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CURRENT MODE PWM BUCK DCDC output ripple!

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lj053

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Can anyone tell me what the ripple looks like is a good design.
Its like a ^^^^^^ or ~~~~~~?
thanks.
 

IanP

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The ripple in output voltage appears to be sinusoidal (output smoothing capacitor).. see picture below ..

Regards,
IanP
 

lj053

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Hello IanP:
if you add the esr(200mohm) to the output cap.
Its output ripple just like ^^^^, not sinusoidal.
 

IanP

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Therefore I used the word "appears" not "is" ..
In a "good design" you don't have just single capacitor as the output LPF, but there will be another L-C stage ..

Rgards,
IanP
 

lj053

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Hello IanP:
In a "good design" you don't have just single capacitor as the output LPF, but there will be another L-C stage ..

You mean to add another L C filter at the output?
thanks.
 

hktk

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does IanP mean the pi filter used as LPF?
it is formed by a large capacitor, an inductor and another capacitor.
 

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