Patent ID: 8106643

Claim:
A power supply apparatus, comprising: a first power supplier, configured for receiving a direct current (DC) input voltage and generating a DC output voltage accordingly, the first power supplier comprising: a main power generating unit, configured for receiving and converting the DC input voltage so as to generate a main power accordingly; an isolation diode, coupled to the main power generating unit, the isolation diode having an anode receiving the main power and a cathode outputting the DC output voltage; a first resistor having a first terminal coupled to the anode of the isolation diode; a voltage feedback controller, coupled to a second terminal of the first resistor and the main power generating unit, configured for providing a control signal to control the main power generating unit according to a voltage of the second terminal of the first resistor, so as to regulate the main power; and a voltage difference detecting unit, coupled to the cathode of the isolation diode and the second terminal of the first resistor, configured for comparing a voltage of the cathode of the isolation diode with a voltage of the second terminal of the first resistor, so as to control the voltage of the second terminal of the first resistor always equal to the voltage of the cathode of the isolation diode, and thus making the first power supplier stably output the DC output voltage.