An envelope tracking system includes an instantaneous amplitude circuitry, an instantaneous frequency circuitry, and a two-dimensional (2D) bias voltage selection circuitry. The instantaneous amplitude circuitry is configured to determine an instantaneous amplitude of a transmit signal. The instantaneous frequency circuitry is configured to determine an instantaneous frequency of the transmit signal. The two-dimensional (2D) bias voltage selection circuitry is configured to determine a bias voltage based on both the instantaneous amplitude and the instantaneous frequency of the transmit signal, and control power supply circuitry to supply the determined bias voltage to a power amplifier that is configured to amplify the transmit signal.

A fully integrated power amplifier (PA) employing a transformer combiner with enhanced back-off efficiency includes a first PA to amplify a first radio frequency (RF) signal and a second PA to amplify a second RF signal. A first variable capacitor is coupled between differential output nodes of the first PA. A second variable capacitor is coupled between differential output nodes of the second PA. The differential outputs of the first PA and the second PA are coupled via respective first and second transformers to a load. Capacitance values associated with the first and second variable capacitors are dynamically adjustable based on an amplitude of the RF signal to achieve a desired power efficiency at an output power level.

A transmitter comprising a power amplifier, a phase modulator, a switched DC-DC converter, all operating in dual mode, and a controller is disclosed. The power amplifier is arranged to selectively operate either in a first mode or in a second mode, wherein the first mode is a linear mode and the second mode is a non-linear mode in order to save power with least increasing cost in hardware. The transmitter is adapted to operate at different allocated bandwidths, for different radio standards while keeping minimum power consumption governed by the controller. A transceiver, a communication device, a method and a computer program are also disclosed.

A linear amplifier is provided to have higher efficiency for an envelope tracking modulator. In one embodiment, a first stage amplifier circuit can be simply operated in a high gain mode or a high bandwidth mode for different applications, without using large chip area. In another embodiment, an output stage has a cascode structure whose dynamic range is controlled according to a voltage level of a supply voltage, to make a core device within the output stage have better protection and suitable dynamic range.

Circuitry that includes a radio frequency (RF) power amplifier (PA) and a dynamic supply boosting circuit, is disclosed. The RF PA receives and amplifies an RF input signal to provide an RF transmit signal using a PA power supply voltage. The dynamic supply boosting circuit provides the PA power supply voltage using a dynamic supply input voltage, wherein when a peak-to-average (PAR) of the RF input signal exceeds a PAR threshold, the dynamic supply boosting circuit boosts the PA power supply voltage, such that the PA power supply voltage is greater than the dynamic supply input voltage.

Embodiments of the disclosure generally relate to a method and device for improving the efficiency of a power amplifier. The apparatus comprising: a harmonic generator, configured to generate one or more harmonic according to an output signal of a power amplifier; a harmonic feedback device, configured to inject the harmonic generated by the harmonic generator to an input terminal of the power amplifier; and a harmonic eliminator, configured to eliminate the harmonic in the output signal of the power amplifier. According to embodiments of the disclosure, the efficiency of power amplifier can be improved without degrading the linearity.

Circuits and methods for reducing the cost and/or power consumption of a user terminal and/or the gateway of a telecommunications system (550) that may include a telecommunications satellite. Embodiments generate a dynamic input bias signal based upon an information signal envelope (which may be pre-distorted) which is applied to the signal input of a power amplifier (PA), thus reducing average power consumption. Other embodiments further include dynamic linearization (518) of the information signal, and/or variation of the supply voltage to the power amplifier (PA) as a function of the envelope of the information signal. Another aspect is a multi-stage chained feedback regulated voltage supply circuit for providing two or more output voltages that may be used as alternative supply voltages to a power amplifier (PA).

A wideband envelope tracking power amplifier includes a plurality of low dropout voltage regulators (LDOs) including at least a first LDO and a second LDO. The wideband envelope tracking power amplifier also includes a single-input-multi-output (SIMO) voltage supply to output a plurality of voltage signals at different voltage levels, the voltage levels including a highest voltage level and one or more voltage levels lower than the highest voltage level. The SIMO voltage supply connects a first of the plurality of voltage signals at a first voltage level to the first LDO to form at least a portion of an envelope tracking voltage level signal, and connects a second of the plurality of voltage signals at a second voltage level less than or equal to the first voltage level to the second LDO to form at least another portion of the envelope tracking voltage level signal.

A power amplifier circuit includes an amplifier element that amplifies a signal input to a base and outputs an amplified signal from a collector, and a variable capacitor provided between the base and the collector of the amplifier element. A power-supply voltage that varies in accordance with an envelope of amplitude of a radio-frequency signal is applied to the collector of the amplifier element, and capacitance of the variable capacitor decreases in response to an increase in the power-supply voltage input to the collector of the amplifier element

A transmitting device including: a modem configured to generate a baseband signal and an envelope data corresponding to the baseband signal; a supply modulator including a first switched-mode power supplier and a second switched-mode power supplier, the supply modulator configured to provide a modulated voltage to an output node based on the envelope data; and a power amplifier configured to amplify a carrier wave signal by using the modulated voltages, the carrier wave signal being associated with the baseband signal, wherein the first switched-mode power supplier includes: a pulse input node to receive a pulse signal generated in association with the envelope data; and a plurality of stages sequentially connected between the pulse input node and the output node, the plurality of stages configured to adjust the modulated voltage by filtering certain frequency band of the pulse signal, and the plurality of stages includes at least one variable impedance.