Gate driver with short circuit protection
A vehicle includes an electric machine configured to provide propulsive force to the vehicle, and a power inverter configured to supply power from a traction battery to the electric machine using a first and second switch configured as a half-bridge, wherein the first switch is controlled by a gate driver. The gate driver is configured to operate in a soft turn-off mode when a load current exceeds a threshold for a time period defined by a mask timer, operate in a fast turn-off mode when the load current is below the threshold, and in response to a turn-off request received prior to expiration of the mask timer after the load current exceeds the threshold, enable the soft turn-off mode.
1. A vehicle power module comprising:
a first switch configured to drive a load; and
a first gate driver configured to
output a fast turn-off signal when a current of the load is less than a threshold;
responsive to a current of the load exceeding the threshold for a period defined by a mask timer, output a soft turn-off signal to the first switch, and
responsive to a turn-off request received prior to expiration of the mask timer while the current exceeds the threshold, inhibit output of the fast turn-off signal to the first switch for a duration greater than the period.
2. The vehicle power module of claim 1 further including a second switch and a second gate driver coupled with the second switch, wherein the first gate driver is further configured to, responsive to the current exceeding the threshold, delay a turn-on request from the second gate driver to the second switch by a dead time.
3. The vehicle power module of claim 2 , wherein the first and second switches are configured as a half bridge.
4. The vehicle power module of claim 3 , wherein the first and second switches are Insulated Gate Bipolar Junction Transistors (IGBTs) or Metal Oxide Semiconductor Field Effect Transistors (MOSFETs).
5. The vehicle power module of claim 4 , wherein the period is a short-circuit protection delay that includes a time to measure the current.
6. The vehicle power module of claim 5 , wherein the time is a delay time of a comparator coupled between a voltage across a resistor coupled between a sense emitter and a Kelvin emitter of the IGBT, and a short circuit reference voltage.
7. The vehicle power module of claim 2 , wherein the first and second switches are configured as a half bridge to flow the current from a traction battery to an electric machine that is configured to provide a propulsive force to a vehicle.
8. The vehicle power module of claim 2 , wherein the current is a current flowing from a traction battery to an inductor that is configured to boost a voltage of the traction battery to an operation voltage for an electric machine that is configured to provide a propulsive force to a vehicle.
9. A method of controlling an IGBT of a vehicle power module comprising:
outputting a fast turn-off signal to the IGBT when a load current is less than a threshold;
outputting a soft turn-off signal to the IGBT responsive to the load current exceeding the threshold for a period defined by a mask timer; and
inhibiting output of the fast turn-off signal to the IGBT for a duration greater than the period responsive to a turn-off request being received prior to expiration of the mask timer while the load current exceeds the threshold.
10. The method of claim 9 , wherein the IGBT is a high-side switch of a power inverter of a vehicle, and the load current is a traction battery current flowing to an electric machine that is configured to provide a propulsive force to the vehicle.
11. The method of claim 9 , wherein the IGBT is a high-side switch of a DC-DC converter of a vehicle, and the load current is a current flowing from a traction battery to an inductor that is configured to boost a voltage of the traction battery to an operation voltage for an electric machine that is configured to provide a propulsive force to the vehicle.
12. The method of claim 9 , wherein the period is a short-circuit protection delay that includes a time to measure the load current.
13. The method of claim 12 , wherein the time is a delay time of a voltage comparator coupled between a voltage of a current sensor coupled with the IGBT and a short circuit reference voltage.
14. The method of claim 13 , wherein the voltage of the current sensor is a voltage across a resistor coupled between a sense emitter and a Kelvin emitter of the IGBT.