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BQ40Z50-R1: Faulty current information from BQ40Z50

Part Number: BQ40Z50-R1
Other Parts Discussed in Thread: BQ24610, BQ40Z50, EV2400, LM25116, LM34936

Hi guys,

I made a drawing of the strange case we get on a BQ40Z50R1 + BQ24610 design.

We have 2 version of MotherBoard using 2 types of power architecture to generate 3v3, 12v and 5v

One of them (our new motherboard design) have a strange behaviour when reading data from BQ40Z50R1.

Charging and discharging the battery works well, system is correctly powered from battery but the data read from BQ40Z50 are not relevant

Using EV2400,

Current displayed = 0 when battery is discharging (remenber: battery powered correctly the system)

Current displayed = 20mA when battery is charging. (remenber battery is correctly charged after 2 hours)

and others parameters are also not relevant : 

For example : 'time to full' is very long (because current charge is 20mA)    But in real , current charge is 1.6A 

I can provide schematics of the 3 systems

Any idea to help ?

Regards

Gilles

  • How many units with this issue have you seen? Does it happen to only one unit?

     

    Andy

  • Hi Andy,

    We have manufacture a set of 100 Battery pack + BMS.   and 100 MotherBoards

    All of them have the same problem. 

    Gilles

  • In the association od BQ24610 and BQ40Z50, it seems that B24610 works correctly

    BQ40Z50 don't 'see' correctly the current deliver by BQ24610

    In term os system.

    We have old system where "BMS + Battery" works correctly when connect to 3 x MP4470 step-down

    Our new system where "BMS + Battery" does not work correctly when connect to 2 x LM25116 and 1 x LM34936

    By 'Not Working Correctly" , i mean information read from BQ40Z50 are not the value seen into the system

    If you compare solution based on MP chip and TI chip, that type of phenomena can produce this ?  self, resistance, impedance, LC, RC, other ?

    Gilles

  • Hi Gilles,

    If my understanding is correct,  the same "BMS + Battery" works well with System #1 and System #2.  Your problem occurs when System #3 that uses different buck and buck-boost controllers is connected.  Correct?

    I'm not the expert on the buck or buck-boost controller. I suggest you may want to check with the TI expert on these devices since the issue is related to the System #3 board.

    Andy