opinion on power supply design workshop

AFAICT Ridley has a good reputation and that's a fairly normal price for a four-day hands-on seminar. I wouldn't really need it because I've done so many power converters that they come out of my ears by now. But if you are fairly new to this stuff it could be worthwhile. What is very important is to find out what and how much background is needed for this course and to make sure you have that. Possibly they require a solid background in control theory. Your five years in the game sound good but if in doubt, ask them.

Never seen a photo of Ray with such a short haircut. And he got older ... ... Oh!

Ray Ridley would be a great hands on teacher. Hey Joerg, IMHO you need this workshop! Harry

I like the "design and build" parts in that seminar, especially about transformers. Nothing lets you appreciate magnetics as much as when you have built the first one with your own hands.

Did I screw up somewhere? Or is it because of a really good brewsky they have in Atlanta?

If you are using off the shelf controllers, I'm not so sure this workshop is really needed. If you are rolling your own switchers, well you shouldn't be.

Thanks for the advice, it sounds really good, one concern I have is that it 's tied too much to their design software they sell, I'd hate to spend 4 da ys learning how to use a software package to design magnetics or power supp lies, I really do like the hands on aspect of it

Check out LTspice. It's free, educational, and has lots of support people.

Why not? Who wants to just copy eval boards?

And with digital power coming along, designing your own switcher may be the new thing.

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John Larkin Highland Technology Inc

Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators

Off-the-shelf controllers teach you nothing about the magnetics, intracacies of capacitors, things like that. Heck, they don't even tell you how an LC post-filter somewhere down the line can cause the whole chebang to go berserk. If someone isn't very familiar with all that (usually via blood, sweat and tears) such a workshop can be very worthwhile.

Almost anyone who has ever designed under super-tight budget for consumer gear will know otherwise. One of my early cases was when a new client had a working design but Maxim could not furnish production quantities of their MAX770. No surprise there. Since there wasn't any competing part with similar performance and price I ripped it all out, designed my own discrete solution, with current mode control and all, and that is still in production.

Uh, because eval boards are designed to provide good working circuits. Yes, a novel idea.

You do realize a chip all by its lonesome is way more reliable than something that uses firmware to run.

Funny how these cellphone manufacturers manage to source controller chips. Well I guess some people know how to run a business.

LTSpice is brilliant marketing and engineering. The spice works well, the schematic capture is on par with most pro software, and it seems to be just a tad bit easier to use LT parts than the competition. But LT makes good stuff, so that by itself isn't a drawback.

If you can make a product by simply copying more or less from an eval board you might as well outsource the whole "design". It's cheaper that way. The rubber really meets the road when the client or your marketing folks tell you that they want it in a tube the size of this here ballpoint pen.

Unless the company making the chip can't deliver quantities in time. Then the firmware solution, the discrete solution, or pretty much any other solution is a better solution. Because it avoids the single-source problem.

The competition seems to be in the process of shooting themselves in the foot by making new models progressively less LTspice compatible. TI especially.

Cheers

Phil Hobbs

Yeah, 50, maybe even 60 percent of the time. And they are loaded with expensive side parts, coincidentally all from the same manufacturer.

The nasty thing about a lot of eval boards is that they have jumpers and optional values for *everything*, so the eval board schematic is useless as a working example.

Copying circuits from appnotes and handbooks and mags isn't new! Some engineers literally do nothing else.

Depends. If a uP adds protections that an analog chip doesn't, then it's safer.

I often sim with an LT part that's close to what I need, and use something more "affordable" for the real thing.

Be sure to ask about sub-cycle oscillations!

LM339s and 74HC14's will be around for a while.

All the major players, LT included, are going toward "Spice" models that only work on their own simulators.

Have you not noted that _most_ LT SMPS models are encoded, and run on LTspice only.

Likewise TI is evolving toward TINA-only models.

And Analog Devices >:-} Ultimately only simulation via the "cloud".

The fun part is that _many_ of these encrypted models are crap... note that Analog Devices has NOT corrected the error(s) in the AD8218 model, though they stated correction "within the week" nearly three weeks ago. ...Jim Thompson

Also copying competors products. In the distant past, I designed marine radios. Motorola owned about 75% of the market. Absolutely none of my great (and not so great) ideas were even considered unless Motorola did it first. I had to wait several years with one such great idea, until Motorola finally produced a product that used it. Conservative management? Yep, but when you're small, you can't afford too many mistakes, so copying the competition seemed like a safe bet.

It also works backwards. The company decided to use 16.9MHz as an IF frequency because 10.7 was too low, and 21.4 would cause the then fashionable ULN2136 and ULN2111 IF chips to oscillate. The problem was that we also had to shift the 2nd IF from 455 to 446.25 KHz to avoid dead channels and mixer spurs. Someone in management thought that might look like a band-aid, so we didn't really emphasis the 2nd IF change in the documentation.

Within weeks of release, two competitors had 16.9 MHz IF radios, no doubt inspired by the crystal filter vendor leaking what we were doing in trade for a sale. The problem was that they missed the 2nd IF frequency change, and had some rather interesting problems. Somehow, I wasn't very sympathetic when they had one of their dealers call us for tech support about the problem.

Moral: If you're going to copy a circuit from the web, an app note, or from a competitor, it really helps to understand the circuit completely.

Some vendors don't know that, as has been evidenced numerous times. If a manufacturer cannot keep distributors properly stocked then it is not a good manufacturer. It is that simple.