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BQ76942: Deep sleep mode enter condition

Fabio Gou
Expert 4575 points

Part Number: BQ76942
Other Parts Discussed in Thread: BQSTUDIO, EV2400

The customer encountered abnormal deep sleep entering issues.

I want to double confirm the deepsleep entering condition.

1. 

2. 

But the customer do not send the subcommand and also disabled the PF_DPSLP bit.

They also find that the BQ76942 entered deep sleep mode in their product line when doing the charge and discharge cycle.

Is there any other condition could lead to this? Or any other reasons?

  • 0
    TI__Expert 4085 points

    Dear Fabio,

    1. Could you try disabling all the different permanent failures protections in the device settings in Protection Configuration to see if this still occurs?

    2. How are you confirming that the device is in DEEPSLEEP? What sort of current is the device pulling?

    Best,

    Asher Nederveld

  • 0 in reply to Asher Nederveld
    TI__Expert 4575 points

    I have connected EV2400 and BQstudio with their system and read the status. Besides, there is no LDO output(They closed it in deepsleep). There is no ADC sampling signal. So I guess it is in deepsleep mode.

    1.Except I mentioned the two conditions, is there other entering situation?

    2.I also encountered an I2CCRC error. But this do not affect the commands. I just can not read the data memory from the chip. Could you pls tell me what is the reason for the CRC error?

     

  • 0 in reply to Fabio Gou
    TI__Expert 4575 points

    This is the bit registers results reading the NG pack.

    Is there any other reasons could cause this deep sleep entering?

  • 0 in reply to Fabio Gou
    TI__Expert 4085 points

    Dear Fabio,

    Those are the only two ways the device enters Deepsleep that I have seen.

    1. Did you try disabling permanent fails to see if this same issue still occurs?

    2. Could you send me the schematic for the board?

    3. Does your device come with CRC enabled by default (i.e. what is the full device number? Bq7694202?)

    Best,

    Asher Nederveld

  • 0 in reply to Asher Nederveld
    TI__Expert 4575 points

    This deep sleep only appeared on the production line when doing the charging and discharging cycle.(Nearly everyone)

    They can not reproduce this in their lab even if enable the permanent fails.   

    Besides, they have disabled the PF_DPSLP bit. So the PF will not let BQ76942 enter deep sleep.

    Have you ever encountered the similar issue?

    3. Does your device come with CRC enabled by default (i.e. what is the full device number? Bq7694202?)

    I will double confirm this tomorrow. So if CRC enabled by default, this error will appear? After upgrade the software in EV2400, this error could be solved.

    5S1P-AFE-0619(1).pdf

  • 0 in reply to Fabio Gou
    TI__Expert 4085 points

    Dear Fabio,

    Are the readings you sent in the screenshots from the lab units or the production line? Is there any chance the programming process is different between the two? This hasn't been seen before and it seems like the most plausible reason is that the PF_DPSLP bit isn't actually being set low, and the charging cycle causes a large transient which triggers a PF. The other option is that the communication isn't functioning properly and so the data you are reading isn't 100% accurate (as seen in the BQStudio CRC error). Could you also disable auto-refresh and try reading the value of the DEEPSLEEP and PF_DPSLP bit multiple times via the Command Sequence feature to see if the values fluctuate at all?

    Best,
    Asher Nederveld