Abstract: A low voltage differential signal detector capable of detecting low-voltage differential signals over a large common-mode voltage range. The signal detector uses two differential pairs of opposite conductivity type, coupled to each other in a self-biasing manner to detect low voltage swings in a signal over a large common-mode voltage range. Depending upon the common-mode voltage level of the signal, the low-voltage level swings will be detected by one of the differential pairs, the other of the differential pairs or both.

Abstract: A full-duplex, differential, bi-directional communications link for simultaneously transmitting differential data between electronic devices is provided. Each transceiver coupled to the communications channel comprises a CMOS (Complementary Metal-Oxide Semiconductor) differential driver and receiver. The differential driver provides constant CMOS voltage sources for providing stable data signal transmission at reduced voltage levels. Voltage sources providing a data signal voltage different from the desired data signal voltage can be placed into a high impedance mode to allow the desired data signal voltage to be transmitted on the common line. The differential receiver includes self-biasing feedback circuitry to provide biasing voltages to the circuit while avoiding manufacturing difficulties associated with providing precise bias voltages. The complementary amplifier structure of the receiver provides an increased common mode noise tolerance.