Variable output buck converter

[mshh]

Hi
I want to design a buck converter using ICL7667 as MOSFET driver and output current of 1A. The input voltage should be 24 volts and the output should vary from zero to 24. I really do not know how to to do it. My Prof told me to find the capacitor and inductor of the circuit in order to always perform in CCM. With variable output I don't know how to do it. I calculated the inductor value for different duty cycles and the maximum one was 400 uH for when D=50%. And for capacitor I don't know what ESR is. I've searched a lot and all I got is for variable output I need a feedback, but my prof didn't say a thing about it. The only thing he said that might be helpful is that I should place the MOSFET in the bottom of the circuit instead of the top!
Sorry for my English!
Thanks in advance

 

[chemelec]

ESR is Effective Series Resistance.

But I don't know how you would create a "Buck Converter" with that ICL7667.
It is a "Dual Mosfet Driver" and rated for 15 Volts.

 

[chemelec]

I did a Google search for: "ICL7667 Buck Converter" and came up with a PDF File that Might be Useful for you.

But I was NOT able to copy a working Link for it into here.
(srttu-jecei-v1n2p73-en.pdf) Link Doesn't work.

Try this Seach yourself!

 

[ChrisP58]

Why do you want to use the ICL7667? While it is probably great when it is the right part for a particular job, in my opinion, it is NOT the right part for a 0-24V buck converter.

Your prof is correct in saying that you can use it if you put he mosfet in the ground leg, but that will add unnecessary complexity to the rest of the design. Starting with the fact that the output voltage will not be at the same ground potential as the input. And, while that may not be important in some applications, it will make the voltage feedback loop more complicated.

 

[mshh]

Why do you want to use the ICL7667? While it is probably great when it is the right part for a particular job, in my opinion, it is NOT the right part for a 0-24V buck converter.

Your prof is correct in saying that you can use it if you put he mosfet in the ground leg, but that will add unnecessary complexity to the rest of the design. Starting with the fact that the output voltage will not be at the same ground potential as the input. And, while that may not be important in some applications, it will make the voltage feedback loop more complicated.

Basically what a feedback in variable output buck should be contained of?

 

[chemelec]

Check out a LT1074.

 

[mshh]

Check out a LT1074.

My project is to design a classic buck circuit using a diode, mosfet, inductor and resistor.

 

[4pyros]

Maybe this should be in homework help.

 

[4pyros]

My project is to design a classic buck circuit using a diode, mosfet, inductor and resistor.

What happened to the ICL7667 MOSFET driver chip?