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BQ40Z80EVM-020: EVAL BOARD DAMAGED PROBLEM

Part Number: BQ40Z80EVM-020
Other Parts Discussed in Thread: BQSTUDIO, EV2400, BQ40Z80

Dear Sir,

We are using your TI Eval board for communication with our custom BMS designed for 6S configuration with each cell set to max charge of 4.2V resulting in a pack of 25.2V. We had configured our bms and it is working properly and all protections are also triggering properly. We had 3 TI eval board damaged at our end. We are just connecting SMBC,SMBD and GND of our custom board with J18 connector pin 1, J22 pin 3 and GND with eval VSS.

2 eval board damaged observation:

When our 2 eval board got damaged we debugged our custom BMS and found that TVS diode which were present on SMBC and SMBD diode i.e D8 and D9 with MPN :  TPD1E10B06D , were damaged showing shorting wrt GND. These eventually led SMBC and SMBD shorted with GND. As these lines were connected with our eval board, So eventually our eval board will also get damaged ( If I am correct ).

3rd board damaged Observation:

I
n these case, we were charging our LI-ION battery using a battery charger board i.e LTC4015  with following connections used to connect our bms with battery charger. BMS - pack+,pack-,scl,sda, system present pin -> connected to our battery charger - VCC,GND,SDA,SCL,GND. We have been using above connection and at the same we where observing behaviour of our bms using BQ studio with our eval board. When we disconnected our BMS with battery charger charging current in BQSTUDIO was showing 0  which were correct. But when we connected our bms again with battery charger ( at that time bms was connected with eval board ), suddenly LED indicator on our eval board blinking and it became off. While debugging potential cause of eval board failure, starting with our bms board we found that our bms board was fine it doesn't got damaged. Neither its i2c lines nor anything. But in our eval board, 3V3 is showing shorting with GND i.e its controller U7 IC pin 11,18,50 were showing shorting. I want to know what could have caused issue which damaged our eval board as only 3 lines were connected between our bms and eval board and we just suddenly connected simultaneously our bms with battery charger. I had also attached our bms design schematic for your reference.

Waiting for your reply,

Regards,
Shubham 

3362.BMS.pdf

  • Hi Shubham,

    Regarding the first issue with the diodes, this can occasionally be caused by ESD damage.

    With the second issue, I am confused on the setup. Which TI evaluation board are you using? Is the EV2400 being used?

    Regards,

    Anthony Baldino

  • Hi sir,
    You are right about the first issue. For second case, we are using micro usb connector connected to BQ40Z80 evaluation board and its type A to laptop/pc.
    Other connections are I2C Lines of our custom bms boards with I2C lines of eval board. Hope you got clarification.

    Regards,
    Shubham

  • Hi Shubham,

    Understood, I believe this is where my confusion is coming from.

    But when we connected our bms again with battery charger ( at that time bms was connected with eval board ),

    Looking at this statement, it seems like you are connecting your BMS (which contains bq40z80) to the bq40z80EVM (which also contains a bq40z80 and EV2400 module). If possible, can you please share a picture of how you have each of these situations set up?

    Regards,

    Anthony Baldino

  • Dear Sir,

    As we had discussed about BQ40Z80-EVM board, I have doubt. As while debugging possible cause of our eval board damage. I found that its controller IC U7 with MPN: MSP430F5529IPN  is mostly got damaged. I had one doubt, if we replace the U7 IC with new one on our eval board. Will our eval board will again start working or does there is some software requirement which comes pre-loaded in these IC.

    Regards,
    Shubham

  • Hi Shubham,

    If the U7 IC is replaced on the board, I do not believe it will start working again. This component on the EVM comes preloaded with the necessary software to communicate with the gauge.

    Regards,

    Anthony Baldino

  • Dear Sir,

      Is there any way, I can flash the required software in U7 IC. If yes then from where i can get the code and what tools are required to flash it.

    Regards,
    Shubham 

  • Hi Shubham,

    Yes, it is possible to program the code to the device via the microUSB connection.

    This can be done by using the most recent version of the EV2400 Firmware Updater (currently v0.32) and running it in the command window.

    When running it in the command window, please make sure the -s modifier is added:

    The updater can be found here:

    https://www.ti.com/tool/EV2400

    Regards,

    Anthony Baldino