Use of Schottky Diode in an Overvoltage Protection Circuit

Thread Starter

meteturedi

Joined Oct 24, 2017
3
Greetings,

Can someone please explain to me what the use of D500 in the below schematic is? I understand how the circuit behaves under overvoltage condition and shutdown condition but cant find the purpose of Schottky is.

upload_2017-10-24_11-27-25.png


Best Regards,
Mete
 

crutschow

Joined Mar 14, 2008
26,007
I am puzzled also. :confused:
I don't see an obvious reason for the diode.
If Q1B turns on it would apply voltage to the collector of Q1A if there were no diode, but that would not hurt the transistor.
 

Thread Starter

meteturedi

Joined Oct 24, 2017
3
Okay okay okay. That was my bad. Now I see. There is another conenction to OVPROT_5VC as such;

upload_2017-10-25_8-56-53.png


So we do not want this LED to be ON when switch is moved to SHUTDOWN position. That's why we isoalate 5VE from 5VC I assume, right?

Sorry for taking your time.

Regards,
Mete
 
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