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. 04, 2000
Filed:
Apr. 02, 1998
David M Demuro, Snellville, GA (US);
Motorola, Inc., Schauburg, IL (US);
Abstract
A battery pack (102) comprises a lithium battery cell or cells (112), and is charged by a charger (104). In the event of a failure in the charger, an over-voltage protection circuit (120, 122) normally prevents charging of the battery cell above an over-voltage limit. In the event of a failure in both the charger and the over-voltage protection circuit, a critical voltage protection circuit (124, 126, 128) is provided to render the battery inoperative in a fail safe state. Specifically, a critical voltage control circuit (128) senses the battery voltage reaching the critical voltage level and responds by closing a current shunt switch (126), which draws current from the battery cell or cells through a fuse (124), causing the fuse to open, thus rendering the battery pack inoperative in a fail safe state.