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. 17, 2012
Filed:
Nov. 18, 2008
Takeshi Yamamoto, Tokyo, JP;
Yoshiharu Shimizu, Aichi, JP;
Takeshi Yamamoto, Tokyo, JP;
Yoshiharu Shimizu, Aichi, JP;
Tamura Corporation, Tokyo, JP;
Makita Corporation, Aichi, JP;
Abstract
An operational amplifier connects to a midpoint between a plurality of serially connected battery cells constituting a secondary battery to provide a charging circuit for inhibiting a charge/discharge current from flowin to the midpoint and an input/output current from flowing from the midpoint to each battery cell. The charging circuit includes excess voltage detectors for detecting whether the voltage is an excess voltage, and a charging controller for determining an overcharge state of each battery cell on the basis of the voltages detected and controlling an ON/OFF of a charging switch. Voltage followers include an operational amplifier, NPN transistor, and the like, connected to a midpoint between a first battery cell and a second battery cell and a midpoint between the second battery cell and the third battery, respectively. The outputs of the voltage followers are configured as the grounds of the excess voltage detectors, respectively.