Patent ID: 8354828

Claim:
A power supply comprising: a rectifier, for converting an alternating current (AC) voltage into a direct current (DC) voltage; a delay unit, for delaying phase of a standard clock signal to generate a plurality of synchronization clock signals; a major DC-DC converter, coupled to the rectifier and the delay unit, for adjusting level and phase of the DC voltage according to one of the plurality of synchronization clock signals to generate a major output voltage; and a plurality of parallel DC-DC converters, each coupled to the major DC-DC converter and the delay unit, for adjusting level and phase of the major output voltage according to one of the plurality of synchronization clock signals to generate a minor output voltage; wherein each of the plurality of parallel DC-DC converters comprises: an input end, for receiving the major output voltage; an output end, for outputting the minor output voltage; a feedback module, coupled to the output end, for generating a feedback signal according to the minor output voltage; a switch module comprising: a front end, for receiving a pulse width modulation (PWM) signal; a back end; an up-bridge switch transistor, coupled to the input end, the front end and the back end, for determining whether or not the input end is electrically connected to the back end according to the PWM signal; and a down-bridge switch transistor, coupled to the front end, the back end and a ground end, for determining whether or not the back end is electrically connected to the ground end according to an inverted signal of the PWM signal; an output module comprising: an output inductor, comprising one end coupled to the back end of the switch module and another end coupled to the output end; and an output capacitor, comprising one end coupled between the output inductor and the output end and another end coupled to the ground end; an oscillator, for generating a sawtooth wave signal; a first comparator, coupled to the feedback module, for comparing a first reference signal and the feedback signal to generate a comparison result; a second comparator, coupled to the first comparator, the oscillator and the front end of the switch module, for comparing the comparison result and the sawtooth wave signal to generate the PWM signal sent to the switch module; and a synchronizer, coupled to the second comparator, the front end of the switch module and the delay unit, for adjusting a phase of the PWM signal according to one of the plurality of synchronization clock signals.