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  1. #1
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    Nokia 12 - Power Consumption

    >> Test on the Evaluation Card >>

    Hi everyone!

    I have measured the power consumption of Nokia 12 when it is on its Test Card.

    The standby average seems to be quite high.. ~ 150mA.
    It remains approximately the same when ' Blinker ' from the ExampleIMlets turns.

    When I try an Imlet with Mail operations (by GPRS), the power consumption is about 240-260 mA.

    >> My questions are : >>

    1- Is the high consumption on stand-by due to the Test Card ?

    2- I am thinking about making a specific card to my application, it won't use the Audio functions. What results can I expect concerning power consumption ? Would it be smaller ?

    3- I am looking for the same results that are in the technical specifications of Nokia 12. These are : 20mA in Stand By. How can I have them?

    Best Regards,
    Kzalei

  2. #2
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    A precision..

    What I have called ' Test Card ' is the ' Nokia 12 Test Board '.

    Xcuse me for my english..

  3. #3
    Regular Contributor
    Join Date
    Nov 2003
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    20 mA will be only, if no IMLet is running .
    Max expected current (average, not pulse!!!) is 350 mA in very bad coverage area.
    On test board are filtering tantalum capacitors - 2500uF in total, your power supply must have similar, else pulse current can rise up to 2A.
    When GPRS is online, power consumption rises, of course.
    All of this power goes to RF transmitter, when active, and ARM core, so average consumption in general is independent from application (take in account, that you must not load any output with current greater than 1mA ... - in fact, this value can be greater, but you must see N12 internal schematics in this case and calculate, what is possible, what not, because of I/O level translation system).

  4. #4
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    Thanks for your answer raimonds,

    As you may have several applications turning on it, maybe you should give some precisions about N12 consumption :

    >> What is the approximate autonomy that can be expected with the N12 ? (with a typical application ej. : sensor monitoring and daily connection to GPRS network)

    >> In the same area, which results do you obtain when Imlets are only turning for local purpose ?

    A secondary point.. do you know which processor is the ARM core of N12 (I believe it is ARM9xx?)

    Kindest Regards

  5. #5
    Regular Contributor
    Join Date
    Nov 2003
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    156
    Hi!
    N12 internals are the same as other NOKIA DCT4 based phones have, excepting firmware, of course (no UI part, extended data transfer functions, M2M protocol e.t.c).

    So, power consumption scenarios are very like standard phone, excluding audio, ringer, LCD and backlight power.
    When there are no IMLets running and no communications are active, N12 goes into sleep mode - ~20..50 mA at max.
    IMLet only - 100..150 mA (with some pulses at replies to base station query).
    Transmit mode - 350 mA max average, up to 2A pulse (see about this in HW guide).
    BUT.. if there is bad coverage or no coverage at all, power consumption will be large, because of max RF power level.
    N12 is communicating w base station even without active channels (as normal phone does).
    So good antenna is helpful in power reduction.

    Some undocumented things: N12 can work directly from standard phone accu, altough doesn't have realised charging path, in simple scenario is possible to use so called trickle charging mode. This is tested in real apps.

  6. #6
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    Thank you very much for all these details.

    So Ok, the essential point to low consumption will be to launch the IMlet only when it is needed.

    The problem is that my application is expected to work with a great autonomy. That means without frequent external intervention. So, all the control is assign to the IMlet.

    Is there a possibility for the Nokia 12 to fall in sleep mode and to launch an application at a given time.

    OR Is there a execution mode that will allow to reduce the processor activity when the IMlet has nothing to do but wait ?

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