bq2902

Note: Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to conditions beyond the operational limits for extended periods of time may affect device reliability

The bq2902 is a low-cost charger for rechargeable alkaline batteries such as Renewal® batteries from Rayovac®.
The bq2902 combines sensitive, fullcharge detection for two rechargeable alkaline cells, with a low-battery cut-off for overdischarge protection.

Designed for system integration into a two-cell system, the bq2902 can improve the service life of the rechargeable alkaline cells by properly managing the charge and discharge. The bq2902 requires a voltage limited current source to generate the proper charge pulses for the Renewal® cell. Each cell is individually monitored to ensure full charge without a damaging overcharge.

Charge completion is indicated when the average charge rate falls below approximately 3% of the fast charge rate. A status output is provided to indicate charge in progress, charge complete, or fault indication. The bq2902 avoids over-depleting the battery by using the internal end-of-discharge control circuit. The bq2902 also eliminates the external power switching transistors needed to separately charge individual Renewal cells.

For safety, charging is inhibited if the per-cell voltage of bq2902 is greater than 3.0V during charge (closed-circuit voltage), or if the cell voltage is less than 0.4V (open-circuit voltage).