A new ignition circuit

Absolutelywonderful! Thanks.
Mosey

Looking good would like to build here.
Thanks
Jay

OK. Here is the final circuit. I've tested the heck out of this one, including driving full size coils, simulating the input from high RPMs, low RPMs, multicylinder ignitions, etc.

Higher resolution PDF versions of the schematics below are attached...

John

View attachment Sheet1.pdf

View attachment Sheet2.pdf

Great Sharing I really want to know about this.

Thanks guys great circuit, had some spare time yesterday
and all parts in stock and put it together. works great.
I think with a little bit of tweeking with a double side PCB
it will be the size of a quarterThm:

Thanks guys for all the time and effort put into this ignition. I'm sure there will be many building it, including myself. I have one question. I have tried to find the terminal strips that you show in the video. I have a DigiKey catalog and for the life of me I can't find something like you show. Any info would certainly be appreciated.
gbritnell

gbritnell said:

Thanks guys for all the time and effort put into this ignition. I'm sure there will be many building it, including myself. I have one question. I have tried to find the terminal strips that you show in the video. I have a DigiKey catalog and for the life of me I can't find something like you show. Any info would certainly be appreciated.
gbritnell

Click to expand...

here George

http://www.digikey.com/product-sear...d/1442751?k=PCB 5mm terminal block side entry

gbritnell said:

Thanks guys for all the time and effort put into this ignition. I'm sure there will be many building it, including myself. I have one question. I have tried to find the terminal strips that you show in the video. I have a DigiKey catalog and for the life of me I can't find something like you show. Any info would certainly be appreciated.
gbritnell

Click to expand...

George, It was one of these that I used...

http://www.digikey.com/scripts/dkse...tm=0&fid=0&quantity=0&PV1075=9&PV89=1&stock=1

John

canadianhorsepower said:

Thanks guys great circuit, had some spare time yesterday
and all parts in stock and put it together. works great.
I think with a little bit of tweeking with a double side PCB
it will be the size of a quarterThm:

Click to expand...

Thanks Luc,

I think the size of a quarter is very achieveable. My prototype is roughly 1 x 1". If we we to use SMT components (don't be afraid guys - no smaller than 0805 sizes), we could get it even smaller!

John

jgedde said:

Thanks Luc,

I think the size of a quarter is very achieveable. My prototype is roughly 1 x 1". If we we to use SMT components (don't be afraid guys - no smaller than 0805 sizes), we could get it even smaller!

John

Click to expand...

Hey John your sugesting a heat sink for high RPM you think
that SMT would handle it?:fan:

i didnt understand 0805 sizes

canadianhorsepower said:

Hey John your sugesting a heat sink for high RPM you think
that SMT would handle it?:fan:

i didnt understand 0805 sizes

Click to expand...

The SMT version of the IGBT has a theta jc (thermal resistance from junction to case) similar to the TO-220, so assuming you built a thermal path into the board (or a heatsink plane), it would be fine.

I ran the circuit using an input of 533 Hz (an 8 cylinder engine at 8000 RPM with a dwell angle of about 15-20 deg ), and the transistor ran rather warm with no heatsink. You could likely get away with no heatsink, but in any case only a small heatsink would be needed)

The coil was also very warm showing that a ballast resistor would beneficial in this case!

At 5 Hz (a hit and miss engine at 600 RPM, Q1 and the coil are ice cold)

That said, I'd still use the TO-220 on an SMT board mounted vertically. That would allow the board to be smaller (the SMT version has to lay flat).

As far as 0805 is concerned, that may not be familiar outside the US. I'm presuming you use metric sizes in Canada. In that case, using the metric designation, they're known as 2012 resistors. I usually use the Panasonic ERJ-6ENF series of resistors...

The four digits are a size code. 0805 is 0.08" long by 0.05" wide. That's about the smallest resistor that can be hand soldered. A 1206 (.120" long by .060") wide is easier and probably gives the best balance of ease of assembly and size.

I have soldered 0402 and 0603 resistors by hand, but I needed a microscope. Now they even have 0201 and 0202 resistors. Those are so small that even a small breeze (like your breath) sends them off the bench into neverland.

John

Hi John,
I'm going through the Digikey catalog to assemble a parts list but not being totally electronic savvy I and I'm sure others could use a little more help. Case in point, I looked up the Diode 1N4148 and got 4 pages of product. Q1, Q2, D1 and D2 aren't a problem but could you be a little more specific for the caps and resistors, type, voltage, wattage etc. In you last post you mentioned size of the resistors. I'm not trying to miniaturize this unit to fit into the size of my distributor so using components that are fairly easy to handle would be ok.
Thanks again,
gbritnell

Give me an hour or so, I'll post a BOM with links to the parts.

John

See attached: The Bill of materials...

Cheers!
John

View attachment BOM.pdf

John,
Thanks ever so much. I certainly didn't want to be a pest about it but you fellows are the experts on this stuff and while I enjoyed reading all the posts on this subject sometimes I had no idea of what you were talking about.
gbritnell

gbritnell said:

John,
Thanks ever so much. I certainly didn't want to be a pest about it but you fellows are the experts on this stuff and while I enjoyed reading all the posts on this subject sometimes I had no idea of what you were talking about.
gbritnell

Click to expand...

No problem. It was my pleasure.

Maybe one day you'll share how you do radii and features in three axes with a manual mill! Or how you get rid of tooling marks so effectively. J/K!

John

gbritnell said:

John,
Thanks ever so much. I certainly didn't want to be a pest about it but you fellows are the experts on this stuff and while I enjoyed reading all the posts on this subject sometimes I had no idea of what you were talking about.
gbritnell

Click to expand...

gbritnell, I was looking at the BOM and just
to make sure trhat all angle are covered
c1&c3 could be mark 104 instead of the .1 micro
c2 could be marl 105 instead of 1 micro

canadianhorsepower said:

gbritnell, I was looking at the BOM and just
to make sure trhat all angle are covered
c1&c3 could be mark 104 instead of the .1 micro
c2 could be marl 105 instead of 1 micro

Click to expand...

Luc is right. To be clear, he's talking about the code marked on the side of capacitors.

The first two digits are the first two numbers in the capacitance value in picofarads, the last number is the number of zeros to append. So 105 is 10,00000 = 1,000,000 pF = 1 uF. 121 would be 120 pF and so on. The caps in the ignition circuit will be 104 or 105.

John

I was thinking, if I did a PCB layout and I had enough interest, I could have good quality boards made (FR4, double sided, with silkscreen, and plated through holes).

I'm not looking to make any money on this, but I'd need enough takers to cover the tooling costs at the PCB house (figure about $500-600). It could be made cheaper eliminating the silkscreen, but that's a big aid in assembly and test.

John

Hi,

If you look around you can find PCB-manufacterers who are much cheaper.

I make my prototype PCB's in china (more than 6 layers) or in Belgium/Holland and I never pay for tooling cast. A 2 layer eurocard PCB with soldermask and silkscreen will cast about 120euro or 150 dollar just for one piece.

I will look up the addresses and post them here this weekend if needed

Greetings,

Chris