Forums

Why are IGBT's used in ignitions so much?

Started by Joerg April 28, 2018
On Mon, 30 Apr 2018 06:57:33 -0700, Joerg <news@analogconsultants.com>
wrote:

>On 2018-04-29 15:08, Jim Thompson wrote:
[snip].
> >> >> Actually I was thinking dissipation in the coil primary with no load. >> My scheme will apply 350V to the primary, period, secondary loaded or >> not; and the switch device only sees 350V, irrespective of load. >> > >That is what IIRC most capacitive discharge ignition circuits do. AFAIK >that comes at the price of a shorter spark versus inductive.
Yep. That's why I couldn't sell it to Ford, even with my later embellishment, multi-fire. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions, by understanding what nature is hiding. "It is not in doing what you like, but in liking what you do that is the secret of happiness." -James Barrie
On Mon, 30 Apr 2018 10:25:04 -0400, Neon John <no@never.com> wrote:

>On Sun, 29 Apr 2018 13:24:39 -0700 (PDT), whit3rd <whit3rd@gmail.com> >wrote: > >>Aggressive marketing, obviously. Take the typical IROC (right-out-of-college) >>engineer, assign it to make an ignition, and Google will >>pull him into a maze of IGBT datasheets. > >You could not be more wrong. I'm still an engineering consultant to >Ford's Dearborn engine development lab so I know a thing or two about >how things are done. > >Ford (or more likely their captive contractor Delco) doesn't go out to >the marketplace and buy something that is close to what they need. > >When tens of millions of a part are involved, they develop a >functional specification for a part that is EXACTLY what they need and >put that out for bid. The respondents are first evaluated as to their >ability to handle the volume. Then Delco invites chip makers to >submit a bid and some sample parts. > >The sample parts are tested to standards that few other industries >require. With millions of parts involved, even a 0.0001% failure rate >would cause a massive recall and massive bad publicity. > >They'll shave pennies in other areas. Eliminating packaging and using >a COB die is now common. > >The finished assembly, say a coil-on-plug is also massively tested >under extraordinary conditions, both in the lab and on the road. > >Ford has a proving ground facility in Greenland inside the Arctic >circle for cold weather testing. A similar facility is located at a >desert equatorial location (I forget where) for hot weather testing. > >After the assembly is accepted for production, the finished product is >statistically sampled continuously to verify that performance remains >the same throughout the part's life. > >The chip foundry, being geared up for very high production, realizes >that the part can be useful for other things and so markets it outside >the industry and at a low price. > >And BTW, a newly graduated engineer is never assigned "go design a >widget" project. Newly hired engineers undergo an apprenticeship that >lasts about 4 years. During that time they learn to do things the >automotive way. Only seniority and accomplishments leads to more >complex projects. > >One of my very good MechE friends at Ford is about to retire. He has >told me that he was in his 30s before he was assigned a significant >design project. > >John >John DeArmond >http://www.neon-john.com >http://www.tnduction.com >Tellico Plains, Occupied TN >See website for email address
Then there was a day, long past, say some 54 years ago, when some lad, age of 24, grabbed the ball, and put solid state regulators into Ford, GM, Chrysler and American Motors >:-} ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions, by understanding what nature is hiding. "It is not in doing what you like, but in liking what you do that is the secret of happiness." -James Barrie
"Jim Thompson" <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in 
message news:0qfeed55uushkpi9eie1nijrh63vpgnkt6@4ax.com...
> On Mon, 30 Apr 2018 10:25:04 -0400, Neon John <no@never.com> wrote: > >>On Sun, 29 Apr 2018 13:24:39 -0700 (PDT), whit3rd <whit3rd@gmail.com> >>wrote: >> >>>Aggressive marketing, obviously. Take the typical IROC >>>(right-out-of-college) >>>engineer, assign it to make an ignition, and Google will >>>pull him into a maze of IGBT datasheets. >> >>You could not be more wrong. I'm still an engineering consultant to >>Ford's Dearborn engine development lab so I know a thing or two about >>how things are done. >> >>Ford (or more likely their captive contractor Delco) doesn't go out to >>the marketplace and buy something that is close to what they need. >> >>When tens of millions of a part are involved, they develop a >>functional specification for a part that is EXACTLY what they need and >>put that out for bid. The respondents are first evaluated as to their >>ability to handle the volume. Then Delco invites chip makers to >>submit a bid and some sample parts. >> >>The sample parts are tested to standards that few other industries >>require. With millions of parts involved, even a 0.0001% failure rate >>would cause a massive recall and massive bad publicity. >> >>They'll shave pennies in other areas. Eliminating packaging and using >>a COB die is now common. >> >>The finished assembly, say a coil-on-plug is also massively tested >>under extraordinary conditions, both in the lab and on the road. >> >>Ford has a proving ground facility in Greenland inside the Arctic >>circle for cold weather testing. A similar facility is located at a >>desert equatorial location (I forget where) for hot weather testing. >> >>After the assembly is accepted for production, the finished product is >>statistically sampled continuously to verify that performance remains >>the same throughout the part's life. >> >>The chip foundry, being geared up for very high production, realizes >>that the part can be useful for other things and so markets it outside >>the industry and at a low price. >> >>And BTW, a newly graduated engineer is never assigned "go design a >>widget" project. Newly hired engineers undergo an apprenticeship that >>lasts about 4 years. During that time they learn to do things the >>automotive way. Only seniority and accomplishments leads to more >>complex projects. >> >>One of my very good MechE friends at Ford is about to retire. He has >>told me that he was in his 30s before he was assigned a significant >>design project. >> >>John >>John DeArmond >>http://www.neon-john.com >>http://www.tnduction.com >>Tellico Plains, Occupied TN >>See website for email address > > Then there was a day, long past, say some 54 years ago, when some lad, > age of 24, grabbed the ball, and put solid state regulators into Ford, > GM, Chrysler and American Motors >:-} > > ...Jim Thompson > --
Was the first solid state regulator used in a generator or alternator? Regards
On Mon, 30 Apr 2018 12:25:29 -0400, "tom" <tmiller11147@verizon.net>
wrote:

> >"Jim Thompson" <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in >message news:0qfeed55uushkpi9eie1nijrh63vpgnkt6@4ax.com... >> On Mon, 30 Apr 2018 10:25:04 -0400, Neon John <no@never.com> wrote: >> >>>On Sun, 29 Apr 2018 13:24:39 -0700 (PDT), whit3rd <whit3rd@gmail.com> >>>wrote: >>> >>>>Aggressive marketing, obviously. Take the typical IROC >>>>(right-out-of-college) >>>>engineer, assign it to make an ignition, and Google will >>>>pull him into a maze of IGBT datasheets. >>> >>>You could not be more wrong. I'm still an engineering consultant to >>>Ford's Dearborn engine development lab so I know a thing or two about >>>how things are done. >>> >>>Ford (or more likely their captive contractor Delco) doesn't go out to >>>the marketplace and buy something that is close to what they need. >>> >>>When tens of millions of a part are involved, they develop a >>>functional specification for a part that is EXACTLY what they need and >>>put that out for bid. The respondents are first evaluated as to their >>>ability to handle the volume. Then Delco invites chip makers to >>>submit a bid and some sample parts. >>> >>>The sample parts are tested to standards that few other industries >>>require. With millions of parts involved, even a 0.0001% failure rate >>>would cause a massive recall and massive bad publicity. >>> >>>They'll shave pennies in other areas. Eliminating packaging and using >>>a COB die is now common. >>> >>>The finished assembly, say a coil-on-plug is also massively tested >>>under extraordinary conditions, both in the lab and on the road. >>> >>>Ford has a proving ground facility in Greenland inside the Arctic >>>circle for cold weather testing. A similar facility is located at a >>>desert equatorial location (I forget where) for hot weather testing. >>> >>>After the assembly is accepted for production, the finished product is >>>statistically sampled continuously to verify that performance remains >>>the same throughout the part's life. >>> >>>The chip foundry, being geared up for very high production, realizes >>>that the part can be useful for other things and so markets it outside >>>the industry and at a low price. >>> >>>And BTW, a newly graduated engineer is never assigned "go design a >>>widget" project. Newly hired engineers undergo an apprenticeship that >>>lasts about 4 years. During that time they learn to do things the >>>automotive way. Only seniority and accomplishments leads to more >>>complex projects. >>> >>>One of my very good MechE friends at Ford is about to retire. He has >>>told me that he was in his 30s before he was assigned a significant >>>design project. >>> >>>John >>>John DeArmond >>>http://www.neon-john.com >>>http://www.tnduction.com >>>Tellico Plains, Occupied TN >>>See website for email address >> >> Then there was a day, long past, say some 54 years ago, when some lad, >> age of 24, grabbed the ball, and put solid state regulators into Ford, >> GM, Chrysler and American Motors >:-} >> >> ...Jim Thompson >> -- > >Was the first solid state regulator used in a generator or alternator? > >Regards >
The one's I designed were for alternators, IC chip plus a discrete Darlington... assembled on a "lead frame"... if I can find a picture, I'll post. But I believe there were generator regulators made up of discrete devices, but, IIRC, still used relays to control the field and reverse conduction... the semiconductors just added accuracy to the sensing voltage. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions, by understanding what nature is hiding. "It is not in doing what you like, but in liking what you do that is the secret of happiness." -James Barrie
mandag den 30. april 2018 kl. 16.00.43 UTC+2 skrev Joerg:
> On 2018-04-29 12:19, Lasse Langwadt Christensen wrote: > > l&oslash;rdag den 28. april 2018 kl. 22.22.54 UTC+2 skrev Joerg: > >> Considering the typical saturation voltages of >1V it doesn't look > >> attractive yet they are popular: > >> > >> https://www.fairchildsemi.com/datasheets/FG/FGD3040G2_F085.pdf > >> > >> Why? > >> > >> There are plenty of cheap MOSFETs that are in the low tens of milliohms > >> and thus show only a fraction of the losses while the coil current ramps > >> up. You'd just have to add a zener from drain to gate in case the spark > >> plug goes bad, the wire comes off or the controller lets the dwell time > >> run out of hand. Plus some other gate protection but that's no problem. > >> > > > > http://www.st.com/content/ccc/resource/technical/document/application_note/8d/46/36/a7/b6/f2/45/10/CD00003911.pdf/files/CD00003911.pdf/jcr:content/translations/en.CD00003911.pdf > > > > > > Thanks, I have read papers like that. On of the things that puzzles me > is evident in figure 10, over 1V in Vcesat. A FET can run circles around > that and run with much less cooling, meaning an overall smaller module, > less weight.
You can use mosfets, A guy I know that design and builds aftermarket ECUs uses irfp450 (afair) for many years. I think he uses ignition igbts now, spec'ced for 5V drive and build in clamp
mandag den 30. april 2018 kl. 16.07.59 UTC+2 skrev Joerg:
> On 2018-04-29 13:24, whit3rd wrote: > > On Saturday, April 28, 2018 at 1:22:54 PM UTC-7, Joerg wrote: > >> Considering the typical saturation voltages of >1V it doesn't look > >> attractive yet they are popular: > >> > >> https://www.fairchildsemi.com/datasheets/FG/FGD3040G2_F085.pdf > >> > >> Why? > > > > Aggressive marketing, obviously. Take the typical IROC (right-out-of-college) > > engineer, assign it to make an ignition, and Google will > > pull him into a maze of IGBT datasheets. > > > > I remember the days when IGBTs came out and lots of less experienced > used them for just about anything. Their designs worked but were > expensive in production. > > > > I'm fond of the old Mark10 design (Heathkit, too) with capacitive discharge, > > which works fine with forty-year-old SCRs. > > > > My car has a potted mystery module and was designed with a > > LONG harness connection to the coil and reluctor sensor. > > > > There was no active intelligence used in the parts of the design that I can see. > > > > My Citroen had a really cool system. The coil's secondary fed both plugs > in its two-cylinder engine (wasted spark method) which meant no > distributor. It also meant no distributor could go bad. However, it > could make for interesting effects when hand-cranking it on a cold day. > You had to make sure no white or particularly clean car war parked > behind and nobody stood near the exhaust. Once the bang was so bad that > the 2nd muffler pot fell off and started rolling down the street. > Embarrassing. >
almost everything now is waste spark with pairs of plugs in series, or coil-on-plug
On 2018-04-30 09:45, Lasse Langwadt Christensen wrote:
> mandag den 30. april 2018 kl. 16.00.43 UTC+2 skrev Joerg: >> On 2018-04-29 12:19, Lasse Langwadt Christensen wrote: >>> l&oslash;rdag den 28. april 2018 kl. 22.22.54 UTC+2 skrev Joerg: >>>> Considering the typical saturation voltages of >1V it doesn't look >>>> attractive yet they are popular: >>>> >>>> https://www.fairchildsemi.com/datasheets/FG/FGD3040G2_F085.pdf >>>> >>>> Why? >>>> >>>> There are plenty of cheap MOSFETs that are in the low tens of milliohms >>>> and thus show only a fraction of the losses while the coil current ramps >>>> up. You'd just have to add a zener from drain to gate in case the spark >>>> plug goes bad, the wire comes off or the controller lets the dwell time >>>> run out of hand. Plus some other gate protection but that's no problem. >>>> >>> >>> http://www.st.com/content/ccc/resource/technical/document/application_note/8d/46/36/a7/b6/f2/45/10/CD00003911.pdf/files/CD00003911.pdf/jcr:content/translations/en.CD00003911.pdf >>> >>> >> >> Thanks, I have read papers like that. On of the things that puzzles me >> is evident in figure 10, over 1V in Vcesat. A FET can run circles around >> that and run with much less cooling, meaning an overall smaller module, >> less weight. > > You can use mosfets, A guy I know that design and builds aftermarket ECUs > uses irfp450 (afair) for many years. I think he uses ignition igbts now, > spec'ced for 5V drive and build in clamp >
400mohms Rdson is a bit high though, gets warm. -- Regards, Joerg http://www.analogconsultants.com/
On 2018-04-30 09:47, Lasse Langwadt Christensen wrote:
> mandag den 30. april 2018 kl. 16.07.59 UTC+2 skrev Joerg: >> On 2018-04-29 13:24, whit3rd wrote: >>> On Saturday, April 28, 2018 at 1:22:54 PM UTC-7, Joerg wrote: >>>> Considering the typical saturation voltages of >1V it doesn't look >>>> attractive yet they are popular: >>>> >>>> https://www.fairchildsemi.com/datasheets/FG/FGD3040G2_F085.pdf >>>> >>>> Why? >>> >>> Aggressive marketing, obviously. Take the typical IROC (right-out-of-college) >>> engineer, assign it to make an ignition, and Google will >>> pull him into a maze of IGBT datasheets. >>> >> >> I remember the days when IGBTs came out and lots of less experienced >> used them for just about anything. Their designs worked but were >> expensive in production. >> >> >>> I'm fond of the old Mark10 design (Heathkit, too) with capacitive discharge, >>> which works fine with forty-year-old SCRs. >>> >>> My car has a potted mystery module and was designed with a >>> LONG harness connection to the coil and reluctor sensor. >>> >>> There was no active intelligence used in the parts of the design that I can see. >>> >> >> My Citroen had a really cool system. The coil's secondary fed both plugs >> in its two-cylinder engine (wasted spark method) which meant no >> distributor. It also meant no distributor could go bad. However, it >> could make for interesting effects when hand-cranking it on a cold day. >> You had to make sure no white or particularly clean car war parked >> behind and nobody stood near the exhaust. Once the bang was so bad that >> the 2nd muffler pot fell off and started rolling down the street. >> Embarrassing. >> > > almost everything now is waste spark with pairs of plugs in series, > or coil-on-plug >
I haven't seen wasted spark in a long time. Coil-on-plug usually had a personal coil for each plug. Our cars (Mitsubishi Montero Sport and Toyota Corolla) still use one coil and distributor but they are about 20 years old. -- Regards, Joerg http://www.analogconsultants.com/
mandag den 30. april 2018 kl. 18.53.46 UTC+2 skrev Joerg:
> On 2018-04-30 09:45, Lasse Langwadt Christensen wrote: > > mandag den 30. april 2018 kl. 16.00.43 UTC+2 skrev Joerg: > >> On 2018-04-29 12:19, Lasse Langwadt Christensen wrote: > >>> l&oslash;rdag den 28. april 2018 kl. 22.22.54 UTC+2 skrev Joerg: > >>>> Considering the typical saturation voltages of >1V it doesn't look > >>>> attractive yet they are popular: > >>>> > >>>> https://www.fairchildsemi.com/datasheets/FG/FGD3040G2_F085.pdf > >>>> > >>>> Why? > >>>> > >>>> There are plenty of cheap MOSFETs that are in the low tens of milliohms > >>>> and thus show only a fraction of the losses while the coil current ramps > >>>> up. You'd just have to add a zener from drain to gate in case the spark > >>>> plug goes bad, the wire comes off or the controller lets the dwell time > >>>> run out of hand. Plus some other gate protection but that's no problem. > >>>> > >>> > >>> http://www.st.com/content/ccc/resource/technical/document/application_note/8d/46/36/a7/b6/f2/45/10/CD00003911.pdf/files/CD00003911.pdf/jcr:content/translations/en.CD00003911.pdf > >>> > >>> > >> > >> Thanks, I have read papers like that. On of the things that puzzles me > >> is evident in figure 10, over 1V in Vcesat. A FET can run circles around > >> that and run with much less cooling, meaning an overall smaller module, > >> less weight. > > > > You can use mosfets, A guy I know that design and builds aftermarket ECUs > > uses irfp450 (afair) for many years. I think he uses ignition igbts now, > > spec'ced for 5V drive and build in clamp > > > > 400mohms Rdson is a bit high though, gets warm.
it is only on for a few milliseconds while the current is ramping up every (other) revolution
On 2018-04-30 10:10, Lasse Langwadt Christensen wrote:
> mandag den 30. april 2018 kl. 18.53.46 UTC+2 skrev Joerg: >> On 2018-04-30 09:45, Lasse Langwadt Christensen wrote: >>> mandag den 30. april 2018 kl. 16.00.43 UTC+2 skrev Joerg: >>>> On 2018-04-29 12:19, Lasse Langwadt Christensen wrote: >>>>> l&oslash;rdag den 28. april 2018 kl. 22.22.54 UTC+2 skrev Joerg: >>>>>> Considering the typical saturation voltages of >1V it doesn't look >>>>>> attractive yet they are popular: >>>>>> >>>>>> https://www.fairchildsemi.com/datasheets/FG/FGD3040G2_F085.pdf >>>>>> >>>>>> Why? >>>>>> >>>>>> There are plenty of cheap MOSFETs that are in the low tens of milliohms >>>>>> and thus show only a fraction of the losses while the coil current ramps >>>>>> up. You'd just have to add a zener from drain to gate in case the spark >>>>>> plug goes bad, the wire comes off or the controller lets the dwell time >>>>>> run out of hand. Plus some other gate protection but that's no problem. >>>>>> >>>>> >>>>> http://www.st.com/content/ccc/resource/technical/document/application_note/8d/46/36/a7/b6/f2/45/10/CD00003911.pdf/files/CD00003911.pdf/jcr:content/translations/en.CD00003911.pdf >>>>> >>>>> >>>> >>>> Thanks, I have read papers like that. On of the things that puzzles me >>>> is evident in figure 10, over 1V in Vcesat. A FET can run circles around >>>> that and run with much less cooling, meaning an overall smaller module, >>>> less weight. >>> >>> You can use mosfets, A guy I know that design and builds aftermarket ECUs >>> uses irfp450 (afair) for many years. I think he uses ignition igbts now, >>> spec'ced for 5V drive and build in clamp >>> >> >> 400mohms Rdson is a bit high though, gets warm. > > it is only on for a few milliseconds while the current is > ramping up every (other) revolution >
True but at high rpm it does add up. In automotive they usually skimp on every bit of PCB copper or aluminum. -- Regards, Joerg http://www.analogconsultants.com/