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.
Patent No.:
Date of Patent:
Dec. 23, 2003
Filed:
Jul. 22, 2002
Akihiro Yanagisawa, Toyohashi, JP;
Denso Corporation, Kariya, JP;
Abstract
A power supply circuit includes a constant voltage circuit and a timer circuit. The constant voltage circuit generates a constant voltage by regulating a base current of the first transistor via the second transistor. The timer circuit includes a comparator, a delay circuit and an OR circuit. The comparator determines a condition of the IG switch, open or closed. The delay circuit delays inputting an output of the comparator for a predetermined period. The OR circuit outputs a signal to halt the constant voltage generation when the outputs of the comparator and delay circuits indicate that the IG switch is open. The timer circuit is used to continue the constant voltage generation for a predetermined period after the IG switch is opened.