Review this Goofy 555 Based SMPS Design

I'm making changes frequently and updating the schematic. Best to check link prior to posting... D from BC

You need to spend more time at the pub me thinks.

'Hey bub, How they fishing?'

'Well, I have my bait back.'

'Mind if I move your book?'

'No, go ahead.'

'Hmmm. Warhol. Interesting bait you've got their son. Colors are trying but the bent clock stuff don't fit.'

'But you can see where.....'

'Mind if I flush?'

'No, go ahead.'

'S'OK, see we take your shit out the cistern and we push this here handle and, ......... Hey! My shit disappears.'

'Great, I don't suppose you could...'

'No problem son, I'll just put the seat back down and put your book on it, page 24? There you go. Cistern's filling up so get ready to cast again'.

DNA

Swimming with Sharks

Good movie :) D from BC

Well...I think this post flopped... Dunno if I should update the file on my site.. I'm still learning the newsgroup culture...so I probably goofed.

I'll take some guesses as to few responses:

*Posting a URL is a security risk *Large loopy circuits are too much to review *Not much interest in smps control *Poor post title *Circuit is too amateur *Nothing new ..seen it before..boring..bunch of app notes stuck together *The cct is so complicated..I can figure it out myself *No specific questions posted

• Everybody is out having fun :) D from BC

You forgot: Really ugly schematic: Poor layout. Lousy contrast. Uninformative explanation of your logic and thinking.

-- Joe Legris

You didn't post the text .asc file that we load directly into LTspice so we could play with the circuit without rebuilding it from scratch. Why do you think anyone would invest a couple hours retracing your modeling effort, just to see that the circuit operates?

Wow! Somebody is actually interested :)..... Usually I don't focus on schematic neatness when I'm developing a cct.. Too many changes happening.. I'll try to straighten it out a bit for presentation. Lousy contrast? Switch to black background and have white lines?

I'll write up "why" this and that description on the site.. Will be posting updated URL shortly.. Thanks D from BC

Ahhh...I guess LTspice graphics are easy to spot... :) k....I'll include .asc download link on site.. Also, any missing models. Will be updating site soon..look for post later on.. Thanks D from BC

The main advantages of providing the .asc file is that not only can we see exactly what you can see about how every part of your circuit operates (or is modeled to operate) we can give back working examples of suggestions for changes in the circuit and even the layout of the schematic that you can instantly use. You might also join the Yahoo discussion group dedicated to LTspice, where there is a lot of LTspice expertise on line.

No, it's something else - I'm using a Mac and your PDF comes out as very pale grey lines on a white background. How are you generating the schematic?

[snip]

Looks great at my end.. I'm using Adobe to create PDF's. I'll be uploading JPEG and SwitcherCADIII files sometime today.. D from BC

Looks Bad in the sense that Bad does not mean Good. However, not an excuse to stereotype the atypical. I give you 'Species' and the part when her titty nipples descend to strangle the 'hero' of the filum.

DNA

The ironic thing is LTSpice SwitchercadIII was probably made to sell LT controllers but I'm controlling with cheapo 555's instead.

Links: JPG schematic on:

ASC. SwitcherCADIII file on:

PDF on:

I've included notes for many parts in the PDF. Might be reader version dependent.

This is my current project that I'm improving and developing. I'll be interested in any comments, helpful tips and design improvements.

D from BC

Note: FMMT596 transistor model info is in the PDF file. Put mouse on note icon. Cut and paste in SwitcherCADIII standard.bjt file.. Or sub in a good 200V rated xsistor for simulation.

Currently thinking about:

*Selecting a good MOS for M3 and catch diode for D2. *I don't trust that high side current sensing cct... don't know why..however looks good on sim.

• Limit bandwidth on U2 op amp? D from BC

Dell used to roll their own Dc/DC converters with 555s. Well, the key phrase is "used to."

Do you know if it was hysteretic or PWM? I recall seeing an app note one time for turning the 555 into a PWM. D from BC

I reverse engineered the smps from a nintendo gameboy once. very cute buck converter based around an HC14 (which is now my preferred PWM contoller)

Cheers Terry

Neat... Guess all to keep costs down.. That's the schmitt inverter...right?

I picked CMOS 555..just because it had that cool parallel processing look to it. Also.... it's one of the most ancient IC's and a text book item. Using it in the cct. has an artistic quality. :)

D from BC