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:
Mar. 16, 2004
Filed:
Nov. 22, 2002
Iilonga Thandiwe, Atlanta, GA (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A circuit and method are disclosed for pulse charging a battery. In this method, the duration of the charging interval of the pulse is governed by the time required to reach an upper threshold voltage. The duration of the non-charging interval is a function of the ionic relaxation of the battery. One preferred embodiment includes a method in which the charging interval is initiated at a voltage that corresponds to the current state of charge of the cell. For example, when the upper threshold is reached, charging is suspended. A microprocessor then determines the state of charge by way of a fuel gauge. If a cell is 70% charged, for instance, an on voltage corresponding to this state of charge is selected. When the cell reaches the on voltage, the charging interval is again initiated. Other alternatives to this method include sensing a slope to determine when ionic relaxation has occurred, and a mathematical approximation of the method.