System and method for driving a power field-effect transistor (FET)
AssigneeTexas Instruments Incorporated
InventorsJames Allen Kohout, David John Baldwin
Life of this patent
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Abstract
A system and method is provided for driving a power field-effect transistor (FET). In one embodiment, a system comprises a control circuit that generates a control signal to provide a gate voltage of the power FET. The system further comprises a slope control circuit coupled between the control circuit and the power FET that is operative to dynamically control the rate-of-change of a gate voltage of the power FET to reduce electromagnetic interference (EMI) emissions and power loss resulting from switching the power FET.
Claims18
A system for driving a power field-effect transistor (FET) comprising:
- a control circuit that generates a control signal to provide a gate voltage of the power FET;
- a slope control circuit coupled between the control circuit and the power FET operative to dynamically control a rate-of-change of a gate voltage of the power FET to reduce electro-magnetic interference (EMI) emissions and power loss resulting from switching the power FET, wherein the slope control circuit comprises a switch interconnecting a gate terminal of the power FET and a current mirror, the current mirror supplying a minimal constant current to reduce a rate-of-change of the gate voltage of the power FET upon the switch being closed.
A system for driving a power field-effect transistor (FET) comprising:
- a control circuit that generates a control signal to provide a gate voltage of the power FET;
- and
- a slope control circuit coupled between the control circuit and the power FET operative to dynamically control a rate-of-change of a gate voltage of the power FET to reduce electro-magnetic interference (EMI) emissions and power loss resulting from switching the power FET, wherein the slope control circuit comprises a sensing circuit operative to sense a current flow through the power FET to determine that the power FET has become activated, the sensing circuit comprising a current sensing resistor and a comparator, the comparator being operative to sense the current flow through the power FET by sensing a voltage differential of a first terminal of the current sensing resistor relative to a second terminal of the current sensing resistor.
A system for driving a power field-effect transistor (FET) comprising:
- a control circuit that generates a control signal to provide a gate voltage of the power FET;
- a slope control circuit coupled between the control circuit and the power FET operative to dynamically control a rate-of-change of a gate voltage of the power FET to reduce electro-magnetic interference (EMI) emissions and power loss resulting from switching the power FET,
- wherein the power FET and the slope control circuit are contained within a single integrated circuit (IC) that comprises a sensing circuit operative to sense that the power FET has become activated and wherein the sensing circuit comprises a plurality of matched FETs, the matched FETs being substantially identical in electrical characteristics to the power FET.
Dependencies are inferred from the claim text.