Two MAX17703 on one PCB for one battery each do not work

Question

Dears,

I have one PCB with two MAX17703 for one battery each (Lipo 6s/12Ah). If I connect only battery 1 and switch on the charging power supply (30V/30A), it works fine. If I connect only battery 2 and switch on the charger, it also works. But if I connect both batteries and switch on the charger, only the first battery charges. I have built 4 boards and all of them have the same issue.
The only thing the two MAX17703 share is the charging power supply, everything else is separate.

I really have no idea why it doesn't work. Can anyone help me or give me a tip?

Thank you very much.
Doenis

Doenis · Answer

I have found out. For those who have two or more MAX17703 with the same DCIN: You need to decouple EN/UVLO(pin17), DCIN(pin18) and VIN(pin20) from the high current path with a shottky.

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Two MAX17703 on one PCB for one battery each do not work