A method of controlling a headroom voltage of a transistor stage of an electroplating system to maintain a target power dissipation across the transistor stage may include maintaining a headroom voltage in the transistor stage for a load in the electroplating system. The method may also include measuring an instantaneous power dissipation in the transistor stage and generating a difference output representing a difference between the instantaneous power dissipation in the transistor stage and the target power dissipation in the transistor stage. A voltage across the transistor stage and the load may then be adjusted using the difference output such that the headroom voltage in the transistor stage is adjusted to maintain the target power dissipation in the transistor stage.

Techniques for shielding wearable surface electromyography (sEMG) devices are described. According to some aspects, an sEMG device may comprise amplification circuitry comprising at least a first differential amplifier and at least two sEMG electrodes electrically connected to the amplification circuitry. The device may further comprise at least one auxiliary conductor not electrically connected to the amplification circuitry, wherein the at least one auxiliary conductor is configured to be electrically coupled to a wearer of the wearable device, and an electromagnetic shield surrounding the wearable device at least in part and electrically connected to the at least one auxiliary conductor.

An example apparatus includes: a first voltage source, a first amplifier having a noninverting input adapted to be coupled to a photodiode anode and coupled to the first voltage source, an inverting input adapted to be coupled to a photodiode cathode, and an output, a first resistor coupled to the first amplifier inverting input and to the first amplifier output, a first capacitor coupled to the inverting input of the first amplifier and the first amplifier output, and a second voltage source different from the first voltage source. There is a second amplifier having a noninverting input, an inverting input and an output. The noninverting input is coupled to the output of the first amplifier, the inverting input is coupled to the second voltage source, and there is a second resistor coupled to the inverting input and the output of the second amplifier.

An isolation amplification circuit having an input stage circuitry and a control circuitry stage interconnected through a galvanic isolation barrier. The input stage circuitry includes a first filter network and a second filter network for supplying first and second output signals in response to the application of first and second electrical input signals. The input stage circuitry includes a first feedback path configured for applying a first feedback signal to a common node of the first filter network to close a first feedback loop around the first filter network and a second feedback path configured for applying a second feedback signal to a common node of the second filter network to close a second feedback loop around the second filter network.

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.

Disclosed is a 5G (5.sup.th generation) or pre-5G communication system for supporting a data transmission rate higher than that of a 4G (4.sup.th generation) communication system such as long-term evolution (LTE). A transmission device comprises: a first amplification unit having a common source structure, including cross coupled capacitors, and amplifying an input signal; a second amplification unit, having a common gate structure, for amplifying a signal output from the first amplification unit; and a first removal unit which is connected to output terminals of the first amplification unit and input terminals of the second amplification unit and which removes at least one portion of second harmonics. The first removal unit can offset, with respect to a fundamental frequency, at least some of parasitic capacitance generated from the output terminals of the first amplification unit and the input terminals of the second amplification unit, and can ground a signal having a secondary harmonic frequency with respect to the secondary harmonic frequency.

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.

According to an example aspect of the present invention, there is provided an apparatus comprising two charge amplifiers configured to receive input from an acceleration sensor and to each produce one first output signal, a differential amplifier configured to receive the first output signals and to amplify a difference between the first output signals to produce two second outputs signals.

Circuit for wireless communication are provided, the circuits comprising: a first quadrature hybrid having a first in port, a first iso port, a first cpl port, and a first thru port; a first mixer having a first input coupled to the first cpl port and having an output; a second mixer have a first input coupled to the first cpl port and having an output; a third mixer having a first input coupled to the first thru port and having an output; a fourth mixer having a first input coupled to the first thru port and having an output; and a first complex combiner having inputs coupled to the output of the first mixer, the output of the second mixer, the output of the third mixer, and the output of the fourth mixer that provides first I and Q outputs based the output of the first mixer and the output of the second mixer.

A wireless receiving device is provided. The wireless receiving device includes a first passive mixer and a common gate amplifier. The first passive mixer receives an oscillation signal. The common gate amplifier is coupled to the first passive mixer, and automatically adjusts the input impedance of the common gate amplifier according to the oscillation frequency of the oscillation signal.