Abstract: A power supply unit includes an input terminal, an output terminal, a main circuit, an ORing field effect transistor, a driving circuit and a switch. The main circuit is connected between the input terminal and the output terminal. The ORing field effect transistor is connected between the output terminal and the main circuit. The driving circuit is connected with a control terminal of the ORing field effect transistor. The driving circuit generates a control signal to control the ORing field effect transistor. The switch is connected between the driving circuit and the control terminal of the ORing field effect transistor. Before the power supply unit is plugged into a system bus of a power supply system, the control signal from the driving circuit is bypassed by the switch. Consequently, the ORing field effect transistor is turned off.

Abstract: A power device includes a power factor corrector, an auxiliary capacitor, a switching device, an auxiliary boost circuit, a controller and a voltage conversion device. The switching device has a first end electrically connected to the output end of the power factor corrector, and a second end electrically connected to one end of the auxiliary capacitor. An output end of the auxiliary boost circuit is electrically connected to the output end of the power factor corrector, an input end of the auxiliary boost circuit is electrically connected to a middle end of the switching device, and a ground end of the auxiliary boost circuit is electrically connected to another end of the auxiliary capacitor. The controller is electrically connected to the switching device and the auxiliary boost circuit. The input end of the voltage conversion device is electrically connected to the output end of the power factor corrector.

Abstract: A power device includes a power factor corrector, an auxiliary capacitor, a switching device, an auxiliary boost circuit, a controller and a voltage conversion device. The switching device has a first end electrically connected to the output end of the power factor corrector, and a second end electrically connected to one end of the auxiliary capacitor. An output end of the auxiliary boost circuit is electrically connected to the output end of the power factor corrector, an input end of the auxiliary boost circuit is electrically connected to a middle end of the switching device, and a ground end of the auxiliary boost circuit is electrically connected to another end of the auxiliary capacitor. The controller is electrically connected to the switching device and the auxiliary boost circuit. The input end of the voltage conversion device is electrically connected to the output end of the power factor corrector.

Abstract: A surge current suppression circuit includes a switch, a bypass resistor, a detection resistor, and a comparator. The switch is coupled to a first end of an energy storage capacitor in series, wherein a second end of the energy storage capacitor is coupled to a load and receives an input power source. The bypass resistor is coupled to the switch in parallel. The detection resistor is coupled to the switch in series to generate a detection voltage according to a capacitor current flowing through the energy storage capacitor. The comparator compares the detection voltage with a reference voltage to generate a control signal. When the detection voltage is greater than the reference voltage, the control signal controls the switch to be turned off. When the detection voltage is less than the reference voltage, the control signal controls the main switch to be turned on.

Abstract: An active bridge rectifier circuit includes a rectifier unit and a control unit. The rectifier unit includes a first upper bridge switch, a second upper bridge switch, a first lower bridge switch, and a second lower bridge switch. The control unit includes a first signal comparator and a second signal comparator. The first signal comparator compares a live wire signal provided from a live wire end with a neutral wire signal provided from a neutral wire end to generate a first comparison signal. The second signal comparator compares the live wire signal with the neutral wire signal to generate a second comparison signal. The first comparison signal controls the first upper bridge switch and the first lower bridge switch. The second comparison signal controls the second upper bridge switch and the second lower bridge switch.

Abstract: A surge current suppression circuit includes a switch, a bypass resistor, a detection resistor, and a comparator. The switch is coupled to a first end of an energy storage capacitor in series, wherein a second end of the energy storage capacitor is coupled to a load and receives an input power source. The bypass resistor is coupled to the switch in parallel. The detection resistor is coupled to the switch in series to generate a detection voltage according to a capacitor current flowing through the energy storage capacitor. The comparator compares the detection voltage with a reference voltage to generate a control signal. When the detection voltage is greater than the reference voltage, the control signal controls the switch to be turned off. When the detection voltage is less than the reference voltage, the control signal controls the main switch to be turned on.

Abstract: An active bridge rectifier circuit includes a rectifier unit and a control unit. The rectifier unit includes a first upper bridge switch, a second upper bridge switch, a first lower bridge switch, and a second lower bridge switch. The control unit includes a first signal comparator and a second signal comparator. The first signal comparator compares a live wire signal provided from a live wire end with a neutral wire signal provided from a neutral wire end to generate a first comparison signal. The second signal comparator compares the live wire signal with the neutral wire signal to generate a second comparison signal. The first comparison signal controls the first upper bridge switch and the first lower bridge switch. The second comparison signal controls the second upper bridge switch and the second lower bridge switch.