Compact, 1.5 A Linear Charger for Single-Cell Li+ Battery
An external, low cost, PNP provides the charging current to the battery and an external resistor sets the maximum charge current. A small external capacitor programs the maximum charge time. The controller includes an LED driver to indicate the battery charging status.
Safety features include charging stop mode for battery faults, output overshoot protection, and thermal shutdown. The ADP2291 also features automatic reverse isolation, which does not require an additional blocking diode.
The multistep charge cycle optimizes the battery charging time in a safe manner. It features a trickle charge mode for a deeply discharged cell and a fast charging mode with a maximum current of 1.5 A. The ADP2291 controls the end of charge with a 4.2 V output voltage that is 1% accurate over line and temp-erature. It automatically recharges the battery if the cell voltage drops. When the input supply is removed, the part enters a low current state and reduces the current drawn from the battery to below 1 µA.
The ADP2291 is available in both a small, 8-pin MSOP package and a 3 × 3 mm LFCSP package that is ideally suited for small, portable applications.
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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