Patent ID: 7741591

Claim:
An optically powered drive circuit for controlling a first semiconductor switch, comprising: a photovoltaic cell configured to receive a first light signal from a first fiber optic cable and to generate a first voltage in response to the first light signal; a second semiconductor switch configured to receive a second light signal from a second fiber optic cable and to output a second voltage; and an electrical circuit electrically coupled to both the photovoltaic cell and the second semiconductor switch, the electrical circuit being powered by the first voltage, the electrical circuit being configured to output a third voltage for controlling operation of the first semiconductor switch in response to the second voltage such that the first semiconductor switch passes electrical energy from an energy source that is independent from the optically powered drive circuit; wherein the electrical circuit comprises a third semiconductor switch configured to transition the first semiconductor switch to a first operational state in response to the second voltage being received by the electrical circuit; wherein the electrical circuit further comprises a fourth semiconductor switch configured to transition the first semiconductor switch to a second operational state in response to the second voltage not being received by the electrical circuit.