BQ24008: ESD damage at battery terminals

Peter Johansen

Part Number: BQ24008

With reference to my old thread: BQ24008: Sudden change of state and current increase after hours of charging

After 2 days of slow charging (100mA), once again the chip got overheated and damaged at the very same second as I tried to measure the voltage at the battery terminals by use of my handheld multimeter. It seems to me as a kind of ESD issue that brings the IC into a state that simply will damaged the IC if sufficient voltage/current at Vcc is available. Battery voltage 3,7V.

It is not easy to test as it seems to happen seldom. Any other good explanations ?

over 6 years ago

0 Bill Johns over 6 years ago

TI__Guru* 75656 points

Hi

Can you send layout for review?

0 Peter Johansen over 6 years ago in reply to Bill Johns

Intellectual 935 points

Here is the PCB payout without the GND fill visible. The connector at the left is the connection to the battery and the temp-NTC.

0 Bill Johns over 6 years ago in reply to Peter Johansen

TI__Guru* 75656 points

Hi
I have reviews the layout and did not see any problems.
Also reviewed the schematic again the only thing that is out of the ordinary would be 1 ohm input resistor R51.

Does the overheating seem to be a latch up condition or could it be and instability that is causing oscillation?

I have ordered an evaluation module and can do test here, but this will take a few day.

0 Bill Johns over 6 years ago in reply to Bill Johns

TI__Guru* 75656 points

Hi
Any update on this problem are you still seeing the overheating?

0 Peter Johansen over 6 years ago in reply to Bill Johns

Intellectual 935 points

I think we are waiting on each other. We just stopped testing until we could get some further detail from your evaluation. Any news from your side ?

0 Bill Johns over 6 years ago in reply to Peter Johansen

TI__Guru* 75656 points

I will send an update later today.

0 Raheem over 6 years ago in reply to Bill Johns

TI__Mastermind 21590 points

Hello Peter,
I ran some tests in the lab and i was unable to get the device to increase charge current and overheat. Will you be able to add some ESD protection on the OUT to mitigate this?

0 Peter Johansen over 6 years ago in reply to Raheem

Intellectual 935 points

We will make a new PCB including a transorber (TVS) SMAJ15CA across the battery connection just to try. When the PCB is ready and we have made some tests in a few weeks time, we can report our findings.

0 Bill Johns over 6 years ago in reply to Peter Johansen

TI__Guru* 75656 points

Hello
OK to close this post?
If you have more question can reopen this one or post new.

0 Peter Johansen over 6 years ago in reply to Bill Johns

Intellectual 935 points

Ok, Lets close it for now.

Next week we will assemble a new PCB having extra ESD protection. If any news, I will reopen this post or make a new one.

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BQ24008: ESD damage at battery terminals