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:
Dec. 07, 1999
Filed:
Nov. 20, 1998
Minoru Sudo, Tokyo, JP;
Takayuki Takashina, Tokyo, JP;
Yoshikazu Kojima, Tokyo, JP;
Sadashi Shimoda, Tokyo, JP;
Hiroshi Mukainakano, Tokyo, JP;
Seiko Instruments Inc., , JP;
Abstract
A charge/discharge control circuit has a voltage detector for detecting a voltage level of a secondary cell, a switch connected in series with the secondary cell, and a control circuit connected in parallel with the voltage detector for receiving and processing an output signal of the voltage detector and controlling an impedance of the switch. The voltage detector, the switch and the control circuit are integrated in a single substrate. In a preferred embodiment, the switch comprises an external connection terminal and a second terminal connected to the secondary cell, a first IGFET connected between the first and second terminals, a second IGFET connectected between the first terminal and a substrate electrode of the first IGFET, and a third IGFET connected between the second terminal and the substrate electrode of the first IGFET.