US 7,612,602 B2 · Resonant gate drive circuits

Abstract

A resonate gate drive circuit for driving at least one power switching devices recovers energy loss for charging and discharging the input capacitance of the power switching devices. The gate drive circuit charging and discharging the gate capacitor with a high level current, so the switching loss of the power switching devices can also be reduced. The gate drive circuit can clamp and keep the voltage across the gate capacitor to a certain level while the power switching devices turn on, and it can also clamp and keep the voltage across the gate capacitor to almost zero while the power switching devices turn off. The gate drive circuit comprises four small semiconductor bidirectional conducting switching devices connected in full-bridge configuration. An inductor is connected to the two junctions of the full-bridge configuration to help switching the current direction. A capacitor in series with the inductor is necessary for some applications. A bootstrap circuit, which is widely used in conventional gate drive circuitry, is also necessary for this resonant gate drive circuit when it is adopted for high-side and low-side applications.

Claims46

Dependent claims

A method of controlling operation of first and second power switching devices having gate capacitors, comprising:

charging the gate capacitors of the first and second power switching devices at a high current level;
connecting the gate capacitors of the first and second power switching devices to a voltage source, via a first low impedance path, while the first and second power switching devices are on;
discharging the gate capacitors of the first and second power switching devices at a high current level;
and maintaining the voltage across the gate capacitors of the first and second power switching devices at a low voltage via a second low impedance path while the first and second power switching devices are off;
so as to reduce energy loss for charging and discharging the gate capacitors of the first and second power switching devices and to reduce switching loss of the first and second power switching devices;
wherein the gate capacitors are directly between a gate and a source, an emitter, or a cathode of the first and second power switching devices and are part of the power switching devices;
wherein the charging, connecting, and discharging are performed on the gate capacitors of the first and second power switching devices at different times;
wherein an inductor is directly connected between the gate capacitors of the first and second power switching devices;
and
wherein the first and second power switching devices are selected from MOSFET, IGBT and MCT.

7 more elements

A resonant gate drive circuit for use with a power source having a positive terminal and a negative terminal, comprising:

an inductor having a first terminal and a second terminal;
a first capacitor having a first terminal and a second terminal;
a second capacitor having a first terminal and a second terminal;
a unidirectional conducting device having an anode terminal and a cathode terminal;
a first terminal of a first switch being connected to said cathode terminal of said unidirectional conducting device and to said first terminal of said second capacitor;
a first terminal of a second switch being connected to said positive terminal of said power source and to said anode terminal of said unidirectional conducting device;
a first terminal of a third switch being connected to a second terminal of said first switch and to said first terminal of said inductor;
a first terminal of a fourth switch being connected to a second terminal of said second switch and to said second terminal of said first capacitor;
a second terminal of said third switch being connected to said second terminal of said second capacitor;
a second terminal of said fourth switch being connected to said negative terminal of said power source;
the said second terminal of said inductor being connected to said first terminal of said first capacitor;
a gate capacitor of a fifth switch being connected in parallel with said third switch;
and
a gate capacitor of a sixth switch being connected in parallel with said fourth switch.

11 more elements

Dependencies are inferred from the claim text.

Resonant gate drive circuits

Life of this patent

Resonant gate drive circuits

Life of this patent

Abstract

Claims46