Apparatus to convert electrical signals from small-signal format to rail-to-rail format

A method for signal-format conversion, the method comprising:

• shifting a common-mode voltage of a differential signal to obtain a level-shifted differential signal;
• amplifying the level-shifted differential signal into an amplified differential signal using an amplifier;
• converting the amplified differential signal into a rail-to-rail signal;
• generating a feedback voltage that is proportional to an output common-mode voltage of the amplifier;
• and
• generating a bias voltage for input to the amplifier based on a difference between the feedback voltage and a reference voltage, wherein the output common-mode voltage of the amplifier depends on the bias voltage.

An apparatus for signal-format conversion, comprising:

• means for shifting a common-mode voltage of a differential signal to obtain a level-shifted differential signal;
• means for amplifying the level-shifted differential signal into an amplifier differential signal using an amplifier;
• means for converting the amplified differential signal into a rail-to-rail signal;
• means for generating a feedback voltage that is proportional to an output common-mode voltage of the amplifier;
• and
• means for generating a bias voltage for input to the amplifier based on a difference between the feedback voltage and a reference voltage, wherein the output common-mode voltage of the amplifier depends on the bias voltage.

A receiver, comprising:

• an amplifier configured to amplify a differential signal into an amplified differential signal;
• a driver stage configured to convert the amplified differential signal into a rail-to-rail signal;
• a common-mode voltage detection circuit configured to detect an input common-mode voltage of the amplifier;
• a replica circuit that is driven by the detected input common-mode voltage, and configured to generate a feedback voltage based on the detected input common-mode voltage;
• and
• a comparator having a first input configured to receive the feedback voltage, and a second input configured to receive a reference voltage, and configured to generate a bias voltage for input to the amplifier based on a difference between the feedback voltage and the reference voltage.