Voltage doubler with MAX1044

[jrc4558]

Good day to you all!
I have examined the datasheet for MAX1044 and failed to find the ratings for the maximum current this chip can provide. I'm looking to create a separate power supply (18-27volts) for the booster-distortion part of my pedalboard and so far, I will need around 100mA. And at least 50mA bi-polar. Now the question, how many chips will I fry before I get it to work? lol
The real question is, how much current can the MAX 1044 chip provide in the bipolar configuration and in 18-27 voltage doubler/tripler configurations.
Thank you!

[R.G.]

The MAX1044 data sheets *do* mention the equivalent series resistance - about 80 ohms if my memory is correct, but check the data sheet for the actual value. I don't think you'll fry the device, but your voltage will sag a lot as you overload it. The datasheet and/or application notes show you how to use them in series/parallel for both more voltage and more current.

My personal preference would be to provide a single MAX1044 inside each pedal circuit that needs it, not one or a few per pedalboard. But that's just me.

[MartyMart]

I built one to supply 18 volts.
I was under the impression that no more than 40-60Ma was about
all this thing can supply, but ..... It did power a "Mutron III" which pulls
about 120-150Ma !
The "battery fail" light kept coming on, so that's a no-no.
There are more powerful chips available, or use one per pedal as RG
suggests.
BTW:
It works well with my Ibanez FL301 and a few other 18 volters .... one at
a time of course !!

Marty.

[Sir H C]

Since the output resistance is directly related to the supply voltage and they don't have anything talking about Rout with 10v supply, you have to go to the graphs on the data sheet.  

http://pdfserv.maxim-ic.com/en/ds/ICL7660-MAX1044.pdf

On page 3, upper right corner it shows a 1 volt drop for 40 mA output current.  This dropout is pretty linear (set by the ESR of the caps and the Rds ons of the switching devices) and so you can then calculate your drop for larger currents accordingly.

Realize too that you will be wasting more heat in the chip so therefore you could start to overstress the chip and have them die.  

Finally, these chips have pretty low oscillator frequencies.  You have to deal with the fact that your oscillator will be noise in the system.

Usually if you want more than 100mA or so you have to go to an inductor based system which are a lot more complex but can get the voltages and currents you desire with regulation.

[markusw]

The LT1054 allows up to 15V input voltage and has about 1-1.5V loss at 100 mA.  Oscillator freq can be raised by adding an extra cap. Maybe worth a try.

Markus

[Xaar]

The MAX1044 data sheets *do* mention the equivalent series resistance - about 80 ohms if my memory is correct, but check the data sheet for the actual value. I don't think you'll fry the device, but your voltage will sag a lot as you overload it. The datasheet and/or application notes show you how to use them in series/parallel for both more voltage and more current.

My personal preference would be to provide a single MAX1044 inside each pedal circuit that needs it, not one or a few per pedalboard. But that's just me.

RG KEen, I need to supply one preamp project with : +/-15V (for opamps) and one +24V (for JFETs) . All coming from one 9V battery.

Should I supply the pcb with ONE  MAX1044 circuit mixing both ideas of your schematic "higher voltage from a 9V battery" with the schematic of bipolar supply from 9v battery given by tonepad (or gaussmarkov) ?
I mean one  circuit yielding +/-15V (or +/-17V it's not important) and adding the necessary caps and schottkys to get +25 V from the +15 output? So I would get everything from one chip...
(Of course for the bipolar 17V I would have to add the necessary caps and schottkys connected to  pin5 of max1044 and to the ground)

Or.... is it more advisable to have 2 seperate supply circuits in parallel, each one with a max1044 chip? I mean one circuit yielding +/-17V and then  connecting the higher voltage circuit input DIRECTLY to the +9V battery to get +25V ?

One max1044 circuit to do the job or 2 separate supply circuits ?

Sorry if it sounds stupid. By the way the preamp project is a Randall X2 "fry" channel.