SLVAG06 March   2025 TPS40210 , TPS40210-Q1 , TPS40211 , TPS40211-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Primary Side Regulation (PSR)
  6. 3Secondary Side Regulation Implementation
    1. 3.1 Common Implementation Feedback for Secondary Side Regulation
    2. 3.2 Implementing Feedback for Secondary Side Regulation
  7. 4Simulation Results
  8. 5Practical Bode Plot Comparison
  9. 6Summary
  10. 7References

6 Summary

Flyback feedback implementation is not complicated. However, there are best practices. Consider setting feedback filter to achieve stable bias IC and good transient response on the primary side regulation. On the secondary side regulation, there are two methods to implement feedback. It is not necessary to use the primary side IC internal error amplifier because of the error amplifier and compensator on the secondary side. The other method is to use the internal error amplifier of the primary control IC. When using this method, make sure that the internal error amplifier is the operation amplifier instead of transconductance amplifier. Consider the optocoupler output connection and set the suitable gain of internal error amplifier. Both methods can achieve stable loop. A simulation and practical experiment performed on the PMP40274 board verify these two methods.