PIC16F877A Buck Converter Design Help

[endofmk]

Hello,I want to design a buck converter circuit. It will have a 24-volt input and a 12-volt output. I have assembled the circuit and written the code, but when I provide 24 volts, I'm getting a 24-volt output. Can you please tell me where I went wrong?

https://imgur.com/6JAUu4P

 

[KlausST]

Hi,

did you measure V_GS?
I mean you have a simulation software, so use it to investigate what´s happening?

****
On the other hand:
Why do you try to re-invent the wheel? There are proven schematics all over the internet.
And semiconductor manufacturers provide very reliable application notes on how to do buck converter designs properly.

Klaus

 

[endofmk]

Hi,

did you measure V_GS?
I mean you have a simulation software, so use it to investigate what´s happening?

****
On the other hand:
Why do you try to re-invent the wheel? There are proven schematics all over the internet.
And semiconductor manufacturers provide very reliable application notes on how to do buck converter designs properly.

Klaus

Hello, this is my project and this is how it's requested to be done. I have no idea how to do it.

 

[betwixt]

And what is U2(VC)?

Please insert images directly into the forum instead of using third party web sites.

Brian.

 

[FvM]

I have assembled the circuit and written the code

No complete circuit. How are IR2112 and uC supplied, your simulation circuit doesn't tell.
IR2112 isn't suited as PMOS driver. A real transistor will be killed by -24V Vgs.

 

[KlausST]

Hello, this is my project and this is how it's requested to be done. I have no idea how to do it.

So I guess you did spend no time to measure V_GS.

What is this? A school project? Who requesed it to be done "this way"?
I can´t see how it can work.

Klaus

 

[BradtheRad]

Simulation showing what waveforms you can expect. Supply 24 VDC, output 12V 1A. The analog-switch is a simulated artificial switching component (mosfet). The switching component must turn fully On and shut fully Off, therefore it needs to be biased to turn it fully On & shut it fully Off. 5V is not sufficient to shut a P-device entirely Off when that P-device has 24V supply.

Also is there a ground for your U1?