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:
Apr. 25, 2006
Filed:
Feb. 19, 2004
Yasuhiro Fukagawa, Obu, JP;
Yasuyuki Sakakibara, Nishio, JP;
Eiji Takemoto, Obu, JP;
DENSO Corporation, Kariya, JP;
Abstract
A piezo actuator drive circuit comprises a charging path for charging a piezo stack that can be driven by being charged and discharged, an arithmetic circuit for calculating the charging amount for the piezo stack, and a driving control circuit for comparing the calculated charging amount and a target charging amount and correcting the charging amount during the next charging process according to the difference between the compared charging amounts. A charging current flowing through the piezo stack and a charging voltage applied to it may be measured during a charging process. It is preferable that the calculated charging amount be the amount of energy that is the result of the time quadrature of the product of the measured current and voltage.