This tutorial shows Saber applied to the modeling and simulation of a common AC/DC power converter topology. The automation available in the Saber environment allows the converter to be thoroughly verified and regression-tested over a broad range of operating conditions.

1. Alan Courtay
March 22, 2016
Quasi-resonant Flyback Converter Simulation
Saber Tutorial

2. © 2016 Synopsys, Inc. 2
Agenda
• Quasi-Resonant Flyback Converter (AN1326)
– Principles of Operation
– Simulation vs. Measurement
• Accurate Datasheet-Driven Modeling
– Controller Chip
– MOSFET
– Transformer
• Automated Verification
– EMI
– Loss / Efficiency

3. © 2016 Synopsys, Inc. 3
Vin: 50/60Hz, 88 to 264 Vac
Vout1: 105 V ± 5%
Iout1: 0.1 to 0.35 A
Vripple1: 1%
Vout2: 14 V ± 10%
Iout2: 0.1 to 1 A
Vripple2: 1%
L6565-Based 50W QR ZVS Flyback
Vout3: 5 V ± 5%
Iout3: 50 mA
Vripple3: <1%

4. © 2016 Synopsys, Inc. 4
Vin: 50/60Hz, 88 to 264 Vac
L6565-Based 50W QR ZVS Flyback
Power Stage
Vds
t
Currents
t
Vr
Vr
Llk&Cd
Lp&Cd
Ipeak
Secondary
Vin
Primary Demagnetization
Ton
Llk+Lp
Cd
Llk+Lp
Vout1: 105 V ± 5%
Iout1: 0.1 to 0.35 A
Vripple1: 1%
Vout2: 14 V ± 10%
Iout2: 0.1 to 1 A
Vripple2: 1%
Discontinuous Conduction Mode
Peak Current Mode Control
Vout3: 5 V ± 5%
Iout3: 50 mA
Vripple3: <1%

5. © 2016 Synopsys, Inc. 5
Vin: 50/60Hz, 88 to 264 Vac
L6565-Based 50W QR ZVS Flyback
Power Stage
Vds
t
Currents
t
Ipeak
Vin
Ton Toff
Valley
Switching
Vout1: 105 V ± 5%
Iout1: 0.1 to 0.35 A
Vripple1: 1%
Vout2: 14 V ± 10%
Iout2: 0.1 to 1 A
Vripple2: 1%
Vr
Vr
Vout3: 5 V ± 5%
Iout3: 50 mA
Vripple3: <1%

6. © 2016 Synopsys, Inc. 6
Vin: 50/60Hz, 88 to 264 Vac
L6565-Based 50W QR ZVS Flyback
Power Stage
Vds
t
Currents
t
Ipeak
Vin
Ton Toff
ZVS
Vr
Vin < Vr
Vout1: 105 V ± 5%
Iout1: 0.1 to 0.35 A
Vripple1: 1%
Vout2: 14 V ± 10%
Iout2: 0.1 to 1 A
Vripple2: 1%
Vout3: 5 V ± 5%
Iout3: 50 mA
Vripple3: <1%

7. © 2016 Synopsys, Inc. 7
Vin: 50/60Hz, 88 to 264 Vac
L6565-Based 50W QR ZVS Flyback
Power Stage
Vds
t
Currents
t
Ipeak
Vin
Ton Toff
Skip Cycle
Vout1: 105 V ± 5%
Iout1: 0.1 to 0.35 A
Vripple1: 1%
Vout2: 14 V ± 10%
Iout2: 0.1 to 1 A
Vripple2: 1%
Vout3: 5 V ± 5%
Iout3: 50 mA
Vripple3: <1%

8. © 2016 Synopsys, Inc. 8
RCD
Clamp
Output Voltage Regulation Feedback
Vin: 50/60Hz, 88 to 264 Vac
Vout1: 105 V ± 5%
Iout1: 0.1 to 0.35 A
Vripple1: 1%
Vout2: 14 V ± 10%
Iout2: 0.1 to 1 A
Vripple2: 1%
L6565-Based 50W QR ZVS Flyback
Power Stage
Vcc
start-up
self-supply
Vout3: 5 V ± 5%
Iout3: 50 mA
Vripple3: <1%

9. © 2016 Synopsys, Inc. 9
L6565-Based 50W QR ZVS Flyback

10. © 2016 Synopsys, Inc. 10
Agenda
• Quasi-Resonant Flyback Converter (AN1326)
– Principles of Operation
– Simulation vs. Measurement
• Accurate Datasheet-Driven Modeling
– Controller Chip
– MOSFET
– Transformer
• Automated Verification
– EMI
– Loss / Efficiency

11. © 2016 Synopsys, Inc. 11
Current Sense and Primary Voltage
Full Load, Vin = 100 V
4µs 4µs
1V
100V

12. © 2016 Synopsys, Inc. 12
Current Sense and Primary Voltage
Full Load, Vin = 380 V
2µs 2µs
1V
100V

13. © 2016 Synopsys, Inc. 13
Current Sense and Primary Voltage
Half Load, Vin = 100 V
4µs 4µs
1V
100V

14. © 2016 Synopsys, Inc. 14
Current Sense and Primary Voltage
Half Load, Vin = 380 V
2µs 2µs
0.5V
100V

15. © 2016 Synopsys, Inc. 15
Cycle Skipping / Frequency Foldback
Light Load, Vin = 300 V
5µs 5µs
0.5V
100V

16. © 2016 Synopsys, Inc. 16
Current Sense and Primary Voltage
Standby, Vin = 380 V
Burst Mode
100µs 100µs
0.5V
100V

17. © 2016 Synopsys, Inc. 17
Agenda
• Quasi-Resonant Flyback Converter (AN1326)
– Principles of Operation
– Simulation vs. Measurement
• Accurate Datasheet-Driven Modeling
– Controller Chip
– MOSFET
– Transformer
• Automated Verification
– EMI
– Loss / Efficiency

18. © 2016 Synopsys, Inc. 18
Modeling
Controller IC

19. © 2016 Synopsys, Inc. 19
Modeling
Controller IC

20. © 2016 Synopsys, Inc. 20
Modeling
Controller IC
Turn-on
Valley detection model
with StateAMS tool
Blanking time
model with TLU tool
Frequency foldback

21. © 2016 Synopsys, Inc. 21
Modeling
Controller IC
Turn-on
Turn-off
Line voltage feedforward
function implemented in MAST
Limits power capability
at high line voltage

22. © 2016 Synopsys, Inc. 22
Modeling
Power MOSFET

23. © 2016 Synopsys, Inc. 23
Modeling
Power MOSFET
• DC Characteristics
Characterized
Temperatures

24. © 2016 Synopsys, Inc. 24
Modeling
Power MOSFET
• DC Characteristics
• Interelectrode Capacitances

25. © 2016 Synopsys, Inc. 25
Modeling
Power MOSFET
• DC Characteristics
• Interelectrode Capacitances
• Gate Charge Characteristic

26. © 2016 Synopsys, Inc. 26
Modeling
Transformer

27. © 2016 Synopsys, Inc. 27
Modeling
Transformer
• Ferrite Core 3C85
– Hysteresis (major and minor BH loops)
– Frequency dependent losses (hysteresis
and eddy currents)

28. © 2016 Synopsys, Inc. 28
Modeling
Transformer
• Ferrite Core 3C85
– Hysteresis (major and minor BH loops)
– Frequency dependent losses (hysteresis
and eddy currents)

29. © 2016 Synopsys, Inc. 29
Modeling
Transformer
• Ferrite Core 3C85
– Hysteresis (major and minor BH loops)
– Frequency dependent losses (hysteresis
and eddy currents)

30. © 2016 Synopsys, Inc. 30
Modeling
Transformer
• Ferrite Core 3C85
– Hysteresis (major and minor BH loops)
– Frequency dependent losses (hysteresis
and eddy currents)
• Core geometry
– Air gap
– Lamination

31. © 2016 Synopsys, Inc. 31
Modeling
Transformer
• Ferrite Core 3C85
– Hysteresis (major and minor BH loops)
– Frequency dependent losses (hysteresis
and eddy currents)
• Core geometry
– Air gap
– Lamination
• Windings (Cauer - 1D Model)
– Flux leakage
– Frequency dependent loss (skin and
proximity effects)
– Winding capacitances

32. © 2016 Synopsys, Inc. 32
Modeling
Transformer
• Ferrite Core 3C85
– Hysteresis (major and minor BH loops)
– Frequency dependent losses (hysteresis
and eddy currents)
• Core geometry
– Air gap
– Lamination
• Windings (Cauer - 1D Model)
– Flux leakage
– Frequency dependent loss (skin and
proximity effects)
– Winding capacitances

33. © 2016 Synopsys, Inc. 33
Agenda
• Quasi-Resonant Flyback Converter (AN1326)
– Principles of Operation
– Simulation vs. Measurement
• Accurate Datasheet-Driven Modeling
– Controller Chip
– MOSFET
– Transformer
• Automated Verification
– EMI
– Loss / Efficiency

34. © 2016 Synopsys, Inc. 34

35. © 2016 Synopsys, Inc. 35
LISN

36. © 2016 Synopsys, Inc. 36

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39. © 2016 Synopsys, Inc. 39
Experiment Editor Basic Tasks

40. © 2016 Synopsys, Inc. 40

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Parallel
Computing

42. © 2016 Synopsys, Inc. 42
Loss breakdown
report

43. © 2016 Synopsys, Inc. 43
Converter
efficiency

44. © 2016 Synopsys, Inc. 44
Most dissipative
components

45. © 2016 Synopsys, Inc. 45
Conduction Losses Switching Losses

46. © 2016 Synopsys, Inc. 46
Conduction Losses Switching Losses
Rac = 50kΩ added across primary
to account for air gap fringing field
losses
NTC thermistor
adjusted to 2.5Ω

47. © 2016 Synopsys, Inc. 47
Rac = 50kΩ added across primary
to account for air gap fringing field
losses
NTC thermistor
adjusted to 2.5Ω

48. © 2016 Synopsys, Inc. 48
Conclusion
• High fidelity models characterized from datasheets
• Automated design verification / regression testing over broad
operating conditions
– Experiment Analyzer
– Fault Injection
– Worst Case Analysis / Extreme Value Analysis
– Statistical variations (Monte Carlo)
• Scalable solution
– Capacity for large designs (network of power converters)
– User or site (company wide) model library management
– Distributed/grid iterative analysis (parametric Vary, Monte-Carlo,
Worst-Case Analysis, Fault)

49. © 2016 Synopsys, Inc. 49
Thank You
• Flyback design available on Synopsys Forum
• Improved IGBT Tool in 2016.03
Thank you to Sophia LI, Min ZHANG and Balaji EMANDI for their contributions.
Special thanks to Claudio ADRAGNA and Giovanni GRITTI from ST for their valuable feedback.