Which LiFePo4 charger IC should I use

Good morning to everyone!

I am designing a portable aviation traffic receiver based on raspberry Pi CM4. Most of the time it will be used in small airplanes that may or may not have a USB or USB-C power supply on board. Due to the safety aspects the receiver should be supplied by one LiFePo4 battery.

So basically I am looking for a charger IC that is capable of:

  • Input Voltages between 4-6V (any USB wall-plug adapter)
  • standalone operation (no I²C programming)
  • System out voltage of 5V or better 5.2V or better programmable via resistors (for the CM4 module)
  • deliver min. 1.5A continuous system current
  • powerpath management for seamless switching between battery supply and external supply
  • PD would be very cool! Or any other standard that can charge with more than 500mA

I was browsing for 3 days now to find the correct charger but the amount of products is overwhelming :wink:

The battery I want to use is this one:

They have a “Max. Operating Voltage Range: 2.3V to 3.65V”.
Max. Charge Voltage: 3.65V±50mV

So I need an charger that is able to charge from 2.3V upwards with a normal charge cycle and not slow charge (a LiPo would be deeply discharged at 2.3V )

And that is the point where I am struggeling…

Looking into the DS of the MP2722 it says:

  • Charge voltage configuration range : 3.6V to 4.6 V (so I would not be able to charge the LiFePo4 I mentioned above if the battery voltage would be under 2.3V ?
  • Battery charge voltage regulation does also not match the battery specs

Next one: MP2723:

  • Battery charge voltage regulation (I2C) VBATT_REG Depends on the I2C setting 3.4 to 4.67 V ( so again, no charging possible
    What does that really say? Is that the minimum voltage the battery must have to get charged or is it simply the maximum voltage the charger can charge the battery up to? In my case I would have to configure it 3.65V what would be good!

Which charger is the most suitable for me?
I am grateful for any help…

I suggest looking into the respective IC charge profile. Battery voltage threshold (VBATT) is nominal value of what IC will charge battery up to.

Batt regulation voltage can be configured to specific battery you want to use. As the battery depletes, If Vbatt voltage is below 2.6V battery threshold range, the IC implements trickle charging.

For your application - Please look into MP2623 and MP2633