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Initial powerup and exit from shutdown

Andrew Newton
Prodigy 120 points
Other Parts Discussed in Thread: BQ20Z65

Hello, 

I have a bq20z65 device but I am struggling. I have done this accidentally in the past but I'm not sure where to find the information - I have seen it written once before and this is how I have managed accidentally but there are so many datasheets and notes relating to the gas gauges that I simply cannot find them again. 

I have got my board, it works on the whole - however I do not know how to get the texas device out of its shipping sleep mode. I recall that it involves shorting across two terminals but I'm just a little lost. Perhaps someone can let me know and ideally point me to the getting started guide which describes this (which is ironically not the getting started guide apparently!). It's an excellent device and I don't want to drop it from the design!

The guide I read even went into calibration of the device and was excellent. I just don't seem to be able to find it. 

Kindest thanks as always. The help on here is always prompt and accurate so I remain in your debt. 

  • 0
    TI__Guru* 76230 points

    Momentarily short 4P and Pack+ pins to wake-up the gas-gauge from shut-down mode.

    See apps notes SLUA409a (Calibration of bq20zXX Using EV Software ) and SLUA421a (quick start guide for bq20zxx family gas guages) for further help using the device.

    Onyx

  • 0 in reply to Onyx Ahiakwo
    Prodigy 120 points

    Thanks, the app note SLUA409a was the one I was thinking of. That's absolutely ideal. Thanks for your help. 

  • 0 in reply to Andrew Newton
    Prodigy 120 points

    I have been working through this device for a little while now and I have had power connected externally to my system, I have had a simulated battery (resistors and power supply) connected. 

    Despite following the instructions (and understanding the point of shorting the two points described in SLUA409a) I still fail to get the device to wake up. There is still no communication on the SM bus between the z65 and the EV2300. The EV2300 is working properly. I have tried it in all configurations with external power connected and disconnected, real batteries and simulated batteries. 

    Now, the reality is that *eventually* this device wakes up - but not reliably so. I am wondering if I'm just being a little simple and following the instructions to just the letter isn't helping me understand what's going on. For instance, this has just sprung into life and I haven't been near it shorting the input to the protected side of the supply. Why might this behavior be so erratic?  

    Best of thanks.