Maxim Integrated IC MAX1551 / MAX1555
Single-Cell Li+ Battery Chargers
Maxim Integrated IC MAX1551 / MAX1555 dual-input single-cell Li+ battery chargers charge a single-cell Li+ battery from USB and AC adapter sources. These Maxim Integrated battery chargers operate with no external FETs or diodes and accept operating input voltages up to 7V. On-chip thermal limiting simplifies PC board layout and allows optimum charging rate without the thermal limits imposed by worst-case battery and input voltage. When the MAX1551 and MAX1555 thermal limits are reached, the chargers do not shut down but instead progressively reduce charging current. The MAX1551 includes a POK (power OK) output to indicate when input power is present. If either charging source is active, POK goes low. The MAX1555 instead features a CHG output to indicate charging status.