Linear Technology Corp. (LTC, Milpitas, CA) introduced its new LTC4055, a single-IC, autonomous power manager and battery charger for USB and USB devices. The LTC4055 provides power to the USB peripheral device and charges the peripheral’s single-cell, lithium-ion battery from the USB VBUS, or a wall adapter power supply if the adapter is present.
The LTC4055 automatically reduces battery charge current as the system load current increases. To ensure that a fully charged battery remains fresh when the bus is connected, the IC directs power to the load through the USB bus rather than extracting power from the battery. Once the power source is removed, current flows from the battery to the load through an internal low loss “ideal” diode, minimizing voltage drop and power dissipation.
The LTC4055’s float voltage is preset at 4.2 V with guaranteed 0.8-percent accuracy from 0 °C to 85 °C. For battery pre-conditioning and qualification, fully discharged cells are automatically trickle-charged at 10 percent of the programmed current until the cell voltage exceeds 2.8 V. The LTC4055 is housed in a 4 mm x 4 mm QFN package with a 0.8 mm profile.
The LTC4055 is guaranteed for operation from -40 °C to +85 °C. Pricing for 1,000-piece quantities starts at $2.20 each.