SLVAFQ5 December   2023 TPS51383 , TPS51385 , TPS51386

PRODUCTION DATA  

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Zcap Calculation of Hybrid Capacitors
  6. 3Experimental Verification
  7. 4Loop Stability Analysis With Hybrid Output Capacitor Network
  8. 5Application Design Example of D-CAP3 Converter With a Hybrid Output Capacitors Network
  9. 6Summary
  10. 7References

1 Introduction

In general, MLCCs have low capacitance and small ESR, and electrolytic capacitors have high capacitance but large ESR. Many designers use MLCCs and electrolytic capacitors in parallel to obtain high capacitance for better ripple and transient performance. However, the electrolytic capacitors have a large ESR, and in DC/DC converter small-signal model, the hybrid output capacitors introduce additional zeros and poles in the loop. And when the ESR of electrolytic capacitors is too large, the zeros and poles are pushed into the bandwidth and have a direct effect on the stability of the loop. This application note calculates the zero and pole of hybrid output capacitor and analyzes the loop stability.