Power switch recommendation

[wink]

[mypasswordis]

Pls keep your spamming to HF thx

[luvdunhill]

An all in one would be nice, with some sort of PCB mounted xfmr. Seems like the EI-30 types that Amb spec'd are harder to find these days.


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I am about ready to tackle this one. Would you be up for collaborating on this?

[Pars]

Sure, I'd be up for that.

[mypasswordis]

Interested to see what you guys come up with! The one I designed ended up being too big still (my PCB width hack didn't work ), so I'm going to use the Mean Well ac/dc module like in the Dynalo mini. Even the Mean Well version barely fits.

 

[Pars]

What 3D package are you doing those in Justin?

I was messing around trying to figure out how to do voltage switching with 2 transformers, 1 using a relay to switch on (ala Amb e24), but handling voltage switching for 120/240. Does the below schematic look feasible?

 

[mypasswordis]

Still using Kicad and its 3d libraries, haven't had time to look into Eagle again. 

Maybe I don't know how to read that schematic or maybe it's in a separate sheet but I am not seeing any relay drivers or 12V supply. The operation of the e24 seems to be a bit different as that is using a low voltage switch to turn on high voltage relays for line AC. The V&K voltage selector unit is already a line voltage switch and can handle 250VAC at (?) 5A, so however you would connect it to one transformer's primaries, just put the second one in parallel.

Edited February 13, 2018 by mypasswordis

[Pars]

None of that shit is in yet, i was just messing around with doing the voltage switch and having AC relays in for the main transformer. I think I basically did just parallel the 2nd set of primaries with the first, with the relays after that. I realize that when switched to 240V both relay contacts are in series but as far as I could see, that is the only way to do it. Of course I could cheat and use something like a MeanWell for the relay/e24 thingie...

[luvdunhill]

Done some work on this. I've come to the conclusion to do the logic I'd like, I really need a microcontroller. So, going to start from scratch with that assumption. Sigh.

[luvdunhill]

So, general features I am after are:

Momentary switch operation
Remote trigger input
Support for more than one temperature sensor (not thermal breakers)
Antiparallel bi-color LED indication
Support for AC-DC switcher and AC transformer footprints
High current relay control (mechanical and SSR, though I am done with SSRs)

Probably three PCBs - transformer, control and relay.

Other requests? Maybe IR control?

[luvdunhill]

ok, here's a generic auxiliary power supply. what does anyone think? any additional features you would like? 

 

[Pars]

That looks pretty good Marc. Is your intent to support all 3 on a single board (single, dual and the LP2992)?

[luvdunhill]

That looks pretty good Marc. Is your intent to support all 3 on a single board (single, dual and the LP2992)?

 

Exactly. I worked carefully with the do not allow traces regions on the switchers and they will work just fine and it turns out to be a useful little board.

 

I think I need to mirror V1 (MOV suggested for 220V operation), add an mains input label, and change the 5V output label to Vr (in case a 3.3V regulator or other fixed output regulator that works with low ESR caps, such as the LP2992, is used). A little bit more copper for the regulator would be nice as heat is dissipates through its pins. Also need to add polarity makers to the caps - I didn’t have this size in my library, oddly enough.

 

I will make the changes this afternoon and order 3 and make them up. I need to double check that the 20A relay I am eyeing will fit on the same dimensioned board. The other parts are all SMD, including the micro controller so they will fit in a square inch top and bottom.

 

 

[luvdunhill]

Ok, three on the way. Next up is the control board!

[luvdunhill]

Ok, three on the way. Next up is the control board!

Power supply boards showed up!

I haven’t placed the order for the AC/DC modules, but had these EI transformers around and they fit just fine.

[luvdunhill]

Ok, here's the schematic for the control board. A few questions:

1.) I've never used a MOSFET pull-up in the manner described on the 1-Wire circuit. Does this look correct? I figured I might want a dozen or so external temperature sensors, so I wanted to beef this up

2.) In general, am I using the "right" uC pins? I tended to randomly assign them, but I know that there are specific pins suited for different things (ADC, D, UART, etc.). A pair of eyes on this would be great.

3.) I'd like to use this bootloader, https://github.com/micronucleus/micronucleus. Any reason to think this wouldn't be compatible? It looks like it might need an external crystal, I have that.

4.) Eyes on the MOSFET relay driver? I wanted to be able to drive high current things like SSRs, etc.

5.) Other features? Better name?

[luvdunhill]

Getting this on a two layer board the same size as the PS will be fun.

Any suggestions on a crystal that is smaller and perhaps doesn’t need external components?

Smaller opto isolator recommendation? Don’t need anything fancy will just accept DC voltage for the trigger input.

[luvdunhill]

Well, I have some space left on the board!

I am seriously considering adding one of these to the bottom:

https://datasheets.maximintegrated.com/en/ds/MAX11301.pdf

I think I can keep it all 2-layer as well

[Kerry]

I've used this crystal with built in capacitance (Q1): CSTCE16MOV

[luvdunhill]

Thanks Kerry! If anyone is following along at home, here's the Atmel version of this part - CSTCE8M00G52-R0. It is NRND though

[Pars]

Looks like Mouser has some Abracon that have the built in cap. And yes, all of the Murata ones they stock appear to be EOL.

[luvdunhill]

More re-working the schematic, mostly around the USB input. The wrinkle is the 4DSystems OLED displays want 5V and I need 3.3V for USB compliance, while still supporting higher voltage relays. It should be a pretty flexible board when I am done. Now the main issue is dealing with the oh so large 0805 caps in high density trace regions. I see why Kerry used small caps (0603?) right around the uC in his photo above!