raja.cedt wrote on Nov 5th, 2008, 10:04pm:................................
But i have one basic question regarding stability,how to know which loop is causing problem(because in our problem we have around 2 -ve feedback,1 +ve feedback).is there any way to figure out this problem
Hi raja.cedt
I do not know much about your circuit (and the beta-helper stuff), but your last question touches control theory.
And from this I know, that it is a basic problem to know which loop causes problems if the whole system contains more than one feedback loop. Normally, one can say that the SLOWEST loop determines to a great extent the system behaviour - that means it is the "dominating" loop. But in some cases this does not help because it is not always possible to discriminate between "local" and "over all" loops.
More than that, opening one loop can sometimes make the system unstable.
In summary, as far as I know there is no general rule in control theory which allows us to find the most critical loop in a multi-loop structure.
Regards