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BQ25703A: BQ25703A LODRVE1 MOS broken

Part Number: BQ25703A
Other Parts Discussed in Thread: CSD17551Q3A, CSD17578Q3A,


please help check the schematic.

Input voltage 5V, output voltage 12.6V charge with three 18650 batteries.
During the charging process, the MOS of M6 will be broken.
The M6 MOS model is CSD17578Q3A. The EVM uses CSD17551Q3A.
Please give some suggestion.
  • Hi, Star,

    Thanks for following the BQ25703A EVM  schematic closely, however, I found two places different from the reference design. 

    1) ILIM_HIZ  is connected to CMPOUT. Current configuration allows HIZ operation when battery reaches 12.6V, but 3A current limit is disabled. (Suggest tying CMPOUT to ILIM_HIZ by 10kohm, adding 2Mohm resistor between CMPIN and CMPOUT for hysteresis.)

    2) PGND and GND are connected by a Ferrite Bead. Suggest using a zero-ohm component such as a net-tie copper trace. 

    Is it possible that M6 is damaged without any input current limit? CSD17578 is very similar to CSD17551. I don't think this is an issue.