MAX1908 battery charger

Maxim's MAX1908 is a highly integrated, multichemistry battery charger that simplifies the construction of chargers.

It charges two to four lithium ion (Li+) series cells, providing 4 A of current. When charging, this device automatically transitions from regulating current to regulating voltage.

Programmed by the host or hardwired, it uses analog inputs to control charge current and voltage. Its buck topology with synchronous rectification achieves high efficiency. The charger's outputs monitor battery charging current, the presence of an AC adapter, and the currents drawn from it.

It allows programming of the maximum current drawn from the adapter. This avoids overloading it when simultaneously supplying the load and the battery charger. The device provides 0.5% accurate battery voltage regulation, which extends battery capacity and minimises charging times.

Additionally, it provides control of charger parameters. With 5% accurate charge current regulation and adapter current limiting using 15 mohms resistors, hot spots in the system are eliminated.