Patent ID: 6479970
Filing Date: 2002-11-12
Classification: H02J,H02M

Abstract:
An un-interruptible power supply coupled to receive a dc input voltage at a dc input voltage node referenced to a first reference potential node, and to provide an isolated output dc voltage referenced to a second reference potential node to a load comprising:a mode control circuit coupled to monitor the dc input voltage and to provide a mode selection signal having a first state in response to the dc input voltage exceeding a first voltage level and a second state in response to the dc input voltage passing below a second voltage level, a high frequency transformer having at least a primary winding, an output winding and a charger winding, a battery having a battery voltage at a battery first terminal measured with respect to a battery second terminal, the battery second terminal being coupled to a third reference potential node, an input inverter referenced to the first reference potential node and coupled to transfer power from the dc input voltage, to provide pulse width modulated power to the primary winding of the high frequency transformer, an output rectifier and filter driven by the transformer output winding to provide the output dc voltage referenced to the second reference potential node, an adaptive converter referenced to the third reference potential node and coupled to the transformer charger winding for charging the battery in response to the mode selection signal first state to transfer power from the battery to the transformer charger winding to provide the output dc voltage source in response to the mode selection signal second state.