Binary inverter circuits with configurable threshold voltages

A method of inverting an input signal, comprising:

• receiving an input signal at an input of an inverter stage, the inverter stage including a first complementary pair of transistors connected in a push-pull configuration, wherein the input of the inverter stage is coupled to gates of the first complementary pair of transistors and an output of the inverter stage is coupled to drains of the first complementary pair of transistors;
• controlling a threshold voltage of the inverter stage with one or more first degeneration transistors coupled between a source of one of the first complementary pair of transistors and a power supply rail and a reference circuit having an output coupled to one or more gates of the one or more first degeneration transistors, wherein the reference circuit controls the one or more first degeneration transistors to cause the inverter stage to have a threshold voltage equal to a threshold control voltage;
• receiving the threshold control voltage at an input of the reference circuit, wherein the reference circuit comprises a second complementary pair of transistors connected in a push-pull configuration, and wherein the threshold control voltage is provided to gates of the second complementary pair of transistors;
• providing the output of the reference circuit from a connection coupled to drains of the second complementary pair of transistors;
• biasing the reference circuit with a bias voltage applied to a gate of a reference degeneration transistor coupled between a source of one of the second complementary pair of transistors and the power supply rail;
• and
• biasing the inverter stage with the bias voltage by applying the bias voltage to the one or more corresponding gates of the one or more first degeneration transistors.