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Messages - minkok

2
Project logs / Re: Really universal soldering controller
Hey all!

I'm currently stuck and could use some help figuring out this firmware uploading. I'm using a PICKit3, the latest version of the Firmware published on github, Ver. 5.5 of the MPLab IPE. I'm able to connect to my PICKit fine, but when I try to connect to the PIC32 on the board, I receive this error:

' Currently loaded firmware on PICkit 3
' Firmware Suite Version.....01.56.09
' Firmware type..............PIC32MX
' Too much current has been drawn on VDD. Please disconnect your circuit, check the CLK and DATA lines for shorts and then reconnect.
' Programmer to target power is enabled - VDD = 3.250000 volts.
' Too much current has been drawn on VDD. Please disconnect your circuit, check the CLK and DATA lines for shorts and then reconnect.
' Unable to connect to the target device.
' Failed to get Device ID

I've tried to verify where I can that there's no shorts or cold solder joints, but without the board I'm sure theres parts I missed. Any help would be very appreciated!
Supply MCU from backboard with 3.3v or with an external power source. Do not use ( disconnect ) power supply pin from PICKIT to the front board (do not power front board from PICkit)
3
Project logs / Re: Really universal soldering controller
I was think about the scenario when the main supply is toroid transformer while aux supply is SMPS.
Why you do speak for that at all, In electronics ( physics ) there is a concept for the potential difference and if you connect ( root them together ) the negative wires of two ( many ) different sources they will share the same circuit, potential differences, and will bring their ​own noises to the shared network
5
Project logs / Re: Really universal soldering controller
For the driver? It doesn't really matter as long as the driver output voltage is enough to fully open the MOSFETs (and not exceed maximum driver supply, obviously).
Zeners left there to act as suppressors to protect the driver and the converter.
It's not about the price. Fewer parts mean less hassle to put it all together, less space required. If it would reduce the BOM, even better.
Everybody bears their own responsibility for what is made on his board. I just can claim - that way is not the proper one to do it. The original design is much, much better and you can keep it without changes, compared to that, or recalculate the current to correspond to the lower voltage.
6
Project logs / Re: Really universal soldering controller
Those parts are required for a higher voltage input and it's a robust design. If input is limited to nominal 12V, they can be dropped to simplify the power stage.
Nominal quiescent current of TC4428 with 3V input - 4.5mA, which means voltage drop of around 1.5V on R20. When nominal input voltage is 24V, it's not a big deal, but with the input voltage of 12V this is significant drop. Though, it's proved to be working fine on 12V supplies in C210 configurations. 330 Ohms is really huge resistance for that application and it's not limiting driver current, since it is directly provided by C19. I believe it's there for decoupling.
What about voltage jump - 2-3 times, do you think its regulation is enough by simple zener and at the same time to supply properly needed current not only to the driver but also to other devices may be added later ( isn't that the purpose of the change ),  everything that, on the price of cents for extra linear stabilization - simple and cheap
7
Project logs / Re: Really universal soldering controller
If aux supply is 10~15VDC, Q13 also can be removed and bridged, D14 removed and bridged, R19 removed. R20 has a rather large resistance, something like 22~47 Ohms would be enough to suppress driver noise.
When making changes, Please make them correct, do not modify that Schematic to cheap design ( profit purposed or economy ), If you want changes - replace it with something other.
R20 - current limiting for mosfet drv, regulate power dissipation of Q13
10
Project logs / Re: Really universal soldering controller
I am planning to do a revamp of Unisolder using STM32 instead of PIC32 and will be all modular design (i.e. you can swap in different power board for different applications while keeping the MCU board).
All of us have ideas and want them to become real. I can only advise you to count well the pros and cons. Definitely, it will be not short and easy and will involve resources
11
Project logs / Re: Really universal soldering controller
Modular Power boards isn't for hot-swapping in my opinion. It is more about Balance between budget and performance needed. (You don't need big expensive 100v+ low Rdson MOSFETs for 210 and 105 handles) Another aspect of modular design is that iron Configuration and Firmware should be separated so that Iron Profiled can be easily trimmed or added to the station, besides MCU board could support up to 2 or even 4 independent heating channels, but you can just install one heating channel.
I don't want to be critical, but that sounds a bit strange. Let say we have a modular design that consists of a certain count of modules , if you want to separate them for using the low parameters transistors you should use modular power supply boards also (cheap transistors/low voltage power supply ) In that case You could assemble 2 -3 independent soldering stations from your modules. What about the Trf. - it has to support all needed voltages and enough power to support 4 independent tools? Or I have to collect 4 of them?
Isn't that the advantage of Unisolder, on 1 instrument to play many tools and if there is switching board attached to it, to connect them all  the same time and use them 1 by 1
12
Project logs / Re: Really universal soldering controller
I totally agrees with you afedorov regarding the auxiliary 12v supply. Unfortunately, per Sparkybg's current design, you have to keep the valley fill circuit near Q1 in order to minimize switching noise around zero crossing. I am planning to do a revamp of Unisolder using STM32 instead of PIC32 and will be all modular design (i.e. you can swap in different power board for different applications while keeping the MCU board).
Modular design - good approach, No cables - easy assemble, less noise, place saving, about swapping power boards - big effort ( open the case and so on ). For me, I am impatient even when I need to change the handle! I want just to grab it and to use it
13
Project logs / Re: Really universal soldering controller
admaverick, minkok, it's much easier to just implement auxiliary DC supply, rather than messing with values and dropping 30-odd Volts on Q1.
If I was going to redesign the power board to support higher voltage irons, I'd use 12V supply and get rid of Q1 and Q13 circuits all along.
It could be a separate 3W AC-DC supply, like IRM-03-12 or separate 9VAC transformer winding with it's own rectifier and filtering. If you have a toroidal transformer, just wind a turn on top and measure the voltage on it, then wind the remaining.
I agree with you. It will be much more stable, more power for 12V extra devices added later, but will create more noise ( for converter use ) and needs more place ( extra board, cables), while sparky's sch still support that. Actually, it depends only on the guy who needs that