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PWM Hit And Hold Solenoid Driver Using CD4093

Overview Reviews (2)

To minimize solenoid power, a full voltage initial pulse can be applied until the solenoid pulls in, then a lower voltage applied to maintain the position. This can be done by switching in a series resistor, but that wastes power. A more...

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Author: crutschow

Views: 12,558

First release: Nov 2, 2020

Last update: Nov 2, 2020

Rating: 4.50 star(s) 2 ratings

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Latest reviews

Fady_18
5.00 star(s)
Apr 9, 2023

Hello Crutschow,
I think this PWM hit and hold is brilliant using CD4093. I actually have a small application were I need the PWM hit and hold for a 2 Amp solenoid. The solenoid application needs a bit longer delay, so I changed the R and C values to be 22UF instead of 510nf. I have tried the circuit with IRF44z and it worked great. But now I am trying a smaller version with the 4466 mosfet and it simply never goes to the PWM mode. I really do not know what went wrong and I would really appreciate your help. If there is a way to communicate with you to show you the pcb schematics, I would truly appreciate it. My email is: fadyeng18@gmail.com

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keyboards
4.00 star(s)
May 23, 2021

Certainly a different way of doing it, but it has been patented.
I was a co-author of a patent (#4,797,779) back in the late 80's that did exactly the same thing with lock solenoids for the company I was working for at the time (Folger-Adam Co.). My design used an LM556 (dual 555 timer) to make it happen. We did use an intermittent duty DC solenoid at full current @ 0.2 Hz and maintained hold with a PWM at 16KHz. Both duty cycles were around 20%
Being that it was used in a security type function, the initial full current pulse was re-applied every couple of seconds to make sure the solenoid was properly seated.

crutschow

Is that patent now expired?

Certainly it can be done with a 556, but I believe this circuit is simpler and cheaper. :-)