The LT3652 accepts a wide range of inputs from 4.95V to 32V with a 40V absolute maximum rating for added system margin. The input voltage regulation loop also allows optimized charging from poorly regulated sources where the input can collapse under overcurrent conditions. It charges a variety of battery pack configurations, including 1 to 3 Li-Ion / Polymer cells in series, 1 to 4 LiFePO4 (Lithium Iron Phosphate) cells in series and sealed lead acid (SLA) batteries up to 14.4V. Applications include solar powered systems, 12V to 24V automotive equipment and battery chargers.
The LT3652’s charge current is programmable up to 2A. This stand-alone battery charger requires no external microcontroller, and features user-selectable termination, including C/10 or an onboard timer. The device’s 1MHz fixed switching frequency enables small solution sizes. Float voltage feedback accuracy is specified at ±0.5%, charge current accuracy is ±5% and C/10 detection accuracy is ±2.5%. Once charging is terminated, the LT3652 automatically enters a low current standby mode, which reduces the input supply current to 85uA. In shutdown, the input bias current is reduced to 15uA. For autonomous charge control, an auto-recharge feature starts a new charging cycle if the battery voltage falls 2.5% below the programmed float voltage.