High-Voltage 950mA Lithium Battery Charger Automatically Selects Between USB or Wall Adapter

Linear Technology Corporation introduces the LTC4075HVX, a standalone dual-input linear battery charger that efficiently manages charging single-cell Li-Ion/Polymer batteries from two separate power sources: a wall adapter and USB. Using a constant-current/constant-voltage algorithm, the charger can deliver up to 950mA of charge current from a wall adapter supply, or up to 850mA of charge current from a USB supply and automatically sense the presence of voltage at each input. The final float voltage accuracy is ±0.6% in either case. The LTC4075HVX provides protection up to 22V(max) on both inputs. If the selected power source exceeds the overvoltage lockout limit, the LTC4075HVX will stop charging. The LTC4075HVX disables the trickle charge function, benefiting systems requiring higher charge current during low battery conditions. Applications include PDAs, MP3 players, lightweight portable medical and test equipment and large color screen cell phones.

The LTC4075HVX is equipped with a patented thermal regulation scheme that maximizes the charging rate without the risk of overheating. The device is extremely flexible, enabling programmability via a single resistor of wall adapter supply charge current, USB supply charge current and charge termination current. As a standalone charger, the LTC4075HVX simplifies design, since no external microprocessor is required for charge termination. The IC features undervoltage lockout, automatic recharge, charge status and "power present" status indication.

The LTC4075HVX draws