Protection circuit

• US 20040228059A1
• Filed: 02/13/2004
• Published: 11/18/2004
• Est. Priority Date: 02/14/2003
• Status: Active Grant

• Current Assignee: Autonetworks Technologies, Ltd. (Sumitomo Corporation), Sumitomo Electric Industries Limited (Sumitomo Corporation), Sumitomo Wiring Systems Limited (Sumitomo Corporation)
• Original Assignee: Autonetworks Technologies, Ltd. (Sumitomo Corporation), Sumitomo Electric Industries Limited (Sumitomo Corporation), Sumitomo Wiring Systems Limited (Sumitomo Corporation)
• Inventors: Isshiki, Isao, Mayama, Shuji
• Granted Patent: US 7,031,129 B2
• Time in Patent Office: Days
• US Class Current: 361/100
• CPC Class Codes: H03K 17/08122 in field-effect transistor switches
• CPC Class Codes: H03K 17/0822 in field-effect transistor switches

Abstract

A protection circuit, to be provided for a circuit arrangement having an inductive load and an FET as an N-channel MOS transistor provided upstream of the load with respect to a flow of power current, the FET controlling an energization state of the load, the protection circuit includes a first connection changer interposed on a connection line between a gate of the FET and a gate drive voltage supply source, the first connection changer changing a connection state between a first connection state in which the gate is connected to the gate drive voltage supply and a second connection state in which the gate is connected to a ground.

Claims

1. A protection circuit, to be provided for a circuit arrangement having an inductive load and an FET as an N-channel MOS transistor provided upstream of the load with respect to a flow of power current, the FET controlling an energization state of the load, the protection circuit comprising:

a first connection changer interposed on a connection line between a gate of the FET and a gate drive voltage supply source, the first connection changer changing a connection state between a first connection state in which the gate is connected to the gate drive voltage supply and a second connection state in which the gate is connected to a ground.

2. The protection circuit according to claim 1, further comprising:

a first resistor interposed between the gate and a source of the FET; and

a second resistor interposed between the gate and the first connection changer or between the first connection changer and the ground.

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

a second connection changer interposed on a connection line between the gate and the source of the FET, the second connection changer for connecting and disconnecting the connection line;

wherein the first resistor is interposed on the connection line.

4. A protection circuit, to be provided for a circuit arrangement having an inductive load and an FET as an N-channel MOS transistor provided upstream of the load with respect to a flow of power current, the FET controlling an energization state of the load, the protection circuit comprising:

a first connection changer interposed between a portion on a first connection line and a ground, the first connection changer connecting and disconnecting between the portion and the ground;

wherein the first connection line connects a gate of the FET and a gate drive voltage supply source.

5. The protection circuit according to claim 4, further comprising:

a first resistor interposed on a second connection line between the gate and a source of the FET; and

a second resistor interposed on a route from the gate to the ground through the first connection line and the connection changer.

6. The protection circuit according to claim 5, further comprising:

a second connection changer interposed on the second connection line between the gate and the source of the FET, the second connection changer connecting and disconnecting the second connection line;

wherein the first resistor is interposed in the second connection line.

7. A protection circuit, to be provided for a circuit arrangement having an inductive load and an FET as a P-channel MOS transistor, the FET for controlling an energization state of the load, the protection circuit comprising:

a connection changer interposed on a connection line between a gate of the FET and a ground, the connection changer changing a connection state between a first connection state in which the gate is connected to the ground and a second connection state in which the gate is connected to a source of the FET;

a first resistor interposed between the gate of the FET and the connection changer or between the connection changer and the source of the FET; and

a second resistor interposed between the gate and the drain of the FET.

8. A protection circuit, to be provided for a circuit arrangement having an inductive load and an FET as a P-channel MOS transistor, the FET controlling an energization state of the load, the protection circuit comprising:

a connection changer interposed between a portion, on a connection line between a gate and a source of the FET, and a ground, the connection changer connecting and disconnecting between the portion and the ground;

a first resistor interposed on a route of from the gate of the FET to the source thereof through the connection line; and

a second resistor interposed between the gate and a drain of the FET.

9. A protection circuit, to be provided for a circuit arrangement having an inductive load and an IGBT provided upstream of the load with respect to a flow of power current, the IGBT controlling an energization state of the load, the protection circuit comprising:

a connection changer interposed on a connection line between a gate of the IGBT and a gate drive voltage supply source, the connection changer changing a connection state between a first connection state in which the gate is connected to the gate drive voltage supply and a second connection state in which the gate is connected to a ground.

10. The protection circuit according to claim 9, further comprising:

a first resistor interposed between the gate and an emitter of the IGBT; and

a second resistor interposed between the gate of the IGBT and the connection changer or between the connection changer and the ground.

11. A protection circuit, to be provided for a circuit arrangement having an inductive load and an IGBT provided upstream of the load with respect to a flow of power current, the IGBT controlling an energization state of the load, the protection circuit comprising:

a connection changer interposed between a portion on a connection line and a ground, the connection changer connecting and disconnecting between the portion and the ground;

wherein the connection line connects a gate of the IGBT and a gate drive voltage supply source.

12. The protection circuit according to claim 11, further comprising:

a first resistor interposed between the gate and an emitter of the IGBT; and

a second resistor interposed on a route from the gate of the IGBT to the ground through the connection line and the connection changer.