[SOLVED] How to have the correct hysteresis

[houly]

Hello

I would want to evaluate the value of R2 and Vref in order to have an hysteresis voltage of 0.1V and a threshold- of 2.45V.

here is the schematic :





So I apply
VH=R1/(R1+R2)*Vsat+

And

VTH-=R2/(R1+R2)*VREF
Because VSAT-=0V.

Fo the reference voltage I have 2.485V and for R2=695.399k. When I simulate the stage, I have about132mV for the hysteresis… Could you help me to explain it ?

Regards

 

[barry]

I simulated this with LTspice (which is what it looked like you did) and I got about 106mV of hysteresis. Maybe you don't hav your cursors place accurately? zoom in...

 

[houly]

Hello Barry,
So sorry, you're right, I have the same result as you.