TJA1043：Vbat&Vcc undervoltage detection

[WenChao]

During the test, the following problems were found. Is there any solution?

During the slow rise of the input voltage of Vbat, when Vbat=3.7V, INH outputs 3.6V and maintains 200ms for Vcc under-voltage detection. During this 200ms, the power supply that provides 5V voltage to Vcc is not fully activated (INH signal controls the enable input of 5V power supply), causing the CAN transceiver to enter a sleep mode, and INH output is low. At this time, even if Vbat continues to rise above 5V, the CAN transceiver is still in a sleep mode, the 5V power supply is enabled and turned off, and the power supply cannot be started.

[diazmarin09]

Hello Wen,

I hope all is great with you.

You are correct, I assume the device is detecting an undervoltage time on VCC.

Do you mean slow rise input voltage on VCC? Or, is the same input voltage supplying both VCC and Vbat? Could you please share your schematic?

Have you considered using the pins STB_N, EN or the Wake flag to wake up the device after power up?

Regards,

David