I am trying to design my own boost converter and so am learning about coils.
The switch of our boost converter has just opened, there was 100 mA flowing though the coil, now it has nowhere left to go, so the coil pushes all that energy into the capacitor, charging it up. I want to calculate the capacitor voltage after it’s been charged.
As you can see from my calculations, we should see the capacitor charged to 1 V, however that doesn’t happen. We are working with ideal components so the only route for energy to escape is in the diode. Its voltage drop is exactly 0.7 V.
My approach to calculating the energy lost by the diode looks like this:
We multiply the voltage drop of the diode by the average current that was flowing through it during the entire charge time, and then multiply that by the total charge time. - As you can see in the photo.
The issue is, I don’t know how to calculate both the charge time and the average current, I only know the minimum and maximum values. Also, the current flowing through the coil does not fall linearly, it’s ever so slightly slowing down as we approach zero.
How do I calculate these two values: The total charge time and the average charge current?
Thank you very much for all your help.
Component values, if needed:
- Coil: 1 mH
- Capacitor: 10 uF
- Diode Vdrop: 0.7 V
- Coil current: 100 mA