MP2760 Dying at >17v Supply voltage

Battery Management
1

Hi team,

I am using a MP2760 as a charger board for 3S Li-Ion batteries.

The IC seems to consistently die when the Vin reaches around 16-17V. When the IC dies, it starts emitting a buzzing sound and the IC keeps trying to charge the battery but no current seems to flow.

This is the schematic of my board but it is mostly copied from the datasheet.

Screenshot 2024-10-23 at 18.21.10
Screenshot 2024-10-23 at 18.21.101218×811 56.3 KB

I used a heatsink on the MP2760 and via the GUI it says the junction temperature got to 60C.

Thanks,
Emile

2

I would check the size and current rating of the inductor. The current is limited by this and if its too small for the voltage, it will allow the current to increase above maximum. It may be, you can operate at a low voltage or a high voltage, but not both.

3

Checking the sizing and current rating of the inductor is certainly a constraint that would restrict use cases of this part at higher voltages, which is certainly an important factor to consider for the full operation of this device at recommended ratings as per the datasheet.

However, after reviewing your schematic, there are some things to address that are also worth checking:

  • The IN pin on the datasheet recommends for 4x 10uF ceramic input capacitors. Your schematic only shows 2x 10uF capacitors
  • The SYS pin on the datasheet recommends 4x 22uF ceramic capacitors and 1x 1uF capacitor, it appears you only have 2x 10uF capacitors.
  • The ACOK and INT pins should be pulled up to VCC via an external 10kOhm resistor, while this isn’t shown, please verify this is the case.
  • Verify that the voltage at VCC is 3.6V.

Hopefully these are good starting points in initial debugging.

Best,
Krishan