[dorkbotpdx-blabber] 12 volt 20 amp power supply to drive a couple of pumps

[Paul Stoffregen]

> I'm getting a 24V line at
> ~20 amps. I need to take this down to a 12 volt line and current limit it so
> that I don't burn up my pumps.

Maybe if you drive the motors with PWM right from the 24 volt line, 
averaging about 50%, you can avoid needing to regulate down to 12 
volts?  Then all you need is a big MOSFET, probably rated for 40 volts 
or 50 volts, and a lot of current, and probably a special driver chip to 
drive its gate quickly.

Of course, some sort of current sensing to control the PWM can also 
implement the current limiting, rather than needing expensive 
circuitry... maube?