loose-electron wrote on Dec 7th, 2011, 9:34am:cktdesigner wrote on Dec 6th, 2011, 8:12pm:Thank you.
could you please tell which inverter's aspect ratio will need to be adjusted to modify upper and lower swtiching points?
INVBUF or INVFB?
You have 3 inverters in a "pulling" process here, the input device (drawn at the transistor level) and the other 2.
Your hysterisis is set by the relative geometry sizes of the input device and the feedback inverter.
Its voltage division with resistors and switches, draw each of the inverters as 2 switches and 2 resistors, and think of it that way. You will start to understand whats going on better at that point.
I am still unable to understand how hysterisis is present.
I do not understand how the higher switching point (VIH) occurs at a high voltage value and also in the return path why does the circuit switch at a lower level voltage.
Could you please point me to a source where operation of this circuit is explained in detail?
Thanks.