PWM injector driver

[Carter Shore]

Hello listers,
A while back I worked on some swedish (SAAB-Scania)
printers that used a capacitor voltage doubler circuit
to do peak/hold for the print solenoid driver.
The capacitor was switched in series with the supply
voltage to supply 2X voltage when the solenoid fired,
then it decayed to 1X voltage for the remainder of the
firing event.
These drivers were remarkably reliable, the circuit
was dead simple, and used good quality film capacitors
of a few microfarads, along with a couple of diodes to
implement the doubler.

I bet I could dig up the schematics and scan them if
anyone is interested.

(clever, those Swedish engineers)

Carter Shore

>He said *switching power supply* <beavis>.
>Doc just leaft the room looking to see if it's
menitoned in any of 
Forrest
>Mimms stuff.
>
>> Also pondering on a diode in series with the
injector, then apply 
reverse
>> voltage when time to close, just to collapse the
field/stop the 
current,
>> not to do an actual reverse current.
>> Thoughts???
>
>What I'd like to do is run em on 24v, for opening,
min V for On, and 
then
>off.
>Bruce


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