Abstract: An amplifier includes differential current sensing circuitry and an input bridge. Two paths of the input bridge receive the input signals and provide proportional current flows to the differential current sensing circuitry. The input bridge is configured to provide a differential offset voltage in one current path, and a complimentary voltage drop of equal magnitude in the other current path. In the examples, the input bridge includes a matched pair of transistors. To remove parallel incremental or small-signal conductance-related error sources, both transistors are operated at matched VDS (drain-to-source) voltages. The voltage offset, provided in association with one of the input transistors, serves to extend the range of certain circuits using the amplifier. The complimentary voltage drop in association with the other input transistor maintains the match of the VDS voltages for the two transistors.

Abstract: The circuits and methods of the present invention provide rail-to-rail output stages that cancel the non-linear components of the transconductances of transistors used in the output stages, that allow the idling current in the output stages to be controlled by external current sources and device size ratios, and that enable the idling current in the output stages to be maintained independently of manufacturing processes, temperature, and power supply voltages. The output stages generally comprise a complementary subcircuit, a current mirror and an output driver. The output stages receive an input signal and a bias voltage from an external source and responsively produce a push current that feeds current into a load and a pull current that pulls current from the load. When the push current matches the pull current, the output stages are said to be “idling.” The bias voltage controls the idling current.

Abstract: The circuits and methods of the present invention provide rail-to-rail output stages that cancel the non-linear components of the transconductances of transistors used in the output stages, that allow the idling current in the output stages to be controlled by external current sources and device size ratios, and that enable the idling current in the output stages to be maintained independently of manufacturing processes, temperature, and power supply voltages. The output stages generally comprise a complementary subcircuit, a current mirror and an output driver. The output stages receive an input signal and a bias voltage from an external source and responsively produce a push current that feeds current into a load and a pull current that pulls current from the load. When the push current matches the pull current, the output stages are said to be “idling.” The bias voltage controls the idling current.

Abstract: Circuits and techniques for controlling gain while performing analog frequency-selective filtering of electronic signals are provided. In particular, these circuits and techniques control gain and filter electronic signals in a way that significantly reduces input-referred noise as the gain increases to accommodate smaller input signals, while operating within reasonable power constraints and employing a minimum amount of die space. Such circuits also significantly reduce the circuitry necessary for performing the combined steps of controlling gain and doing analog frequency-selective filtering of electronic signals.