Patent ID: 7696787

Claim:
A bus interface circuit for providing an output signal to an interface bus electrically connected to a remote receiver, said bus interface circuit comprising: an input node for receiving an input signal; at least one output terminal for electrical connection to said interface bus, wherein said bus interface circuit provides a current from said at least one output terminal to communicate a present value of said input signal to said remote receiver over said interface bus; a storage for storing at least one previous value of said input signal; a pre-emphasis circuit for adjusting said current dynamically in conformity with said present value of said input signal and at least one previous value of said input signal, and wherein a rate of change of said current is varied dynamically in conformity with a difference between said present value and said at least one previous value; and a primary driver current source having a polarity set in accordance with said present value, and wherein said pre-emphasis circuit comprises a secondary current source having a polarity set in accordance with said at least one previous value, and wherein said secondary current source has at least one controlled rate of current change substantially slower than a rate of current change in said primary driver, wherein said secondary current source has two controlled rates of current change selected in conformity with a logical exclusive-OR of said present value and said at least one previous value.