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BQ34Z100-G1 RAC and masking alert

INg
Genius 3475 points
Other Parts Discussed in Thread: BQ34Z100-G1

Hi

My customer is using the BQ34Z100-G1, in the four LED format, led not always on (LED/COMM Configuration Bit 3 is clear)

We are using the datasheet SLUSBZ5 –JANUARY 2015

He would like to set-up the gauge to  automatically light up the LED when the capacity hits below 25%.

Therefore he needs to only set alert for lesser than maybe 25% of batt capacity .

I would like to check with you the following:

  • Is the RCA mentioned the datasheet, page 40/60 set by the SOC1 and SOCF (found on page 25)? Is this the right place to set the threshold for less than 25% capacity?
  • On table 22, there are a list of alerts that are Or-ed together. How do we mask off the alerts that are not needed?

Ivan

  • 0
    TI__Guru 73830 points
    Ivan,
    The RCA and EOD flags in the Alert register do correspond to the SOC1 adn SOCF flags in the Flags register. These flags provide a warning when the capacity reaches a certain threshold, but it may not occur at exactly 25% SOC. Note that you cannot use the I2C interface when using the 4-LED mode. If you only want to light one LED and you want to light it when the SOC drops to 25%, then you may want to use the ALERT output to control the LED. I am not sure that the P2 will be able to sink enough current to turn the LED on, so you may have to use a PFET in a high side configuration and use the P2 output to switch the gate of the FET. The LED may not light at exactly 25%, but you should be able to get close.

    The ALERT bits are OR'ed, so you would only enable the bit that you want to light the LED.

    Tom
  • 0 in reply to ThomasCosby
    Genius 3475 points

    Hi Tom

    Thanks for your confirmation on the relationship between RCA and SOCx registers.

    On page 40 of the data sheet. 
    All alerts description comes with a statement"

    "

    ALERT is enabled when set.

    "

    It appears that it is possible to mask a particular alert from being or-ed to the alert.

    Can you advise how to set the mask?

    Ivan 

  • 0 in reply to INg
    TI__Guru 73830 points
    The Alert register is implemented as a masking register. You set the bits to 1 for the flags that you want to flow through the ALERT output.