Patent ID: 8432068

Claim:
An apparatus comprising: a normally-open manually operable switch; a first MOSFET having a first gate coupled to the switch, and a first source coupled to a high voltage potential terminal of a power source to receive electric power therefrom; a second MOSFET having a second source coupled to a low voltage potential terminal of the power source; a second drain coupled to the switch and to the first gate of the first MOSFET, and a second gate to receive electric power from the power source through at least the first source and a first drain of the first MOSFET; a third transistor having a third source coupled to the low potential terminal of the power source, a third drain coupled to the switch, and a third gate to receive a bias voltage through at least the first source and drain of the first MOSFET; and wherein closing the switch couples the first gate to the low potential voltage terminal of the power source through the third transistor while the third transistor is in a conductive state, placing the first MOSFET into a conductive state, providing a high voltage potential through the first MOSFET to the second gate, placing the second MOSFET into a conductive state, providing a low voltage potential to the first gate to latch the first and the second MOSFETs in a conductive state, and placing the first MOSFET into the conductive state also provides the bias voltage through the first MOSFET to the third gate, placing the third transistor into a non-conductive state, decoupling the switch from the low potential voltage terminal of the power source while the first MOSFET is in the conductive state.