Non-inverting Op-amp Comparator with Hysteresis

[Jwillis]

How do I work out the Hysteresis of a comparator with a dynamic reference ?Do I just take an arbitrary reference voltage within the range I'm using and work it out from that? I'm not sure if the Vth (High Threshold Voltage) and Vtl (Low Threshold Voltage) should move up and down with the reference.

[David Hess]

The hysteresis is independent of the reference voltage unless specifically designed otherwise.  Usually it only depends on the output voltage swing and divider ratio.