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:
Oct. 29, 2002
Filed:
Aug. 07, 2000
Toru Itabashi, Anjo, JP;
Masahiro Karami, Toyoake, JP;
Denso Corporation, Kariya, JP;
Abstract
A driving apparatus for an electromagnetic valve comprises a conduction control circuit and a current-limit-value setting circuit. The conduction control circuit turns on and off an FET so that a conduction current flowing through the electromagnetic valve has a magnitude equal to a predetermined current limit value while a microcomputer is outputting a driving signal to the conduction control circuit. The predetermined current limit value is set at a first current limit value during a first predetermined period starting at a point of time the microcomputer outputs the driving signal. When the predetermined first period has lapsed, the predetermined current limit value is switched to a second current limit value for a second period. The second limit value is smaller than the first current limit value. A first off-time of the FET for attaining the first current limit value is set to be shorter than a second off-time of the FET for attaining the second current limit value. Alternatively, a first on-time of the FET for attaining the first current limit value is set to be shorter than a second on-time of the FET for attaining the second current limit value in the second period.