Blackuni
Full Member level 4
Hi
can some one tell me how the loop gain increase with low/zero current with an LDO(refer to the attached screen shot) up to my understanding this should be other way.
Say for example i have a three stage LDO structure with gain Aopen= A1 x A2 x A3(pass transistor)
and my feedback factor beta = Rf1/(rf1+rf2) so my loop gain will be Lgain = Aopen x beta
As per my expectation when current goes to zero/low my A3 will reduce. If A3 is reducing then total open loop gain as well as loop gain will reduce. but how its other wise?
thanks,
can some one tell me how the loop gain increase with low/zero current with an LDO(refer to the attached screen shot) up to my understanding this should be other way.
Say for example i have a three stage LDO structure with gain Aopen= A1 x A2 x A3(pass transistor)
and my feedback factor beta = Rf1/(rf1+rf2) so my loop gain will be Lgain = Aopen x beta
As per my expectation when current goes to zero/low my A3 will reduce. If A3 is reducing then total open loop gain as well as loop gain will reduce. but how its other wise?
thanks,