Other Parts Discussed in Thread: BQ76952, TIDA-010247
Hello everyone!
We have developed a BMS with 2 BQ76952 ICs, using the TIDA-010247 reference design. We are using LM5163 IC as a buck converter for the supply. We have observed that the buck IC fails sometimes (roughly 1 in 20) during hot plug of the cell voltage connectors. I'm attaching the schematic for reference.
We have made the following observations:
- We are using a 100V part for this. We even captured the voltages on the DSO when the buck converter failed. VIN at the time was around 80V and it overshot a bit like 85V, but never exceeded the 100V limit. The reference design suggests a 120V part of the same family. We figured that this is because the design is intended to be used with higher voltage applications. Our max voltage will never exceed 85V, should we also use the 120V variant?
- Sometimes when the buck fails, the ferrite bead on the VIN pin also blows up.
- TVS diodes on the VIN input don't fail, suggesting that the overvoltage conditions didn't occur. Is that right?
- The issue is not consistent and only happens rarely. But is recurring enough to be a problem for us when we deploy our BMS in the market.
Thanks in advance!