Tool/software:
We are struggling with a Qi charging issue where the battery overheats, reaching 48°C after 6 hours of charging, causing swelling. Despite design optimizations, We cannot resolve this.
System Details:
● Receiver IC: BQ51003
● Receiver Coil: WRSR-11R0K-16
● Battery: 650 mAh Li-Po, charging at 3.0 - 4.0V, at 310 mA, 4.0 - 4.2 at 22.5mA.
● Coil inductance(with shield): Ls = 11.8 µH, L's = 13.7 µH.
● Tuning capacitors: C1 = 184.89nF , C2 = 2.17nF
Receiver schematics:
We have experienced Qi receivers that stop working, and need replacement. Which could be a symptom of the issues.
What we have tried so far:
- Adding a shield (3M EM15TP-010).
- Optimizing coil alignment (3 mm distance).
- Precise tuning per TI's guide.
Questions:
1. Is this IC inherently inefficient for low currents (e.g., 25 mA), and causing such high
heating?
2. Could eddy currents cause heating, and how come the shield does not have a significant
effect?
