Automotive '12V' Power

That's around the limit for some processes, at least older ones. For my first HV chip design we could only get onto an automotive process and that resulted in us having to throttle our peak pulse levels from 60V to

The worst case would be lights out, no A/C and not a lot of other load. One has to design towards worst case. Unfortunately that isn't always done in automotive, which is why I have some level of distrust when it comes to electronic cricuitry in cars. I prefer those with the least amount of electronics in there because those tend to break down less often.

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And there's been talk of going to 48V batteries in cars ;-) ...Jim Thompson

Larkin

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That talk has been going on since decades. Heck, even American trucks are still on a 12V system.

Hybrids can have rails with hundreds of volts but there is a lot more engineering diligence going into those, versus some of the regular automotive electronics.

I have been blessed by always working for companies with bad marketing (including my own) so have had the chance to work on all sorts of bizarre and disconnected stuff. Even the things that seemed to be failures at the time have usually turned out to be useful in the long term.

It's interesting that there's value in being very good at something, but there's also a lot of value at being pretty good at a lot of things. JF and JT seem to have the narrow focus, so avoid all sorts of fun threads... physics, optics, signal processing, fast stuff, all that not-555-not-analog-transistor stuff.

He and JT dislike me for some reason. JF once told me he loved me (creepy!) and JT wanted to be "best of friends" (almost as creepy), and now they dislike me so much they don't even make sense.

Some people are really weird.

John

start it with 480 V AC 3 phase , the car is accelerated past the speed limit, the chassis shot full of holes by the FBI, the neighbours hold a barbecue under the engine block, shooting up through the van Allen belt the cars radio antenna generates a huge EMF because of the earth magnetic field, it gets out into space, is entered by an alian who uses the cigarette lighter to charge his fasor, and in a case like that you better add an extra zener.

And the worst part is that the hamburgers get burned beyond recognition.

Hey, tomorrow is the 4th Of July, the traditional USA beer-and-barbeque-and-fireworks day. Do you have anything like that?

We're up in the mountains to get away from it all, and it seems like everybody else has the same idea. It's shocking how many cars have skis on their racks.

John

Most big rigs are 24V

I was talking to a mechanic who told me they couldn't yet work on "electric" cars... their "body removal tool" hadn't come in yet. And the "body removal tool" wasn't for removing the car body ;-)

Unfortunately I find most mechanics can't even locate a broken wire :-( ...Jim Thompson

It wasn't just the vacuum wipers that sucked. ;)

Cheers

Phil Hobbs

I finally got around to trying this again - it seems fine. 75V input step with ~50mV disturbance of the output. Pretty impressive.

The performance above 100V was even more impressive until I realised that the output had failed short-circuit to ground :)

Nonsense! Having been right there at the beginnings of integrating automotive electronics I can assure you that there were MANY design reviews. Automobile people tended (at least back then) to be very cautious, a recall can be extraordinarily expensive.

I can remember a case, at Ford, where there was a carburetor issue... an air-bleed hole on the drawings was left-out and/or missed. The engineers involved were sent to the production line to personally drill the missing holes, to much tittering and verbal abuse from the production line workers.

Thus mistakes/omissions were few and far between :-)

BTW, Ford wasn't "bailed out". ...Jim Thompson

Jim Thompson wrote in news: snipped-for-privacy@4ax.com:

the "body removal tool" is a long plastic "mophandle" with a heavy insulated wire hook or loop on the end,like what a lifeguard at a pool uses for a swimmer in distress,but without the aluminum handle.

We had one at the Tektronix Orlando Service Center.(now defunct...)

We also had a "kill button" that would shut off ALL the power in the shop.

The biggest are not, but in any case, the 48V was part of a "smarter gas car" package: electronic valve control, integral flywheel starter/alternator, no-idling - the previous parts would let you stand on the gas when the light turns green, and away you go. Plus accessory motors with real umph.

It needed all LED/discharge illumination, since 48V filaments would be fragile. Last I heard, a long time ago, Detroit wanted suppliers to eat the R&D for everything, and they'd buy it. Gee Thanks.

And little change in the accessories...so far.

I had that "kill button" at my lab in GenRad, plus a rule that two technicians must be present during ANY work on off-line switchers. ...Jim Thompson

Did you lose the schottky diode?

John

I wouldn't think so - it was a 100V type - but I have not looked in to exactly what happened yet.

How many decades ago was that?

But Chrysler and GM were. I had a Chrysler for a few years. Alternator kept falling off (!), seriously. Shop says "Oh yeah, happens a lot, so we've got plenty of those in stock". Turns out they had "designed in" an aluminum strut. Finally I had it and made my own strut, from steel, never fell off again. That didn't leave much faith in whatever review process there might have been.

It wasn't the only brand where that happened.

Now! Now! Don't be a rude young whippersnapper ;-)

I always thought Chrysler products were shit! During the early days of smog controls they couldn't make a car that met CA standards and start easily on a foggy morning :-(

But, in your case, it may well have been your black thumb ;-) ...Jim Thompson

No, as I wrote I "redesigned" it and that made it work :-)

Then it rusted out, shortly after the six-year "no rusting through" warranty was up. This cemented my decision not to buy any more cars of that brand. In fact, our whole family didn't. So I bought a 1987 Audi, a big old fat one. Never broke down, still running, it's going to celebrate its 24th birthday with not a speck of rust. Now that's quality.

I've not seen rust on a car since I moved to Arizona ;-) ...Jim Thompson

Not the ones where I was involved in electronics design. AFAIK this one still runs on 12V despite the fact that the company is owned by Daimler who builds 24V truck in Europe, and it certainly qualifies as a big rig:

This is the battery that goes into it, 12V and about a kilo-amp of cranking capability: