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Title:
OVERCURRENT PROTECTION CIRCUIT AND VOLTAGE GENERATION CIRCUIT AND ELECTRONIC EQUIPMENT USING IT
Document Type and Number:
Japanese Patent JP2006053898
Kind Code:
A
Abstract:

To provide an overcurrent protection circuit capable of speedily detecting an overcurrent condition to limit current without impairing stability of the circuit and to provide a voltage regulator using it.

The voltage generation circuit 100 includes the regulator 10, a first detection circuit 20, and a second detection circuit 30. The first detection circuit 20 includes a first transistor 22, first resistance R1, and an error amplifier 24. The error amplifier 24 performs feedback for limiting output current for a computing amplifier 12 by detecting an overcurrent condition when V1>Vth. The second detection circuit 30 includes a second transistor 32, second resistance R2, and a detection transistor 34. The detection transistor 34 performs feedback for limiting output current for the computing amplifier 12 by turning on when output current Iout exceeds detection threshold value current. Detection threshold value current in the second detection circuit 30 is set to be higher than detection threshold value current in the first detection circuit 20, and its detection operation speed is set to be higher than the detection operation speed of the first detection circuit 20.


Inventors:
KITAGAWA ATSUSHI
Application Number:
JP2005171174A
Publication Date:
February 23, 2006
Filing Date:
June 10, 2005
Export Citation:
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Assignee:
ROHM CO LTD
International Classes:
G05F1/56; G05F3/24; H02H9/02; H03F1/52
Domestic Patent References:
JP2002049430A2002-02-15
JP2004038831A2004-02-05
JP2003173211A2003-06-20
JP2003216252A2003-07-31
JP2001092542A2001-04-06
Attorney, Agent or Firm:
Sakaki Morishita