Abstract

An active centerpoint bus balancing system which actively maintains centerpoint voltage balance of the output capacitors in a power supply having a multi-level voltage output. The centerpoint voltage balance is maintained by a novel control circuit which efficiently transfers charge from one capacitor to the other capacitor so as to maintain the same voltage on each output capacitor. The centerpoint voltage balance minimizes the effect of loading conditions. It operates even with no load, and allows severe load unbalance on the two output capacitors without creating voltage unbalance.