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Simulation software for DC/DC converter

"nescafe" wrote in message news:jq31tq$nu3$ snipped-for-privacy@l01news1.ot.hr...

look=20

I'm still a bit confused about the overall design of this power supply. = The=20 transformer is usually an integral part of the design and it does not = make=20 sense that it "works perfectly" until the transformer is connected. Your =

other reply says that your simulation is missing MOSFETs as well as some = ICs=20 that do not seem to be typical of a power supply design (4040's 4060's,=20

4081). Mostly we would need the basic output components, such as the = MOSFETs=20 and/or BJTs, and even a simple model of the transformer, and the various =

protection components you mention.

You can simulate the drive with a pulse train. Then you should be able = to=20 run a time domain simulation of the startup and watch the currents and=20 voltages over the first several mSec or so, depending on drive = frequency. As=20 an example, see my attached LTSpice file for a DC-DC converter I = designed.=20 But I am actually creating the PWM with a PIC18F684.

This design creates 300VDC from 12VDC, and I have built it and it works. = But=20 I am having some problems with it and that's what the prototype is for. = My=20 actual scope trace looks very much like the simulator, but then at = voltages=20 over about 12.5 volts the current shoots up and it becomes unstable. = That's=20 a discussion for another thread.

Please provide as many relevant details as possible, and don't bother = with=20 extraneous items like the ICs you mention, unless they are a critical = part=20 of the design. And then you need to explain what they do and why they = are=20 needed. It seems that counters and an AND gate are unusual for a power=20 supply. You have stimulated my curiosity!

Good luck,

Paul

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D

Version 4 SHEET 1 880 680 WIRE 256 96 224 96 WIRE -208 112 -272 112 WIRE 176 112 -208 112 WIRE -272 128 -272 112 WIRE -208 128 -208 112 WIRE 256 128 256 96 WIRE 320 128 256 128 WIRE 432 128 384 128 WIRE 496 128 432 128 WIRE 560 128 496 128 WIRE 592 128 560 128 WIRE 0 144 -160 144 WIRE 64 144 0 144 WIRE 96 144 64 144 WIRE 496 144 496 128 WIRE -272 192 -432 192 WIRE 224 192 224 96 WIRE 320 208 288 208 WIRE 432 208 432 128 WIRE 432 208 384 208 WIRE 592 208 592 128 WIRE -640 240 -704 240 WIRE -576 240 -640 240 WIRE -496 240 -576 240 WIRE -448 240 -496 240 WIRE -208 240 -208 208 WIRE -208 240 -448 240 WIRE 96 240 96 224 WIRE 96 240 -208 240 WIRE 288 240 288 208 WIRE 496 240 496 208 WIRE 496 240 288 240 WIRE 96 256 96 240 WIRE 0 272 0 224 WIRE 288 272 288 240 WIRE 288 272 224 272 WIRE 320 272 288 272 WIRE 416 272 384 272 WIRE -320 288 -384 288 WIRE -80 288 -256 288 WIRE 496 288 496 240 WIRE -384 304 -384 288 WIRE -640 320 -640 240 WIRE -704 336 -704 240 WIRE -256 336 -256 288 WIRE 80 336 0 336 WIRE 96 336 80 336 WIRE -496 368 -496 240 WIRE -80 368 -80 288 WIRE 96 368 -80 368 WIRE 192 368 160 368 WIRE 256 368 256 128 WIRE 320 368 256 368 WIRE 416 368 416 272 WIRE 416 368 384 368 WIRE 496 368 496 352 WIRE 496 368 416 368 WIRE 592 368 592 288 WIRE 592 368 496 368 WIRE -160 384 -160 144 WIRE 0 384 0 336 WIRE 592 384 592 368 WIRE -576 416 -576 240 WIRE 96 416 48 416 WIRE 192 416 192 368 WIRE 192 416 160 416 WIRE 736 416 192 416 WIRE 176 432 176 112 WIRE 384 432 176 432 WIRE 336 448 112 448 WIRE 416 448 336 448 WIRE 528 448 496 448 WIRE 736 448 736 416 WIRE -320 464 -320 288 WIRE -208 464 -320 464 WIRE -80 464 -80 368 WIRE -48 464 -80 464 WIRE 384 464 384 432 WIRE -80 480 -160 480 WIRE 176 480 176 432 WIRE 272 480 256 480 WIRE 320 480 272 480 WIRE 352 480 320 480 WIRE -320 496 -320 464 WIRE 48 496 48 416 WIRE 48 496 -320 496 WIRE 272 496 272 480 WIRE 528 496 528 448 WIRE 528 496 416 496 WIRE 576 496 528 496 WIRE 672 496 656 496 WIRE 336 512 336 448 WIRE 352 512 336 512 WIRE -704 528 -704 400 WIRE -640 528 -640 384 WIRE -640 528 -704 528 WIRE -576 528 -576 480 WIRE -576 528 -640 528 WIRE -544 528 -576 528 WIRE -496 528 -496 448 WIRE -496 528 -544 528 WIRE -432 528 -432 192 WIRE -432 528 -496 528 WIRE -384 528 -384 384 WIRE -384 528 -432 528 WIRE -304 528 -384 528 WIRE -256 528 -256 416 WIRE -256 528 -304 528 WIRE -208 528 -256 528 WIRE -80 528 -80 480 WIRE -80 528 -128 528 WIRE 0 528 0 480 WIRE 0 528 -80 528 WIRE 32 528 0 528 WIRE 112 528 112 448 WIRE 320 528 320 480 WIRE -304 592 -304 528 WIRE 272 592 272 576 WIRE 272 592 -304 592 WIRE 320 592 272 592 WIRE 384 592 384 528 WIRE 384 592 320 592 WIRE 736 592 736 544 WIRE 736 592 384 592 WIRE -544 608 -544 528 FLAG -544 608 0 FLAG 592 384 0 FLAG 560 128 Vout FLAG -448 240 in FLAG 64 144 m1 FLAG 80 336 m2 SYMBOL ind2 80 128 R0 SYMATTR InstName L1 SYMATTR Value 180=B5 SYMATTR Type ind SYMATTR SpiceLine Rser=3D100u SYMBOL ind2 80 240 R0 WINDOW 0 45 35 Left 2 WINDOW 3 41 61 Left 2 SYMATTR InstName L2 SYMATTR Value 180=B5 SYMATTR Type ind SYMATTR SpiceLine Rser=3D100u SYMBOL ind2 240 176 M0 SYMATTR InstName L3 SYMATTR Value 32m SYMATTR Type ind SYMATTR SpiceLine Rser=3D10m SYMBOL nmos -208 384 R0 SYMATTR InstName M1 SYMATTR Value IRFZ44N SYMBOL nmos -48 384 R0 SYMATTR InstName M2 SYMATTR Value IRFZ44N SYMBOL voltage -496 352 R0 WINDOW 123 0 0 Left 2 WINDOW 39 24 132 Left 2 SYMATTR SpiceLine Rser=3D8m SYMATTR InstName V1 SYMATTR Value 12 SYMBOL diode 384 288 M270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D2 SYMATTR Value MUR460 SYMBOL diode 320 224 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D3 SYMATTR Value MUR460 SYMBOL polcap 480 288 R0 WINDOW 3 24 64 Left 2 SYMATTR Value 1000=B5 SYMATTR InstName C1 SYMATTR Description Capacitor SYMATTR Type cap SYMATTR SpiceLine V=3D400 Irms=3D30 Rser=3D0.2 Lser=3D0 SYMBOL res 576 192 R0 SYMATTR InstName R1 SYMATTR Value 300 SYMBOL voltage -384 288 R0 WINDOW 123 0 0 Left 2 WINDOW 39 -43 57 Left 2 WINDOW 3 148 308 Left 2 SYMATTR SpiceLine Rser=3D47 SYMATTR Value PULSE(0 10 0.5u 10n 10n 499u 1000u 100) SYMATTR InstName V2 SYMBOL voltage -256 320 R0 WINDOW 123 0 0 Left 2 WINDOW 39 -43 57 Left 2 WINDOW 3 21 307 Left 2 SYMATTR SpiceLine Rser=3D47 SYMATTR Value PULSE(0 10 500.5u 10n 10n 499u 1000u 100) SYMATTR InstName V3 SYMBOL diode 320 144 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D1 SYMATTR Value MUR460 SYMBOL diode 384 384 M270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D4 SYMATTR Value MUR460 SYMBOL polcap -592 416 R0 WINDOW 3 24 64 Left 2 SYMATTR Value 2200=B5 SYMATTR InstName C2 SYMATTR Description Capacitor SYMATTR Type cap SYMATTR SpiceLine V=3D25 Irms=3D20 Rser=3D100m Lser=3D0 SYMBOL polcap 480 144 R0 WINDOW 3 24 64 Left 2 SYMATTR Value 1000=B5 SYMATTR InstName C3 SYMATTR Description Capacitor SYMATTR Type cap SYMATTR SpiceLine V=3D400 Irms=3D30 Rser=3D0.2 Lser=3D0 SYMBOL cap -656 320 R0 SYMATTR InstName C5 SYMATTR Value .47=B5 SYMATTR SpiceLine V=3D250 Rser=3D100u SYMBOL res -16 128 R0 SYMATTR InstName R2 SYMATTR Value 10 SYMBOL cap -16 272 R0 SYMATTR InstName C4 SYMATTR Value 0.47=B5 SYMBOL schottky -688 400 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D5 SYMATTR Value MBRB2545CT SYMATTR Description Diode SYMATTR Type diode SYMBOL res -112 512 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value .001 SYMBOL res 128 512 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 1k SYMBOL schottky 96 352 M90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D6 SYMATTR Value 1N5818 SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 96 400 M90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D7 SYMATTR Value 1N5818 SYMATTR Description Diode SYMATTR Type diode SYMBOL Opamps\\LT1013 384 432 R0 SYMATTR InstName U1 SYMBOL res 288 592 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R5 SYMATTR Value 1k SYMBOL res 160 496 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R6 SYMATTR Value 100k SYMBOL res 400 464 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R7 SYMATTR Value 100k SYMBOL res -224 112 R0 SYMATTR InstName R8 SYMATTR Value 10 SYMBOL cap -288 128 R0 SYMATTR InstName C6 SYMATTR Value .47=B5 SYMATTR SpiceLine V=3D250 Rser=3D100u SYMBOL npn 672 448 R0 SYMATTR InstName Q1 SYMATTR Value 2N3904 SYMBOL res 672 480 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 1k SYMBOL cap 304 528 R0 SYMATTR InstName C7 SYMATTR Value .47=B5 SYMATTR SpiceLine V=3D250 Rser=3D100u TEXT 32 88 Left 2 !K1 L1 L2 L3 0.995 TEXT -528 632 Left 2 !.tran 0 200m 0 1u startup TEXT -352 88 Left 2 ;Primary 2x8 turns 2V/turn at 600 Hz

Reply to
P E Schoen
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when it

engineers. Big

LTC's

I can buy the controller and driver, and still have money left over, for that LTC charges. Do they have one with the controller and four (pairs) that'll drive 33V?

Price is a strong function of value and quantity. I *long* ago stopped worrying about single-sourced parts. There are just too many to lay awake at night worrying about one more.

Reply to
krw

they

the

You act like there was no higher-end product with the feature you needed. That's what "product differentiation" means.

The US engineer still costs more than the Chinese engineer. Low end products can't compete. You'd rather they lose money on each box...

Reply to
krw

buys

letting

You're certainly a lot quicker to judge others' actions than I. A few trees and $.05 parts is still a lot different than publishing the phone numbers of the design teams.

Sometimes. Not usually, though.

Sometimes a plan comes together but usually it's a huge waste of time. There is a reason for FAEs and Disties.

Reply to
krw

buys

letting

That's still a *very* different kettle-o-fish. They didn't send the developers out to teach Freshman EE classes.

Reply to
krw

when it

engineers. Big

LTC's

If you mean a full-bridge with integrated drivers I can't say, I never needed that from them.

I've seen too many line stop situations because of single-sourced parts. So I do care about that and often spend an extra few minutes to find a part that does have a 2nd source. My clients appreciate that. Some of the designs from my first consulting phase in the early 90's are still in production. For things like that 2nd source really matters.

OTOH I do get the occasional design-out gig because someone plopped down a few Maxim parts and then they couldn't deliver, so single source does have its upsides :-)

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

when it

engineers. Big

LTC's

No, four-phase synchronous switch (+external clock) for a 25V output.

But there are already scores of them already. Again, I won't lose sleep over one more.

So does Maxim, I suppose. ;-) Although I do have a Maxim part (x3) in my latest creation. Not my choice, though.

Reply to
krw

when it

engineers. Big

afford LTC's

Sounds like a boutique market but I am not familiar with those.

The purchasing manager might, some day, and then the phone rings ...

At least then they can't blame you :-)

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

they

blame the

Well, yeah, I am certainly not going to pay $5k when I get the same specs for well under $2k elsewhere. I'd have paid 20-25% more but not

150% more. They can "differentiate" all they want, to me that is one of the hardcore marketing screw-ups. Unfortunately US workers pay for those, via a lack or loss of jobs.

My clients are a bit smarter in that respect, they put all the features into the product that their customers expect. That way, their lunch isn't being eaten like it is right now WRT lab equipment.

I vividly remember when car manufacturers tried this stupid "product differentiation". "Oh, you want a steering wheel? That'll be extra. Do you also wish to purchase the optional spare tire?". Long story short they lost their short over that because Japanese cars call with everything included. Plus were more reliable.

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

buys

letting

Where did I say that? Support means documents (in the old days databooks), samples and most of all getting answers. If that requires an inquiry with the IC designers then that needs to happen. If not it's cased closed. A sad example was a company that didn't want to send me samples despite me offering my credit card for shipping, and whatever else they needed in reimbursement. They lost the business, I went with a competitor that did offer proper support.

Well, the good ones that perform research do.

It's perfectly ok to have FAEs as a first contact. Same for disties, Arrow is really good for example. You can't have everyone and their brother call the IC designers directly and I'd never ask for such a phone number, but was given it at times. That's how LTC does it as well. But those have to be smart engineers (in LTC's case they are) and they have to have access to the guys at the factory and in engineering. Else the chance of their products getting into cutting edge designs would become slim.

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

and when it

engineers. Big

afford LTC's

that

Not your simple switcher but I wouldn't call it exactly "boutique".

gate

at

That's going to happen anyway. There are just too many single-source parts now. How many multi-sourced CPUs are around these days?

The guys I work with (that have been in their jobs some time) like Maxim and actually pick on my for going elsewhere. Different experiences. go figure. ;-)

Reply to
krw

they

costs

blame the

or

Those jobs are *gone*. The question is how long the companies mak^h^h^hselling these things can stay alive.

Features can be cloned a lot faster than they can be created.

The last statement is the root of it. The "differentiated" products came with pre-installed rust (not that the Japanese didn't have their problems).

Reply to
krw

who buys

letting

from

You've been arguing for accessibility to the design teams.

That wasn't what we were discussing. I agreed that collateral should be readily available and it mostly is (I do hate having to "log in" to see a datasheet, too).

What company is that? I've been getting samples in the hundreds (unit-logic to high-end DSPs) and even tens of thousands (capacitors). I did have to buy one boost switcher (from Avnet) because no one else had them, even the manufacturer. The bitch is that I had to buy the whole damned reel. :-(

Like that stuff posted here from MIT once in a while? ;-) Unless they're paired up with major corporations, universities are mostly out of the loop anymore. The equipment is just too expensive.

That's exactly what I've been saying. ...and you've been arguing against!

That's exactly what I've been saying. I can't afford LTC because they *do* provide that service for everyone, and charge everyone for it. I'd be shot if I designed in a LTC part.

Nonsense.

Reply to
krw

Have you tried to get a full Marvell datasheet recently?

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Reply to
Spehro Pefhany

Quite a few. Now you know why I prefer the 8051 architecture :-)

Well, when it hits the fan you can say "Told ya so". As a consultant, I cannot do that :-)

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

they

costs

blame the

or

shifting

Yes. That is exactly what Steve Jobs told our president. Whether Washingtion really listens is another questions and sometimes I believe they don't. But the EE jobs don't have to go, those are mostly the responsibility of the companies.

Oh, they'll stay alive for a long time. But the danger is that they gradually become a glorified sales outlet for overseas products.

But not by the end customer. If they ain't in there and I need them then I ain't buying.

Oh yeah, I had a Chrysler that was almost gone from corrosion in about six years. That was my last one, they've lost a customer for life. After that I bought a German car which is now 25 and according to the current owner still has no rust. I now drive a Japanese car which after 15 years looks and rides like new. Not even the dome light dared to blow a bulb.

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

who buys

letting

that

from

I never argued for direct access. The FAEs need to be able to pull info from them in due time, the IC design managers must allow their staff time for such support activity. If they don't they make a grave mistake.

To me this includes answers from the IC designers in due time, that's what I mean with "getting answers".

Infineon. But meantime they've become better.

I can hardly convince a client to buy a reel for $3k when I need 1-2 parts to test something. Then I walk and pick the next mfg who will send samples.

In medical ultrasound universities still do good research. Don't know about MIT though, what came from their press guys was sometimes a bit embarrassing.

I am not. I do not care how this access happens as long as it is _quick_ and thorough.

Well, if you'd design mission-critical stuff you'd almost have to. Because their parts can be simulated much better than most anything else. Some mfgs don't offer SPICE models at all.

It is absolutely the truth. Seen it happen times and again.

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

over

...and NONE of them are multi-sourced. They have unique peripherals, packages/pinouts. You might just as well claim ARMs are all the same.

No, you hit the jackpot. I work overtime, for nothing.

Reply to
krw

(because they

costs

blame the

technical or

the

up.

the

shifting

The magnitude is different (not as cost sensitive) but the same problems exist.

That's the way they stay alive. However, they add overhead. If there is no value add, they won't last long that way either.

products

The Asian competition can. ...and will.

I had a '74 Ford that was just about gone after three years. A snow plow finished it off but gravity was going to do the job soon enough. I also had a '78 Ford that lasted 14 years (140K mi). The door-dings had rusted through but it still ran great and the engine (250CID straight six) had never had so much as its valve covers off. The later US cars are far better, though one of my minivans had serious rust after 10 years but it was just short of totaled when at six-months.

Bottom line, the domestic cars are far better than they were thirty years ago. I've never seen a foreign car I'd pay for. I came close with the pick-up, though.

Reply to
krw

Not since IBM. No problem then.

Reply to
krw

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