

0.010

Ma

trix

1.C

plC

oe

f(C

urr

en

t1,C

urr

en

t3)

4th_Coil_GNDk vs Current

Curve Info

Matrix1.CplCoef(Current1,Current3)Setup1 : LastAdaptive

k= 0.0007～0.0013

© 2011 ANSYS, Inc. 17

• Additional Test

Swept GND Position


-20.00 -15.00 -10.00 -5.00 0.00 5.00 10.00 15.00 20.00move_x [mm]

-0.0010

-0.0005

0.0000

0.0005

0.0010

Ma

trix

1.C

plC

oe

f(C

urr

en

t1,C

urr

en

t3)

5th_Coil_GND_Lineark vs GND Position

Curve Info

Matrix1.CplCoef(Current1,Current3)Setup1 : LastAdaptive

Default Position

-20mm +18mm

k= 0.00078～-0.00028

© 2011 ANSYS, Inc. 18

• Equivalent circuit with extracted parameters(R,L,k)

• Input switching voltage to the equivalent circuit model and analyzing inductive current at GND line (as inductive noise)

• Motivation:

Which coupling factor is dominant for noise?

Sim. 2-1 Easy to Study with simple equivalent circuit (Simplorer)

Model

Switching Freq. 100kHz

© 2011 ANSYS, Inc. 19

• Easy to Study Equivalent Circuit

Equivalent Circuit with extracted parameters


Easy to Study Equivalent Circuit

GND

PWR1 PWR2

Coil

M: GND – PW1 M: GND – PWR2 M: GND - Coil

Coil

PWR2

PWR1

GND

© 2011 ANSYS, Inc. 20

• Result #1: Waveform Coil(Power line) Current and Induced Current at GND line

Max 0.84A in the GND Line @ Max. 10A in the Power Line


Current at Coil, PWR line

Current at GND line (Inductive Noise)

100.00 150.00 200.00 250.00 300.00 350.00 400.00Time [us]

-2.00

0.00

2.00

4.00

6.00

8.00

10.00

Y1

[A

]

1st_AllCurrent

Curve Info max rms

R_GND.ITR

0.8394 0.5014

R_PWR1.ITR

9.8561 7.3096

© 2011 ANSYS, Inc. 21

• Result #2: What happens if GND is floated?

No current induced (No noise)


100.00 150.00 200.00 250.00 300.00 350.00 400.00Time [us]

-2.00

0.00

2.00

4.00

6.00

8.00

10.00

Y1

[A

]

2nd_GND_FloatCurrent

Curve Info max rms

R_GND.ITR

0.0000 0.0000

R_PWR1.ITR

9.8545 7.3094

Connect High impedance (1Mohm) to GND



© 2011 ANSYS, Inc. 22

• Each Self/Mutual Inductance values

• GND-Coil mutual inductance value is very smaller than others -> How influence is this for Noise?


47.5nH 42.5nH

143.9nH

21240nH

22.0nH 22.0nH 1.24nH

© 2011 ANSYS, Inc. 23

• Result #2: What happens if M between Coil and GND was neglected?

No change in Inductive Noise


100.00 150.00 200.00 250.00 300.00 350.00 400.00Time [us]

-2.00

0.00

2.00

4.00

6.00

8.00

10.00

Y1

[A

]

3rd_EVB_couplingCurrent

Curve Info max rms

R_GND.ITR

0.8163 0.4876

R_PWR1.ITR

9.8560 7.3096



© 2011 ANSYS, Inc. 24

• Result #3: What happens if M between PWR1,2 and GND were neglected?

Inductive Noise significantly reduced


100.00 150.00 200.00 250.00 300.00 350.00 400.00Time [us]

-2.00

0.00

2.00

4.00

6.00

8.00

10.00

Y1

[A

]

4th_Coil_CouplingCurrent

Curve Info max rms

R_GND.ITR

0.0230 0.0138

R_PWR1.ITR

9.8545 7.3094



© 2011 ANSYS, Inc. 25

• Result #1 - #3: FFT on GND Line current


#1: Original #2: M(Coil-GND) is neglected #3: M(PWR-GND) is neglected

© 2011 ANSYS, Inc. 26

• Maxwell and Q3D models brought into Simplorer

• Previous analysis confirmed the coupling between the Coil and GND Line can be neglected

Sim. 2-2 Integrated System Simulation with FEA models (Simplorer)

Integrated model

Q3D Extractor

Maxwell

© 2011 ANSYS, Inc. 27

• Result: Waveform and FFT Coil(Power line) Current and Induced Current at GND line

Sim. 2-2 Integrated System Simulation with FEA models (Simplorer)

100.00 150.00 200.00 250.00 300.00 350.00 400.00Time [us]

-2.00

0.00

2.00

4.00

6.00

8.00

10.00

Y1

[A

]

5th_Mxwl_Q3D_CouplingCurrent

Curve Info max rms

AM1.I 1.6091 1.0081

R_Coil.I 9.8136 7.2690

0.00 0.01 0.10 1.00 10.00Spectrum [MHz]

1.00E-006

1.00E-005

1.00E-004

1.00E-003

1.00E-002

1.00E-001

1.00E+000

ma

g(A

M1

.I)

[A]

5th_Mxwl_Q3D_CouplingFFT GND Current

Curve Info

mag(AM1.I)TR



© 2011 ANSYS, Inc. 28

• Effect of the leakage flux from the coil on the PCB traces is evaluated by simulation

• Possible three factors of the noise source are investigated

• Noise due to the crosstalk coupling among the traces on the PCB is dominant , while crosstalk between the coil and the traces is negligible

• ANSYS can provide the effective noise evaluation solution by EM-Circuit coupled SYSTEM simulation

Conclusion

© 2011 ANSYS, Inc. 29

• You can step up PCB model(Q3D Extractor) from virtual test model to Real model

Step Up Solution

Can clear the magnetic coupling relation between coil and PCB with Maxwell 3D, Q3D Extractor and Simplorer

Documents

Coil and PCB for Inductive Noise Solution for DC-DC …register.ansys.com.cn/.../emi/document/Coil_PCB_Noise_UGM_Final_2… · Coil and PCB for Inductive Noise Solution for DC-DC