Buck Battery-Charger IC Holds Solar Panels At Peak Output

The LT3652, a monolithic buck battery-charger IC, features an input-voltage regulation loop that controls charge current to hold the input voltage at a programmed level. When the LT3652 is connected to a solar panel, the input regulation loop maintains the panel at peak output power. The LT3652 accepts a wide range of inputs from 4.95 V to 32 V with a 40-V 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 one to three Li-Ion / Polymer cells in series, one to four LiFePO₄ (Lithium Iron Phosphate) cells in series and sealed lead acid (SLA) batteries up to 14.4 V. Applications include solar powered systems, 12-V to 24-V automotive equipment and battery chargers. The IC’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. Float voltage feedback accuracy is specified at ±0.5%, charge current accuracy is ±5%, and C/10 detection accuracy is ±2.5%. The LT3652 comes in a low-profile (0.75-mm), 12-pin, 3-mm x 3-mm DFN package. Pricing starts at $3.05 in lots of 1000. LINEAR TECHNOLOGY CORP., Milpitas, CA. (408) 432-1900.