[Solved] How to find voltage regulator for 3.3V or 5V at 3A to 5A

Posted by: @ronalex4203

@will Perhaps I should have put in my profile that I am prone to 'thinking out loud' and I typically do any design work at least 5 times, code 3 times. My previous post had a typo that you compensated for, I meant to say 5V @ 10A. That is actually too high. Here is the latest design objectives.

1. BIG ATX style 450W mains powered. 12V @ 36A, 3.3 and 5 at 20A but total wattage is 110W

2. Medium laptop brick supply, 19V @ 4.74A in, 3.3 and 5 at 3A, 12V @ 5A

3. Light portable either 9V battery, same brick as above and now thinking of using my 20,000mAh Anker brick to produce 3.3, 5, and 12V @ 1A, more on the 12 if possible up to 3A.

I just got educated by Bill on Buck/Boost devices so using the high AH 5V power brick might work for driving at least 1A at 12V for about 90 minutes.

So how do I find the device that will work from 20V to 4V input and put out 12V?

I was hoping to hear that there is a web site that I plug in my knowns and it gives me a list of choices.

If I recall correctly (IIRC), you're just starting off again on electronics, so I'd suggest that you start at the small end and just use the battery and a couple of inexpensive LM2596 set to 3.3V and 5V and play around to get familiar with the components and micro-controllers and wait until you need to move to a bigger supply 9either in voltage or current).

It's nice to have everything available at once, but if you really feel that you need an all-in-one solution, then I'd suggest that you look at a commercial power supply, or at least one of the more expensive converters that allow you to set voltage and current limits.

They'll give you a range of voltages and currents and will provide extra safety in the form of short circuit protection and other advantages like constant current and constant voltage and limiting both.

For instance, suppose you have a brand new electronic cure for cancer that takes 5V and runs on an Arduino so it should take less than 100mA. You could set up the power supply to deliver (at most) 5V and 100mA.

If you have an undiscovered short, the power supply will limit the power input and you can shut the supply and the device off. If you use one of the inexpensive devices, you'll be spending some time digging parts out of your walls (and maybe your face as well).

As far as I know, there's no ONE site where you can go and plug in your requirements and have it look up the device you need.

Posted by: @ronalex4203

@jker Sorry, I don't get it. What do you mean when you say 'unintentionally creating an antennae in your wiring.'?

The most common effect of noise on a power rail is broadcasting that noise frequency into the surrounding air (and nearby components). This is basically what people are talking about when we talk about EMI-ElectroMagneticInterference. This depends on your antennae length (wire length) and is another reason that professional PCB designers will often prefer linear regulators to switching regulators when they are appropriate (low current and reasonable voltage drop applications).

Unfortunately, this is not in any way "simple". EMI control is something of a black art even among professional circuit designers.

EDIT: I'm reading a bit of the surrounding context.  I highly recommend you don't worry too much about this type of thing at this stage. I am _mostly_ talking theory and "one step closer to the real world" here... not giving practical advice on what you should do.

I get along very well with an ATX power supply adapted as a power supply, a 24V 10A boost converter, and a pile of simple buck/boost converters and linear regulators.

@will I did find a couple of sites that sort of do what I want but some of the inputs are not known to me. Now that I know the BUCK/BOOST are the way to go at least power wise then that makes things simpler. Also the suggestion for reducing noice by adding a LVR seems like a good idea.

As far as starting slow, I feel I am. All 3 of the PSU's are either almost off the shelf or based on Bill's designs. I am just adding 12V to the medium and small since my RV is a 12V device. Having in one box both the control voltages, and the supply voltage is extremely handy. 

The designs are trivially simple, but I have added fuses on ALL power lines even the ATX supply. I appreciate your concern, but I have been an industrial electrician, re-done most of the power wiring in my RV, installed my own solar and inverter with enough power to burn off appendages (600A max), re-wired my RV main electrical power, added several 110 circuits and when I had a house re-wired and added circuits galore. I am new to the solid state devices, but not new to power.

@ronalex4203 

I didn't mean to belittle your experience or capability, I'm very sorry if I gave you that impression.

@jker That is what I suspected. As far as 'into the air' why not add a Faraday cage around the offending component and of course if it is causing issues on the rail, add the LVR. Then there is the real cheap solution of simply maximizing Distance as in 1/(D*D)

@will NO NO, I really do appreciate your concern, and as a result I will be a lot more careful but I do have experience and have a bit of a reputation for being too careful. When I was an industrial electrician I would never touch anything without my voltmeter probes first checking. I have been known to check ground to ground, I suspect EVERY possible path. I am talking about stuff that requires the service guy to remove all metallic objects before getting close or inside the enclosure or MG set. We did tool counts in and out. Once we had to stop work because the tool count was off by one and the lead hand was on his way home (decades before cell phones) and had to wait until he got home. When we got a hold of him he did have a screwdriver in one of those elongated side of the pants pockets.

Posted by: @ronalex4203

@jker That is what I suspected. As far as 'into the air' why not add a Faraday cage around the offending component and of course if it is causing issues on the rail, add the LVR. Then there is the real cheap solution of simply maximizing Distance as in 1/(D*D)

I can't answer this authoritatively, but I think that basically is the solution for commercial switching power supplies. (I work with EEs, but am not one myself) Every ATX or ATX-like power supply seems to be enclosed as such.

Of course, this is a different situation when you are talking about a set-top box or other component that will have regulators and "operational" components on the same board. My impression is that figuring out crosstalk issues on sensitive lines (edit: mostly NOT power rails) takes up an inordinate amount of effort on the part of engineers in this area.

@jker @will I just noticed that the LM2596 adjustable module is only 73% efficient. Isn't that quite different from the 95% I have seen quoted for other VR's.It looks like the LM33630 is replacing it (ULTRA-LOW EMI), any experience?

2nd question, I have one of those 20,000mAh USB power blocks from Anker. I would like to use that for a portable 12V supply (RV's have a lot of 12V stuff) It probably needs to go lower than 5V in unless the Anker has LVR output which makes sense given the std cell voltages are not 5. I found an MT3608 that looks like it might work but it is peak 2A and 1A sustained. That might not be enough, too many unknowns for me to know for sure as I am building this on spec, no particular use case in mind.

@ronalex4203 

I have no experience with the LM33630 nor the USB power block.

I'd suggest that you decide on a project, design the circuit and then select the power source based on the project's needs, that's what I always do.

@will I am sortof. I just figured out the ATX power supply connections. Very cool, I have a always on 5V for meter power, a ready and power good signal for green and red LED's. In tis case because I want 3 power supplies all with 3.3, 5, and 12V powered by mains, laptop brick, battery or laptop brick I have a lot of common requirements and similar parts. The ATX supply is what it is, the laptop brick is sort of limited to 3A to 5A and the portable is 1A except for the 12V which should probably be closer to 3 but that's a guess.

After all that, I have been and just today are breaking this giant project up into bite sized pieces. The wait time on switches is the worst, they are still 2 weeks out. 

As I was just entering this I realized I was doubling up on one requirement so that simplifies things some.

@ronalex4203 

Yeah, stuff never gets here fast enough 🙂

What have you picked as your first project, the basement door light ?

@will After I have the power supplies built and the ESP32-CAM test bed, yes I will start on the basement intrusion, 'left the door open' signal/telegram? and yes, turn on the light.

I have been reviewing the magnetic reed solution, and realized the issue I had is that the switches are not oriented correctly. I am re-posting the two pictures. The hatch fits inside the frame where you see the weather stripping in the first picture. Basically the 2 devices are NOT facing each other, they are beside each other. If I could find the right sized 90 bracket I cold orient them properly, but the risk is if they protrude very much they will get ripped off. I don't know if you can visualize it from the pictures, maybe if I climb inside to take a picture after the door closes?

I was watching a YT vid from DBWS showing some newish radar and Lidar sensors that might be useful too. Remember, the mag door switch only tells me the door opened, is still open and closed. It can't tell me about movement in or near the opening. I want all the above and am very comfortable with that kind of coding.

Posted by: @ronalex4203

@will After I have the power supplies built and the ESP32-CAM test bed, yes I will start on the basement intrusion, 'left the door open' signal/telegram? and yes, turn on the light.

Sounds good.

I have been reviewing the magnetic reed solution, and realized the issue I had is that the switches are not oriented correctly. I am re-posting the two pictures. The hatch fits inside the frame where you see the weather stripping in the first picture. Basically the 2 devices are NOT facing each other, they are beside each other. If I could find the right sized 90 bracket I cold orient them properly, but the risk is if they protrude very much they will get ripped off. I don't know if you can visualize it from the pictures, maybe if I climb inside to take a picture after the door closes?

I understand the problem and now it makes sense why you're unhappy about them. If they're not facing correctly, then the leaves of the reed wouldn't align with the magnet and the results would almost be random.

I was watching a YT vid from DBWS showing some newish radar and Lidar sensors that might be useful too. Remember, the mag door switch only tells me the door opened, is still open and closed. It can't tell me about movement in or near the opening. I want all the above and am very comfortable with that kind of coding.

I'd say you should play about a bit with the radar sensors first. I tested some in my home figuring on turning on the workbench lighting automatically when I entered the room and off when I left. It sounded good in theory, but I found that the sensor was detecting my movements in both adjacent rooms and the hallway. It was too sensitive for my purposes.

@will YES, the RCWL-0516 I figured will 'see' right through my hatch. Bill has a YT vid showing some other kinds and one of them may be better. I wasn't concentrating on the vid, I was doing something else or three at the time, but if you approach it from an analogue point of view then it looks more doable. What I mean is determine by test what a human 'looks' like in returned values and just look for values in that range. I will have to experiment, but I think a PIR device or similar might also be worth looking at. That is what they use for inside the house security systems. Of course moving at a snails pace or wearing a mylar suit can defeat them though, ask me how I know LOL.