DRIVING CIRCUIT FOR SWITCHING ELEMENT AND POWER CONVERTER

• US 20120206174A1
• Filed: 10/15/2010
• Published: 08/16/2012
• Est. Priority Date: 10/26/2009
• Status: Active Grant

• Current Assignee: Calsonic Kansei Corporation, Nissan Motor Co., Ltd.
• Original Assignee: Calsonic Kansei Corporation, Nissan Motor Co., Ltd.
• Inventors: Maruyama, Sho, Kikuchi, Yoshiyuki
• Granted Patent: US 8,513,986 B2
• Time in Patent Office: Days
• US Class Current: 327/109
• CPC Class Codes: H03K 17/0828 in composite switches

Abstract

A short-circuit protection circuit (12) configured to protect a switching element from an overcurrent includes: a potential decreasing means for decreasing a potential of a gate terminal when a main circuit current is an overcurrent; a feedback means for performing feedback control on an amount of a decrease in the gate potential caused by the potential decreasing means according to a current amount of the main circuit current; and a phase advancing means for performing phase advance compensation in a feedback loop under the feedback control.

Claims

1. A driving circuit for a switching element comprising:

a control circuit configured to apply a control voltage to a first terminal of a switching element including the first terminal, a second terminal and a third terminal, and thereby to cause a main circuit current to flow in a main circuit between the second terminal and the third terminal; and

a protection circuit configured to protect the switching element when the main circuit current is an overcurrent, wherein

the protection circuit includes;

a potential decreasing unit configured to decrease a potential of the first terminal when the main circuit current is the overcurrent,

a feedback unit configured to perform feedback control on an amount of a decrease in the potential of the first terminal caused by the potential decreasing unit according to a current amount of the main circuit current, and

a phase advancing unit configured to perform phase advance compensation in a feedback loop under the feedback control.

2. The driving circuit for a switching element according to claim 1, wherein the phase advancing unit is set based on a frequency characteristic attributable to a parasitic inductance of the main circuit and a parasitic capacitance of the switching element.

3. The driving circuit for a switching element according to claim 2, wherein the phase advancing unit is set so that a surge voltage generated in the switching element does not exceed a breakdown voltage of the switching element when the main circuit current is the overcurrent.

4. The driving circuit for a switching element according to claim 1, wherein

the potential decreasing unit decreases the potential of the first terminal via a diode by making an NPN transistor conduct based on a voltage generated by a sense resistor connected to a sense terminal branched from part of the third terminal of the switching element,

the feedback unit is formed from a resistor connected to an emitter terminal of the NPN transistor, and

the phase advancing unit is formed from a capacitor which is connected to the resistor on an emitter side of the NPN transistor in parallel.

5. The driving circuit for a switching element according to claim 1, further comprising a cutoff circuit configured to turn off a conduction state of the first terminal of the switching element on condition that an overcurrent state lasts for a predetermined time period.

6. A power converter comprising:

a switching element including a first terminal, a second terminal and a third terminal; and

the driving circuit for a switching element according to claim 1.

7. A driving circuit for a switching element comprising:

a control circuit configured to apply a control voltage to a first terminal of a switching element including the first terminal, a second terminal and a third terminal, and thereby to cause a main circuit current to flow in a main circuit between the second terminal and the third terminal; and

a protection circuit configured to protect the switching element when the main circuit current is an overcurrent, wherein

the protection circuit includes;

potential decreasing means for decreasing a potential of the first terminal when the main circuit current is the overcurrent,

feedback means for performing feedback control on an amount of a decrease in the potential of the first terminal caused by the potential decreasing means according to a current amount of the main circuit current, and

phase advancing means for performing phase advance compensation in a feedback loop under the feedback control.