Gate driving circuit

• US 8,427,225 B2
• Filed: 09/03/2008
• Issued: 04/23/2013
• Est. Priority Date: 10/02/2007
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Nakatake, Hiroshi, Fuku, Masaru, Okuda, Tatsuya, Tsunoda, Yoshikazu
• Primary Examiner(s): Donovan, Lincoln
• Assistant Examiner(s): Cole, Brandon S
• Application Number:
  US12/681,515
• Publication Number:
  US 20100213989A1
• Time in Patent Office: 1,693 Days
• Field of Search: 327108-112, 327/170, 327374-377, 327/379, 327/284, 326 21- 24, 326 82- 84, 326/89
• US Class Current: 327/427
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H03K 17/0406 in composite switches
• CPC Class Codes: H03K 17/0412 by measures taken in the control circuit
• CPC Class Codes: H03K 17/162 without feedback from the output circuit to the control circuit
• CPC Class Codes: H03K 2217/0036 Means reducing energy consumption

Abstract

To obtain a gate driving circuit in which rising of a constant current of a constant current circuit is fast and power saving is achieved, the gate driving circuit includes: a constant current driving circuit (28) for supplying a constant current; a gate terminal of a power semiconductor element (1), which is connected to an output terminal of the constant current driving circuit; a comparator (22) for comparing a voltage at the gate terminal with a predetermined voltage value and outputting a signal indicating that the voltage is higher than the predetermined voltage value; and a driving control section (20) for increasing a current from the constant current driving circuit in response to a signal for turning on the power semiconductor element, and reducing the current from the constant current driving circuit in response to the signal from the comparator.

Claims

1. A gate driving circuit for performing switching control on a power semiconductor element which has a gate, said gate driving circuit comprising:

a constant current driving circuit which is connected to a positive power source for charging said gate to let said power semiconductor element be turned on;

a gate terminal connected to said gate, which is connected to an output terminal of said constant current driving circuit;

an auxiliary current supply circuit which is connected to the output terminal of said constant current driving circuit or connected to said gate terminal;

a first switch which is provided in said constant current driving circuit, wherein said constant current driving circuit comprises a plurality of resistors connected in series and said first switch is connected in parallel to one of said plurality of resistors, or provided outside of said constant current driving circuit, wherein a first terminal of said first switch is connected to said positive power source and a second terminal of said first switch is connected to said gate terminal;

a second switch for turning on and off said auxiliary current supply circuit; and

a driving control section that outputs signals for turning on and off said first switch and said second switch.

2. The gate driving circuit according to claim 1, wherein said driving control section turns on said second switch to supply a current output from said constant current driving circuit to said auxiliary current supply circuit, and turns on said first switch and turns off said second switch after the current supplied to said auxiliary current supply circuit is held to a predetermined current value, to thereby turn the current output from said constant current driving circuit to flow into said gate terminal.

3. The gate driving circuit according to claim 2, further comprising:

a comparator for comparing a voltage at said gate terminal with a first set voltage value and outputting a signal indicating that the voltage is higher than the first set voltage value,

wherein said driving control section increases the current from said constant current driving circuit in response to a signal for turning on said power semiconductor element, and reduces the current from said constant current driving circuit in response to the signal from said comparator.

4. The gate driving circuit according to claim 3, wherein:

said constant current driving circuit further comprises a switch for adjusting a resistance value to vary the current from said constant current driving circuit; and

said driving control section turns on and off said switch to vary the current from said constant current driving circuit.

5. The gate driving circuit according to claim 4, wherein said switch comprises an on-off switch connected in parallel to series resistors of said constant current driving circuit.

6. The gate driving circuit according to claim 2, further comprising:

a comparison section for comparing a voltage at said gate terminal with a first set voltage value, outputting a first signal when the voltage is higher than the first set voltage value, comparing the voltage at said gate terminal with a second set voltage value lower than the first set voltage value, and outputting a second signal when the voltage is lower than the second set voltage value,

wherein said driving control section reduces the current from said constant current driving circuit in response to the first signal, and increases the current from said constant current driving circuit in response to the second signal.

7. The gate driving circuit according to claim 6, wherein:

said constant current driving circuit further comprises a switch for adjusting a resistance value to vary the current from said constant current driving circuit; and

said driving control section turns on and off said switch to vary the current from said constant current driving circuit.

8. The gate driving circuit according to claim 7, wherein said switch comprises an on-off switch connected in parallel to series resistors of said constant current driving circuit.

9. The gate driving circuit according to claim 2, wherein said constant current driving circuit comprises a current mirror circuit and a constant current circuit for driving said current mirror circuit.

10. The gate driving circuit according to claim 1, wherein said constant current driving circuit comprises a current mirror circuit and a constant current circuit for driving said current mirror circuit.

11. The gate driving circuit according to claim 1, wherein said auxiliary current supply circuit includes at least one resistor.

12. The gate driving circuit according to claim 1, wherein said second switch is located between said gate terminal and ground.

13. The gate driving circuit according to claim 1, wherein said first switch is provided between said output terminal and said gate terminal.