Dear all,
In design of Low Drop-out Voltage Regulator (LDO), what type of opamp should be used?
I usually design LDO with folded cascode opamp and it seems to get matched with the requirement.
Anyone can give a short conclusion for choosing the opamp topology used in LDO?
Really appreciate your supports,
Sincerely
The selection of opamp topology for an LDO largely depends on the gain you are targeting for and the supply voltage available to you for maintaining the voltage headroom. However to answer your question in a more general way, I would like to say, there are many opamp topologies available. As you have mentioned one of them 'Folded cascode'. Apart from this you can use differential amplifier with active current mirror. To increase the gain you can also use two stage amplifiers and so on.. The list continues.
Sanat
You may want to ask this question on e2e.ti.com
Also see the book:
http://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf
I suggest to search for any internal LDO circuit diagram for the reference. There are more (LM317..) or less (LM2941) detailed schemes of LDO internal topologies available in some datasheets. I hope that direction could be of help.
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