Protection voltage generating circuit with monotonic and stable power supply voltage behavior

A circuit 20 and method for generating a protection voltage includes a pair of voltage generating circuits 32A, 32B that generate voltages from the power supply voltage. The voltages have a differing dependence on the power supply voltage so that a difference between the first voltage and the second voltage changes sign for a particular value of the power supply voltage. The voltages are supplied to a protection voltage generating circuit 30 that includes a pair of amplifiers A10A, A10B having inputs that receive a respective one of the voltages and each of the amplifiers provides negative feedback to the other. An output circuit generates the protection voltage according to a maximum or a minimum value among the amplifier outputs, so that the protection voltage is monotonic and stable with respect to variation of the power supply voltage.