[Milsurplus] 12 to 24 volt conversion, the issue of cost

[Jim Whartenby]

You PWM a NE555 using pin 5 which connects to the top junction of the three 5k ohm resistors used to set the limits of the voltage comparators.

The 555 should make a usable PWM for the step up converter.
Jim

--- On Thu, 10/8/09, Tom Dawson <wb3akd at earthlink.net> wrote:

> On your DC-DC converter project, I might recommend that you
> investigate boost converters as the inductors are a single
> winding.  I've made 
> experimental converters with just a 555 driving the switch transistor. 
> Regulation is achieved via adjusting the duty cycle
> (something other than a 
> 555 is needed if you want to regulate this way, but the 555
> is a good place 
> to start).  National semiconductor has application
> which greatly notes on 
> their controller chips and boost  supplies in
> general.
>