Designing Open Loop Isolated Push-Pull Converter (Part 12/12)

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//Program to
////// Code for Closed Loop Boost converter with variable output voltage ////////
////// Output Voltage Adjustment from 5V to 9V ////////

#define TOP 1599                  // Fosc = Fclk/(N*(1+TOP)); Fclk = 16MHz, Fosc = 10kHz
#define CMP_VALUE_HALF_DUTY 799    // 50% duty cycle
#define FeedbackPin A4             // Input pin of potentiometer at A4
#define Inputpin A5                // feedback pin of potentiometer at A5
#define R1plusR2_resistor 6.0    // variable of R1+R2 value
#define R1_resistor 1.0             // variable of R1 value
#define PWM 9                     // PWM(Pulse Width Modulation) wave at pin 9

//// function declaration  
float Map_feedback(float);            //function to map feedback values
float Mapping_output_voltage(float); //function to map potentiometer values
void InitADC(void) ;                 // Function to start ADC conversion
uint16_t ReadADC(uint8_t);            // function to read Analog value

 ///// function definition   ////////
float Mapping_output_voltage(float Input_Read ){              
 
float Compare_voltage = (((Input_Read*(1.0)/1024)*4)+5);   // mapping the digital value
return(Compare_voltage);                               // return the calculated output voltage
}

void InitADC(void){                                            

ADMUX &= ~((1<<REFS1)|(1<<REFS0));           // for setting Aref = AVcc , internal Aref turns OFF
ADCSRA = (1<<ADEN)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);    //Prescalar div factor =128
}

uint16_t ReadADC(uint8_t channel_number)  {                       

//clear other than last three bits of the channel_number              
channel_number &= 0x07;
//clear last 3 bits of ADMUX, OR with channel_number
ADMUX =  (ADMUX & 0xf8) | channel_number;
//start ADC conversion
ADCSRA|=(1 << ADSC);                         
//wait for conversion to complete
while((ADCSRA) & (1<<ADSC));
//return ADC value
return(ADC);        
}

float Map_feedback(float Digital_Read){                           
 
float ADC_READ = (Digital_Read/1024.0)*3.33;            // converting digital values 
float output_voltage  = (ADC_READ*(R1plusR2_resistor/R1_resistor));  // calculating output voltage
return(output_voltage);                                // return the calculated output voltage
}
////////// function definition complete//////////

void setup() {
  // put your setup code here, to run once:
pinMode(PWM,OUTPUT);                               // set 9 pin as output
pinMode(FeedbackPin,INPUT);                       // set A4 pin as input
pinMode(Inputpin,INPUT);                            // set A5 pin as input
InitADC();                                          //start ADC conversion         
TCCR1A = 0;                                      //reset the register
TCCR1B = 0;                                     //reset the register
TCNT1 = 0;                                         //reset the register
TCCR1A |= (1<<COM1A1);                             // set output at non inverting mode
TCCR1A |= (1<<WGM11);                              // selecting Fast PWM mode
ICR1 = TOP;                                      // setting frequency to 10KHz
TCCR1B |= (1<< CS10)|(1<<WGM12)|(1<<WGM13);      //Timer Starts
OCR1A = CMP_VALUE_HALF_DUTY;                      // setting PWM of 50% duty cycle
delay(1000);                                     // delay for compensating 

void loop() {
  // put your main code here, to run repeatedly:
  float Digital_Read = ReadADC(0x04);                           // read feedback pin value
  float actual_output_voltage = Map_feedback(Digital_Read);     // map feedback value to desired volatge
  float Input_Read = ReadADC(0x05);                             //read potentiometer value
  float Compare_voltage_input = Mapping_output_voltage(Input_Read);   // map potentiometer value
 
  if(actual_output_voltage > Compare_voltage_input) //comparing actual output voltage
  {
    OCR1A --;                        // if error is positive the duty cycle is decreased  
  }
  else if(actual_output_voltage < Compare_voltage_input)
  {
  OCR1A ++;                       // if error is negative the duty cycle is increased
  }
}
 
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