Patent ID: 7602623

Claim:
A apparatus to regulate voltage, the apparatus comprising: a power supply that regulates a direct current (“DC”) regulated bus to maintain a regulated bus voltage under varying load conditions, the power supply comprising at least one pulse-width modulated stage, each pulse-width modulated stage comprising at least two switches connected in parallel, each switch comprising a fuse connected in series with the switch that disconnects the switch in response to an over current condition sufficient to open the fuse; and a pulse-width modulator for each stage of the power supply that regulates a bus voltage controlled by the stage by sensing the controlled bus voltage and adjusting a switching duty cycle to regulate the controlled bus voltage to a target value, wherein the pulse-width modulator for a stage provides a substantially identical switching duty cycle to each switch of the stage, the switching duty cycle comprising a signal to control a switch on and then off for a portion of a switching period.