Patent ID: 8432222

Claim:
An apparatus, comprising: a first level shifter having a first input, a second input, a first output, and a second output, wherein the first and second inputs are configured to receive a differential input voltage signal, and wherein the first level shifter is configured to control a common-mode voltage of the first and second outputs to be about equal to a first voltage and to control a difference in voltage between the first and second outputs based on the differential input voltage signal; a second level shifter having a first input, a second input, a first output, and a second output, wherein the second level shifter is configured to control a common-mode voltage of the first and second outputs to be about equal to the first voltage; a first transconductance amplification circuit having a first input, a second input, a first output, and a second output, wherein the first input of the first transconductance amplification circuit is electrically connected to the first output of the first level shifter; a second transconductance amplification circuit having a first input, a second input, a first output, and a second output, wherein the second input of the second transconductance amplification circuit is electrically connected to the second output of the second level shifter, and wherein the first and second outputs of the first transconductance amplification circuit are electrically connected to the second and first outputs of the second transconductance amplification circuit, respectively; and a transimpedance amplification circuit having a first input, a second input, and an output, wherein the first and second inputs are electrically connected to the first and second outputs of the first transconductance amplification circuit.