The LTC1734 is a low-cost, single-cell, constant-current/constant-voltage Li-Ion battery charger controller. It is a small and low-cost charger for single-cell lithium-ion batteries. It comes in 4.1V and 4.2V versions with 1% accuracy. Constant current can be set using an external resistor, and charge current can be monitored via voltage. It has automatic sleep mode and manual shutdown features.
The LTC1734 is a low‑cost, single‑cell lithium‑ion battery charger controller offered in 4.1 V and 4.2 V versions. It provides constant‑current/constant‑voltage charging with programmable current from 200 mA to 700 mA, manual shutdown, and an automatic sleep mode that draws near‑zero current when input power is removed.
The device is supplied in a 1 mm ThinSOT (SOT‑23) package and includes an internal current‑sense resistor, undervoltage lockout, over‑current and over‑temperature protection, and a PROG pin that both programs the charge current and allows the charge current to be monitored by a microcontroller.
| Supply Voltage (VCC) Range | 0.3 V to 9 V |
|---|---|
| Input Voltage (BAT, PROG) Range | 0.3 V to (VCC + 0.3 V) |
| Maximum Output Current (ISENSE) | 900 mA |
| Programmable Charge Current | 200 mA to 700 mA |
Manual shutdown is accomplished by floating the programming resistor while removing input power, which puts the LTC1734 into a sleep mode with near‑zero battery drain.
The voltage on the PROG pin is proportional to the charge current, so a microcontroller can read this voltage with an ADC to determine the current.
The LTC1734 is available in 4.1 V and 4.2 V preset voltage versions.
The device can deliver up to 900 mA of output current.