Buck,Boost,Inverting Converters

Thread Starter


Joined Mar 22, 2009
I've attempted this but I'm not sure if I have the right answers or not, questions are as follows:

For all three circuits,

My answers were as follows:
1) Vin = 0.533V
2) Vin = -130V
3) Vin = 7.677V

thanks for your help!
Last edited:


Joined Mar 6, 2009
Without actual circuit values other than Vout=7V and duty cycle=21%, it's hard to give a answer ..

Since first circuit is a buck type I would expect Vi to be greater than Vout - 0.333 volts seems wrong - maybe you meant 33.3V

Second is a boost type - at 21% duty cycle expect Vin to be only slightly less than Vout - say around 6V. I doubt -140V is correct.

Not sure about the third - you could try a simulation and watch what happens with parameter changes. It's obviously negative output with positive input - buck behaviour? Say Vin=30V ????

No simulator?



http://www.simetrix.co.uk/ - limited no. of nodes in freeware schematic