Advanced shutdown during fault-current conditions for semiconductor devices

A method of operating a drive circuit, the method comprising:

• providing current to a load of the drive circuit using one or more power devices that are disposed in a first voltage domain of the drive circuit;
• providing a control signal to the one or more power devices in the first voltage domain using a controller circuit disposed in a second voltage domain of the drive circuit, wherein the control signal traverses a first voltage isolation barrier arranged between the first and second voltage domain using a smart gate driver circuit;
• detecting a current fault condition in at least one of the power devices when sensing an over-current event using a current fault detection circuit disposed in the first voltage domain and producing a fault signal;
• sending the fault signal from the first voltage domain to the controller circuit disposed in the second voltage domain to indicate over-current and providing the fault signal to the smart gate driver circuit as a soft-shutdown signal to provoke desaturation voltage detection by the smart gate driver circuit in response to sensing the over-current condition;
• and
• deactivating the one or more power devices according to a soft shutdown in response to the soft-shutdown signal.

A drive system for an electric motor of a non-road electric vehicle, the system comprising:

• a half bridge inverter circuit including insulated gate bipolar transistors (IGBTs) to provide current drive to the electric motor;
• a smart gate driver circuit configured to provide control signals to the IGBTs including perform a soft shutdown of the IGBTs, wherein the smart gate driver circuit includes a desaturation (DESAT) input to receive a DESAT voltage indicating desaturation of at least one IGBT;
• an over-current detection circuit configured to sense an over-current condition in the half bridge inverter circuit and produce a fault signal in response to the detection;
• and
• level shifting circuitry configured to convert the fault signal to a DESAT signal to provoke a desaturation voltage detection by the smart gate driver circuit in response to the sensed over-current condition and initiate the soft shutdown of the IGBTs.