Abstract: There is disclosed an amplifier arrangement comprising a plurality of amplifiers each arranged to amplify one of a plurality of different input signals, the arrangement comprising an envelope tracking modulator for generating a common power supply voltage for the power amplifiers, and further comprising an envelope selector adapted to receive a plurality of signals representing the envelopes of the plurality of input signals, and adapted to generate an output envelope signal representing the one of the plurality of envelopes having the highest level at a particular time instant as the input signal for the envelope tracking modulator.

Abstract: There is provided an amplification stage including an envelope tracking modulated supply for tracking a reference signal, comprising a low frequency path for tracking low frequency variations in the reference signal and for providing a first output voltage, and a high frequency path for tracking high frequency variations in the reference signal and for providing a second output voltage, and a combiner for combining the first and second output voltages to provide a third output voltage, the amplification stage further comprising a first amplifier arranged to receive the first output voltage as a supply voltage, and a second amplifier arranged to receive the third output voltage as a supply voltage, wherein the first and second amplifiers are enabled in different modes of operation.

Abstract: There is disclosed a multi-stage amplifier comprising: a first amplifier stage; a second amplifier stage; a first voltage supply stage arranged to provide a supply voltage to the first amplifier in dependence on an average power of a signal to be amplified; and a second voltage supply stage arranged to provide a supply voltage to the second amplifier in dependence on an instantaneous power of a signal to be amplified.

Abstract: An amplification stage comprising: an input scaling block for scaling an input signal based on an input scaling factor to generate a scaled version of the input signal; a power amplifier for receiving the scaled version of the input signal and for generating an amplified version of said signal; an envelope detector for generating a signal representing the envelope of the input signal; an envelope scaling block for scaling the envelope signal based on an envelope scaling factor to generate a scaled version of the envelope signal; a non-linear mapping block for generating a voltage representative of the supply voltage based on the scaled envelope signal; a modulator for generating a power supply voltage for the amplifier based on the voltage generated by the non-linear mapping block; and a power control block for maintaining a linear relationship between the envelope scaling factor and the input scaling factor.

Abstract: In accordance with the invention there is also provided a voltage combiner comprising: a transformer having a first and second winding each having a first and second tap; and an inductor connected between the first and second taps of the second winding, wherein: the first tap of the first winding is adapted for connection to a first voltage, the first tap of the second winding is adapted for connection to a second voltage, and the second tap of the second winding is adapted to provide an output being the first and second voltages combined, and further wherein: the inductor is adapted to provide a bypass path for the current associated with the second voltage.

Abstract: There is disclosed a multi-stage amplifier comprising: a first amplifier stage; a second amplifier stage; a first voltage supply stage arranged to provide a supply voltage to the first amplifier in dependence on an average power of a signal to be amplified; and a second voltage supply stage arranged to provide a supply voltage to the second amplifier in dependence on an instantaneous power of a signal to be amplified.

Abstract: There is provided an output stage comprising: a phase splitter for receiving an input signal and for generating first and second drive signals of opposite phase in dependence thereon; a DC offset signal generator for generating a DC offset signal; an adder for adding the DC offset signal to the first drive signal to provide a first modified drive signal; a subtractor for subtracting the DC offset signal from the second drive signal to provide a second modified drive signal; a first drive transistor associated with a first power supply voltage, for generating a first output signal in dependence on the first modified drive signal; a second drive transistor associated with a second power supply voltage, for generating a second output signal in dependence on the second modified drive signal; and a combiner for combining the first and second output signals to generate a phase combined output signal.

Abstract: There is provided an amplification stage comprising: an input scaling block for scaling an input signal in dependence on an input scaling factor to generate a scaled version of the input signal; a power amplifier for generating an amplified version of the scaled input signal; an envelope detector for generating a signal representing the envelope of the input signal; an envelope scaling block for scaling the envelope signal in dependence on an envelope scaling factor to generate a scaled version of the envelope signal; a non-linear mapping block for generating a voltage representative of the supply voltage in dependence on the scaled envelope signal; a modulator for generating a power supply voltage for the amplifier in dependence on the voltage generated by the non-linear mapping block; and a power control block for maintaining a linear relationship between the envelope scaling factor and the input scaling factor.

Abstract: There is disclosed a power supply stage, and a corresponding method, comprising: a plurality of amplifiers for amplifying an input signal, each amplifier receiving a power supply voltage; a common selection means for selecting one of a plurality of power supply voltages in dependence on a reference signal representing a desired power supply voltage; and a plurality of adjusting means, corresponding to the plurality of amplifiers, adapted to generate an adjusted selected power supply voltage for a respective amplifier tracking the reference signal in dependence on the one selected power supply voltage and the reference signal.

Abstract: There is disclosed an envelope tracked power supply comprising a high bandwidth, low delay closed loop switch mode power supply stage comprising: a pulse width modulator for generating a width modulated pulse in dependence on an input signal and an output voltage of the switch mode power supply stage; a wideband transformer, having a winding of a first side connected to receive the modulated pulse, and a winding of a second side; and an output stage connected to the winding of the second side of the transformer, and for generating the output voltage in dependence on the modulated pulse induced in the winding of the second side.

Abstract: There is provided an output stage comprising: a phase splitter for receiving an input signal and for generating first and second drive signals of opposite phase in dependence thereon; a DC offset signal generator for generating a DC offset signal; an adder for adding the DC offset signal to the first drive signal to provide a first modified drive signal; a subtractor for subtracting the DC offset signal from the second drive signal to provide a second modified drive signal; a first drive transistor associated with a first power supply voltage, for generating a first output signal in dependence on the first modified drive signal; a second drive transistor associated with a second power supply voltage, for generating a second output signal in dependence on the second modified drive signal; and a combiner for combining the first and second output signals to generate a phase combined output signal.

Abstract: There is disclosed a power supply stage, and a corresponding method, comprising: a plurality of amplifiers for amplifying an input signal, each amplifier receiving a power supply voltage; a common selection means for selecting one of a plurality of power supply voltages in dependence on a reference signal representing a desired power supply voltage; and a plurality of adjusting means, corresponding to the plurality of amplifiers, adapted to generate an adjusted selected power supply voltage for a respective amplifier tracking the reference signal in dependence on the one selected power supply voltage and the reference signal.

Abstract: There is disclosed an arrangement comprising: a driver stage connected to receive an input signal and generate a drive signal; a transformer comprising: a first winding of a first side of the transformer, across which winding a voltage signal is developed in dependence on the drive signal; and a second winding of the first side of the transformer, coupled to the first winding, which exhibits across it a voltage signal related to the voltage across the first winding, by swingback; and a first controller for comparing the voltage exhibited in the second winding to a first threshold voltage, and for selecting a first or a second supply voltage for the arrangement in dependence on the comparison.

Abstract: There is disclosed an amplifier arrangement comprising a plurality of amplifiers each arranged to amplify one of a plurality of different input signals, the arrangement comprising an envelope tracking modulator for generating a common power supply voltage for the power amplifiers, and further comprising an envelope selector adapted to receive a plurality of signals representing the envelopes of the plurality of input signals, and adapted to generate an output envelope signal representing the one of the plurality of envelopes having the highest level at a particular time instant as the input signal for the envelope tracking modulator.

Abstract: There is disclosed a power supply stage, and a method of controlling such, comprising: a means for generating an intermediate supply signal in dependence on a reference signal representing a desired power supply; and a plurality of adjusting means, each adapted to generate an adjusted supply signal tracking the reference signal, in dependence on the generated intermediate supply signal and the reference signal.

Abstract: This is disclosed an amplification stage including a first amplifier stage, a second amplifier stage, and a power supply unit, in which the output of the first stage provides the input to the second stage, and the power supply unit provides a power supply for both amplifier stages, wherein the voltage of the power supply is continuously varied in dependence of the amplitude of the signal being amplified.

Abstract: There is provided an amplification stage comprising: an input scaling block for scaling an input signal in dependence on an input scaling factor to generate a scaled version of the input signal; a power amplifier for generating an amplified version of the scaled input signal; an envelope detector for generating a signal representing the envelope of the input signal; an envelope scaling block for scaling the envelope signal in dependence on an envelope scaling factor to generate a scaled version of the envelope signal; a non-linear mapping block for generating a voltage representative of the supply voltage in dependence on the scaled envelope signal; a modulator for generating a power supply voltage for the amplifier in dependence on the voltage generated by the non-linear mapping block; and a power control block for maintaining a linear relationship between the envelope scaling factor and the input scaling factor.

Abstract: There is provided an output stage comprising: a phase splitter for receiving an input signal and for generating first and second drive signals of opposite phase in dependence thereon; a DC offset signal generator for generating a DC offset signal; an adder for adding the DC offset signal to the first drive signal to provide a first modified drive signal; a subtractor for subtracting the DC offset signal from the second drive signal to provide a second modified drive signal; a first drive transistor associated with a first power supply voltage, for generating a first output signal in dependence on the first modified drive signal; a second drive transistor associated with a second power supply voltage, for generating a second output signal in dependence on the second modified drive signal; and a combiner for combining the first and second output signals to generate a phase combined output 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: 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.