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bq40z60 Removable Pack Sleep

Joe Stark
Prodigy 180 points
Other Parts Discussed in Thread: BQ40Z60

I have a bq40z60 configured as a removeable pack (NR=0) with sleep mode enabled (SLEEP=1 and IN_SYSTEM_SLEEP=1).  When the device enters sleep mode, every [Power:Voltage Time, Current Time=5sec] 5seconds, when the device turns back on to measure voltages and currents, it turns the DSG and CHG FETs on.  Is there a setting I am missing that keeps the FETs off throughout sleep mode?

Thank you all.

Joe Stark

  • 0
    TI__Guru 73830 points
    Joe,
    The gauge does not turn the DSG FET off on Sleep mode. I am not sure why the DSG FET Is off in your case. I did check on the bench and the gauge does not turn the DSG FET back on when it checks current and voltages, if I have it turned off. If you export an srec file, then I can test your specific configuration.
    Tom
  • 0 in reply to ThomasCosby
    Prodigy 180 points

    Thank you for your swift response, Tom.  Attached is the .srec file.  I believe part of my issue stemmed from the bq40z60 entering Shutdown mode instead of Sleep mode.  I also had an electrical circuit attached to the /SYS_PRES pin containing a pull-up resistor to a 2.8V logic supply and a button that pulled the /SYS_PRES line to GND when pressed.  When the device entered shutdown mode, the pull-"up" resistor to 2.8V was in fact pulling the /SYS_PRES pin down to GND enough such that the voltage was less than 1.3V. (The 2.8V supply powered a small processor downstream of the protection FETs).  

    The state-machine oscillation was stopped by removing the 2.8V pull-"up" resistor.  But any others suggestions for improved bq behavior would be much appreciated, Tom.  Thank you much.

    bq40z60_v0_13_build_19 - 4S1P NCR18650BL - sleep_test.srec.123

  • 0 in reply to ThomasCosby
    Prodigy 180 points
    Tom: In reading more about Sleep mode, it appears there are at least two variants: sleep mode as requested by a 0x0011 MAC command and the "regular" sleep command. The former is described in the Technical Manual in section 11.1.11; the latter in section 5.3.1. The former turns off all FETs, the latter says it only turns off the PCHG and CHG FETs. Is this behavior accurate with your experience?
    Thank you, Tom.