I wanted to dive in Power Electronics and create a 24V DC-DC Boost Converter that would run from 2.5 to 5 V power supply. 80% efficiency was assumed, and 30 kHz frequency chosen for the PWM.
Initial Parameters
Duty Cycle
Assuming the forward voltage drop of a diode was 0.5, duty cycle was calculated in the following manner.
Inductor & Capacitor
I only had 220μH inductor & 100μF capacitor around, so those two have been chosen for the circuit.
Circuit
Here is the DC-DC Boost Converter circuit with the inrush current protection.
PWM signal is generated by PIC10F200, and PWR is 2.5 - 5 volts.
Problem
I have made the circuit on a perfboard, and it is working perfectly. However, the output voltage is much higher than expected, around 75 volts, and has fried my regulator as I have omitted the Zener regulation.
Were my calculations wrong, should the PWM be tweaked?