Extended range boost converter circuit

摘要

A power converter comprises a power transformer having a primary winding and a secondary winding flux coupled to the primary winding, input terminals for receiving an input voltage, and output terminals for providing an output voltage. A power switching arrangement comprising two pairs of switching devices arranged in a bridge configuration has a corresponding duty cycle which is selectable so as to cause the power converter to manifest different input output transfer characteristics corresponding to buck and boost modes of operation. An inductor having a single winding is coupled between the input terminals and the primary winding through the switching devices. Secondary winding rectification and filtering provides the power supply output. A reset circuit coupled to the output terminal of the single winding inductor and connected to the input terminals provides a current path for discharging the inductor during a predetermined time interval corresponding to that portion of the duty cycle when all of the switching devices are off to enable operation of the power supply in a buck mode of operation.