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Low Voltage Clamp for Microcontroller

Discussion in 'Microcontrollers, Programming and IoT' started by Firebringer, Nov 7, 2011.

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  1. Firebringer

    Firebringer

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    Nov 7, 2011
    I'm currently playing with a microcontroller with sensor inputs that detect and report voltages. I'd like to hook these up to several different types of probes (temperature, light, current, etc).

    The uC, however, needs to be protected as a voltage in excess of 1.2v _might_ permanently damage it. I've read some articles that say a standard Zener clamp circuit is really designed for 5v or more. (see Voltage clamp circuits for ultra-low-voltage apps)

    The referenced article suggests using a MOSFET, but this seems to be for higher currents voltages (up to 1A) -- I don't need anywhere near this kind of current handling. Is there a reasonable middle ground circuit that provides adequate protection at 1.2v with the simplicity of a Zener clamp?? NOTE: This is all DC.

    thnx
    firebringer
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Two forward biased diodes should do the trick.
     
  3. Firebringer

    Firebringer

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    Nov 7, 2011
    Hmm. A standard diode wouldn't work here (too much forward voltage), but maybe a schottky??

    How stable do these tend to be?? How much tolerance expected in manufacturer's specs??

    For purposes of design, I'm treating the 1.2v as an _absolute_ ceiling.

    thnx
    firebringer
     
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