ADP2291-EVAL: Single Li-Ion Battery Charger

The ADP2291 is a constant-current/constant-voltage linear charger for a single-cell, lithium ion battery, requiring just a few components to provide a simple and safe charging system that operates from a wide 4.5 V to 12 V input voltage range. It features an internally controlled, multistep charging cycle that improves battery life.

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.

- Note - Pads for the 'Optional' parts (D2, R6, and Q2) are on the back of the board.