SLUAAJ0 February   2024 TPS51397A , TPS54308 , TPS54320 , TPS54350 , TPS54620 , TPS54622 , TPS54821 , TPS54824 , TPS563300 , TPS566231 , TPS566235 , TPS566238 , TPS568230 , TPS56C215 , TPS62933 , TPS62933F , TPS62933O

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Comparison of Feedback Sense Methods with Second Stage Filter
  6. 3Transfer Function Derivation of PCM Converter with Second Stage Filter and Hybrid Sense
  7. 4Overall Loop Model
  8. 5Zero and Pole Analysis
  9. 6Stability Design Method
  10. 7Design Example and Experimental Validation with TPS62933F
  11. 8Summary
  12. 9References
  13.   A Appendix

8 Summary

A components selection method for second stage filter is proposed in this application note to make sure converter stability. Three types of feedback network design to support second stage filter are introduced at first and the advantages of hybrid sensing feedback is highlighted. On the basis, the loop response of peak current mode converter with second stage filter is analyzed at first. Then the expressions of zeros and poles introduced by second stage filter and hybrid sensing are derived through small signal analysis. The stability design method and low ripple power design flow are further proposed. Finally, the proposed method is verified by experiments.