Hello
Currently we have a device powered by a non-rechargeable LiMnO2 3V Battery that is connected to TPS61291 for 3.3V System power. In Sleep mode, the TPS61291 is in shutdown, because the sleeping MCU can operate down to 1.65V
As an additional function to the device, its possible to mount an additional battery-pack that includes RF-Module for transmitting data. The rechargeable Battery will power the device and the RF module.
Since the battery must be charged, i'm looking for the the following parts:
- Battery Charger, must be suitable for Li-Ion/Li-Poly and LiFe Batteries
- Buck-Converter for Battery charger (if not able to accept 5-12V input)
- Fuel Gauge for Monitoring the Battery Level
- Buck-Converter to reduce the Voltage from the Battery to <= 3.3V
Since space is constrained, less IC's and less design size is a plus. Also the control-interface must be I2C, since there is only two pins left on the main board.
The expected battery amperage would be 2000-3000mAH at 3.6V (Typically 18650 battery type).
Also the Device only needs a lot of current for a short time. For example, the main current will be 800mA@3.3V for a few ms, then around 50mA for approximately 2mins, and after that the device will remain in sleep for some hours (1.5 - 4hs), so the charging current can be really low. When controllable over I2C, the Idea is to charge the battery only, if it has dropped below 50%.
I already did some research:
Charger option: BQ25611D, would accept up to 14V but would need additional switching regulator/LDO for System Power
Gauge: BQ27Z561
Are there any better parts or ideas for this? Any advice on the approach for the solution?
Thank you
