what's your favourite boost regulator?

[darron]

this is something that i've been researching for years but have never found a solution that seemed simple AND good.


i want a boost regulator to deliver around 15-18VDC so that I can play with higher voltages from 9V in pedals. I've noticed how the sound can open up so much more going from just 9V to 12V...


there's a lot out there... not many in a through hole package... and not many which are well spec'd for audio. IE they might be great for driving LEDs or a motor... some switch at a audio frequencies too.
current required is minimal... just a few transistors etc. (:



advice from someone with experience would be much better than difficult experimentation of my own.... failing that i'd even like to try something like transistor oscillator > transformer > regulator                   or... voltage tripler and then regulator.




not a massive debate, but i'm hoping someone can point me to one i haven't looked at yet (:


cheers!

[geertjacobs]

http://www.geofex.com/circuits/+9_to_33.htm

[darron]

http://www.geofex.com/circuits/+9_to_33.htm

i'm after a regulated boost though... this would only work if i used it as a tripler and then had a regulator following it. i've seen pedals with noise issues using the MAX1044 too, even with the higher frequency switch shorted. i know there's a heap of boost ICs out there but I'm looking for the most suitable one.


i'f i'm going to go through the work of using a MAX1044 and regulator i'd probably rather build an oscillator instead. a chip in some pedals would not look cool too!

[R.G.]

I believe the LT1054 has a built in regulation function. Never used it, just remember from the data sheet.

There are a number of regulated boost chips not requiring external transistors that use inductances. Check power management ICs at TI.com.

[darron]

i saw the LT1054 on the small bear website so i thought it might be something that the forum members commonly use. searching found quite a bit of talk but not too much action, especially not in the regulated mode.

i wouldn't mind putting a small inductor on. from what i saw all of the quieter switching ones used an inductor. the ones that i liked i'd have to bight the bullet i think and go smd though... sigh...



MAX1044 might be the way. but i'd have to triple the voltage pretty much to regulate down to +17V or so. the current draw is tiny so i think most regulators should still be happy with that much differential... could i run the MAX1044 into a step-up transformer instead of a doubler network and what noise implications might that have? also, which frequency mode would be suggested?

glad i don't feel silly now that people aren't jumping in yet and saying "dah! use TI's xxxx chip!"

[darron]

thanks for posting the terrific article R.G.

i ended up using the max1044 through two doubler stages and then a fixed 18v regulator. the footprint on the pcb will be pretty big, but i'm not expecting any stability problems. decided to go with something more traditional to our DIY than a little SMD switch mode inductor chip.


what value caps do people usually use on the MAX? i first tried 1uF MKTs and am now using 22uF low ESR electros. i try to avoid electros generally now though. haven't plugged it into the scope yet to see what the ripple looks like....

would 100uF be a better idea? they usually have a similar footprint and cost anyway.... or...?