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`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________________________________________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________________________________________
`
`Intel Corporation
`Petitioner
`
`v.
`
`Qualcomm Incorporated
`Patent Owner
`
`U.S. Patent No. 8,698,558
`Claims 12-14
`____________________________________________
`
`Case IPR2018-01152
`____________________________________________
`
`DECLARATION OF ALYSSA APSEL, PH.D.
`ON BEHALF OF PETITIONER
`
`
`
`
`INTEL 1003
`
`

`

`TABLE OF CONTENTS
`BACKGROUND ............................................................................................. 1 
`I. 
`II.  MATERIALS CONSIDERED ........................................................................ 4 
`III.  LEGAL PRINCIPLES ..................................................................................... 6 
`A. 
`Claim Construction ............................................................................... 6 
`B. 
`Anticipation ........................................................................................... 7 
`C. 
`Obviousness ........................................................................................... 8 
`IV.  SUMMARY OF OPINIONS ......................................................................... 10 
`V. 
`BRIEF DESCRIPTION OF THE TECHNOLOGY ..................................... 11 
`A. 
`Radio Frequency (RF) Power Amplifiers ........................................... 11 
`B. 
`Power Supply Generators/Modulators for Power Amplifiers ............. 12 
`Envelope Amplifiers ................................................................. 13 
` 
`Switchers ................................................................................... 15 
` 
`Hybrid Supply Generators ........................................................ 16 
` 
`Boost Converters ....................................................................... 20 
` 
`C.  Multiplexers ......................................................................................... 22 
`VI.  OVERVIEW OF THE ’558 PATENT .......................................................... 24 
`A. 
`Summary of the Alleged Invention of the ’558 Patent ....................... 24 
`B. 
`Prosecution History ............................................................................. 30 
`VII.  OVERVIEW OF THE PRIOR ART REFERENCES ................................... 32 
`A. 
`Chu ...................................................................................................... 32 
`B. 
`Choi 2010 ............................................................................................ 37 
`VIII.  CLAIM CONSTRUCTION .......................................................................... 39 
`A. 
`“current sense amplifier” (claim 12) ................................................... 39 
`B. 
`“envelope signal” (claim 12) ............................................................... 41 
`IX.  LEVEL OF ORDINARY SKILL IN THE ART ........................................... 41 
`X. 
`SPECIFIC GROUNDS FOR CHALLENGE ................................................ 42 
`A.  Ground I: Claims 12 and 14 are anticipated by Chu .......................... 42 
`Claim 12 .................................................................................... 42 
` 
`Claim 14 .................................................................................... 60 
` 
`
`i
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`

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`B. 
`
`C. 
`
`Ground II: Claim 14 is obvious over Chu combined with
`Blanken ................................................................................................ 71 
`Claim 14 .................................................................................... 71 
` 
`Ground III: Claim is obvious over Chu combined with Choi
`2010 ..................................................................................................... 76 
`Claim 13 .................................................................................... 76 
` 
`D.  Ground IV: Claim 13 is obvious over Chu combined with Choi
`2010 and Myers ................................................................................... 88 
`Claim 13 .................................................................................... 88 
` 
`XI.  AVAILABILITY FOR CROSS-EXAMINATION .................................... 101 
`XII.  RIGHT TO SUPPLEMENT ........................................................................ 101 
`XIII.  JURAT ......................................................................................................... 101 
`
`
`ii
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`

`

`I, Alyssa Apsel, declare as follows:
`
`I.
`
`BACKGROUND
`1.
`I am currently a professor of electrical and computer engineering at
`
`Cornell University in Ithaca, New York, and a visiting professor at Imperial
`
`College in London, England.
`
`2.
`
`I have also been the Chief Technology Officer for AlphaWave IP
`
`Corporation, a multinational private equity-backed company that provides high-
`
`end analog silicon IP related to high-end Multi Standard SerDes (MSS) and Multi
`
`Standard Radio (MSR) solutions for a wide range of markets.
`
`3. My qualifications are stated more fully in my curriculum vitae, which
`
`is attached as Appendix A. I briefly summarize my education, work experience,
`
`and other qualifications below.
`
`4.
`
`I received a Bachelor of Science degree in Electrical Engineering
`
`from Swarthmore College in 1995. I then earned a Master of Science degree in
`
`Electrical Engineering from the California Institute of Technology in 1996. I
`
`received my Ph.D. in Electrical Engineering from the Johns Hopkins University in
`
`2002, where the focus of my program was electrical and computer engineering.
`
`My doctoral studies included analog and mixed signal circuit design for
`
`optoelectronic and highspeed communication systems. My dissertation, titled
`
`“Optoelectronic Receivers in Silicon on Sapphire CMOS: Architecture and Design
`
`1
`
`

`

`for Efficient Parallel Interconnects,” included the study of integrated interface
`
`circuits for high-speed chip-to-chip communications.
`
`5.
`
`By 2000, I had completed all of my coursework at Johns Hopkins,
`
`including approximately 2-3 years of graduate courses in circuits and devices,
`
`passed the Ph.D. Comprehensive Exam (required to advance in the Ph.D. program
`
`and equivalent of a Master Degree), completed significant independent research on
`
`optical receiver circuits in CMOS, and published six conference papers.
`
`6.
`
`By 2002, I had completed my Ph.D. at Johns Hopkins, published 3
`
`journal papers, 10 conference papers, and had 5 years of experience in wireless
`
`communications that included working at the Army Research Laboratory.
`
`7.
`
`I was a consultant for Intel Research from January 2009 to June 2009.
`
`In that role, I developed process invariant calibration blocks for high speed I/O
`
`circuits. These circuits were designed to monitor and maintain good operating
`
`conditions, despite imperfections and flaws in the manufacturing process, of the
`
`high-speed receivers and transmitters that enable computers to send and receive
`
`data over long wires.
`
`8.
`
`From June 2008 to October 2015, I was an Associate Professor of
`
`Electrical and Computer Engineering at Cornell University. During that time, I
`
`worked on research regarding low-power radio design and networking, systems
`
`and circuit co-design for efficient low power networks, design in presence of
`
`2
`
`

`

`process variation, and high-speed radio frequency (RF) systems. From June 2014
`
`to June 2016, I was the Director of Graduate Studies at Cornell University. In that
`
`role, I directed the graduate program, oversaw admissions to the graduate program,
`
`and was a Chair on the Graduate Committee, among other responsibilities.
`
`9.
`
`In November 2015, I became a full professor of Electrical and
`
`Computer Engineering at Cornell University. My primary research interests
`
`include disruptive RF design, software defined radio, ultra-low power RF
`
`networks, and the Internet of Things (IoT).
`
`10. Starting in September 2016 to present, I have been a visiting professor
`
`at Imperial College in London. I am currently working on low-power RF
`
`interfaces for implantable electronics.
`
`11. From 2014 to 2016, I served on the Board of Governors of the
`
`Institute of Electrical and Electronics Engineers (“IEEE”) Circuits and Systems
`
`Society.
`
`12. From January 2016 to December 2017, I was the Senior Editor of the
`
`IEEE Journal on Emerging and Selected Topics in Circuits and Systems. During
`
`that time, I was also the Deputy Editor in Chief of IEEE Circuits and Systems
`
`Magazine.
`
`13.
`
`I have published numerous books, book chapters, and articles in the
`
`field of electrical engineering design. My publications are listed in Appendix A.
`
`3
`
`

`

`14.
`
`I have given several lectures and seminars regarding electrical
`
`engineering design and radio networks. A list of these lectures and seminars can
`
`be found in my curriculum vitae at Appendix A. I am currently a Distinguished
`
`Lecturer of the IEEE Circuits and Systems Society.
`
`15.
`
`I have been retained by the Petitioner Intel Corporation as an expert in
`
`the field of power circuitry for radio frequency devices. I am working as an
`
`independent consultant in this matter and am being compensated at my standard
`
`hourly consulting rate of $550. My compensation is not dependent on the outcome
`
`of these proceedings or the content of my opinions.
`
`16.
`
`I have no financial interest in the Petitioner. I similarly have no
`
`financial interest in the ’558 patent and have had no contact with the named
`
`inventors of the ’558 patent.
`
`II. MATERIALS CONSIDERED
`17.
`I have reviewed the specification, claims, and file history of U.S.
`
`Patent No. 8,698,558 (“’558 patent”) (Ex. 1001). I understand that the ’558 patent
`
`was filed on June 23, 2011 and issued on April 15, 2104 from U.S. Patent
`
`Application No. 13/167,659.
`
`18.
`
`I have reviewed the following publications and related declarations in
`
`preparing this declaration:
`
`4
`
`

`

` Chu, W.Y. et al., “A 10 MHz bandwidth, 2 mV ripple PA regulator for
`
`CDMA transmitters,” IEEE Journal of Solid-State Circuits 2809-2819
`
`(2008) (“Chu”) (Ex. 1004). Chu was published in 2008. Ex. 1005 at
`
`¶14.
`
` Choi, J. et al., “Envelope tracking power amplifier robust to battery
`
`depletion,” Microwave Symposium Digest (MTT), 2010 IEEE MTT-S
`
`International (“Choi 2010”) (Ex. 1006). Based on my review of the
`
`declarations submitted with this petition, I understand that Choi 2010 has
`
`been available from the IEEE Xplore website at
`
`http://ieeexplore.ieee.org/abstract/document/5517825/ since July 23,
`
`2010. Ex. 1007 at ¶11. I also understand from the declarations that Choi
`
`2010 was presented in May 2010 at a leading technical conference of
`
`skilled artisans, the IEEE International Microwave Symposium (“IMS”)
`
`2010 conference, in Anaheim, California, and that Choi 2010 was
`
`distributed to hundreds of conference attendees via USB drives in May
`
`2010. Ex. 1008 at ¶17; Ex. 1006 at cover; Ex. 1009 at ¶¶4-9.
`
` Blanken, P.G. et al., “A 50MHz bandwidth multi-mode PA supply
`
`modulator for GSM, EDGE and UMTS application,” 2008 Radio
`
`Frequency Integrated Circuits Symposium (IEEE) (“Blanken”) (Ex.
`
`5
`
`

`

`1010). According to the declaration submitted by the IEEE, Blanken was
`
`published in 2008. Ex. 1005 at ¶12.
`
` U.S. Patent No. 5,929,702, “Method and Apparatus for High Efficiency
`
`High Dynamic Range Power Amplification,” to Myers et al. (“Myers”)
`
`(Ex. 1012). Myers was filed on November 28, 1997 and issued on July
`
`27, 1999.
`
`19.
`
`I have reviewed the above patent, patent publications, and all other
`
`publications cited in this declaration. I have considered the invalidity issues from
`
`the perspective of a person of ordinary skill in the art as described below at the
`
`time the ’558 patent application was filed.
`
`III. LEGAL PRINCIPLES
`20.
`I am not an attorney. For the purposes of this declaration, I have been
`
`informed about certain aspects of the law that are relevant to my opinions. My
`
`understanding of the law is as follows:
`
`A. Claim Construction
`21.
`I have been informed that claim construction is a matter of law and
`
`that the final claim construction will ultimately be determined by the Board. For
`
`the purposes of my analysis in this proceeding and with respect to the prior art, I
`
`have been informed that patents are currently reviewed in an inter partes review
`
`(IPR) proceeding under the “broadest reasonable interpretation” standard
`
`6
`
`

`

`(hereinafter “BRI standard”). I also have been informed that IPRs may soon be
`
`reviewed under what is known as “the Phillips standard.”
`
`22.
`
`I have been informed that the BRI standard refers to the broadest
`
`reasonable interpretation that a person of ordinary skill in the art would give to a
`
`claim term in light of the specification.
`
`23.
`
`I have been informed that under the Phillips standard, claim terms are
`
`generally given their plain and ordinary meaning as understood by a person of
`
`ordinary skill in the art at the time of the invention, with the claim term read not
`
`only in the context of the particular claim in which the disputed term appears, but
`
`also in the context of the entire patent, including the specification.
`
`24.
`
`I have been informed that the patentee can serve as his or her own
`
`lexicographer. As such, if a claim term is provided with a specific definition in the
`
`specification, that claim term should be interpreted in light of the particular
`
`definition provided by the patentee.
`
`B. Anticipation
`25.
`I have been informed and understand that a patent claim is invalid if it
`
`is “anticipated” by prior art. For the claim to be invalid because it is anticipated,
`
`all of its requirements must have existed in a single device or method that predates
`
`the claimed invention, or must have been described in a single publication or
`
`patent that predates the claimed invention. A patent claim may be “anticipated” if
`
`7
`
`

`

`each element of that claim is present either explicitly, implicitly, or inherently in a
`
`single prior art reference. I have also been informed that, to be an inherent
`
`disclosure, the prior art reference must necessarily disclose the limitation, and the
`
`fact that the reference might possibly practice or contain a claimed limitation is
`
`insufficient to establish that the reference inherently teaches the limitation.
`
`C. Obviousness
`26.
`I have been informed and understand that a patent claim is invalid if
`
`the claimed invention would have been obvious to a person of ordinary skill in the
`
`art at the time the application was filed. This means that, even if all of the
`
`requirements of a claim are not found in a single prior art reference, the claim is
`
`not patentable if the differences between the subject matter in the prior art and the
`
`subject matter in the claim would have been obvious to a person of ordinary skill in
`
`the art at the time the application was filed.
`
`27.
`
`I have been informed and understand that a determination of whether
`
`a claim would have been obvious should be based upon several factors, including,
`
`among others:
`
`
`
`
`
`the level of ordinary skill in the art at the time the application
`
`was filed;
`
`the scope and content of the prior art; and
`
`8
`
`

`

`
`
`what differences, if any, existed between the claimed invention
`
`and the prior art.
`
`28.
`
`I have been informed and understand that the teachings of two or
`
`more references may be combined in the same way as disclosed in the claims, if
`
`such a combination would have been obvious to one having ordinary skill in the
`
`art. In determining whether a combination based on either a single reference or
`
`multiple references would have been obvious, it is appropriate to consider, among
`
`other factors:
`
`
`
`whether the teachings of the prior art references disclose known
`
`concepts combined in familiar ways, which, when combined,
`
`would yield predictable results;
`
`
`
`
`
`whether a person of ordinary skill in the art could implement a
`
`predictable variation, and would see the benefit of doing so;
`
`whether the claimed elements represent one of a limited number
`
`of known design choices, and would have a reasonable
`
`expectation of success by those skilled in the art;
`
`
`
`whether a person of ordinary skill would have recognized a
`
`reason to combine known elements in the manner described in
`
`the claim;
`
`9
`
`

`

`
`
`whether there is some teaching or suggestion in the prior art to
`
`make the modification or combination of elements claimed in
`
`the patent; and
`
`
`
`whether the innovation applies a known technique that had been
`
`used to improve a similar device or method in a similar way.
`
`29.
`
`I understand that one of ordinary skill in the art has ordinary creativity
`
`and is not an automaton.
`
`30.
`
`I understand that in considering obviousness, it is important not to
`
`determine obviousness using the benefit of hindsight derived from the patent being
`
`considered.
`
`31.
`
`I have been informed and understand that a single reference can alone
`
`render a patent claim obvious, if any differences between that reference and the
`
`claims would have been obvious to a person of ordinary skill in the art at the time
`
`of the alleged invention—that is, if the person of ordinary skill could readily adapt
`
`the reference to meet the claims of the patent, by applying known concepts to
`
`achieve expected results in the adaptation of the reference.
`
`IV. SUMMARY OF OPINIONS
`32.
`It is my opinion that every limitation of claims 12-14 of the ’558
`
`patent is disclosed by the prior art, and that claims 12-14 are anticipated and/or
`
`rendered obvious by the prior art cited in this declaration.
`
`10
`
`

`

`V. BRIEF DESCRIPTION OF THE TECHNOLOGY
`33. The apparatus described in the ’558 patent contains several well-
`
`known components, including power amplifiers, envelope amplifiers, switchers,
`
`and boost converters. In this section, I provide a brief introduction to power
`
`amplifiers for use in RF transmissions and highlight a few of the known
`
`components that work with power amplifiers.
`
`A. Radio Frequency (RF) Power Amplifiers
`34. Mobile devices such as cell phones exchange phone calls and text
`
`messages with each other, and exchange data with the Internet. This information
`
`must first be sent to or received by a base station, which is a hub at the center of a
`
`cell in a wireless network that connects the mobile device to other devices and a
`
`wider network that includes the Internet. The information is transmitted between
`
`the mobile device and the base station using radio frequency (“RF”) signals.
`
`35. An RF signal carrying information to be transmitted must have
`
`enough power to ensure that it reaches the destination (the base station or the
`
`mobile device); the greater the distance between the device and the base station,
`
`the more power is needed to successfully transmit the signal. To help ensure that a
`
`signal has sufficient power, mobile devices and base stations contain a component
`
`known as a “power amplifier” (or “PA”). A PA increases the power of RF signals
`
`to a level sufficient to reach the base station or mobile device. Typically, the
`
`11
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`

`

`further the device moves from a base station, the more power amplification is
`
`needed to ensure successful transmission of the RF signal.
`
`36.
`
`In operation, a PA receives a signal (such as the signal that carries
`
`voice data for a cell phone call) as an input and, ideally, produces another RF
`
`signal as an output that is an exact replica of the input signal, but with
`
`proportionally greater power sufficient to ensure the signal reaches the destination.
`
`This proportional relationship is shown in the figure below:
`
`
`
`In other words, the PA “amplifies” the signal into a higher-power signal.
`
`B.
`Power Supply Generators/Modulators for Power Amplifiers
`37. A power amplifier itself needs power to operate: it must receive
`
`power sufficient to amplify the input signal and thereby ensure a successful
`
`transmission.
`
`38. A PA typically is powered by a voltage (called a “supply voltage”)
`
`from a power supply generator/modulator. A typical prior-art supply
`
`12
`
`

`

`generator/modulator is shown below in Figure 1(b) from the prior-art Kim
`
`reference:
`
`
`
`Kim – Figure 1(b)
`
`Kim, D. et al., “High efficiency and wideband envelope tracking power amplifier
`
`with sweet spot tracking,” Radio Frequency Integrated Circuits Symposium (RFIC)
`
`255-258 (2010) at 255 (“Kim”) (Ex. 1113). The PA shown in the bottom triangle
`
`receives a supply voltage (labeled “Modulated Supply”) that has been generated by
`
`the Supply Modulator. In this case, the supply voltage provides the PA with the
`
`amount of power needed to sufficiently amplify the input signal (“RF_IN”) and
`
`generate the amplified output signal (“RF_OUT”), without degrading the quality of
`
`the signal or wasting power through resistive losses. The amount of power
`
`required at the PA depends on the RF signal that must be transmitted.
`
`
`
`Envelope Amplifiers
`
`13
`
`

`

`39. The component shown as the top triangle in the above figure from
`
`Kim is an “envelope amplifier.” An envelope amplifier—also sometimes referred
`
`to as a “linear amplifier” or in the figure above, a “supply modulator”—is one type
`
`of power supply generator that generates power for a PA. As shown in the
`
`diagram from Kim above, the envelope amplifier (the “Supply Modulator”)
`
`receives an “envelope” signal, which is a signal that tracks the boundaries of the
`
`RF signal to be transmitted.
`
`40.
`
`In the diagram below, the RF signal is shown in black, and the blue
`
`envelope signal follows the outermost points of the oscillating RF signal:
`
`
`
`An envelope amplifier (such as the Supply Modulator in Kim) generates a supply
`
`voltage (Modulated Supply) that increases and decreases as the amplitude of the
`
`envelope signal increases and decreases. Ideally, the power provided to the PA
`
`will match the envelope signal as closely as possible, thereby providing only as
`
`much power to the PA as is necessary to transmit the RF signal.
`
`14
`
`

`

`41. Envelope amplifiers have advantages and disadvantages. They have a
`
`simple circuit configuration and can generate output signals that are accurate
`
`copies of the input signals, even when the input changes rapidly (i.e., when the RF
`
`signal has a high bandwidth), and they do not generate significant noise that could
`
`affect other circuits. But envelope amplifiers are also energy inefficient and
`
`generate considerable heat. To generate a voltage for the PA, an envelope
`
`amplifier requires its own input supply voltage. An envelope amplifier is a type of
`
`“linear regulator,” which is a device that takes an input supply voltage and reduces
`
`(or “steps-down”) that voltage as necessary to generate the output supply voltage
`
`for the PA. During this process, the power difference between the input and output
`
`voltages is dissipated in the form of heat. That necessarily means that the envelope
`
`amplifier is inefficient and will consume more power than desired.
`
`
`Switchers
`42. A “switcher,” also sometimes referred to as a “switching regulator” or
`
`“switching amplifier,” can also be used to supply power to the PA. A switcher
`
`receives energy from an input voltage source (such as a battery) and stores small
`
`amounts of that energy in storage elements such as inductors. A switcher does this
`
`by alternately connecting and disconnecting the input supply voltage (e.g., the
`
`battery of the mobile device) to the energy-storage element. When the switcher
`
`connects the input supply voltage to the energy storage element, energy is added to
`
`15
`
`

`

`the storage element. The energy can then be released from the storage element in a
`
`steady flow of current. By controlling the timing of these alternating connections /
`
`disconnections and storing up the required energy in the storage element, a
`
`switcher can supply energy to a PA without dissipating voltage as heat, like an
`
`envelope amplifier does.
`
`43. The energy losses involved in moving small amounts of energy
`
`around in this way are relatively small, and switchers are generally more efficient
`
`than envelope amplifiers for this reason. But switchers have at least one
`
`disadvantage: they can turn on and off only so fast, which means they a have
`
`lower operating bandwidth than envelope amplifiers (i.e., they are less able to
`
`supply power for an input signal that changes rapidly).
`
` Hybrid Supply Generators
`44. One well-known way to take advantage of the benefits of both
`
`envelope amplifiers and switchers is the hybrid supply generator, which combines
`
`them into a single regulator. In a hybrid supply generator, either the envelope
`
`amplifier or the switcher can supply the power to a power amplifier at a given
`
`time. This combination can provide the high frequency response of an envelope
`
`amplifier, and the high efficiency of a switcher.
`
`45. One example of a hybrid supply generators is found in U.S. Patent
`
`No. 6,300,826, which was filed by the lead inventor of the ’558 patent eleven years
`
`16
`
`

`

`before the ’558 patent application was filed. See Ex. 1014 at cover (“Mathe ’826”)
`
`(filed May 5, 2000). Mathe ’826 combines a linear amplifier with a synchronous
`
`buck DC/DC converter, which is a type of switcher. Id. As shown below, circuit
`
`110 in Mathe ’826 is a buffer amplifier circuit that includes “an AB-type RF
`
`amplifier 122 [envelope amplifier highlighted in purple], which is a moderately
`
`power efficient device having high bandwidth capabilities, and a synchronous buck
`
`DC/DC converter 124 [switcher highlighted in yellow], which is a highly efficient
`
`device having low bandwidth capabilities”:
`
`Mathe ’826 – Figure 6
`
`
`
`Ex. 1014 at Fig. 6.
`
`17
`
`

`

`46. Another example of a hybrid supply generator is discussed in a paper
`
`by Ertl from 1997 titled “Basic considerations and topologies of switched-mode
`
`assisted linear power amplifiers.” Ertl et al., IEEE Transactions on industrial
`
`electronics, Vol. 44, No. 1 at 116-123 (1997) (“Ertl”) (Ex. 1116). Ertl discloses “a
`
`combined power amplifier system” consisting of an envelope amplifier (“linear
`
`amplifier unit”) and a switcher (“a switched-mode (class D) current dumping
`
`stage”), as shown in Figure 2 below:
`
`Ertl – Figure 2
`
`
`
`Ex. 1016 at 117. Ertl describes this combination as the best of both worlds: “the
`
`fundamental drawback of conventional linear power amplifiers—the high loss—is
`
`avoided;” and “[c]ompared to a pure class D (switching) amplifier, the presented
`
`system needs no output filter to reduce the switching frequency harmonics.” Id. at
`
`116.
`
`18
`
`

`

`47. Blanken discloses yet another example. Blanken proposes a hybrid
`
`supply modulator for a PA that combines “a high-bandwidth class-AB linear
`
`regulator [envelope amplifier] with an efficient DC/DC converter [switcher] in a
`
`master-slave configuration.” Ex. 1010 at 401. Blanken discloses that:
`
`[h]igh-efficiency voltage conversion can be obtained with a switched-
`mode inductive DC/DC buck converter, but its bandwidth is limited
`due to practical limits to the switching frequency. Alternatively,
`linear regulators enable higher bandwidth at the cost of efficiency. As
`a good compromise between efficiency and bandwidth, hybrid supply
`modulators have been proposed combining a switched-mode DC/DC
`converter in parallel to a linear regulator.
`
`
`Id.; see also id. (“The supply-modulator topology is shown in Fig. 1. It contains a
`
`linear regulator and a DC/DC converter in master-slave configuration. The linear
`
`regulator is formed by a Miller-compensated two-stage amplifier built with class-A
`
`input transconductor gin and class-AB output transconductor go. . . . [T]he DC/DC
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`converter supplies the DC and low-frequency part of the load current, and the
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`linear regulator supplies the high-frequency part.”).
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`48. A 2010 paper by Kang is one more example of a known hybrid supply
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`generator. Kang discloses “a highly efficient supply modulator” that combines an
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`envelope amplifier with a switcher. Kang, D. et al., “A multimode/multiband
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`power amplifier with a boosted supply modulator,” IEEE Transactions on
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`Microwave Theory and Techniques, Vol. 58, No. 10 (2010) at 2598-2608 (“Kang”)
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`(Ex. 1017). Kang acknowledges the “low efficiency” of linear (envelope)
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`amplifiers and “the limited BW [bandwidth] of switching amplifiers [switchers].”
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`Id. at 2599. Kang explains that hybrid systems are “suitable for the envelope
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`signal of modern wireless communication systems, which has the most power in
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`the low-frequency region.” Id. at 2599. Kang proposes “a hybrid switching
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`amplifier (HSA) for multistandard applications,” and the HSA includes an
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`envelope amplifier (“linear stage”), a switcher (“switching stage”) and a boost
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`converter (discussed in the next section), as shown in Figure 4 below:
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`Kang – Figure 4
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`
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`Ex. 1017 at 2602.
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`
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`Boost Converters
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`49. The supply voltage required by a power supply generator/moderator
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`in a mobile device is typically provided by the device’s battery. But at times, the
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`battery voltage may be too low, which can distort the output signal from the PA. A
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`boost converter (also known as a “step-up” converter) can prevent this by taking
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`the battery voltage and boosting it to a higher voltage, which then can be supplied
`
`for use by the envelope amplifier. The boost converter receives the supply voltage
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`from the battery and stores it in a storage element that can later release it as a
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`higher voltage.
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`50. Boost converters have been standard components in power electronics
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`for decades. For example, [U.S. Patent No. 5,834,977 (issued November 10, 1998)
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`to Maehara (“Maehara”) discloses a boost (“step-up”) converter that provides
`
`increased voltage to a power amplifier to prevent distortion. Ex. 1018] at Abstract
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`(“An amplifying circuit according to the present invention has an amplifying unit
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`for amplifying an input signal to produce an amplified signal, a battery for
`
`generating a constant voltage (a first voltage), a step-up converter for always
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`generating an increased voltage (or a second voltage) by increasing the constant
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`voltage . . . [B]ecause the increased voltage is always generated by the step-up
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`converter . . . any distortion of the amplified signal can be prevented.”).
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`51. As noted above, Kang discloses a hybrid supply generator that
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`includes a boost converter connected to the envelope amplifier. Ex. 1017 at 2602
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`(“An HSA [hybrid switching amplifier] consists of a boost converter, linear stage,
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`hysteretic comparator, and switching stage, as shown in Fig. 4. The boost
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`converter is connected to the linear stage to boost the output voltage swing.”).
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`52. During prosecution of the ’558 patent, the Examiner acknowledged
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`that boost converters were known: the Examiner found that Kim disclosed a
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`hybrid supply generator with a boost converter and rejected several claims on that
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`basis. See Ex. 1002 at 61-62. The applicant did not dispute the Examiner’s
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`rejection on this ground but instead made a narrowing amendment. Id. at 81-82,
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`86-87.
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`C. Multiplexers
`53. Another well-known component used with hybrid supply generators is
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`a multiplexer. A multiplexer is a circuit with several input signals and a single
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`selectable output signal. U.S. Patent No. 5,870,340 to Ohsawa explains that in a
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`multiplexer, “a signal line is selected from the plurality of signal lines, and the
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`selected signal line is electrically connected to the single signal line.” Ex. 1019
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`[U.S. Patent No. 5,870,340, “Multiplexer” (filed July 8, 1997 and issued February
`
`9, 1999)] at 1:17-20. Multiplexers have long been known as useful for data
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`selection in electronic devices.
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`54. For example, Ohsawa claims a multiplexer circuit using PMOS
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`transistors. Each input signal is connected to the gate of a PMOS transistor, and
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`the drain of each transistor is connected to a common node. Id. at 4:50-5:5, Fig. 4.
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`During operation, the PMOS transistor for the signal to be selected is turned on,
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`which causes that selected signal to be sent to the common node. Id.
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`55. Multiplexers have been used to select between multiple power
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`supplies. For example, Figure 1 of U.S. Patent No. 6,566,935 to Renous shows a
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`two-input multiplexer for selecting between power supplies V1 and V2:
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`
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`Ex. 1020 [U.S. Patent No. 6,566,935,