Gate charge recovery circuit for gate-driven semiconductor devices

• US 5,298,797 A
• Filed: 03/12/1993
• Issued: 03/29/1994
• Est. Priority Date: 03/12/1993
• Status: Expired due to Term

• Current Assignee: Asahi Kasei Toko Power Device Corp. (Asahi Kasei Corporation)
• Original Assignee: TOKO America Incorporated (Murata Manufacturing Co Limited)
• Inventors: Redl, Richard
• Primary Examiner(s): RUBIN, MARGARET R
• Application Number:
  US08/031,223
• Time in Patent Office: 382 Days
• Field of Search: 307/520, 307/542-543, 307/572-573, 307/246, 328/167
• US Class Current: 327/387
• CPC Class Codes: H03K 17/162 without feedback from the output circuit to the control circuit
• CPC Class Codes: H03K 17/168 in composite switches
• CPC Class Codes: H03K 19/0019 by energy recovery or adiabatic operation
• CPC Class Codes: H03K 2217/0036 Means reducing energy consumption
• CPC Class Codes: H03K 2217/0081 Power supply means, e.g. to the switch driver

Abstract

A gate charge recovery circuit prevents generation of the voltage spike that would otherwise appear across the sense resistor that is employed to detect the current flowing through the switched terminal of a gate-driven semiconductor device when the device is turned on. The gate charge recovery circuit comprises the combination of a capacitor connected between the reference terminal of the semiconductor device and the positive terminal of a driver and a filter resistor connected between the positive terminal of the driver and the positive terminal of a voltage source.

Claims

1. In a circuit wherein a gate-driven semiconductor device is configured with a current sense device connected between a gate voltage reference terminal of said semiconductor device and a first terminal of a voltage source supplying a gate-driving voltage to said semiconductor device, a gate-driving device having an output terminal connected to a gate terminal of said semiconductor device and having a supply terminal through which current flows to or from said output terminal in order to force said semiconductor device to an ON state, the improvement comprising:

a capacitor connected between said gate voltage reference terminal of said semiconductor device and said supply terminal of said gate-driving device; and

a filter element connected between said supply terminal of said gate-driving device and a second terminal of said voltage source.

2. A circuit as in claim 1 wherein said gate-driven semiconductor device comprises a MOSFET.

3. A circuit as in claim 1 wherein said filter element comprises a resistor.

4. A circuit as in claim 1 wherein said filter element comprises an inductor.

5. A circuit as in claim 1 wherein said filter element comprises a voltage-limited current source.

7. A circuit as in claim 1 wherein said current sense device includes a first pair of terminals for carrying a current to be sensed and a second pair of terminals for providing a voltage that is proportional to said current to be sensed.

6. A gate charge recovery circuit comprising:

a gate-driven semiconductor device;

a voltage source supplying a gate-driving voltage to said semiconductor device;

a current sense device connected between a gate voltage reference terminal of said semiconductor device and a first terminal of said voltage source;

a gate-driving device having an output terminal connected to a gate terminal of said semiconductor device and having a supply terminal through which current flows to or from said output terminal in order to force said semiconductor device to an ON state;

a capacitor connected between said gate voltage reference terminal of said semiconductor device and said supply terminal of said gate-driving device; and

a filter element connected between said supply terminal of said gate-driving device and a second terminal of said voltage source.

8. A circuit as in claim 6 wherein said gate-driven semiconductor device comprises a MOSFET.

9. A circuit as in claim 6 wherein said filter element comprises a resistor.

10. A circuit as in claim 6 wherein said filter element comprises an inductor.

11. A circuit as in claim 6 wherein said filter element comprises a voltage-limited current source.