ST AN3212 Application note 3.5 W to 7 W high power factor offline LED driver based on VIPer devices

Summary

Designed for electrical engineers, this comprehensive application note details the development of high power factor offline LED drivers (3.5W to 7W) using VIPer devices. The manual guides users through advanced circuit design principles, focusing on achieving non-electrolytic configurations by replacing bulk capacitors with smaller ceramic components. It provides detailed technical coverage, including initial setup, circuit descriptions, performance measurements comparing capacitor types, waveforms, and complete electrical diagrams for reliable LED module integration.

Figure 1. EVLVIP27-7WLED VIPer27 LED driver module
1 Main characteristics
- 1.1 Initial configuration
  - Figure 2. Initial configuration
- 1.2 Requirements
2 Circuit description
- 2.1 Primary side
  - Figure 3. Primary side schematic
  - Figure 4. IDlim vs Rlim - VIPer17
  - Figure 5. IDlim vs Rlim - VIPer27
  - Figure 6. No feedback on FB pin
  - Figure 7. Feedback on FB pin
  - Figure 8. Feedback voltage V_fb vs. VAC and Vout
- 2.2 Secondary side
  - Figure 9. Secondary side equivalent schematic
- 2.3 Circuit variants
  - Table 1. Changes
3 Waveforms
- 3.1 Input
  - Figure 10. V_drain, I_drain at Vin= 75 V
  - Figure 11. V_drain, I_drain at Vin= 100 V
  - Figure 12. V_drain, I_drain at Vin= 120 V
  - Figure 13. V_drain, I_drain at Vin= 162 V
  - Figure 14. V_drain, I_drain at Vin= 254 V
  - Figure 15. V_drain, I_drain at Vin= 325 V
  - Figure 16. V_drain, I_drain at Vin= 391 V
  - Figure 17. V_drain, I_drain at Vin= 50 V
  - Figure 18. Vin and Iin at Vin = 230 VAC
  - Figure 19. Vin and Iin at Vin = 115 VAC
- 3.2 Output
  - Figure 20. V_out, I_out at Vin = 230 VAC, no El_cap
  - Figure 21. V_out, I_out at Vin = 115 VAC, no El_cap
  - Figure 22. V_out, I_out at Vin = 230 VAC, 1000 µF El_cap
  - Figure 23. V_out, I_out at Vin = 115 VAC, 1000 µF El_cap
- 3.3 Startup sequence
  - Figure 24. Startup sequence at Vin = 230 VAC, no El_cap
  - Figure 25. Startup sequence at Vin = 115 VAC, no El_cap
  - Figure 26. Startup sequence at Vin = 230 VAC, 1000 µF El_cap
  - Figure 27. Startup sequence at Vin = 115 VAC, 1000 µF El_cap
- 3.4 Short-circuit protection
  - Figure 28. Short-circuit protection
  - Figure 29. Short circuit application
  - Figure 30. Short circuit removal
- 3.5 Open circuit protection
  - Figure 31. Open circuit protection Vin = 277 VAC
  - Figure 32. Open circuit protection Vin = 90 VAC
  - Figure 33. Open circuit application
  - Figure 34. Open circuit removal
4 Measurements
- Figure 35. Test setup
- 4.1 7.0 W NO EL_CAP configuration
  - Figure 36. NO_El_Cap output voltage (average)
  - Figure 37. NO_El_Cap output current (average)
  - Figure 38. NO_El_Cap output current (peak)
  - Figure 39. NO_El_Cap output power
  - Figure 40. NO_El_Cap efficiency
  - Figure 41. NO_El_Cap power factor
- 4.2 7.0 W EL_CAP configuration
  - Figure 42. 1000 µF output voltage (average)
  - Figure 43. 1000 µF output current (average)
  - Figure 44. 1000 µF output current (peak)
  - Figure 45. 1000 µF output power
  - Figure 46. 1000 µF efficiency
  - Figure 47. 1000 µF power factor
- 4.3 EMI filter
  - Figure 48. EMI (PI filter) 230 VAC
  - Figure 49. EMI (PI filter) 115 VAC
  - Figure 50. EMI (L + PI filter) 230 VAC
  - Figure 51. EMI (L + PI filter) 115 VAC
- 4.4 Thermal maps
  - Figure 52. Thermal map at 90 VAC
  - Figure 53. Thermal map at 115 VAC
  - Figure 54. Thermal map at 230 VAC
  - Figure 55. Thermal map at 277 VAC
  - Table 2. Components max. temperature
5 Electrical diagram
- Figure 56. Electrical diagram
6 BOM list
- Table 3. BOM 7.0 W version
7 7 W transformer specifications
- 7.1 Mechanical specifications
  - Figure 57. Coil former mechanical drawing
  - Figure 58. Transformer assembly
- 7.2 Electrical specifications
  - Figure 59. Transformer electrical drawing
  - Table 4. Transformer winding data
8 Revision history
- Table 5. Document revision history

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AN3212

Application note

3.5 W to 7 W high power factor offline LED driver

based on VIPer devices

Introduction The driving idea behind this application note is to exploit the possibility of implementing an LED power supply module characterized by a high power factor, based on devices from the VIPer family in flyback configuration and with a TSM1052 as a constant current controller. The other key point is to avoid using high voltage electrolytic capacitors, evaluate the influence of the output bulk electrolytic capacitor on overall performance, and consider its replacement with much smaller ceramic components, eventually implementing a non electrolytic configuration. The EVLVIP27-7WLED demonstration board has been designed as a platform to perform this evaluation.

Figure 1. EVLVIP27-7WLED VIPer27 LED driver module

October 2010 Doc ID 17427 Rev 1 1/35

www.st.com

Page Summary Contents For ST AN3212 Application note 3.5 W to 7 W high power factor offline LED driver based on VIPer devices

Page 1 AN3212 Application note 3.5 W to 7 W high power factor offline LED driver based on VIPer devices Introduction The driving idea behind this application note is to exploit the possibility of implementin...

Page 2 Contents AN3212 Contents Main characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1 Initial configuration . . . . . . . . . . . . . . . . . . . . . . ...

Page 3 AN3212 List of figures List of figures Figure 1. EVLVIP27-7WLED VIPer27 LED driver module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Figure 2. Initial configuration . . . . ....

Page 4 List of figures AN3212 Figure 49. EMI (PI filter) 115 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Figure 50. EMI (L + PI filter) 230 ...

Page 5 AN3212 Main characteristics 1 Main characteristics 1.1 Initial configuration Several demonstration boards already exist which accept the mains input voltage, wide or local voltage range, and generate ...

Page 6 Circuit description AN3212 2 Circuit description 2.1 Primary side In order to keep the part count to a minimum, the primary side of the converter is based on a device from the VIPer family, a VIPer17 ...

Page 7 AN3212 Circuit description Care should be taken in designing the EMI filter due to the constraints indicated above. In Section 4: Measurements two versions are presented, with their different response...

Page 8 Circuit description AN3212 Figure 6 and 7 show the results of a simulation which represent the behavior of the circuit. Figure 6 is in the case of no feedback on the FB pin: only Vin is applied to the...

Page 9 AN3212 Circuit description Reducing its value increases the influence of V_fb, obtaining a better control of the output current even at the extreme mains and load values; on the other hand, increasing...

Page 10 Circuit description AN3212 Looking at the component values, it can be noted that: The time constant of the voltage op_amp is quite short (R9 = 0 Ω, C10 = 560 p F); this is because the circuit has to r...

Page 11 AN3212 Circuit description 2.3 Circuit variants Up to now the “basic” 7 W configuration has been referenced, but as indicated in the introduction to the document, the goal was also to investigate the ...

Page 12 Waveforms AN3212 3 Waveforms To take a look at the behavior of the board, the 7 W configuration has been selected and analyzed in the main characteristic conditions, capturing the relevant signals. 3....

Page 13 AN3212 Waveforms Figure 14. V_drain, I_drain at Vin= 254 V Figure 15. V_drain, I_drain at Vin= 325 V CH1 (brown)=Vdrain, CH3 (red)= Vout, CH1 (brown)=Vdrain, CH3 (red)= Vout, CH4 (green)= Idrain CH4 (...

Page 14 Waveforms AN3212 And to give an idea of the AC input voltage and current, Figure 18 and 19 show the plot of these waveforms. Figure 18. Vin and Iin at Vin = 230 VAC Figure 19. Vin and Iin at Vin = 115...

Page 15 AN3212 Waveforms With an output electrolytic capacitor of 1000 µF: Figure 22. V_out, I_out at Vin = 230 VAC, Figure 23. V_out, I_out at Vin = 115 VAC, 1000 µF El_cap 1000 µF El_cap CH1 (brown)=Vdrain,...

Page 16 Waveforms AN3212 Figure 26. Startup sequence at Vin = 230 VAC, Figure 27. Startup sequence at Vin = 115 VAC, 1000 µF El_cap 1000 µF El_cap CH1 (brown)=Iout CH3 (blue)= Vfb CH1 (brown)=Iout CH3 (blue)=...

Page 17 AN3212 Waveforms Figure 28. Short-circuit protection CH1 (brown)=Iout CH2 (blue)=Vout CH3 (red)=Vfb CH4 (green)=Vdd As the most severe condition appears at the highest input voltage, the snapshot is t...

Page 18 Waveforms AN3212 3.5 Open circuit protection As already indicated, the TSM1052 in the secondary section contains an op amp that senses the output, and in the case of overvoltage, drives the optocouple...

Page 19 AN3212 Waveforms Figure 33. Open circuit application Figure 34. Open circuit removal CH1 (brown)=Vdrain CH4 (green)=Iout CH1 (brown)=Vdrain CH4 (green)=Iout CH3 (red)=Vout CH3 (red)=Vout Doc ID 17427 ...

Page 20 Measurements AN3212 4 Measurements For all the board configurations, a common test setup was defined with: A HP6812B programmable AC mains voltage source A Yokogawa WT210 wattmeter to measure input vo...

Page 21 AN3212 Measurements This approach is correct whenever these values are constant, but in this application, due to the high ripple present, especially if no electrolytic capacitor is employed, these wav...

Page 22 Measurements AN3212 Figure 38. NO_El_Cap output current (peak) Figure 39. NO_El_Cap output power 22/35 Doc ID 17427 Rev 1

Page 23 AN3212 Measurements Figure 40. NO_El_Cap efficiency Figure 41. NO_El_Cap power factor Doc ID 17427 Rev 1 23/35

Page 24 Measurements AN3212 4.2 7.0 W EL_CAP configuration The following measurements were taken with a 1000 µF electrolytic capacitor connected to the module output. Figure 42. 1000 µF output voltage (averag...

Page 25 AN3212 Measurements Figure 44. 1000 µF output current (peak) Figure 45. 1000 µF output power Doc ID 17427 Rev 1 25/35

Page 26 Measurements AN3212 Figure 46. 1000 µF efficiency Figure 47. 1000 µF power factor 26/35 Doc ID 17427 Rev 1

Page 27 AN3212 Measurements 4.3 EMI filter The first version of the EMI filter has been implemented with the classic PI cell: C4 (22 n F) capacitor before the diode bridge plus C3 (22 n F) capacitor L1 coil (...

Page 28 Measurements AN3212 4.4 Thermal maps The following images were taken with a thermo camera under the following conditions: Ambient temperature: 27 °C Load: 7 W LED AC input voltage: 90 V, 115 V, 230 V,...

Page 29 AN3212 Electrical diagram 5 Electrical diagram Figure 56. Electrical diagram Doc ID 17427 Rev 1 29/35

Page 30 BOM list AN3212 6 BOM list Table 3. BOM 7.0 W version Reference Part VL PCB footprint note CN1 Header 2 5.08 mm CN2 Header 2 3.81 mm C1 100 n F 5.0x13.0 EPCOS B32921 1KV CERCAP DIA. 4x7 C2 680 p F 1 k...

Page 31 AN3212 BOM list Table 3. BOM 7.0 W version (continued) Reference Part VL PCB footprint note R4 220 Ω R5,R8 100 kΩ R6 680 kΩ R7,R13 2.2 kΩ R9 R10 10 kΩ R11 330 Ω R12 5.6 kΩ R14 8.2 kΩ R15 3.0 kΩ R16 0....

Page 32 7 W transformer specifications AN3212 7 7 W transformer specifications 7.1 Mechanical specifications Figure 57. Coil former mechanical drawing Figure 58. Transformer assembly 32/35 Doc ID 17427 Rev 1

Page 33 AN3212 7 W transformer specifications 7.2 Electrical specifications 1. BOBBIN: EE16 (4 +4 pin) 2. CORE: EE16 AL:1140 +/-25%n H/N*N (TDK PC40 MATERIAL or equivalent) 3. Primary inductance (P1 - P2): 1....

Page 34 Revision history AN3212 8 Revision history Table 5. Document revision history Date Revision Changes 19-Oct-2010 Initial release. 34/35 Doc ID 17427 Rev 1

Page 35 AN3212 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corre...

Manual Details

Brand	High Power
Pages	35
File Size	2.13 MB
Published	May 30, 2026

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Frequently Asked Questions

What protections are built into this LED driver module?

The module features dedicated Short-circuit protection and Open circuit protection for safe operation.

Can this device be used in life support or military applications?

No, it is not recommended for life sustaining/military uses unless explicitly approved in writing by an authorized representative.

What are the differences between the capacitor configurations?

The manual details both NO EL_CAP and EL_CAP measurements, allowing users to compare the overall performance of both types.

ST AN3212 Application note 3.5 W to 7 W high power factor offline LED driver based on VIPer devices

Summary

Figure 2. Initial configuration

Figure 3. Primary side schematic

Figure 4. IDlim vs Rlim - VIPer17

Figure 5. IDlim vs Rlim - VIPer27

Figure 6. No feedback on FB pin

Figure 7. Feedback on FB pin

Figure 8. Feedback voltage V_fb vs. VAC and Vout

Figure 9. Secondary side equivalent schematic

Table 1. Changes

Figure 10. V_drain, I_drain at Vin= 75 V

Figure 11. V_drain, I_drain at Vin= 100 V

Figure 12. V_drain, I_drain at Vin= 120 V

Figure 13. V_drain, I_drain at Vin= 162 V

Figure 14. V_drain, I_drain at Vin= 254 V

Figure 15. V_drain, I_drain at Vin= 325 V

Figure 16. V_drain, I_drain at Vin= 391 V

Figure 17. V_drain, I_drain at Vin= 50 V

Figure 18. Vin and Iin at Vin = 230 VAC

Figure 19. Vin and Iin at Vin = 115 VAC

Figure 20. V_out, I_out at Vin = 230 VAC, no El_cap

Figure 21. V_out, I_out at Vin = 115 VAC, no El_cap

Figure 22. V_out, I_out at Vin = 230 VAC, 1000 µF El_cap

Figure 23. V_out, I_out at Vin = 115 VAC, 1000 µF El_cap

Figure 24. Startup sequence at Vin = 230 VAC, no El_cap

Figure 25. Startup sequence at Vin = 115 VAC, no El_cap

Figure 26. Startup sequence at Vin = 230 VAC, 1000 µF El_cap

Figure 27. Startup sequence at Vin = 115 VAC, 1000 µF El_cap

Figure 28. Short-circuit protection

Figure 29. Short circuit application

Figure 30. Short circuit removal

Figure 31. Open circuit protection Vin = 277 VAC

Figure 32. Open circuit protection Vin = 90 VAC

Figure 33. Open circuit application

Figure 34. Open circuit removal

Figure 36. NO_El_Cap output voltage (average)

Figure 37. NO_El_Cap output current (average)

Figure 38. NO_El_Cap output current (peak)

Figure 39. NO_El_Cap output power

Figure 40. NO_El_Cap efficiency

Figure 41. NO_El_Cap power factor

Figure 42. 1000 µF output voltage (average)

Figure 43. 1000 µF output current (average)

Figure 44. 1000 µF output current (peak)

Figure 45. 1000 µF output power

Figure 46. 1000 µF efficiency

Figure 47. 1000 µF power factor

Figure 48. EMI (PI filter) 230 VAC

Figure 49. EMI (PI filter) 115 VAC

Figure 50. EMI (L + PI filter) 230 VAC

Figure 51. EMI (L + PI filter) 115 VAC

Figure 52. Thermal map at 90 VAC

Figure 53. Thermal map at 115 VAC

Figure 54. Thermal map at 230 VAC

Figure 55. Thermal map at 277 VAC

Table 2. Components max. temperature

Figure 57. Coil former mechanical drawing

Figure 58. Transformer assembly

Figure 59. Transformer electrical drawing

Table 4. Transformer winding data

Figure 1. EVLVIP27-7WLED VIPer27 LED driver module

1 Main characteristics

1.1 Initial configuration

Figure 2. Initial configuration

1.2 Requirements

2 Circuit description

2.1 Primary side

Figure 3. Primary side schematic

Figure 4. IDlim vs Rlim - VIPer17

Figure 5. IDlim vs Rlim - VIPer27

Figure 6. No feedback on FB pin

Figure 7. Feedback on FB pin

Figure 8. Feedback voltage V_fb vs. VAC and Vout

2.2 Secondary side

Figure 9. Secondary side equivalent schematic

2.3 Circuit variants

Table 1. Changes

3 Waveforms

3.1 Input