Systems and methods are disclosed for controlling nonequilibrium electron transport process and generating phonons in low dimensional materials. The systems can include a conductive sheet sandwiched between a first insulation layer and a second insulation layer; a first electrode conductively coupled to a first end of the conductive sheet; a second electrode conductively coupled to a second end of the conductive sheet; and a current source conductively coupled to the first electrode and the second electrode and configured to pass a current from the first electrode through the conductive sheet to the second electrode such that current generates a drift velocity of electrons in the conductive sheet that is greater than the speed of sound to generate phonons.

An ultra-low power sub-threshold g.sub.m stage is disclosed where transconductance is very stable with process, temperature, and voltage variations. This technique can be implemented in a differential amplifier with constant gain and a second order biquad filter with constant cut off frequency. The amplifier gain can achieve a small temperature coefficient of 48.6 ppm/ C. and exhibits small sigma of 75 mdB with process. The second order biquad can achieve temperature stability of 69 ppm/ C. and a voltage coefficient of only 49 ppm/mV.

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.

The present disclosure relates to a switchable power amplification structure including a first power amplifier (PA), a second PA, a front switching structure, and an end switching structure. The front switching structure is coupled to a radio frequency (RF) input port, and the end switching structure is coupled to an antenna port. Herein, the first PA and the second PA are parallel to each other, each of which is coupled between the front switching structure and the first end switching structure. The front switching structure is configured to selectively couple the first PA and the second PA to the RF input port, while the end switching structure is configured to selectively couple the first PA and the second PA to the first antenna port.

An apparatus comprises a plurality of selectable gain stages connected in parallel between a first bias voltage and ground, wherein each selectable gain stage comprises an amplification portion and a current steering portion, and wherein the current steering portion comprises a first selectable signal path connected between an output of the amplification portion and a signal output terminal, and a second selectable signal path connected between the output of the amplification portion and ground through a shunt device.

An amplifier comprises: an input stage, a pulse width modulation stage, and a switched output stage. During operation, the input stage receives an input signal (such as an audio signal). The input stage adjusts the input signal based on feedback from the switched output stage of the amplifier. According to one configuration, the feedback from the switched output stage is a voltage across a flying capacitor disposed in the switched output stage. The pulse width modulation stage uses the adjusted input signal or signals to produce respective pulse width modulation signals that are subsequently used to drive (control) switches in the switched output stage. The switches in the switched output stage generate an output voltage to drive a load based on states of the pulse width modulation signals. Adjustments applied to the input signal based on the feedback maintains the magnitude of the flying capacitor voltage at a desired setpoint.

A signal coupling method and apparatus is disclosed. A coupling network is coupled to convey signals from first functional circuit block to a second functional circuit block. The coupling network includes a first signal path having a first capacitor for providing AC coupling between the first and second functional circuit blocks. The coupling network further includes a second functional circuit block having a second signal path in parallel with the first signal path. The second signal path includes a switched capacitor circuit coupled to receive a first common mode voltage corresponding to the first functional circuit block and a second common mode voltage corresponding to the second functional circuit block.

A chopper amplifier circuit includes a first amplifier path with chopper circuitry, a switched-capacitor filter, and multiple gain stages. The chopper amplifier circuit also includes a second amplifier path with a feed-forward gain stage. A chopping frequency of the chopper circuitry is greater than a threshold frequency at which the second amplifier path is used instead of the first amplifier path.

Disclosed is an apparatus including a radio frequency amplifying circuit, a power supply circuit, and a bias generating circuit. The power supply circuit includes: a first power supply terminal coupled to a first ground terminal via a first capacitor and coupled to/decoupled from the radio frequency amplifying circuit through a first switch; and a second power supply terminal coupled to a second ground terminal via a second capacitor and coupled to/decoupled from the radio frequency amplifying circuit through a second switch, wherein the first capacitor and second capacitor are coupled to/decoupled from the radio frequency amplifying circuit through the first switch and second switch respectively, the supply voltages outputted from the two power supply terminals are different, and the two switches are not concurrently turned on. The radio frequency amplifying circuit operates according to a bias voltage provided by the bias generating circuit and one of the two supply voltages.

Embodiments of the disclosure are drawn to apparatuses and methods for transmission beamforming. A multiphase beam steering transmitter may include a transmitter array of multiple transmitters. A transmitter may include a multiphase logic decoder that directly controls a power amplifier to perform a vector addition of a beam phase and amplitude. A transmitter of the array may include a multiphase clock generator that outputs basis phases with embedded phase modulation data which are output to the multiphase logic decoder. The multiphase clock generator may receive a modulated clock signal. The PA may be a multiphase switched capacitor power amplifier. The multiphase logic decoder may output two phases adjacent to a desired phase as inputs to clocks of the SCPA. The multiphase logic decoder may further output a control signal that determines which cells in the SCPA are activated and when.