Abstract: A power supply avoiding an auxiliary boost circuit over voltage includes a direct current to direct current converting circuit, the auxiliary boost circuit and a power factor correction circuit. The auxiliary boost circuit includes a voltage detection unit, a control unit, a management unit and a boost unit. When the voltage detection unit detects that an output voltage of the power factor correction circuit is less than a predetermined voltage, the control unit enters a hold up time mode. Before the hold up time mode is finished, the control unit sends a first synchronization signal to the management unit, so that the management unit sends a second synchronization signal to the control unit, so that the control unit turns off the boost unit before or at the same time the management unit turns off the direct current to direct current converting circuit.

Abstract: A power supply apparatus includes a rectification circuit, a power factor correction circuit, an auxiliary boost circuit and a direct current to direct current conversion circuit. The auxiliary boost circuit includes an input contact, an output contact, a voltage detection unit, a control unit, a boost unit and a boost bypass unit. When a voltage value of a power factor correction power is not greater than a predetermined voltage value, the control unit is configured to turn off the boost bypass unit and turn on the boost unit, so that the boost unit boosts the power factor correction power and then the power factor correction power is sent to the direct current to direct current conversion circuit through the boost unit and the output contact.

Abstract: A power supply apparatus includes a rectification circuit, a power factor correction circuit, an auxiliary boost circuit and a direct current to direct current conversion circuit. The auxiliary boost circuit includes an input contact, an output contact, a voltage detection unit, a control unit, a boost unit and a boost bypass unit. When a voltage value of a power factor correction power is not greater than a predetermined voltage value, the control unit is configured to turn off the boost bypass unit and turn on the boost unit, so that the boost unit boosts the power factor correction power and then the power factor correction power is sent to the direct current to direct current conversion circuit through the boost unit and the output contact.