Patent ID: 7259589

Claim:
A differential signaling system comprising: a bus switch chip having a plurality of channels that connect a first bus to a second bus in response to a control signal being in a connect state, and that isolate the first bus from the second bus in response to the control signal being in an isolate state, the bus switch chip having a power-supply pin and a ground pin; a first differential transmitter that generates differential signals applied to the bus switch chip as the first bus; a differential receiver, coupled to the second bus from the bus switch chip, the differential receiver receiving differential signals passed through the bus switch chip from the first differential transmitter when the control signal is in the connect state; a ground supply having a ground voltage; a power supply having a power supply voltage above the ground voltage; a mid-level supply, having a mid voltage between the power supply voltage and the ground voltage; wherein the power supply voltage from the power supply is applied to the power-supply pin of the bus switch chip; wherein the mid voltage from the mid-level supply is applied to the ground pin of the bus switch chip; wherein the differential signals generated by the first differential transmitter swing within a voltage range that is between the mid voltage and the power supply voltage; and a plurality of pull-ups, coupled between the power supply voltage and the first bus, for driving the differential signals from the first differential transmitter above the mid voltage when the first differential transmitter is disabled, whereby the bus switch chip is supply-level shifted to pass the differential signals at the voltage range above the mid voltage applied to the ground pin of the bus switch chip.