On Tue, 17 Jan 2012 08:45:17 -0700, Jim Thompson
wrote:

On Tue, 17 Jan 2012 07:25:05 -0800, John Larkin
wrote:

On Tue, 17 Jan 2012 08:01:29 -0700, Jim Thompson
wrote:

[snip]

Naturally you will now show us your stupendous solution ?:-)

...Jim Thompson

Sure, why not?

ftp://jjlarkin.lmi.net/Hub_Alt_1.JPG

The step-down transformer gives the roughly 2:1 power/current boost.
The SSR (could be a pfet) is controlled to charge the battery to its
happy voltage. The control circuit is powered from the generator, not
from the battery. We only need to sense the battery voltage, which
takes microamps, not a discharge issue.

This is simple and very rugged. It can be switched off for minimum
drag and the light can - special feature! - be turned on and off!

The control block is simple: regulator, UVLO, comparator to drive the
SSR. Transzorb for luck, like the way garlic keeps vampires away.

Of course there are no values yet. One has to agree on function and
architecture first.

Then why did you "diss" me when I immediately had a behavioral
switcher architecture RUNNING in SIMULATION?

Because it was a trivial theoretical cartoon, in fact just some
waveforms. And it was a variable-duty-cycle switcher, which is *not*
what you ultimately posted. In other words, it was all show but
useless to the discussion at hand.



You're just an asshole.


So, you have chosen whining over discussing electronics. I knew you
would.



Let the discussion (or the whining, if that's what you're good at)
begin.

John

I suggest that you recall that I said that the hub dynamo, at least as
we have a model for, doesn't give you the boost you claim.

Of course I recall it. You're probably wrong.

Nope. I'm right. I even said why. But you're too dense to
understand.

I don't recall you explaining why. Why?



What's the difference
here between a step-down transformer and a fixed-duty-cycle buck
switcher? Both allow the alternator to deliver more power by better
impedance-matching the load.

Significant.

Explain why.




But, indeed, the circuit you present cannot be challenged... as usual
it has no component types or values.

So challenge it on architecture and function. The things you got
wrong. There's no point in designing the little control block until we
agree on whather the overall concept is usable on a bicycle, in real
life. (Actually, it has one issue. See it?)

Whine or discuss. The world is watching.

John

Show component types and values. Otherwise "discussion" with you is a
total waste of time.

You posted a useless, defect-filled simulation of a dumb buck
switcher, with values, that would be useless if built and put on a
bicycle. You won't even discuss the things that a real product would
need.

You probably don't even ride a bicycle, so you wouldn't appreciate the
issues. Like the biggest problem with my proposed design.

Things like component selection, values, packaging, and cost can't be
sensibly discussed without a definition of the problem and an
architectural approach to solving it. Probably, as a contract linear
IC designer, you're not used to working at that level.

John