Patent ID: 7667435

Claim:
A secondary battery protection circuit comprising: an over voltage detector circuit configured to monitor a voltage level of an associated cell of a rechargeable battery and generate a cell-over-voltage (COV) signal in response to a comparison of said voltage level of said cell to an over voltage threshold level; a COV stretch circuit configured to receive said COV signal from said over voltage detector circuit and to maintain said COV signal for a minimum time interval, said stretch circuit further configured to disable a switch via a self-resetting fuse latch if said COV signal remains high for greater than a transient time interval, said switch coupled between said rechargeable battery and a DC power source and capable of moving between conducting and non-conducting states, said switch also responsive to said COV signal to protect said rechargeable battery if said voltage level of said cell is greater than said over voltage threshold level for a time interval less than or equal to said transient time interval.