Resonant gate drive circuit with centre-tapped transformer
AssigneeQueen's University at Kingston
InventorsYan-Fei Liu, Kai Xu
Life of this patent
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Abstract
This invention relates to a resonant gate drive circuit for a power switching device, such as a MOSFET, that uses a center-tapped transformer to increase the driving gate voltage approximately twice as high as the supply voltage. The gate capacitance of the power switching device is charged and discharged by a constant current source, which increases the switching transition speed of the power switch. The circuit is suitable for driving a pair of low side switches with 50% duty cycle or less, such as in a variable frequency resonant converter, push-pull converter, or the like.
Claims22
A resonant gate drive circuit for controlling operation of at least one power switching device having a gate capacitance, comprising:
- a first input terminal for receiving a supply voltage;
- a first current source having a first terminal and a second terminal;
- a second current source having a first terminal and a second terminal;
- wherein the second terminal of the first current source and the first terminal of the second current source are connected together at a node, the at least one power switching device being connected to the first terminal of the first current source or the second terminal of the second current source;
- and
- a plurality of switches that direct the flow of current from the first current source and the second current source, to charge and discharge the gate capacitance of the at least one power switching device, and that connect the gate capacitance of the at least one power switching device to a voltage higher than the supply voltage or to a low voltage, at a selected instant in time;
- wherein operation of the at least one power switching device is controlled.
A method of controlling operation of at least one power switching device having a gate capacitance, comprising:
- (i) charging the gate capacitance of a power switching device using at least a portion of a magnetizing inductance current, so that the power switching device is switched on;
- (ii) using a current source to generate a voltage that is higher than a supply voltage, and then clamping the gate capacitance of the power switching device to the high voltage while the power switching device is on;
- (iii) discharging the gate capacitance of the power switching device using at least a portion of a magnetizing inductance current so that the power switching device is switched off, and then clamping the gate capacitance of the power switching device to a low voltage while the power switching device is off;
- and
- (iv) repeating steps (i) to (iii) as required to control operation of the at least one power switching device.
Dependencies are inferred from the claim text.