Try to design a 12 volt linear output circuit which have wide input range(24v to 100v)

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Pradeep.etce

Joined Jun 28, 2023
16
Hi everyone,
for last one month i am working on a power circuit, the constraints are input - 24v to 100v and output-fix 12V/1.5A max. The problem is i need to design a voltage regulator circuit. We don't have the much size on pcb for make buck converter and we need to minimize the cost. I looked a voltage regulator IC name LR__ but the current rating of that ic is very low. And if i use LM317HV then i am not sure about circuit and its input range. Please help me to design a voltage regulator which input is 24v to 100v and output is 12v/1.5amp max. Is any regulator ic available in this range ?
 

StefanZe

Joined Nov 6, 2019
191
Use a buck regulator. The buck regulator will be smaller than a standard IC regulator and i don't think you will find a IC with the specs you want. Maybe there are DCDC modules or buck converter modules you can use, but these are not cheap.

But a linear voltage regulator won't work because of the high power dissipation of (100-12V/1.5A = 132W)
 

Thread Starter

Pradeep.etce

Joined Jun 28, 2023
16
but a buck regulator ic in that wide range is not cost efficient and if any then is not available in local markets. I checked some ic which not available in India's market (xl7036, lm5012, lm5013, L3751PUR) these ics are not available. And i design buck converter using UC3845 ic but, I can't use it due to less size on PCB. the required size on pcb is only 30mm*33mm. Please suggest me what i need to do.
 

Ian0

Joined Aug 7, 2020
10,005
but a buck regulator ic in that wide range is not cost efficient and if any then is not available in local markets. I checked some ic which not available in India's market (xl7036, lm5012, lm5013, L3751PUR) these ics are not available. And i design buck converter using UC3845 ic but, I can't use it due to less size on PCB. the required size on pcb is only 30mm*33mm. Please suggest me what i need to do.
Spend the money!
Not only will be buck regulator be smaller than the heatsink required for a linear regulator, it will be far cheaper than the heatsink.
 

StefanZe

Joined Nov 6, 2019
191
I think a buck regulator is your only option with the design requirements you have. If this is not an option there is a possibility that there are no options that will satisfy your requirements
 

Ya’akov

Joined Jan 27, 2019
9,233
okey, but i am still trying to figure out the solution. if you know some or found something then please let me know.
If your product has contradictory requirements you can’t build it. You have to decide what you need, that is, which constraint is the most important. You are up against physics here. You “don’t have the space” so you can’t have that much power with the voltage range you are trying to also get.

Which things are actually constraints and which are more flexible. Something has to be changed in order to do what you want. As it stands you can‘t put 12V@1.5A from 24-100V into a space as small as you say you have. Everything you try will result in something bad about the outcome.

You have to change something and engineering involves that optimization process. There is a popular aphorism about this:

fast, cheap, good—pick any two

This is the problem of optimization in a nutshell, you can’t max out every part of a design, you have to choose where to “compromise”. But don’t think of it that way, think of it as optimizing the final design. Keep the functional goals of the design in mind, don’t confuse the wish list as the design itself. One of the parameters of the design is that is be possible to build.

What happens in a case like this is that areas you aren’t even attending to, such as service life, suffer and the project fails after it “succeeds”. For example, say you decided on a linear regulator. As has been pointed out by @Ian0 such a route would require a massive heatsink—to be reliable. Let’s say you don’t put a heatsink on the part because “you don’t have space”.

The regulator will overheat, failing from overheating and/or damaging nearby components and/or damaging the PCB and housing. This is not a successful design even if you get 12V@1.5A before this happens because just as important as the size of the PCB and the input and output ranges is the reliability and service life.

To solve this problem, you have to fix your design, which means fixing your specification that demands ”fast, good, and cheap” which the strict limits of physics don’t allow.
 

Thread Starter

Pradeep.etce

Joined Jun 28, 2023
16
If your product has contradictory requirements you can’t build it. You have to decide what you need, that is, which constraint is the most important. You are up against physics here. You “don’t have the space” so you can’t have that much power with the voltage range you are trying to also get.

Which things are actually constraints and which are more flexible. Something has to be changed in order to do what you want. As it stands you can‘t put 12V@1.5A from 24-100V into a space as small as you say you have. Everything you try will result in something bad about the outcome.

You have to change something and engineering involves that optimization process. There is a popular aphorism about this:

fast, cheap, good—pick any two

This is the problem of optimization in a nutshell, you can’t max out every part of a design, you have to choose where to “compromise”. But don’t think of it that way, think of it as optimizing the final design. Keep the functional goals of the design in mind, don’t confuse the wish list as the design itself. One of the parameters of the design is that is be possible to build.

What happens in a case like this is that areas you aren’t even attending to, such as service life, suffer and the project fails after it “succeeds”. For example, say you decided on a linear regulator. As has been pointed out by @Ian0 such a route would require a massive heatsink—to be reliable. Let’s say you don’t put a heatsink on the part because “you don’t have space”.

The regulator will overheat, failing from overheating and/or damaging nearby components and/or damaging the PCB and housing. This is not a successful design even if you get 12V@1.5A before this happens because just as important as the size of the PCB and the input and output ranges is the reliability and service life.

To solve this problem, you have to fix your design, which means fixing your specification that demands” fast, good, and cheap” which the strict limits of physics don’t allow.
Thanks for your suggestion, sometimes i am think same as you, but then realize, we are engineers and we can make things better than previous, we are only which make them possible. May be sometimes we have to compromise. But i will work on it by keeping your suggestion in mind.
 

Ya’akov

Joined Jan 27, 2019
9,233
Thanks for your suggestion, sometimes i am think same as you, but then realize, we are engineers and we can make things better than previous, we are only which make them possible. May be sometimes we have to compromise. But i will work on it by keeping your suggestion in mind.
You can certainly innovate, but you are not innovating in this case you are trying to find a workaround for the laws of physics. Thermodynamics isn’t just a suggestion, it’s a hard limit.
 

Thread Starter

Pradeep.etce

Joined Jun 28, 2023
16
You can certainly innovate, but you are not innovating in this case you are trying to find a workaround for the laws of physics. Thermodynamics isn’t just a suggestion, it’s a hard limit.
Yes, as i told you, i was think same as you but now, i am working with a Person who changed the laws of physics. He is my Ideal. Mr. Ajay Chaudhary, He design a system whose output is more then input, eg. if a machine takes 100watt power for run in input and that machine gives 150 watt in output. They a have patent right in 179 countries for this technology. He is specialist in internal energy generation, and he starts a company name Sahil research and technology pvt. ltd. Thats the region i am looking for all possible ways to reach our output.
 

LowQCab

Joined Nov 6, 2012
4,196
Putting ~100-Volts DC on to a small Circuit-Board, in a small space, is just begging for a disaster.

Regulate the Voltage down to ~24-Volts BEFORE it gets to the Circuit-Board, with an ISOLATED SMPS,
then regulate it down again with a Buck-Converter for ~12-Volts.

~100-Volts to ~12-Volts is almost a ~10-to-1 Voltage-Ratio,
this can not be done efficiently with a single Buck-Converter.
A Transformer is required, and the Input and Output must be fully isolated.
.
.
.
 

Ian0

Joined Aug 7, 2020
10,005
I circuit includes microcontroller, relays, mosfet, and leds and resistors only.
Its maximum load. normal load will be 12V/0.5A, i pick the peak load is 12v and 1.5 ampere.
12V @ 500mA for processor relays and LEDs sounds to me as though it could be reduced further.
If you can reduce it to 100mA you can use this
https://www.analog.com/media/en/technical-documentation/data-sheets/3639fd.pdf
Can you use lower current relays? Could you use latching relays?
Can you run the LEDs at lower current?
Can relays be replaced by MOSFETs?
Are you adding up the power of two relays when only one could possibly be energised at any one time?
Could you step down to 24V @ 100mA and use 24V relays (even a standard one only uses 17mA), then use another buck regulator to get to 3.3V/5V for the processor and LEDs?
 

Ya’akov

Joined Jan 27, 2019
9,233
Yes, as i told you, i was think same as you but now, i am working with a Person who changed the laws of physics. He is my Ideal. Mr. Ajay Chaudhary, He design a system whose output is more then input, eg. if a machine takes 100watt power for run in input and that machine gives 150 watt in output. They a have patent right in 179 countries for this technology. He is specialist in internal energy generation, and he starts a company name Sahil research and technology pvt. ltd. Thats the region i am looking for all possible ways to reach our output.
I’m sorry but I can’t help you at all. I suggest you don’t talk about overunity devices here as that is explicitly against the rules. Good luck with your project.
 

Papabravo

Joined Feb 24, 2006
21,258
Yes, as i told you, i was think same as you but now, i am working with a Person who changed the laws of physics. He is my Ideal. Mr. Ajay Chaudhary, He design a system whose output is more then input, eg. if a machine takes 100watt power for run in input and that machine gives 150 watt in output. They a have patent right in 179 countries for this technology. He is specialist in internal energy generation, and he starts a company name Sahil research and technology pvt. ltd. Thats the region i am looking for all possible ways to reach our output.
This is what we call magical thinking. It leads to only one place and that place is called disaster. You can follow this road if you choose, but you don't get to complain that you were not warned.
 

Ian0

Joined Aug 7, 2020
10,005
He design a system whose output is more then input, eg. if a machine takes 100watt power for run in input and that machine gives 150 watt in output. They a have patent right in 179 countries for this technology. He is specialist in internal energy generation, and he starts a company name Sahil research and technology pvt. ltd.
Patent numbers, please.
 
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