Hi all,

I have the next circuit to conform a signal reset which is a low state signal, I do that pressing SW1.



Now, I would like to conform the signal reset when an external 12V signal comes, I would like to do that with a more elegant solution than using a relé or an optocoupler.

some idea to do that simple and easy?

thank you all

 

use a voltage divider and clamp output to vdd to protect input.
From 12V to 2.5 take 10K and 2.4K ==> 1 mA approx
center 10K & 2.4 clamp via fast diode to vdd.
if however the system can't handle currents (Via 10K) higher than 1 mA then take 100K and 24K but you have to change C51 ( to get the correct rc time).

Picbuster

 

Here's my offering :-

R4 limits the cap discharge current through the switch.

 

Here's my offering :-
View attachment 174744
R4 limits the cap discharge current through the switch.

ohh really elegant!

thanks

 

Hi all,

I have the next circuit to conform a signal reset which is a low state signal, I do that pressing SW1.

View attachment 174729

Now, I would like to conform the signal reset when an external 12V signal comes, I would like to do that with a more elegant solution than using a relé or an optocoupler.

some idea to do that simple and easy?

thank you all

This should work (or function).
Picbuster