High Voltage 2A Battery Charger Matches Solar Cell Peak Power Tracking with Simple Control Loop

According to Steve Pietkiewicz, Vice President and General Manager of Power Products, “The LT3652HV, with its increased output voltage capability, is a welcome addition to our growing line of solar input compatible battery charger ICs. Like the LT3652, its simple but unique input voltage regulation loop circuitry delivers virtually the same charging efficiency as more complex and expensive Maximum Peak Power Tracking (MPPT) techniques.”

The LT3652HV accepts a wide range of inputs from 4.95V to 34V 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 4 Li-Ion / Polymer cells in series, 1 to 5 LiFePO4 (Lithium Iron Phosphate) cells in series and sealed lead acid (SLA) batteries up to 18V. Applications include solar-powered systems, 12V to 24V automotive equipment and battery chargers.

The LT3652HV'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 LT3652HV automatically enters a low current standby mode, which reduces the input supply current to 85µA. In shutdown, the input bias current is reduced to 15µA. 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.