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BQ41Z90EVM: CFET & DFET don't turn on

Tobias Jung
Prodigy 80 points
Part Number: BQ41Z90EVM

Tool/software:

Hi TI-experts,

 

for a long time, we had the problem, that we couldn't communicate with the Eval board. Now we change the BQ chip with one of the samples you supplied.

original chip on Eval board:

new sample on Eval board

We supply the Eval board with 10.8 V and it draws a current of 18.7 mA which seems to be fine. Here a picture of the connection:

On the output just a voltmeter is connected but we still measure 0V.

Here a screenshot of the BQ Studio

and the gg-file from the chip

Eval_Board_3S_0_02.gg.csv

What is missing that the charge and discharge FETs turn on? The [XCHG] and [XDSG] bits are cleared, so I thought the FETs should be on.

Kind regards

Tobias

  • +1
    TI__Mastermind 26115 points

    Hi Tobias,

    Here are the steps to getting the FETs to open.

    1 Configure the board jumpers for either the series or parallel FET path.

    2 send the FET_EN cmd so that FET_EN =1 

    3 Set disable all bits in the FET OPTIONS, RSVD bits can be left alone. data memory -> Settings -> FET options 

    4 Set NR=1, Data memory -> Settings -> DA config

    5 disable all protections

    6 send a reset cmd 

    Regards,

    Diego

  • 0 in reply to Diego
    Prodigy 80 points

    Hi Diego,

     

    Thank you for the quick answer, after Step:

     

    3 Set disable all bits in the FET OPTIONS, RSVD bits can be left alone. data memory -> Settings -> FET options 

    Before

    All Bits cleared - > Voltage present at Pack + / -

    SLEEPCHG & OTFET set -> Voltage still present at Pack +/-

    Can you give use more explanation about the bits [DFETOFFIN_EN] [CFETOFFIN_EN] [DDSGOUT_EN] [DCHGOUT_EN], in the TRM I only see the lower 8 bits in FET Options

     

    Regards,

    Tobias