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BQ78350: BQ78350+BQ76930 debugging problem

Annie Liu
Genius 10295 points

Part Number: BQ78350
Other Parts Discussed in Thread: BQSTUDIO, BQ76930, EV2400, TIDA-00792,

Hi Team,

The customer made a new board with BQ78350+BQ76930， and it did not respond to the BQstudio software.Customer would like to know how to make a measurement to determine if the chip is working or enter a certain mode?

Thanks.

  • 0
    TI__Guru* 81035 points

    Hi Annie,

    Here are a few things for them to try:

    Measure the pin voltage on REGOUT of the BQ76930. If this value is low, the device has not come out of Reset and the BQ78350 has no power.

    If the voltage on the REGOUT pin is good, then verify that pullup resistors are installed on the SMBUS pins. They also need to use an EV2400 (or EV2300) to communicate with the device using BQStudio.

    If the voltage on the REGOUT pin is 0V, then they should measure the pins on the BQ76930 to make sure they are seeing proper voltages (VCx pins, CAP1, CAP2, VC5X, BAT, REGIN). If the voltages look good, then they need to send a Boot signal to the device on the TS1 pin (a rising voltage on TS1 brings the device out of reset).

    I hope this helps. If they need more help debugging, this video is a good place to start to make sure everything is connected correctly: https://www.youtube.com/watch?v=B5dsIc2C_xA 

    Best regards,

    Matt

  • 0 in reply to Matt Sunna
    TI__Genius 10295 points

    Hi Matt,

    Thanks for your answer. The pin output voltage is normal, and the VCC and MRST of the BQ78350 are both high. According to the documentation, the SMBus bus is designed for 1M pulldown, but no response. Remove it, change to 4.7K pull-up, still no response. Customer wants to know if there is anywhere else to measure the judgment?

  • 0 in reply to Annie Liu
    TI__Guru* 81035 points

    Hi Annie,

    The SMBus should have pullup resistors. They can use the reference design TIDA-00792 to look at as an example. Have they tried connecting to the device using an EV2400 and BQStudio?

    Matt

  • 0 in reply to Matt Sunna
    TI__Genius 10295 points

    Hi Matt,

    Customer uses the recommended circuit in the BQ78350-R1 chip design document. There is 1M resistor pull-down. If he removes the pull-down, or changes to pull-up 4.7K resistor, it is still no response. And ther is no response using EV2300.

  • 0 in reply to Annie Liu
    TI__Guru* 81035 points

    Hi Annie,

    If they are not able to communicate with the EV2300, something must be wrong on the board. Can you please send me the schematic? 

    One other thing you can check is whether the ground reference for their controller and the BQ78350-R1 is the same. Communication can be disrupted if the protection FETs are open because this disconnects PACK- from the battery ground (BATT-).

    Regards,

    Matt

  • 0 in reply to Matt Sunna
    TI__Guru* 81035 points

    Hi Annie,

    I hope you have been able to resolve this communication issue. I will go ahead and close this thread since I have not heard back from you for a few days. It will automatically reopen if you respond to it.

    Best regards,

    Matt

  • 0 in reply to Matt Sunna
    TI__Genius 10295 points

    Hi Matt,

    Customer didn't give me any feedback. You are able to close this thread. If there is update, I will let you know.

    Thanks.