buck converter output voltage ripple

[mshh]

the ripple in output voltage of buck converter is high , the ripple is 1.5 v. switching frequency is 50khz,L=460uh,C=470uf

 

[barry]

That's a statement, not a question.

 

[dick_freebird]

That 470uF had best not be a lonely high-ESL
electrolytic....

 

[mshh]

what is the cause of high ripple ?how to reduce it?

 

[barry]

What is your load supply? Is there ripple on that? What is your output voltage?

 

[mshh]

I tried the power supply of the PC and i also tried the power supply in picture. i tried output voltage 6v from the PC power supply and 12 from the variable power supply. the output voltage had around 1.5v ripple

 

[KlausST]

Hi,

Yes...what are your test conditions?

What is the ripple frequency? Show a scope picture.
Did you carefully design the PCB according recommendations?

Klaus

 

[barry]

sending a picture of your power supply is almost useless. That’s like sending a Picture of your car to your mechanic and asking him to fix it. Except, I can see your supply is current limiting. See that little red light under ”cc”? That might be your problem.

and you still haven’t said what your output voltage is.

 

[tyassin]

Hi

I was wondering if these connection make sense. Especially the bootstrap capacitor. The only way it can charge is through the inductor and load.

 

[zenerbjt]

Your schem of top post is potentially very bad...you have no fast fet current sense.

Under certain conditions you can sometimes mitigate this in software, but i am not sure you have.

Generally, no fast fet current sense is bad...even in voltage mode, an overcurrent fet sense is necessary