MAX1555
Description
The MAX1551/MAX1555 charge a single-cell lithium-ion (Li+) battery from both USB and AC adapter sources. They 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/MAX1555 thermal limits are reached, the chargers do not shut down, but progressively reduce charging current. The MAX1551 includes a POK 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. With USB connected, but without DC power, charge current is set to 100m A (max). This allows charging from both powered and unpowered USB hubs with no port munication required. When DC power is connected, charging current is set at 280m A (typ). No input-blocking diodes are required to prevent battery...
