Title:
SWITCHING ELEMENT PROTECTIVE CIRCUIT
Document Type and Number:
WIPO Patent Application WO/2005/027326
Kind Code:
A1
Abstract:
A switching element protective circuit comprising a thermistor (11) for detecting the operating temperature of an MOSFET (4), a comparison circuit (12) generating a maintenance signal when an operating temperature detected by the temperature detecting thermistor (11) exceeds a specified level, two avalanche diodes (5, 6) for setting the detection voltage of an overvoltage protective circuit (10), and a transistor (14) connected between the avalanche diodes (5, 6) and the control terminal of the MOSFET (4). When a maintenance signal is generated from the comparison circuit (12), the transistor (14) is turned on to lower the detection voltage of the overvoltage protective circuit (10) and the MOSFET (4) is switched from a high temperature operation down to an operation in a safety operation region. Consequently, the MOSFET (4) can be protected against degradation in characteristics or breakdown during high temperature operation without increasing the size thereof.
Inventors:
IWABUCHI AKIO (JP)
AOKI HIRONORI (JP)
AOKI HIRONORI (JP)
Application Number:
PCT/JP2004/007936
Publication Date:
March 24, 2005
Filing Date:
June 07, 2004
Export Citation:
Assignee:
SANKEN ELECTRIC CO LTD (JP)
IWABUCHI AKIO (JP)
AOKI HIRONORI (JP)
IWABUCHI AKIO (JP)
AOKI HIRONORI (JP)
International Classes:
H02M1/00; H02M1/32; (IPC1-7): H02M1/00
Foreign References:
| JPH09163583A | 1997-06-20 | |||
| EP0749208A2 | 1996-12-18 | |||
| JPH06295591A | 1994-10-21 | |||
| JP2002119044A | 2002-04-19 | |||
| US5465190A | 1995-11-07 | |||
| JP2002151989A | 2002-05-24 |
Attorney, Agent or Firm:
Shimizu, Keiichi (3rd Floor YK Nakameguro Building, 1-5,
Nakameguro 3-chome, Meguro-k, Tokyo 61, JP)
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