# Boost converter design help

I need help on a 12v-220v Boost converter design. the converter is to have a feedback system that keeps the output voltage steady even when the input voltage drops. I have done a lot of reading and designs using a NE555 as the control system but it seems all my calculations are wrong. I am able to get a 250v output but if I add a load to it the output voltage drops drastically. I'm really confused. I need to use it for an inverter project in an exhibition next month. So please I need help.

I will attach the screen shot of the simulation on proteus 8.

• "...the output voltage drops drastically." Then your inductor is too small. – Ignacio Vazquez-Abrams Aug 19 '15 at 21:31
• I would also try placing a simple resistive load at the output, then measuring the voltage across that instead of plugging directly into a DMM. – RYS Aug 19 '15 at 21:51
• What is your frequency you are switching at? Are you sure the output of your 555 is a push/pull output or is it an open collector output? – KyranF Aug 19 '15 at 22:36
• I agree that you need a resistive load for a more accurate simulation result – KyranF Aug 19 '15 at 22:36
• @KyranF: NE555 is specified as push-pull, so I would be very surprised if it was OC. – Ignacio Vazquez-Abrams Aug 20 '15 at 0:09

Energy = $\dfrac{L.I^2}{2}$