Self powered PIC, app note. How to do.


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  1. #1
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    Default Self powered PIC, app note. How to do.

    I found this app note from Microchip which may be of use to someone for battery operation.

    Vdd Self Starting Circuit
    Building on the previous topic, the same charge
    pump can be used by the MCU to supply its
    own Vdd. Before the switch is pressed, Vbat
    has power and the Vdd points are connected
    together but unpowered. When the button is
    pressed, power is supplied to Vdd and the
    MCUs CLKOUT (in external RC oscillator mode)
    begins toggle. The voltage generated by the
    charge pump turns on the FET allowing Vdd
    to remain powered. To power down the MCU,
    execute a Sleep instruction. This allows the
    MCU to switch off its power source via software.
    Advantages:
    • PIC MCU leakage current nearly 0
    • Low cost (uses n-channel FET)
    • Reliable
    • No additional I/O pins required
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    Rob.

    The moment after you press "Post" is the moment you actually see the typso

  2. #2
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    Default Re: Self powered PIC, app note. How to do.

    Very interesting. Did you get the AN number?

    Robert

  3. #3
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    Default Re: Self powered PIC, app note. How to do.

    Hi Demon,

    It came from the Hints n Tips pdf in the other post here. Lots of good stuff in it.
    Rob.

    The moment after you press "Post" is the moment you actually see the typso

  4. #4
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    Default Re: Self powered PIC, app note. How to do.

    Indeed very interesting but could someone explain the circuit some more ?? i can't understand the "• PIC MCU leakage current nearly 0"
    Why is that happening ??
    One man's magic is ANOTHER man's engineering.
    Supernatural is a null word

  5. #5
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    Default Re: Self powered PIC, app note. How to do.

    Sorry for my hasty question. I studied the circuit some more and understood it. It's an electronic switch, indeeed very nice circuit !!
    One man's magic is ANOTHER man's engineering.
    Supernatural is a null word

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