Voltage Regulator Layout

Thread Starter

JulesP

Joined Dec 7, 2018
374
Hi all,

I asked someone to design a regulator capable of 50A which is shown in Pic 1 (a simulator schematic in EasyEDA) with a close up of one part in Pic 2. For each of the slave and the master regulators they have 'IN' and 'MASTERIN' as shown as blue Net Ports. When I came to divide up the circuit into several boards with actual connectors, as shown in part in Pic 3, I have H2 as the input from the voltage source that is being regulated to supply both 'IN' and 'MASTERIN' for all the regulators.

The red arrow in Pic 3 shows the feed to 'MASTERIN' taken off the feed line to 'IN' but which I noted would act as a short around 0.1R4. Pic 4 shows an alternative connection. The designer said this was wrong and referred me to their original layout (Pic 1) but did not say how I should lay it out instead. Since then I have been unable to communicate with them and I can't proceed with the PCB layout until this issue is resolved.

The only source I have for these two inputs is the + voltage line from my PSU so my query is, how can I differentiate the two inputs 'IN' and 'MASTERIN' when they are connected to a common source and are therefore electrically part of the same net?

I'm sure the answer is very simple but to someone not trained in this area I can't see it. :oops:

Pic 1.jpegPic 2.jpegPic 3.jpgPic 4.jpeg
 

Thread Starter

JulesP

Joined Dec 7, 2018
374
Not sure what the linear means here but as each regulator can only handle 5A it needs 10 to cope with 50A max
 

Deleted member 440916

Joined Dec 31, 1969
0
It means using the linear region of a series pass device or like a resistive element to drop the voltage rather than a switching element and low pass filter. In short a very simple buck switcher would do your job with reletively little power dissipation.
What are your input and output voltages ?
 

Thread Starter

JulesP

Joined Dec 7, 2018
374
My experience with buck converters (different from a switcher?) is that they can't handle much current.
My input is 12V and I need to adjust that between 6-10V with a max current of 40-50A (normally 25-30A)
I also need the same regulator to work with a 9V supply to be able to adjust that to 5-7V.

As I have invested a lot of time and effort into this regulator and believe it will do the job I would prefer not to scrap the idea but solve the probably very simple query unless I can guarantee a better alternative.
 

kennybobby

Joined Mar 22, 2019
75
Do you have the equipment to measure and adjust the resistance of the cross-connections to within 0.001Ω, which is required per the notes? Otherwise the 10 parallel elements will not share current evenly and will be fighting against each other.

This is not a very robust design with such stringent and unlikely possible requirements across so many elements.

The regulator is being operated at the very maximum current of its rating with no margin, there are no capacitors on the outputs, heat sinks will be required (45W per regulator), etc. Good Luck.
 
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Thread Starter

JulesP

Joined Dec 7, 2018
374
No but my approach there is to make sure the track lengths are about equal. I’ve asked around on this site before and no one came up with a suitable regulator option. My typical max current is 30A.

If there is an easier option then I’d be happy to hear it.
 

kennybobby

Joined Mar 22, 2019
75
What is the source of your 12V and 9v supply? What is the impedance characteristics of the supply? Is it a battery bank, what is the capacity? What is the operating time or mission duration for the supply? etc. There are many aspects of the requirements that would need to be identified for anyone to have any idea where to begin.

And nobody works for free, a serious project requires an investment of time and money. If you can't diy, then you will have to pay someone if you want a design that works.
 

Thread Starter

JulesP

Joined Dec 7, 2018
374
What is the source of your 12V and 9v supply? What is the impedance characteristics of the supply? Is it a battery bank, what is the capacity? What is the operating time or mission duration for the supply? etc. There are many aspects of the requirements that would need to be identified for anyone to have any idea where to begin.

And nobody works for free, a serious project requires an investment of time and money. If you can't diy, then you will have to pay someone if you want a design that works.
I gave all this information to the person who designed the regulator and paid for it so I’m not keen to go through all that again.
Is there an off the shelf device that can do this. An earlier member mentioned a Buck Switcher?

It’s because I don’t wish to pay twice etc for another design that I’m hoping for the simple answer to my query regarding the IN and MASTERIN inputs of the regulator as per my initial post.
 
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kennybobby

Joined Mar 22, 2019
75
Sorry to hear, it would appear that they never built one or have any design experience. The really goofy feature is trying to adjust the output voltage by comparing the input voltages with an op amp..? i can see the potential for instability and ringing in the op amps with that approach.
 

Thread Starter

JulesP

Joined Dec 7, 2018
374
Sorry to hear, it would appear that they never built one or have any design experience. The really goofy feature is trying to adjust the output voltage by comparing the input voltages with an op amp..? i can see the potential for instability and ringing in the op amps with that approach.
I’m feeling the ring of doom on that design. Perhaps a 500W Buck converter from Banggood or similar might suffice?
 
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