Calculation
Vo=10V
Vi=2.5V
For Boost Converter, the duty cycle of the pulse required is D=1-(Vi/Vo)=0.75
It is normal to operate coils at a frequency which is not perceived by the human ears. so let's keep the frequency at 20kHz . i.e the switch is operated at this frequency.
The above equation of duty cycle is valid only if the boost converter is operated in continuous mode. i.e Inductor current never falls to zero.
To make sure of that, the inductance of inductor should be greater than the inductance L
L=D*(1-D)*(1-D)*R/(2*f)
=0.75*0.25*0.25*100/(2*20000)
L=117uH. We have chosen a value of 200uH to make sure the below converter operates in continuous mode.
The output capacitor C required to limit the output ripple voltage to 1 percent is determined
C>=D/(R*0.01*f)=37.5uf. I have chosen a standard 47uf.
Note: The Duty cycle has been calculated assuming that voltage drop across the diode is 0V. But the diode used in the above circuit has practical voltage across it. So we have made duty cycle as 77 here to get the required output voltage.
The Simulation can be found out here -->http://tinyurl.com/qgao6jy
