PCB with repetitive design

Solder is many times thicker, and soldering along tracks has been a standard production method to increase ampacity widely used for decades.

NT

Reply to
meow2222
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ce of 1

= 3.1

of

;)

imate how much current it can handle. Perhaps 5A?

places. You can also solder along the tracks.

ard production method to increase ampacity widely used for decades.

Compiling and synthesizing are not very different. You need to specify a a rea, behavior, conditions, and criteria for repetition. Whether you write it in XML with "" or Pascal doesn't m ake a difference. But then drawing the reflection vector for bus "corners" , as above, would also specify a "for" loop.

There is also a constraint specific to the "many small" example. The pathw ays between N units only occur N-1 times. We also might use "mux groups", sequences of "And"s /of/ unique sequences of "Not"s.

Can you get the datasheets in XML from the IC manufacturers? You'd also ne ed the output current and voltage as a function of the inputs.

If you're going to optimize any with the software, it would also be nice to view the transition. Pinouts are constraints on the optimization, but the n that's flexible if you go to silicon.

There might be a voltage spike when I do the commit, but I could just take longer instead and the device could still be faster.

Reply to
Aaron Brady

A niche for IMS once again?

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50mOhm of RDS_on is not a particularly low value for the FETs available today...

Best regards, Piotr

Reply to
Piotr Wyderski

Den torsdag den 14. august 2014 07.05.21 UTC+2 skrev snipped-for-privacy@gmail.com:

you could easily find mosfets 10x better than that for that voltage

and what on earth did you use to draw that "PCB" mspaint?

-Lasse

Reply to
Lasse Langwadt Christensen

There are two traces across the bottom of the MOSFETs on the top of the board. The placement and layout are restricted by the PCB size constraint. It's already 60mm x 60mm. Perhaps a little bigger, but not much more.

Reply to
edward.ming.lee

50 mOhms worst case situation.

It's just a screen capture of the gerber file view.

Reply to
edward.ming.lee

Well even if a part has a funny pinout, you can still reroute the nets.

Reply to
Aaron Brady

Den torsdag den 14. august 2014 15.52.33 UTC+2 skrev snipped-for-privacy@gmail.com:

what MOSFETs are you using? 6x to220 is more than 60mm and thats with the tabs touching

-Lasse

Reply to
Lasse Langwadt Christensen

Top trace:

  1. You can extend it out at each end to give a little more heatsinking, and thus ampacity
  2. You can extend it upward in 4 places to reduce R of a portion of the track
  3. You can add vias to parallel 4 short bits of track on the other (blue) board side, again reducing R and increasing surface area

Lower trace:

  1. You can extend it out at each end to give a little more heatsinking, and thus ampacity
  2. You can extend it upward in 4 places to reduce R of a portion of the track
  3. You can slightly increase the copper area around 2 sides of the 3 pads of its upper section
  4. You can spread out a good percentage of its wiggly descent section.
  5. You can add vias to parallel 7 short bits of track on the other (blue) board side

There's also of course the option to shift some of the stuff down a fraction to enable fatter tracks up top.

NT

Reply to
meow2222

You can also add insulated wire topside or bare wire underside.

NT

Reply to
meow2222

#2,4,6 mounted on top and #1,3,5 reverse mounted on bottom of the PCB. Or perhaps just wire them to externally mounted heat sink. We don't really want the MOSFETs adding to the PCB thermo problem.

Reply to
edward.ming.lee

Den torsdag den 14. august 2014 16.49.37 UTC+2 skrev snipped-for-privacy@gmail.com:

but why all the hassle? it's not a problem routing 3 gate drivers and 6 fets with plenty wide tracks

I'll draw it up later

-Lasse

Reply to
Lasse Langwadt Christensen

1
3.1

That was computed for 2 oz copper.

?-)

Reply to
josephkk

There are only 4 distinct structures repeated several times. Am I correct in assuming I need a list of parts and coordinates? The repetition is sli ghtly imperfect. Units have unique tests for sequential binary (not unary) addressing.

probably cheap DRAM. Are there any special voltage or current requirement s?

Please use a good CAD tool as Eagle for creating the multilayer PCBs. The exact pin voltages and signal voltage levels can be obtained from the IC datasheets.

Reply to
dakupoto

It is strange to see a digital circuit handling such huge currents, that are the domain of high-end power supplies. Given the width and thickness of the traces, the power dissipation/waste due to I^2R heating losses will cook the circuit and the ICs in a short time. Please re-check/re-design your circuit. Remember Intel's Itanioum ?

Reply to
dakupoto

IIRC, about 1A/mm on 2oz. copper, at least for surface traces (internal traces have to be derated from that). On one of my boards, I have 32 5A traces. IIRC, they're 5mm traces.

Sounds like overkill, though perhaps they didn't have enough planes or couldn't afford the surface space for the traces. It's hard to know all of the design constraints just looking at a board. The Idd of the processor I last worked on was ~100A. That was handled on planes though there is no pretending the power system was trivial.

Reply to
krw

nits, probably cheap DRAM. Are there any special voltage or current requir ements?

opper handle? We need over 10A.

To reiterate, to the end of maintaining a general awareness of the goal, am I correct in that the end result is just like a SVG file for the copper? I couldn't find how to specify repetition in the EDA tool I tried. SVG: sc alable vector graphics. I suppose the "parts" aren't necessarily on the li st. Do you just dip the board in a 1/8" puddle of warm solder at the end?

Reply to
Aaron Brady

Most of the IC (MOSFET) can handle over 10A, but we still want to keep the power low.

Here are my 5 top choices:

http://173.224.223.62/motor/fet.php

#3 (FDPN150N10) is the best at 1.5W. However, the input capacitance goes up and switching bandwidth (invert of sum of start/stop/rise/fall time) goes down.

Reply to
edward.ming.lee

Why are you concerned with what the file looks like? It's called a "Gerber" file, and yes, I believe it is an SVG.

Low end tools likely don't have repletion built-in. If your schematic capture tool has hierarchy, the back end tool likely supports repletion (though the reverse is not true).

I guess I don't understand your questions above.

For through-hole parts this is essentially the process. Rather than being a "puddle" it's a puddle with a fountain or wave in the middle (hence "wave soldering").

Current SMT technology uses a "solder paste" that's spread on the board through a metal mask to leave the goo on the solder pads. Parts are then placed on the goo covered pads. After all of the parts are placed the board is put in essentially an oven and the solder paste melts. When it's all cooled, the parts are left soldered to the board.

Reply to
krw

It's vector graphics like SVG but scaling it would probably not be useful.

The only one I've used required me to copy and paste to get duplication. if you set the grid step to the repetition interval it's easy to drop the copies in where needed.

There is a way to do that, but I've never tried. also the drill list for the holes is in a different format to the data for the copper.

One method of mass manufacture is called wave soldering and it's a bit like that. The main other method is reflow. Protoypes are often soldered by hand.

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umop apisdn 


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Jasen Betts

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