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CC2745R10-Q1: Average Current Consumption when Enabling CS ranging

Bob Li
Prodigy 70 points

Part Number: CC2745R10-Q1

Hi E2E,

Could you please share the average current consumption when performing capacitive sensing ranging with CC2745R10-Q1?

We'd like to evaluate whether it's feasible to enable CS ranging in a physical key fob without causing significant power drain. Ideally, ensuring the device won't run out of power within a few days.

Best,

Bob

  • 0
    TI__Genius 9995 points

    Hello Bob, 

    Is there a specific antenna configuration, connection interval or TX power you are looking for? Additionally, since you are looking for key fob use case in particular, I assume you would want to evaluate reflector/peripheral power consumption?

    Let me know and I can provide some numbers. 

    Thanks,

    Isaac 

  • 0 in reply to Isaac Larson
    Intellectual 280 points

    There are two antenas configuration.  Tx power is 10dbm.  Connection Inverval is 50ms.  The keyfob will work as reflector.  It will  better if  you can provide average current with different configuration that TI have tested. Thank you!

  • 0 in reply to chen jinwei
    TI__Genius 9995 points

    Hello Chen, 

    We have tested 2x2 antenna configuration, with 10 dBm, but the connection intervals we have tested are 15ms and 30ms. I will provide the reflector data for 30ms connection interval below. 

    Tx Power (dBm) Connection Interval (ms) Antenna Permutation Average Total Current (mA) Average Procedure Current (mA) Average Data Transfer Current (mA)
    10 30 2x2 7.5 16.68 13.86

    Below I have energy usage for the case above. 

    Tx Power (dBm) Connection Interval (ms) Antenna Permutation Average Total Reflector Electric Charge Used (nAh) Average Total Reflector Energy Used (mJ)
    10 30 2x2 450 5.35

    Additionally, I will add some explanation for each process we are measuring in the average current table. 

    The total current is equal to the entire waveform. See the note on the bottom of the image. The Procedure will be the first series of peaks, which is the phase based ranging procedure. The next series of peaks will be the data transfer. The data transfer will move the PCT data collected by the reflector back to the initiator for post processing. The energy measurement is from the Complete procedure. 

    Also, for a 50ms connection interval (compared to 30ms) the time taken to complete the procedure will be longer. This will reduce the overall energy and average current consumption for the entire procedure as there will be more time in between where nothing is being done. 

    Please let me know if you have any questions or would like to see any more data. 

    Thanks,
    Isaac

  • 0 in reply to Isaac Larson
    Intellectual 280 points

    Hi

       Thank you for you reply.  For 50 ms connection interval, Is it possible that the total average current can be reduce to below 5mA. If  We expect to make sure  the keyfob total average current below 5mA when perform  CS Ranging .  what we can do to meet this requirement.  Thank you for your support.

  • 0 in reply to chen jinwei
    TI__Genius 9995 points

    Hello Chen, 

    I wouldn't be surprised if the average current for 50ms connection interval is 5mA or lower. Because the connection interval is larger you will have more down time between the phase collection and the data transfer. This brings the total average current lower. 

    Note, with a higher connection interval, the time per CS procedure will be increased, which will reduce the amount of distance measurements obtained per second. 

    Thanks, 
    Isaac