Semiconductor power switch system

• US 5,672,917 A
• Filed: 09/13/1995
• Issued: 09/30/1997
• Est. Priority Date: 09/27/1994
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nakano, Toshiya
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): KAPLAN, JONATHAN STUART
• Application Number:
  US08/526,270
• Time in Patent Office: 748 Days
• Field of Search: 307/112, 307/113, 307/116, 307/125, 307/126, 307/130, 307/131, 307/139, 307/140
• US Class Current: 307/116
• CPC Class Codes: G01R 31/3277 of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches
• CPC Class Codes: H03K 17/0822 in field-effect transistor switches
• CPC Class Codes: H03K 17/18 Modifications for indicating state of switch

Abstract

A semiconductor power switch system having a control portion and at least one semiconductor power switch unit (PSU) having a self-diagnosis function to simplify the connection lines between the control portion and the PSU. In the PSU, a diagnosing terminal for transmitting an abnormality signal is, by a connection line in the outer portion, connected to an input terminal for receiving a control signal so that the control signal from the control portion to the PSU and the abnormality signal from the PSU to the control portion are communicated through one bidirectional signal transmission line. That is, if an abnormality has taken place, a transistor is turned on so that the level of the bidirectional signal transmission line is fixed to the level of the abnormality signal through the diagnosing terminal and the connection line.

Claims

1. A semiconductor power switch system comprising:

a control portion having an output port and an input port;

at least one semiconductor power switch unit connected to said control portion for controlling supply of electrical power from a power source to a load, in response to a control signal supplied from said output port of said control portion, said semiconductor power switch unit having a self-diagnosis function for detecting an abnormality and, in response, supplying an abnormality signal to the input port of said control portion, said semiconductor power switch unit including

a semiconductor power switch for switching electrical power to said load,

an abnormality detection portion for detecting an abnormality in said semiconductor power switch unit,

a control logic portion connected to said semiconductor power switch and to said abnormality detection portion for controlling said semiconductor power switch in response to the control signal supplied by said control portion and for turning off said semiconductor power switch and generating an internal abnormality detection signal upon detection of an abnormality by said abnormality detection portion,

an abnormality signal generating portion connected to said control logic portion for generating an abnormality signal in response to the internal abnormality detection signal, and

an input/output portion for receiving the control signal supplied by said control portion and for supplying the abnormality signal; and

a bidirectional signal transmission line connected to said output port and said input port of said control portion and to said input/output portion of said semiconductor power switch unit for communicating the control signal and the abnormality signal between said control portion and said semiconductor power switch unit, said input/output portion including an input terminal for receiving the control signal, a diagnosing terminal for supplying the abnormality signal, and a connection line connecting said diagnosing terminal to said input terminal and wherein said abnormality signal generating portion includes a circuit for fixing said bidirectional signal transmission line, through said diagnosing terminal, at a first level in response to generation of the internal abnormality detection signal for communicating the first level to said input port of said control portion.

2. The semiconductor power switch system according to claim 1, wherein said abnormality signal generating portion includes a transistor for connecting said diagnosing terminal to ground when the internal abnormality detection signal has been generated.

3. The semiconductor power switch system according to claim 1, including a second abnormality detection portion connected to the load and to said control logic portion for detecting a short circuit and an open circuit in the load, said control logic circuit turning off said semiconductor power switch and generating the internal abnormality signal upon detection of a short circuit or an open circuit in the load by said second abnormality detection portion.

4. A semiconductor power switch system comprising:

a control portion having an output port and an input port;

at least one semiconductor power switch unit connected to said control portion for controlling supply of electrical power from a power source to a load, in response to a control signal supplied from said output port of said control portion, said semiconductor power switch unit having a self-diagnosis function for detecting an abnormality and, in response, supplying an abnormality signal to the input port of said control portion, said semiconductor power switch unit including

a semiconductor power switch for switching electrical power to said load,

an abnormality detection portion for detecting an abnormality in said semiconductor power switch unit,

a control logic portion connected to said semiconductor power switch and to said abnormality detection portion for controlling said semiconductor power switch in response to the control signal supplied by said control portion and for turning off said semiconductor power switch and generating an internal abnormality detection signal upon detection of an abnormality by said abnormality detection portion,

an abnormality signal generating portion connected to said control logic portion for generating an abnormality signal in response to the internal abnormality detection signal, and

an input/output portion for receiving the control signal supplied by said control portion and for supplying the abnormality signal; and

a bidirectional signal transmission line connected to said output port and said input port of said control portion and to said input/output portion of said semiconductor power switch unit for communicating the control signal and the abnormality signal between said control portion and said semiconductor power switch unit, said input/output portion including an input terminal for receiving the control signal, a diagnosing terminal for supplying the abnormality signal, and a connection line connecting said diagnosing terminal to said input terminal and wherein said abnormality signal generating portion includes a circuit for fixing said bidirectional signal transmission line, through said diagnosing terminal, at a first level in response to generation of the internal abnormality detection signal for communicating the first level to said input port of said control portion, said input/output portion comprising an input/diagnosing terminal for receiving the control signal and for supplying the abnormality signal, and wherein said abnormality signal generating portion comprises a circuit for fixing said bidirectional signal transmission line, through said input/diagnosing terminal, at a first level when the internal abnormality detection signal has been generated for communicating the first level to said input port of said control portion.

5. The semiconductor power switch system according to claim 4, wherein said abnormality signal generating portion includes a transistor for connecting said input/diagnosing terminal to ground when the internal abnormality detection signal has been generated.

6. The semiconductor power switch system according to claim 4, including a second abnormality detection portion connected to the load and to said control logic portion for detecting a short circuit and an open circuit in the load, said control logic circuit turning off said semiconductor power switch and generating the internal abnormality signal upon detection of a short circuit or an open circuit in the load by said second abnormality detection portion.

9. The semiconductor power switch system according to claim 6, including a second abnormality detection portion connected to the load and to said control logic portion for detecting a short circuit and an open circuit in the load, said control logic circuit turning off said semiconductor power switch and generating the internal abnormality signal upon detection of a short circuit or an open circuit in the load by said second abnormality detection portion.

7. A semiconductor power switch wherein comprising:

a control portion having an output port and an input port;

at least one semiconductor power switch unit connected to said control portion for controlling supply of electrical power from a power source to a load in response to a control signal supplied from said output port of said control portion, said semiconductor power switch unit having a self-diagnosis function for detecting an abnormality and, in response, supplying an abnormality signal to the input port of said control portion, said semiconductor power switch unit including

a semiconductor power switch for switching electrical power to said load,

an abnormality detection portion for detecting an abnormality in said semiconductor power switch unit,

a control logic portion connected to said semiconductor power switch and to said abnormality detection portion for controlling said semiconductor power switch in response to the control signal supplied by said control portion and for turning off said semiconductor power switch and generating an internal abnormality detection signal upon detection of an abnormality by said abnormality detection portion,

an abnormality signal generating portion connected to said control logic portion for generating an abnormality signal in response to the internal abnormality detection signal, and

an input/output portion for receiving the control signal supplied by said control portion and for supplying the abnormality signal; and

a bidirectional signal transmission line connected to said output port and said input port of said control portion and to said input/output portion of said semiconductor power switch unit for communicating the control signal and the abnormality signal between said control portion and said semiconductor power switch unit, said input/output portion including an input terminal for receiving the control signal, a diagnosing terminal for supplying the abnormality signal, and a connection line connecting said diagnosing terminal to said input terminal and wherein said abnormality signal generating portion includes a circuit for fixing said bidirectional signal transmission line, through said diagnosing terminal, at a first level in response to generation of the internal abnormality detection signal for communicating the first level to said input port of said control portion, said abnormality signal generating portion generating abnormality signals respectively while said semiconductor power switch unit is operating and while said semiconductor power switch unit is not operating.

8. The semiconductor power switch system according to claim 7, wherein said abnormality signal generating portion includes a first transistor for connecting said input/output portion to ground when the internal abnormality detection signal has been generated while said semiconductor power switch unit is being operated, and a second transistor for connecting said input/output portion to said power source when the internal abnormality detection signal has been generated while said semiconductor power switch unit is not being operated.