Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
`
`
`DOCKET NO.: 0107131-00564US2
`Filed on behalf of Intel Corporation
`By: David L. Cavanaugh, Reg. No. 36,476
`Richard Goldenberg, Reg. No. 38,895
`Wilmer Cutler Pickering Hale and Dorr LLP
`60 State Street
`Boston, Massachusetts 02109
`Email: david.cavanaugh@wilmerhale.com
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` richard.goldenberg@wilmerhale.com
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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
`
`Case IPR2018-01153
`
`
`PETITION FOR INTER PARTES REVIEW OF
`U.S. PATENT NO. 8,698,558
`CHALLENGING CLAIMS 1-9
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`
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`

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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`V. 
`
`TABLE OF CONTENTS
`I. 
`INTRODUCTION ........................................................................................... 1 
`II.  MANDATORY NOTICES ............................................................................. 2 
`A. 
`Real Party-in-Interest ............................................................................ 2 
`B. 
`Related Matters ...................................................................................... 2 
`C. 
`Counsel .................................................................................................. 2 
`D. 
`Service Information ............................................................................... 3 
`III.  CERTIFICATION OF GROUNDS FOR STANDING .................................. 4 
`IV.  OVERVIEW OF CHALLENGE AND RELIEF REQUESTED .................... 4 
`A. 
`Prior Art Patents and Printed Publications ............................................ 4 
`B. 
`Grounds for Challenge .......................................................................... 5 
`BRIEF DESCRIPTION OF TECHNOLOGY ................................................ 6 
`A. 
`Radio Frequency (RF) Power Amplifiers ............................................. 6 
`B. 
`Power Supplies for Power Amplifiers ................................................... 7 
`Envelope Amplifiers ................................................................... 8 
` 
`Switchers ................................................................................... 10 
` 
`Hybrid Supply Generators ........................................................ 11 
` 
`Boost Converters ....................................................................... 16 
` 
`C.  Multiplexers ......................................................................................... 17 
`VI.  OVERVIEW OF THE ’558 PATENT .......................................................... 20 
`A. 
`The Alleged Problem in the Art .......................................................... 20 
`B. 
`The Alleged Invention of the ’558 Patent ........................................... 20 
`C. 
`Relevant Prosecution History .............................................................. 25 
`November 23, 2012 Office Action ........................................... 25 
` 
`February 19, 2013 Amendment ................................................ 26 
` 
`  May 10, 2013 Office Action ..................................................... 27 
`April 15, 2015 Patent Issuance ................................................. 27 
` 
`June 27, 2017 Certificate of Correction .................................... 27 
` 
`VII.  OVERVIEW OF THE PRIOR ART REFERENCES ................................... 28 
`A. 
`Chu ...................................................................................................... 28 
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`B. 
`
`B. 
`Choi 2010 ............................................................................................ 33 
`VIII.  CLAIM CONSTRUCTION .......................................................................... 36 
`A. 
`“envelope signal” (claims 1 and 6-8) .................................................. 36 
`IX.  LEVEL OF ORDINARY SKILL IN THE ART ........................................... 37 
`X. 
`SPECIFIC GROUNDS FOR PETITION ...................................................... 37 
`A.  Ground I: Claims 6 and 8 are obvious over Chu combined with
`Choi 2010 ............................................................................................ 38 
`Claim 6 ...................................................................................... 38 
` 
`Claim 8 ...................................................................................... 56 
` 
`Ground II: Claims 1-9 are obvious over Chu combined with
`Choi 2010 and Myers .......................................................................... 62 
`Claim 1 ...................................................................................... 62 
` 
`Claim 2 ...................................................................................... 76 
` 
`Claim 3 ...................................................................................... 77 
` 
`Claim 4 ...................................................................................... 78 
` 
`Claim 5 ...................................................................................... 79 
` 
`Claims 6 and 8 ........................................................................... 79 
` 
`Claim 7 ...................................................................................... 80 
` 
`Claim 9 ...................................................................................... 81 
` 
`XI.  CONCLUSION .............................................................................................. 82 
`
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`Petitioner Intel Corporation (“Intel”) respectfully requests Inter Partes
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`Review of claims 1-9 of U.S. Patent No. 8,698,558 (the “’558 patent”) (Ex. 1101)
`
`pursuant to 35 U.S.C. §§ 311-19 and 37 C.F.R. § 42.1 et seq.
`
`I.
`
`INTRODUCTION
`The ’558 patent claims structures for “efficiently generating a power supply
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`for a power amplifier.” Ex. 1101 at 1:30-31. Power supply generators for power
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`amplifiers, however, were well-known at the time of the claimed invention, and the
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`challenged claims either are not novel or are obvious variations of known power
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`supply generators. The aspects of the ’558 patent identified by the patent as
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`inventive and that the Patent Owner itself has identified as inventive in parallel
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`litigation (i.e., the addition of a boost converter to an envelope amplifier and the
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`use of an “offset” current to generate a larger supply current) were known in the
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`prior art at the time of the claimed invention, and they provide only known and
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`predictable results that cannot justify a patent.
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`Moreover, the primary prior art references, Chu and Kwak, relied upon in
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`this and related petitions—neither of which was before the Patent Office during
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`prosecution—disclose the key elements that the Examiner found to be allegedly
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`missing from the prior art during prosecution.
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`
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`Accordingly, the prior art cited in this Petition renders obvious claims 1-9 of
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`the ’558 patent.
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`II. MANDATORY NOTICES
`A. Real Party-in-Interest
`Intel Corporation (“Petitioner”) is a real party-in-interest and submits this
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`inter partes review Petition for review of certain claims of U.S. Patent No.
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`8,698,558 (the “’558 patent”). Petitioner also identifies Apple Inc. (“Apple”) as a
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`real party-in-interest.
`
`B. Related Matters
`Qualcomm Incorporated (“Qualcomm” or “Patent Owner”) has asserted
`
`the ’558 patent against Apple in Certain Mobile Electronic Devices and Radio
`
`Frequency and Processing Components Thereof, Investigation No. 337-ITC-1065,
`
`currently pending before the International Trade Commission. Qualcomm also has
`
`asserted the ’558 patent against Apple in Qualcomm Inc. v. Apple Inc., No. 3:17-
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`cv-1375 (S.D. Cal.).
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`Concurrently with this inter partes review Petition, Petitioner is also filing
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`inter partes review petitions for claims 12-14 of the ʼ558 patent (IPR2018-01152),
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`claims 15-20 of the ʼ558 patent (IPR2018-01154), and claims 10 and 11 of the
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`’558 patent (IPR2018-01240). Petitioner requests that these petitions be assigned
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`to the same panel.
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`C. Counsel
`Lead Counsel: David L. Cavanaugh (Registration No. 36,476)
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`Backup Counsel: Richard Goldenberg (Registration No. 38,895), Nina
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`Tallon (pro hac vice to be requested), Joseph Mueller (pro hac vice to be
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`requested), Todd Zubler (pro hac vice to be requested), Kathryn Zalewski (pro hac
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`vice to be requested), and Theodoros Konstantakopoulos (Registration No. 74,155)
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`D.
`Service Information
`E-mail:
`
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`david.cavanaugh@wilmerhale.com
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`richard.goldenberg@wilmerhale.com
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`nina.tallon@wilmerhale.com
`
`joseph.mueller@wilmerhale.com
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`todd.zubler@wilmerhale.com
`
`kathryn.zalewski@wilmerhale.com
`
`theodoros.konstantakopoulos@wilmerhale.com
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`Post and hand delivery: Wilmer Cutler Pickering Hale and Dorr LLP
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`
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`
`
`60 State Street
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`Boston, Massachusetts 02109
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`Telephone: (617) 526-6000
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`Fax: (617) 526-5000
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`Petitioner consents to email delivery on lead and backup counsel.
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`III. CERTIFICATION OF GROUNDS FOR STANDING
`Petitioner certifies pursuant to Rule 42.104(a) that the patent for which
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`review is sought is available for inter partes review and that Petitioner is not
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`barred or estopped from requesting an inter partes review challenging the patent
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`claims on the grounds identified in this Petition.
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`IV. OVERVIEW OF CHALLENGE AND RELIEF REQUESTED
`Pursuant to Rules 42.22(a)(1) and 42.104(b)(1)-(2), Petitioner challenges
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`claims 1-9 of the ’558 patent.
`
`A.
`Prior Art Patents and Printed Publications
`The ’558 patent was filed June 23, 2011 and does not claim priority to any
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`prior applications.
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`The following references are pertinent to the grounds of unpatentability
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`explained below:
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`1.
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`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
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`(2008) (“Chu”) (E. 1104). Chu was published in 2008 and is prior art
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`under at least 35 U.S.C. § 102(b). Ex. 1105 at ¶14.
`
`2.
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`Choi, J. et al., “Envelope tracking power amplifier robust to battery
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`depletion,” Microwave Symposium Digest (MTT), 2010 IEEE MTT-
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`S International 1332-36 (2010) (“Choi 2010”) (Ex. 1106). Choi 2010
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`has been available from the IEEE Xplore website at
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`http://ieeexplore.ieee.org/abstract/document/5517825/ since July 23,
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`2010 and is therefore prior art under at least 35 U.S.C. § 102(a). Ex.
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`1107 at ¶11. Choi 2010 is also prior art under 35 U.S.C. § 102(b).
`
`Choi 2010 was presented in May 2010 at a leading technical
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`conference of skilled artisans, the IEEE International Microwave
`
`Symposium (“IMS”) 2010 conference, in Anaheim, California. Ex.
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`1108 at ¶¶8-9; Ex. 1106 at cover; Ex. 1109 at ¶¶4-5; Ex. 1107 at ¶11.
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`Choi 2010 was distributed to hundreds of conference attendees via
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`USB drives in May 2010. Ex. 1108 at ¶17; Ex. 1109 at ¶¶6-9.
`
`3.
`
`U.S. Patent No. 5,929,702, “Method and Apparatus for High
`
`Efficiency High Dynamic Range Power Amplification,” Myers et al.
`
`(“Myers”) (Ex. 1112). Myers was filed on November 28, 1997 and
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`issued on July 27, 1999, making it prior art under at least 35 U.S.C.
`
`§ 102(a), (b), and (e).
`
`B. Grounds for Challenge
`Petitioner requests cancellation of claims 1-9 of the ’558 patent as
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`unpatentable under 35 U.S.C. § 103. This Petition, supported by the declaration of
`
`Dr. Alyssa Apsel (Ex. 1103) filed herewith, demonstrates that there is a reasonable
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`likelihood that Petitioner will prevail with respect to cancellation of at least one
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`challenged claim. See 35 U.S.C. § 314(a).
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`V. BRIEF DESCRIPTION OF TECHNOLOGY
`The challenged claims of the ’558 patent are directed to an apparatus for
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`generating a power supply signal for a power amplifier. The apparatus includes
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`several components that were well known in the art—envelope amplifiers, boost
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`converters, and power amplifiers—as explained below. Ex. 1103 at ¶33.
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`A. Radio Frequency (RF) Power Amplifiers
`In wireless communications, mobile devices exchange information (such as
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`phone calls, text messages, or other data to and from the Internet) with a base
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`station that connects the mobile devices to other devices and a wider network.
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`This information is transmitted using radio frequency (“RF”) signals. To reach a
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`base station or a mobile device, RF signals require a certain amount of power.
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`Mobile devices and base stations therefore commonly contain a component known
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`as a “power amplifier” (or “PA”) that increases the power of RF signals to a level
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`sufficient to reach the receiving base station or mobile device. Typically, the
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`further the device moves from a base station, the more power amplification is
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`needed to ensure successful transmission of the RF signal. Ex. 1103 at ¶¶34-35.
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`In operation, a PA accepts an input signal (such as the signal that carries
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`voice data for a cell phone call) and produces an output signal that, ideally,
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`replicates the input signal but with proportionally greater power. Ex. 1103 at ¶36.
`
`B.
`Power Supplies for Power Amplifiers
`A PA needs to receive power sufficient to amplify the input signal. A PA
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`typically receives its power in the form of a supply voltage from a power supply
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`generator/modulator. For example, in the prior-art structure shown below, the PA
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`receives a supply voltage (“Modulated Supply”) from a power supply generator
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`(“Supply Modulator”):
`
`
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`Kim – Figure 1(b)
`
`Ex. 1113 [Kim, D. et al., “High Efficiency and Wideband Envelope Tracking
`
`Power Amplifier with Sweet Spot Tracking,” Radio Frequency Integrated Circuits
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`Symposium (RFIC): 255-258 (2010) (“Kim”)] at 255. The supply voltage provides
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`the PA with sufficient power to transmit an output signal (“RF_OUT”) based on
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`the input signal (“RF_IN”) that the PA receives, without degrading the quality of
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`the signal or wasting power through resistive losses. The amount of power
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`required at the RF PA depends on the RF signal to be transmitted. Ex. 1103 at
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`¶¶37-38.
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`Envelope Amplifiers
`An envelope amplifier—also sometimes referred to as a “linear amplifier”—
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`is one type of power supply generator for a PA. As shown in the diagram above,
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`the envelope amplifier (the “Supply Modulator”) receives an “envelope” signal,
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`which is a signal that tracks the RF signal to be transmitted. As shown in the
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`diagram below, the envelope signal (shown in blue) tracks the outermost points of
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`the oscillating RF signal (shown in black):
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`Ex. 1103 at ¶¶39-40. The envelope amplifier receives the envelope signal and uses
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`it to provide a supply voltage to the PA that increases and decreases as the
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`amplitude of the envelope signal increases and decreases. Ideally, the power
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`provided to the PA will match the envelope signal as closely as possible—thereby
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`providing the power that the PA needs to transmit the RF signal, but without
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`providing more power than necessary. Ex. 1103 at ¶40.
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`Envelope amplifiers have many advantages: they have a simple circuit
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`configuration; they can generate output signals that are accurate copies of the input
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`signals, even when the input changes rapidly (i.e., when the RF signal has a high
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`bandwidth); and they do not generate significant noise that could affect other
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`circuits. Ex. 1103 at ¶41.
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`Envelope amplifiers, however, are also energy inefficient and generate
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`considerable heat. To generate a voltage for the PA, an envelope amplifier
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`requires its own input supply voltage. An envelope amplifier is a type of “linear
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`regulator,” which is a device that takes an input voltage and reduces (or “steps-
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`down”) that voltage as necessary to generate the output supply voltage for the PA.
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`This step-down in voltage is necessarily inefficient because it involves dissipating
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`the power difference between the input and output voltages in the form of heat.
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`Using an envelope amplifier alone to supply power to a PA therefore consumes
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`more power than desired. Ex. 1103 at ¶41.
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`IPR2018-01153
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`Switchers
`Another prior art device for supplying power to a PA is a “switcher,” also
`
`sometimes referred to as a “switching regulator” or “switching amplifier.” A
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`switcher takes small chunks of energy from an input voltage source and stores
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`them in energy-storing elements (such as an inductor) that will transform the
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`energy into an output. A switcher accomplishes this task by alternately connecting
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`and disconnecting the input supply voltage (e.g., the battery of the mobile device)
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`to the energy-storage element. When the switcher connects the input supply
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`voltage to the energy storage element, energy is added to the storage element. The
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`storage element can then release this energy in the form of a steady current to the
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`PA. By controlling the timing of these alternating connections / disconnections to
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`increase the energy in the storage element, a switcher can supply energy to a PA
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`without dissipating voltage as heat, like an envelope amplifier does. The energy
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`losses involved in moving chunks of energy around in this way are thus relatively
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`small. Ex. 1103 at ¶¶42-43.
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`As a result, switchers generally achieve higher efficiency than envelope
`
`amplifiers. But there are limits on the frequency at which switchers can operate.
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`Because of this, switchers were generally known to have higher efficiency, but
`
`lower operating bandwidth, than envelope amplifiers. Ex. 1103 at ¶43.
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` Hybrid Supply Generators
`Hybrid supply generators combine envelope amplifiers and switchers to gain
`
`the benefits of both. A hybrid supply generator can use the envelope amplifier
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`and/or the switcher, as appropriate, to supply the power to a power amplifier,
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`thereby obtaining both (a) the high frequency response of an envelope amplifier,
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`and (b) the high efficiency of a switcher. Ex. 1103 at ¶44.
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`Hybrid supply generators were well known in the art at the time of the
`
`purported invention of the ’558 patent. For example, another patent filed eleven
`
`years earlier by the lead inventor of the ’558 patent discloses combining a linear
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`amplifier with a type of switcher known as a synchronous buck DC/DC converter.
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`Ex. 1114 [U.S. Patent No. 6,300,826, “Apparatus and Method for Efficiently
`
`Amplifying Wideband Envelope Signals” (filed May 5, 2000) (“Mathe ’826”)]. As
`
`shown below, circuit 110 in Mathe ’826 is a circuit that includes (1) an envelope
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`amplifier (“an AB-type RF amplifier 122” highlighted in purple), which is
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`described as “a moderately power efficient device having high bandwidth
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`capabilities”, and (2) a switcher (“synchronous buck DC/DC converter 124”
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`highlighted in yellow), which is described as “a highly efficient device having low
`
`bandwidth capabilities.” Id. at 5:17-22; Ex. 1103 at ¶45.
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`Mathe ’826 – Figure 6
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`
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`A paper by Ertl from 1997 also discloses a hybrid supply generator. Ex.
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`1116 [Ertl, H. et al., “Basic considerations and topologies of switched-mode
`
`assisted linear power amplifiers,” IEEE Transactions on Industrial Electronics
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`44.1 (1997): 116-123 (“Ertl”)]. Ertl presents “a combined power amplifier system”
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`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:
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`Ertl – Figure 2
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`
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`Ex. 1116 at 117. Ertl touts this combination as providing the best of both worlds:
`
`(a) “the fundamental drawback of conventional linear power amplifiers—the high
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`loss—is avoided;” and (b) “[c]ompared to a pure class D (switching) amplifier, the
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`presented system needs no output filter to reduce the switching frequency
`
`harmonics.” Id.; Ex. 1103 at ¶46.
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`Blanken also proposes a hybrid supply modulator for a PA, combining “a
`
`high-bandwidth class-AB linear regulator [envelope amplifier] with an efficient
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`DC/DC converter [switcher] in a master-slave configuration.” Ex. 1110 [Blanken,
`
`P.G. et al., “A 50MHz bandwidth multi-mode PA supply modulator for GSM,
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`EDGE and UMTS application,” 2008 Radio Frequency Integrated Circuits
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`Symposium (IEEE) 401-04 (2008) (“Blanken”)] at 401. Blanken explains that:
`
`[h]igh-efficiency voltage conversion can be obtained with a switched-
`mode inductive DC/DC buck converter, but its bandwidth is limited
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`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
`
`linear regulator supplies the high-frequency part.”). Ex. 1103 at ¶47.
`
`Finally, a 2010 paper by Kang describes “a highly efficient supply
`
`modulator” that combines an envelope amplifier with a switcher. Ex. 1117 [Kang,
`
`D. et al., “A multimode/multiband power amplifier with a boosted supply
`
`modulator,” IEEE Transactions on Microwave Theory and Techniques 58.10
`
`(2010): 2598-2608 (“Kang”)]. Kang acknowledges the disadvantages of both
`
`linear amplifiers (i.e., envelope amplifiers) and switching amplifiers (i.e.,
`
`switchers): “the limited BW [bandwidth] of switching amplifiers and the low
`
`efficiency of wideband linear amplifiers.” Ex. 1117 at 2599. Kang explains that
`
`researchers therefore have utilized both envelope amplifiers and switchers in
`
`hybrid systems that are “suitable for the envelope signal of modern wireless
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`communication systems, which has the most power in the low-frequency region.”
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`Id. at 2599. Kang specifically proposes “a hybrid switching amplifier (HSA) for
`
`multistandard applications.” As shown in Figure 4 below, Kang’s hybrid supply
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`generator includes not only an envelope amplifier (“linear stage”) and a switcher
`
`(“switching stage”), but also a boost converter (highlighted in light blue and
`
`discussed further in the next section):
`
`Kang – Figure 4
`
`
`
`Ex. 1117 at 2602; Ex. 1103 at ¶48.
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`Boost Converters
`If the supply voltage from a device’s battery is too low, the output signal
`
`from the PA can be distorted. A boost converter (also known as a “step-up”
`
`converter) can prevent this by boosting the battery voltage to a higher voltage,
`
`which the envelope amplifier can then use to provide power to the PA. This
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`boosting capability is achieved by storing energy in a storage element, and then
`
`releasing the energy in the form of a higher voltage. Ex. 1103 at ¶49.
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`Boost converters have been standard components in power electronics since
`
`well before the earliest alleged priority date of the ʼ558 patent. For example, a
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`patent from the 1990s discloses a boost (“step-up”) converter that provides
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`increased voltage to a power amplifier to prevent distortion. Ex. 1118 [U.S. Patent
`
`No. 5,834,977, “Amplifying Circuit with Power Supply Switching Circuit” (filed
`
`October 30, 1996 and issued November 10, 1998) (“Maehara”)] at Abstract (“An
`
`amplifying circuit according to the present invention has an amplifying unit 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 generating an
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`increased voltage (or a second voltage) by increasing the constant voltage ….
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`[B]ecause the increased voltage is always generated by the step-up converter …
`
`any distortion of the amplified signal can be prevented.”). Ex. 1103 at ¶50.
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`Similarly, as noted in the preceding section, the Kang paper from 2010
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`discloses a hybrid supply generator that includes a boost converter connected to the
`
`envelope amplifier. Ex. 1117 at 2602 (“An HSA [hybrid switching amplifier]
`
`consists of a boost converter, linear stage, hysteretic comparator, and switching
`
`stage, as shown in Fig. 4. The boost converter is connected to the linear stage to
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`boost the output voltage swing.”). Ex. 1103 at ¶51.
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`Finally, during prosecution, the Examiner found that Kim disclosed a hybrid
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`supply generator with a boost converter, as required by the ’558 patent. See Ex.
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`1113. The Examiner initially rejected patent claims 6-8 and 10-11 (prosecution
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`claims 10-12, 14-15) because Kim disclosed, among other things, the required
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`boost converter. Ex. 1102 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; Ex. 1103 at ¶52.
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`C. Multiplexers
`A multiplexer is a circuit with several input signals and a single selectable
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`output signal. As U.S. Patent No. 5,870,340 to Ohsawa explains, “a signal line is
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`selected from the plurality of signal lines, and the selected signal line is electrically
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`connected to the single signal line.” Ex. 1119 [U.S. Patent No. 5,870,340,
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`“Multiplexer” (filed July 8, 1997 and issued February 9, 1999)] at 1:17-20. At the
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`time of the alleged invention, it was well known that multiplexers could be used
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`for data selection in many electronic devices. Ex. 1103 at ¶53.
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`For example, Ohsawa discloses 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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`When an input signal is to be selected, the PMOS transistor associated with that
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`signal turns on, which sends the signal to the common node. Id. Ex. 1103 at ¶54.
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`Such multiplexers have been used to select between power supplies. A two-
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`input multiplexer for selecting between power supplies V1 and V2 is shown in
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`Figure 1 of U.S. Patent No. 6,566,935 to Renous:
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`
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`Renous – Figure 1
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
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`Ex. 1120 [U.S. Patent No. 6,566,935, “Power Supply Circuit With a Voltage
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`Selector” (filed August 28, 2000 and issued May 20, 2003)] at Fig. 1. Renous
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`explains that Figure 1 “shows a conventional power supply circuit receiving two
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`supply voltages V1 and V2 on two respective supply lines L1 and L2, and
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`providing a voltage Vdd on an output node S.” Ex. 1120 at 1:14-17; Ex. 1103 at
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`¶55.
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`The multiplexer uses two PMOS transistors (T1 and T2) to implement the
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`selection between the two supply voltages (V1 and V2). A comparator A1
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`determines which voltage supply should be used. The comparator A1 sends one
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`control signal to the gate of transistor T1 and a second control signal (which is an
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`inverted version of the first control signal) to the gate of transistor T2. This will
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`activate one or the other of the transistors and thereby send one of the supply
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`voltages (V1 or V2) to the output node S. Ex. 1120 at 1:17-25 (“the output of
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`comparator A1 is at a low level when voltage V1 is greater than voltage V2 and at
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`a high level otherwise. The output of comparator A1 is directly connected to the
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`gate of transistor T1, and is connected to the gate of transistor T2 via an inverter
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`I1.”). Ex. 1103 at ¶56.
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
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`VI. OVERVIEW OF THE ’558 PATENT
`A. The Alleged Problem in the Art
`The ’558 patent describes “techniques for efficiently generating a power
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`supply for a power amplifier and/or other circuits.” Ex. 1101 at 1:30-31. The ’558
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`patent explains that although it is advantageous to operate a wireless device using a
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`low battery voltage to reduce power consumption and extend battery life, a power
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`amplifier sometimes “may need to operate with a PA supply voltage (e.g., 3.2V)
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`that is higher than the battery voltage.” Id. at 3:51-52. The ’558 patent also
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`acknowledges that it was known to use boost converters to generate the necessary
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`higher PA supply voltage. See id. at 3:52-54. But the ’558 patent says using a
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`boost converter to “directly supply the PA supply voltage” may “increase cost and
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`power consumption.” Id. at 3:54-56. Ex. 1103 at ¶57. These alleged problems,
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`however, had already been identified and solved in the prior art before the filing of
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`the ’558 patent, as discussed below.
`
`B.
`The Alleged Invention of the ’558 Patent
`The challenged claims of the ’558 patent comprise combinations of well-
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`known components in the field: specifically, PAs, envelope amplifiers, switchers,
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`hybrid supply generators (envelope amplifier + switcher), and boost converters.
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`The ’558 patent does not claim to have invented any of these components, all of
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`Petition for Inter Partes Review of U.S. Patent No. 8,698,558
`IPR2018-01153
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`which were known in the prior art years before the filing date of the ’558 patent, as
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`explained above. Ex. 1103 at ¶58.
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`The ’558 patent purports to provide two alleged improvements to hybrid
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`supply generators: (1) connecting a boost converter to the envelope amplifier; and
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`(2) adding an “offset” current to the switcher’s input current to increase the amount
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`of current generated by the switcher.1 Ex. 1103 at ¶58. As explained in this
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`Petition, each of these techniques was known in the prior art.
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`First, the ’558 patent proposes a hybrid supply generator with a specific type
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`of envelope amplifier—i.e., one connected to a boost converter, as shown below in
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`Figure 3 from the ’558 patent:
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`
`1 These are the only two allegedly inventive aspects that the Patent Owner has
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`identified in the parallel ITC litigation. See Ex. 1122 at 12-15 (“First, the ‘558
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`patent discloses connecting a boost converter (which ‘boosts’ or increases the
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`battery voltage to a higher level) only with the envelope amplifier, and not the
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`switcher, to reduce overall usage of the boost converter. … Second, the ‘558 patent
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`discloses that an ‘offset’ may be used to increase the amount of current generated
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`by the switcher.”).
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`’558 Patent – Figure 3
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`
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`The envelope amplifier 170a (highlighted in purple) and switcher 160a
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`(highlighted in yellow) cooperate to provide power to power amplifier 130
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`(highlighted in red). The envelope amplifier receives an envelope signal
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`(highlighted in dark blue). The boost converter 180 (highlighted in light blue) is
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`connected to the envelope amplifier and adds extra voltage to the envelope
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`amplifier when needed. According to the patent, this configuration is efficient
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`because the boost converter will provide extra voltage only when the envelope
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`Petit