lt3650The LT3650 circuit is a monolithic two-cell Li-Ion/ Polymer battery charger that operates from 9V to 32V input voltage range (11.5V minimum start-up voltage). The LT3650 si produced by Linear Technology and provides a constant-current/constant-voltage charge characteristic, with maximum charge current externally programmable up to 2A, set using an external current sense resistor.

The LT3650-8.2 does not require external high-precision resistors to set the float voltage, further saving cost and space. Applications include industrial handheld instruments, 12V to 24V automotive and heavy equipment, desktop cradle chargers and small notebook or tablet computers.

lt3650 package

The LT3650 Li-Ion battery charger high operating frequency of 1MHz and current mode architecture allow the use of small inductors and capacitors, minimizing noise and filtering needs. Final float voltage accuracy is specified at ±0.5%, charge current accuracy is ±5% and C/10 detection accuracy is ±2.5%. Once charging is terminated, the LT3650-8.2 automatically enters a low current standby mode that reduces the input supply current to 85uA. In shutdown, the input bias current is reduced to 15uA.

The LT3650-8.2 maximizes battery life during all non-charging periods, draining less than 1uA from the battery. For safety and autonomous charge control, the LT3650-8.2 includes features such as automatic restart and preconditioning, a thermistor input for temperature-qualified charging, programmable input current limit, bad battery detection and binary coded status output pins.

LT 3650 Li Ion battery charger features

  • Wide Input Voltage Range: 9V to 32V (40V Absolute Maximum)
  • Programmable Charge Current: Up to 2A
  • User-Selectable Termination: C/10 or Onboard Termination Timer
  • Programmable Input Current Limit
  • 1MHz Fixed Frequency
  • Average Current Mode Control
  • 0.5% Float Voltage Accuracy (8.2V)
  • 2.5% C/10 Detection Accuracy
  • NTC Resistor Temperature Monitor
  • Auto-Recharge at 97.5% Float Voltage
  • Bad Battery Detection with Auto-Reset
  • Binary Coded Open-Collector Status Pins

LT3650 Li Ion charger applications

  • Industrial Handheld Instruments
  • 12V to 24V Automotive and Heavy Equipment
  • Desktop Cradle Chargers
  • Notebook Computers

LT3650 charger circuit diagram

lt3650 li-ion battery charger schematic