#Hybrid DCDC converter (PS3B) vs Switch-capacitor converter

Disadvantage of SC:

  • ultra-high density capacitors
  • operate over a small number of conversion ratios
  • need small inductors tend to have high DC resistance

Advantages of hybrid DCDC

  • regulate to arbitrary output voltages
  • large conversion ratio
  • input current is continuous

Topology


S1,S2S_1,S_2都断开的时候,稳定态下,VCF=VINV_{C_F}=V_{IN}

S1S_1闭合,S2S_2断开,瞬态下,VX1V_{X_1}变为VOUTV_{OUT},电容想要保持VCF=VINV_{C_F}=V_{IN}VX2=VOUTVCF=VOUTVINV_{X_2}=V_{OUT}-V_{C_F}=V_{OUT}-V_{IN}。所以电流分别从L1,L2L_1,L_2流到Output。

S2S_2闭合,S1S_1断开,瞬态下,VX2V_{X_2}变为VOUTV_{OUT},电容想要保持VCF=VINV_{C_F}=V_{IN}VX1=VOUT+VCF=VOUT+VINV_{X_1}=V_{OUT}+V_{C_F}=V_{OUT}+V_{IN}

根据电感的volt-second平衡,CFC_F is balanced at VINV_{IN}.