Noise conversion gain limited RF power amplifier

Information

  • Patent Grant
  • 9203353
  • Patent Number
    9,203,353
  • Date Filed
    Friday, March 14, 2014
    10 years ago
  • Date Issued
    Tuesday, December 1, 2015
    9 years ago
Abstract
A radio frequency (RF) power amplifier (PA) and an envelope tracking power supply are disclosed. The RF PA receives and amplifies an RF input signal to provide an RF transmit signal using an envelope power supply voltage. The envelope tracking power supply provides the envelope power supply voltage based on a setpoint, which has been constrained so as to limit a noise conversion gain (NCG) of the RF PA to not exceed a target NCG.
Description
FIELD OF THE DISCLOSURE

Embodiments of the present disclosure relate to envelope tracking power supplies and radio frequency (RF) power amplifiers, either of which may be used in RF communication systems.


BACKGROUND

As wireless communications technologies evolve, wireless communications systems become increasingly sophisticated. As such, wireless communications protocols continue to expand and change to take advantage of the technological evolution. As a result, to maximize flexibility, many wireless communications devices must be capable of supporting any number of wireless communications protocols, each of which may have certain performance requirements, such as specific out-of-band emissions requirements, linearity requirements, noise limitations, or the like. Further, portable wireless communications devices are typically battery powered and need to be relatively small, and have low cost. As such, to minimize size, cost, and power consumption, RF circuitry in such a device needs to be as simple, small, and efficient as is practical. Thus, there is a need for RF circuitry in a communications device that is low cost, small, simple, and efficient.


SUMMARY

A radio frequency (RF) power amplifier (PA) and an envelope tracking power supply are disclosed according to one embodiment of the present disclosure. The RF PA receives and amplifies an RF input signal to provide an RF transmit signal using an envelope power supply voltage. The envelope tracking power supply provides the envelope power supply voltage based on a setpoint, which has been constrained so as to limit a noise conversion gain (NCG) of the RF PA to not exceed a target NCG.


Those skilled in the art will appreciate the scope of the disclosure and realize additional aspects thereof after reading the following detailed description in association with the accompanying drawings.





BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.



FIG. 1 shows an RF communications system according to one embodiment of the RF communications system.



FIG. 2 is a graph illustrating an RF transmit signal and an envelope power supply voltage shown in FIG. 1 according to one embodiment of the RF transmit signal and the envelope power supply voltage.



FIG. 3 shows the RF communications system according to an alternate embodiment of the RF communications system.



FIG. 4 shows details of an envelope tracking power supply illustrated in FIG. 1 according to one embodiment of the envelope tracking power supply.



FIG. 5 shows the RF communications system according to another embodiment of the RF communications system.



FIG. 6 shows the RF communications system according to a further embodiment of the RF communications system.



FIG. 7 shows an RF PA calibration environment according to one embodiment of the RF PA calibration environment.



FIG. 8 is a graph illustrating an RF transmit band associated with an RF transmit signal and an RF receive band associated with an RF receive signal illustrated in FIG. 1 according to one embodiment of the RF communications system.



FIG. 9 is a graph illustrating a relationship between the envelope power supply voltage and an input power to an RF PA illustrated in FIG. 1 according to one embodiment of the RF communications system.



FIG. 10 is a graph illustrating a relationship between the envelope power supply voltage and the input power to the RF PA illustrated in FIG. 1 according to an alternate embodiment of the RF communications system.



FIG. 11 is a graph illustrating a relationship between the envelope power supply voltage and the input power to the RF PA illustrated in FIG. 1 according to an additional embodiment of the RF communications system.



FIG. 12 is a graph illustrating a relationship between the envelope power supply voltage and the input power to the RF PA illustrated in FIG. 1 according to another embodiment of the RF communications system.





DETAILED DESCRIPTION

The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the disclosure and illustrate the best mode of practicing the disclosure. Upon reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.


An RF PA and an envelope tracking power supply are disclosed according to one embodiment of the present disclosure. The RF PA receives and amplifies an RF input signal to provide an RF transmit signal using an envelope power supply voltage. The envelope tracking power supply provides the envelope power supply voltage based on a setpoint, which has been constrained so as to limit a noise conversion gain (NCG) of the RF PA to not exceed a target NCG.



FIG. 1 shows an RF communications system 10 according to one embodiment of the RF communications system 10. The RF communications system 10 includes RF transmitter circuitry 12, RF system control circuitry 14, RF front-end circuitry 16, an RF antenna 18, and a DC power source 20. The RF transmitter circuitry 12 includes transmitter control circuitry 22, an RF PA 24, an envelope tracking power supply 26, and PA bias circuitry 28. The RF system control circuitry 14 includes envelope control circuitry 29 and an RF modulator 30.


In one embodiment of the RF communications system 10, the RF front-end circuitry 16 receives via the RF antenna 18, processes, and forwards an RF receive signal RFR to the RF system control circuitry 14. In general, the RF system control circuitry 14 provides an envelope power supply control signal VRMP and a transmitter configuration signal PACS to the transmitter control circuitry 22. Further, the RF system control circuitry 14 provides an RF input signal RFI to the RF PA 24. Specifically, the envelope control circuitry 29 provides the envelope power supply control signal VRMP and the RF modulator 30 provides the RF input signal RFI. The DC power source 20 provides a DC source signal VDC to the envelope tracking power supply 26. The DC source signal VDC has a DC source voltage DCV. In one embodiment of the DC power source 20, the DC power source 20 is a battery.


The transmitter control circuitry 22 is coupled to the envelope tracking power supply 26 and to the PA bias circuitry 28. The envelope tracking power supply 26 provides an envelope power supply signal EPS to the RF PA 24 based on the envelope power supply control signal VRMP. The envelope power supply signal EPS has an envelope power supply voltage EPV. The DC source signal VDC provides power to the envelope tracking power supply 26. As such, the envelope power supply signal EPS is based on the DC source signal VDC. The envelope power supply control signal VRMP is representative of a setpoint of the envelope power supply voltage EPV. The setpoint of the envelope power supply voltage EPV is a desired magnitude of the envelope power supply voltage EPV that the envelope tracking power supply 26 endeavors to reach.


In this regard, the envelope tracking power supply 26 provides the envelope power supply voltage EPV based on the setpoint of the envelope power supply voltage EPV. The RF PA 24 receives and amplifies the RF input signal RFI to provide an RF transmit signal RFT using the envelope power supply voltage EPV. The envelope power supply voltage EPV provides power for amplification. The RF front-end circuitry 16 receives, processes, and transmits the RF transmit signal RFT via the RF antenna 18. In one embodiment of the RF transmitter circuitry 12, the transmitter control circuitry 22 configures the RF transmitter circuitry 12 based on the transmitter configuration signal PACS.


The PA bias circuitry 28 provides a PA bias signal PAB to the RF PA 24. In this regard, the PA bias circuitry 28 biases the RF PA 24 via the PA bias signal PAB. In one embodiment of the PA bias circuitry 28, the PA bias circuitry 28 biases the RF PA 24 based on the transmitter configuration signal PACS. In one embodiment of the RF front-end circuitry 16, the RF front-end circuitry 16 includes at least one RF switch, at least one RF amplifier, at least one RF filter, at least one RF duplexer, at least one RF diplexer, the like, or any combination thereof. In one embodiment of the RF system control circuitry 14, the RF system control circuitry 14 is RF transceiver circuitry, which may include the envelope control circuitry 29, the RF modulator 30, an RF transceiver IC, baseband controller circuitry, the like, or any combination thereof.



FIG. 2 is a graph illustrating the RF transmit signal RFT and the envelope power supply voltage EPV shown in FIG. 1 according to one embodiment of the RF transmit signal RFT and the envelope power supply voltage EPV. In one embodiment of the RF input signal RFI (FIG. 1), the RF input signal RFI (FIG. 1) is amplitude modulated. As such, the RF transmit signal RFT is also amplitude modulated, as illustrated in FIG. 2. Since the amplitude of the RF transmit signal RFT is modulated, the amplitude of the RF transmit signal RFT traverses within an envelope of the RF transmit signal RFT. For proper operation of the RF PA 24 (FIG. 1), the envelope power supply voltage EPV must be high enough to accommodate the envelope of the RF transmit signal RFT. However, to increase efficiency in the RF PA 24 (FIG. 1), the envelope power supply voltage EPV at least partially tracks the envelope of the RF transmit signal RFT as illustrated in FIG. 2. This tracking by the envelope power supply voltage EPV is called envelope tracking.


In this regard, in one embodiment of the envelope power supply control signal VRMP (FIG. 1), since the envelope power supply control signal VRMP (FIG. 1) is representative of the setpoint of the envelope power supply voltage EPV, the envelope power supply control signal VRMP (FIG. 1) is amplitude modulated to provide at least partial envelope tracking of the RF transmit signal RFT by causing the envelope power supply voltage EPV to be amplitude modulated.


In one embodiment, of the RF communications system 10 illustrated in FIG. 1, the setpoint of the envelope power supply voltage EPV has been constrained to limit a noise conversion gain (NCG) of the RF PA 24 to not exceed a target NCG. As such, the setpoint of the envelope power supply voltage EPV that has been constrained is a constrained setpoint. The NCG of the RF PA 24 is a metric of how the RF PA 24 converts noise in the envelope power supply voltage EPV to noise in the RF transmit signal RFT. As such, the NCG is a function of both the input power PIN and the envelope power supply voltage EPV.


In one embodiment of the RF communications system 10, a parameterized relationship between the input power PIN and the envelope power supply voltage EPV is used to provide the constrained setpoint to limit the NCG of the RF PA 24 to not exceed the target NCG. Limiting the NCG of the RF PA 24 may provide consistent part-to-part RF performance of the RF PA 24. Therefore, in addition to limiting the NCG of the RF PA 24 to not exceed the target NCG, the parameterized relationship may be used to optimize other RF parameters of the RF PA 24. As such, in a first embodiment of the parameterized relationship, the constrained setpoint is pre-distorted to increase linearity of the RF PA 24. In a second embodiment of the parameterized relationship, the constrained setpoint is pre-distorted to decrease intermodulation distortion of the RF PA 24. In a third embodiment of the parameterized relationship, the constrained setpoint is pre-distorted to maintain approximately constant voltage gain of the RF PA 24. In addition, the parameterized relationship may also be used to provide a secondary criterion. For example, in the third embodiment of the parameterized relationship, the constrained setpoint is pre-distorted to maintain approximately constant voltage gain of the RF PA 24 and the constrained setpoint is further pre-distorted to a specific target voltage gain of the RF PA 24.


In one embodiment of the parameterized relationship, the parameterized relationship is represented by at least one mathematical equation. In an alternate embodiment of the parameterized relationship, the parameterized relationship is represented by at least one look-up table (LUT). In another embodiment of the parameterized relationship, the parameterized relationship is represented by at least one mathematical equation and at least one LUT.


In a first embodiment of the RF communications system 10, the RF system control circuitry 14 constrains the setpoint of the envelope power supply voltage EPV, such that the envelope power supply control signal VRMP is representative of the constrained setpoint of the envelope power supply voltage EPV. In one embodiment of the RF system control circuitry 14, the RF system control circuitry 14 provides the parameterized relationship between the input power PIN and the envelope power supply voltage EPV. As such, the RF system control circuitry 14 pre-distorts the constrained setpoint to optimize the other RF parameters of the RF PA 24, as mentioned above.


In one embodiment of the RF system control circuitry 14, the RF system control circuitry 14 is RF transceiver circuitry. In this regard, the RF transceiver circuitry provides the constrained setpoint of the envelope power supply voltage EPV to the envelope tracking power supply 26 via the envelope power supply control signal VRMP. Further, the RF transceiver circuitry may pre-distort the constrained setpoint to optimize the other RF parameters of the RF PA 24, as mentioned above.


In a second embodiment of the RF communications system 10, the transmitter control circuitry 22 constrains the setpoint of the envelope power supply voltage EPV after receiving the envelope power supply control signal VRMP from the RF system control circuitry 14. In one embodiment of the transmitter control circuitry 22, the transmitter control circuitry 22 provides the parameterized relationship between the input power PIN and the envelope power supply voltage EPV. As such, the transmitter control circuitry 22 pre-distorts the constrained setpoint to optimize the other RF parameters of the RF PA 24, as mentioned above.


In this regard, the envelope power supply control signal VRMP is representative of the setpoint of the envelope power supply voltage EPV before any NCG noise constraints or pre-distortions have been applied. In this regard, the transmitter control circuitry 22 provides the constrained setpoint of the envelope power supply voltage EPV to the envelope tracking power supply 26. As such, the RF system control circuitry 14 provides an unconstrained setpoint of the envelope power supply voltage EPV to the transmitter control circuitry 22 via the envelope power supply control signal VRMP, and the transmitter control circuitry 22 constrains the setpoint of the envelope power supply voltage EPV using the envelope power supply control signal VRMP.


In a third embodiment of the RF communications system 10, the RF system control circuitry 14 partially constrains the setpoint of the envelope power supply voltage EPV, such that the envelope power supply control signal VRMP is representative of a partially constrained setpoint of the envelope power supply voltage EPV, and the transmitter control circuitry 22 partially constrains the setpoint of the envelope power supply voltage EPV after receiving the envelope power supply control signal VRMP.



FIG. 3 shows the RF communications system 10 according to an alternate embodiment of the RF communications system 10. The RF communications system 10 illustrated in FIG. 3 is similar to the RF communications system 10 illustrated in FIG. 1, except in the RF communications system 10 illustrated in FIG. 3, the RF transmitter circuitry 12 further includes a digital communications interface 31, which is coupled between the transmitter control circuitry 22 and a digital communications bus 32. The digital communications bus 32 is also coupled to the RF system control circuitry 14. As such, the RF system control circuitry 14 provides the envelope power supply control signal VRMP (FIG. 1) and the transmitter configuration signal PACS (FIG. 1) to the transmitter control circuitry 22 via the digital communications bus 32 and the digital communications interface 31.


In one embodiment of the RF communications system 10, the RF system control circuitry 14 is the RF transceiver circuitry, which provides the constrained setpoint of the envelope power supply voltage EPV to the envelope tracking power supply 26 via the envelope power supply control signal VRMP. Further, the RF transceiver circuitry provides the envelope power supply control signal VRMP (FIG. 1) and the transmitter configuration signal PACS (FIG. 1) to the transmitter control circuitry 22 via the digital communications bus 32 and the digital communications interface 31.



FIG. 4 shows details of the envelope tracking power supply 26 illustrated in FIG. 1 according to one embodiment of the envelope tracking power supply 26. The envelope tracking power supply 26 includes power supply control circuitry 34, a parallel amplifier 36, and a switching supply 38. The power supply control circuitry 34 is coupled to the transmitter control circuitry 22, the parallel amplifier 36 is coupled to the power supply control circuitry 34, and the switching supply 38 is coupled to the power supply control circuitry 34. The transmitter control circuitry 22 provides the constrained setpoint of the envelope power supply voltage EPV (FIG. 1) to the power supply control circuitry 34.


The power supply control circuitry 34 controls the parallel amplifier 36 and the switching supply 38 based on the constrained setpoint of the envelope power supply voltage EPV (FIG. 1). The parallel amplifier 36 and the switching supply 38 provide the envelope power supply voltage EPV (FIG. 1), such that the parallel amplifier 36 partially provides the envelope power supply voltage EPV (FIG. 1) and the switching supply 38 partially provides the envelope power supply voltage EPV (FIG. 1). The switching supply 38 may provide power more efficiently than the parallel amplifier 36. However, the parallel amplifier 36 may provide the envelope power supply voltage EPV (FIG. 1) more accurately than the switching supply 38. As such, the parallel amplifier 36 regulates the envelope power supply voltage EPV (FIG. 1) based on the constrained setpoint of the envelope power supply voltage EPV (FIG. 1) and the switching supply 38 operates to drive an output current from the parallel amplifier 36 toward zero to increase efficiency. In this regard, the parallel amplifier 36 behaves like a voltage source and the switching supply 38 behaves like a current source.


As previously mentioned, in one embodiment of the RF communications system 10 illustrated in FIG. 1, the RF PA 24 receives and amplifies the RF input signal RFI to provide the RF transmit signal RFT using the envelope power supply voltage EPV, which provides power for amplification. As such, in a first embodiment of the envelope power supply voltage EPV, a bandwidth of the envelope power supply voltage EPV is greater than 10 megahertz. In a second embodiment of the envelope power supply voltage EPV, a bandwidth of the envelope power supply voltage EPV is greater than 20 megahertz. In a third embodiment of the envelope power supply voltage EPV, a bandwidth of the envelope power supply voltage EPV is greater than 30 megahertz. In a fourth embodiment of the envelope power supply voltage EPV, a bandwidth of the envelope power supply voltage EPV is greater than 40 megahertz. In a fifth embodiment of the envelope power supply voltage EPV, a bandwidth of the envelope power supply voltage EPV is greater than 50 megahertz. In an alternate embodiment of the envelope power supply voltage EPV, a bandwidth of the envelope power supply voltage EPV is less than 100 megahertz.



FIG. 5 shows the RF communications system 10 according to another embodiment of the RF communications system 10. The RF communications system 10 illustrated in FIG. 5 is similar to the RF communications system 10 illustrated in FIG. 1, except in the RF communications system 10 illustrated in FIG. 5, the RF system control circuitry 14 includes look-up table (LUT)-based constrained setpoint data 40, which may be used by the RF system control circuitry 14 to provide the constrained setpoint. As such, the constrained setpoint is based on the LUT-based constrained setpoint data 40. Further, the RF system control circuitry 14 provides the constrained setpoint to the envelope tracking power supply 26 via the envelope power supply control signal VRMP.


In one embodiment of the RF system control circuitry 14, the RF system control circuitry 14 is the RF transceiver circuitry. As such, the RF transceiver circuitry includes the LUT-based constrained setpoint data 40, which may be used by the RF transceiver circuitry to provide the constrained setpoint. As such, the constrained setpoint is based on the LUT-based constrained setpoint data 40. Further, the RF transceiver circuitry provides the constrained setpoint to the envelope tracking power supply 26 via the envelope power supply control signal VRMP.



FIG. 6 shows the RF communications system 10 according to a further embodiment of the RF communications system 10. The RF communications system 10 illustrated in FIG. 6 is similar to the RF communications system 10 illustrated in FIG. 1, except in the RF communications system 10 illustrated in FIG. 6, the transmitter control circuitry 22 includes the LUT-based constrained setpoint data 40, which may be used by the transmitter control circuitry 22 to provide the constrained setpoint. As such, the constrained setpoint is based on the LUT-based constrained setpoint data 40.



FIG. 7 shows an RF PA calibration environment according to one embodiment of the RF PA calibration environment. The RF PA calibration environment includes RF calibration circuitry 42 and a calibration RF PA 44. During a calibration of the calibration RF PA 44, the RF calibration circuitry 42 provides a calibration RF input signal CRFI and a calibration envelope power supply signal CEPS to the calibration RF PA 44. The calibration RF PA 44 receives and amplifies the calibration RF input signal CRFI to provide a calibration RF output signal CRFO using the calibration envelope power supply signal CEPS to provide power for amplification. The RF calibration circuitry 42 receives the calibration RF output signal CRFO.


During the calibration of the calibration RF PA 44, the RF calibration circuitry 42 varies a magnitude of the calibration RF input signal CRFI and varies a magnitude of the calibration envelope power supply signal CEPS and measures a resulting magnitude of the calibration RF output signal CRFO. The magnitude of the calibration RF input signal CRFI is associated with an input power level and the magnitude of the calibration RF output signal CRFO is associated with an output power level. In this regard, the RF calibration circuitry 42 functionally characterizes the calibration RF PA 44 based on the magnitudes of the calibration RF input signal CRFI, the calibration envelope power supply signal CEPS, and the calibration RF output signal CRFO. Specifically, the RF calibration circuitry 42 characterizes the NCG of the calibration RF PA 44 and provides the LUT-based constrained setpoint data 40 based on the NCG characterization of the calibration RF PA 44.


In general, the LUT-based constrained setpoint data 40 is based on a functional characterization of the calibration RF PA 44. In one embodiment of the RF PA calibration environment, the RF PA calibration environment is external to the RF communications system 10 (FIGS. 5 and 6). In an alternate embodiment of the RF PA calibration environment, the RF PA calibration environment includes the RF communications system 10 (FIGS. 5 and 6). In another embodiment of the RF PA calibration environment, the RF system control circuitry 14 (FIG. 5) provides the RF PA calibration environment, such that the calibration RF PA 44 is the RF PA 24 (FIG. 5). In general, in one embodiment of the calibration RF PA 44, the calibration RF PA 44 is the RF PA 24 (FIGS. 5 and 6). In an alternate embodiment of the calibration RF PA 44, the calibration RF PA 44 is not the RF PA 24 (FIGS. 5 and 6).



FIG. 8 is a graph illustrating an RF transmit band 46 associated with the RF transmit signal RFT and an RF receive band 48 associated with the RF receive signal RFR illustrated in FIG. 1 according to one embodiment of the RF communications system 10. The RF transmit signal RFT (FIG. 1) has a transmit carrier frequency TCF and the RF receive signal RFR (FIG. 1) has a receive carrier frequency RCF. An RF duplex frequency 50 is based on a difference between the transmit carrier frequency TCF and the receive carrier frequency RCF.



FIG. 9 is a graph illustrating a relationship between the envelope power supply voltage EPV and an input power PIN to the RF PA 24 illustrated in FIG. 1 according to one embodiment of the RF communications system 10. The embodiments illustrated in FIGS. 9, 10, 11, and 12 are exemplary and make no general restrictions regarding a relationship between the input power PIN, the envelope power supply voltage EPV, and NCG other than the concept that NCG may be used as a constraint, which may be used to put some type(s) of noise under control. In this regard, both FIG. 1 and FIG. 9 may be relevant to the information presented below. Further, FIG. 9 illustrates a DC operating point VDCO. A voltage gain VGAIN of the RF PA 24 is defined as a magnitude of an output voltage VOUT of the RF transmit signal RFT divided by a magnitude of an input voltage VIN of the RF input signal RFI, as shown in EQ. 1 below.

VGAIN=VOUT/VIN, or VOUT=VGAIN*VIN.  EQ. 1:


When the RF PA 24 operates in a non-saturated manner, the envelope power supply voltage EPV is high enough to provide operating headroom. As such, within a preferred operating range of the RF PA 24, the voltage gain VGAIN does not significantly change due to changes in the envelope power supply voltage EPV. However, providing the operating headroom may decrease efficiency of the RF PA 24. As a result, envelope tracking is often used to decrease the operating headroom and increase efficiency. Further, in one embodiment of the RF PA 24, the RF PA 24 operates with at least partial saturation to increase efficiency. When operating with partial saturation, the envelope power supply voltage EPV is not high enough to allow completely linear operation of the RF PA 24. As a result, the voltage gain VGAIN is reduced.


In this regard, FIG. 9 shows Constant Gain Contours of the RF PA 24. Each Constant Gain Contour represents a constant voltage gain VGAIN of the RF PA 24. As such, for each Constant Gain Contour, as the input power PIN increases, the envelope power supply voltage EPV also increases to maintain the constant voltage gain VGAIN at the saturation level associated with the Constant Gain Contour. As a result, different saturation levels of the RF PA 24 are associated with different Constant Gain Contours, such that each Constant Gain Contour is associated with a respective saturation level. As the RF PA 24 is operated into deeper levels of saturation, the envelope power supply voltage EPV levels needed to maintain the constant voltage gain VGAIN are reduced. Therefore, the Constant Gain Contours with higher envelope power supply voltage EPV levels illustrated in FIG. 9 are associated with lower saturation levels than the Constant Gain Contours with lower envelope power supply voltage EPV levels.


Once an Constant Gain Contour is selected, the voltage gain VGAIN may be linearized around the DC operating point VDCO, as shown in EQ. 2 below.

VGAIN=VGAIN(at VDCO)+[(dVGAIN/dEPV)*(EPV-VDCO)].  EQ. 2:


In general, when operating the RF PA 24 in partial saturation, the voltage gain VGAIN is dependent on both the input power PIN and the envelope power supply voltage EPV. As such, noise in the envelope power supply voltage EPV, such as switching noise from the switching supply 38, modulates the voltage gain VGAIN, thereby introducing noise in the RF transmit signal RFT. As saturation levels increase, efficiency of the RF PA 24 may increase, but the resulting noise in the RF transmit signal RFT also increases. Therefore, there is a tradeoff between efficiency of the RF PA 24 and noise in the RF transmit signal RFT. Noise in the RF transmit signal RFT may be problematic in meeting RF transmit spectrum requirements, in meeting Adjacent Channel Leakage Ratio (ACLR) requirements, in meeting communications protocol requirements, by interfering with RF receive operations, the like, or any combination thereof.


As previously mentioned, the NCG of the RF PA 24 is a metric of how the RF PA 24 converts noise in the envelope power supply voltage EPV to noise in the RF transmit signal RFT. As such, the NCG is a function of both the input power PIN and the envelope power supply voltage EPV.


In one embodiment of the RF PA 24, the conversion of the noise in the envelope power supply voltage EPV to the noise in the RF transmit signal RFT is at least partially as a result of the partial saturation of the RF PA 24. Further, in one embodiment of the RF PA 24, the conversion of the noise in the envelope power supply voltage EPV to the noise in the RF transmit signal RFT is at least partially as a result of the physics of the semiconductor device that provides the RF PA 24.


When the RF PA 24 operates in partial saturation, the RF PA 24 partially functions as an RF mixer, which mixes the envelope power supply voltage EPV and the RF input signal RFI, which has the input voltage VIN. Therefore, for purposes of illustration, the noise in the envelope power supply voltage EPV is represented as a continuous wave (CW) having a noise amplitude NA and a noise frequency NF, and the RF input signal RFI is represented as a CW having an input amplitude RFA and an input frequency RFF, as shown in EQ. 3 and EQ. 4, respectively below.

EPV=VDCO+(NA)sin [2π(NF)t].  EQ. 3:
VIN=(RFA)sin [2π(RFF)t].  EQ. 4:


Substituting EQ. 4 into EQ. 1 provides EQ. 5, as shown below.

VOUT=VGAIN*VIN=VGAIN*[(RFA)sin [2π(RFF)t].  EQ. 5:


EQ. 2 may be re-arranged into EQ. 6, EQ. 7, and EQ. 8, as shown below.

VGAIN=(Part 1)+(Part 2).  EQ. 6:
Part 1=VGAIN(at VDCO).  EQ. 7:
Part 2=[(dVGAIN/dEPV)*(EPV-VDCO)].  EQ. 8:


Substituting EQ. 3 into EQ. 8 provides EQ. 9, as shown below.













Part





2

=





[



VGAIN



/




EPV


]



[

VDCO
+


(
NA
)


sin





2


π


(
NF
)



t

-
VDCO

]


.







=




[


(



VGAIN



/




EPV


)

*

(
NA
)


sin





2


π


(
NF
)



t

]

.









EQ
.




9



:








Substituting EQ. 6 into EQ. 5 provides EQ. 10, as shown below.












VOUT
=




(

Part





A





of





VOUT

)

+


(

Part





B





of





VOUT

)

.








=




[


(

Part





1

)

+

(

Part





2

)


]

*

[


(

R





F





A

)




sin


[

2


π


(

R





F





F

)



t

]


.












EQ
.




10



:








EQ. 10 is separated into EQ. 11 and EQ. 12, as shown below.













Part





A





of





VOUT

=




(

Part





1

)

*

[


(

R





F





A

)




sin


[

2


π


(

R





F





F

)



t

]


.










=




[

VGAIN


(

at





VDCO

)


]

*

[


(

R





F





A

)




sin


[

2


π


(

R





F





F

)



t

]


.












EQ
.




11



:











Part





B





of





VOUT

=




(

Part





2

)

*

[


(

R





F





A

)




sin


[

2


π


(

R





F





F

)



t

]


.










=




[

(



VGAIN



/




EPV


)

]

*

[


(
NA
)


sin





2


π


(

N





F

)



t

]

*










[


(

R





F





A

)




sin


[

2


π


(

R





F





F

)



t

]


.











EQ
.




12



:








Part A of VOUT, as shown in EQ. 11, includes only an RF frequency RFF term and does not contain any Noise Frequency NF terms. As such, EQ. 11 is indicative of no contribution to the NCG of the RF PA 24 illustrated in FIG. 1. Therefore, Part A of VOUT is ignored. However, Part B of VOUT, as shown in EQ. 12, includes both an RF frequency RFF term and a Noise Frequency NF term. As such, EQ. 12 is indicative of contribution to the NCG of the RF PA 24 illustrated in FIG. 1.


A product trigonometric identity is provided in EQ. 13, as shown below.

(sin A)(sin B)=[cos(A−B)−cos(A+B)]/2.  EQ. 13:


Combining EQ. 12 into EQ. 13 provides EQ. 14, as shown below.

Part B of VOUT=[(dVGAIN/dEPV)]*(RFA)*(NA)*[cos 2π(RFF−NF)t−cos 2π(RFF−NF)t]/2.  EQ. 14:


From EQ. 14, the RF transmit signal RFT includes noise from the envelope power supply voltage EPV at both a sum of and a difference between the input frequency RFF and the noise frequency NF. In an exemplary embodiment of the NCG, the NCG is related to a ratio of power of the noise from the envelope power supply voltage EPV in the RF transmit signal RFT divided by the power of the noise in the envelope power supply voltage EPV. For example, in a first exemplary embodiment of the NCG, the NCG is related to the noise from the envelope power supply voltage EPV in the RF transmit signal RFT at the difference between the input frequency RFF and the noise frequency NF. In a second exemplary embodiment of the NCG, the NCG is related to the noise from the envelope power supply voltage EPV in the RF transmit signal RFT at the sum of the input frequency RFF and the noise frequency NF.


In one embodiment of the RF communications system 10, the RF transmit signal RFT has the transmit carrier frequency TCF (FIG. 8) and the noise frequency NF is about equal to the RF duplex frequency 50 (FIG. 8). As such, a sum of the input frequency RFF and the noise frequency NF may be about equal to the receive carrier frequency RCF (FIG. 8). As a result, since a magnitude of the RF receive signal RFR may be much smaller than a magnitude of the RF transmit signal RFT, the noise from the envelope power supply voltage EPV in the RF transmit signal RFT may interfere with proper reception of the RF receive signal RFR. Therefore, the NCG and the target NCG may be based on the noise from the envelope power supply voltage EPV in the RF transmit signal RFT at the sum of the input frequency RFF and the noise frequency NF.


In the embodiment of the RF communications system 10 just presented, the noise in the envelope power supply voltage EPV was represented as a continuous wave (CW). However, the noise in the envelope power supply voltage EPV introduced from the switching supply 38 may have multiple harmonics of a fundamental switching frequency. As a result, the NCG, the target NCG, or both may be based on noise at any or all of the harmonics of the fundamental switching frequency.



FIG. 10 is a graph illustrating a relationship between the envelope power supply voltage EPV and the input power PIN to the RF PA 24 illustrated in FIG. 1 according to an alternate embodiment of the RF communications system 10. The graph illustrated in FIG. 10 is similar to the graph illustrated in FIG. 9, except the graph illustrated in FIG. 10 includes the Constant Gain Contours illustrated in FIG. 9 and further includes Constant NCG Contours. Each Constant NCG Contour represents a constant NCG of the RF PA 24. As such, for each Constant NCG Contour, as the input power PIN increases, the envelope power supply voltage EPV also increases to maintain a constant NCG. As a result, different NCGs of the RF PA 24 are associated with different Constant NCG Contours, such that each Constant NCG Contour is associated with a respective NCG. As previously mentioned, as the RF PA 24 is operated into deeper levels of saturation, the envelope power supply voltage EPV levels needed to maintain the constant voltage gain VGAIN are reduced. However, the deeper levels of saturation tend to increase the NCG. Therefore, the Constant NCG Contours with higher envelope power supply voltage EPV levels illustrated in FIG. 10 are associated with lower NCGs than the Constant NCG Contours with lower envelope power supply voltage EPV levels.


In one embodiment of the RF communications system 10, one of the Constant NCG Contours is a Target Constant NCG Contour 52, which is associated with the target NCG. In one embodiment of the RF communications system 10, the NCG of the RF PA 24 is equal to the target NCG when an output power from the RF PA 24 is about equal to a target output power from the RF PA 24. In one embodiment of the target output power, the target output power is a rated average output power of the RF PA 24 during envelope tracking. In an alternate embodiment of the target output power, the target output power is a maximum of a rated range of average output power of the RF PA 24 during envelope tracking.



FIG. 11 is a graph illustrating a relationship between the envelope power supply voltage EPV and the input power PIN to the RF PA 24 illustrated in FIG. 1 according to an additional embodiment of the RF communications system 10. The graph illustrated in FIG. 11 is similar to the graph illustrated in FIG. 10, except the graph illustrated in FIG. 11 further shows a target envelope power supply voltage TEPV. As such, in one embodiment of the RF communications system 10, the NCG of the RF PA 24 is equal to the target NCG when the envelope power supply voltage EPV is about equal to the target envelope power supply voltage TEPV.



FIG. 12 is a graph illustrating a relationship between the envelope power supply voltage EPV and the input power PIN to the RF PA 24 illustrated in FIG. 1 according to another embodiment of the RF communications system 10. The graph illustrated in FIG. 12 is similar to the graph illustrated in FIG. 10, except the graph illustrated in FIG. 12 further shows a target input power TPIN. As such, in one embodiment of the RF communications system 10, the NCG of the RF PA 24 is equal to the target NCG when the input power PIN is about equal to the target input power TPIN.


Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.

Claims
  • 1. Circuitry comprising: envelope control circuitry configured to provide an envelope power supply control signal; anda radio frequency (RF) modulator configured to provide an RF input signal, wherein: an RF power amplifier (PA) is configured to receive and amplify the RF input signal to provide an RF transmit signal using an envelope power supply voltage;an envelope tracking power supply is configured to provide the envelope power supply voltage based on a setpoint, which has been constrained to limit a noise conversion gain (NCG) of the RF PA to not exceed a target NCG, wherein the envelope power supply voltage at least partially tracks an envelope of the RF transmit signal; andRF transceiver circuitry comprises the envelope control circuitry and the RF modulator, such that the setpoint, which has been constrained to limit the NCG of the RF PA, is a constrained setpoint, such that the RF transceiver circuitry is configured to provide the constrained setpoint to the envelope tracking power supply via the envelope power supply control signal.
  • 2. The circuitry of claim 1 wherein the RF transceiver circuitry comprises look-up table-based constrained setpoint data, such that the constrained setpoint is based on the look-up table-based constrained setpoint data.
  • 3. The circuitry of claim 2 wherein the look-up table-based constrained setpoint data is based on a functional characterization of a calibration RF PA.
  • 4. The circuitry of claim 3 wherein the calibration RF PA is the RF PA.
  • 5. The circuitry of claim 1 wherein the RF transceiver circuitry is further configured to provide the envelope power supply control signal to the envelope tracking power supply via a digital communications bus and a digital communications interface.
  • 6. The circuitry of claim 1 wherein the RF transceiver circuitry is further configured to pre-distort the constrained setpoint to increase linearity of the RF PA.
  • 7. The circuitry of claim 1 wherein the RF transceiver circuitry is further configured to pre-distort the constrained setpoint to decrease intermodulation distortion of the RF PA.
  • 8. The circuitry of claim 1 wherein the RF transceiver circuitry is further configured to pre-distort the constrained setpoint to maintain approximately constant voltage gain of the RF PA.
  • 9. Circuitry comprising: a radio frequency (RF) power amplifier (PA) configured to receive and amplify an RF input signal to provide an RF transmit signal using an envelope power supply voltage; andan envelope tracking power supply configured to provide the envelope power supply voltage based on a setpoint, which has been constrained to limit a noise conversion gain (NCG) of the RF PA to not exceed a target NCG, wherein the envelope power supply voltage at least partially tracks an envelope of the RF transmit signal.
  • 10. The circuitry of claim 9 wherein the envelope tracking power supply comprises a parallel amplifier and a switching supply, such that: the parallel amplifier is configured to partially provide and regulate the envelope power supply voltage based on the setpoint; andthe switching supply is configured to partially provide the envelope power supply voltage and drive an output current from the parallel amplifier toward zero.
  • 11. The circuitry of claim 9 wherein the setpoint, which has been constrained to limit the NCG of the RF PA, is a constrained setpoint, and the circuitry further comprises transmitter control circuitry configured to constrain an unconstrained setpoint of the envelope power supply voltage to provide the constrained setpoint to the envelope tracking power supply.
  • 12. The circuitry of claim 11 wherein the transmitter control circuitry comprises look-up table-based constrained setpoint data, such that the constrained setpoint is based on the look-up table-based constrained setpoint data.
  • 13. The circuitry of claim 12 wherein the look-up table-based constrained setpoint data is based on a functional characterization of a calibration RF PA.
  • 14. The circuitry of claim 13 wherein the calibration RF PA is the RF PA.
  • 15. The circuitry of claim 11 wherein RF system control circuitry is configured to provide the unconstrained setpoint of the envelope power supply voltage to the transmitter control circuitry via an envelope power supply control signal.
  • 16. The circuitry of claim 15 further comprising the RF system control circuitry.
  • 17. The circuitry of claim 11 wherein the transmitter control circuitry is further configured to pre-distort the constrained setpoint to increase linearity of the RF PA.
  • 18. The circuitry of claim 11 wherein the transmitter control circuitry is further configured to pre-distort the constrained setpoint to decrease intermodulation distortion of the RF PA.
  • 19. The circuitry of claim 11 wherein the transmitter control circuitry is further configured to pre-distort the constrained setpoint to maintain approximately constant voltage gain of the RF PA.
  • 20. The circuitry of claim 9 wherein the NCG of the RF PA is equal to the target NCG when an input power to the RF PA is about equal to a target input power.
  • 21. The circuitry of claim 9 wherein the NCG of the RF PA is equal to the target NCG when the envelope power supply voltage is about equal to a target envelope power supply voltage.
  • 22. The circuitry of claim 9 wherein the NCG of the RF PA is equal to the target NCG when an output power from the RF PA is about equal to a target output power.
  • 23. The circuitry of claim 22 wherein the target output power is a rated average output power of the RF PA during envelope tracking.
  • 24. The circuitry of claim 22 wherein the target output power is a maximum of a rated range of average output power of the RF PA during envelope tracking.
  • 25. The circuitry of claim 9 wherein a bandwidth of the envelope power supply voltage is greater than 20 megahertz.
  • 26. A method comprising: receiving and amplifying a radio frequency (RF) input signal to provide an RF transmit signal using an envelope power supply voltage; andproviding the envelope power supply voltage based on a setpoint, which has been constrained to limit a noise conversion gain (NCG) of an RF power amplifier (PA) to not exceed a target NCG, wherein the envelope power supply voltage at least partially tracks an envelope of the RF transmit signal.
RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patent application No. 61/783,897, filed Mar. 14, 2013, the disclosure of which is incorporated herein by reference in its entirety.

US Referenced Citations (311)
Number Name Date Kind
3969682 Rossum Jul 1976 A
3980964 Grodinsky Sep 1976 A
4587552 Chin May 1986 A
4692889 McNeely Sep 1987 A
4831258 Paulk et al. May 1989 A
4996500 Larson et al. Feb 1991 A
5099203 Weaver et al. Mar 1992 A
5146504 Pinckley Sep 1992 A
5187396 Armstrong, II et al. Feb 1993 A
5311309 Ersoz et al. May 1994 A
5317217 Rieger et al. May 1994 A
5351087 Christopher et al. Sep 1994 A
5414614 Fette et al. May 1995 A
5420643 Romesburg et al. May 1995 A
5457620 Dromgoole Oct 1995 A
5486871 Filliman et al. Jan 1996 A
5532916 Tamagawa Jul 1996 A
5541547 Lam Jul 1996 A
5581454 Collins Dec 1996 A
5646621 Cabler et al. Jul 1997 A
5715526 Weaver, Jr. et al. Feb 1998 A
5767744 Irwin et al. Jun 1998 A
5822318 Tiedemann, Jr. et al. Oct 1998 A
5898342 Bell Apr 1999 A
5905407 Midya May 1999 A
5936464 Grondahl Aug 1999 A
6043610 Buell Mar 2000 A
6043707 Budnik Mar 2000 A
6055168 Kotowski et al. Apr 2000 A
6070181 Yeh May 2000 A
6118343 Winslow et al. Sep 2000 A
6133777 Savelli Oct 2000 A
6141541 Midya et al. Oct 2000 A
6147478 Skelton et al. Nov 2000 A
6198645 Kotowski et al. Mar 2001 B1
6204731 Jiang et al. Mar 2001 B1
6256482 Raab Jul 2001 B1
6300826 Mathe et al. Oct 2001 B1
6313681 Yoshikawa Nov 2001 B1
6348780 Grant Feb 2002 B1
6400775 Gourgue et al. Jun 2002 B1
6483281 Hwang Nov 2002 B2
6559689 Clark May 2003 B1
6566935 Renous May 2003 B1
6583610 Groom et al. Jun 2003 B2
6617930 Nitta Sep 2003 B2
6621808 Sadri Sep 2003 B1
6624712 Cygan et al. Sep 2003 B1
6658445 Gau et al. Dec 2003 B1
6681101 Eidson et al. Jan 2004 B1
6690652 Sadri Feb 2004 B1
6701141 Lam Mar 2004 B2
6703080 Reyzelman et al. Mar 2004 B2
6728163 Gomm et al. Apr 2004 B2
6744151 Jackson et al. Jun 2004 B2
6819938 Sahota Nov 2004 B2
6885176 Librizzi Apr 2005 B2
6958596 Sferrazza et al. Oct 2005 B1
6995995 Zeng et al. Feb 2006 B2
7038536 Cioffi et al. May 2006 B2
7043213 Robinson et al. May 2006 B2
7053718 Dupuis et al. May 2006 B2
7058373 Grigore Jun 2006 B2
7099635 McCune Aug 2006 B2
7164893 Leizerovich et al. Jan 2007 B2
7170341 Conrad et al. Jan 2007 B2
7200365 Watanabe et al. Apr 2007 B2
7233130 Kay Jun 2007 B1
7253589 Potanin et al. Aug 2007 B1
7254157 Crotty et al. Aug 2007 B1
7262658 Ramaswamy et al. Aug 2007 B2
7279875 Gan et al. Oct 2007 B2
7304537 Kwon et al. Dec 2007 B2
7348847 Whittaker Mar 2008 B2
7394233 Trayling et al. Jul 2008 B1
7405618 Lee et al. Jul 2008 B2
7411316 Pai Aug 2008 B2
7414330 Chen Aug 2008 B2
7515885 Sander et al. Apr 2009 B2
7528807 Kim et al. May 2009 B2
7529523 Young et al. May 2009 B1
7539466 Tan et al. May 2009 B2
7595569 Amerom et al. Sep 2009 B2
7609114 Hsieh et al. Oct 2009 B2
7615979 Caldwell Nov 2009 B2
7627622 Conrad et al. Dec 2009 B2
7646108 Paillet et al. Jan 2010 B2
7653366 Grigore Jan 2010 B2
7679433 Li Mar 2010 B1
7684216 Choi et al. Mar 2010 B2
7696735 Oraw et al. Apr 2010 B2
7715811 Kenington May 2010 B2
7724837 Filimonov et al. May 2010 B2
7755431 Sun Jul 2010 B2
7764060 Wilson Jul 2010 B2
7773691 Khlat et al. Aug 2010 B2
7777459 Williams Aug 2010 B2
7782036 Wong et al. Aug 2010 B1
7783269 Vinayak et al. Aug 2010 B2
7800427 Chae et al. Sep 2010 B2
7805115 McMorrow et al. Sep 2010 B1
7852150 Arknaes-Pedersen Dec 2010 B1
7856048 Smaini et al. Dec 2010 B1
7859336 Markowski et al. Dec 2010 B2
7880547 Lee et al. Feb 2011 B2
7894216 Melanson Feb 2011 B2
7898268 Bernardon et al. Mar 2011 B2
7898327 Nentwig Mar 2011 B2
7907010 Wendt et al. Mar 2011 B2
7915961 Li Mar 2011 B1
7920023 Vinayak et al. Apr 2011 B2
7923974 Martin et al. Apr 2011 B2
7965140 Takahashi Jun 2011 B2
7994864 Chen et al. Aug 2011 B2
8000117 Petricek Aug 2011 B2
8008970 Homol et al. Aug 2011 B1
8022761 Drogi et al. Sep 2011 B2
8026765 Giovannotto Sep 2011 B2
8044639 Tamegai et al. Oct 2011 B2
8054126 Witchard Nov 2011 B2
8068622 Melanson et al. Nov 2011 B2
8081199 Takata et al. Dec 2011 B2
8093951 Zhang et al. Jan 2012 B1
8159297 Kumagai Apr 2012 B2
8164388 Iwamatsu Apr 2012 B2
8174313 Vice May 2012 B2
8183917 Drogi et al. May 2012 B2
8183929 Grondahl May 2012 B2
8198941 Lesso Jun 2012 B2
8204456 Xu et al. Jun 2012 B2
8242813 Wile et al. Aug 2012 B1
8253485 Clifton Aug 2012 B2
8253487 Hou et al. Aug 2012 B2
8274332 Cho et al. Sep 2012 B2
8289084 Morimoto et al. Oct 2012 B2
8362837 Koren et al. Jan 2013 B2
8541993 Notman et al. Sep 2013 B2
8542061 Levesque et al. Sep 2013 B2
8548398 Baxter et al. Oct 2013 B2
8558616 Shizawa et al. Oct 2013 B2
8588713 Khlat Nov 2013 B2
8611402 Chiron Dec 2013 B2
8618868 Khlat et al. Dec 2013 B2
8624576 Khlat et al. Jan 2014 B2
8624760 Ngo et al. Jan 2014 B2
8626091 Khlat et al. Jan 2014 B2
8638165 Shah et al. Jan 2014 B2
8648657 Rozenblit Feb 2014 B1
8659355 Henshaw et al. Feb 2014 B2
8717100 Reisner et al. May 2014 B2
8718579 Drogi et al. May 2014 B2
8718582 See et al. May 2014 B2
8725218 Brown et al. May 2014 B2
8744382 Hou et al. Jun 2014 B2
8749307 Zhu et al. Jun 2014 B2
8803605 Fowers et al. Aug 2014 B2
8824978 Briffa et al. Sep 2014 B2
8829993 Briffa et al. Sep 2014 B2
8884696 Langer Nov 2014 B2
8909175 McCallister Dec 2014 B1
8942651 Jones Jan 2015 B2
8947162 Wimpenny et al. Feb 2015 B2
8981847 Balteanu Mar 2015 B2
8994345 Wilson Mar 2015 B2
9077405 Jones et al. Jul 2015 B2
20020071497 Bengtsson et al. Jun 2002 A1
20030031271 Bozeki et al. Feb 2003 A1
20030062950 Hamada et al. Apr 2003 A1
20030137286 Kimball et al. Jul 2003 A1
20030146791 Shvarts et al. Aug 2003 A1
20030153289 Hughes et al. Aug 2003 A1
20030198063 Smyth Oct 2003 A1
20030206603 Husted Nov 2003 A1
20030220953 Allred Nov 2003 A1
20030232622 Seo et al. Dec 2003 A1
20040047329 Zheng Mar 2004 A1
20040051384 Jackson et al. Mar 2004 A1
20040124913 Midya et al. Jul 2004 A1
20040127173 Leizerovich Jul 2004 A1
20040132424 Aytur et al. Jul 2004 A1
20040184569 Challa et al. Sep 2004 A1
20040196095 Nonaka Oct 2004 A1
20040219891 Hadjichristos Nov 2004 A1
20040239301 Kobayashi Dec 2004 A1
20040266366 Robinson et al. Dec 2004 A1
20040267842 Allred Dec 2004 A1
20050008093 Matsuura et al. Jan 2005 A1
20050032499 Cho Feb 2005 A1
20050047180 Kim Mar 2005 A1
20050064830 Grigore Mar 2005 A1
20050079835 Takabayashi et al. Apr 2005 A1
20050093630 Whittaker et al. May 2005 A1
20050110562 Robinson et al. May 2005 A1
20050122171 Miki et al. Jun 2005 A1
20050156582 Redl et al. Jul 2005 A1
20050156662 Raghupathy et al. Jul 2005 A1
20050157778 Trachewsky et al. Jul 2005 A1
20050200407 Arai et al. Sep 2005 A1
20050286616 Kodavati Dec 2005 A1
20060006946 Burns et al. Jan 2006 A1
20060062324 Naito et al. Mar 2006 A1
20060097711 Brandt May 2006 A1
20060128324 Tan et al. Jun 2006 A1
20060154637 Eyries et al. Jul 2006 A1
20060178119 Jarvinen Aug 2006 A1
20060181340 Dhuyvetter Aug 2006 A1
20060220627 Koh Oct 2006 A1
20060244513 Yen et al. Nov 2006 A1
20070008804 Lu et al. Jan 2007 A1
20070014382 Shakeshaft et al. Jan 2007 A1
20070024360 Markowski Feb 2007 A1
20070024365 Ramaswamy et al. Feb 2007 A1
20070063681 Liu Mar 2007 A1
20070082622 Leinonen et al. Apr 2007 A1
20070146076 Baba Jun 2007 A1
20070159256 Ishikawa et al. Jul 2007 A1
20070182392 Nishida Aug 2007 A1
20070183532 Matero Aug 2007 A1
20070184794 Drogi et al. Aug 2007 A1
20070249304 Snelgrove et al. Oct 2007 A1
20070259628 Carmel et al. Nov 2007 A1
20070290749 Woo et al. Dec 2007 A1
20080003950 Haapoja et al. Jan 2008 A1
20080044041 Tucker et al. Feb 2008 A1
20080081572 Rofougaran Apr 2008 A1
20080104432 Vinayak et al. May 2008 A1
20080150619 Lesso et al. Jun 2008 A1
20080205095 Pinon et al. Aug 2008 A1
20080224769 Markowski et al. Sep 2008 A1
20080242246 Minnis et al. Oct 2008 A1
20080252278 Lindeberg et al. Oct 2008 A1
20080258831 Kunihiro et al. Oct 2008 A1
20080259656 Grant Oct 2008 A1
20080280577 Beukema et al. Nov 2008 A1
20090004981 Eliezer et al. Jan 2009 A1
20090045872 Kenington Feb 2009 A1
20090082006 Pozsgay et al. Mar 2009 A1
20090097591 Kim Apr 2009 A1
20090160548 Ishikawa et al. Jun 2009 A1
20090167260 Pauritsch et al. Jul 2009 A1
20090174466 Hsieh et al. Jul 2009 A1
20090184764 Markowski et al. Jul 2009 A1
20090190699 Kazakevich et al. Jul 2009 A1
20090191826 Takinami et al. Jul 2009 A1
20090218995 Ahn Sep 2009 A1
20090230934 Hooijschuur et al. Sep 2009 A1
20090261908 Markowski Oct 2009 A1
20090284235 Weng et al. Nov 2009 A1
20090289720 Takinami et al. Nov 2009 A1
20090319065 Risbo Dec 2009 A1
20100001793 Van Zeijl et al. Jan 2010 A1
20100002473 Williams Jan 2010 A1
20100019749 Katsuya et al. Jan 2010 A1
20100019840 Takahashi Jan 2010 A1
20100026250 Petty Feb 2010 A1
20100045247 Blanken et al. Feb 2010 A1
20100171553 Okubo et al. Jul 2010 A1
20100253309 Xi et al. Oct 2010 A1
20100266066 Takahashi Oct 2010 A1
20100301947 Fujioka et al. Dec 2010 A1
20100308654 Chen Dec 2010 A1
20100311365 Vinayak et al. Dec 2010 A1
20100321127 Watanabe et al. Dec 2010 A1
20100327825 Mehas et al. Dec 2010 A1
20100327971 Kumagai Dec 2010 A1
20110018626 Kojima Jan 2011 A1
20110058601 Kim et al. Mar 2011 A1
20110084760 Guo et al. Apr 2011 A1
20110109387 Lee May 2011 A1
20110148375 Tsuji Jun 2011 A1
20110234182 Wilson Sep 2011 A1
20110235827 Lesso et al. Sep 2011 A1
20110279180 Yamanouchi et al. Nov 2011 A1
20110298539 Drogi et al. Dec 2011 A1
20120025907 Koo et al. Feb 2012 A1
20120025919 Huynh Feb 2012 A1
20120034893 Baxter et al. Feb 2012 A1
20120049894 Berchtold et al. Mar 2012 A1
20120049953 Khlat Mar 2012 A1
20120068767 Henshaw et al. Mar 2012 A1
20120074916 Trochut Mar 2012 A1
20120133299 Capodivacca et al. May 2012 A1
20120139516 Tsai et al. Jun 2012 A1
20120154035 Hongo et al. Jun 2012 A1
20120154054 Kaczman et al. Jun 2012 A1
20120170334 Menegoli et al. Jul 2012 A1
20120176196 Khlat Jul 2012 A1
20120194274 Fowers et al. Aug 2012 A1
20120200354 Ripley et al. Aug 2012 A1
20120236444 Srivastava et al. Sep 2012 A1
20120244916 Brown et al. Sep 2012 A1
20120269240 Balteanu et al. Oct 2012 A1
20120299647 Honjo et al. Nov 2012 A1
20130024142 Folkmann et al. Jan 2013 A1
20130034139 Khlat et al. Feb 2013 A1
20130094553 Paek et al. Apr 2013 A1
20130135043 Hietala et al. May 2013 A1
20130147445 Levesque et al. Jun 2013 A1
20130169245 Kay et al. Jul 2013 A1
20130214858 Tournatory et al. Aug 2013 A1
20130229235 Ohnishi Sep 2013 A1
20130238913 Huang et al. Sep 2013 A1
20130307617 Khlat et al. Nov 2013 A1
20130328613 Kay et al. Dec 2013 A1
20140009200 Kay et al. Jan 2014 A1
20140009227 Kay et al. Jan 2014 A1
20140028370 Wimpenny Jan 2014 A1
20140028392 Wimpenny Jan 2014 A1
20140049321 Gebeyehu et al. Feb 2014 A1
20140103995 Langer Apr 2014 A1
20140184335 Nobbe et al. Jul 2014 A1
Foreign Referenced Citations (35)
Number Date Country
1211355 Mar 1999 CN
1518209 Aug 2004 CN
1898860 Jan 2007 CN
101201891 Jun 2008 CN
101379695 Mar 2009 CN
101416385 Apr 2009 CN
101427459 May 2009 CN
101626355 Jan 2010 CN
101635697 Jan 2010 CN
101867284 Oct 2010 CN
0755121 Jan 1997 EP
1317105 Jun 2003 EP
1492227 Dec 2004 EP
1557955 Jul 2005 EP
1569330 Aug 2005 EP
2214304 Aug 2010 EP
2244366 Oct 2010 EP
2372904 Oct 2011 EP
2579456 Apr 2013 EP
2398648 Aug 2004 GB
2462204 Feb 2010 GB
2465552 May 2010 GB
2484475 Apr 2012 GB
461168 Oct 2001 TW
0048306 Aug 2000 WO
2004002006 Dec 2003 WO
2004082135 Sep 2004 WO
2005013084 Feb 2005 WO
2006021774 Mar 2006 WO
2006070319 Jul 2006 WO
2006073208 Jul 2006 WO
2007107919 Sep 2007 WO
2007149346 Dec 2007 WO
2012151594 Nov 2012 WO
2012172544 Dec 2012 WO
Non-Patent Literature Citations (196)
Entry
Notice of Allowance for U.S. Appl. No. 14/072,140, mailed Dec. 2, 2014, 8 pages.
First Office Action for Chinese Patent Application No. 201280026559.0, issued Nov. 3, 2014, 14 pages (with English translation).
Notice of Allowance for U.S. Appl. No. 13/486,012, mailed Nov. 21, 2014, 8 pages.
Final Office Action for U.S. Appl. No. 13/689,883, mailed Jan. 2, 2015, 13 pages.
Notice of Allowance for U.S. Appl. No. 13/690,187, mailed Dec. 19, 2014, 8 pages.
Notice of Allowance for U.S. Appl. No. 13/747,694, mailed Dec. 22, 2014, 9 pages.
Notice of Allowance for U.S. Appl. No. 13/951,976, mailed Dec. 26, 2014, 9 pages.
Non-Final Office Action for U.S. Appl. No. 13/747,749, mailed Nov. 12, 2014, 32 pages.
Notice of Allowance for U.S. Appl. No. 13/948,291, mailed Feb. 11, 2015, 7 pages.
First Office Action for Chinese Patent Application No. 201180030273.5, issued Dec. 3, 2014, 15 pages (with English translation).
Notice of Allowance for U.S. Appl. No. 14/022,858, mailed Feb. 17, 2015, 7 pages.
Notice of Allowance for U.S. Appl. No. 14/072,225, mailed Jan. 22, 2015, 7 pages.
Final Office Action for U.S. Appl. No. 13/661,227, mailed Feb. 6, 2015, 24 pages.
International Preliminary Report on Patentability for PCT/US2013/052277, mailed Feb. 5, 2015, 9 pages.
Non-Final Office Action for U.S. Appl. No. 14/048,109, mailed Feb. 18, 2015, 8 pages.
Notice of Allowance for U.S. Appl. No. 13/747,725, mailed Feb. 2, 2015, 10 pages.
Notice of Allowance for U.S. Appl. No. 12/836,307, mailed Mar. 2, 2015, 6 pages.
Notice of Allowance for U.S. Appl. No. 13/297,470, mailed Feb. 25, 2015, 15 pages.
Corrected Notice of Allowance for U.S. Appl. No. 13/297,470, mailed Apr. 6, 2015, 11 pages.
European Search Report for European Patent Application No. 14190851.7, issued Mar. 5, 2015, 6 pages.
Non-Final Office Action for U.S. Appl. No. 14/122,852, mailed Feb. 27, 2015, 5 pages.
Final Office Action for U.S. Appl. No. 13/714,600, mailed Mar. 10, 2015, 14 pages.
Non-Final Office Action for U.S. Appl. No. 14/056,292, mailed Mar. 6, 2015, 8 pages.
Final Office Action for U.S. Appl. No. 13/747,749, mailed Mar. 20, 2015, 35 pages.
Non-Final Office Action for U.S. Appl. No. 14/072,120, mailed Apr. 14, 2015, 8 pages.
Choi, J. et al., “A New Power Management IC Architecture for Envelope Tracking Power Amplifier,” IEEE Transactions on Microwave Theory and Techniques, vol. 59, No. 7, Jul. 2011, pp. 1796-1802.
Cidronali, A. et al., “A 240W dual-band 870 and 2140 MHz envelope tracking GaN PA designed by a probability distribution conscious approach,” IEEE MTT-S International Microwave Symposium Digest, Jun. 5-10, 2011, 4 pages.
Dixon, N., “Standardisation Boosts Momentum for Envelope Tracking,” Microwave Engineering, Europe, Apr. 20, 2011, 2 pages, http://www.mwee.com/en/standardisation-boosts-momentum-for-envelope-tracking.html?cmp—ids=71&news—ids=222901746.
Hassan, Muhammad, et al., “A Combined Series-Parallel Hybrid Envelope Amplifier for Envelope Tracking Mobile Terminal RF Power Amplifier Applications,” IEEE Journal of Solid-State Circuits, vol. 47, No. 5, May 2012, pp. 1185-1198.
Hekkala, A. et al., “Adaptive Time Misalignment Compensation in Envelope Tracking Amplifiers,” 2008 IEEE International Symposium on Spread Spectrum Techniques and Applications, Aug. 2008, pp. 761-765.
Hoversten, John, et al., “Codesign of PA, Supply, and Signal Processing for Linear Supply-Modulated RF Transmitters,” IEEE Transactions on Microwave Theory and Techniques, vol. 60, No. 6, Jun. 2012, pp. 2010-2020.
Kim et al., “High Efficiency and Wideband Envelope Tracking Power Amplifiers with Sweet Spot Tracking,” 2010 IEEE Radio Frequency Integrated Circuits Symposium, May 23-25, 2010, pp. 255-258.
Kim, N. et al, “Ripple Feedback Filter Suitable for Analog/Digital Mixed-Mode Audio Amplifier for Improved Efficiency and Stability,” 2002 IEEE Power Electronics Specialists Conference, vol. 1, Jun. 23, 2002, pp. 45-49.
Knutson, P, et al., “An Optimal Approach to Digital Raster Mapper Design,” 1991 IEEE International Conference on Consumer Electronics held Jun. 5-7, 1991, vol. 37, Issue 4, published Nov. 1991, pp. 746-752.
Le, Hanh-Phuc et al., “A 32nm Fully Integrated Reconfigurable Switched-Capacitor DC-DC Convertor Delivering 0.55W/mm^2 at 81% Efficiency,” 2010 IEEE International Solid State Circuits Conference, Feb. 7-11, 2010, pp. 210-212.
Li, Y. et al., “A Highly Efficient SiGe Differential Power Amplifier Using an Envelope-Tracking Technique for 3GPP LTE Applications,” 2010 IEEE Bipolar/BiCMOS Circuits and Technology Meeting (BCTM), Oct. 4-6, 2010, pp. 121-124.
Lie, Donald Y.C. et al., “Design of Highly-Efficient Wideband RF Polar Transmitters Using Envelope-Tracking (ET) for Mobile WiMAX/Wibro Applications,” IEEE 8th International Conference on ASIC (ASCION), Oct. 20-23, 2009, pp. 347-350.
Lie, Donald Y.C. et al., “Highly Efficient and Linear Class E SiGe Power Amplifier Design,” 8th International Conference on Solid-State and Integrated Circuit Technology (ICSICT), Oct. 23-26, 2006, pp. 1526-1529.
Sahu, B. et al., “Adaptive Power Management of Linear RF Power Amplifiers in Mobile Handsets—An Integrated System Design Approach,” submission for IEEE Asia Pacific Microwave Conference, Mar. 2004, 4 pages.
Unknown Author, “Nujira Files 100th Envelope Tracking Patent,” CS: Compound Semiconductor, Apr. 11, 2011, 1 page, http://www.compoundsemiconductor.net/csc/news-details.php?cat=news&id=19733338&key=Nujira%20Files%20100th%20Envelope%20Tracking%20Patent&type=n.
Wu, Patrick Y. et al., “A Two-Phase Switching Hybrid Supply Modulator for RF Power Amplifiers with 9% Efficiency Improvement,” IEEE Journal of Solid-State Circuits, vol. 45, No. 12, Dec. 2010, pp. 2543-2556.
Yousefzadeh, Vahid et al., “Band Separation and Efficiency Optimization in Linear-Assisted Switching Power Amplifiers,” 37th IEEE Power Electronics Specialists Conference, Jun. 18-22, 2006, pp. 1-7.
Non-final Office Action for U.S. Appl. No. 11/113,873, now U.S. Pat. No. 7,773,691, mailed Feb. 1, 2008, 17 pages.
Final Office Action for U.S. Appl. No. 11/113,873, now U.S. Pat. No. 7,773,691, mailed Jul. 30, 2008, 19 pages.
Non-final Office Action for U.S. Appl. No. 11/113,873, now U.S. Pat. No. 7,773,691, mailed Nov. 26, 2008, 22 pages.
Final Office Action for U.S. Appl. No. 11/113,873, now U.S. Pat. No. 7,773,691, mailed May 4, 2009, 20 pages.
Non-final Office Action for U.S. Appl. No. 11/113,873, now U.S. Pat. No. 7,773,691, mailed Feb. 3, 2010, 21 pages.
Notice of Allowance for U.S. Appl. No. 11/113,873, now U.S. Pat. No. 7,773,691, mailed Jun. 9, 2010, 7 pages.
International Search Report for PCT/US06/12619, mailed May 8, 2007, 2 pages.
Extended European Search Report for application 06740532.4, mailed Dec. 27, 2010, 7 pages.
Non-final Office Action for U.S. Appl. No. 12/112,006, mailed Apr. 5, 2010, 6 pages.
Notice of Allowance for U.S. Appl. No. 12/112,006, mailed Jul. 19, 2010, 6 pages.
Non-Final Office Action for U.S. Appl. No. No. 12/836,307, mailed Nov. 5, 2013, 6 pages.
Notice of Allowance for U.S. Appl. No. 12/836,307, mailed May 5, 2014, 6 pages.
Non-final Office Action for U.S. Appl. No. 13/089,917, mailed Nov. 23, 2012, 6 pages.
Examination Report for European Patent Application No. 11720630, mailed Aug. 16, 2013, 5 pages.
Examination Report for European Patent Application No. 11720630.0, issued Mar. 18, 2014, 4 pages.
European Search Report for European Patent Application No. 14162682.0, issued Aug. 27, 2014, 7 pages.
International Search Report for PCT/US11/033037, mailed Aug. 9, 2011, 10 pages.
International Preliminary Report on Patentability for PCT/US2011/033037, mailed Nov. 1, 2012, 7 pages.
Non-Final Office Action for U.S. Appl. No. 13/188,024, mailed Feb. 5, 2013, 8 pages.
Notice of Allowance for U.S. Appl. No. 13/188,024, mailed Jun. 18, 2013, 8 pages.
International Search Report for PCT/US2011/044857, mailed Oct. 24, 2011, 10 pages.
International Preliminary Report on Patentability for PCT/US2011/044857, mailed Mar. 7, 2013, 6 pages.
Non-final Office Action for U.S. Appl. No. 13/218,400, mailed Nov. 8, 2012, 7 pages.
Notice of Allowance for U.S. Appl. No. 13/218,400, mailed Apr. 11, 2013, 7 pages.
International Search Report for PCT/US11/49243, mailed Dec. 22, 2011, 9 pages.
International Preliminary Report on Patentability for PCT/US11/49243, mailed Nov. 13, 2012, 33 pages.
International Search Report for PCT/US2011/054106, mailed Feb. 9, 2012, 11 pages.
International Preliminary Report on Patentability for PCT/US2011/054106, mailed Apr. 11, 2013, 8 pages.
Notice of Allowance for U.S. Appl. No. 13/297,490, mailed Feb. 27, 2014, 7 pages.
Invitation to Pay Additional Fees for PCT/US2011/061007, mailed Feb. 13, 2012, 7 pages.
International Search Report for PCT/US2011/061007, mailed Aug. 16, 2012, 16 pages.
International Preliminary Report on Patentability for PCT/US2011/061007, mailed May 30, 2013, 11 pages.
Non-Final Office Action for U.S. Appl. No. 13/297,470, mailed May 8, 2013, 15 pages.
Final Office Action for U.S. Appl. No. 13/297,470, mailed Oct. 25, 2013, 17 pages.
Non-Final Office Action for U.S. Appl. No. 13/297,470, mailed Feb. 20, 2014, 16 pages.
International Search Report for PCT/US2011/061009, mailed Feb. 8, 2012, 14 pages.
International Preliminary Report on Patentability for PCT/US2011/061009, mailed May 30, 2013, 10 pages.
Notice of Allowance for U.S. Appl. No. 14/022,858, mailed Oct. 25, 2013, 9 pages.
Notice of Allowance for U.S. Appl. No. 14/022,858, mailed May 27, 2014, 6 pages.
Notice of Allowance for U.S. Appl. No. 13/343,840, mailed Jul. 1, 2013, 8 pages.
International Search Report for PCT/US2012/023495, mailed May 7, 2012, 13 pages.
International Preliminary Report on Patentability for PCT/US2012/023495, mailed Aug. 15, 2013, 10 pages.
Notice of Allowance for U.S. Appl. No. 13/363,888, mailed Jul. 18, 2013, 9 pages.
Non-final Office Action for U.S. Appl. No. 13/222,453, mailed Dec. 6, 2012, 13 pages.
Notice of Allowance for U.S. Appl. No. 13/222,453, mailed Feb. 21, 2013, 7 pages.
Notice of Allowance for U.S. Appl. No. 13/222,453, mailed Aug. 22, 2013, 8 pages.
Non-Final Office Action for U.S. Appl. No. 13/367,973, mailed Sep. 24, 2013, 8 pages.
Non-Final Office Action for U.S. Appl. No. 13/367,973, mailed Apr. 25, 2014, 5 pages.
Invitation to Pay Additional Fees and Where Applicable Protest Fee for PCT/US2012/024124, mailed Jun. 1, 2012, 7 pages.
International Search Report for PCT/US2012/024124, mailed Aug. 24, 2012, 14 pages.
International Preliminary Report on Patentability for PCT/US2012/024124, mailed Aug. 22, 2013, 8 pages.
Non-Final Office Action for U.S. Appl. No. 13/423,649, mailed May 22, 2013, 7 pages.
Notice of Allowance for U.S. Appl. No. 13/423,649, mailed Aug. 30, 2013, 8 pages.
Notice of Allowance for U.S. Appl. No. 14/072,140, mailed Aug. 27, 2014, 8 pages.
Notice of Allowance for U.S. Appl. No. 13/316,229, mailed Nov. 14, 2012, 9 pages.
Notice of Allowance for U.S. Appl. No. 13/316,229, mailed Aug. 29, 2013, 8 pages.
International Search Report for PCT/US2011/064255, mailed Apr. 3, 2012, 12 pages.
International Preliminary Report on Patentability for PCT/US2011/064255, mailed Jun. 20, 2013, 7 pages.
Non-Final Office Action for U.S. Appl. No. 14/072,225, mailed Aug. 15, 2014, 4 pages.
International Search Report for PCT/US2012/40317, mailed Sep. 7, 2012, 7 pages.
International Preliminary Report on Patentability for PCT/US2012/040317, mailed Dec. 12, 2013, 5 pages.
Non-Final Office Action for U.S. Appl. No. 13/486,012, mailed Jul. 28, 2014, 7 pages.
Quayle Action for U.S. Appl. No. 13/531,719, mailed Oct. 10, 2013, 5 pages.
Notice of Allowance for U.S. Appl. No. 13/531,719, mailed Dec. 30, 2013, 7 pages.
Notice of Allowance for U.S. Appl. No. 13/548,283, mailed Sep. 3, 2014, 7 pages.
Non-Final Office Action for U.S. Appl. No. 13/550,049, mailed Nov. 25, 2013, 6 pages.
Notice of Allowance for U.S. Appl. No. 13/550,049, mailed Mar. 6, 2014, 5 pages.
International Search Report for PCT/US2012/046887, mailed Dec. 21, 2012, 12 pages.
International Preliminary Report on Patentability for PCT/US2012/046887, mailed Jan. 30, 2014, 8 pages.
Notice of Allowance for U.S. Appl. No. 13/550,060, mailed Aug. 16, 2013, 8 pages.
Non-final Office Action for U.S. Appl. No. 13/222,484, mailed Nov. 8, 2012, 9 pages.
Final Office Action for U.S. Appl. No. 13/222,484, mailed Apr. 10, 2013, 10 pages.
Advisory Action for U.S. Appl. No. 13/222,484, mailed Jun. 14, 2013, 3 pages.
Notice of Allowance for U.S. Appl. No. 13/222,484, mailed Aug. 26, 2013, 8 pages.
Notice of Allowance for U.S. Appl. No. 13/602,856, mailed Sep. 24, 2013, 9 pages.
International Search Report and Written Opinion for PCT/US2012/053654, mailed Feb. 15, 2013, 11 pages.
International Preliminary Report on Patentability for PCT/US2012/053654, mailed Mar. 13, 2014, 7 pages.
Non-Final Office Action for U.S. Appl. No. 13/647,815, mailed May 2, 2014, 6 pages.
Non-Final Office Action for U.S. Appl. No. 13/689,883, mailed Mar. 27, 2014, 13 pages.
Non-Final Office Action for U.S. Appl. No. 13/689,883, mailed Aug. 27, 2014, 12 pages.
International Search Report and Written Opinion for PCT/US2012/062070, mailed Jan. 21, 2013, 12 pages.
International Preliminary Report on Patentability for PCT/US2012/062070, mailed May 8, 2014, 8 pages.
Non-Final Office Action for U.S. Appl. No. 13/661,552, mailed Feb. 21, 2014, 5 pages.
Notice of Allowance for U.S. Appl. No. 13/661,552, mailed Jun. 13, 2014, 5 pages.
International Search Report and Written Opinion for PCT/US2012/062110, issued Apr. 8, 2014, 12 pages.
International Preliminary Report on Patentability for PCT/US2012/062110, mailed May 8, 2014, 9 pages.
Non-Final Office Action for U.S. Appl. No. 13/692,084, mailed Apr. 10, 2014, 6 pages.
Notice of Allowance for U.S. Appl. No. 13/692,084, mailed Jul. 23, 2014, 7 pages.
Notice of Allowance for U.S. Appl. No. 13/690,187, mailed Sep. 3, 2014, 9 pages.
International Search Report and Written Opinion for PCT/US2012/067230, mailed Feb. 21, 2013, 10 pages.
International Preliminary Report on Patentability and Written Opinion for PCT/US2012/067230, mailed Jun. 12, 2014, 7 pages.
Non-Final Office Action for U.S. Appl. No. 13/684,826, mailed Apr. 3, 2014, 5 pages.
Notice of Allowance for U.S. Appl. No. 13/684,826, mailed Jul. 18, 2014, 7 pages.
Non-Final Office Action for U.S. Appl. No. 14/022,940, mailed Dec. 20, 2013, 5 pages.
Notice of Allowance for U.S. Appl. No. 14/022,940, mailed Jun. 10, 2014, 7 pages.
Non-Final Office Action for U.S. Appl. No. 13/714,600, mailed May 9, 2014, 14 pages.
Non-Final Office Action for U.S. Appl. No. 13/782,142, mailed Sep. 4, 2014, 6 pages.
Non-Final Office Action for U.S. Appl. No. 13/951,976, mailed Apr. 4, 2014, 7 pages.
International Search Report and Written Opinion for PCT/US2013/052277, mailed Jan. 7, 2014, 14 pages.
International Search Report and Written Opinion for PCT/US2013/065403, mailed Feb. 5, 2014, 11 pages.
International Search Report and Written Opinion for PCT/US2014/028089, mailed Jul. 17, 2014, 10 pages.
Invitation to Pay Additional Fees and Partial International Search Report for PCT/US2014/028178, mailed Jul. 24, 2014, 7 pages.
Non-Final Office Action for U.S. Appl. No. 12/836,307, mailed Sep. 25, 2014, 5 pages.
Advisory Action for U.S. Appl. No. 13/297,470, mailed Sep. 19, 2014, 3 pages.
Non-Final Office Action for U.S. Appl. No. 13/297,470, mailed Oct. 20, 2014, 22 pages.
Notice of Allowance for U.S. Appl. No. 13/367,973, mailed Sep. 15, 2014, 7 pages.
Extended European Search Report for European Patent Application No. 12794149.0, issued Oct. 29, 2014, 6 pages.
Notice of Allowance for U.S. Appl. No. 13/647,815, mailed Sep. 19, 2014, 6 pages.
Non-Final Office Action for U.S. Appl. No. 13/661,227, mailed Sep. 29, 2014, 24 pages.
Notice of Allowance for U.S. Appl. No. 13/684,826, mailed Sep. 8, 2014, 6 pages.
Non-Final Office Action for U.S. Appl. No. 13/714,600, mailed Oct. 15, 2014, 13 pages.
Notice of Allowance for U.S. Appl. No. 13/914,888, mailed Oct. 17, 2014, 10 pages.
Non-Final Office Action for U.S. Appl. No. 13/747,725, mailed Oct. 7, 2014, 6 pages.
International Search Report and Written Opinion for PCT/US2014/012927, mailed Sep. 30, 2014, 11 pages.
International Search Report and Written Opinion for PCT/US2014/028178, mailed Sep. 30, 2014, 17 pages.
Corrected Notice of Allowance for U.S. Appl. No. 13/297,470, mailed Jun. 5, 2015, 11 pages.
Advisory Action for U.S. Appl. No. 13/661,227, mailed May 12, 2015, 3 pages.
Advisory Action for U.S. Appl. No. 13/714,600, mailed May 26, 2015, 3 pages.
Notice of Allowance for U.S. Appl. No. 13/747,725, mailed May 13, 2015, 9 pages.
Notice of Allowance for U.S. Appl. No. 13/747,749, mailed Jun. 4, 2015, 8 pages.
Non-Final Office Action for U.S. Appl. No. 14/163,229, mailed Apr. 23, 2015, 9 pages.
Non-Final Office Action for U.S. Appl. No. 14/163,256, mailed Apr. 23, 2015, 9 pages.
Notice of Allowance for U.S. Appl. No. 14/176,611, mailed Apr. 27, 2015, 7 pages.
Quayle Action for U.S. Appl. No. 13/689,940, mailed May 14, 2015, 7 pages.
Notice of Allowance for U.S. Appl. No. 13/661,164, mailed Jun. 3, 2015, 6 pages.
Non-Final Office Action for U.S. Appl. No. 14/082,629, mailed Jun. 18, 2015, 15 pages.
European Examination Report for European Patent Application No. 14162682.0, mailed May 22, 2015, 5 pages.
International Preliminary Report on Patentability for PCT/US2013/065403, mailed Apr. 30, 2015, 8 pages.
First Office Action and Search Report for Chinese Patent Application No. 201280007941.7, issued May 13, 2015, 13 pages.
Yun, Hu et al., “Study of envelope tracking power amplifier design,” Journal of Circuits and Systems, vol. 15, No. 6, Dec. 2010, pp. 6-10.
Notice of Allowance for U.S. Appl. No. 13/948,291, mailed Jul. 17, 2015, 8 pages.
Non-Final Office Action for U.S. Appl. No. 13/689,883, mailed Jul. 24, 2015, 13 pages.
Non-Final Office Action for U.S. Appl. No. 13/661,227, mailed Jul. 27, 2015, 25 pages.
Non-Final Office Action for U.S. Appl. No. 13/714,600, mailed Jul. 17, 2015, 14 pages.
Notice of Allowance for U.S. Appl. No. 14/212,199, mailed Jul. 20, 2015, 8 pages.
Notice of Allowance for U.S. Appl. No. 14/072,120, mailed Jul. 30, 2015, 7 pages.
Notice of Allowance for U.S. Appl. No. 13/689,940, mailed Aug. 3, 2015, 6 pages.
Notice of Allowance for U.S. Appl. No. 14/072,140, mailed Aug. 20, 2015, 6 pages.
Non-Final Office Action for U.S. Appl. No. 14/072,225, mailed Aug. 18, 2015, 4 pages.
Notice of Allowance for U.S. Appl. No. 13/747,725, mailed Sep. 1, 2015, 9 pages.
Notice of Allowance for U.S. Appl. No. 14/027,416, mailed Aug. 11, 2015, 9 pages.
International Preliminary Report on Patentability for PCT/US2014/012927, mailed Aug. 6, 2015, 9 pages.
First Office Action and Search Report for Chinese Patent Application No. 201210596632.X, mailed Jun. 25, 2015, 16 pages.
Notice of Allowance for U.S. Appl. No. 13/747,749, mailed Oct. 2, 2015, 8 pages.
Notice of Allowance for U.S. Appl. No. 13/552,768, mailed Sep. 22, 2015, 9 pages.
Final Office Action for U.S. Appl. No. 13/689,922, mailed Oct. 6, 2015, 20 pages.
Notice of Allowance for U.S. Appl. No. 13/727,911, mailed Sep. 14, 2015, 8 pages.
Notice of Allowance for U.S. Appl. No. 13/689,940, mailed Sep. 16, 2015, 7 pages.
Non-Final Office Action for U.S. Appl. No. 14/101,770, mailed Sep. 21, 2015, 5 pages.
Non-Final Office Action for U.S. Appl. No. 14/702,192, mailed Oct. 7, 2015, 7 pages.
Non-Final Office Action for U.S. Appl. No. 14/254,215, mailed Oct. 15, 2015, 5 pages.
Second Office Action for Chinese Patent Application No. 201180030273.5, issued Aug. 14, 2015, 8 pages.
International Preliminary Report on Patentability for PCT/US2014/028089, mailed Sep. 24, 2015, 8 pages.
International Preliminary Report on Patentability for PCT/US2014/028178, mailed Sep. 24, 2015, 11 pages.
Related Publications (1)
Number Date Country
20140266427 A1 Sep 2014 US
Provisional Applications (1)
Number Date Country
61783897 Mar 2013 US