DRIVE CIRCUIT FOR POWER ELEMENT

• US 20100141304A1
• Filed: 07/03/2007
• Published: 06/10/2010
• Est. Priority Date: 07/03/2007
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Miyazaki, Yuji
• Granted Patent: US 8,040,162 B2
• Time in Patent Office: Days
• US Class Current: 327/109
• 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 17/06 Modifications for ensuring a fully conducting state
• CPC Class Codes: H03K 17/567 Circuits characterised by the use of more than one type of semiconductor device, e.g. BIMOS, composite devices such as IGBT
• CPC Class Codes: H03K 2017/066 Maximizing the OFF-resistance instead of minimizing the ON-resistance
• CPC Class Codes: H03K 2217/0045 Full bridges, determining the direction of the current through the load
• CPC Class Codes: H03K 2217/0081 Power supply means, e.g. to the switch driver

Abstract

A driving circuit (1) for an IGBT (10) comprises an H bridge circuit (80) using first to fourth switching elements (Q1-Q4). A control unit (20) switches the states of the switching elements from a first state in which the first and fourth switching elements (Q1, Q4) are set to be in an on state and the second and third switching elements (Q2, Q3) are set to be in an off state to a second state in which the first and fourth switching elements (Q1, Q4) are set to be in an off state and the second and third switching elements (Q2, Q3) are set to be in an on state when receiving an order to make the IGBT (10) transit from an on state to an off state. With the structure of the driving circuit (1) described above, reverse bias can be applied to the IGBT (10) by use of a single power source (15).

Claims

1. A drive circuit for a power element, said power element controlling a main current flowing between first and second main electrodes according to a signal provided to a control electrode, comprising:

a power supply connected between first and second nodes;

a switch matrix circuit configured to connect said control electrode selectively to one of said first and second nodes, and to connect said second main electrode selectively to one of said first and second nodes; and

a control unit for controlling said switch matrix circuit according to an input signal provided for switching said power element between on and off states, wherein

when said input signal changes to switch said power element from the on state to the off state, said control unit switches the state of said switch matrix circuit from a first state for connecting said control electrode to said first node and connecting said second main electrode to said second node to a second state for connecting said control electrode to said second node and connecting said second main electrode to said first node.

2. The drive circuit for the power element according to claim 1, wherein

said switch matrix circuit includes:

a first switch element connected between said control electrode and said first node,

a second switch element connected between said control electrode and said second node,

a third switch element connected between said second main electrode and said first node, and

a fourth switch element connected between said second main electrode and said second node, and

said control unit in said first state turns on said first and fourth switch elements, and turns off said second and third switch elements, and said control unit in said second state turns off said first and fourth switch elements, and turns on said second and third switch elements.

3. The drive circuit for the power element according to claim 2, wherein

said switch matrix circuit further includes a resistance connected in parallel to said first switch element, and

when said input signal changes to switch said power element from the on state to the off state, said control unit temporarily sets the state of said switch matrix circuit to said second state, and thereafter said control unit keeps said third switch element in the on state and turns off said first, second and fourth switch elements.

4. The drive circuit for the power element according to claim 2, wherein

said switch matrix circuit further includes a resistance connected in parallel to said fourth switch element, and

when said input signal changes to switch said power element from the on state to the off state, said control unit temporarily sets the state of said switch matrix circuit to said second state, and thereafter said control unit keeps said second switch element in the on state and turns off said first, third and fourth switch elements.

5. The drive circuit for the power element according to claim 2, wherein

said switch matrix circuit further includes a diode connected in parallel to said third switch element such that said power supply applies a reverse bias to said diode when said fourth switch element is on, and

when said input signal changes to switch said power element from the off state to the on state, said control unit turns on said first switch element and turns off said second, third and fourth switch elements, and thereafter said control unit sets the state of said switch matrix circuit to said first state.

6. The drive circuit for the power element according to claim 2, wherein

said switch matrix circuit further includes a diode connected in parallel to said second switch element such that said power supply applies a reverse bias to said diode when said first switch element is on, and

when said input signal changes to switch said power element from the off state to the on state, said control unit turns on said fourth switch element and turns off said first, second and third switch elements, and thereafter said control unit sets said switch matrix circuit to said first state.

7. The drive circuit for the power element according to claim 2, wherein

said switch matrix circuit further includes a diode connected in parallel to said first switch element such that said power supply applies a reverse bias to said diode when said second switch element is on, and

when said input signal changes to switch said power element from the on state to the off state, said control unit turns on said third switch element and turns off said first, second and fourth switch elements, and thereafter said control unit sets the state of said switch matrix circuit to said second state.

8. The drive circuit for the power element according to claim 2, wherein

said switch matrix circuit further includes a diode connected in parallel to said fourth switch element such that said power supply applies a reverse bias to said diode when said third switch element is on, and

when said input signal changes to switch said power element from the on state to the off state, said control unit turns on said second switch element and turns off said first, third and fourth switch elements, and thereafter said control unit sets the state of said switch matrix circuit to said second state.

9. The drive circuit for the power element according to claim 2, wherein

when said input signal changes to switch said power element from the on state to the off state, said control unit turns on said first and third switch elements and turns off said second and fourth switch elements, and thereafter said control unit sets the state of said switch matrix circuit to said second state.

10. The drive circuit for the power element according to claim 2, wherein

when said input signal changes to switch said power element from the on state to the off state, said control unit turns on said second and fourth switch elements and turns off said first and third switch elements, and thereafter said control unit sets the state of said switch matrix circuit to said second state.

11. The drive circuit for the power element according to claim 2, wherein

when said input signal changes to switch said power element from the off state to the on state, said control unit turns on said first and third switch elements and turns off said second and fourth switch elements, and thereafter said control unit sets the state of said switch matrix circuit to said first state.

12. The drive circuit for the power element according to claim 2, wherein

when said input signal changes to switch said power element from the off state to the on state, said control unit turns on said second and fourth switch elements and turns off said first and third switch elements, and thereafter said control unit sets the state of said switch matrix circuit to said first state.

13. The drive circuit for the power element according to claim 2, further comprising:

a constant voltage unit arranged on at least one of a path extending from said first node through said third switch element to said second main electrode and a path extending from said control electrode through said second switch element to said second node for sharing a voltage between said first and second nodes.

14. The drive circuit for the power element according to claim 1, wherein,

said power element further includes a sense electrode,

a part of said main current flows between said first main electrode and said sense electrode, and

said drive circuit further comprises a current sense resistance connected between said second node and said sense electrode, and a voltage monitoring unit for monitoring a voltage occurring on said current sense resistance.

15. The drive circuit for the power element according to claim 14, further comprising:

a fifth switch element connected in parallel to said current sense resistance, wherein

said control unit turns on said fifth switch element when said input signal changes to switch said power element from the on state to the off state.

16. The drive circuit for the power element according to claim 1, wherein

said power supply is a single DC power supply for supplying a voltage necessary and sufficient for switching said power element to the on state.