Differential switching output stage for audio, power and digital data transmission can cause a common mode error due to asymmetric transition between positive and negative outputs. Systems and methods are provided for common mode error correction. In particular, summing nodes, novel error amps an edge switching can be used for common-mode feedback (CMFB) in differential signaling and other applications.

An amplification circuit with a common-mode voltage compensation circuit is shown. The common-mode voltage compensation circuit has a first compensation resistor coupled between an input terminal of a loop filter of the amplification circuit and a control node, and a second compensation resistor coupled between another input terminal of the loop filter and the control node. The control node is coupled to a power ground voltage when the two output signals of the amplification circuit are high, and it is coupled to a power supply voltage when the two output signals of the amplification circuit are low.

A reference buffer circuit comprises a dual-difference amplifier circuit including a first differential input, a second differential input, and a differential output that provides a differential reference signal; a first reference voltage coupled to a first input of the first differential input and a second reference voltage coupled to a first input of the second differential input; and wherein outputs of the differential output are connected by a feedback circuit path to second inputs of the first and second differential inputs.

An instrumentation amplifier configured for providing high common mode rejection and low distortion is described and includes an input differential pair configured to receive a differential input voltage and differential feedback voltage and a folded cascode amplifying stage configured to receive output current mode signals provided from the input differential pair. A current mirror is configured to mirror output current mode signals provided from said folded cascode amplifying stage. An external gain setting configuration may include a resistor feedback network, which includes a first resistor being connected between feedback inputs of said input differential pair, a second resistor between an output terminal of the current mirror and a first feedback input of said input differential pair, a third resistor between a common terminal and a second feedback input of said input differential pair.

An instrumentation amplifier configured for providing high common mode rejection and low distortion is described and includes an input differential pair configured to receive a differential input voltage and differential feedback voltage and a folded cascode amplifying stage configured to receive output current mode signals provided from the input differential pair. A current mirror is configured to mirror output current mode signals provided from said folded cascode amplifying stage. An external gain setting configuration may include a resistor feedback network, which includes a first resistor being connected between feedback inputs of said input differential pair, a second resistor between an output terminal of the current mirror and a first feedback input of said input differential pair, a third resistor between a common terminal and a second feedback input of said input differential pair.

An apparatus is provided. There is an input terminal that is configured to receive an input signal from a optical receiver and an output terminal. First and second integrators are coupled between the input and output terminals. In the second integrator, there is a current source that is coupled to the input terminal, a first resistor that is coupled to the output terminal, and a second resistor. Also, there is an amplifier having a first input, a second input, and an output, where the first resistor is coupled to the first input of the amplifier and where the second input of the amplifier is configured to receive a reference voltage. A transistor is coupled between the current source the second resistor and is coupled to the output of the amplifier at its gate. A capacitor is also coupled between the first input of the amplifier and the second resistor.