Patent ID: 7511976

Claim:
A switch circuit for selectively controlling conduction of current between first and second circuit nodes of a power converter, the switch circuit comprising: a switching device having first and second switch terminals coupled with the first and second circuit nodes, respectively, and a control terminal receiving a switching signal to selectively operate the switching device in one of a conductive state and a nonconductive state for controlling the conduction of current between first and second circuit nodes; a switch driver having an output terminal coupled with the control terminal of the switching device and at least one power terminal for receiving power, the switch driver being operative to provide the switching signal according to a received switch control signal using power from the at least one power terminal; a snubber circuit having a snubber storage device and first and second snubber terminals with one of the snubber terminals being coupled with one of the first and second circuit nodes; and a supply circuit comprising; a supply storage device, an output coupled with the switch driver power terminal to provide electrical power from the supply storage device to the switch driver for operation of the switch driver, first and second input terminals with one of the input terminals being coupled with the other one of the first and second circuit nodes and the other input terminal being coupled with the other one of the snubber terminals with the supply circuit and the snubber circuit forming a series circuit between the first and second circuit nodes in parallel with the switching device, a first converter coupled with the first and second supply circuit input terminals, the first converter comprising a capacitor storage device receiving charging current from the snubber circuit to provide a first converter output voltage at first and second output terminals of the first converter, and a second converter coupled with the output terminals of the first converter to receive the first converter output voltage and providing the electrical power at the supply circuit output for operation of the switch driver, the second converter comprising an isolation circuit to electrically isolate the supply circuit output from the output terminals of the first converter.