Patent ID: 8643973

Claim:
An apparatus comprising: a transmission terminal; a transmitter that is coupled to the transmission terminal; and a compensator having: a reflection cancellation driver that is coupled to the transmission terminal, wherein the reflection cancellation driver injects a current at a delay; a reflection sensor that is coupled to the transmission terminal; a predriver that is coupled to the reflection cancellation driver and the reflection sensor, wherein, in a calibration mode, the reflection cancellation predriver iteratively adjusts the delay to determine a compensation delay, wherein the current provided at the compensation delay substantially compensates for a reflection current received by the transmission terminal; wherein the transmitter further comprises: the predriver; and a transmission driver that is coupled between the predriver and the transmission terminal; wherein the reflection cancellation circuit further comprises: a first adjustable current source that is coupled to the transmission terminal; and a second adjustable current source that is coupled the transmission terminal, wherein the first and second adjustable current sources are controlled by the predriver; wherein the transmission terminal further comprises a first transmission terminal and a second transmission terminal, and wherein the transmission driver further comprises a first transmission driver that is coupled to the first transmission terminal and a second transmission driver that is coupled to the second transmission terminal, and wherein the reflection cancellation circuit further comprises a first reflection cancellation circuit that is coupled to the first transmission terminal and a second reflection cancellation circuit that is coupled to the second transmission terminal; wherein the reflection sensor further comprises: a differential amplifier that is coupled across the first and second transmission terminals; and an analog-to-digital converter (ADC) that is coupled between the differential amplifier and the predriver; wherein the reflection sensor further comprises a sampling circuit that is coupled to between differential amplifier and the ADC; wherein the reflection sensor further comprises logic that is coupled between the predriver and the sampling circuit; wherein the logic further comprises: a delay circuit that is coupled to the predriver; and a logic gate that is coupled to the delay circuit, the reflection cancellation predriver and the sampling circuit; wherein the sampling circuit further comprises: a switch that is coupled between the differential amplifier and the ADC; and a capacitor that is coupled to the switch and the ADC.