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BQ76PL455EVM: began overheating

Noel Diaz
Prodigy 80 points
Part Number: BQ76PL455EVM

Hello, 

We have 2 BQ76PL455EVM. The first one began overheating and we disconnected it right away and underneath the part we can see the resistors 1-5 are gone. On the second board light #12 goes on by itself and channel 10-16 lost calibration, the voltage is erratic. 

If you send me some type of  ID #, can we send them in and have them checked out for repair?

Thanks,

Noel

  • 0
    TI__Genius 11480 points
    Noel,

    I am not 100% sure if we do repairs on EVMs or not, but you may consider contacting customer support. More info can be found at this page: www.ti.com/.../faq-returns-and-refunds.page

    Can you tell me a little bit more about your set up and what you were doing when the board started to overheat? Was there any damage to board #2? For the LED to light up, the MOSFET would have to turn on. This means that either the MCU fired up, and turned on EQ12, or possibly that dv/dt coupling through the mosfet parasitic capacitances turned on the FET.
  • 0 in reply to David Wiest Jr
    Prodigy 80 points
    It was the third time we used the board, it was connected in 15s and 4p. The board is not burnt but the resistors 12-16 underneath, are gone.
    Board #2 was working for about a month before the LED light came on by itself and then channels 11-16 became dis-calibrated. We bought a third one, that one has no issues. Since they're not burnt we thought it may be reparable. Please let me know.
  • 0 in reply to Noel Diaz
    TI__Genius 11480 points

    Hi Noah,

    Can you confirm that you shorted the cell 15 connection to the cell 16 connection, as  diagrammed  in Figure 3 of the design considerations app note(found here:http://www.ti.com/lit/an/slua791/slua791.pdf)?

    When board#1 was damaged, where you balancing cells or charging? Or was it during a hot-plug event?

    Similarly, can you describe  the  conditions for board #2 when the channel 12 LED turned on? By discalibrated, I am assuming that you mean the cell accuracy is now poor. Can you verify that the low pass filter components for those pins were not damaged? 

    If we can, I'd like to help you figure out why these problems are happening, so that you do not have problems with the third board.

    As far as repairing it goes, the most help I can offer is the  link I posted earlier, unfortunately. If we do have a return policy for EVM's, I am not aware of it. 

  • 0 in reply to David Wiest Jr
    Prodigy 80 points
    Yes, we don't have 16s at this moment. We joined the 15 with the 16.
    When the board was damaged it was in the hot-plug event.
    From channels 10- -16 the reading is poor, 0.5 v aprox.
  • 0 in reply to Noel Diaz
    TI__Genius 11480 points

    Noel,

    Can  you confirm that  BAT15 is shorted  to both BAT16S and BAT16 on the EVM header? BAT16 is where the TOP pin derives power, and BAT16S is the voltage sense pin. If they are not both  connected, weird things like this could happen.

    Have you checked to see if there was any damage to  the resistors on channels 10-16?

    EDIT: Could you possibly provide a diagram of your cell connections, as well? Sometimes small things are missed that can cause big problems. I just want to check all the bases.