DC-DC Converter

[German1981]

Hello,
I am trying to build a DC-DC converter that actually follows a linear path. When the input voltage is 6 Volts, the output should be 20 Volts and when I crank the input voltage to 10 Volts, I would like the output voltage to be 125 Volts.
I built a boost converter that worked for the 6v to 20 volt conversion. Then I thought I could just increase the duty ratio as I increased the voltage using a microcontroller. But even with a max duty ratio, I cannot get this to work.
My question is this: Is it even possible to accomplish what I am trying to do? I am building this for a class project. Thanks.

 

[Nigel Goodwin]

Hello,
I am trying to build a DC-DC converter that actually follows a linear path. When the input voltage is 6 Volts, the output should be 20 Volts and when I crank the input voltage to 10 Volts, I would like the output voltage to be 125 Volts.
I built a boost converter that worked for the 6v to 20 volt conversion. Then I thought I could just increase the duty ratio as I increased the voltage using a microcontroller. But even with a max duty ratio, I cannot get this to work.
My question is this: Is it even possible to accomplish what I am trying to do? I am building this for a class project. Thanks.

I would have thought a linear path would give 33.3V, where did you get 125V from?.

What are you actually trying to do?.

 

[German1981]

No,
It would be linear, just not thru the origin. Picture a line, with endpoints (6,20) and (10,125). These two points produce a line; the line that I need my input/output voltage to represent.
So when I have 6 volt input, my out put is 20 volts. When my input is 10 volts, my output is 125 volts. The line equation is y = 26.25x -178.5. (y=output, x=input) . Thanks

 

[Styx]

what topology did you use for the boost circuit?

The only major problem I can see is with regulation.