Intersil is offering a battery charger which can detect auxiliary and external power connections in mobile devices.

The ISL9222A is a high input, single cell, Li-Ion battery charger IC that incorporates a charger and digital logic (OR gate) into a single chip.

It accepts an input voltage up to 28V, but is disabled when the input voltage exceeds the overvoltage protection threshold (typically 7.2V) in order to prevent excessive power dissipation. The 28V rating eliminates the overvoltage protection circuit required with a low input voltage charger. 

The charge current is user-programmable with an external resistor. When the battery voltage is lower than 2.55V, the charger preconditions the battery with 20% of the programmed charge current.

The ISL9222A also features a thermal fold-back function that protects the charger from over-temperature conditions. Voltage accuracy is 1%.

More information: www.intersil.com