Patent ID: 7042264

Claim:
A variable drive strength hysteresis input circuit comprising: pull-up circuitry having a pull-up drive strength; pull-down circuitry having a pull-down drive strength; and variable drive strength circuitry that is capable of changing at least one of: said pull-up drive strength of said pull-up circuitry and said pull-down drive strength of said pull-down circuitry; wherein the variable drive strength circuitry comprises a first inverter configuration and a second inverter configuration coupled in series, the first inverter configuration comprising a first p-channel transistor and a first n-channel transistor; wherein the pull-up circuitry comprises a second p-channel transistor and a third p-channel transistor coupled together in parallel with each other and in series with the first p-channel transistor; wherein the pull-down circuitry comprises a second n-channel transistor and a third n-channel transistor coupled together in parallel with each other and in series with the first n-channel transistor; wherein the second and third p-channel transistors have drains coupled to a source of the first p-channel transistor, and the second p-channel transistor has a gate coupled to the drains of the second and third p-channel transistors and to the source of the first p-channel transistor; and wherein the second and third n-channel transistors have drains coupled to a source of the first n-channel transistor and the second n-channel transistor has a gate coupled to the drains of the second and third n-channel transistors and to the source of the first n-channel transistor.