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Universal DRSSTC Driver V2.5 (Sold Out)

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Goodchild

Mon Apr 08 2013, 06:12AM

Registered Member #2292 Joined: Fri Aug 14 2009, 05:33PM
Location: The Wild West AKA Arizona
Posts: 795

Well I figured this is far enough along now that I would share it with you guys. This is a tweaked version of Steve Ward's UD2.1 (I call it the UD2.5). Basically it has all the PCB errors fixed from the UD2.1 and also has some added new features, most suggested by the people in the solid state Tesla coil community.

Probably the biggest add-on is the addition of the IFD95 fiber optic receiver. I know I lot of people use these units and now you can use it with the UD2 with no extra modifications! As an added bonus it also makes any coil compatible with interrupters using fiber of both types. The fiber units have OR operation so you can switch between using one or the other very easily.

As of now, it bench tested successively. I will put it in a DR by next week for test runs. I have high hopes!
I plan to host the board files on my website for anyone to use in the future.

Board files and notes here ->

Here is a list of changes and add-ons:

Fixed PCB error in TL3116 feedback network
Linked schematic and PCB files in eagle
Added support for industrial fiber optics IFD95T or IFD95C fiber RX units
Changed GDT primary damping resistor to larger through hole for better heat dissipation
Chained 5Vreg input to 9Vreg output for better thermal performance in 5Vreg
Rotated all Vregs 90 degrees for easy heatsinking
Added socket system for phase lead inductor for quick swap
Changed phase lead select header to allow for LR or just R burden network (for debugging)
Added optional second parallel burden resistor in OCD network for larger coils
Electrolytic capacitors changed to through hole parts
LED header labels on underside of PCB
PW limiting circuit found in UD2 has been removed
Test points added for easy reading of OCD set point voltage (TP1)

All credit goes to Steven Ward for the original design of the UD2. LONG LIVE THE UD!

8630925598 C01d41545d Z

UPDATE 5/8/13 REV A

Well as I said originally this is a beta board at the moment. Someone pointed out to me in an email that I forgot a pull down resistor from the diode merge junction for the fiber OR operation. I have updated the board files and posted the new files on my website under the original link.

If you have already made one of my board an easy fix can be made by kludging a 1k resistor from the output of the diode junction/AND input to ground to act as a pull down. Check the new schematic for reference (resistor R21). I found it an easy fix using the vias on the board and a 1k through hole resistor.

8992921300 C7a45e3aa5

OK so I decided that I will be selling these boards fully assembled and tested now that I have a working reflow oven. I will be fabbing the UD2.5 Rev B boards price is as follows.

Fully assembled/Tested board -> $125 + Shipping
Board only -> $25 + Shipping

Boards will come by default with both fibers, vReg heat sink, and connectors installed. I can also do variations on this process if you are interested.

Other possible configs:

No connectors
No Fiber
Only SMD soldered
etc...

PM me if you are interested.

UD2.5 Rev B

9721756264 F4d4f93ca1 Z

Kizmo

Mon Apr 08 2013, 08:30AM

Registered Member #599 Joined: Thu Mar 22 2007, 07:40PM
Location: Northern Finland, Rovaniemi
Posts: 624

Looks pretty sweet.

One thing i would like to see in UD2.5 (which is something i modified to my UD1.3 build) is undervoltage shutdown. If 24V rail for gate drive drops below 23Volts, the interrupter line gets disabled with NC small signal relay.

If controller looses power it SHOULD shut down before 5V logic goes crazy or igbt gates wont have enough potential for saturation.

Steve Conner

Mon Apr 08 2013, 10:34AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

I agree so strongly that my drivers had this feature for the past 6 years.

Physics Junkie

Mon Apr 08 2013, 11:29AM

Registered Member #7267 Joined: Tue Oct 16 2012, 12:16AM
Location: Detroit, Michigan
Posts: 407

Cool! I'm looking forward to the board files.

So all the parts are the same with the exception of the added FO and through hole components?

HV Enthusiast

Mon Apr 08 2013, 01:56PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Looks great!
One suggestion on the PCB routing.

When you have segregated ground planes (power /digital) sections, make sure you have a bridge between the planes anytime you have signals going between the two.

Basically, for this, if you have two gate signals coming from your digital side and then going to the power section side, keep them close together crossing the ground break, and then on the ground plane, put a little trace underneath them that connects both ground planes. This keeps the signals tightly coupled together. Otherwise, the return for those signals will go who knows where as it tries to make it back to the source.

EMC Guru Henry Ott overs this extensively in his book which is a must have for any power engineer!

You should definately check out the following book. Its the BIBLE in EMC/EME design and would be a great asset and if you have the opportunity to attend one of Henry Ott's course, definately take it! I have taken it 3 times so far and it probably has been the best engineering class i've ever taken.

Steve Conner

Mon Apr 08 2013, 02:01PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Henry Ott famously published a joke article, "10 ways to maximize emission from your product".

He might have added #11, make your product a Tesla coil!

HV Enthusiast

Mon Apr 08 2013, 02:07PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Steve Conner wrote ...

Henry Ott famously published a joke article, "10 ways to maximize emission from your product".

He might have added #11, make your product a Tesla coil!

I did fire up a coil for him about 10 years ago when he visited for a training session. He just shook is head! lol

Goodchild

Mon Apr 08 2013, 04:04PM

Registered Member #2292 Joined: Fri Aug 14 2009, 05:33PM
Location: The Wild West AKA Arizona
Posts: 795

I like the idea of an UVLO. I will add this to the next revision.

Also EVR the point you made about the ground plane makes sense, however the one thing I worry about is two traces crossing the plane underneath, I see the possibly of a ground loop.

This board is mounting hole and electrically compatible with the UD2 and UD1.3, the fiber is even in the same place. Most of the parts are the same with the exception of the added parts and the parts that got changed to through hole. The board in the photo has a 7mm inductor footprint as well, but I plan to change this back to 10mm.

HV Enthusiast

Mon Apr 08 2013, 04:36PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Yes, thats a concern.

However, you already have a large ground loop with the gate signal. If looking at the board if your gate signals are near the bottom and the bridge between planes at the top of the board, all your return circulating current will have to go all the way to the top of the board and return back down to get back to the source.

Of course, for this application and the low frequency nature of the gate signals, it probably doesn't really matter.

I know a big push by all the EMC experts in the industry is to get rid of split plane designs and go with single plane designs where components are properly segregated. In practice, its easier to control circulating currents with properly segregated boards and than to try creating a split plane configuration where a lot of thought has to go where signals are bridging planes, etc...

But in the end, this is just splitting hairs. We all know this is a solid design and works as is, so i'm just nitpicking. :)

But, definately buy the Henry Ott book if you can. It will help you out greatly as you continue your education and work in power electronics. Its the BIBLE!

teravolt

Tue Apr 09 2013, 07:29PM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

can this board be used for a QCW and has the schematic changed much? when will it be relieced?

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