Wideband common-mode regulation circuit

Abstract

A wideband common-mode regulation circuit for coupling a differential amplifier, or more particularly a Low Voltage Differential Signaling driver LVDS, to a load generally constituted by a telecommunication transmission line. The regulation circuit only comprises a first resistive pair (R1, R2) to sense the common-mode voltage at the differential input terminals (INP, INN), a second resistive pair (R3, R4) to force the voltage across the load to a predetermined value, and an active device (OTA, INV) coupled between the junction points of the first and the second resistive pairs. The active device is an Operational Transconductance Amplifier (OTA) or, preferably, an inverter (INV). Owing to reduced number of non-dominant poles in the common-mode open-loop transfer characteristic, this regulation circuit provides common-mode loop stability for wide common-mode loop bandwidth.

Dependencies are inferred from the claim text.