Please help, why chopper circuit is not working?

[radhika]

Respected,
I am Electronics student as current working on boost chopper circuit. I want to convert 3.7V to 19.5V using PWM of Arduino as shown in the attached link.

According to requirements, Vin = 3.7V Vout = 19.5V, D = 81.02%, R = 50 Ohm, I = 2.5A, F = 100kHz.
According to the formula, Lmin = (D((1-D)^2)R)/(2F) = 7.3uH
                                     Cin    = (I*D* (1-D)*1000)/(F*75m) = 50mF
                                     Cout  = (D)/(R*Vout*F) = 8.30nF
Using this formula I got required values, but still I  am getting incorrect voltage. Is formula's are wrong or the circuit connection or the code. Where do I need to do improvement? Please guide.
The Code i used for developing 81.02% duty cycle is :
int ledPin = 9;

void setup()
{
  pinMode (ledPin, OUTPUT);
}

void loop()
{
  analogWrite(ledPin, 206);
}



https://postimg.cc/image/f4kkolo0n/
https://postimg.cc/image/gm6100853/

[Wimberleytech]

The arduino default pwm frequency for that pin is about 500Hz.  Your design requires 100kHz.  In order to get a higher PWM frequency, you will need to put a little more effort into the code.  Here is an article that might help:
https://www.eprojectszone.com/how-to-modify-the-pwm-frequency-on-the-arduino-part1/

[radhika]

Okay, I will get code done right.
But, what about the circuit components. Are they all of correct values?

[Wimberleytech]

Okay, I will get code done right.
But, what about the circuit components. Are they all of correct values?

Your specifications seems odd: 2.5A into a 50 ohm load?  That does not comport with your desired output voltage.
Your output capacitor is way too low.

[radhika]

Hello,
As per the link given by you and I have tried building code.
Here is the code,


void setup()
{
 
 
  pinMode (5, OUTPUT);
  pinMode(6, OUTPUT);
  TCCR0A = 0;
  TCCR0B = 0;
  TCCR0A = 0b01010011;
  TCCR0B = 0b00001010;
  OCR0A = 9; //Control value of 100kHz, N = 8
}

void loop()
{
  analogWrite(5, 206)// 81% duty cycle;
}

I am using Proteus for checking output. As shown in the attached picture I an unable to get output at pin 6. Guide me for the circuit if I have attached to the wrong pin and the code.
PS: Apologies for the late reply.
https://postimg.cc/image/g84qnrsrr/