step-up circuit

[jacob.zurasky]

Hello all! I am looking for some info regarding a step-up circuit. I need to boost 3v up to 12v (or any inbetween as well). I have seen some simple circuits with an inductor connected to the positive supply with the other end of the inductor being pulled low with a transitor being switched on. While the transistor switched off, it supplies the boosted voltage after going through a diode and capacitor. Im guessing switching frequency and inductor value relate to voltage boost, but I cant seem to find any good info. Any advice or pointing me in the right direction would be a great help. The current draw of the load will be very low at the boosted side ( probably < 25ma). -Jacob

Edit: Just found the SEPIC wikipedia page with loads of info, but any advice would still be appriciated! Thanks

 

[Nigel Goodwin]

Check this months (June) EPE magazine, they have just what you need - a converter based on a TL499A, input 3V, output adjustable from 4.5V to 20V.

You can buy it as a kit from **broken link removed** search for order code kc5391

 

[jacob.zurasky]

Thanks Nigel for always having an answer

 

[Papabravo]

SwitcherCAD III/LTSpice will take your input and output requirements for voltage and current, give you a selections of designs with component values, and simulate the thing for you. Could hardly be easier.

 

[bananasiong]

SwitcherCAD III/LTSpice will take your input and output requirements for voltage and current, give you a selections of designs with component values, and simulate the thing for you. Could hardly be easier.

I didn't know that the simulator can be used in this way..
But I can see most of the voltage booster IC available in LTSpice are from Linear Tech.

Check this months (June) EPE magazine, they have just what you need - a converter based on a TL499A, input 3V, output adjustable from 4.5V to 20V.

Is June EPE released? This magazine is quite costly over here

 

[Sceadwian]

Funny =) The main reason Switcher Cad exists (and explaining it's name) is for develeopment of Linear Tech's entire line of switch mode IC's.

 

[bananasiong]

Funny =) The main reason Switcher Cad exists (and explaining it's name) is for develeopment of Linear Tech's entire line of switch mode IC's.

Ya, that's right..

 

[Nigel Goodwin]

Thanks Nigel for always having an answer

By some happy coincidence my subscription issue came in the post yesterday morning, so it was fresh in my mind!

bananasiong - EPE always comes out a month before the date on the cover, and always has. To lower the cost you can subscribe to an on-line PDF version.

 

[audioguru]

Usually a kit has its installation manual available online complete with its schematic and parts list.

But the Jaycar KC5391 kit doesn't seem to be available anymore.

 

[Nigel Goodwin]

Usually a kit has its installation manual available online complete with its schematic and parts list.

But the Jaycar KC5391 kit doesn't seem to be available anymore.

It's still listed on the website I posted, and it's advertised in Jaycars advert in the EPE issue.

 

[audioguru]

"Not all products are available in all countries". Jaycar knows I'm in Canada.

The kc5391 kit was not in their numerical sequence for kits but a search found it. It is the "Never buy a 9V Battery Again" project from Silicon Chip magazine a couple of years ago.

 

[Nigel Goodwin]

"Not all products are available in all countries". Jaycar knows I'm in Canada.

Well that doesn't mean it's no longer available?.

The kc5391 kit was not in their numerical sequence for kits but a search found it. It is the "Never buy a 9V Battery Again" project from Silicon Chip magazine a couple of years ago.

Yes, it said so in the article in EPE, they appear to be reprinting a LOT of Silicon Chip articles recently.

 

[Hero999]

 

[things]

if anyone wants to see the "never buy a 9 volt battery again" curcuit just let me know and i'll post it for you to see . i made one today

 

[Hero999]

Why don't you post it on the forum for all of us to see?

 

[Nigel Goodwin]

Why don't you post it on the forum for all of us to see?

Probably because it's a copyrighted circuit from a current magazine issue?.

 

[Sceadwian]

Check applicable fair use laws, often posting something like that for reference is perfectly legal.

 

[Nigel Goodwin]

Check applicable fair use laws, often posting something like that for reference is perfectly legal.

Perhaps that's some obscure American term?, never heard of it - but I don't see as publishing copyrighted material on the net is legal in any sensible country (I know some countries don't respect copyright or patents).

 

[Hero999]

It's called fair deal here in the UK.

It means that you can include small amounts or copyrighted material in a book or scientific paper providing it's referenced and it's small compared to the work you're producing. Fair deal is here as a means to protect free speech, for example it allows you to include a quote or graph from a book or a screen shot from a computer program without commiting copyright infringement.

I don't know how this works as far as posting things on forums. I imagine there is a differenct between posting a picture or a small extract from a paper to the entire PDF.

 

[things]

all right i'll get the circuit diagram and post it, should i post it in the projects forum or here?
it should be legal because all it is is referance,not for big companies or whatever to put into mass production, most circuits are copyrighted and i see them posted here everywhere?

Post deleted! - the circuit is copyrighted from a CURRENT magazine. Posting such a circuit here is putting the board at risk!. It certainly ISN'T legal to post it!.

Moderator.