Patent ID: 7339772

Claim:
An electronic device comprising: first electronic circuitry; and a protection circuit in electrical communication with the first electronic circuitry, said protection circuit comprising: a switch coupled to said first electronic circuitry and configured to couple said first electronic circuitry with a source of power; a first detector configured to detect power from said source of power, said first detector operatively coupled with said switch, wherein said switch closes responsive to said first detector; a second detector configured to detect noise in said power, wherein said switch opens responsive to said second detector; a positive terminal; and a negative terminal, wherein said switch is a transistor device having a gate terminal, a source terminal, and a drain terminal, said second detector comprising: a bias voltage source; and an operational amplifier having: an inverting input coupled to a positive voltage potential of said source of power and coupled with said bias voltage source; a non-inverting input coupled with a negative voltage potential of said source of power; and an output coupled to said gate terminal of said switch, wherein said bias voltage source is coupled with said first detector.