An analog discrete current mode negative feedback amplifier circuit for use with a micro-fused strain gauge is disclosed. The amplifier circuit includes a Wheatstone bridge coupled to a first power supply and a second power supply. The first power supply and the second power supply can be configured such that the periodically alternate between two voltage levels. The Wheatstone bridge can be coupled to a negative feedback amplifier circuit with common mode detection. The amplifier circuit can comprise a differential amplifier with a negative feedback configuration coupled to a common mode amplifier. In addition, the output of each of the amplifiers can be coupled to a common-mode amplifier. In a pressure sensing application, the output of the common mode amplifier serves to output the temperature while the differential amplifiers serve to output the pressure.

An embodiment of an amplifier circuit includes first, second, and third amplifiers. The first and second amplifiers are configured to amplify a differential input signal with a non-inverting gain. And the third amplifier, which can be a transconductance amplifier, is configured to cause the first and second amplifiers to amplify a common-mode input signal with a gain that is less than unity. The third amplifier can also be configured to cause the first and second amplifiers to generate a common-mode output voltage that is substantially independent of the common-mode input voltage. Consequently, in addition to presenting a high input impedance and a low noise factor, such an amplifier circuit has a configurable common-mode output voltage and has a lower common-mode gain (e.g., less than unity, approaching zero) than other non-inverting differential amplifiers.

A differential all-pass coupling circuit with common mode feedback is disclosed. An example apparatus includes an anti-aliasing circuit configured to reduce a bandwidth of a first differential signal, and a switched-capacitor circuit coupled to the anti-aliasing circuit configured to control a first switch to charge a capacitor to a first voltage based on a first difference between (i) a common mode input voltage associated with a first common mode voltage of the first differential signal and (ii) a common mode reference voltage associated with a second common mode voltage of an input stage of the receiver, control a second switch to provide a second voltage to the capacitor based on a second difference between the first differential signal and the common mode input voltage, and output a second differential signal to the input stage based on the first differential signal adjusted by the second voltage.

The present disclosure relates to a current sensor, including a magnetic-field sensor for measuring a magnetic field induced by an electrical current; an output connection for providing an amplified measurement signal from the magnetic-field sensor, the magnetic-field sensor and the output connection being connected by an analog signal path having at least one amplifier, the analog signal path having a frequency response; a temperature sensor for measuring a temperature; and a compensation circuit which is coupled to the analog signal path and is configured to correct the frequency response of the analog signal path based on the temperature.

The disclosure has a semiconductor IC chip formed with: a feedback amplification circuit, generating an output voltage supplied to a capacitive load by transmitting a current corresponding to a difference between an input voltage and a feedback voltage to the first pad via a first wiring; and a feedback resistor, receiving a voltage received by the second pad via a second wiring not connected with the first wiring, and generating, as the feedback voltage, a voltage obtained by dividing the voltage received via the second wiring.

At least some embodiments are directed to a system that comprises a differential input transistor pair (DITP) comprising first and second transistors, a first feedback loop coupled to the first transistor, and a second feedback loop coupled to the second transistor. When a differential voltage applied to the input stage is within a first range, the first and second feedback loops control a tail current supplied to the DITP, where the tail current at least partially determines a transconductance of the DITP. When the differential voltage is within a second range, the transconductance of the DITP is at least partially determined by a first resistor in the first feedback loop or by a second resistor in the second feedback loop.

An embodiment of an amplifier circuit includes first, second, and third amplifiers. The first and second amplifiers are configured to amplify a differential input signal with a non-inverting gain. And the third amplifier, which can be a transconductance amplifier, is configured to cause the first and second amplifiers to amplify a common-mode input signal with a gain that is less than unity. The third amplifier can also be configured to cause the first and second amplifiers to generate a common-mode output voltage that is substantially independent of the common-mode input voltage. Consequently, in addition to presenting a high input impedance and a low noise factor, such an amplifier circuit has a configurable common-mode output voltage and has a lower common-mode gain (e.g., less than unity, approaching zero) than other non-inverting differential amplifiers.

A fingerprint sensing circuit and a fingerprint sensing apparatus are provided. The fingerprint sensing circuit includes a sensing electrode; a first converting circuit connected to the sensing electrode and configured to convert a coupling capacitance sensed by the sensing electrode into a drive voltage, where the drive voltage is equal to a sum of a voltage variation converted from the coupling capacitance and a reference voltage; and a second converting circuit configured to generate a sensing current based on the drive voltage, and send the sensing current to a fingerprint signal processor, where the sensing current is equal to a product of a transconductance gain of the second converting circuit and the voltage variation, and the fingerprint signal processor performs fingerprint sensing based on the sensing current. With the fingerprint sensing circuit and the fingerprint sensing apparatus, the detection accuracy can be improved.

Provided are an amplifier circuit capable of reducing DC offset voltage without an increase in chip area and degradation in frequency characteristics, and a multipath nested miller amplifier circuit. The amplifier circuit includes a chopper switching circuit, a sampling circuit configured to sample an output signal from the chopper switching circuit, and a holding circuit configured to hold a signal output from the sampling circuit.

Various aspects of this disclosure describe reducing distortion of a power amplifier by coupling a common mode signal, such as determined from a voltage supply signal of the power amplifier or output of the power amplifier, to an input of the power amplifier. A resistive digital-to-analog converter (DAC) can be coupled to the power amplifier, and a common mode signal is modulated onto differential reference voltages of the DAC, causing the common mode signal to exist at both the input and output of the power amplifier at approximately the same time. Consequently, current flowing at differential inputs of the power amplifier due to the common mode component drops to zero, causing distortions due to common mode to differential mode conversion to be reduced.