Voltage regulator

[Raymond C Drouillard]

On Thu, 31 Dec 1998 09:47:34 -0500 Barry Tisdale <btisdale at cybersol.com>
writes:
>Any electronics gurus out there familiar w/ voltage boosters / 
>regulators?  There's a manufacturer out there specializing in 
>aftermarket parts for turbo cars that sells an adjustable voltage 
>regulator that will supply 12-16v (@ up to 40a) from a battery source 
>of 8-12v, to boost the stock fuel pump output.
>
>Any idea what circuitry is involved?  The price of this gadget is $250 
>or so, which probably means you could put it together for $50 (?).  If 
>the stock pump is not up to the needs of a hopped up engine, this 
>seems like a neat gadget.
>
>Barry
>

My understanding is that it is simply a switching voltage regulater -
much like the one in your computer.  In fact, you could probablly modify
a computer power supply to do the job.  You have to know what you're
doing, though.  A better plan might be to scam the parts from a stack of
old supplies and build it from scratch.

Switching power supplies have the unique feature of being able to step
the voltage up as well as down.  They are very efficient because there
are no inherent I2R losses.  There are losses because the components are
not perfect, but those losses are not inherent to the design, the way
they are with a standard power supply.

Radio Shack makes an excellent little book (like the Engineers'
Notebooks) that explains how they work.

Briefly:  A switching transister switchies a DC voltage on and off
through an inducter to the load.  There is a diode across the transister
to allow current to flow from the "return" line when the transister is
switched off.  The inducter stores energy when the transister is switched
on, and supplies it when the transister is switched off.  Switching
speeds are generally in the kilohertz (or higher) range.  A higher
switching speed allows the use of a smaller incucter.

It is the switching power supply that generates most of the RF noise in a
computer.

Ray Drouillard, BSEE

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