Abstract: The present invention presents an uninterruptible power supply device including an input circuit coupled between a voltage input terminal and a rectifier circuit, in which the input circuit includes a boost choke being charged with an AC current received from the voltage input terminal for providing a boosted AC voltage to the rectifier circuit. The rectifier circuit is configured to convert the boosted AC voltage into an intermediate DC voltage. The intermediate DC voltage is converted through an inverter into a poly-phase output AC voltage for use by a load.

Abstract: A charging circuit includes a main power circuit, a DC-to-DC converting circuit, a detection circuit and a controller. The main power circuit is electrically connected to a power source for converting an input voltage from the power source into a first voltage. The DC-to-DC converting circuit is electrically connected to the main power circuit for converting the first voltage into a second voltage to charge the energy storage element. The detection circuit is electrically connected to the main power circuit and the DC-to-DC converting circuit for detecting a terminal voltage of the energy storage element and the first voltage from the main power circuit, thereby generating a feedback signal. The controller is electrically connected to the detection circuit and the main power circuit for controlling operations of the first switching element in response to the feedback signal, so that the first voltage is adjustable according to the second voltage.

Abstract: The present invention presents an uninterruptible power supply device including an input circuit coupled between a voltage input terminal and a rectifier circuit, in which the input circuit includes a boost choke being charged with an AC current received from the voltage input terminal for providing a boosted AC voltage to the rectifier circuit. The rectifier circuit is configured to convert the boosted AC voltage into an intermediate DC voltage. The intermediate DC voltage is converted through an inverter into a poly-phase output AC voltage for use by a load.

Abstract: A charging circuit applicable to an uninterruptible power supply for receiving an input DC voltage and converting the input DC voltage into a desired DC output voltage is provided. The charging circuit includes a voltage divider for receiving the input DC voltage and dividing the input DC voltage into a plurality of fractional voltages, a switch device connected to the voltage divider and having a plurality of switch elements, a transformer having a primary side and a secondary side in which one end of the primary side is connected to the switch device and the other end of the primary side is connected to the voltage divider, a control device for detecting the output DC voltage and generating a plurality of control signals accordingly to enable the switch elements of the switch device to turn on and off alternately, and a smoothing circuit connected to the secondary side of the transformer for rectifying and filtering the output voltage of the transformer to provide the output DC voltage.