Digital Potentiometer and Power Supply

Discussion in 'Digital Circuit Design' started by Carlos Moreno, Jul 4, 2016.

  1. Carlos Moreno

    Thread Starter New Member

    Jul 4, 2016
    1
    0
    I have a DC-DC booster that is controlled with a 25 turn trimpot trimmer 100K potentiometer. I was wondering if I could use the MCP41100 as a potentiometer for the DC booster instead of the trimpot potentiometer.

    I tried using the digital potentiometer for the DC-DC booster and it worked, but the booster does not go as high as with the trimpot potentiometer. Would you know why is this so? Would you have a solution and a component I could buy? I am controlling the digital potentiometer with an Arduino with the following code:

    #include <SPI.h>
    byte address = 0x11;
    int CS= 10;
    int i=0;
    void setup()
    {
    pinMode (CS, OUTPUT);
    Serial.begin(9600);
    SPI.begin();
    }

    void loop()
    {

    if (Serial.available()>0)
    {
    int x = Serial.parseInt();
    digitalPotWrite(x);
    Serial.println(x);}
    }

    int digitalPotWrite(int value)
    {
    digitalWrite(CS, LOW);
    SPI.transfer(address);
    SPI.transfer(value);
    digitalWrite(CS, HIGH);
    }
     
  2. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,934
    383
    The track resistance for this pot may be anywhere between 70k and 130k so maybe the one you have is at the lower end of that tolerance range. You may be able to change a resistor in the booster to allow for the pot tolerance.
     
  3. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,797
    1,103
    Any voltage applied to the digipot must be within its rated limits or the pot will be damaged.
     
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