Patents Assigned to Nujira Limited
  • Publication number: 20140028370
    Abstract: There is disclosed a method of controlling an input to an envelope modulated power supply of an envelope tracking amplification stage, comprising: generating an envelope signal representing the envelope of a signal to be amplified; applying a shaping function to the envelope signal to generate a shaped envelope signal, including: clipping the shaped envelope signal at high input envelope values; and providing the shaped envelope signal as an input signal to the envelope modulated power supply.
    Type: Application
    Filed: January 16, 2013
    Publication date: January 30, 2014
    Applicant: NUJIRA LIMITED
    Inventor: Nujira Limited
  • Publication number: 20140028392
    Abstract: There is disclosed a method of controlling an envelope tracking amplification stage comprising an envelope modulated power supply, the method comprising: determining a shaping function to be applied to an envelope signal for controlling the envelope modulated power supply in dependence on a system linearity objective in a region of operation of the amplifier in which the output power of the amplifier is dependent upon the supply voltage; and determining a pre-distortion function to be applied to an input signal to be amplified in dependence on a further linearity objective of the system, in a region of operation of the amplifier in which the output of the amplifier is dependent upon the input power to the amplifier.
    Type: Application
    Filed: January 16, 2013
    Publication date: January 30, 2014
    Applicant: NUJIRA LIMITED
    Inventor: NUJIRA LIMITED
  • Publication number: 20130321081
    Abstract: There is described an amplification stage comprising: a current mirror circuit comprising a reference transistor arranged to receive a current associated with an input signal and an output transistor providing a current source for an output signal line; a current sink to the output signal line, under the control of the input signal; circuitry arranged to maintain equality between the drain/collector voltages on the transistors of the current mirror circuit.
    Type: Application
    Filed: May 30, 2012
    Publication date: December 5, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Russell Fagg
  • Publication number: 20130321085
    Abstract: There is provided a bias arrangement for an amplifier adapted to amplify a varying input signal, the arrangement comprising a control circuit arranged to adaptively vary a bias current to the amplifier in dependence on an envelope of the varying input signal.
    Type: Application
    Filed: May 30, 2012
    Publication date: December 5, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Russell Fagg
  • Patent number: 8587379
    Abstract: A power amplifier circuit comprising a transistor for receiving a signal to be amplified at an input and for outputting an amplified signal at an output; a modulated power supply connected to the transistor output; and a resistive element connected at the transistor output such that a low impedance is maintained at the transistor output across a range of operational frequencies.
    Type: Grant
    Filed: January 30, 2012
    Date of Patent: November 19, 2013
    Assignee: Nujira Limited
    Inventor: Martin Paul Wilson
  • Publication number: 20130300513
    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.
    Type: Application
    Filed: July 12, 2013
    Publication date: November 14, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Martin Paul Wilson
  • Patent number: 8570105
    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.
    Type: Grant
    Filed: February 14, 2012
    Date of Patent: October 29, 2013
    Assignee: Nujira Limited
    Inventors: Gerard Wimpenny, Robert Henshaw
  • Publication number: 20130241650
    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.
    Type: Application
    Filed: April 3, 2013
    Publication date: September 19, 2013
    Applicant: Nujira Limited
    Inventor: Gerard Wimpenny
  • Publication number: 20130222057
    Abstract: There is disclosed a method of generating a supply voltage (230) for a power amplifier (114) arranged to amplify an input signal (228), comprising: generating (104) a target supply voltage tracking the input signal (228); predistorting (400) the target supply voltage to compensate for effects on a supply voltage in the amplifier (114); and generating (102) the supply voltage for the amplifier (114) in dependence on the predistorted target supply voltage (414).
    Type: Application
    Filed: May 26, 2011
    Publication date: August 29, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Robert Henshaw
  • Patent number: 8514018
    Abstract: There is disclosed a method for determining the timing misalignment between a power supply and an output in an envelope tracking amplification stage, the method including the steps of: estimating a distortion parameter in the amplification stage; and determining a timing error in dependence on the estimated distortion parameter.
    Type: Grant
    Filed: March 30, 2011
    Date of Patent: August 20, 2013
    Assignee: Nujira Limited
    Inventor: Shaun Cummins
  • Publication number: 20130207724
    Abstract: There is provided an amplifier arrangement comprising a main push pull amplifier (100) connected to receive an input signal and generate an amplified version of the input signal and an additional amplifier (624) that is a scaled down version of the main push pull amplifier. The main push pull amplifier (100) and the additional amplifier (624) are coupled in parallel to receive an input signal (122) and generate an amplified output signal (114), wherein the amplifier arrangement comprises optionally a high-pass filter (622) between the overall amplifier input (122) and the input of the additional amplifier (624). In order to reduce crossover distortions generated by the main push pull amplifier, the additional amplifier is designed to amplify the input signal during crossover, thus the output signal always follows the input signal.
    Type: Application
    Filed: June 13, 2011
    Publication date: August 15, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Martin Paul Wilson
  • Publication number: 20130200949
    Abstract: There is disclosed a method, in an amplifier stage comprising an amplifier and a modulated supply, the amplifier being arranged to amplify an input signal and the modulated supply being arranged to generate a supply voltage for the amplifier by tracking an envelope of the signal to be amplified, the method comprising: comparing the relative timing of a signal representing the current drawn by the amplifier from the modulated supply and a signal representing the voltage generated at the output of the modulated supply; and in dependence upon a difference in the relative timing, adjusting the timing of either the input signal to be amplified or the generated supply voltage to reduce the difference in the relative timing.
    Type: Application
    Filed: April 12, 2011
    Publication date: August 8, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Martin Paul Wilson
  • Publication number: 20130200865
    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.
    Type: Application
    Filed: August 15, 2011
    Publication date: August 8, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Gerard Wimpenny
  • Publication number: 20130193943
    Abstract: There is disclosed a switching stage comprising: a first switching path having at least one switching element for selectively connecting an input of the switching stage to an output of the switching stage; and a second switching path having at least one switching element for selectively connecting the input of the switching stage to the output of the switching stage, wherein the first and second switching paths are controlled such that a signal is selectively routed from the input of the switching stage to the output of the switching stage via the first and second switching paths in dependence on the current of the signal to be routed.
    Type: Application
    Filed: May 24, 2011
    Publication date: August 1, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Martin Paul Wilson
  • Patent number: 8482322
    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.
    Type: Grant
    Filed: February 14, 2012
    Date of Patent: July 9, 2013
    Assignee: Nujira Limited
    Inventors: Gerard Wimpenny, Martin Paul Wilson
  • Patent number: 8476976
    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.
    Type: Grant
    Filed: April 9, 2009
    Date of Patent: July 2, 2013
    Assignee: Nujira Limited
    Inventor: Gerard Wimpenny
  • Publication number: 20130141165
    Abstract: There is provided an integrated circuit comprising a main push-pull amplifier (108, 110) with balanced outputs and an additional push-pull amplifier (862, 863) with balanced outputs. Each of these balanced outputs is connected to an off-chip load (822) via respective bonding wires (818, 828, 830, 880) to provide a combined amplified signal to the load. The additional amplifier serves to compensate for crossover distortions generated by the main amplifier.
    Type: Application
    Filed: June 13, 2011
    Publication date: June 6, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Martin Paul Wilson
  • Publication number: 20130127547
    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.
    Type: Application
    Filed: March 29, 2011
    Publication date: May 23, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Gerard Wimpenny
  • Publication number: 20130049858
    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.
    Type: Application
    Filed: June 22, 2012
    Publication date: February 28, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Gerard Wimpenny
  • Publication number: 20130002346
    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.
    Type: Application
    Filed: November 25, 2010
    Publication date: January 3, 2013
    Applicant: NUJIRA LIMITED
    Inventor: Gerard Wimpenny