Abstract: A distributed envelope tracking (ET) amplifier circuit and related apparatus are provided. The distributed ET amplifier apparatus includes an amplifier circuit configured to amplify a radio frequency (RF) signal based on a modulated voltage. In examples discussed herein, the amplifier circuit is co-located with an ET voltage circuit configured to supply the modulated voltage such that a trace inductance between the amplifier circuit and the ET voltage circuit can be reduced to below a defined threshold. By co-locating the amplifier circuit with the ET voltage circuit to reduce a coupling distance between the amplifier circuit and the ET voltage circuit and thus the trace inductance associated with the coupling distance, it may be possible to reduce degradation in the modulated voltage. As a result, it may be possible to improve efficiency and maintain linearity in the amplifier circuit, particularly when the RF signal is modulated at a higher modulation bandwidth.

Abstract: A method for increasing efficiency of a radio frequency (RF) amplifier employing laterally diffused metal oxide semiconductor (LDMOS) transistors coupled to an RF exciter including determining an emission mode of modulated RF input signals generated by the exciter, if the emission mode is of a type where the modulated RF input signals have a continuously varying envelope, biasing the LDMOS transistors in the RF amplifier for linear operation, and if the emission mode is of a type where the modulated RF input signals do not have a continuously varying envelope, biasing the LDMOS transistors in the RF amplifier with a fixed quiescent drain current and a fixed drain supply voltage for the LDMOS transistors selected to cause the LDMOS transistors to operate in compression.

Abstract: A secondary side controller for a switched mode power supply, the controller comprising a first semiconductor die comprising an integrated circuit configured to provide a load connection signal; a second semiconductor die, packaged with the first semiconductor die, comprising a charge pump configured to, in response to the load connection signal received from the integrated circuit of the first semiconductor die, provide a switch signal for control of a load connection switch that controls whether or not the switched mode power supply is electrically connected to a load; wherein the presence or absence of the load connection signal is configured to control whether or not the charge pump generates the switch signal and the amplitude of the load connection signal is configured to control the voltage of the switch signal.

Abstract: A linearizer comprises a delay compensation circuit, an envelope reshaping circuit and a phase shift unit. The delay compensation circuit is configured to delay an input signal and to output a delayed input signal to a power amplifier. The envelope reshaping circuit is configured to detect an envelope of the input signal and to generate a reshaped envelope signal. The phase shift unit configured to provide an envelope reshaped capacitance based on the reshaped envelope signal to the delayed input signal to reshape the delayed input signal.

Abstract: A power supply system controls output powers of a plurality of power supply apparatus for realizing optimal conversion efficiency between input power and output power. The power supply system includes a plurality of power conversion units that convert an input power supplied from the input side into an output power for supplying the output power to a load connected to the output side; a power measurement unit that measures the output power of the power conversion unit; and a power supply control unit that calculates the input power to the power conversion unit in response to the output power of the power conversion units measured by the power measurement unit, and calculates the output power of the power conversion unit realizing the minimum calculated input power as an optimal output power, and controls the power conversion units based on the calculated optimal output power.

Abstract: Is provided a power supply system optimizing a power conversion efficiency of its entire system, including at least one main power supply unit converting an input power into an output power supplied to a load; an auxiliary power supply unit including a power storage unit supplying an output power by the power storage unit to the load; a power measurement unit for measuring an output power from the main and auxiliary power supply units; and a power supply control unit for calculating an optimal output power in the main power supply unit maximizing its power conversion efficiency according to the output power measured by the power measurement unit and an optimal output power or charge power in the auxiliary power supply unit, controlling the main power supply unit based on the optimal output power, and controlling the auxiliary power supply unit based on the optimal output power or charge power.

Abstract: A system and method for modulating the sound pressure that is output from an audio transducer is disclosed. In one embodiment, the method includes receiving an audio signal and placing the audio signal across a voice coil of the transducer. In addition, a voltage is applied across a field coil of the transducer, the field coil being separate from the voice coil. And the voltage that is applied across the field coil is adjusted so as to modulate the sound pressure output from the audio transducer.

Abstract: A method and an apparatus for controlling a transmit signal of a radio frequency power amplifier are provided. The method includes: adjusting a power supply voltage of the power amplifier to an efficiency point power supply voltage under designated transmit power; querying correspondence between an input voltage and transmit power at each power level under the efficiency point power supply voltage; and adjusting, according to the correspondence, an input voltage to an input voltage corresponding to the designated transmit power. The embodiments of the present invention, the power amplifier is enabled to work at an optimum efficiency point while the transmit power of the power amplifier is under control, which improves efficiency of the power amplifier.

Abstract: A radio frequency amplification stage comprising: an amplifier for receiving an input signal to be amplified and a power supply voltage; and a power supply voltage stage for supplying said power supply voltage, comprising: means for providing a reference signal representing the envelope of the input signal; means for selecting one of a plurality of supply voltage levels in dependence on the reference signal; and means for generating an adjusted selected power supply voltage, comprising an ac amplifier for amplifying a difference between the reference signal and one of the selected supply voltage level or the adjusted selected supply voltage level, and a summer for summing the amplified difference with the selected supply voltage to thereby generate the adjusted supply voltage.

Abstract: A fast tracking power supply device, a fast tracking power supply control method, and communication equipment are provided. The fast tracking power supply device includes: a basic voltage output unit, configured to output a basic voltage; a basic current unit, configured to output a basic current; a linear amplifier, configured to output a compensation current and a compensation voltage, the linear amplifier is connected in parallel with the basic current output unit, and then is connected in series with the basic voltage output unit. The device can output signal with high efficiency and bandwidth.

Abstract: There is disclosed a power supply stage, comprising: generating means for generating a power supply voltage from a high efficiency variable voltage supply in dependence on a reference signal; adjusting means for receiving the generated power supply voltage, and adapted to provide an adjusted selected power supply voltage tracking the reference signal in dependence thereon.

Abstract: A radio frequency amplification stage comprising: an amplifier for receiving an input signal to be amplified and a power supply voltage; and a power supply voltage stage for supplying said power supply voltage, comprising: means for providing a reference signal representing the envelope of the input signal; means for selecting one of a plurality of supply voltage levels in dependence on the reference signal; and means for generating an adjusted selected power supply voltage, comprising an ac amplifier for amplifying a difference between the reference signal and one of the selected supply voltage level or the adjusted selected supply voltage level, and a summer for summing the amplified difference with the selected supply voltage to thereby generate the adjusted supply voltage.

Abstract: A power conversion circuit includes a pulse width modulator, a feedback module, a negative voltage producing module, a voltage regulating module, a path switch, and a rectifier module. The path switch is connected to a power port connected to a power source. The feedback module produces a feedback signal according to the voltage of a positive voltage input port of a power amplifier. The pulse width modulator receives the feedback signal, and outputs a pulse signal with a corresponding duty cycle according to the feedback signal to the path switch, then producing a switching power supply signal; the rectifier module converts the switching power supply signal to a direct current signal with a suitable positive voltage. The negative voltage producing module produces corresponding negative voltage when the path switch is turned on or off. The voltage regulating module regulates the negative voltage to a suitable negative voltage.

Abstract: Apparatus and methods for reducing output noise of a signal channel are provided. In one embodiment, a signal channel includes an amplifier for amplifying an input signal to generate an amplified signal. The amplifier includes a bias circuit that controls a bias current of the amplifier based on a voltage across a biasing capacitor. The apparatus further includes a sampling circuit for sampling the amplified signal. The sampling circuit generates an output signal based on a difference between a first sample of the amplified signal taken at a first time instance and a second sample of the amplified signal taken at a second time instance. The bias circuit samples a bias voltage onto the biasing capacitor before the first time instance and holds the voltage across the biasing capacitor substantially constant between the first time instance and the second time instance to reduce noise of the output signal.

Abstract: A high-frequency module including a power amplifying circuit includes a high-frequency power amplifying element, a matching circuit, and a driving power-supply circuit. The high-frequency power amplifying element includes a high-frequency amplifying circuit and a directional coupler. A first end of a main line of the directional coupler is connected to an output terminal of a latter-stage amplifying circuit of the high-frequency amplifying circuit. A second end of the main line of the directional coupler is connected through an output matching circuit to a high-frequency signal output terminal of the high-frequency power amplifying element. The output terminal of the latter-stage amplifying circuit is also connected to a second driving power-supply voltage application terminal of the high-frequency power amplifying element. The second driving power-supply voltage application terminal is connected to the high-frequency signal output terminal by a connecting conductor.

Abstract: A power supply is disclosed herein. For example, the power supply can include a switching device and an aperture generator and control module. The switching device can be configured to down-convert an input voltage and pass the down-converted input voltage to an output voltage node. The aperture generator and control module can be configured to control the switching device. In response to a power efficiency of the power supply exceeding a predetermined threshold, the aperture generator and control module can deactivate the switching device and pass the input voltage to the output voltage node.

Abstract: There is provided an amplifier apparatus and a signal processing apparatus that reduce a delay or distortion of a power supply voltage used for drain modulation. An amplifier apparatus is an amplifier apparatus that performs drain modulation, and includes a printed circuit board having a first surface and a second surface; an amplifier circuit disposed on the first surface; and a modulation power supply circuit that supplies a variable power supply voltage for performing drain modulation, to the amplifier circuit. The modulation power supply circuit has an output portion that outputs the power supply voltage. The amplifier circuit has an input portion to which the power supply voltage is supplied. The output portion is located on the side of the second principal surface of the printed circuit board and is connected to the input portion through a conductor penetrating through the printed circuit board.

Abstract: An exemplary embodiment of an analog multiplier may include a voltage controlled resistance circuit, a first transistor and a second transistor, where the resistance of the voltage controlled resistance circuit is based upon a difference between a supply voltage and a first input voltage and a constant current supply. The current passing through the voltage controlled resistance circuit is based upon a difference between the voltage supply and a second input voltage. The first transistor may be configured to mirror the current passing through the voltage controlled resistance circuit.

Abstract: Method and apparatus for automatically controlling the operation of a DC power enhancement circuitry connected to an RF power amplifier (PA) that operates at various input signal levels, according to which the instantaneous magnitude of the input signal is sensed and the instantaneous magnitude and its highest (lowest) peak are stored. For the time period during which the peak remains the highest (lowest) peak, the desired dynamic range of the power amplifier is determined according to the peak and a corresponding threshold level and the gain of the enhancement circuitry are determined according for that time period. Whenever the magnitude exceeds the corresponding threshold level, the enhancement circuitry provides to the power amplifier a level of DC power enhancement required for maintaining the output power of the power amplifier within the output dynamic range.

Abstract: A computer controlled amplifier and speaker system includes a power conservation feature allowing ready adaptation to a variety of consumer vehicles, audio systems, and individual consumer purposes. The computer controlled amplifier and speaker system includes an audio-signal detection and power on/off feature and accepts multiple audio inputs and enables multiple audio outputs while also allowing ready adaptation to a variety of power sources. A plurality of power supply functions are readily adapted to supply power to the amplifier and speaker system enhancing user convenience. The disclosed system may be readily adaptable to a portable kit allowing achievement of similar power conservation goals in diverse settings.

Abstract: Methods and systems for enhancing system efficiency in a power amplification, modulation, and transmission system are provided. Embodiments include determining output power characteristics of a selected modulation scheme to be employed in data transmission, determining a most probable output power point of operation for the selected modulation scheme based on the output power characteristics, and controlling the output stage power supply of the system to operate at substantially optimal efficiency at the most probable output power point of operation.

Abstract: A radio frequency amplification stage comprising: an amplifier for receiving an input signal to be amplified and a power supply voltage; and a power supply voltage stage for supplying said power supply voltage, comprising: means for providing a reference signal representing the envelope of the input signal; means for selecting one of a plurality of supply voltage levels in dependence on the reference signal; and means for generating an adjusted selected power supply voltage, comprising an ac amplifier for amplifying a difference between the reference signal and one of the selected supply voltage level or the adjusted selected supply voltage level, and a summer for summing the amplified difference with the selected supply voltage to thereby generate the adjusted supply voltage.

Abstract: The present invention discloses a multi-voltage headphone driver circuit comprising: at least one operational amplifier having an output supplied to a headphone speaker, the operational amplifier receiving a first power supply as its high operation voltage; a charge pump receiving a second power supply to generate a negative voltage corresponding to the second power supply in magnitude; and an m-fold circuit multiplying the negative voltage by m and providing the result to the operational amplifier as a low operation voltage thereof, wherein m is a real number.

Abstract: Circuits and methodologies related to high-voltage tolerant regulators are disclosed. In some implementations, a voltage regulator can be configured to be capable of being in a regulating state and a bypass state. In the regulating state, an input voltage greater than a selected value can be regulated so as to yield a desired output voltage such as a substantially constant voltage. In the bypass state, an input voltage at or less than the selected value can be regulated so as to yield an output voltage that substantially tracks the input voltage. Such a capability of switching between two modes can provide advantageous features such as reducing the likelihood of damage in a powered circuit due to high input voltage, and extending the operating duration of a power source such as a rechargeable battery. Also disclosed are examples of how the foregoing features can be implemented in different products and methods of operation and fabrication.

Abstract: An amplifier circuit (100) has an input stage (OP1) and an output stage (Q1, Q2) operating with different supply voltages and different quiescent voltages. The output stage has a feedback input connected to receive a feedback signal from the output of the output stage. A biasing circuit (602) applies a bias signal (Ioff) to said input stage at an operating level appropriate to establish a quiescent output voltage different from a ground reference level of the input stage.

Abstract: A method and apparatus for controlling a selectable voltage audio power output stage provides a mechanism for raising the selected power amplifier output voltage in time for the arrival of signal peaks to avoid clipping. Signal peaks may either be delayed by delaying an increase in volume control level or enabling signal compression for a predetermined time period, so that sufficient time is provided for the amplifier power supply to stabilize at a higher operating voltage when an increase of power supply voltage is selected. Alternatively, a signal level may be determined at an upstream source, such as a decoder or filter that provides information in sufficient advance of the arrival of the peaks, and used to control the power supply selection, so that the higher power supply voltage level is selected in advance of arrival of the signal peaks that would otherwise cause clipping at the power amplifier output.

Abstract: The solution controls electric operational power to be fed to an amplifier. The control can be carried out, for instance, in accordance with a predetermined signal. The operational power is fed to the amplifier with a voltage source unit and a current source unit, and the operational voltage that the voltage source unit feeds to the amplifier is controlled. The current source unit feeds at least some of the operational electric current of the amplifier.

Abstract: A system and method for modulating the sound pressure that is output from an audio transducer is disclosed. In one embodiment, the method includes receiving an audio signal and placing the audio signal across a voice coil of the transducer. In addition, a voltage is applied across a field coil of the transducer, the field coil being separate from the voice coil. And the voltage that is applied across the field coil is adjusted so as to modulate the sound pressure output from the audio transducer.

Abstract: A power circuit for a power amplifier which operates in an inactive period and an active period is provided and includes a power supply unit, a current limiting unit, a storage unit, and a converting unit. The power supply unit provides a first current. The current limiting unit is arranged to process the first current to generate a second current. The storage unit is arranged to provide a storage voltage. The storage unit is charged by the second current during the inactive period and discharged by a third current during the active period. The converting unit provides an active power to the power amplifier according to the storage voltage, the second current, and the third current during the active period.

Abstract: A piezoelectric buzzer driving circuit (200) for driving a piezoelectric buzzer (211) with two terminals includes a reverser (216). The reverser includes an output terminal and an input terminal (24) configured for receiving a controlling signal to control an output of the reverser. The two terminals of the piezoelectric buzzer respectively connected to the input terminal and the output terminal such that a D-value of the voltage across the piezoelectric buzzer is twice as large as the voltage of the controlling signal.

Abstract: Systems and method to compress digital video based on human factors expressed as a desirability score are provided. A particular method includes passing a digital input signal through a pulse-width modulator and passing an output of the pulse-width modulator through a power switching device. An output of the power switching device has a plurality of pulses. The method includes receiving the output of the power switching device at a first input of a comparator and receiving a reference voltage at a second input of the comparator. The method includes determining a net signal based on an output of the comparator and determining a timing error signal based on the net signal and the digital input signal. The method also includes adjusting the digital input signal to compensate for harmonic distortion based at least in part on the timing error signal.

Abstract: An analog error amplifier includes an amplifier circuit and a replica bias circuit that together produce an output signal representing a difference between an input signal and a reference signal. The amplifier circuit produces the output signal in response to the input signal and a bias signal provided by the replica bias circuit. The bias signal may establish a reference threshold of a basic amplifier in the amplifier circuit. The replica bias circuit produces the bias signal in response to the reference signal and drives the bias signal to be equal to the reference signal. The replica bias circuit may include a plurality of amplifier stages. The bias signal produced by a single replica bias circuit may be provided to a plurality of amplifier circuits to provide a plurality of error amplifiers for a single reference signal.

Abstract: A distributed power converter is for use with an RF power amplifier and includes a primary converter connected to an input voltage and configured to provide a regulated DC intermediate voltage that is galvanically isolated from the input voltage. Additionally, the distributed power converter also includes a secondary regulator connected galvanically to the regulated DC intermediate voltage and configured to generate a regulated DC supply voltage for at least a portion of the RF power amplifier. In another aspect, a method of operating a distributed power converter is for use with an RF power amplifier and includes providing a regulated DC intermediate voltage that is galvanically isolated from an input voltage and generating a regulated DC supply voltage for at least a portion of the RF power amplifier that is galvanically connected to the regulated DC intermediate voltage.

Abstract: A power circuit for a power amplifier which operates in an inactive period and an active period is provided and includes a power supply unit, a current limiting unit, a storage unit, and a converting unit. The power supply unit provides a first current. The current limiting unit is arranged to process the first current to generate a second current. The storage unit is arranged to provide a storage voltage. The storage unit is charged by the second current during the inactive period and discharged by a third current during the active period. The converting unit provides an active power to the power amplifier according to the storage voltage, the second current, and the third current during the active period.

Abstract: A DC-coupled audio out unit is provided, including at least one regulator and at least one audio amplifier. The regulator is coupled to at least one power terminal of the audio amplifier.

Abstract: A highly efficient power supply, a method for supplying power, and a method for arranging a power supply, for a UHF or microwave radio frequency amplifier intended for operation with a signal that has a power level which varies at a high frequency rate. The power supply has an output for connecting to a power supply input of the radio frequency power amplifier and includes a high rate controllable voltage supply employing electronic linear devices connected to the output, an element for quantifying power dissipated by the electronic linear devices and a low rate controllable current supply connected to the output. Preferably, the current supply is a substantially constant current supply at the frequency of the radio frequency signal. Preferably, the controllable voltage supply has a control input and is arranged to be controlled for outputting a voltage that is a function of the high frequency power variation.

Abstract: Method and apparatus for automatically controlling the operation of a DC power enhancement circuitry connected to an RF power amplifier (PA) that operates at various input signal levels, according to which the instantaneous magnitude of the input signal is sensed and the instantaneous magnitude and its highest (lowest) peak are stored. For the time period during which the peak remains the highest (lowest) peak, the desired dynamic range of the power amplifier is determined according to the peak and a corresponding threshold level and the gain of the enhancement circuitry are determined according for that time period. Whenever the magnitude exceeds the corresponding threshold level, the enhancement circuitry provides to the power amplifier a level of DC power enhancement required for maintaining the output power of the power amplifier within the output dynamic range.

Abstract: There is disclosed a technique for controlling at least one amplification stage, comprising: selecting a linearity objective for the amplification stage; in dependence on an input signal to said amplification stage, determining a combination of supply input and bias input for the amplification stage in order to meet said linearity objective; and in dependence on there being more than one combination of supply input and bias input for meeting the linearity objective, selecting the combination that optimises a further system performance objective for the amplification stage. The further system performance objective may be one or more of: an efficiency objective; an envelope signal bandwidth objective; or a robustness to production tolerance objective.

Abstract: Apparatus includes an equalizer having a signal input, a control input and an output; a controllable power supply having a control input and an output, the input of the controllable power supply being coupled to the output of the equalizer; a power amplifier having a main signal input, a power supply input, and an output, the power supply input being coupled to the output of the controllable power supply; and a controller having first and second inputs and an output, the first input being coupled directly or indirectly to the output of the controllable power supply, the second input being coupled to a node upstream of the equalizer, and the output being coupled to the control input of the equalizer; the equalizer being configured to apply equalisation to an envelope signal received at its input and to provide a resulting equalized envelope signal at its output, the controllable power supply being configured to provide a power signal at its output based on the equalized envelope signal received at its input, t

Abstract: A video circuit including a video amplifier adapted to generate an amplified output video signal from an input video signal; a short detection circuit adapted to generate a first signal indicative of whether there is a short present at an output of the video amplifier; and a load detection circuit adapted to generate a second signal indicative of whether there is a load coupled to the output of the video amplifier. The video circuit may further include an input signal detection circuit adapted to generate a third signal indicative of whether an input video signal is present. The third signal generated by the input signal detection circuit may be used to enable the outputting of the first and second signals in order to prevent the false indication of faults at the output of the video amplifier in the absence of an input video signal.

Abstract: A radio frequency amplifier system is disclosed in which the amplifier bias supply and power supply voltages are >instantaneously modulated with signals derived from the envelope voltage of the input signal. Separate non-linear mapping functions are used to derive the supply and bias voltages. The two mapping functions are optimised jointly to achieve particular system performance goals, such as optimum efficiency, constant gain, constant phase, or minimum spectral spreading. An optimisation of >particular interest is that which achieves best RF amplifier power added efficiency subject to achieving constant amplifier gain. In this way the need for pre-distortion linearization may be reduced or eliminated.

Abstract: A power amplifier using a digitally pre-distorted compound semiconductor transistor is discussed. The amplifier has improved linearity. For a given gate bias voltage, there exists a drain voltage at which the drain current is the same for a pulsed signal as for a DC signal and is invariant to quiescent bias points occurring when a pulsed signal is applied. If an amplifier operates at this point, the trapping effects that lead to memory effects do not affect the dynamic behaviour of a digitally pre-distorted amplifier, resulting in improved linearity. The existence of this point, and it's benefits to the linearity of a digitally pre-distorted amplifier, have not been previously recognised.

Abstract: Circuitry for providing improved pulse-type enhancement of the voltage supplied to a power amplifier (101) that is fed by a power supply that is connected to the power amplifier (101) at a feeding point through a main supply path that is connected via an inductor (L1). A second feeding point is used for enhancement by a capacitor that is discharged. A transformer L2, L3, M) is formed by mutually coupling an additional inductor (L3), through which an additional supply path is connected. Enhancement power is provided partially through the transformer L2, L3, M) and the remaining part thorough the capacitor (C1). This way, the total level of possible enhancement is increased, while minimizing distortion of the envelope of the amplified RF signal.

Abstract: A layout of a power device is provided. The layout includes a substrate, a unit array, a plurality of first, second, third and fourth signal paths, and a first, second, third and fourth port. The unit array with a plurality of rows is disposed on the substrate. Each row of the unit array includes a plurality of units. The first and second signal paths on the substrate are disposed on a first side and a second side of corresponding odd-numbered rows of the unit array. The third and the fourth signal paths on the substrate are disposed above a corresponding row of the unit array. The first to fourth ports on the substrate are electrically connected to the first to fourth signal paths respectively.

Abstract: An integrated circuit device of the present invention includes a plurality of signal processing circuits classified into a plurality of groups, each signal processing circuit including an amplifier circuit for amplifying an input electric signal and a bias circuit having an input terminal connected electrically to a bias source and supplying a bias input terminal of the amplifier circuit with an operation bias for an amplifying operation of the amplifier circuit; and a plurality of connection wirings arranged each for each of the groups separately, such that the input terminals of the bias circuits of the signal processing circuits in one of the groups are commonly connected through the connection wirings. This provides an integrated circuit device suppressing the lowering of an image quality in consideration of enabling lower power consumption, a low noise characteristic, and high integration, and an imaging apparatus using the integrated circuit.

Abstract: A method and device for improving the efficiency of an envelope tracking transmitter in which a power amplifier for coupling modulated signals in a carrier frequency to an antenna for transmission. The transmitter comprises a power supply for providing a supply voltage to the power amplifier, and a computation means for providing a waveform indicative of the envelope of the modulated signal to the power supply in order to modify the supply voltage. A lower limit is imposed to the waveform so that the supply voltage to the power supply is always greater than a predetermined value. Moreover, when information is transmitted in times slots which are started and ended by ramp periods, a constant signal, based on the root-mean-square value of the waveform, is used to modify the waveform so that the supply voltage to the power amplifier includes a constant voltage level in the ramp periods.

Abstract: A radio frequency amplification stage comprising: an amplifier for receiving an input signal to be amplified and a power supply voltage; and a power supply voltage stage for supplying said power supply voltage, comprising: means for providing a reference signal representing the envelope of the input signal; means for selecting one of a plurality of supply voltage levels in dependence on the reference signal; and means for generating an adjusted selected power supply voltage, comprising an ac amplifier for amplifying a difference between the reference signal and one of the selected supply voltage level or the adjusted selected supply voltage level, and a summer for summing the amplified difference with the selected supply voltage to thereby generate the adjusted supply voltage.

Abstract: A power amplifier has a non-linear low power pre-distortion amplifier (112) for transforming a carrier signal (111) to a pre-distorted signal (113) having a carrier component with out-of-phase non-linear distortions, and a non-linear power amplifier (114) having non-linear characteristics similar to a portion of the non-linear low power pre-distortion amplifier for generating from the pre-distorted signal a transmission signal (115) having an amplified carrier component with substantially diminished non-linear distortions.

Abstract: A radio frequency amplification stage including an amplifier for receiving an input signal to be amplified and a power supply voltage; and a power supply voltage stage for supplying said power supply voltage, including a circuit for providing a reference signal representing the envelope of the input signal; a circuit for selecting one of a plurality of supply voltage levels in dependence on the reference signal; and a circuit for generating an adjusted selected power supply voltage, including an ac amplifier for amplifying a difference between the reference signal and one of the selected supply voltage level or the adjusted selected supply voltage level, and a summer for summing the amplified difference with the selected supply voltage to thereby generate the adjusted supply voltage.

Abstract: The present invention, generally speaking, provides for high-efficiency power control of a high-efficiency (e.g., hard-limiting or switch-mode) power amplifier in such a manner as to achieve a desired modulation. In one embodiment, the spread between a maximum frequency of the desired modulation and the operating frequency of a switch-mode DC-DC converter is reduced by following the switch-mode converter with an active linear regulator. The linear regulator is designed so as to control the operating voltage of the power amplifier with sufficient bandwidth to faithfully reproduce the desired amplitude modulation wave-form. The linear regulator is further designed to reject variations on its input voltage even while the output voltage is changed in response to an applied control signal. This rejection will occur even though the variations on the input voltage are of commensurate or even lower frequency than that of the controlled output variation.