USRE42612E1 - Switched-mode power amplifier using lumped element impedance inverter for parallel combining - Google Patents

Switched-mode power amplifier using lumped element impedance inverter for parallel combining Download PDF

Info

Publication number
USRE42612E1
USRE42612E1 US11/787,231 US78723107A USRE42612E US RE42612 E1 USRE42612 E1 US RE42612E1 US 78723107 A US78723107 A US 78723107A US RE42612 E USRE42612 E US RE42612E
Authority
US
United States
Prior art keywords
input
output
component
impedance
inductor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US11/787,231
Inventor
Johan M. Grundingh
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zarbana Digital Fund LLC
Original Assignee
Zarbana Digital Fund LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zarbana Digital Fund LLC filed Critical Zarbana Digital Fund LLC
Priority to US11/787,231 priority Critical patent/USRE42612E1/en
Assigned to ZARBANA DIGITAL FUND LLC reassignment ZARBANA DIGITAL FUND LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ICEFYRE SEMICONDUCTOR, INC.
Assigned to ICEFYRE SEMICONDUCTOR, INC. reassignment ICEFYRE SEMICONDUCTOR, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ICEFYRE SEMICONDUCTOR CORPORATION
Assigned to ICEFYRE SEMICONDUCTOR CORPORATION reassignment ICEFYRE SEMICONDUCTOR CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GRUNDLINGH, JOHAN M.
Application granted granted Critical
Publication of USRE42612E1 publication Critical patent/USRE42612E1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F3/00Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/21Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H03F3/211Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only using a combination of several amplifiers
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F1/00Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/02Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
    • H03F1/0205Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers
    • H03F1/0294Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers using vector summing of two or more constant amplitude phase-modulated signals
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F1/00Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/56Modifications of input or output impedances, not otherwise provided for
    • H03F1/565Modifications of input or output impedances, not otherwise provided for using inductive elements
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F3/00Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/21Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H03F3/217Class D power amplifiers; Switching amplifiers
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F3/00Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/68Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F2200/00Indexing scheme relating to amplifiers
    • H03F2200/391Indexing scheme relating to amplifiers the output circuit of an amplifying stage comprising an LC-network
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F2200/00Indexing scheme relating to amplifiers
    • H03F2200/402A series resonance being added in shunt in the output circuit, e.g. base, gate, of an amplifier stage

Definitions

  • the invention relates to circuitry for radio frequency (i.e. “RF” or “wireless”) transmitters and, in particular, to a switched-mode power amplifier design and configuration for parallel connection with one or more like amplifiers for combining of the signals output therefrom.
  • RF radio frequency
  • power combiners are used in RF transmitters to combine the output signals of parallel power amplifiers into one high power RF output signal for wireless transmission.
  • the signals are first amplified by the power amplifiers and then they are combined by a separate power combiner to produce a combined amplified signal for transmission.
  • a separate power combiner to produce a combined amplified signal for transmission.
  • the need for efficiency is a particularly important design factor for the highly integrated requirements of transceivers used for wireless local area networks (LANs) and employing modulation formats such as OFDM (Orthogonal Frequency Division Multiplex).
  • OFDM Orthogonal Frequency Division Multiplex
  • the assignee of this invention and application has developed signal modulation methods, using OFDM signal format, whereby information signals are deconstructed into independent component signals, these independent signals being more efficiently processed and modulated than the original information signals from which they derive, and then the independent signals are up-converted, amplified and combined prior to transmission.
  • Use of such independent modulated signals presents additional challenges to achieving efficiency at the amplification/combination stages of the transmitter, however, because the conventional model of amplification followed by combining, using known power amplifiers and combiners, is subject to inherent loss and isolation limitations.
  • the Chireix-type power amplifier represents one of the LINC (Linear amplification with Nonlinear Components) architectures and uses linear, saturated, or switch-mode amplifiers to provide amplification for signals having amplitude as well as phase modulation. It operates by adjusting the phase applied to two amplifiers, and combining the outputs through a combiner to reintroduce the amplitude modulation.
  • An appropriate combiner for the Chireix architecture not only reinserts the amplitude modulation to the signal, it also provides a dynamic adjustment of the load impedance presented to each amplifier (out-phasing). This out-phasing adjustment of the load impedances is such that the DC current through each active device decreases as the combined output amplitude decreases, thereby maintaining high efficiency.
  • a Chireix-type amplifier do not provide any isolation between the outputs of the two amplifiers.
  • One example of this is a “pseudo” balanced magnetic transformer (i.e. having no center tap to ground connection) connecting the individual amplifier outputs to the two terminals, Input 1 and Input 2 , of the input winding 100 , as shown in the prior art illustration of FIG. 1 .
  • the magnetic transformer effectively combines, in series, in the output winding 200 , the signals from the individual amplifiers and, for efficiency, the outputs of the individual amplifiers must be low impedance voltage sources.
  • it will be understood by the skilled reader that such use of a magnetic transformer inherently introduces significant loss due to the limited Q achievable for the coils on a semiconductor substrate.
  • the amplifiers in a Chireix-type amplifier architecture can, instead, be connected in parallel if an appropriate impedance transformation is incorporated, that is, if the low impedance voltage source outputs (i.e. the individual amplifier outputs) are transformed into high output impedance current sources.
  • the high output impedance current source outputs can be connected in parallel, thereby avoiding the need for a magnetic transformer.
  • this transformation can be achieved with a quarter-wave length transmission line, also referred to as an impedance inverter, as shown in the prior art illustration of FIG. 2 , wherein the characteristic impedance (ZO) of the two quarter-wave length transmission lines is set to match the output impedance of the amplifier stage to the desired load impedance.
  • the impedance inversion can also be achieved using a lumped element equivalent circuit, as known to persons skilled in the art.
  • a lumped element equivalent for broadband may consist of a series inductor, L, and two shunt negative inductances of equal absolute value, ⁇ L, as shown by the prior art illustration of FIG. 3A .
  • the lumped element equivalent circuit shown by the prior art illustration of FIG. 3B could be used for such impedance transformation.
  • the known switched-mode Class F amplifier provides a good approximation to a voltage square-wave across the output terminals of an active device 300 (the active device being a transistor in the usual case connected at its source, through a bias inductor 307 , to a voltage rail 305 ) by “shorting”all even-harmonic voltages and “supporting”all odd-harmonic voltages.
  • the voltage waveform across the output terminals of the active device 300 contains only odd-harmonic components.
  • this sorting of odd- and even-harmonics results in a current passing through the output terminals of the active device 300 that contains the fundamental, and only even-harmonic components.
  • Such “shorting” and “supporting” of the even and odd harmonics, respectively, is conveniently achieved, up to the third harmonic, with a series resonant circuit 310 , 320 tuned to the second harmonic connected across the active device's output terminals, and a parallel resonant circuit 330 and 340 at the third harmonic connected between the output terminal of the active device 300 and the load 350 .
  • the series resonator 310 , 320 effectively shorts the second harmonic of the input signal (Vin) and supports the third harmonic of the input signal, while the parallel resonator 330 , 340 effectively blocks the third harmonic of the input signal from the load 350 .
  • each such harmonic component contains only a voltage component or a current component, the active device 300 does not absorb power other than at the fundamental frequency. Accordingly, as a result of the second and third harmonic resonators, only (approximately) the fundamental frequency signal reaches the load 350 at output terminal 351 .
  • a switched-mode Class F power amplifier configured for parallel connection with at least one other like amplifier for combining signals output from such parallel connected amplifiers.
  • An input component comprises at least one active device configured to be alternately switched by a signal (i.e. an analog phase modulated signal) input thereto to present an amplified signal corresponding to the input signal, the amplified signal constituting a low output impedance voltage source.
  • a lumped element impedance inverter is provided between the input component and an output resonator component, the impedance inverter being configured for transforming the low output impedance voltage source so as to constitute a high output impedance current source configured for the parallel connection. Negative reactive component values required by the impedance inverter are eliminated and effectively provided by incorporating those negative values into pre-selected reactive components of the input and output components.
  • a source-drain parasitic capacitance across the active device is also eliminated by one or more pre-selected reactive components of the input component, with the value(s) of the pre-selected reactive components being predetermined to effectively compensate for the parasitic capacitance.
  • a plurality of the foregoing amplifiers are connected in parallel for combining signals output from the amplifiers wherein an input component is provided for each of the plurality of amplifiers.
  • a common output resonator component is provided (common to all of the plurality of amplifiers) and a lumped element impedance inverter for each of the plurality of amplifiers between the input component and output component.
  • the negative reactive component values required by each impedance inverter is eliminated and effectively provided by incorporating their values into pre-selected reactive components of the input and output components.
  • a method for amplifying an input signal to produce an output signal configured for parallel connection with at least one other like output signal for combining the output signals within a Chireix circuit architecture The input signal is amplified by means of at least one active device configured to be alternately switched by the input signal and an amplified signal corresponding to the input signal is presented, the amplified signal constituting a low output impedance voltage source.
  • a second harmonic resonator configured for shorting a second harmonic signal of said input signal is provided across the active device.
  • the low output impedance voltage source is transformed to constitute a high output impedance current source by means of a lumped element impedance inverter, the high output impedance current source being configured for the parallel connection.
  • a third harmonic resonator blocks a third harmonic signal of the input signal from a load connected to the output signal. Negative reactive component values required by the impedance inverter are eliminated and effectively provided by incorporating those negative values into preselected adjacent reactive components of the resonators.
  • FIG. 1 illustrates a prior art pseudo balanced, transformer (i.e. not having a centre-tap-to-ground connection) for series-combining the output signals (Input 1 and Input 2 ) of a switched-mode power amplifier;
  • FIG. 2 illustrates a quarter-wavelength ( ⁇ /4) transmission line (impedance inverter), useful for transforming a high output impedance to a low output impedance, as known by persons skilled in the art;
  • FIGS. 3A and 3B illustrate two different, alternate lumped element circuit equivalents to the foregoing quarter-wavelength transmission line of FIG. 2 ;
  • FIG. 4 illustrates a conventional Class F switched-mode power amplifier circuit
  • FIG. 5 illustrates a Class F switched-mode power amplifier circuit according to that of FIG. 4 but with the addition of an impedance inverter, per that of FIG. 3A , connected to the output terminal of the amplifier before the load;
  • FIG. 6 illustrates a modified Class F amplifier circuit over that of FIG. 5 , which includes the impedance inverter (transformer) of FIG. 5 but replaces the parallel third-harmonic-tuned resonator circuit of FIG. 5 , with a series third-harmonic-tuned resonator circuit connected across the output terminal of the amplifier to ground;
  • FIG. 7 illustrates a further modified Class F amplifier over that of FIG. 6 , in accordance with the present invention, in parallel connection with a like amplifier according to the invention, wherein the left-most negative inductor ( ⁇ L) of the impedance inverter (transformer) of FIG. 6 is incorporated into the series second-harmonic-tuned resonator circuit of FIG. 6 to produce the modified series second-harmonic-tuned resonator circuit shown in this figure and the rightmost negative inductor ( ⁇ L) of the impedance inverter (transformer) of FIG. 6 is incorporated into the series third-harmonic-tuned resonator circuit of FIG. 6 to produce the modified series third-harmonic-tuned resonator circuit shown in this figure; and,.
  • FIG. 8 illustrates modified parallel-connected circuit of Class F amplifiers configured in accordance with the invention, over that of FIG. 7 , in which the output third harmonic resonator components are replaced by one equivalent output resonator component common to both amplifiers.
  • the inventor has invented a Class F amplifier configured for parallel connection with at least one other like amplifier, for combining the outputs of such parallel connected amplifiers in a Chireix circuit architecture, which overcomes or avoids the disadvantages associated with the foregoing prior art transformer couplings used for combining amplifier outputs and impedance inverters in the form of quarter-wavelength transmission lines or lumped element equivalents thereto having negative reactive components.
  • the present invention is achieved by first transforming, by means of an impedance inverter 335 (consisting of series positive inductor 250 and shunt negative inductors 260 , 270 ), the output of a Class F amplifier (i.e. at terminal 333 ) from that of a low impedance voltage source to a high impedance current source so that such output-transformed amplifier may be connected in parallel with another like amplifier configuration to combine the outputs of the two amplifiers. Then, as illustrated by FIG. 6 , the parallel third harmonic resonator 330 , 340 is transformed through that impedance inverter 335 into a series third harmonic resonator 360 , 370 (i.e.
  • FIG. 7 which shows two such amplifier circuits 500 , 501 , each configured in accordance with the present invention and connected in parallel to present an output signal at terminal 550 representing an amplification and-combination of input signals Vin 1 and Vin 2 ) the negative impedances 260 , 270 are eliminated by incorporating those negative impedance values (effects) into the values of pre-selected existing reactive components adjacent to them.
  • the negative impedance 260 is incorporated into the series second harmonic resonator 310 , 320 to form a modified series second harmonic resonator 310 a, 320 a in the example shown.
  • the source bias voltage 305 is stable, that negative impedance could be incorporated into the source bias inductor 307 .
  • the negative impedance 270 is incorporated into the series third harmonic resonator 360 , 370 in the example shown to form a modified series third harmonic resonator 360 a, 370 a.
  • this modified third harmonic resonator circuit 360 a, 370 a of the amplifier 500 is in parallel connection with the corresponding resonator circuit 360 a, 370 a of the parallel-connected like amplifier 501 , these resonator circuits may be replaced by one equivalent resonator circuit 460 a, 470 a, as shown by FIG. 8 .
  • the inventor has also advantageously eliminated the aforementioned source-drain parasitic capacitance of the Class F amplifier which occurs at high frequencies, by compensating for its presence in the pre-selection of the modified values of the components 310 a, 320 a of the second harmonic resonator.
  • the positive inductance 250 of the impedance inverter can be realized as a wire-bond in a semiconductor product implementation of this circuit, whereby the actual Chireix (parallel) signal combining takes place off die at the package pin.
  • the means and method of performing such a wire-bond realization is described in detail in a co-pending application assigned to the same assignee as this application, entitled “Integrated Circuit Incorporating Wire Bond Inductance” which was filed on 30 Jun., 2003.

Abstract

A switched-mode Class F power amplifier is provided for parallel connection with at least one other like amplifier, within a Chireix architecture, for combining the signals output therefrom. An input component includes at least one active device configured to be alternately switched by a signal input thereto to present an amplified signal corresponding to the input signal and constituting a low output impedance voltage source. A lumped element impedance inverter is provided between the input component and an output resonator component, the impedance inverter being configured for transforming the low output impedance voltage source to instead constitute a high output impedance current source configured for said parallel connection. In accordance with the invention, the negative reactive component values required by the impedance inverter are eliminated and effectively provided by incorporating those values into pre-selected reactive components of the input and output components. Further, a source-drain parasitic capacitance across the active device is eliminated by one or more pre-selected reactive components of the input component, the value(s) of which effectively compensate for the parasitic capacitance.

Description

FIELD OF THE INVENTION
The invention relates to circuitry for radio frequency (i.e. “RF” or “wireless”) transmitters and, in particular, to a switched-mode power amplifier design and configuration for parallel connection with one or more like amplifiers for combining of the signals output therefrom.
BACKGROUND OF THE INVENTION
Typically, power combiners are used in RF transmitters to combine the output signals of parallel power amplifiers into one high power RF output signal for wireless transmission. In these known transmitter structures the signals are first amplified by the power amplifiers and then they are combined by a separate power combiner to produce a combined amplified signal for transmission. Depending upon the circuit architecture and signal format used, however, it becomes necessary to make trade-offs between reducing power losses and achieving isolation between input signals of the combiner.
The need for efficiency is a particularly important design factor for the highly integrated requirements of transceivers used for wireless local area networks (LANs) and employing modulation formats such as OFDM (Orthogonal Frequency Division Multiplex). Moreover, the assignee of this invention and application has developed signal modulation methods, using OFDM signal format, whereby information signals are deconstructed into independent component signals, these independent signals being more efficiently processed and modulated than the original information signals from which they derive, and then the independent signals are up-converted, amplified and combined prior to transmission. Use of such independent modulated signals presents additional challenges to achieving efficiency at the amplification/combination stages of the transmitter, however, because the conventional model of amplification followed by combining, using known power amplifiers and combiners, is subject to inherent loss and isolation limitations.
The Chireix-type power amplifier, known to persons skilled in the art, represents one of the LINC (Linear amplification with Nonlinear Components) architectures and uses linear, saturated, or switch-mode amplifiers to provide amplification for signals having amplitude as well as phase modulation. It operates by adjusting the phase applied to two amplifiers, and combining the outputs through a combiner to reintroduce the amplitude modulation. An appropriate combiner for the Chireix architecture not only reinserts the amplitude modulation to the signal, it also provides a dynamic adjustment of the load impedance presented to each amplifier (out-phasing). This out-phasing adjustment of the load impedances is such that the DC current through each active device decreases as the combined output amplitude decreases, thereby maintaining high efficiency.
Appropriate combiners for a Chireix-type amplifier do not provide any isolation between the outputs of the two amplifiers. One example of this is a “pseudo” balanced magnetic transformer (i.e. having no center tap to ground connection) connecting the individual amplifier outputs to the two terminals, Input 1 and Input 2, of the input winding 100, as shown in the prior art illustration of FIG. 1. Here the magnetic transformer effectively combines, in series, in the output winding 200, the signals from the individual amplifiers and, for efficiency, the outputs of the individual amplifiers must be low impedance voltage sources. However, it will be understood by the skilled reader that such use of a magnetic transformer inherently introduces significant loss due to the limited Q achievable for the coils on a semiconductor substrate.
Alternatively, the amplifiers in a Chireix-type amplifier architecture can, instead, be connected in parallel if an appropriate impedance transformation is incorporated, that is, if the low impedance voltage source outputs (i.e. the individual amplifier outputs) are transformed into high output impedance current sources. With such a transformation, the high output impedance current source outputs can be connected in parallel, thereby avoiding the need for a magnetic transformer. As known by persons skilled in the art, this transformation can be achieved with a quarter-wave length transmission line, also referred to as an impedance inverter, as shown in the prior art illustration of FIG. 2, wherein the characteristic impedance (ZO) of the two quarter-wave length transmission lines is set to match the output impedance of the amplifier stage to the desired load impedance.
Instead of using such a quarter-wave length transmission line, the impedance inversion (transformation) can also be achieved using a lumped element equivalent circuit, as known to persons skilled in the art. Such a lumped element equivalent for broadband may consist of a series inductor, L, and two shunt negative inductances of equal absolute value, −L, as shown by the prior art illustration of FIG. 3A. Here, a load impedance ZL is transformed into an input impedance Zin 2L2/ZL. Alternatively, the lumped element equivalent circuit shown by the prior art illustration of FIG. 3B could be used for such impedance transformation. As will be appreciated by the skilled reader, these negative inductances, −L, can be realized, for a limited bandwidth (spot frequency) application, with the use of shunt capacitances; however, this is not applicable for a practical Class F amplifier for which such impedance inversion is needed at each of the first, second and third harmonics. Consequently, the realization of such a transformation for Class F amplifier circuits presents an obstacle for the practical design and implementation of such a circuit.
As illustrated by FIG. 4, the known switched-mode Class F amplifier provides a good approximation to a voltage square-wave across the output terminals of an active device 300 (the active device being a transistor in the usual case connected at its source, through a bias inductor 307, to a voltage rail 305) by “shorting”all even-harmonic voltages and “supporting”all odd-harmonic voltages. As a result, the voltage waveform across the output terminals of the active device 300 contains only odd-harmonic components. In addition, this sorting of odd- and even-harmonics results in a current passing through the output terminals of the active device 300 that contains the fundamental, and only even-harmonic components. Such “shorting” and “supporting” of the even and odd harmonics, respectively, is conveniently achieved, up to the third harmonic, with a series resonant circuit 310, 320 tuned to the second harmonic connected across the active device's output terminals, and a parallel resonant circuit 330 and 340 at the third harmonic connected between the output terminal of the active device 300 and the load 350. In operation, the series resonator 310, 320 effectively shorts the second harmonic of the input signal (Vin) and supports the third harmonic of the input signal, while the parallel resonator 330, 340 effectively blocks the third harmonic of the input signal from the load 350. Since each such harmonic component contains only a voltage component or a current component, the active device 300 does not absorb power other than at the fundamental frequency. Accordingly, as a result of the second and third harmonic resonators, only (approximately) the fundamental frequency signal reaches the load 350 at output terminal 351.
From a practical perspective, it is known that using such resonator circuits to process the input signal only up to its third harmonic components can provide a power-added efficiency of up to about 90%. However, it is also known that this Class F amplifier circuit architecture, where used at high frequencies, presents a design problem relating to the resonator circuits in that a source-drain (emitter-collector) parasitic capacitance results across the active device and causes the resonance values of these resonators to detune. In turn, this means that some level of amplitude for all harmonics of the voltage and current will exist, in practice, at such high frequencies.
By reason of the foregoing limitations, for a Class F, Chiriex-type amplifier architecture there exists a need for new and efficient means to achieve power amplification and combining of modulated signals in transmitters.
SUMMARY OF THE INVENTION
In accordance with the invention, there is provided a switched-mode Class F power amplifier configured for parallel connection with at least one other like amplifier for combining signals output from such parallel connected amplifiers. An input component comprises at least one active device configured to be alternately switched by a signal (i.e. an analog phase modulated signal) input thereto to present an amplified signal corresponding to the input signal, the amplified signal constituting a low output impedance voltage source. A lumped element impedance inverter is provided between the input component and an output resonator component, the impedance inverter being configured for transforming the low output impedance voltage source so as to constitute a high output impedance current source configured for the parallel connection. Negative reactive component values required by the impedance inverter are eliminated and effectively provided by incorporating those negative values into pre-selected reactive components of the input and output components.
Optionally, a source-drain parasitic capacitance across the active device is also eliminated by one or more pre-selected reactive components of the input component, with the value(s) of the pre-selected reactive components being predetermined to effectively compensate for the parasitic capacitance.
In accordance with another aspect of the invention a plurality of the foregoing amplifiers are connected in parallel for combining signals output from the amplifiers wherein an input component is provided for each of the plurality of amplifiers. A common output resonator component is provided (common to all of the plurality of amplifiers) and a lumped element impedance inverter for each of the plurality of amplifiers between the input component and output component. As for the single amplifier, the negative reactive component values required by each impedance inverter is eliminated and effectively provided by incorporating their values into pre-selected reactive components of the input and output components.
In accordance with a further aspect of the invention there is provided a method for amplifying an input signal to produce an output signal configured for parallel connection with at least one other like output signal for combining the output signals within a Chireix circuit architecture. The input signal is amplified by means of at least one active device configured to be alternately switched by the input signal and an amplified signal corresponding to the input signal is presented, the amplified signal constituting a low output impedance voltage source. A second harmonic resonator configured for shorting a second harmonic signal of said input signal is provided across the active device. The low output impedance voltage source is transformed to constitute a high output impedance current source by means of a lumped element impedance inverter, the high output impedance current source being configured for the parallel connection. A third harmonic resonator blocks a third harmonic signal of the input signal from a load connected to the output signal. Negative reactive component values required by the impedance inverter are eliminated and effectively provided by incorporating those negative values into preselected adjacent reactive components of the resonators.
BRIEF DESCRIPTION OF THE DRAWINGS
An exemplary preferred embodiment of the invention is described in detail below with reference to the following drawings in which like references refer to like elements throughout:
FIG. 1 illustrates a prior art pseudo balanced, transformer (i.e. not having a centre-tap-to-ground connection) for series-combining the output signals (Input 1 and Input 2) of a switched-mode power amplifier;
FIG. 2 illustrates a quarter-wavelength (λ/4) transmission line (impedance inverter), useful for transforming a high output impedance to a low output impedance, as known by persons skilled in the art;
FIGS. 3A and 3B illustrate two different, alternate lumped element circuit equivalents to the foregoing quarter-wavelength transmission line of FIG. 2;
FIG. 4 illustrates a conventional Class F switched-mode power amplifier circuit;
FIG. 5 illustrates a Class F switched-mode power amplifier circuit according to that of FIG. 4 but with the addition of an impedance inverter, per that of FIG. 3A, connected to the output terminal of the amplifier before the load;
FIG. 6 illustrates a modified Class F amplifier circuit over that of FIG. 5, which includes the impedance inverter (transformer) of FIG. 5 but replaces the parallel third-harmonic-tuned resonator circuit of FIG. 5, with a series third-harmonic-tuned resonator circuit connected across the output terminal of the amplifier to ground;
FIG. 7 illustrates a further modified Class F amplifier over that of FIG. 6, in accordance with the present invention, in parallel connection with a like amplifier according to the invention, wherein the left-most negative inductor (−L) of the impedance inverter (transformer) of FIG. 6 is incorporated into the series second-harmonic-tuned resonator circuit of FIG. 6 to produce the modified series second-harmonic-tuned resonator circuit shown in this figure and the rightmost negative inductor (−L) of the impedance inverter (transformer) of FIG. 6 is incorporated into the series third-harmonic-tuned resonator circuit of FIG. 6 to produce the modified series third-harmonic-tuned resonator circuit shown in this figure; and,.
FIG. 8 illustrates modified parallel-connected circuit of Class F amplifiers configured in accordance with the invention, over that of FIG. 7, in which the output third harmonic resonator components are replaced by one equivalent output resonator component common to both amplifiers.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Surprisingly, the inventor has invented a Class F amplifier configured for parallel connection with at least one other like amplifier, for combining the outputs of such parallel connected amplifiers in a Chireix circuit architecture, which overcomes or avoids the disadvantages associated with the foregoing prior art transformer couplings used for combining amplifier outputs and impedance inverters in the form of quarter-wavelength transmission lines or lumped element equivalents thereto having negative reactive components.
As illustrated by FIG. 5, the present invention is achieved by first transforming, by means of an impedance inverter 335 (consisting of series positive inductor 250 and shunt negative inductors 260, 270), the output of a Class F amplifier (i.e. at terminal 333) from that of a low impedance voltage source to a high impedance current source so that such output-transformed amplifier may be connected in parallel with another like amplifier configuration to combine the outputs of the two amplifiers. Then, as illustrated by FIG. 6, the parallel third harmonic resonator 330, 340 is transformed through that impedance inverter 335 into a series third harmonic resonator 360, 370 (i.e. the parallel resonator 330, 340 is replaced by a series resonator 360, 370 across the output terminal 351 and ground). Then, as illustrated by FIG. 7 (which shows two such amplifier circuits 500, 501, each configured in accordance with the present invention and connected in parallel to present an output signal at terminal 550 representing an amplification and-combination of input signals Vin1 and Vin2) the negative impedances 260, 270 are eliminated by incorporating those negative impedance values (effects) into the values of pre-selected existing reactive components adjacent to them.
Specifically, as shown by FIG. 7, the negative impedance 260 is incorporated into the series second harmonic resonator 310, 320 to form a modified series second harmonic resonator 310a, 320a in the example shown. Alternatively, if the source bias voltage 305 is stable, that negative impedance could be incorporated into the source bias inductor 307. Also as illustrated by FIG. 7, the negative impedance 270 is incorporated into the series third harmonic resonator 360, 370 in the example shown to form a modified series third harmonic resonator 360a, 370a.
Further, since this modified third harmonic resonator circuit 360a, 370a of the amplifier 500 is in parallel connection with the corresponding resonator circuit 360a, 370a of the parallel-connected like amplifier 501, these resonator circuits may be replaced by one equivalent resonator circuit 460a, 470a, as shown by FIG. 8.
Moreover, the inventor has also advantageously eliminated the aforementioned source-drain parasitic capacitance of the Class F amplifier which occurs at high frequencies, by compensating for its presence in the pre-selection of the modified values of the components 310a, 320a of the second harmonic resonator.
It has also been determined by the assignee of this invention that the positive inductance 250 of the impedance inverter can be realized as a wire-bond in a semiconductor product implementation of this circuit, whereby the actual Chireix (parallel) signal combining takes place off die at the package pin. The means and method of performing such a wire-bond realization is described in detail in a co-pending application assigned to the same assignee as this application, entitled “Integrated Circuit Incorporating Wire Bond Inductance” which was filed on 30 Jun., 2003.
The individual electronic and processing functions utilised in the foregoing described embodiment are, individually, well understood by those skilled in the art. Appropriate values to be pre-selected for the surrounding reactive components, for given signal frequencies, to incorporate the negative reactive values of the impedance inverter in accordance with the invention, can be readily determined, as needed, by such skilled persons. It is to be understood by the skilled reader that a variety of other implementations of the invention, apart from the specific embodiment illustrated herein, may be devised for substitution. The claimed invention herein is intended to encompass all such alternative implementations, substitutions and equivalents. Persons skilled in the field of electronic and communication design will be readily able to apply the present invention to an appropriate implementation for a given application.
Consequently, it is to be understood that the particular embodiments shown and described herein by way of illustration are not intended to limit the scope of the invention claimed by the inventors/assignee which is defined by the appended claims.

Claims (22)

1. A switched-mode Class F power amplifier configured for parallel connection with at least one other said amplifier for combining signals output from such parallel connected amplifiers, said amplifier comprising:
(a) an input component comprising at least one active device configured to be alternately switched by a signal input thereto to present an amplified signal corresponding to said input signal, said amplified signal constituting a low output impedance voltage source;
(b) an output resonator component; and,
(c) a lumped element impedance inverter connected between said input component and said output component, said impedance inverter configured for transforming said low output impedance voltage source so as to constitute a high output impedance current source, and said high output impedance current source configured for said parallel connection;
wherein negative reactive component values theoretically required by said impedance inverter are actually incorporated into pre-selected reactive components of said input and output components.
2. A switched-mode power amplifier according to claim 1 wherein said input signal is an analog phase modulated signal.
3. A method for producing a switched-mode power amplifier, said method comprising:
(a) designing a theoretical lumped-element impedance inverter configured to transform a low output impedance voltage source into a high output impedance current source, such ideal impedance inverter incorporating theoretically negative reactive component values;
(b) adding an input component comprising at least one active device configured to be alternately switched by an input signal thereto to present an amplified signal corresponding to said input signal, said amplified signal constituting a low output impedance voltage source;
(c) adding an output resonator component; and
(d) adjusting values of one or more elements coupled to the input and output components such that the theoretically negative reactive components may be eliminated, and eliminating the theoretically negative reactive components from the design.
4. A method according to claim 3 whereby said input signal is an analog phase modulated signal.
5. A plurality of switched-mode Class F power amplifiers in parallel connection for combining signals output from said amplifiers, said parallel-connected amplifiers comprising:
(a) an input component for each of said plurality of amplifiers, each said input component comprising at least one active device configured to be alternately switched by a signal input thereto to present an amplified signal corresponding to said input signal, said amplified signal constituting a low output impedance voltage source;
(b) a common output resonator component for said plurality of amplifiers; and,
(c) a lumped element impedance inverter for each of said plurality of amplifiers between said input component and said output component, said impedance inverter configured for transforming said low output impedance voltage source so as to constitute a high output impedance current source and said high output impedance current source configured for said parallel connection;
wherein negative reactive component values required by said impedance inverter are eliminated and effectively provided by incorporating said values into pre-selected reactive components of said input and output components.
6. The switched-mode power amplifier according to claim 1, wherein the input component comprises a first inductor and a first capacitor, connected in series and electrically connected to the input of the impedance inverter.
7. The switched-mode power amplifier according to claim 6, wherein the output component comprises a second inductor and a second capacitor, connected in series and electrically connected to the output of the impedance inverter.
8. The switched-mode power amplifier according to claim 7, wherein the values for each of the first inductor, first capacitor, second inductor and second capacitor are selected in order to compensate for the negative reactive component values theoretically required but not otherwise included in the amplifier.
9. The method of claim 3, further comprising manufacturing the switched-mode power amplifier.
10. The method of claim 9, wherein the input component comprises a first inductor and a first capacitor, connected in series and electrically connected to the input of the impedance inverter.
11. The method of claim 10, wherein the output component comprises a second inductor and a second capacitor, connected in series and electrically connected to the output of the impedance inverter.
12. The method of claim 11, further comprising the step of selecting the values for each of the first inductor, first capacitor, second inductor and second capacitor in order to compensate for the negative reactive component values theoretically required but not present in the manufactured amplifier.
13. An apparatus, comprising:
means for amplifying an input signal to generate a low output impedance voltage source by alternately switching an input component, wherein the input component includes at least one active device responsive to the input signal; and
means for transforming the low output impedance voltage source into a high output impedance current source using a lumped-element impedance inverter coupled to the means for amplifying;
wherein negative reactive component values theoretically required by the lumped-element impedance inverter include pre-selected reactive components; and
wherein the means for amplifying includes a first inductor means serially connected to a first capacitor means and electrically connected to an input of the lumped-element impedance inverter.
14. The apparatus of claim 13, further comprising:
output resonator means coupled to both the means for amplifying and the means for transforming;
wherein the output resonator means includes a second inductor means serially connected to a second capacitor means and electrically connected to an output of the lumped-element impedance inverter.
15. The apparatus of claim 14, further comprising means for selecting the values for each of the first inductor means, the first capacitor means, the second inductor means, and the second capacitor means to compensate for the negative reactive component values theoretically required but not present in the apparatus.
16. An apparatus, comprising:
means for amplifying an input signal;
means for resonating a resonant frequency, wherein the means for resonating is coupled to the means for amplifying; and
means for inverting an impedance, wherein the means for inverting is coupled between the means for amplifying and the means for resonating;
wherein the means for inverting includes means for transforming an output of the means for amplifying from a voltage source having a low output impedance into a current source having a high output impedance; and
wherein the means for inverting further includes one or more negative valued theoretical reactive components realized as one or more positive valued reactive components of at least one of the means for amplifying or the means for resonating, or a combination thereof.
17. The apparatus of claim 16, wherein the means for resonating comprises means for realizing an inductance serially connected to a means for realizing a capacitance, and wherein at least one of the means for realizing an inductance or the means for realizing a capacitance, or a combination thereof, incorporates a negative reactive component of the means for inverting.
18. An amplifier, comprising:
an input component including at least one active device configured to be alternately switched by an input signal to generate a low output impedance voltage source; and
an impedance converter coupled between the input component and an output component and configured to generate a high output impedance current source in response to the low output impedance voltage source;
wherein the input component and the output component both include reactive components that eliminate negative reactive component values theoretically required by the impedance converter.
19. The amplifier of claim 18, wherein the input signal comprises an analog phase-modulated signal.
20. The amplifier of claim 18, wherein the input component comprises a first inductor serially connected to a first capacitor.
21. The amplifier of claim 20, wherein the output component comprises a second inductor serially connected to a second capacitor.
22. The amplifier of claim 21, wherein the first inductor, the first capacitor, the second inductor, and the second capacitor are selected to compensate for the negative reactive component values theoretically required but not present in the amplifier.
US11/787,231 2003-07-08 2007-04-12 Switched-mode power amplifier using lumped element impedance inverter for parallel combining Expired - Lifetime USRE42612E1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US11/787,231 USRE42612E1 (en) 2003-07-08 2007-04-12 Switched-mode power amplifier using lumped element impedance inverter for parallel combining

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/615,468 US6879209B2 (en) 2003-07-08 2003-07-08 Switched-mode power amplifier using lumped element impedance inverter for parallel combining
US11/787,231 USRE42612E1 (en) 2003-07-08 2007-04-12 Switched-mode power amplifier using lumped element impedance inverter for parallel combining

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US10/615,468 Reissue US6879209B2 (en) 2003-07-08 2003-07-08 Switched-mode power amplifier using lumped element impedance inverter for parallel combining

Publications (1)

Publication Number Publication Date
USRE42612E1 true USRE42612E1 (en) 2011-08-16

Family

ID=33564564

Family Applications (4)

Application Number Title Priority Date Filing Date
US10/615,468 Expired - Lifetime US6879209B2 (en) 2003-07-08 2003-07-08 Switched-mode power amplifier using lumped element impedance inverter for parallel combining
US11/099,916 Expired - Lifetime US7151407B2 (en) 2003-07-08 2005-04-06 Switched-mode power amplifier using lumped element impedance inverter for parallel combining
US11/612,323 Abandoned US20070205828A1 (en) 2003-07-08 2006-12-18 Switched mode power amplifier using lumped element impedance inverter for parallel combining
US11/787,231 Expired - Lifetime USRE42612E1 (en) 2003-07-08 2007-04-12 Switched-mode power amplifier using lumped element impedance inverter for parallel combining

Family Applications Before (3)

Application Number Title Priority Date Filing Date
US10/615,468 Expired - Lifetime US6879209B2 (en) 2003-07-08 2003-07-08 Switched-mode power amplifier using lumped element impedance inverter for parallel combining
US11/099,916 Expired - Lifetime US7151407B2 (en) 2003-07-08 2005-04-06 Switched-mode power amplifier using lumped element impedance inverter for parallel combining
US11/612,323 Abandoned US20070205828A1 (en) 2003-07-08 2006-12-18 Switched mode power amplifier using lumped element impedance inverter for parallel combining

Country Status (1)

Country Link
US (4) US6879209B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130222058A1 (en) * 2012-02-29 2013-08-29 Fujitsu Limited Amplifier

Families Citing this family (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7660562B2 (en) * 2004-06-21 2010-02-09 M/A-Com Technology Solutions Holdings, Inc. Combined matching and filter circuit
US7355470B2 (en) * 2006-04-24 2008-04-08 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including embodiments for amplifier class transitioning
US7327803B2 (en) 2004-10-22 2008-02-05 Parkervision, Inc. Systems and methods for vector power amplification
US7265619B2 (en) * 2005-07-06 2007-09-04 Raytheon Company Two stage microwave Class E power amplifier
US7911272B2 (en) 2007-06-19 2011-03-22 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including blended control embodiments
US8013675B2 (en) 2007-06-19 2011-09-06 Parkervision, Inc. Combiner-less multiple input single output (MISO) amplification with blended control
US9106316B2 (en) * 2005-10-24 2015-08-11 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification
WO2007069193A2 (en) * 2005-12-15 2007-06-21 Nxp B.V. Polar modulation system
US7937106B2 (en) * 2006-04-24 2011-05-03 ParkerVision, Inc, Systems and methods of RF power transmission, modulation, and amplification, including architectural embodiments of same
US8031804B2 (en) * 2006-04-24 2011-10-04 Parkervision, Inc. Systems and methods of RF tower transmission, modulation, and amplification, including embodiments for compensating for waveform distortion
EP2039001B1 (en) * 2006-07-12 2014-04-02 Qualcomm Technologies, Inc. Load-line adaptation
US8315336B2 (en) 2007-05-18 2012-11-20 Parkervision, Inc. Systems and methods of RF power transmission, modulation, and amplification, including a switching stage embodiment
US7881401B2 (en) * 2006-11-17 2011-02-01 Infineon Technologies Ag Transmitter arrangement and signal processing method
US7795672B2 (en) * 2006-12-26 2010-09-14 Sensor Electronic Technology, Inc. Profiled gate field effect transistor with enhanced high harmonic gain
US7560985B2 (en) * 2006-12-26 2009-07-14 Sensor Electronic Technology, Inc. Two-stage amplification using intermediate non-linear square wave
US7620129B2 (en) * 2007-01-16 2009-11-17 Parkervision, Inc. RF power transmission, modulation, and amplification, including embodiments for generating vector modulation control signals
WO2009005768A1 (en) * 2007-06-28 2009-01-08 Parkervision, Inc. Systems and methods of rf power transmission, modulation, and amplification
JP2010087934A (en) * 2008-09-30 2010-04-15 Panasonic Corp Matching circuit, high-frequency power amplifier and cellular phone
US8174322B2 (en) * 2010-05-04 2012-05-08 Nxp B.V. Power control of reconfigurable outphasing chireix amplifiers and methods
US8203386B2 (en) * 2010-05-04 2012-06-19 Nxp B.V. Reconfigurable outphasing Chireix amplifiers and methods
KR20140026458A (en) 2011-04-08 2014-03-05 파커비전, 인크. Systems and methods of rf power transmission, modulation, and amplification
JP6174574B2 (en) 2011-06-02 2017-08-02 パーカーヴィジョン インコーポレイテッド Antenna control
WO2013066466A2 (en) * 2011-08-12 2013-05-10 Bae Systems Integration And Electronic Systems Integration Inc. Low voltage high efficiency gallium arsenide power amplifier
US9024691B2 (en) * 2013-05-17 2015-05-05 Georgia Tech Research Corporation Adaptive power amplifier and methods of making same
US9419568B2 (en) * 2013-06-03 2016-08-16 Skyworks Solutions, Inc. Circuits and methods related to power amplifier efficiency based on multi-harmonic approximation
WO2015042142A1 (en) 2013-09-17 2015-03-26 Parkervision, Inc. Method, apparatus and system for rendering an information bearing function of time
DE102015212220A1 (en) 2015-06-30 2017-01-05 TRUMPF Hüttinger GmbH + Co. KG RF amplifier arrangement
KR101901510B1 (en) * 2017-02-24 2018-09-28 전자부품연구원 Power Amplifier Using Equivalent Transformer
US10103697B1 (en) * 2017-10-23 2018-10-16 Nxp Usa, Inc. Multiphase pulse modulated transmitter
US10784821B2 (en) * 2018-12-19 2020-09-22 Nxp Usa, Inc. High power radio frequency amplifiers and methods of manufacture thereof
US10784822B2 (en) * 2018-12-19 2020-09-22 Nxp Usa, Inc. High power radio frequency amplifiers and methods of manufacture thereof
US20230238881A1 (en) * 2022-01-27 2023-07-27 Qualcomm Incorporated Radio frequency (rf) power amplifier with transformer for improved output power, wideband, and spurious rejection

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6011345A (en) * 1996-02-08 2000-01-04 Emf Industries, Inc. Device and method for controlling transductive systems
US6285251B1 (en) 1998-04-02 2001-09-04 Ericsson Inc. Amplification systems and methods using fixed and modulated power supply voltages and buck-boost control
US6630899B2 (en) 2000-07-20 2003-10-07 Tripath Technology, Inc. Scheme for maximizing efficiency of power amplifier under power backoff conditions
US20040027199A1 (en) 2001-12-03 2004-02-12 Icefyre Semiconductor Corporation Switched-mode power amplifier integrally performing power combining
US6724255B2 (en) 2000-10-10 2004-04-20 California Institute Of Technology Class E/F switching power amplifiers

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6011345A (en) * 1996-02-08 2000-01-04 Emf Industries, Inc. Device and method for controlling transductive systems
US6285251B1 (en) 1998-04-02 2001-09-04 Ericsson Inc. Amplification systems and methods using fixed and modulated power supply voltages and buck-boost control
US6630899B2 (en) 2000-07-20 2003-10-07 Tripath Technology, Inc. Scheme for maximizing efficiency of power amplifier under power backoff conditions
US6724255B2 (en) 2000-10-10 2004-04-20 California Institute Of Technology Class E/F switching power amplifiers
US20040027199A1 (en) 2001-12-03 2004-02-12 Icefyre Semiconductor Corporation Switched-mode power amplifier integrally performing power combining

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130222058A1 (en) * 2012-02-29 2013-08-29 Fujitsu Limited Amplifier
CN103296980A (en) * 2012-02-29 2013-09-11 富士通株式会社 Amplifier
US8836432B2 (en) * 2012-02-29 2014-09-16 Fujitsu Limited Amplifier
CN103296980B (en) * 2012-02-29 2016-05-11 富士通株式会社 Amplifier

Also Published As

Publication number Publication date
US7151407B2 (en) 2006-12-19
US20050007194A1 (en) 2005-01-13
US20050195031A1 (en) 2005-09-08
US6879209B2 (en) 2005-04-12
US20070205828A1 (en) 2007-09-06

Similar Documents

Publication Publication Date Title
USRE42612E1 (en) Switched-mode power amplifier using lumped element impedance inverter for parallel combining
US6937096B2 (en) Switched-mode power amplifier integrally performing power combining
USRE42447E1 (en) Chireix architecture using low impedance amplifiers
US6577199B2 (en) Harmonic matching network for a saturated amplifier
US10218315B2 (en) Doherty amplifier
JP5711354B2 (en) Class characteristic variable amplifier
JP4476534B2 (en) Amplifier circuit
US9806673B2 (en) Class-E outphasing power amplifier with efficiency and output power enhancement circuits and method
EP2262107B1 (en) Inverse class F amplifier and method
US10432147B2 (en) Inverted three-stage Doherty amplifier
JPH0732335B2 (en) High frequency amplifier
EP2838195B1 (en) Combiner circuit for a class-e outphasing power amplifier
JPH11251849A (en) High frequency power amplifier
Lee et al. A CMOS outphasing power amplifier with integrated single-ended Chireix combiner
US6900696B2 (en) Shared-current electronic systems
US9319255B2 (en) Transmitter, signal-synthesizing circuit, and signal-synthesizing method
WO2016056952A1 (en) Amplifier circuit and method
US20120126886A1 (en) Method and arrangement in a mobile communication system
KR102119359B1 (en) Outphasing power amplifier based on power-combining transformer including structure for improving efficiency
KR102165176B1 (en) Doherty power amplifier and the method of modulating load impedance of the amplifier
CN115088191A (en) Power amplifying circuit, high frequency circuit and communication device
US11271527B2 (en) Broadband harmonic load modulation doherty amplifiers
US7636017B2 (en) High-frequency power amplifier
WO2021250721A1 (en) Amplification circuit
US9385663B2 (en) Envelope tracking push-pull or differential power amplifier

Legal Events

Date Code Title Description
AS Assignment

Owner name: ZARBANA DIGITAL FUND LLC, DELAWARE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ICEFYRE SEMICONDUCTOR, INC.;REEL/FRAME:019561/0758

Effective date: 20051223

AS Assignment

Owner name: ICEFYRE SEMICONDUCTOR, INC., CANADA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ICEFYRE SEMICONDUCTOR CORPORATION;REEL/FRAME:026096/0805

Effective date: 20051031

Owner name: ICEFYRE SEMICONDUCTOR CORPORATION, CANADA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:GRUNDLINGH, JOHAN M.;REEL/FRAME:026096/0558

Effective date: 20030704

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12