Power supply circuit and power conversion device

摘要

A power conversion device (301) includes an inverter circuit (304) converting DC power into AC power and including switching devices (130 and 150) constituting upper and lower arms, a control circuit (302) controlling the switching devices (130 and 150), a drive circuit (106) driving the switching devices (130 and 150) by a signal from the control circuit (302), and an insulated power supply circuit (190) which supplying power to the drive circuit (106). The control circuit (302) controls a power supply voltage to be outputted from the power supply circuit (190) to the drive circuit (106). The drive circuit (106) drives the switching devices (130 and 150) based on a carrier frequency (fc) and the power supply voltage. The power supply circuit (190) includes a feedback output circuit (107) through which the voltage outputted to the drive circuit (106) is outputted to a power supply control IC (101). The feedback output circuit (107) includes a dummy load circuit (201) which controls the voltage to be outputted to the power supply control IC (1101) based on a change of the carrier frequency (fc).