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 IC for power conversion includes bias circuitry that generates one or more bias voltages. An adaptive biasing circuit adaptively shifts an input signal having a negative value to a positive value. An operational transconductance amplifier (OTA) receives a supply bias current and the first and second bias voltages. The OTA has first and second input terminals coupled to the input signal and ground, respectively. The OTA has first and second transistors coupled to the first and second input terminals through first and second resistors at first and second internal nodes, respectively. Additional circuitry of the OTA is coupled to the second internal node. The additional circuitry insures that the voltage at the second internal node follows the voltage at the first internal node. The OTA generates an output current signal responsive to a differential input voltage applied across the first and second input terminals.

A magnetic resonance wireless power transmission device capable of adjusting resonance frequency is disclosed. A wireless power transmission device according to an embodiment of the present invention comprises: a power amplifier for amplifying a wireless power signal using a driving frequency signal; a resonator for configuring a resonance tank and wirelessly transmitting, through magnetic resonance, the wireless power signal output from the power amplifier using a resonance frequency of the resonance tank; and a resonance control unit for controlling a duty ratio using a frequency applied to the resonator or a frequency signal generated by the resonator and adjusting the resonance frequency of the resonator.

A transmission chain receives an incident signal to be transmitted having a first power and a first bandwidth. A first modulator frequency shifts a first signal derived from the incident signal to generate a first shifted signal at a modulation output. A power amplifier coupled to the modulation output amplifies an intermediate signal to generate an amplified output signal. A predistortion-signal-generating circuit generates, from the incident signal and from the amplified output signal in a second bandwidth that is larger than the first bandwidth, a predistortion signal having a second power lower than the first power. A second modulator frequency shifts a second signal derived from the predistortion signal to generate a second shifted signal for combination with the first shifted signal at said modulation output to produce the intermediate signal.

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.

An IC for power conversion includes bias circuitry that generates one or more bias voltages. An adaptive biasing circuit adaptively shifts an input signal having a negative value to a positive value. An operational transconductance amplifier (OTA) receives a supply bias current and the first and second bias voltages. The OTA has first and second input terminals coupled to the input signal and ground, respectively. The OTA has first and second transistors coupled to the first and second input terminals through first and second resistors at first and second internal nodes, respectively. Additional circuitry of the OTA is coupled to the second internal node. The additional circuitry insures that the voltage at the second internal node follows the voltage at the first internal node. The OTA generates an output current signal responsive to a differential input voltage applied across the first and second input terminals.

A transmission chain receives an incident signal to be transmitted having a first power and a first bandwidth. A first modulator frequency shifts a first signal derived from the incident signal to generate a first shifted signal at a modulation output. A power amplifier coupled to the modulation output amplifies an intermediate signal to generate an amplified output signal. A predistortion-signal-generating circuit generates, from the incident signal and from the amplified output signal in a second bandwidth that is larger than the first bandwidth, a predistortion signal having a second power lower than the first power. A second modulator frequency shifts a second signal derived from the predistortion signal to generate a second shifted signal for combination with the first shifted signal at said modulation output to produce the intermediate signal.

A headphone driver, a sound processor that incorporates the headphone driver and a computing system that incorporates the headphone driver, wherein the headphone driver includes an amplifier having an input terminal and an output terminal, an R-2R ladder network provided with an input signal and connected to the input terminal of the amplifier, and a feedback resistor group connected to the input terminal and to the output terminal of the amplifier. The R-2R ladder network includes a plurality of resistor branches and a first attenuator that is connected between the plurality of resistor branches.

A loop compensation circuit includes a differential difference amplifier having a first transconductance stage with a first input terminal and a second input terminal. The first input terminal is coupled to a voltage reference and the second input terminal is coupled to a feedback node. The amplifier also includes a second transconductance stage having a third input terminal and a fourth input terminal. The third input terminal is coupled to a virtually specified fixed voltage and the fourth input terminal is coupled to a fixed specified voltage. The loop compensation circuit also includes a feedback impedance coupled between an output of the differential difference amplifier and the third input terminal and a second impedance between the third input terminal and the fixed specified voltage.

Embodiments of the present disclosure provide apparatuses and methods for balancing parasitic capacitances between metal tracks in an integrated circuit chip. Specifically, additional capacitances in the form of, for example, tab capacitors, are attached to the metal tracks with the intention of detaching a select number of the attached capacitances for the purpose of balancing the parasitic capacitances between the metal tracks. The attached capacitances may be structural metal elements. Further, the attached structural metal elements may be detachable at thin-film resistive material associated with each of the attached structural metal elements.