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:
May. 07, 2002
Filed:
Nov. 07, 2001
Applicant:
Inventor:
Shinichi Maeda, Hekinan, JP;
Assignee:
Denso Corporation, Kariya, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02N 2/06 ; H01L 4/109 ;
U.S. Cl.
CPC ...
H02N 2/06 ; H01L 4/109 ;
Abstract
In a driving apparatus for piezo-stacks, a controller repeats switching operation for turning switching elements on/off to thereby attain a determined piezo-actuator voltage. An abnormality detecting circuit determines abnormality of the piezo-stacks by comparing the number of times of charging and the number of times of discharging, or charging/discharging time periods at this occasion with those at normal time.