EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: TiN on December 16, 2015, 04:48:43 am
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Hi all,
Since DC load topics are often pop up here and there on EEVBlog, let me add some into mixture as well.
I hope fellow volt-nuts would not judge this one too hard, but I decided to open my old ATE design, which I did in 2008 or so. There is no precision better than 1% in this one here :-DMM, but it have 2000W of capacity! 8)
Back then I had part-time job as reviewer on few PC websites, covering PC PSU evaluation and testing. All I had was a cheapie DMM and Tektronix 2246, which is not enough to do proper power supply testing, so I ended up with need of multichannel high-power DC load very quickly. Quick evaluation of market shown that I had no way in hell to get any of those multichannel beasts from Chroma and such with regular student money. Solution? If you can't buy it, make it!
Version 1
(http://fotkidepo.ru/photo/115530/9515ZdJQKBoMHD/173603w.jpg)
Hence the prototype was born, using MOSFET, CPU fansink, and bunch of opamps. I was into learning MCUs and programming them same time, so it was obvious to mix both together and make automatic DC loader/PSU tester. Bunch of MOSFETs in progress were burnt, of course :)
(http://fotkidepo.ru/photo/115530/9515ZdJQKBoMHD/252266w.jpg)
It ended up using IR FB180SA10P ISOTOP-package mosfets (really nice beasts, but expensive), ATMEL ARM7 MCU and multichannel 8bit DAC. No precision stuff, I barely knew anything about analog back then (not that I know a lot now either! :blah:).
That thing worked, but was not so easy to use, as often some wires were getting loose, or some other bugs haunted it.
(http://fotkidepo.ru/photo/115530/9515ZdJQKBoMHD/177520w.jpg)
Version 2
So I redesigned whole thing, and called it Neutron, as it was second iteration (first one was Proton :-DD).
(https://xdevs.com/doc/xDevs.com/Neutron/sch/pcb_top.png)
Nice 4-layer PCB now, with all connector front end and measurement circuitry on same board. The only thing left externally are actual power MOSFETs with their current shunt resistors.
(https://xdevs.com/doc/xDevs.com/Neutron/img/topm_1.jpg)(https://xdevs.com/doc/xDevs.com/Neutron/img/botm_1.jpg) (https://xdevs.com/article/neutron/)
Software was revamped too, with great help by friend of mine, which works as back-end web developer and have no idea about any of embedded stuff ;D
(https://xdevs.com/doc/xDevs.com/Neutron/sw/10a_d.png) (https://xdevs.com/article/neutron/)
As a result, whole thing was making pretty graphs like this one:
(https://xdevs.com/doc/xDevs.com/Neutron/img/enermax1.gif)
All design details, schematics, firmwares, softwares, dozens of photos and files for grabs are available in article on my site (https://xdevs.com/article/neutron/).
Hope you like it :)
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Nice job. If you dont mind me asking, where/who did you review for?
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Russian website mostly, overclockers.ru.
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I seen this long ago, I really liked it, a lot of work. Software was also simple. Kinda wish I had this right now.Good job Tin :clap: