• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 64 subscribers
  • Views 1193 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ24105 Burn out

Rajeev
Expert 1355 points
Other Parts Discussed in Thread: BQ24105

Dear all,

We are using BQ24105 for charging 3-cell Li-ion battery pack. 

Now the units are deployed in field. BQ IC is getting burnt at 13(FB pin) and 14th(BAT pin) pins of the IC. 

Total reported burnt IC in field are 30 nos.

At FB pin a resistor divider of 110K and 22K (ground)  are used.

We have been long using the same chargers.

Charger input is 15.10V to 15.30V (MAX)

Thanks,

Rajeev.

  • 0
    TI__Expert 5565 points
    Could you provide a schematic of your application?
  • 0 in reply to Smriti B
    Expert 1355 points

    Hi Smriti,

    Voltage output from adapters is 15.10V to 15.30V  with maximum current of 1A.

    Following is the circuit diagram.

    Regards,

  • 0 in reply to Rajeev
    Prodigy 105 points

    Hi, We are facing a similar issue. The ICs simply burn out. We analysed further and put a scope probe between PGND and OUT pin. IN certain cases we saw pulses as high as 20V and in others it was 16V max. 20V is the max source drain voltage.

    we checked the zener was working. Rajeev, would like to know if you solved your problem; if you did request your inputs or leads.

    Pawan.

  • 0 in reply to Pawandeep Singh
    Prodigy 105 points

    Noticed a very interesting fact. We had two lots of devices- one from an authorised distributor bearing a mark 6EJ in the lot code and another 28W in the lot code. The devices in the 6EJ lot did not give any ringing at PFET turn off point whereas the other lot had a large ringing. changing TVS and inductor values seemed to have no effect on this. Device frequency was 1.1Mhz, well within the 10% tolerance limits defined.

    On the same board when we put the 6EJ series of devices, the peak to peak voltage on the OUT pint remained within 16V max. IN contrast the 28W lot code devices showed a peak to peak voltage of 21V on the OUT pin. Clearly, the internal PFET rating was exceeded. Reducing the I-output had no impact on the Pk to Pk current.

    Further, the pk to Pk on OUT pin is related to the V-IN, which in our case is 14.2V.

    My suggestion- check your source. We are ordering some urgent samples online from a distributor. Will keep you posted on the new lot. 

    But our premise is that we were playing with fakes.

  • 0 in reply to Pawandeep Singh
    Expert 1355 points

    Hi Pawan,

     We have checked input to BQ24105 its bit higher @15.5 volts so we reduced it to 14.2 volts. Then it got solved.