Patent ID: 8223469

Claim:
A circuit interrupting device comprising: a. a first current path, traversing a mechanical contactor; b. a second current path, parallel to said first current path, traversing a switch having active feedback control, said switch including: a power transistor device having a collector, an emitter and a gate; and a zener diode connected between said collector and said gate of said transistor device; wherein a voltage drop between the collector and the emitter of said transistor device equal to or greater than the threshold voltage of said zener diode will cause said zener diode to be turned on and a voltage to be applied to said gate sufficient to turn said transistor device on and to hold said voltage drop at or near said threshold voltage until current flowing through said transistor device is reduced to zero; and c. fault detection circuitry, for detecting a fault condition; wherein a fault current is commutated from said first current path to said second current path upon detection of said fault current by said fault detection circuitry.