A transconductance amplifier (TCA) implemented with high electron mobility transistors (HEMTs) in a push-pull amplifier output stage provides a voltage controlled constant high output current to loads ranging from 10 mΩ to 1Ω with a bandwidth of 25 MHz. A driving stage for the HEMTs is implemented with variable gain amplifiers that amplify the input voltage signal and provide bias for the HEMTs. An automatic gain control may be connected between the TCA output and the variable gain amplifiers to ensure a constant current output for a varying load.

One or more examples relate to an apparatus to amplify differential voltage signal components of voltage across a resistor. Such an apparatus may include a resistor; a differential amplification circuit operatively coupled with the resistor to amplify a differential voltage signal component of a voltage across the resistor; and an operative coupling between the resistor and the differential amplification circuit to pass the differential voltage signal component and isolate a common mode voltage signal component of the voltage across the resistor.

An amplifier includes: a signal polarity inversion circuit which modulates an input signal and outputs a modulation signal; an amplifier circuit which is constituted from an operational transconductance amplifier (OTA) to amplify the modulation signal and output a current; and a sample-hold circuit having a sampling capacitor which is charged and discharged by selective sampling of the output current of the amplifier circuit and a holding capacitor to which the voltage of the sampling capacitor is transferred.

A peak detector includes an asymmetrical latch having a first input and a second input; and a CMOS converter having a first input coupled to a first output of the asymmetrical latch, a second input coupled to a second output of the asymmetrical latch, and an output.

An electromyography (EMG) device according to an aspect of the present disclosure includes a main circuit board having opposing first and second faces. A plurality of first connectors of a first type are provided on the first face, and a plurality of input contacts are provided on the second face. An EMG circuit is provided on the main circuit board. The EMG circuit is configured to utilize the input contacts as inputs to obtain an EMG input signal, and process the EMG input signal to provide an EMG output signal that is based on, but different from, the EMG input signal. For each of the input contacts, there is no conductive path directly between the input contact and any of the first connectors.

The present application discloses an amplifier circuit, a chip and an electronic device, which generates a positive output signal and a negative output signal according to a positive input signal and a negative input signal, wherein the positive input signal and the negative input signal have a corresponding input differential-mode voltage and input common-mode voltage, and the positive output signal and the negative output signal have a corresponding output differential-mode voltage and output common-mode voltage, and the amplifier circuit includes: an amplifying unit, configured to receive the positive input signal and the negative input signal and generate the positive output signal and the negative output signal; and an attenuation unit, including: a positive common-mode capacitor and a negative common-mode capacitor, configured to attenuate the input common-mode voltage below a first specific frequency.

A neural network circuit that uses a ramp function as an activation function includes a memory device in which memristors serving as memory elements are connected in a matrix. The neural network circuit further includes I-V conversion amplification circuits for converting currents flowing via the memory elements into voltages, a differential amplifier circuit for performing a differential operation on outputs of two I-V conversion amplification circuits, an A-D converter for performing an A-D conversion on a result of the differential operation, and an output determine that, by referring to input signals of the differential amplifier circuit, determines whether an output signal value of the differential amplifier circuit belongs to an active region or an inactive region. Based on a determination result, the input determiner switches over the differential amplifier circuit and the A-D converter between an operating state and a standby state.

An operational amplifier includes a pre-amplifier circuit, a first trim circuit, and a second trim circuit. The pre-amplifier circuit is to include a differential pair and receive an input voltage. The first trim circuit is to produce an offset voltage correction current and provide the offset voltage correction current to the pre-amplifier circuit to correct an offset of the operational amplifier. The second trim circuit is to produce a common mode voltage (VCM) correction current, provide the VCM voltage correction current to the pre-amplifier circuit, and cause the VCM correction current to have a non-zero value to reduce a correction caused by the offset voltage correction current when the input voltage is within a mid voltage input range. The pre-amplifier circuit is to apply the offset correction current and the VCM correction current to output signals of the differential pair.

An apparatus for turning off a cascode amplifier having a common-gate transistor and a common-source transistor is disclosed that includes the cascode amplifier, a feedback circuit, and a bias circuit. The feedback circuit is configured to receive a drain-voltage from the drain of the common-source transistor when the common-source transistor is switched to a first OFF state and produce a first feedback signal. The drain-voltage is equal to a source voltage of the common-gate transistor and the drain-voltage increases in response to switching the common-source transistor to the first OFF state. The bias circuit is configured to receive the first feedback signal and produce a bias-voltage. A first gate-voltage is produced from the bias-voltage. The cascode amplifier is configured to receive the first gate-voltage and a second gate-voltage. The common-gate transistor is configured to switch to a second OFF state in response to receiving the second gate-voltage.

According to one embodiment, a semiconductor circuit includes a first transimpedance amplifier and a second transimpedance amplifier. The first transimpedance amplifier is configured to convert an input current to a first output voltage and output the first output voltage from a first output terminal when a reference voltage is supplied to a first input terminal and the input current is supplied to a second input terminal. The second transimpedance amplifier has a circuit configuration similar to a circuit configuration of the first transimpedance amplifier. The second transimpedance amplifier is configured to output a second output voltage from a second output terminal when the reference voltage is supplied to a third input terminal.