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:
Sep. 06, 1994
Filed:
Sep. 17, 1992
Nobuo Shiojima, Tokyo, JP;
Toshiba Battery Co., Ltd., Tokyo, JP;
Abstract
A reference voltage generating circuit generates a reference voltage Vz, which is a predetermined level different from the potential of one of the terminals of a secondary battery. A minute voltage change extracting circuit comprises a operational amplifier to which the reference voltage Vz is input, a capacitor C, and a resistor R. The minute voltage change extracting circuit extracts minute voltage changes, which appear in the last stage of a process of charging the secondary battery and have components of a frequency higher than a change in a terminal voltage corresponding to the amount of charge, as output signals which vary around the reference voltage Vz. The output signals are shaped into pulse signals by a shaping circuit. The pulse signals are counted by a counter circuit. When the count reaches a predetermined value, charging of the secondary battery is controlled.