Velleman K7200 Gerber file

[Wizpic]

This is my take on the all in one PCB, I want to be able to send them off to a PCB house and want to make sure everything is there or not need to be there before I send them off.

Hopefully it will look like what's in the pic with dome bare tracks to put extra solder to help carry the current.

So if someone could check and verify for me 

[optikon]

I checked it in a CAM tool

I did some basic DFM on it. I think it looks ok, but have some notes below

Notes
1) Min space found ~15 mil - no concern
2) Min trace found = 5 mil - (Check with Vendor, some charge extra for below 6 mil) looks easy to fix.
3) Smallest hole 28 mil - no concern
4) Top and bottom paste layers are empty except for a border outline which doesn't make sense. I can see this is a through hole design so I assume you will not be sending paste layers to vendor. In this case, no issue just that I am not sure of your intention. I would leave out GTP & GBP

Which Vendor will you take this to? We can look at their design rules . .

[Wizpic]

Thanks for taking a look, I don't normally use through hole always SMT but as I could not find the SMT version of the LM723 I decided to stick with through hole.

Hopefully the pink and orange tracks in your pic should mean they will show the bare track with no green mask on them so I can add extra solder.

I've checked with the manufacture  specs as it's from a company in China of Ebay.

There spec is Min. Line Width:3mil, Min. Line Spacing:3mil so I guess this meets there spec.

I have looked at the JLC PCB service seems reasonable price and seen many people mention them in there videos.
I cold up-load the complete altium files if need be or any one is interested in it

Wizpic

[optikon]

Thanks for taking a look, I don't normally use through hole always SMT but as I could not find the SMT version of the LM723 I decided to stick with through hole.

Hopefully the pink and orange tracks in your pic should mean they will show the bare track with no green mask on them so I can add extra solder.

I've checked with the manufacture  specs as it's from a company in China of Ebay.

There spec is Min. Line Width:3mil, Min. Line Spacing:3mil so I guess this meets there spec.

I have looked at the JLC PCB service seems reasonable price and seen many people mention them in there videos.
I cold up-load the complete altium files if need be or any one is interested in it

Wizpic

The 3 mil spec though is at the limit of their capability and those who use it will pay BIG $$$ for that. Generally, the China places will tell you where that transition is from cheap to added price. Even though they could do 5 mil, do you want to pay more if 6 mil was a lot cheaper?

You should find out - its not about their max capability, its about where that low cost price ends.

[Sideshow Bob]

What will be the correct thread for the schematics used for this PCB

[Wizpic]

Slideshow Bob,
I will upload the Altium files or if you prefer I can convert to pdf and upload here.

[Sideshow Bob]

Slideshow Bob,
I will upload the Altium files or if you prefer I can convert to pdf and upload here.

If you can do one or both it would be appreciated.

[Wizpic]

If you can do one or both it would be appreciated.

Here you go, The complete project and files

[sphinx]

I dloaded your fles and i was wondering, should planes go right to the edge. Will that not cause any issues when they cut the boards with eventual shorts ?

[Wizpic]

Because I’m so used to doing that, because I use my CNC machine to make the one off boards and but the outside edge. I’d thought I’d have these boards made to make them look nice.

I will add a keep out layer around the edge and rebuild the polygons as I’m still tweaking and playing around with it, has I. In no rush.

I’ve now removed the other 2 layers that are not needed.

[sphinx]

just curious are lm723 and ua723 the same ic. if they are same then it looks like they are still available ju looked at mouser and alot cheaper

[sadman]

just curious are lm723 and ua723 the same ic. if they are same then it looks like they are still available ju looked at mouser and alot cheaper

yes both are same ua723 made by Texas instrument have lot of improvement (like internal voltage ref is temp compensated)  to old variant LM723 data sheet can be found on Texas instrument web page they have also added LDO capabilities in 2018 so it is much better then the LM723 and good news is that it will continue in there production line.

sadman

[Wizpic]

Just an little update on project, I've had the boards made and they look good quality only took less than 5 days to arrive from the date of the order.

I've built one board up and been testing it from a 24V PSU, A long the way there was on little error with one transistor foot print was incorrect, Which I checked and checked but this one must have slipped through the net. We live and learn. Not that it was to much trouble I just turned it around.

I've also be working on the front end on the digital part. I've attached a couple of photo's just to show if anyone is interested in following.

The code is almost completed, Just awaiting some more DAC's to arrive as I've only one at the moment but I can use this to get the voltage control working then swap to the current control. I've done it so that you cna use both pots and keypad to set the output voltage and current.

Brief description on how it work,
It use a 16way key pad to set the voltage on Channel 1 you press the * key once, Press it again and you move to channel 2 and a third press it aborts the input but outputs remain the same, This is the same for current but press # instead.
Once you have selected the channel, The voltage reading starts to flash then you can enter the voltage required and you can see the keypress your entering, once set this displays the set voltage along with the set current at the bottom as you can see.

I've got to work out the math's so when you enter 5.00v on the keypad the output voltage is matched the same.(this is on my working list).

Both channels will be isolated from each other and I shall be using    an SI8600 Chip(I2C isolator )so that I can use one display and controller for both.

More will follow soon and including a video of the digital part working.

[Old_but_Alive]

I love rotary encoders for this type of application, if you choose the ones with  a press switch built in, then its easy to move between modes.

A good design though, and thanks for sharing

[metal]

I agree with old_but_Alive, rotary encoder is much better than keypads for similar apps.

[Wizpic]

The rotary encoder may be the way to go as at the moment I’m having a nightmare trying to get the correct values to set the output voltage and do away with the pots and key pad, this way I may be able to use an existing power supply case I got 

[Sideshow Bob]

The rotary encoder may be the way to go as at the moment I’m having a nightmare trying to get the correct values to set the output voltage and do away with the pots and key pad, this way I may be able to use an existing power supply case I got 

What will be your DAC choice for this build

[Old_but_Alive]

I like the mcrochip I2C chips, very easy to use

MCP4728  Quad 12 bit - I have used this before, lovely device

MCP47CMB22  Dual 12bit

internal ref, whats not to like

[Wizpic]

At the moment it’s an MCP4725 which I’m just trying but may use an 16bit dac but this depends if the 12bit dac does satisfactory, I think it’s just to the way I’m entering the keypad value, I will see if I can get to the bottom of it once I get a bit more time as it was late last night

[Sideshow Bob]

At the moment it’s an MCP4725 which I’m just trying but may use an 16bit dac but this depends if the 12bit dac does satisfactory, I think it’s just to the way I’m entering the keypad value, I will see if I can get to the bottom of it once I get a bit more time as it was late last night

Nah I do not think you need 16 bit. Whit a resolution of say 0.05 volt you will need 480 steps in the 0-24 volt range. A 0.01 resolution will require 2400 steps. I would say going lower than 0.01 volt would not be very practical nor needed

[metal]

those DAC/ADC chips from microchip are not suitable for such applications. I remember Dave Jones tried to do a similar project which ended a complete *** up few years back. Since then I am always wondering how vendors do it

[Sideshow Bob]

those DAC/ADC chips from microchip are not suitable for such applications. I remember Dave Jones tried to do a similar project which ended a complete *** up few years back. Since then I am always wondering how vendors do it

Do you remember why? Also I am asuming we are talking about the Dave Jones from EEV blog Not the footballer

[Old_but_Alive]

please give some data on the mcrochip products, they worked for me a treat

[sadman]

why not use PWM instead of DAC PWM work fine using capture compare module and you can get easily resolution of 0.05

sadman

[metal]

Do you remember why? Also I am asuming we are talking about the Dave Jones from EEV blog Not the footballer

yea, Dave Jones - the aussie clown - I am not sure if I remember correctly, but it was sth related to the stability of the readings, ppm issues may be, and he said I should have used higher quality/resolution chips to overcome last digit instability and bad resolution. If I remember correctly, he should have used 16-bits stuff, and ignore the last bit to get real good readings. I really wanted that project to work, because I always wanted to do such power supplies, but as we all know, Dave turned out to be an oscilloscope commercial reviewer and a clown

please give some data on the mcrochip products, they worked for me a treat

Since I don't remember much, we have to look the videos up, watch them and then conclude again
Also, if they worked a treat for you, enlighten us please, sure your knowledge will shine here