1500 sets were produced, and about 80 sets could not be charged normally due to 485 IC problem,
The fault phenomena are as follows:
When the output current of power supply product reaches 30A or above,
Adm485 can not communicate, resulting in the output current of the power supply can not continue to adjust the current through adm485 communication,
After the power supply voltage of adm485 is increased to 4V, the communication is normal (at present, the power supply of adm485 is set to 3.3V)
However, after replacing the adm485 with a new adm485 IC, the power supply voltage is reduced to 3V, and the communication is OK
Please ask what causes adm485 to fail to communicate?
The schematic diagram is as follows: