SLVAF45 August   2021 TPS51397A , TPS566231 , TPS566235 , TPS566238 , TPS568230

 

  1.   Trademarks
  2. 1Introduction
  3. 2Why We Need Cff in High Output Voltage D-CAP2/3 Converter for Stability
  4. 3Effects of Feedforward Capacitor on the Loop
  5. 4Cff Choose Method
  6. 5Application Design Example of D-CAP2/D-CAP3 Converter with Cff
  7. 6Experimental Verification
  8. 7Conclusion
  9. 8References
  10. 9Appendix A

6 Experimental Verification

The bode plot test result with 180 uF output capacitors and no Cff is shown in Figure 6-1 for comparison. It could be seen that the phase margin is 17.228 degree. The crossover frequency is about 18.54 kHz.

GUID-20210302-CA0I-HVKK-FX5H-BMS2VV6GC52K-low.gif Figure 6-1 Experimental Result without Cff

Figure 6-2 shows the validation result with chosen Cff=120 pF using the proposed method. It can be seen that bandwidth is increased from 18.54 kHz to 47.22 kHz, while the phase margin is increased from 17.228 degree to 75.353 degree. Both dynamic performance and stability can be enhanced with the 120 pF Cff. That proves the effectiveness of the proposed method.

GUID-20210302-CA0I-6MTQ-VKJF-DGVXXT27ZC92-low.gif Figure 6-2 Experimental Verification of Proposed Method