The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Nov. 18, 2003

Filed:

Apr. 15, 2002
Applicant:
Inventor:

Takahisa Koyasu, Chita-gun, JP;

Assignee:

Denso Corporation, Kariya, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02H 5/04 ;
U.S. Cl.
CPC ...
H02H 5/04 ;
Abstract

A supply current is supplied to an error detection circuit for detecting an error condition of an IC of the power supply circuit such as an overheat detection circuit only when the detection current of the power transistor of the power supply circuit is higher than a reference. Moreover, a supply current to the constant current source is supplied only when the detection current of the power transistor is higher than the reference to suppress the power consumption. Thus, suppression of the power consumption in the battery backup operation for a RAM during ignition off condition is provided. The current detection of the power transistor of the power supply circuit is detected with a series resistor or a multi-collector transistor.


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