Pls help to comment on these 5 types of current mirror reference generator biasing circuit shown in the attachment. Which one is most suitable for biasing differential amplifier tail? Figure of merit e.g. Constant gain across process and temperature variation, low input offset voltage for comparator etc.
Pls show me if there is other better biasing circuit.
accordin to me bandgap current biasing is the best.... as it is immune to temperature variation and the other things that you have mentioned can be achieved using it....
I agree. sometimes We need PTAT bias current to compensate the high temp characteristic of opamp. But if your circuit need temp stable character, I think the bandgap biasing is good.
So, I think which type of biasing is to be used should rely on your requirement.
Can you point me to some bandgap reference current generator for biasing? I only have bandgap voltage generator (Brokaw), but using I/V converter to generate bandgap current this way will produce error because of resistor tolerance.
Bias1,2,3 rarely find usage for current bias according to big variation as VDD changing, temperature variation and process fluctuation. VDD changing is the more serious one among them. Vgs2+Vgsn=VDD. And Id is related to (Vgs-Vth)^2. However, they might still be used in some case that bias is required to be depended on VDD.