[quote author="sparkybg"][quote author="Iwanushka"]not that cheap stuffш[/quote] SR580 costs around 0.10USD here. It is cheap indeed. :) [/quote]
Insane price, farnell wants like 75 euro cent +VAT, mouser wants 50 euro cent + VAT for each, so if we compare 1N4 crap that I can get locally for like 5 euro cents, schottky diodes are expensive :)
[quote author="sparkybg"][quote author="Iwanushka"]not that cheap stuffш[/quote] SR580 costs around 0.10USD here. It is cheap indeed. :)
[quote author="Iwanushka"] , I will be replacing schottky bridge with a FET bridge a.k.a ideal diodes to decrease power dissipation.[/quote]
It will give you next to nothing. The controller is limited to 6A RMS. When soldering, the diodes stays cool (under 40 degrees). Only when peak power from the iron is needed, and the iron is over 100W, they become a little warm.
Moreover, the voltage after the bridge must have a valley around 5V - there is a circuit for this in the back PCB. Using MOSFET-s may produce some problems there.[/quote]
sparkybg,
My plan is to change this project a bit, so I can have 2 separate outputs @ max power, in this case FETs will come in handy, I don't like wasting power...
[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... [/quote]
for this power diodes are bad, but at least you are using schottky diodes, not that cheap stuff, I will be replacing schottky bridge with a FET bridge a.k.a ideal diodes to decrease power dissipation.
[quote author="MadBekon"]Hi, I also received my boards and started assembling. After assmbling Back boards, and powering on I got 5V. After replacing divider to 3K and 1.8K i got 3.23V. Is it enough for PIC?
Maybe it would be worth mentioning that in first post, update schematic and BOM.[/quote]
replace R4 1.5k resistor with 2.7k, leave R3 as in BOM 4.7k and you will get 3.313V
I've assembled back board, checked output voltages and saw something strange:Note input voltage is +24VDC 1) -0.6V output stays at -0.34V, 2) +12V output stays at +14-14.2V, EDIT: LTSpice simulation shows +14.58V output, so maybe everything is okay with this one.
Any ideas what could be wrong? power consumption looks okay, PSU says 10mA so for sure it's less than 20mA, there was no current spikes on turn-on nor any magic smoke escaped.
Can you shed some light on what parts are not needed when using OLED, so far I've got this
1. U9 - ULN2003L is not needed, instead Ja-Jg jumpers or 0r resistors must be instslled. 2. Ra-Rg for LED is 47R, for OLED should be jumper or 0R resistors 3. What about Q14, Q15, Q16, Q17 which ones are needed? 4. Are there any other parts that are not needed for OLED?
Also maybe you can share altium files (most important pcb project) it would save lots of time troubleshooting with altium pcb viewer vs using gerber viewer.
You can check mouser europe (if your order is above 50e before tax shipping is free, there are no customs to pay too), in Eu you can also try ELFA/distrelec
[quote author="HeaveNAkirA"]yes i meant to say at the same time (not the same brand - let say hakko - weller, hakko - jbc , jbc - weller), same temps are not a problem i need it for same cheap pens with other type of tips, i don't want to change the tips too often
p.s and i read the thread[/quote]
I stand to be corrected, but you can only use two identical heaters which will be set to the same temp.
can this digital pot MCP4651-503E/ST be replaced with something else? Non of the europe distributors stock it, only digikey has it, but shipping is 60usd for 1$ part, plus all the import taxes/customs paper work will be another 40+euro..
I've placed order for some PCBs and will have around 7 spare sets, they should be with me (in EU) in a month or something like that (depends how fast is snail mail).
