Voltage Regulator Design with Op Amp and BJT Transistor

[@wafikiri_]

I've always liked those Darlington arrangements.

[@STEMprof]

Thanks for watching. Glad that you also like the famous Darlington transistor formation. I will try to post more on Darlington.

[@kennmossman8701]

but did you know there are two types

[@tanmayvadhera4250]

@@kennmossman8701 The other one is the Sziklai pair : )

[@STEMprof]

​​@@kennmossman8701​Thanks Kenn for watching and your comment. For more examples pls see:
Flexible Voltage Regulator: th-cam.com/video/CJl-urzeiTo/w-d-xo.html
And a Bandgap Video: th-cam.com/video/esMlNx5w9Jw/w-d-xo.html
I will soon post videos on Darlington and Sziklai Pairs.
I hope these Analog Circuit Design and Analysis Examples are interesting and helpful. Thank you.

[@STEMprof]

​@@tanmayvadhera4250Thanks Tanmay for watching and your comment. I will soon post videos on Darlington and Sziklai Pairs. Here is another Voltage Regulator Example: th-cam.com/video/CJl-urzeiTo/w-d-xo.html
And a Bandgap Video: th-cam.com/video/esMlNx5w9Jw/w-d-xo.html
I hope these Analog Circuit Design and Analysis Examples are interesting and helpful. Thank you.

[@STEMprof]

Thanks for watching. For more Analog Computer & Op Amp examples please see: th-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html
Flex Voltage Regulator Example: th-cam.com/video/CJl-urzeiTo/w-d-xo.html
Voltage Regulator Design with BJT Darlington Transistors and Zener Diodes th-cam.com/video/ArisQp7V0Ac/w-d-xo.html
Bandgap Video: th-cam.com/video/esMlNx5w9Jw/w-d-xo.html
Sawtooth Oscillator with Op Amp, JFET and BJT Transistors th-cam.com/video/5zHXTx-Vl20/w-d-xo.html
Op Amp Analog Computer circuit that solves Differential Equation: th-cam.com/video/ENq39EesfPw/w-d-xo.html
Full-Wave Rectifier: th-cam.com/video/DJJMNU-CYcg/w-d-xo.html
I hope these Analog Circuit Design and Analysis Examples are interesting and helpful. 🙏

[@electroquests]

Hello, I really appreciate you making this video! I have been trying to make a CC and CV power supply using BJTs and opamps for years now. I am puzzled by the crazy feedbacks other than the compensation networks, can you please make videos on those topics as well. I'm really passionate about electronics but I need help from an expert like you

[@STEMprof]

Thanks Anurag for watching. Glad that this voltage regulator video is helpful. Pls watch this flexible regulator example th-cam.com/video/CJl-urzeiTo/w-d-xo.html and let me know if it is helpful regarding your question or not.
Please let me know more details about what exact type of feedback scenarios are you looking for so that I do my best and find the best example to help you.

[@electroquests]

@@STEMprof Thank you for your quick response, I really appreciate it.

[@STEMprof]

Thanks again for watching. Hopefully the new Voltage Regulator Design with Current Foldback feature th-cam.com/video/RFfRrbqM_-s/w-d-xo.html is interesting and helpful. 🙋‍♂️

[@George10767]

There are two separate systems here. One controls the output voltage, the other senses an over-current fault condition. There are ways of presenting a schematic in which the principles of the functions are immediately clear.
I have the gut feeling that there is too much amplification and this might threaten stability. The "Darlington" transistor connection has enormous gain and op-amp 2 (used as a comparator) has an uncontrolled gain with decreasing frequencies. The presence of a 10 uF capacitor across the output might suggest that there was initially a problem with stability, and the capacitor was necessary to "hold it down".
I would expect a modern design to use a power FET instead of a bipolar transistor.
In a fault condition, the load resistance may be *any* value less than the specified RL but greater than zero. Can it be shown that the power dissipation in transistor T1 would be less than the maximum allowable under *all* values of RL ?

[@STEMprof]

Thanks for watching and sharing your thoughts about this voltage regulator circuit. Yes, modern regulators use power FETs instead of power BJTs. This is just an example utilizing BJT. Maximum power of the power transistor is maxCurrent*(maxSupplyVolt - EmitterVolt) ~= 2.16A * (25V - (2.16A*1ohm + 15V)) ~= 16.94 Watt. Therefore the Power transistor is recommended to be a 20 W transistor in this example.

[@Scientific-curiosity]

thanks you for your time. may you do videos on Op Amp Signal Conditioning

[@STEMprof]

You are welcome, thanks for watching. Please see this youtube link th-cam.com/video/Bw29QjHHzGo/w-d-xo.html that talks about differential amplifier for signal conditioning.