SYNCHRONOUS RECTIFIER DISABLING ARRANGEMENT

摘要

A power supply (200) receives an alternating current input (102) that is rectified by a rectifier (230). The rectified output voltage (132) is coupled to a load (500) and a microprocessor (400) during both a run mode operation and a standby mode operation. The rectifier (230) provides synchronous rectification by an included MOSFET (234), during the run mode operation and non-synchronous rectification during the standby mode operation by an included Schottky diode (232). The Schottky diode (232) in rectifier (230) is in parallel with the MOSFET (234) and provides rectification during the standby mode operation. A source (400) of an on/off control signal (203) from the microprocessor (400) is applied to the load for changing the operation mode and applied, in parallel, to the rectifier (230) for disabling the synchronous rectification in the rectifier (230), during the standby mode operation. The efficiency of the power supply (200) is improved in the standby mode operation by elimination of the power consumed to energize a synchronous rectifier controller (236). The efficiency of the power supply (200) is also improved in the standby mode operation by using the on/off control signal (203) from the microprocessor (400) to disable the synchronous operation.