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Battery operated WiFi

Isaac Zuker
Prodigy 40 points

Hi everyone,

I have an application in which the WiFi is battery-operated, hence need the lowest possible average current consumption.

It has to transmit every 10mSec. a 1Kbyte packet, and also receive every 10mSec. a 1Kbyte packet along a distance of 30 feet (10 meters), no walls in the middle.

Which device could give the lowest average current consumption, and what would be (approximately) the average current consumption?

Also need Bluetooth, so a combo would be a great solution (although not a must), provided it's energy efficient.

Thanks!!!

  • 0
    TI__Mastermind 22935 points

    Hi Isaac,

    Given the short periodic nature of your system it seems like you would have to stay connected to the network at all times. Because of this you will have to use our CC3220 in idle connected mode which is about 700uA.

    Then you also have to ask yourself how long does it take to send a 1kB packet? According to our datasheet a TCP packet can run at about 13Mbps (there's different rates for UDP). Assuming you can get that performance in your environment you're looking at about 0.6ms of transmission time every 10ms. Also, TX current consumption depends on the TX power level you require and the modulation scheme being used which can range anywhere from 157mA to 272mA.

    Finally we have yet to consider the size of the RX packet (which greatly influences the time) as well as the current consumption which is usually around 55mA during the duration of reception.

    We also have WiLink products that support both WiFi and BT on one part.

    I recommend you review our datasheet for the CC3220: www.ti.com/.../cc3220s.pdf
    Also check out our WiLink products so you can evaluate a potential WiFi + BT solution: 

    http://www.ti.com/wireless-connectivity/simplelink-solutions/wi-fi/overview/wilink-combo-solutions.html

    Jesu

  • 0 in reply to Jesu
    Prodigy 40 points

    Hi Jesu,


    Many thanks for your reply, I will check out the CC3220 datasheet.

    So, I understand that I should expect a worst-case current consumption of approximately 272*(0.6/10)+0.7+55*(0.6/10) = 20.32mA, is that right?

    Another question: should I expect interference issues if about 10 to 30 devices will be operating in the room?

    Best regards,

    Isaac

  • 0 in reply to Isaac Zuker
    TI__Mastermind 22935 points

    Hi Isaac,

    Not quite, you need to account for the duration of the idle connect stage which is a small adjustment.

    272*(0.6/10) + 0.7*((10-0.6-0.6) / 10) + 55*(0.6/10) = 20.24mA average for 10ms.

    I would still not consider this worst case because this does not account for any additional processing you're doing. 

    The device should be able to operate in that environment.

    Jesu

  • 0 in reply to Jesu
    Prodigy 40 points
    Many thanks Jesu!