Patent ID: 7170347

Claim:
An input circuit that is arranged for rail-to-rail operation with a differential input signal, comprising: a differential input circuit for receiving the differential input signal, wherein the differential input circuit is configured to provide: a first positive differential current in response to the differential input signal, and a first negative differential current in response to the differential input signal; a differential trim circuit for enabling trimming of an offset, wherein the differential trim circuit is configured to provide: a second positive differential current in response to a differential positive trim signal; and a second negative differential current in response to a differential negative trim signal; and a current mirror stage for enabling a transconductance of the input circuit to be relatively constant for a common mode voltage of the differential input signal, comprising: a first current mirror circuit that is configured to receive a first current that is related to the common mode voltage, wherein the first current mirror circuit is further configured to reflect the first current to provide a first positive tail current to the differential input circuit, and further configured to reflect the first current to provide a second positive tail current to the differential trim circuit; and a second current mirror circuit that is configured to receive a second current that is related to the common mode voltage, wherein the second current mirror circuit is further configured to reflect the second current to provide a first negative tail current to the differential input circuit, and further configured to reflect the first current to provide a second negative tail current to the differential trim circuit; and an output stage for providing differential output currents.