Patent ID: 6114835
Filing Date: 2000-09-05
Classification: H02J

Abstract:
A multi-cell battery pack charge balancing circuit comprising:a cell voltage comparison subcircuit for connection to a plurality of rechargeable cells, said cell voltage comparison subcircuit having a first voltage threshold and a second voltage threshold and producing cell voltage output signals indicative of a voltage associated with each of said cells exceeding said first voltage threshold and said second voltage threshold;a charge balance trigger connected to said cell voltage comparison subcircuit and operative to receive said cell voltage output signals and to generate a balance signal in response thereto, wherein said balance signal is indicative of the voltage level of at least one of said plurality of cells exceeding said first voltage threshold and at least another of said plurality of cells not exceeding said second voltage threshold;cell balance selection logic connected to said cell voltage comparison subcircuit and to said charge balance trigger, and operative to identify a balance cell and a reference cell from among said plurality of rechargeable cells in response to said balance signal, whereina voltage level of said balance cell exceeds said first voltage threshold, anda voltage level of said reference cell does not exceed said second voltage threshold; anda charge switching subcircuit connected to each of said cells and adapted to electrically connect said balance and said reference cells such that the voltage level of each becomes equal.