Circuit and method for managing common mode noise in isolated resonant DC-DC power converters

摘要

A resonant DC/DC power converter is provided with isolated primary and secondary circuits. The primary circuit includes at least four switches as first and second pairs in a bridge configuration, an isolation transformer having at least one primary and at least one secondary winding, and a resonant tank including a resonant capacitor and a split resonant inductor having two separate windings. In one embodiment, the split resonant inductor windings are substantially identical. Synchronous switching of diagonally opposed switch pairs in the bridge configuration thereby produces a center point voltage of the primary transformer winding is substantially free of stepwise voltage changes.

主权项

1. A resonant DC/DC power converter comprising:
a primary circuit further comprising
a first inverter branch comprising a first pair of switches coupled in series across an input power source and connected together at a first output node,a second inverter branch comprising a second pair of switches coupled in series across the input power source and connected together at a second output node, anda resonant tank branch laterally coupled between the first and second output nodes, the resonant tank branch comprising first and second resonant capacitors, a primary winding of an isolation transformer and a split resonant inductor having two separate windings,wherein the resonant tank branch further defines first and second impedance circuits on opposing sides of the primary winding and having equivalent impedance values; and a secondary circuit coupled to a secondary winding of the isolation transformer, wherein in response to symmetrical switching of the first and second pairs of switches, a center point voltage of the primary transformer winding is substantially free of stepwise voltage changes.