Patent ID: 9595949
Date: 2017-03-14
CPC Classifications: H02H,H02M,H03K

Claim:
1. An apparatus comprising: a clamp circuit including a first clamp circuit node, a second clamp circuit node, a power dissipation circuit, a voltage-dependent circuit element, a capacitive element, and a discharge capacitor, wherein the power dissipation circuit includes a first resistor and a clamp switch, the clamp switch having a control input, the first resistor being serially connected to the clamp switch between the first clamp circuit node and the second clamp circuit node, wherein the voltage-dependent circuit element is connected to the first clamp circuit node, the voltage-dependent circuit element having an associated voltage threshold value, wherein the capacitive element is connected to the control input, the voltage-dependent circuit element being serially connected to the capacitive element in a control path between the first clamp circuit node and the control input, wherein the discharge resistor is connected between the control input and the second clamp circuit node, wherein the capacitive element is operative, in response to a transient voltage at the first clamp circuit node exceeding the voltage threshold value, to pass energy from the first clamp circuit node to the control input, thereby causing the clamp switch to operate in a saturation mode from a first time T wherein the discharge resistor is operative to discharge the capacitive element from about the second time T a main over switch including a first power switch node and a second power switch node, the main power switch being disposed in a circuit path between the first power switch node and the second power switch node, the first clamp circuit node being electrically coupled to the first power switch node, the second clamp circuit node being electrically coupled to the second power switch node, the main power switch being operative, upon a selective activation of the main power switch, to switch between providing a high impedance and a low impedance on the circuit path between the first power switch node and the second power switch node; and a detector circuit operative to monitor a current conveyed on the circuit path through the main power switch, and to initiate opening of the main power switch depending upon a magnitude of the monitored current.