Features

• Input Supply Voltage Regulation Loop for Peak Power Tracking in (MPPT) Solar Applications
• Wide Input Voltage Range: 4.95V to 32V (40V Abs Max)
• Programmable Charge Rate Up to 2A
• User Selectable Termination: C/10 or On-Board Termination Timer
• Resistor Programmable Float Voltage Up to 14.4V Accommodates Li-Ion/Polymer, LiFePO₄, SLA Chemistries
• No V_IN Blocking Diode Required for Battery Voltages ≤ 4.2V
• 1MHz Fixed Frequency
• 0.5% Float Voltage Reference Accuracy
• 5% Charge Current Accuracy
• 2.5% C/10 Detection Accuracy
• Binary-Coded Open-Collector Status Pins
• Thermally Enhanced 12-Lead 3mm × 3mm DFN and
  MSE Packages

Typical Application

Description

The LT®3652 is a complete monolithic step-down battery charger that operates over a 4.95V to 32V input voltage range. The LT3652 provides a constant-current/ constant-voltage charge characteristic, with maximum charge current externally programmable up to 2A. The charger employs a 3.3V float voltage feedback reference, so any desired battery float voltage up to 14.4V can be programmed with a resistor divider.

The LT3652 employs an input voltage regulation loop, which reduces charge current if the input voltage falls below a programmed level, set with a resistor divider. When the LT3652 is powered by a solar panel, the input regulation loop is used to maintain the panel at peak output power.

The LT3652 can be configured to terminate charging when charge current falls below 1/10 of the programmed maximum (C/10). Once charging is terminated, the LT3652 enters a low-current (85μA) standby mode. An auto-recharge feature starts a new charging cycle if the battery voltage falls 2.5% below the programmed float voltage. The LT3652 also contains a programmable safety timer, used to terminate charging after a desired time is reached. This allows top-off charging at currents less than C/10.