Mark Skeels wrote:
>
> > > Silicon Chip magazine December 2000 did a single cell to white LED
> > > converter. This uses 4 transistors and could use less. They use a basic
> > > cross coupled astable multivibrator driving a buffer which drives the
> pulsed
> > > coil.
>
> I used a astable multivibrator to drive a voltage doubler circuit. I had to
> add a JFET as a buffer to the output because it drew too much current and
> messed up the duty cycle.
>
> But, I'm thinking of going to some sort of inverting logic gate oscillator
> because it costs us about $.06 to put down each smt component.
>
> There were 10 components for the multivibrator and JFET buffer in the
> original design. I think I could use a hex inverter and parallel the left
> over inverters at the output, like, say, a 4049. I'd use this to drive the
> doubler network. I need to generate roughly 5 or 6 mA at the output. It runs
> at about 10KHz; the frequency and voltage outputs are not critical.
>
> Of course, this is unregulated. I needed it to generate a higher dc voltage
> to drive an op amp driving P-channel fets so that I could turn them off all
> of the way.

Hi Mark, this is interesting, using a hex inverter
or other logic chip, but surely this will be limited
to applications that step up from 5v to higher voltages?
Not for 1.1v to 5v application?
-Roman

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