For discussion of Speeduino compatible boards designed / built by other members of the forum and for guidance around making such a board
By NickZ
#24534
What are your plans for the ignition outputs, i see you are switching to ground, what if you want to run LS coils that use a 5V positive signal to fire?
By dazq
#24539
What connector are you using on this? Please don't say a db37......!

If you aren't going to have more than 4ch on board would you consider adding an expansion socket to allow more channels?????
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By dvjcodec
#24549
Is a good question, because I didn't focus about that. In future I want to run Mercedes M111 engine. I found IRGS14C40L for coils. This IGBT have good price on aliexpress, so I use them. What solution is better, positive or negative? I'm newbie with this questions, so need to learn a lot, but typical, direct coil swithing is a negative, so maybe is a better, cheap solution?

For 1st revision I was thinking about DB37, yes :( I didn't found other 35-40 pins conectors with Eagle's footprint :( I found a lot connectors in China, but havn't drawings to make footprint :(
Last edited by dvjcodec on Tue Apr 03, 2018 2:54 pm, edited 1 time in total.
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By dvjcodec
#24556
Scheme update. 3V3 direct from Teensy 3.5 (max. load up to 250mA) - I think is enough, but add one more regulator is not a problem (LM117 for example). Will try to put all elements to 100x80 double layer board. Most components on the board :)
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speeduino_t3_5_scheme.png
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Last edited by dvjcodec on Tue Apr 03, 2018 2:55 pm, edited 1 time in total.
By noisymime
#24582
So, just to throw an annoying idea out there at this late stage of your design....

With the exception of the MAP sensor, which requires 5v to operate, all the other analog sensor inputs can be run at the 3.3v system voltage. That would mean you can drop the level converters for most of those inputs (MAP being the exception). The only reason I use them on the Teensy adapter board is because it's designed to plug into a 5v board. When you're starting from scratch, you can set everything to operate off the 3v3 rail :)

That said, the setup you've got there will work just fine, it's just more components and traces.
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By PSIG
#24583
100x80mm would be great, as it would allow plenty of room in a standard v0.4 Hammond case for adding a connector board for the user's connector of choice. 8-)
dvjcodec wrote: Sat Feb 24, 2018 6:33 am... What solution is better, positive or negative? I'm newbie with this questions, so need to learn a lot, but typical, direct coil swithing is a negative, so maybe is a better, cheap solution?
I'm not sure I understand your question. Standard coils are almost always fired by grounding the coil (-) through the IGBT. Please look at the Ignition Coil section of the Wiki and try asking again.

David
User avatar
By dvjcodec
#24586
noisymime wrote: Mon Feb 26, 2018 12:58 am The only reason I use them on the Teensy adapter board is because it's designed to plug into a 5v board. When you're starting from scratch, you can set everything to operate off the 3v3 rail :)
I found in datasheet, MPXH6400A minimum supply voltage is 4.64V :( In future I I don't know what kind of sensor be connected to board. 5V for sensors seems be universal. But if only map sensor need 5V and other not, hmmm, need to change :)

About the coils, LS1 is switched via 5V signal, so maybe is better than direct (-12V) switching? TC4424 via IRGB14C40L? Small tracers, lower current?
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By PSIG
#24588
dvjcodec wrote: Mon Feb 26, 2018 6:45 amI found in datasheet, MPXH6400A minimum supply voltage is 4.64V :( In future I I don't know what kind of sensor be connected to board. 5V for sensors seems be universal. But if only map sensor need 5V and other not, hmmm, need to change :)
One consideration to keep 5V signal shifting is to allow piggyback installations on current systems. If only 3V3 except for MAP, then an adapter board would be needed to accept 5V signals from OEM ECMs. Your decision.
dvjcodec wrote: Mon Feb 26, 2018 6:45 amAbout the coils ... TC4424 via IRGB14C40L?
This. It can be used with smart or standard coils, although using internal coil drivers (IRGB14C40L) may bring noise onto the board. Everything is a compromise.

[EDIT] BTW - you are pulling the ENable pin high on the stepper. This will stop all outputs to the stepper motor. High to block, and no connection (internal pulldown) to operate. If using standard Speeduino code, there is an ENable output to prevent stepper hunting when not operating. Tie the ENable pin to this output.

David
By fram
#24590
Hi dvjcodec ,

Keep in mind, IGBT are high current/voltage and noisy components.
So, your PCB will have drain a lot of current running from IGBT signal to ground.

I'm a bit afraid about the placement of these IGBTs, and especially about:
-The size of the IGBT copper traces
-The lenght of the IGBT copper traces
- The trace to trace distance copper (take care of your PCB design rules for high power components)
- The fact you'll cross all the PCB with these traces.

Spending time for a very good components placement is really really important.

My 2 cents ;)
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