Really universal soldering controller

Topic: Really universal soldering controller (Read 1047168 times) previous topic - next topic

Re: Really universal soldering controller

Reply #465 – April 28, 2016, 11:37:22 pm

[quote author="sparkybg"]Where exactly is "behind the bridge"? [/quote]

Hi,

directly behind the bridge, lets say at the TVS1-Diode.

If I have 230V AC I get 26V TrueRms after the transformer (without load) that are about 73V AC PkPk Sinus. After the rectifier I get round 36V (half sinus with 100Hz)

If there are 10 % over voltage (253V) it reads 29V after the transformer, 79V PkPk and 39V (100Hz)

Quote

so the voltage there should be half sinusoide with 5V plateau.

In the moment I do not know, what you mean with 5V Plateau?

Re: Really universal soldering controller

Reply #466 – April 28, 2016, 11:38:24 pm

[quote author="MadBekon"]I used OLED from aliexpress.
Works just fine. Good brightness and contrast. 4 USD.
Just too small.
2 inch would be nicer.[/quote]
http://https://www.youtube.com/watch?v=maHOO12lgTg

Re: Really universal soldering controller

Reply #467 – April 28, 2016, 11:41:25 pm

[quote author="Iwanushka"]
I've bought this one http://www.ebay.com/itm/0-96-I2C-IIC-SP ... Swv0tVeD0N
[/quote]

It will be OK. Univision display with SSD1306 has SPI for sure.

Re: Really universal soldering controller

Reply #468 – April 28, 2016, 11:44:55 pm

I measured this values at the Indel transformer 2x12V 150VA and it is possible to send photos.

Re: Really universal soldering controller

Reply #469 – April 28, 2016, 11:51:42 pm

[quote author="overheater"]
Hi,
directly behind the bridge, lets say at the TVS1-Diode.
If I have 230V AC I get 26V TrueRms after the transformer (without load) that are about 73V AC PkPk Sinus. After the rectifier I get round 36V (half sinus with 100Hz)
If there are 10 % over voltage (253V) it reads 29V after the transformer, 79V PkPk and 39V (100Hz)
[/quote]
It should be like that. Again - there is not a filter capacitor behind the bridge, so you must have half sinus there.

[quote author="overheater"]
In the moment I do not know, what you mean with 5V Plateau?[/quote]

Excise my english. There should be around 5V valley, not plateau.

It should be more or less like this, without load on the controller - just the valley should be a bit higher:
[attachment=0]

From what you wrote, your PCB looks OK in this respect.

Re: Really universal soldering controller

Reply #470 – April 28, 2016, 11:57:59 pm

Ok - thank you. But when we get a max. voltage about 40 Volts here, why 75 volts for the FET?

Re: Really universal soldering controller

Reply #471 – April 29, 2016, 12:31:22 am

[quote author="overheater"]Ok - thank you. But when we get a max. voltage about 40 Volts here, why 75 volts for the FET?[/quote]

Because 24V nominal means 34V peak. When transformer has no load on it, it can easily go up to 10% and even more, so it becomes 37. Now, put another 20% for mains variations, and you get 45V. Put some possible peaks here and there, and you get 50 volts. The TVS is 60V, and the transistors are 75 - you have to have some safety margin.

Re: Really universal soldering controller

Reply #472 – April 29, 2016, 02:59:48 am

Ok Sparky,

thank you for your patience!

Quote

you have to have some safety margin.

Re: Really universal soldering controller

Reply #473 – April 29, 2016, 11:51:29 am

[quote author="overheater"]Ok Sparky,

thank you for your patience!

Quote

you have to have some safety margin.

It's good to know that this is the reason......and not some other technical causes I didn't understand.

The only problem is, to order two single Fets from Mouser, Farnell, etc. I have a order for Reichelt - thats the reason, I ask for the two Fets in the beginning. But it seems that they don't have anything with higher voltages in the needed package.[/quote]

TME has AUIRFR3607, IPD12CN10NGATMA1. Shipping to Bulgaria is 7EUR, no matter what the price of the order is.

Don't you have another distributor? I also like buying pars from a local one, but they rarely have everything I need in my projects. I also have local representatives of Farnell, Mouser, Digikey. It is a matter of one week to order anything from these. In Deutchland must be even easier I think.

Re: Really universal soldering controller

Reply #474 – April 29, 2016, 07:06:03 pm

Sparkybg,

Which TVS you would recommend? Had a few 1.5KE68A so used them, but maybe better to use 1.5KE62A or 1.5KE56A

http://lt.farnell.com/webapp/wcs/stores ... reId=10167

http://lt.farnell.com/stmicroelectronic ... dp/9801162

http://lt.farnell.com/stmicroelectronic ... dp/9885099

Re: Really universal soldering controller

Reply #475 – April 29, 2016, 07:26:01 pm

If your MOSFETs are 80V, any of these is OK. However, I would use 62 or 56.

Re: Really universal soldering controller

Reply #476 – April 29, 2016, 07:43:35 pm

[quote author="sparkybg"]If your MOSFETs are 80V, any of these is OK. However, I would use 62 or 56.[/quote]

I think FETs are 75V, at the moment plan is to run it from LAB psu until I get cores to make transformer for it.

Re: Really universal soldering controller

Reply #477 – April 30, 2016, 02:03:27 pm

[quote author="sparkybg"][quote author="dumitruv"]I used LM2674-3.3V instead of LM2675 with 220uH and it works well. I just found it in my monkey box and I decided to give it a try and it seem to work well.

Sparky,
Is there a reason behind using a 1A IC instead of a 500mA one? It is 2$ cheaper.[/quote]

I didn't had an estimate of the final current consumption, so I decided to use 1A version. And it gets a little warm after a hour or so. So I suspect the 0.5A version will get a bit warmer. I don't like a warm parts on my devices. If you look at the power mosfets and the shunt resistor, they are pretty overspecified also. In fact the warmest parts are the rectifier diodes when there's a heavy load on C245 tips. Maybe around 50-55 degrees Celsius. But his happens when I submerge the tip in a pot of cold isopropyl alcohol. This measn full 140 watts for 10 seconds or so...

...and I bought these from a local distributor. 2674 is 1.74USD and 2675 is 2.14USD, so the difference here is only 0.4USD, and if I buy 5pcs, the difference becomes 0.3USD.

Moreover, on farnell's site 2675 is 2.86EUR and 2674 is 3.29EUR - the 1A part is cheaper than 0.5A part.

So it seems it is a reseller-dependant issue.[/quote]

AT Digikey 2674 is CAD 4.12 vs CAD 6.1 2675 ( 2.95 vs 4.37 in USD). What a rip-off...2 X compared to your local distributor...plus 13% tax. I wonder what mark-up these guys have. And I bet your distributor makes profit too. Some times I wonder if this is sucker's land.

Anyway, I measured the current on 3.3V and it is around 90 to 93mA. And 2674 is as cold as a dead raccoon after 10 min.

Re: Really universal soldering controller

Reply #478 – April 30, 2016, 02:09:49 pm

Measure it after you put all the parts together. The display itself consumes more than 93mA. My 2675 gets a little warm after some time. Maybe around 40 degrees Celsius.

Re: Really universal soldering controller

Reply #479 – April 30, 2016, 03:56:26 pm

[quote author="sparkybg"]Measure it after you put all the parts together. The display itself consumes more than 93mA. My 2675 gets a little warm after some time. Maybe around 40 degrees Celsius.[/quote]

I did, I measured in the wire between back and front board with a T15 at 300C.