1 / 37

Switching Power Supply

Switching Power Supply. Team 22 Tony Lin Hsin-Cheng Yao TA: Chad Carlson ECE 445 Fall 2004 12/01/2004. Switching Power Supply. Conversion from AC voltage to DC voltage A smart regulator Crucial component in many electronic devices such as computer and its peripherals . Benefits of SPS.

liliha
Download Presentation

Switching Power Supply

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Switching Power Supply Team 22 Tony Lin Hsin-Cheng Yao TA: Chad Carlson ECE 445 Fall 2004 12/01/2004

  2. Switching Power Supply • Conversion from AC voltage to DC voltage • A smart regulator • Crucial component in many electronic devices such as computer and its peripherals

  3. Benefits of SPS • High efficiency and less heat generation • Tighter regulation • Smaller size and weight

  4. Block Diagram

  5. Schematics

  6. Final Display

  7. AC Input • The AC input is simply the commercial AC power supply, a plug is connected to our device input for users to simply connect our product to outlets on the wall.

  8. Bridge Rectifier

  9. Unrectified and Rectified Signal

  10. Filter and Filtered Signal

  11. Flyback Converter Vout/Vin = (N2/N1) * D/(1-D)

  12. Transformer • Core Geometry: E-E • Core Model: EE 25/18 • N1:N2:N3 = 108:12:18

  13. Duty Ratio Control • Duty ratio represents the on-time of the nMOS switch

  14. Two Cases that Cause the Duty to Change • When input voltage changes • When load changes

  15. Case 1: When input voltage changes with constant load at 10 ohms

  16. Case 2: When load changes with constant input at 110V

  17. Output Filter

  18. The Load Electronic Load

  19. Optical Coupler

  20. PWM and Feedback

  21. PWM Control of the nMOS Switch • PWM regulates the on or conduction time of the switching transistor. • As the width of the pulse is increased, the switching transistor stays on longer, and more energy is applied to the switching transformer. This produces an increase in the DC output current.

  22. Design Process

  23. Design Process

  24. Design Process

  25. Performance Measurements

  26. Output Voltage Regulation

  27. Output Voltage Regulation

  28. Efficiency

  29. Power Loss • The three parts of the circuits that contribute to the most power dissipation

  30. Bridge Rectifier • The reverse diodes in the bridge rectifier consumes power • A power dissipation of 4.7W at maximum current from the spec sheet • Prectifier ~ 1.5W for our circuit

  31. Transformer • The Core Loss in Transformer • Hysteresis Loss and Eddy Current Loss • Ptransformer = P0 fa Bb

  32. nMOS Switch • Conduction Loss • Switching Loss • Pswitching loss = f Voff Ion (ton + toff) / 6 • Pswitching loss ~ 2W for our circuit

  33. Challenges and Success • Grounding Problem • Regulated Output and Close-to-Proposed Efficiency

  34. Recommendations • Find another nMOS switch with a lower power dissipation • Use of “pot-cores” for transformer • Double fuses on the input end to better protect the circuits

  35. References • Elements of Power Electronics, Krein • Phillips UC3842 Datasheet • Understanding Switch Mode Power Supplies, Sencore Tech Tips • Switching Regulators, WebEE.com

  36. Acknowledgements • Special thanks to Chad throughout the whole project and showing the “damages” done on our diodes under microscope • Professor Swenson • Professor Chapman for advices • Brett and Zach, the Power TAs

  37. Q & A Thank You!

More Related