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. 28, 1999
Filed:
Feb. 03, 1998
Seiko Instruments Inc., , JP;
Abstract
A charge/discharge control circuit cuts off a current path to stop charging of an abnormal secondary cell when the voltage of the secondary cell is less than the threshold voltage of a MOS transistor. The charge/discharge control circuit includes a charge and discharge control circuit for monitoring the voltage of a secondary cell and outputting a signal for controlling the charging and discharging of the secondary cell, a switch circuit for receiving the output signal of the charge and discharge control circuit to stop the charging of the secondary cell in an overcharged or overdischarged state, and a low voltage detecting circuit for receiving the output signal of the charge and discharge control circuit, detecting whether the voltage of the secondary cell is below a predetermined voltage, which is below the overdischarge voltage and which is equal to the threshold voltage of a MOS transistor, and for controlling the switch circuit to prevent charging of the secondary cell if the voltage thereof is below the predetermined voltage.