S.E.D is disappearing

The numbers were to try to communicate the problem and get the discussion going. Reality can be filled in later.

Clueless. Another SEDer who talks more than thinks.

For 200 nsec? Four pairs, 0.6 times the speed of light... takes 30 feet by my calculator. OH, MICROseconds. My bad.

The problem isn't really the direct path from input to output, per se, rather the output capacitors are charged from the input before the PS even starts, making a controlled slow start impossible. The problem, here, is the 250mA max input current spec. If a current limiter is added before the boost, starting the boost may become a problem. This sort of operation isn't often specified.

Pretty much. I thought it was an interesting problem, though perhaps the good parts are a little hidden at first. This *is* a real problem and there is a known solution but I'd like to do better (if the project goes, it will be produced in the M/Y sorts of quantities). Since it's real, there are other (unstated) requirements, of course. As I noted before, temperature is a problem (forget supercaps) and , though not totally off the table, custom magnetics would have to be justified.

...and when I try to veer one onto the topic, I get called a troll. A

*clearly* on-topic discussion is a troll? Oh, well, I've now been called a troll by the best of them.

Show us, big guy. As you do, don't forget the rest of the problem.

BTW, you're the one calling people names, but don't let reality affect you.

d get you the help you need.

this time I will. The simplest option is a small series resistor on each on e, but you probably don't want to lose the efficiency. FETs can do the job more efficiently but require more control. Another option is 2 windings one driving each LED. Another is to split the switcher. And sometimes it may b e an option for the switcher to just limit i of the higher i led.

Next time try not to turn what seems to be a valid problem into trolling.

NT

Show me the numbers. Remember, I need a constant current source, not an RC decay.

Idiot. I proposed the problem. You can only handwave.

S.E.D is not disappearing. It has already disappeared with these kinds of replies.

d.

ould get you the help you need.

one, but you probably don't want to lose the efficiency. FETs can do the j ob more efficiently but require more control. Another option is 2 windings one driving each LED. Another is to split the switcher. And sometimes it ma y be an option for the switcher to just limit i of the higher i led.

.

So firstly you claim I can't design things simply because I refuse to do yo ur job for you. And 2nd you call me an idiot AND demand I do your design. G et lost.

krw is just one shade of ignorance better than bitrex. ...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

| 1962 |

I'm looking for work... see my website.

Thinking outside the box...producing elegant & economic solutions.

Me skimming this thread:

I'm thinking about that killfile filter.

NT

Jim-out-of-touch-with-reality-Thompson gets it wrong again. Krw has a serious cognitive deficit.

Bitrex just has opinions that Jim Thompson doesn't like. The fact that Jim confuses the two situations isn't a good sign.

--
Bill Sloman, Sydney

Then why are you here? Evidently you'd be a lot happier on facebook, or something.

No, I claim you cant design because you can't even parse the requirements and understand the first level of the onion. All you can do is make noises that it's a trivial problem that any idiot could do and complain about me being a troll for bringing a *real* problem, and not a simple one, to the group.

I'm not looking for anyone to do my job. I thought it was an interesting problem. One that you obviously can't handle but, for some reason seem to need to throw shit at. If you can't handle it, shut up. No one would have known.

Thompson thinks I'm a lefty, so take the comment from where it comes.

Please do.

If the input is 7 volts and the output is 6 volts at 250ma , why not just drop the extra volt with a 4 ohm resistor? That would give you 85% efficiency. Do you want more?

It's a little more complicated. The input is limited to 7V at 250mA, but the output is a 10A pulse with a 2% duty cycle into two series LEDs (assume forward voltage of 6V). Energy has to be stored somewhere/how.