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Best way to controll a Voltage regulator!

Discussion in 'General Electronics Discussion' started by crystal please, Dec 2, 2016.

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  1. crystal please

    crystal please

    10
    0
    Jul 5, 2016
    Hi,
    I want to control a voltage regulator (LT3080) using a PIC18F4523 running at 8MHZ.
    I would like to generate a control voltage, for the above regulator, that is reasonably accurate (2mV steps).
    I came up with two possible solutions and would like you to help me to decide which one is the best.

    Solution 1)
    Use a PWM signal + RC filter + voltage follower.
    If I choose this method what PWM frequency is most effective? And do I need a very precice Op Amp?

    Solution 2)
    Use a D.A.C. (like MCP4922) + voltage follower.
    If I choose this method what are the kind of issue I have to take care-of?

    I would really like to hear you opinion!

    Regards
    crystal
     
  2. Arouse1973

    Arouse1973 Adam

    5,165
    1,087
    Dec 18, 2013
    Solution 2 for me.
    Thanks
    Adam
     
  3. Harald Kapp

    Harald Kapp Moderator Moderator

    11,160
    2,548
    Nov 17, 2011
    What is the voltage range and/or application you want the regulator to use in?
    For certain applications there are specialized, digitally programmable regulators, see e.g. here.

    And here's a Microchip application using a DAC and an LM2670 linear regulator.
     
  4. Colin Mitchell

    Colin Mitchell

    1,417
    313
    Aug 31, 2014
    Use a PWM signal + RC filter + voltage follower transistor (emitter-follower).
    Use any frequency as the filter will will remove the fluctuations.
     
  5. AnalogKid

    AnalogKid

    2,466
    712
    Jun 10, 2015
    How quickly must the supply output respond to a step change, like going from 5 V to 12 V? This affects the PWM frequency and filter design.

    ak
     
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