Patent ID: 6943587

Claim:
An integrated circuit that services an interface supporting at least two voltage domains, the integrated circuit comprising: a core circuit that operates at a core supply voltage; and a buffer circuit operably coupled to the core circuit that interfaces the core circuit to a set of input lines and a set of output lines, wherein each of the set of input lines and each of the set of output lines is controllable to support the at least two voltage domains, wherein the buffer circuit comprises: a plurality of input buffers that are controllable to support the at least two voltage domains, each of the plurality of input buffers comprising: a pass gate that receives the input signal to limit the range of the input signal; an input buffer rail circuit that produces an input buffer rail voltage that is based upon a selected voltage domain of the at least two voltage domains; and an inverter powered by the input buffer rail voltage that receives an input signal corresponding to one of the at least two voltage domains and that produces an input signal to the core circuit that is consistent with the core supply voltage; and a plurality of output buffers that are controllable to support the at least two voltage domains.