POWER CONVERTER WITH SELF-DRIVEN SYNCHRONOUS RECTIFIER CONTROL CIRCUITRY

摘要

An AC-DC power converter is provided with two pairs of self-driven synchronous rectifier switches in addition to, or in place of, diode bridge rectifiers for boosting efficiency and reducing cost. An AC sensing circuit is coupled to AC input terminals, and a DC level shifting circuit applies a DC offset to an AC input signal received via the sensing circuit. A comparator circuit determines positive and negative half waves of the AC input signal relative to the DC offset value. Gate drive signals are provided for driving a first set of parallel rectifier switches during a positive half cycle of the AC input signal, and for driving a second and opposing pair of parallel rectifier switches during a negative half cycle of the AC input signal. In an embodiment, high side gate drive signals may be electrically isolated from the active rectifier control circuitry.