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BQ76952: BQ76952 Power Consumption

Federico Casali
Prodigy 75 points
Part Number: BQ76952


Hello,

I am working with the BQ76952 IC and have some questions regarding its power consumption. In the Technical Reference Manual, there are some values listed for different operating modes:

Multiple power modes (typical battery pack operating range conditions) 
– NORMAL mode: 286 µA
– Multiple SLEEP mode options: 24 µA to 41 µA
– Multiple DEEPSLEEP mode options: 9.2 µA to 10.7 µA
– SHUTDOWN Mode: 1 µA 

However, when I measure the current drawn using a shunt resistor in the BAT pin, I consistently see higher consumption than the datasheet suggests:
– NORMAL mode: 725 µA
– SLEEP mode: 403 µA 
– DEEPSLEEP mode: 357 µA 
– SHUTDOWN Mode: 1 µA 

I would like to clarify a few points:

  1. Are the power consumption figures in the manual typical or idealized values, and under what exact conditions are they measured?

  2. When measuring with a shunt resistor in my system, is it reasonable to expect higher readings due to additional circuit factors (e.g., external load, interface circuitry, or measurement method)?

  3. Are there common factors that typically increase the BQ76952’s current consumption beyond the datasheet values?

Any guidance on understanding the reference numbers versus real-world measurements would be very helpful.

Thanks in advance,

Federico

 

  • 0
    TI__Expert 5270 points

    Hi Federico, I am suspecting from your numbers that this may be related to the customer LDO(s) in the device.  Can you double-check the supply current with the REG0, REG1, and REG2 all disabled in the settings, to see if that affects your readings?

    Thanks,

    Terry

  • 0 in reply to -Terry
    Prodigy 75 points

    Hello Terry.

    The supply current is still around 350 µA with those LDOs disabled. I do have some NTCs connected to REG18 but they don't account for all the supply current I am measuring. May I share with you privately the schematic?

    Thanks,

    Federico

  • +1 in reply to Federico Casali
    TI__Expert 5270 points

    Hi Federico,

    Yes, you can share the schematic privately.  Per your question about the supply current, the numbers are typical, so the average measured across many parts.  They should not vary so greatly as what you are describing without some other explanation.

    We can probably start debug by focusing on DEEPSLEEP mode, since that has all measurements and protections disabled.  The only items still powered are typically the REG18 LDO, maybe or maybe not the LFO oscillator, and then maybe or maybe not the REG1/2 LDOs, based on your settings.  You can disable REG0, REG1, and REG2, so those blocks are off, and any load that might be connected to those nodes would no longer be driven.

    You might also review anything connected to the multifunction pins, since those can be configured for GPO or Alarm functionality and drive a high signal output, with that current potentially coming from the BAT pin current.

    Thanks,

    Terry

  • 0 in reply to -Terry
    Prodigy 75 points

    Hello Terry,

    After reviewing the schematic with you, the increased power consumption comes from some NTCs connected to REG18. Now the values I read are consistent with those reported in the datasheet.

    Thanks for the support.