GaN Active Rectifier Diode

Active or synchronous rectification is used today to further increase the efficiency of mass market power supplies by eliminating the turn-on voltage of rectifier diodes, thus reducing conduction losses. However, the active rectification is usually realized by two devices: a power MOSFET and a control circuit to imitate an ideal diode behavior. This paper presents a GaN active rectifier diode consisting of a 600 V power transistor, a control circuit with gate driver, and a supply generation, all monolithically realized in a GaN power integrated circuit (IC). This enables a true two-terminal device that can directly replace a rectifier diode. In order to evaluate the proposed conduction loss reduction by replacing a rectifier diode by an active diode, the theoretical limits at circuit level and at semiconductor level are analyzed. The GaN active rectifier diode is demonstrated in a half-wave rectification (110/230 VAC, 50/60 Hz) up to a forward current of 6 A. A single-device realization of low-loss GaN active rectifier diodes is more cost-efficient than a multi-chip or package-integrated solution.