Gan Systems Inc.

Gan Svstems Inc.

Di Chen

Larry Spaziani

Juncheng Lu

Peter Anthony Di Maso

Xuechao Liu

Yajie Qiu

A protected direct-drive depletion-mode (D-mode) GaN semiconductor half-bridge power module is disclosed. Applications include high power inverter applications, such as 100 kW to 200 kW electric vehicle traction inverters, and other motor drives. The high-side switch is a normally-on D-mode GaN semiconductor power switch Qin series with a normally-off LV Si MOSFET power switch Mand the low-side switch is a normally on D-mode GaN semiconductor power switch Q. The gates of both Qand Qare directly driven. Min series with Qprovides a high-side switch which is a normally-off device for start-up and fail-safe protection. Mmay also be used for current sensing and overcurrent protection. For example, a control circuit determines an operational mode of Mresponsive to a UVLO signal and a voltage sense signal indicative of an overcurrent event. Examples of single phase and three-phase half-bridge modules and driver circuits are described.

Direct-drive D-mode GaN half-bridge power module

Low inductance power modules for ultra-fast wide-bandgap semiconductor power switching devices are disclosed. Conductive tracks define power buses for a switching topology, e.g. comprising GaN E-HEMTs, with power terminals extending from the power buses through the housing to provide a heatsink-to-busbar distance which meets creepage and clearance requirements. Low-profile, low-inductance terminals for gate and source-sense connections extend from contact areas located adjacent each power switching device to provide for a low inductance gate drive loop, for high di/dt switching. The gate driver board is mounted on the low-profile terminals, inside or outside of the housing, with decoupling capacitors provided on the driver board. For paralleled switches, additional terminals, which are referred to as dynamic performance pins, are provided to the power buses. These pins are configured to provide a low inductance path for high-frequency current and balance inductances of the power commutation loops for each switch.

Power modules for ultra-fast wide-bandgap power switching devices

An AC/DC Switching Mode Power Supply (SMPS) comprises a PFC stage, an isolated LLC DC/DC converter stage, and a control circuit that provides feedback/control signals to PFC and LLC controllers, to enable a plurality of operating modes, dependent on a sensed peak AC input voltage and required output voltage Vo. The PFC provides a first DC bus voltage Vdc (e.g. 200V) for low line AC input and a second DC bus voltage (e.g. 400V) for high line or universal AC input. A multi-mode LLC converter is operable in a half-bridge mode or a full-bridge mode. For low line AC input, output voltage Vo, and PFC output Vdc, the LLC operates in full-bridge mode; for high line input, output voltage Vo and PFC output 2&#xd7;Vdc, the LLC operates in half-bridge mode; for universal AC input, output voltage 2&#xd7;Vo, and PFC output 2&#xd7;Vdc, the LLC operates in full-bridge mode.

Architecture for AC/DC SMPS with PFC and multimode LLC DC/DC converter

A GaN power switching device comprises a GaN transistor switch SW_MAIN has an integrated drain voltage sense circuit, which comprises GaN sense transistor SW_SEN and GaN sense resistor R, which at turn-on form a resistive divider for sensing the drain voltage of SW_MAIN to provide a drain voltage sense output VDSEN. Fault detection logic circuitry of a driver circuit generates a fault signal FLT when VDSEN reaches or exceeds a reference voltage Vref, which triggers fast turn-off of the gate of SW_MAIN, e.g. within less than 100 ns of an overcurrent or short circuit condition. During turn-off, Rresets VDSEN to zero. For two stage turn-off, the driver circuit further comprises fast soft turn-off circuitry which is triggered first by the fault signal to pull-down the gate voltage to the threshold voltage, followed by a delay before full turn-off of the gate of SW_MAIN by the gate driver.

GaN transistor with integrated drain voltage sense for fast overcurrent and short circuit protection

A 3-level T-type neutral point clamped (NPC) inverter/rectifier is disclosed in which neutral point clamping is dynamically enabled/disabled responsive to load, e.g. enabled at low load for operation in a first mode as a 3-level inverter/rectifier and disabled at high/peak load for operation in a second mode as a 2-level inverter/rectifier. When the neutral clamping leg is enabled only under low load and low current, middle switches Sand Scan be smaller, lower cost devices with a lower current rating. Si, SiC, GaN and hybrid implementations provide options to optimize efficiency for specific load ratios and applications. For reduced switching losses and enhanced performance of inverters based on Si-IGBT power switches, a hybrid implementation of the dual-mode T-type NPC inverter is proposed, wherein switches Sand Scomprise Si-IGBTs and switches Sand Sof the neutral clamping leg comprise GaN HEMTs. Applications include electric vehicle traction inverters.

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Ottawa, Canada

Di Chen