Abstract: A method for controlling a supply voltage for a radio frequency power amplifier, that includes the steps of: determining (210) at least one parameter; determining (220) a constant voltage based on the at least one parameter; and automatically adjusting (230) the supply voltage to the constant voltage.

Abstract: A digital audio system to store and reproduce a digital PWM signal and a method of processing an audio signal. The method includes; converting an audio source signal into a digital pulse width modulation (PWM) signal through a series of signal processing processes and storing the PWM signal in a separate storage medium, when an audio signal is reproduced, reading the digital PWM signal stored in the storage medium and decoding the signal into an analog PWM signal, and performing a power switching operation with the decoded analog PWM signal and extracting an audio signal.

Abstract: A transmit filter (100) receives a stream of data symbols (DT_TX) at a baseband symbol clock rate. An available clock (FREF) is used to generate sample points for producing a generating an oversampled signal. The available clock is independent from the baseband symbol clock, and does not need to be an integer multiple of the clock. Upon identifying a start sequence in the data stream, a phase tracking circuit (106) is used to determine a current position relative to the baseband symbol clock. A state circuit (104) stores the last three, or more, data symbols. Based on the last three data symbols (which determines the shape of the curve for the current data symbol) and the current position (which determines the current position on the curve), a filter circuit (108) generates a sample point.

Abstract: A circuit having an enhanced input signal range includes a differential amplifier operative to receive at least first and second signals and to generate a difference signal at an output thereof which is a function of the difference between the first and second signals. The differential amplifier includes an input stage having at least first and second transistors having a first threshold voltage associated therewith and being operative to receive the first and second signals, respectively, and a load including at least third and fourth transistors having a second threshold voltage associated therewith, the first threshold voltage being greater than the second threshold voltage. The circuit further includes an output stage coupled to the differential amplifier and operative to receive the difference signal and to generate an output signal of the circuit that is indicative of the difference signal and is referenced to the supply voltage of the circuit.

Abstract: A radio frequency (RF) amplifier has a driver device, an output device, and first and second impedance transformation networks. In a first operating mode the output device is turned on and the first impedance transformation network presents a first load impedance to the output device. In a second operating mode, the output device is turned off and the second impedance transformation network connects an output of the driver device to the first impedance transformation network and presents a second load impedance to the driver device. The second load impedance is greater than the first load impedance.

Abstract: An amplifier circuit includes a first amplifier having an input and an output, and a second amplifier having an input that communicates with the output of the first amplifier, and an output. The amplifier circuit includes a first capacitance that communicates with the input of the first amplifier and the output of the second amplifier. The amplifier circuit includes a third amplifier having an input that communicates with the output of the second amplifier, and an output. The amplifier circuit includes a second capacitance that communicates with the output of the third amplifier and the input of the second amplifier.

Abstract: An amplifier having programmable amplification includes a transistor circuit having a plurality of negative feedback resistors, a switch being associated to a negative feedback resistor such that the negative feedback resistors of the transistor circuit can be activated and deactivated selectively by operating switches via a controller. Thus, a broadband amplifier having a high linearity can be implemented.

Abstract: A parallel power amplifier includes a carrier amplifier and peak amplifier coupled to receive signals from a quadrature hybrid made up of slab inductors in an integrated circuit. The slab inductors may be on different layers in the integrated circuit and may have similar or dissimilar shapes.

Abstract: A phonon laser pumped by a thermal gradient, the phonon laser having a coherent phonon pumping media, a heat source and a heat sink. The pumping media includes an array of micro resonators and a thermal phonon emitting media.

Abstract: A bipolar high output current buffer is disclosed using a negative feedback current mirror to supply the base drive to an output transistor. Small quiescent currents are used wherein the buffer demonstrates low quiescent power dissipation. The current mirror supplies the incremental base drive to the output transistor to support high output currents. When the output drive may source or sink the high output currents, two current mirrors may be used, one for each of the source and the sinking circuitry. This invention provides for minimal loss of dynamic range.

Abstract: A predistorter that linearizes the nonlinearity of a power amplifier in a system supporting a multimode and a multiband (frequency band). The predistorter includes a field-effect transistor, an impedance transform unit, a first inductor, a first capacitor, and a second capacitor. The field-effect transistor has a source connected to the ground and uses a variable gate bias voltage. The impedance transform unit is connected to a drain of the field-effect transistor to perform impedance transform. The first inductor is connected between the impedance transform unit and a voltage provided to the field-effect transistor. The first capacitor is connected between a power input terminal and the impedance transform unit. The second capacitor is connected between a power output terminal and the impedance transform unit.

Abstract: The present invention provides systems and methods for asymmetrically varying gain in a low noise amplifier. The amplifier includes a first stage amplifier, a plurality of second stage amplifiers coupled to the first stage amplifier, a comparator coupled to one of the second stage amplifiers, and a controller coupled to the comparator, the first stage amplifier, and the plurality of second stage amplifiers. The controller is configured to produce one or more gain control signals to change the gain of one of the first stage amplifier or the plurality of second stage amplifiers at a plurality of asymmetric rates so as to cause the power of the output signal to move toward one of the threshold values of the comparator. The rate of change of the gain is based on conditions including the gain of the first stage amplifier, gain of a second stage amplifier, and the sampled power level.

Abstract: According to an exemplary embodiment, an amplification module includes a power control circuit. The amplification module further includes a power amplifier coupled to the power control circuit and configured to draw a supply current and receive a supply voltage from the power control circuit. The power control circuit is configured to control a DC power provided to the power amplifier by controlling a product of a sense current, which is a mirror current of the supply current, and the supply voltage. The power control circuit includes a feedback voltage that corresponds to the product of the sense current and the supply voltage. The power control circuit further includes an analog multiplier circuit configured to receive the sense current and the supply voltage and generate the feedback voltage. The power control circuit further includes a differential error amplifier configured to compare the feedback voltage to a control voltage.

Abstract: Various source follower circuits and methods for implementing such are disclosed. As one example, a class AB source follower circuit is disclosed that includes a source follower circuit that is actively biased. The dynamic biasing allows the source follower circuit to sustainably sink a DC current. In some instances of the embodiments, the class AB source follower circuits are operable to source and sink both AC and DC currents.

Abstract: A Class S RF power amplifier for use in a radio frequency (RF) transmitter. The Class S power amplifier comprises a delta-sigma modulator that receives an analog modulated RF carrier and generates a pulse-width modulated binary signal. The Class S power amplifier also comprises a switch mode power amplifier that receives the pulse-width modulated binary signal generated by the delta-sigma modulator and generates an output carrier signal that switches between a fully on state and a fully off state. The sampling rate of the delta-sigma modulator is less than four times the frequency of the output carrier signal generated by the switch mode power amplifier.

Abstract: Embodiments of the present invention comprise methods and devices for amplifying a signal by amplifying a first signal and by then amplifying a second signal only if the first signal exceeds a predetermined threshold. The first and second amplified signals are then combined, and the combination is fed back to a signal source and used to control the values of the first and second signal. The combination is further transmitted to a load. In the preferred embodiment, the first amplified signal is transmitted through an impedance inverter before it is combined with the second amplified signal.

Abstract: Amplifier circuitry includes an input stage having a transconductance stage including first and second input transistors and a first tail current source, gates of the first and second input transistors being coupled to first and second input signals, respectively. A bulk electrode capacitance driver includes third and fourth input transistors and first and second associated cascode transistors and a second tail current source coupled to the sources and bulk electrodes of the third and fourth input transistors and to the bulk electrodes of the first and second input transistors. The gates of the third and fourth input transistors are coupled to the first and second input voltage signals, respectively, and the gates of the first and second cascode transistors are coupled to the second and first input voltage signals, respectively.

Abstract: A semiconductor integrated circuit includes a capacitor element which defines a prescribed decay time constant with one or more resistors, an MOS transistor connected to the capacitor element via its gate, and a constant current generating element which generates a constant current. The capacitor element is charged with the constant current so as to create a linearly changing voltage. The linearly changing voltage is applied to the gate so that the MOS transistor can accordingly output a smoothly changing current.

Abstract: An operational amplifier having a wide input common mode voltage range includes first (2) and second (3) differential input transistor pairs coupled to first (14) and second (15) tail current transistors. At least one of the first and second tail current transistor pairs is controlled by a common mode control circuit (4). A gate of the first tail current transistor (14) is coupled to the common mode control circuit (4) to turn the first tail current transistor on and to turn the second tail current transistor off when the common mode input voltage is below a common mode threshold voltage (CMTHR). A folded cascode stage (5) is driven by the first and second differential input transistor pairs.

Abstract: The present invention provides methods and apparatus for optimising power consumption in transistor amplifiers. The method comprises the step of adapting the amplifier characteristics of the transistor by adapting the bias impedance at the base of the transistor. The method may further comprise the step of adapting the amplifier characteristics of the transistor by adapting the quiescent collector current in the transistor.