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Design >> Analog Design >> Could you let me know this type of circuit ?
https://designers-guide.org/forum/YaBB.pl?num=1364454518

Message started by azure_sky on Mar 28^th, 2013, 12:08am

Title: Could you let me know this type of circuit ?
Post by azure_sky on Mar 28^th, 2013, 12:08am

I am reading some book but dosen't know a circuit.

1) What type of this Internal supply voltage regulator is ?
2) What is pros and cons for this circuit
compared with simple 1-stage regulator which is usually used ?
3) What materials can I read for that ?

If you let me know that, it will be very helpful for me.

Thank you for reading this.
Have a nice day.

Title: Re: Could you let me know this type of circuit ?
Post by loose-electron on Apr 24^th, 2013, 8:48pm

quick look --
its an OTA setup in unity gain feedback mode, without gain-phase compensation capacitor.

Title: Re: Could you let me know this type of circuit ?
Post by azure_sky on Apr 24^th, 2013, 9:50pm

Thanks a lot.
Anyway, I knew this type is OTA like last week.
But I still don't know whether this type of voltage regulator is widely used.
Have you ever seen this at voltage regulator ?
Another question is if OTA diff. source is not controlled by current source,
what problem would happen ?
I saw some OTA diff. doesn't have current source.

Title: Re: Could you let me know this type of circuit ?
Post by boe on Apr 25^th, 2013, 9:13am

Azure_sky,

Quote:

Another question is if OTA diff. source is not controlled by current source,
what problem would happen ?
I saw some OTA diff. doesn't have current source.

In this case you usually want a circuit that is sufficiently close to a current source in the region of interest.
- B O E

Title: Re: Could you let me know this type of circuit ?
Post by loose-electron on Apr 26^th, 2013, 10:22am

LDO regulators can be configured in this manner. Again, there is no stability compensation shown.

Title: Re: Could you let me know this type of circuit ?
Post by azure_sky on Apr 26^th, 2013, 7:11pm

Even though the above circuit doesn't have the stability capacitor,
the actual circuit have the stability capacitor and leakage source.
The leakage source is connected to the output load.
The leakage source is better than the stability capacitor
according to the simulation.
Is it true ?

Title: Re: Could you let me know this type of circuit ?
Post by tzg6sa on May 2^nd, 2013, 5:15am

azure_sky wrote on Apr 26^th, 2013, 7:11pm:

What do you mean by leakage source? This term sounds strange to me.
The picture is just showing the architecture of the amp. it might be possible that you need a cap, and also in the real life the output would be cascoded for higher gain. The pictures in the books are not showing the final circuit, they just show the circuit's structure and everything which is not necessary to understand the circuits operation is left out for the sake simplicity and better understanding of the fundamentals.

Title: Re: Could you let me know this type of circuit ?
Post by azure_sky on May 2^nd, 2013, 8:18am

The circuit which I mentioned as leakage source is the static current load.
I have the circuit similar to the above circuit.
It had the compensation capacitor and the static current load,
but doesn't have the cascode for the higher gain.
So I wonder whether the cicuit is a good circuit and
the necessity for changing this circuit to another type of circuit.

Title: Re: Could you let me know this type of circuit ?
Post by loose-electron on May 2^nd, 2013, 11:46am

azure_sky wrote on May 2^nd, 2013, 8:18am:

The question is vague, what are you trying to do?

Answer that and then can determine if good or bad

Title: Re: Could you let me know this type of circuit ?
Post by azure_sky on May 2^nd, 2013, 5:44pm

As I mentioned at the above main article,
I'd like to change this type regulator to the simple diff. amp type regulator
if the latter is better than the former.
So I wonder which one I select.