BQ79616-Q1: Disconnect of BAT from BQ79616

And what happens, if only LDOIN is disconnected? Is there some current flow?

Hi Alexander,

thanks for your response. After disconnecting BAT and LDOIN I observes a small hole in the BQ :). Its not a shortcut, if BAT is 0 and VC16 is 60V? I will repeat the test to be sure that no other effect caused this. By disconnecting LDOIN I observed that the shutdown current increased from 0,015mA to 0,35mA. I have also observed, that the TX pin supplies the digital isolator (also in shutdown). Maybe this effect is causing the higher shutdown current. What do you think? I will disconnect TX from the isolator to check if this is the cause.

BR

Christian

Christian,

A physical hole in the device? Do you have the cap between BAT and VC16? And you are floating BAT, not shorting to 0V. I would expect that that would keep the voltages close enough together to avoid damage. In any case, it does sound like there has been damage here.

With regards to the TX pin and isolator, this is something we have seen in the past. Depending on what is connected, we have seen current drawn out of this pin in shutdown.

Hi Alexander,

yes, a physikal hole. No there is no cap. I can't find this information neither in der datasheet nor in the design recommendation. I will repeat the test with this cap. Thank you.

BR

Christian

Christian,

We do have this component listed is a few places. Below is a snapshot from the datasheet Fig 10-11. I agree that it is very easy to miss - especially since we have several diagrams that don't show it (since they focus on specific aspects of the design)