Switching power supply apparatus

摘要

A switching power supply apparatus of the present disclosure is a device connection state detection circuit that detects a connection state in a load device connection terminal in a power supply system having the load device connection terminal. The device connection state detection circuit includes a transformer, a switching element, a pulse generator, and a waveform detection circuit. The waveform detection circuit detects a voltage or a current generated in a primary winding wire or a secondary winding wire of the transformer in accordance with operation of a pulse signal, compares the detected voltage or current with a preset reference value, and outputs an output signal in accordance with a comparison result, to an OFF terminal.

主权项

1. A switching power supply apparatus comprising:
a second switching element to which an input voltage is supplied; an output terminal connected to a load device; an input/output conversion circuit that converts the input voltage switched by the second switching element into an output voltage, and outputs the converted output voltage to the output terminal; a switching control circuit that controls switching operation of the second switching element, and has an off mode for stopping the switching operation in accordance with a signal input to an OFF terminal; a first rectifier circuit connected between the input/output conversion circuit and the output terminal; a transformer having a secondary winding wire whose first end is connected to a first terminal of the output terminal through a second rectifier circuit; a first switching element connected to a primary winding wire of the transformer; a pulse generator that supplies a pulse signal to a gate terminal of the first switching element; and a waveform detection circuit that detects a voltage or a current generated in the primary winding wire or the secondary winding wire of the transformer in accordance with operation of the pulse signal, compares the detected voltage or current with a preset reference value, and outputs an output signal in accordance with a comparison result to the OFF terminal.