Today's noob question - voltage doublers: can they power more than one circuit?

[moid]

Hello everyone

Today's noob question: Would the below Voltage Doubler circuit be able to power two different circuits at 18v (assuming I put 9v in) or is it only capable of outputting 18v to one circuit at a time?


I suspect I need to build two of these, but I thought I'd ask before I start making them in case there was some secret voodoo tricknology that allowed them to do wondrous things! Thanks

[adrianhertz]

yes is possible to power up multiple circuits, the problem may be the current necessary to feed those circuits...

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[moid]

Thanks for the fast reply!

I was going to power two Mr Black Tiger Boosts



I guess it comes down to how much current the JRC4558 uses? I might be swapping that for an OPA2134 if it turns out to be louder than the 4558... If I only have to build one voltage doubler that will save me a lot of time and parts. I'll try with one and see how I get on then.

[Mark Hammer]

Charge pumps can power as many circuits as you want...as long as the current requirements for the various circuits don't exceed the capacity of the charge pump.  In some cases (e.g., fuzzes that draw 2ma) you could probably power a half dozen pedals from one.  In other cases, the current draw for a single pedal would exceed what most charge pump chips can provide.

[duck_arse]

if you was going to use a 555 as a charge pump, you'd want to be very particular about your ground and supply wirings, and you might still end up with tikking of some sort. the 555 is good for 200mA I think, but you don't get all that after doubling. also, you won't get exact 18V out with 9V in, there will be diode losses. one important point to note is the led current - you don't want the charge pumper (whatever type you use) supplying the led current, because it might be 10x or more the current drawn by the audio section. this might lead to problems with tikking and sag.

as Mark says, load em up till they don't supply any more. the 7555 might even provide enough current for two of your tigers.

add at least one 100nF ceramic/plcc cap across the supply line and one on the 18V out on that layout as well. (the upper 220uF cap appears to be on three spots, whilst the other two electros are on two - be warned! a circuit for?)

[antonis]

<the 555 is good for 200mA I think, but you don't get all that after doubling>

My good old down-under fellow forgets that you can use a series pass power transistor on NE555 output, with a cost of a V_BE forward voltage drop.. 

Don't bother Stephen...   
(I suddenly realized the need for a higher than 18V external PS..)

Will you ever forgive my naivety..?? 

[duck_arse]

I will, antonis, because I, myself, was thinking of saying switch a mosfet with the output for as much volts as you'd want, but decided better of it.