I am looking for a Li+ DC-DC buck charger for a 300mAh Lithium nickel manganese cobalt oxide coin cell battery. Input is 9-12V, output is 3.3V, load is very small ~8mA but needs to be very efficient. Powerpath device is preferred. BQ25618E appeared to be a good fit although it doesn't seem like it might meet the 4.2V for 3 hours requirement. Here are the requirements from the battery:
- Charge the battery in a temperature range of 0°C to + 45°C. b. Charge the battery at a constant current of 0.5C until 4.20VDC±0.03VDC per cell is attained. Charge rates greater than 1C are NOT recommended. (C: Rated Capacity of Battery) c. Maintain charge voltage at 4.20VDC per cell for 3.0 hours (recommended for maximum capacity). * Use a constant current, constant voltage (CC/CV) lithium-ion (Li+) battery charge controller. * Do not continue to charge battery over specified time.
- Recommended cut-off voltage to 3.0VDC. Recommended maximum discharge rate is 2C at constant current. b. For maximum performance, discharge the battery in a temperature range of –20°C to + 45°C.
