Hi!
We are using BQ51050B for wireless charging, with configuration according to BQ51050B datasheet. Please see below and illustration in attachment.
In order to achieve safe charging of a battery, with limits, 0 to 50degC, we have used the TI BQ51050B TS calculator tool to arrive at R3=815k, with R1 selected to 200ohm.
We are testing the following two scenarios with a commercial Qi charger.
1) the unit is elevated, from room temperature to 50 degrees C (without charging) -> When we try to charge, it will not start transfer any current to the battery.
2) the unit is put on a charger in room temperature and the temperature is thereafter elevated. -> It continues to charge even if the temperature reaches above 50 degrees C, and even beyond, tested up to 62 degrees. This is where we have an issue.
It should be noted that only the battery itself is held in the temperature chamber, with wires connected to the PCB and charging IC, which is held at room temprature. We have an amp-meter connected to the battery to measure the charging current. The battery has an internal NTC (in the PCM PCB) with parameters: Ro=10k (5%) and BETA=3435.
Would you have any guidance on this issue, it would be highly appreciated.
Kind regards
/CF
