Patent ID: 8013477

Claim:
A power system comprising: a voltage regulator having a voltage input port for receiving a first voltage, and a voltage output port for outputting a second voltage; a first capacitor electrically connected between the voltage input port of the voltage regulator and a voltage reference level; a power input module comprising: a transformer having a primary winding for receiving an input voltage, a secondary winding, and an auxiliary winding; a rectification unit, electrically connected between the secondary winding and the voltage input port of the voltage regulator, for generating the first voltage; a switch, electrically connected to the primary winding in series, for controlling a current flowing through the primary winding; and a switch control unit, electrically connected to the auxiliary winding and the switch, for controlling the switch; and a switching signal generation unit, electrically connected to the voltage output port of the voltage regulator, for generating a switching signal to disable the switch control unit during a disable interval so as to decrease the first voltage from a first predetermined voltage to a second predetermined voltage.