On Wed, 2007-05-30 at 03:07 -0700, Andrew Lentvorski wrote: > Christoph Maier wrote: > > > By sheer coincidence, I used a circuit to get enough voltage for a green > > LED from only 700mV as proof-of-concept for wine: > > http://www.kernel-panic.org/Members/cmaier/hamburger-lugnut-log/archive/2007/02/04/both-linuxes-emulate-windows-xp/ > > (by the way, Plone still doesn't work quite right, *&[EMAIL PROTECTED]) > > but you'd need an AC waveform for the charge pumps to work. > > It's not easy at all to build a DC to AC converter that works from > > 700mV. > > What do you mean by DC to AC converter? > > If all you need is to generate an AC waveform, MOSFET ring oscillators > work just fine at .7 V. They're a little slow by VLSI standards, but > probably faster than anything a home hobbyist is likely able to measure. > > If you need to actually boost the voltage, that's a different ball game. > You can probably do it with MOSFET's and passives if you try hard enough. > > However, Schottky or germanium diodes are probably an easier solution if > much lossier. > > -a
Schottky diodes is what I'm proposing. But to generate an AC waveform, you need to start with active devices, i.e., MOSFET switches. A MOSFET ring oscillator is straightforward at 700mV, a RAIL-TO-RAIL MOSFET oscillator that can source substantial current isn't. Christoph -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
