A chopper-stabilized amplifier includes a first transconductance amplifier and a first chopper circuit coupled to an input of the first transconductance amplifier. A second chopper circuit is coupled to an output of the first transconductance amplifier. The chopper-stabilized amplifier also includes second and third transconductance amplifiers having inputs coupled to the output of the first transconductance amplifier. The second transconductance amplifier produces an output responsive to a first notch clock signal having a first phase relative to the chopping of the second chopper circuit. The third transconductance amplifier produces an output responsive to a second notch clock signal having a second phase relative to the first phase. The output signals produced by the second and third transconductance amplifiers are added to filter ripple noise at the outputs of the second and third transconductance amplifiers.

In accordance with embodiments of the present disclosure, a method for power supply rejection for an amplifier may include generating a correction signal by multiplying a quantity indicative of a power supply voltage of the amplifier by a transfer function defining a response from the power supply voltage of the amplifier to an output signal of the amplifier and subtracting the correction signal from a signal within a signal path of a circuit comprising the amplifier.

A pseudo-resistor structure, comprises: a first and a second PMOS transistor or PN diode configured as two-terminal devices, wherein the positive terminal of the first PMOS transistor or PN diode is connected to the positive terminal of the second PMOS transistor or PN diode, and wherein the negative terminal of the first PMOS transistor or PN diode is connected to an input (A) of the pseudo-resistor structure and wherein the negative terminal of the second PMOS transistor or PN diode is connected to an output (C) of the pseudo-resistor structure, and a dummy transistor or dummy diode connected to the input (A), wherein the dummy transistor or dummy diode is further connected to a bias voltage for compensating a leakage current through the first and the second PMOS transistors or PN diodes. A closed-loop operational amplifier circuit comprising the pseudo-resistor structure is provided. Also, a bio-potential sensor comprising the closed-loop operational amplifier circuit is provided.

In accordance with embodiments of the present disclosure, a method for power supply rejection for an amplifier may include generating a correction signal by multiplying a quantity indicative of a power supply voltage of the amplifier by a transfer function defining a response from the power supply voltage of the amplifier to an output signal of the amplifier and subtracting the correction signal from a signal within a signal path of a circuit comprising the amplifier.

In accordance with embodiments of the present disclosure, a method for power supply rejection for an amplifier may include generating a correction signal by multiplying a quantity indicative of a power supply voltage of the amplifier by a transfer function defining a response from the power supply voltage of the amplifier to an output signal of the amplifier and subtracting the correction signal from a signal within a signal path of a circuit comprising the amplifier.

The present disclosure includes a photodetector element (11) that converts an optical signal into an electric current signal; a transimpedance amplifier (12a) that converts the electric current signal into a voltage signal; a differential amplifier (12d) that converts the voltage signal into a differential signal, by performing differential amplification of a difference between the voltage signal and a threshold voltage; an LOS detection circuit that detects a no-signal section of the optical signal; and an MCU that repeatedly executes offset cancellation processing, the offset cancellation processing including threshold voltage change processing in which the threshold voltage is changed such that an offset voltage of the differential signal is reduced, the MCU 13 skipping the threshold voltage change processing in the no-signal section.

The present disclosure includes a photodetector element (11) that converts an optical signal into an electric current signal; a transimpedance amplifier (12a) that converts the electric current signal into a voltage signal; a differential amplifier (12d) that converts the voltage signal into a differential signal, by performing differential amplification of a difference between the voltage signal and a threshold voltage; an LOS detection circuit that detects a no-signal section of the optical signal; and an MCU that repeatedly executes offset cancellation processing, the offset cancellation processing including threshold voltage change processing in which the threshold voltage is changed such that an offset voltage of the differential signal is reduced, the MCU 13 skipping the threshold voltage change processing in the no-signal section.

An autozero amplifier may include a window comparator network to monitor an output offset of a differential amplifier. The autozero amplifier may also include an integrator to receive a signal from a latched window comparator network, and send an adjustment signal back to the differential amplifier to reduce an offset of the differential amplifier.

A method and circuit for dynamically correcting offsets associated with an AC power system. In an embodiment, a first offset current generated in response to a ground to neutral fault stimulus is decreased and a second offset current generated in response to a differential fault stimulus is decreased. In another embodiment, the circuit includes an offset correction circuit that has one of a chopper circuit or an auto-zeroing circuit. An amplifier is connected to the offset correction circuit and an output connected to the offset correction circuit. A signal generator is switchably coupled to a first input of the offset correction circuit and a bias generator is switchably coupled to the first input of the offset correction circuit.

An autozero amplifier may include a window comparator network to monitor an output offset of a differential amplifier. The autozero amplifier may also include an integrator to receive a signal from a latched window comparator network, and send an adjustment signal back to the differential amplifier to reduce an offset of the differential amplifier.