Gate driver for a full-bridge lossless switching device

Claim 2

A control circuit adapted to drive one switching device of an edge resonant converter bridge circuit comprising: a first switch means directly coupled to said switching device and comprising a series of transistors for turning on said switching device; a second switch means directly coupled to said switching device and comprising a series of transistors for turning off said switching device; said first switch means including means for disabling operation of said second switch means; said second switch means including means for disabling operation of said first switch means; and a voltage sensing means directly coupled to said switching device and comprising a unidirectional current device connected in series relationship with a small switching device for sensing the voltage across said switching device and for turning on said switching device at a time which ensures substantially lossless switching.

Claim 3

The control circuit of claim 1 wherein said voltage sensing means is adapted to turn said switching device on when the voltage across said switching device is approximately zero.

Claim 4

A control circuit adapted to drive a switching device of an edge resonant voltage converter bridge circuit wherein said control circuit comprises: a first circuit means directly coupled to said switching device and comprising a series of transistors arranged to turn on said switching device; a second circuit means directly coupled to said switching device and comprising a series of transistors arranged to turn off said switching device; and a voltage sensing means directly coupled to said switching device and comprising a unidirectional current device connected in series relationship with a small switching device for turning on said switching device when the voltage across said switching devices reaches a predetermined minimum level.

Claim 5

A control circuit adapted to drive a switching device of an edge resonant voltage converter bridge circuit wherein said control circuit comprises: a first circuit means directly coupled to said switching device and comprising a series of transistors arranged to turn on said switching device; a second circuit means directly coupled to said switching device and comprising a series of transistors arranged to turn off said switching device; and a voltage sensing means directly coupled to said switching device and comprising a unidirectional current device connected in series relationship with a small switching device for turning on said switching device when the voltage across said switching devices reaches a predetermined minimum level.

Claim 6

The control circuit of claim 3 wherein said switching device constitues a field effect transistor.

Claim 7

The control circuit of claim 3 wherein said voltage sensing means further comprises: an input connected to one side of said switching device, said unidirectional current device being connected to said input; an output connected to said first circuit means; said small switching device being connected between said output and a predetermined reference voltage; and an input to said small switching device connected to said unidirectional current device and to said predetermined reference voltage through the parallel combination of a resistor and a second unidirectional current device.

Claim 8

The voltage sensing means of claim 5 wherein said small switching device is a field effect transistor.

Claim 9

The voltage sensing means of claim 6 wherein said unidirectional current device is a diode.

Claim 10

The control circuit of claim 3 wherein said control circuit further comprises: a second switching device connected to said switching device to form one leg of a voltage converter bridge; a third circuit means directly coupled to said switching device and comprising a series of transistors arranged to turn on said second switching device; a fourth circuit means directly coupled to said second switching device and comprising a series of transistors arranged to turn off said second switchig device; a second voltage sensing means connected to said second switching device and comprising a third unidirectional switching device connected in series relationship with a second small switching device for turning on said second switching device when the voltage across said second switching device reaches a predetermined minimum level; and inputs to said voltage sensing means and said second voltage sensing means being connected to the junction between said switching device and said second switching device.