Floating input amplifier for capacitively coupled communication

摘要

One embodiment of the present invention provides a capacitively-coupled receiver amplifier that has an input with no DC coupling. A DC voltage is programmed on the input. During programming, a transmitter is held at a voltage at a midpoint between a voltage that represents a logical "1" and a voltage that represents a logical "0" and the input voltage of the receiver amplifier is programmed to be substantially the switching-threshold voltage for the receiver amplifier. Then, during normal data communication, the transmitter drives high and low electrical signals that are coupled to the receiver amplifier. Since the input of the receiver amplifier has been substantially set to the DC voltage, the receiver amplifier need not control the DC voltage of the input for each transition in the electrical signals.