CMOS Schmitt Trigger Circuit with Controllable Hysteresis Using Logical Threshold Voltage Control Circuit

A simple logical threshold voltage control circuit is proposed. It can be implemented using normal conventional CMOS inverters. The proposed circuit is able to control a logical threshold voltage of a gate linearly and continuously over a range of a power supply voltage. Applications to the Schmitt trigger circuit with controllable hysteresis and a window comparator are shown to demonstrate practical usages of the proposed circuit.