Hi Harold,

Thinking about this, using a standard buck converter topology but with
feedback from the input rather than output, the feedback signal would
need to be inverted, so as to reduce duty cycle when the voltage is low.

This would be easy to do with an old-fashioned switchmode IC that has
all the pins available. But with a 5 terminal all-in-one part like the
XL6009 it might require more parts.

Compensation might need to be tinkered with as well.

I need to stop thinking about this, I want to experiment with it but I
have work to do :-)

Best regards, Bob


> On 2/23/15, Harold Hallikainen <harold@hallikainen.org> wrote:
> > One clever thing I learned from Linear Technology is that the maximum
> > power point is very close to a constant voltage out of a solar panel. S=
o,
> > a very simple MPPT converter is a constant voltage converter where you
> > take the feedback from the INPUT instead of the output. The switcher
> > adjusts the duty cycle as required to keep the input voltage constant.
> >
> > Harold

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