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US 5,635,867 AGranted
High performance drive structure for MOSFET power switches
AssigneeLucent Technologies Inc.
InventorKenneth J. Timm
Life of this patent
Estimating the term…
Abstract
A high performance isolated gate drive circuit for driving MOSFET is disclosed which uses a MOSFET pull-down device, provides unusually low gate discharge impedance, exceptionally fast turn-off of the controlled switch and reduced power dissipation in the overall gate drive circuit. It also provides superior off-time noise immunity.
Claims3
A gate drive circuit for a power MOSFET having a drain, a source and a gate electrode, comprising:
- a drive transformer having a secondary winding connected to apply a source-gate voltage to the power MOSFET and charge a capacitance shunting the source-gate electrodes of the power MOSFET;
- a drive MOSFET having a drain, a source and a gate electrode and the drain electrode directly connected to a first terminal of the secondary winding and its source electrode coupled to a second terminal of the secondary winding and being operative when conducting to clamp a gate voltage of the power MOSFET and discharge the capacitance shunting the source-gate electrodes of the power MOSFET;
- drive circuitry energized through the secondary winding connected for controlling conductivity of the drive MOSFET and including a diode connecting a source electrode of the drive MOSFET to the second terminal of the secondary winding, and a capacitance shunting the source-gate electrodes of the drive MOSFET;
- and wherein the capacitance shunting the source-gate electrodes of the power MOSFET is a discreate capacitor.
1 more element
A gate drive circuit for a power MOSFET having a drain, a source and a gate electrode, comprising:
- a drive transformer having a secondary winding connected to apply a source-gate voltage to the power MOSFET and charge a capacitance shunting the source-gate electrodes of the power MOSFET;
- a drive MOSFET having a drain, a source and a gate electrode and the drain electrode directly connected to a first terminal of the secondary winding and its source electrode coupled to a second terminal of the secondary winding and being operative when conducting to clamp a gate voltage of the power MOSFET and discharge the capacitance shunting the source-gate electrode of the power MOSFET;
- drive circuity energized through the secondary winding connected for controlling conductivity of the drive MOSFET and including a diode connecting a source electrode of the drive MOSFET to the second terminal of the secondary winding, and a capacitance shunting the source-gate electrodes of the drive MOSFET;
- and wherein the capacitance shunting the source-gate electrodes of the drive MOSFET is a discrete capacitor.
1 more element
A gate drive circuit for a power MOSFET having a drain, a source and a gate electrode, comprising:
- a drive transformer having a secondary winding connected to apply a source-gate voltage to the power MOSFET and charge a capacitance shunting the source-gate electrodes of the power MOSFET;
- a drive MOSFET having a drain, a source and a gate electrode and the drain electrode directly connected to a first terminal of a secondary winding and its source electrode coupled to a second terminal of the secondary winding and being operative when conducting to clamp a gate voltage of the power MOSFET and discharge the capacitance shunting the source-gate electrodes of the power MOSFET;
- drive circuitry energized through the secondary winding connected for controlling conductivity of the drive MOSFET and including a diode connecting a source electrode of the drive MOSFET to the second terminal of the secondary winding, and a capacitance shunting the source-gate electrodes of the drive MOSFET;
- and further including circuitry having a parallel connected diode and resistor connecting the gate electrode of the drive MOSFET to the secondary winding.
1 more element
Dependencies are inferred from the claim text.