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embedding ERICSSON T10s board

Discussion in 'Electronic Design' started by PYCTAM, Jun 4, 2005.

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    PYCTAM Guest


    I want to use a ERICSSON T10s board (from disassambled phone with LCD)
    in one of my projects. How can I powering up the board? I couldn't do
    it by powering up through connector on the board without its battery.

    Rustam Bogubaev
  2. Steve Sousa

    Steve Sousa Guest

    You won't be able to use the phone without a battery, the power supply can't
    handle the current.
  3. Mac

    Mac Guest

    Are you saying that the phone relies on the series resistance of the
    battery for current limiting? If so, could he fake it with a series
    resistor? Or is it hopeless?

    Just wondering.

  4. Ian Stirling

    Ian Stirling Guest

    The power supply has sufficient average current to charge the battery
    with the phone operating.
    It does not (generally) have enough power to supply pulses of power needed
    when transmitting.
    Dismantling a battery (carefully) and replacing the lithium cell with
    a large capacitor (10mF?) may work.
  5. Guest

    A battery will eventually wear out. Proberbly much earlier than a capacitor.
    And in a stationary setup size won't matter that much. Any ideas on suitable
    sized capacitor ?
  6. Steve Sousa

    Steve Sousa Guest

    It depends a lot on your power supply and the lenght of you leads. You
    should place the capacitors as close to the phone as you can, and measure
    the voltage drop *at the battery terminals on the phone* using an
    osciloscope, try a couple of 1000uF 6.3V caps from an old motherboard, or at
    least 3 to 5 330~470 tantalums.

    For my tests i made a circuit with a 555 and a mosfet to replicate the
    circuit on the pdf i pointed you to. I couln't meet the less than 200mV spec
    only with capacitors without them getting hot, but neither did son*-**iccson
    themselves on the gt47 modem they sell. I posted a pic at abse of the signal
    on their modem, if you can get something similar or better you should be ok.

    Best Regards
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