I try to implement an undervoltage lockout trigger, when the supply voltage falls below a threshold voltage. The trigger itself should activate a gate driver, when there is enough voltage and below the threshold, it should be deactivated. A hysteresis is really important to prevent switching the power on and off to the gate driver, which can lead to destruction.
A comparator is the solution for this and I decided to take a TLV7031(Here). I have a power supply of 48VDC and want to trigger the undervoltage lockout at around 31VDC with at least 4VDC hysteresis. My solution looks like this, but I am unsure, if this will work, since I don't use comparators a lot:
R35 can be ignored, this is only to permanently activate the comparator output. The trigger voltage is 1.65VDC, which is (180kOhm + 10kOhm) / 10kOhm times the voltage for the power supply, that means 31.35VDC. The hysteresis is 3.3VDC * Rb/Ra = 0.2245, which is on the power supply side an equivalent voltage of 4.26VDC.
Are my calculations correct?
Edit: I did a simulation with a different comparator (LT1716) and it seems to work. Is this a standard non-inverting Schmitt Trigger circuit for any comparator?