int potentiometer = A0;
int feedback = A1;
int VIN = A2;
int PWM = 3;
int pwm = 0;
float V1=0;

void setup() {
  pinMode(potentiometer, INPUT);
  pinMode(feedback, INPUT);
  pinMode(VIN, INPUT);
  pinMode(PWM, OUTPUT);  
  TCCR2B = TCCR2B & B11111000 | B00000001;    // pin 3 and 11 PWM frequency of 31372.55 Hz
}
 

void loop() {
  float Vp = analogRead(potentiometer);
  float output1  = analogRead(feedback);
  float Vin1  = analogRead(VIN);
  
  float output = ((5.1+20)*output1)/5.1;
  float Vin = ((5.1+20)*Vin1)/5.1;
  float D = ( Vp/1023);
  float Vout = Vin * (1-D);

  while (output != Vout)
  {

    
  if (Vout > output)
   {
    Vp = Vp-1;
   
   }

  if (Vout < output)
   {
    Vp = Vp+1;
     
   }
   int Vpo= map(Vp,0,1024,0,225);
   analogWrite(PWM,Vpo);
   
   float output1  = analogRead(feedback);
   float output = ((5.1+20)*output1)/5.1;  
}
}