[10SNE1]

Ran across this while researching PS design.

Anyone evaluated this as a means of creating dual 9 volt rails from a single 9v battery?

Using low ESR caps and the frequency boost option of the MAX1044 device, it looks as if you could get dual 9 volt with any ripple in the inaudible range.

Charge Pump Converter link

 

[10SNE1]

Further rambling on the web, I note also a sister product - the Max860 which can take up to 5.5v supply and provide (+) & (-) rails at that voltage at up to 50ma.

Since it also can run at inaudible switching frequency, it might be usable to run the CMOY design using 3*1.5v alkaline or 4*1.25 nimh cells.

I plan to noodle with this but it will be a low priority for now.

MAX860 data

 

[guzzler]

interesting! quite a lot of passives to add, but still a lot less than two 9V batteries. BUT they only provide 10mA out, so they would have to be buffered, but because it would effectively be below the supply rails, you can't do that...

damn, could have been useful!!

g

edit: dammit, beat me to it on the reply!

 

[10SNE1]

Well, I found yet another link that sheds more light on the ins and outs of this approach.

Worth a read.

The ins and outs of charge-pump-converter ICs

 

[stsski14]

Check out the Max660.  Apparently it can dump out 100ma at rated voltage.  I think I might order a few to do some testing.

 

[jcx]

hard to get higher current and higher V together in available chips
 
the "best" application for sw C chips is supply splitting - making a low Z gnd for your 9-12V single supply since the lower V parts handle the current
 
much more efficient than "active gnd"
 
for doubling 9V at more than 10-20 mA inductive switched supplies are good but not common hobbyist designs