Controlled switch-off of a power switch

1. A method comprising:

detecting, by a driver, an emergency event within a power circuit that includes: a switch for controlling current to a resistive-inductive-capacitive load and a clamp; and

performing, by the driver, a controlled emergency switch-off operation of the switch in response to the emergency event by at least limiting a voltage at the switch to a value that prevents the clamp from driving the switch into clamping operation and that prevents a rise in junction temperature of the switch, wherein performing the controlled emergency switch-off operation of the switch in response to the emergency event comprises:

initiating a fast gate discharge of the switch;

detecting a current output of the switch;

ceasing the fast gate discharge of the switch in response to determining that the current output of the switch satisfies a current threshold; and

initiating a slow gate discharge of the switch after ceasing the fast gate discharge of the switch.

2. The method of claim 1 , wherein the current threshold is based on a current trip level hysteresis of the load current for minimizing a maximum junction temperature of the switch during the controlled emergency switching operation.

3. The method of claim 1 , further comprising:

refraining from performing, by the driver, the controlled emergency switch-off operation of the switch during a non-emergency event within the power circuit.

4. The method of claim 1 , further comprising:

driving, by the driver, the switch in an on-state of the switch prior to the emergency event.

5. The method of claim 1 , wherein the emergency event is detected while the switch is being driven in the on-state.

6. The method of claim 1 , further comprising:

ceasing, by the driver, from driving or sinking a gate charge associated with the switch prior to performing the controlled emergency switch-off operation.

7. The method of claim 1 , wherein the switch comprises a semiconductor type power switch.

8. The method of claim 1 , wherein the driver comprises a shutdown unit for at least performing the controlled emergency switch-off operation of the switch in response to the emergency event.

9. A power circuit comprising:

a switch coupled to a resistive-capacitive-inductive load;

a clamp; and

a driver for controlling the switch, wherein the driver is configured to perform a controlled emergency switch-off of the switch in response to an emergency event detected within the power circuit by at least limiting a voltage at the switch to a value that prevents the clamp from driving the switch into clamping operation and that prevents a rise in junction temperature of the switch, wherein the driver is configured to perform the controlled emergency switch-off operation of the switch in response to the emergency event by at least:

initiating a fast gate discharge of the switch;

detecting a current output of the switch;

ceasing the fast gate discharge of the switch in response to determining that the current output of the switch satisfies a current threshold; and

initiating a slow gate discharge of the switch after ceasing the fast gate discharge of the switch.

10. The power circuit of claim 9 , wherein the driver further comprises:

a first stage and a second stage, wherein the driver is configured to perform the controlled emergency switch-off of the switch by at least:

enabling the first stage to perform the fast discharge of gate charge at the switch; and

enabling the second stage to perform the slow discharge of gate charge at the switch after disabling the first stage.

11. The power circuit of claim 10 , wherein:

the first stage comprises at least one of a first current mirror or a first operational amplifier, and

the second stage comprises at least one of a second current mirror or a second operational amplifier.

12. The power circuit of claim 9 , wherein the driver further comprises:

a sense unit, wherein the driver is further configured to detect the emergency event based on a current level at the sense unit.

13. A power circuit comprising:

a switch coupled to a resistive-capacitive-inductive load;

a clamp; and

a driver coupled to the switch, wherein the driver comprises:

means for detecting an emergency event within the power circuit; and

means for performing a controlled emergency switch-off operation of the switch in response to the emergency event by at least limiting a voltage at the switch to a value that prevents the clamp from driving the switch into clamping operation and that prevents a rise in junction temperature of the switch, wherein the means for performing the controlled emergency switch-off operation comprise:

means for initiating a fast gate discharge of the switch;

means for detecting a current output of the switch;

means for ceasing the fast gate discharge of the switch in response to determining that the current output of the switch satisfies a current threshold; and

means for initiating a slow gate discharge of the switch after ceasing the fast gate discharge of the switch.