BQ24171: Failure in Switching

Pang

Part Number: BQ24171

Hi Ti,

Currently is using this part in design found that BQ24171 not switching after a few cycles of charge/discharge cycles.

Failure symptom:

SW pin no switching signal and charger output is not regulated to 4.2V but ~10.5V with 12Vin. (RT is terminated with 10k)

Please help to advise.

over 7 years ago

0 Steven Bangdiwala over 7 years ago

TI__Expert 8690 points

Hi,

Are you using the EVM? Or did you make your own design? Most likely the high side FET got damaged, could be from ESD damage.

Regards,
Steven

0 Pang over 7 years ago in reply to Steven Bangdiwala

Expert 2415 points

Hi Steven,

It's on my own design board. I happens like 30pcs among the 100pcs but not all of it.

0 Steven Bangdiwala over 7 years ago in reply to Pang

TI__Expert 8690 points

Hi,

It might be ESD damage. How is the IC soldered on your board? Do you use metal tweezers to handle the IC? Is there any sort of testing fixture you use on the board before verifying if it failed?

Also, could you provide your schematic?

Regards,
Steven

0 Pang over 7 years ago in reply to Steven Bangdiwala

Expert 2415 points

Hi,

It's using SMT placement machine. I will need to provide you the schematic privately. Please advise email.

0 Steven Bangdiwala over 7 years ago in reply to Pang

TI__Expert 8690 points

I sent you a message.

Regards,
Steven

0 Steven Bangdiwala over 7 years ago in reply to Steven Bangdiwala

TI__Expert 8690 points

I do not see anything wrong with the schematic on the charger portion. Although, I do notice that there is no diode OR connecting VIN and VBAT to AVCC, there is only one diode from VBAT to AVCC. This may be problematic if you don't want any power connected to VIN if there is no adapter..

I don't know what is connected to P+ and 4V, which are at the output. Something else on the system may be causing you this problem.

I know this would be a little tedious, but on the bad unit you could provide voltage for each pin, also provide a waveform for PVCC, AVCC, SRN, VREF and SW with battery and without battery.

Regards,
Steven

0 Pang over 7 years ago in reply to Steven Bangdiwala

Expert 2415 points

Hi Steven,

Kindly please find the attached data. On the waveform sharing, can you share me your email as there is few data to attach.

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BQ24171: Failure in Switching