1. A circuit for receiving a low voltage differential signal having a common mode voltage range, the circuit comprising: a first amplifier circuit which operates in a first voltage sub-range of the common mode voltage range: a second amplifier circuit which operates in a second voltage sub-range of the common mode voltage range, and, a control circuit for controlling the operation of the first and second amplifier circuits so as to provide an output signal over the common mode voltage range of the input signal, wherein the control circuit sums the output of the first and second amplifiers in an overlapping region of the first and second voltage sub-ranges.