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TMP117: average mode current consumption calculate method

Kai Lai
Expert 8986 points
Part Number: TMP117

Hi Team,

My customer is going to use our TMP117 in their peoject.

They have below questions need your kindly comment.

  1. For below averages sampling, we should understood that the temperature will be detected one time every second, and 8 times will be sampled for averaging in one data? and the sampling time for each time is 15.5ms?
  2. Is below consumption current in red box what I highlight is workable for Question 1's sampling method ?
    At this time, the I2C should transmit data to the MCU. The I2C bus should be active, right?
    Can you provide 8 average mode on + serial bus active power consumption for customer ?
  3. If we set to detect the temperature one time per every minute, 8 average mode on, can the current consumption be calculated as follows ?  If it is not correct, can you guide how to calculate it ?
    [(15.5ms x 8 x 135uA)+(59.876sec x 1.25uA)] / 60sec= 1.526uA

Thanks!

Kai

  • 0
    TI__Genius 10080 points

    Hi Kai,

    Thank you for posting to the Sensing forum.

    1. That is correct. Since 1 active conversion requires 15.5 ms, 8 averaged conversions will require 124 ms. The conversion cycle time is 1 second by default.
    2. The TMP117 has a typical specification of 135 µA for each active conversion (15.5 ms). If averaging is enabled the current consumption will increase to account for 124 ms of conversions.

    For 8 averaged conversions the average current can be estimated below:

    IAVG = (135 µA x 124 ms + 1.25 µA x (1000 ms – 124 ms)) / 1000 ms = 17.835 µA (estimate)

    • Where 1.25 µA is the standby current in continuous conversion mode.

    Best regards,
    Nicole