[sdiy] controlling VCO with guitar

[Harry Bissell]

lol (DESIGNING WITH CHARGE PUMPS TODAY)

Most charge pumps have about a 6V max input, so doubling a 9V might be tricky. If you did double, and invert negative you
could get roughly +/- 18V (unregulated) at light currents. Possibly you could use an LDO regulator to get +/-15. As you are switching
anyway you might be better off with an inductor based solution. 

Capacitors will have high inrush currents (think spikes) and inductors will have lots of noise when they switch off (think spikes). 
Hey, its a switching regulator either way...

H^) harry



----- Original Message -----
From: ASSI <Stromeko at nexgo.de>
To: synth-diy at dropmix.xs4all.nl
Sent: Thu, 20 Jan 2011 11:35:28 -0500 (EST)
Subject: Re: [sdiy] controlling VCO with guitar

On Thursday 20 January 2011, Paul Perry wrote:
> It's not trivial to get +-15v with charge pumps - check the input voltage
> ratings on the cheap pumps.

Not sure what you mean by charge pumps (the only ones I know that are true 
charge pumps are for TTL->RS232, e.g. from Maxim), but you'd have a hard 
time drawing much curent from one of those.  There are however inductor 
based DC/DC converters that have +-12V and +-15V output.  Traco has some 
isolated ones with 4:1 range input starting from 4.5V that are rated 3W, for 
instance.  Ripple voltage is something to look out for, so you might need to 
follow with a pair of linear regulators to clean up.


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Samples for the Waldorf Blofeld:
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Harry Bissell & Nora Abdullah 4eva