POWER SUPPLY APPARATUS

摘要

Provided is a technique of detecting not only a main DC voltage but also an auxiliary DC voltage to protect a main rectifier circuit and an auxiliary rectifier circuit. A main power supply circuit (119) drives a load (121). A main rectifier circuit (11) receives an AC voltage through a first switch (102) to supply the main power supply circuit (119) with a main DC voltage (Vdc1). The first switch (102) is turned off when an overcurrent flows through the main power supply circuit (119) or the load (121) is an overload for the main power supply circuit (119). A control circuit (123) is supplied with operating power from an auxiliary power supply circuit (117). An auxiliary rectifier circuit (12) receives the AC voltage while bypassing the first switch (102) to supply the auxiliary power supply circuit (117) with an auxiliary DC voltage (Vdc2). A DC voltage detection circuit (13) detects the main DC voltage (Vdc1) and the auxiliary DC voltage (Vdc2).