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BQ25150: min max values of ADC conversion time?

Stefan Lintner
Expert 5115 points
Part Number: BQ25150

Hi Team,

customer is considering using timers instead of interrupts to fetch ADC data after manual mode conversion.
For this they would need the min/max values of the ADC conversion time. Could you provide them?

BR,
Stefan

  • 0
    TI__Mastermind 23410 points

    Hi Stefan,

    This will depend on the ADC_CONV_SPEED that is set. This is set in the ADCCTRL0 Register. The minimum is 3ms and the max is 24ms. Are they looking for the min max for each setting?

    Is there a particular reason they are using timers instead of interrupts?

    Best Regards,

    Anthony Pham

  • 0 in reply to Anthony P Pham
    TI__Expert 5115 points

    Hi Anthony,

    Thank you for the feedback, however customer is more interested in the min/max values of each delay.

    Some additional questions:

      • Are all  the ADC channels converted in parallel
      • Is there any consequence on enabling all channels together?
      • Is there any advantage to disable unused ADC channels?
      • what is the ADC power consumption per channel?
      • In charger mode(VIN present) how exactly does the ADC work?  When the ADC channel is enabled on demand sometime the data got corrupted (see below)
      • Are there more datasheets or application notes available?

    BR,
    Stefan

  • 0 in reply to Stefan Lintner
    TI__Mastermind 23410 points

    Hey Stefan,

    Let me look and check on this.

    Best Regards,

    Anthony Pham

  • +1 in reply to Anthony P Pham
    TI__Genius 17615 points

    Hi Stefan,

    To answer some of your questions:

    Stefan Lintner said:
    however customer is more interested in the min/max values of each delay.

    I have not found characterization data on these values, but I will continue to look for this information.

    Stefan Lintner said:
    Are all  the ADC channels converted in parallel

    No, they are converted serially.

    Stefan Lintner said:
    Is there any consequence on enabling all channels together?

    This should only increase the power consumption of your device.

    Stefan Lintner said:
    Is there any advantage to disable unused ADC channels?

    The charger will consume less power if unused ADC channels are disabled.

    Stefan Lintner said:
    In charger mode(VIN present) how exactly does the ADC work? 

    In this mode the ADC will convert with a 24 mS measuring period in continuous reading mode with all channels enabled. 

    Stefan Lintner said:
    When the ADC channel is enabled on demand sometime the data got corrupted (see below)

    Can you indicate the expected values for the provide scenario, which portion is the corrupted data? Is this with VIN present or in VBAT only mode and what is the selected conversion speed? Is there corruption when continuous mode or 1 second mode is selected? 

    Stefan Lintner said:
    Are there more datasheets or application notes available?

    There aren't any additional datasheets for the ADC included in this device, though we do have this app note available on utilizing the ADC to estimate state of charge: www.ti.com/.../sluaaa1

    Best Regards,

    Juan Ospina

  • 0 in reply to Stefan Lintner
    TI__Genius 17615 points

    Hi Stefan,

    Stefan Lintner said:
    what is the ADC power consumption per channel?

    In active battery mode, I found that, with 4.2V battery, enabling or disabling most of the ADC channels changed quiescent current consumption by approximately 1-2 uA, however enabling the TS Read increased current consumption by about 74 uA.

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    TI__Expert 5115 points

    Hi Juan,

    Regarding 

    When the ADC channel is enabled on demand sometime the data got corrupted (see below):

    VIN is present and they read the value at any time(as written in the DS page 20 8.3.3.2). They set the conversion speed to 24 ms. Normally they would measure around 480 mV voltage in the figure below. The kind of decay/drop effect is not expected in this measurement.

    s far as they can understand the maximum reading time is of 24 ms when all channels enabled. So it could be less when they enable a single channel?

    BR,
    Stefan

  • 0 in reply to Stefan Lintner
    TI__Genius 17615 points

    Hey Stefan,

    I don't believe that enabling a single channel affects the rate of the read time but I can attempt to recreate this on my side. To confirm the test settings VIN = 5V, VBAT = 3.6V, ADC is set to Manual Read, 24s, only ADCIN channel enabled, and 0.48V on ADCIN?

    Best Regards,

    Juan Ospina