Patent ID: 11909384
Assignee: GAN SYSTEMS INC.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 5:
6. A power semiconductor switching device comprising:
a high-side switch and a low-side switch connected in series in a half-bridge configuration, between a high voltage DC bus and a low voltage DC bus, the high side switch being connected to the low side switch at a switching node, wherein:
the high-side switch is a normally-off switch wherein a first normally-on GaN transistor switch (Q1) is connected in series with a normally-off Si MOSFET switch (M1), the source of Q1 being connected to the drain of M1;
the low side switch is a normally-on switch, comprising a second normally-on GaN transistor switch (Q2);
wherein gates of the D-mode normally-on GaN transistor switches Q1 or Q2 are directly driven, and the gate of the E-mode normally-off Si MOSFET M1 is directly driven by a control circuit, wherein M1 acts as a protection FET to hold the high-side switch in an off-state during start-up and during a fault condition; and
the control circuit is configured to determine an operational mode of M1 responsive to an undervoltage lock-out (UVLO) signal and a voltage sense signal indicative of an overcurrent event, the control circuit operating so that: M1 is OFF during start-up until UVLO is off; M1 is ON for normal operation; M1 is turned-off during a fault condition if UVLO is turned-on; and if overcurrent protection (OCP) is triggered, M1 is ON and Q1 and Q2 are turned-off.