I planed constant power load control circuit. All parts are fully operational in computer simulation. But I want to Isolate High voltage (180V DC ) DC ground (GND 2) and low voltage (12V/3.3V DC) DC Ground (Gnd) What can be done for this? How to solve this problem?

 

Opto Isolator for Mosfet Q1 common

 

cant use Opto Isolator

 

cant use Opto Isolator

Why not.
That's the obvious solution to your problem.

So are there any other isolation methods you can't use?

 

Why not.
That's the obvious solution to your problem.

So are there any other isolation methods you can't use?

This circuit works very well when one part is taken.
The system works very well when all ground are connected.
This system is flawless.The current controlloing is very smooth and stable.
The current flowing through the shunt could also be measured very accurately.
So there are no errors in it,
I took the help of EEv bolog, Greatscoot, electronoobs YouTube channels for this. There are no errors. But

this circuit has 3 main units

1) esp32 DAC --> non inverting amp gain is 4 (12 V DC )
2) current control loop (185V DC )
3) measure shunt voltage --> non inverting amplifier to gain 6 ( 3.3V DC) --> esp 32 ADC

These three sections are powered by under different voltage levels! I want isolate Grounds of 12V and 185V for safety.
Is it possible to use ground isolation like B1212 or any other method for this ?

how to use optocoupler/opt isolator for DAC output and current measuring ADC input ?

 

Opto Isolator for Mosfet Q1 common

Plus Hall-effect device to measure the current.

 

This circuit works very well when one part is taken.
The system works very well when all ground are connected.
This system is flawless.The current controlloing is very smooth and stable.
The current flowing through the shunt could also be measured very accurately.
So there are no errors in it,
I took the help of EEv bolog, Greatscoot, electronoobs YouTube channels for this. There are no errors. But

this circuit has 3 main units

1) esp32 DAC --> non inverting amp gain is 4 (12 V DC )
2) current control loop (185V DC )
3) measure shunt voltage --> non inverting amplifier to gain 6 ( 3.3V DC) --> esp 32 ADC

These three sections are powered by under different voltage levels! I want isolate Grounds of 12V and 185V for safety.
Is it possible to use ground isolation like B1212 or any other method for this ?

how to use optocoupler/opt isolator for DAC output and current measuring ADC input ?

Why won't you answer the question? Why is using an opto-isolator on Q1 "not possible"? It beats driving the gate of that MOSFET with a wimpy opamp like the LM324.

 

hi ranganat,
Is this a College assignment project.?
Moderation.

 

The circuit works fine. The system works very well when all ground are connected.

.

watch this test result !
https://www.youtube.com/shorts/oaF8soCysAA
https://www.youtube.com/shorts/xBlz2WFeGcY

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@Papabravo how? and what is your suggestion ?

this circuit has 3 main units

1) esp32 DAC --> non inverting amp gain is 4 (12 V DC )
2) current control loop (185V DC )
3) measure shunt voltage --> non inverting amplifier to gain 6 ( 3.3V DC) --> esp 32 ADC

These three sections are powered by under different voltage levels! I want isolate the Grounds of 12V and 185V (gnd and gnd 2) for safety
thanks

@ericgibbs Is this a College assignment project.? NO

 

...
@Papabravo how? and what is your suggestion ?
...

You still have not answered the prime question which has been asked of you. Way can't you use an opto-isolator? You have flung a torrent of irrelevant material against the wall to see if anything sticks. Your obstinate refusal to answer that question will inhibit the quality of the advice you receive. That said I will answer the question that you posed.

The gate of a MOSFET looks like a BIG capacitor. You need a substantial amount of current to move charge onto and off of the gate. The reason you want to do this is to avoid the losses that you will incur if you spend any appreciable amount of time with the gate holding the MOSFET in the linear region between the extremes of the switching signal. The LM324, or any similar opamp does not have the slew rate or the drive capability to do that. You want a push-pull driver that will charge and discharge the gate as rapidly as possible.

I gave a direct answer to your question, how about giving me the courtesy of a direct answer to my question.