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Thanks , Taofeng !
But ...but ....
I must say ....
If you are right ------ the output pole is the dominant pole ,for example,
Po = -100HZ .
For the second dominant pole , the Miller pole , let's say , Pm = -1000HZ.
At the frequency Pm, the output cap ,as you say , is too pig , So...
Hi ,everyone :
I have one question :
The upload shcematic is a LDO . It uses the Miller compensation
as the upload paper using current buffer(T1 and C4) ?
In the shcematic uploaded , all cap is several pF , except the Cl ,which is
at least 2uF ( the datasheet specify " For stability...
Hi,everyone :
This is a LDO circuit .
R1,C2 generate a pole and a zero : p=-1/(R2+2Roc)C1 , Z=-1/R2*C1
The pole at G node : -1/2g*Cgs (1/2g=5k , Cgs=200P)
The dominate pole at the Vo : -1/Ro*Co ( Ro=50k , Co=10u)
I think C2 is to increase the speed of the loop . It may not for...
usually u use a large offchip cap. at the output node making the output node the dominant pole , or if u don't want offchip component u use other compansation techniques (like miller , nested miller or whatever)to make the output of the error amp. the dominant pole
------ NONSENSE
Hi :
For stability ,it is required that the output cap must be greater than a value ,but
the ESR is not needed . So is it output cap compensation and the output pole is
the dominant pole ? But in it's shcmatic , it is like that a node in the errorAmp
is made the dominant pole for there is...
Re: Need ur help !
"In my opinion,
1) Q1,Q95 are level shifter
2)Q93 is a emitter-follower,
3) C4 & C5 are not compensation cap. because those nodes they connected are all low impedance nodes. so r*c is too small, u can run a AC simulation to check this.
" -----------SAY AS SAY NOTHING !
Hi ,everyone :
Would anyone tell me the functions of the C4,C5,and bipolar transistor Q93 ?
This circuit is a buffer used in a LDO .
Added after 1 minutes:
Sorry , the image is too little . I post the link here :
Added after 46 seconds:
https://obrazki.elektroda.pl/10_1175502808.gif
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