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`UNITED STATES PATENT AND TRADEMARK OFFICE
`_____________________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`_____________________
`
`
`FEIT ELECTRIC COMPANY, INC.
`Petitioner
`
`v.
`
`PHILIPS LIGHTING HOLDING B.V.
`Patent Owner
`____________________
`
`Case IPR2018-00921
`Patent No. 6,586,890
`_____________________
`
`
`
`DECLARATION OF PETER W. SHACKLE, PH.D.
`IN SUPPORT OF PETITION FOR INTER PARTES REVIEW OF
`U.S. PATENT 6,586,890
`
`
`
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`
`
`
`FEIT 1003
`Feit v. Philips Lighting
`U.S. Pat. No. 6,586,890
`
`
`
`
`
`
`
`Table of Contents
`Introduction ............................................................................................................................. 1
`I.
`II. Qualifications .......................................................................................................................... 3
`III. My Understanding of Claim Construction .......................................................................... 9
`IV. My Understanding of Obviousness ................................................................................... 10
`V. Level of Ordinary Skill in the Art ......................................................................................... 14
`VI.
`The ’890 Patent ................................................................................................................. 14
`A. Current regulation for an LED array ................................................................................. 14
`B.
`Indication that the LED array is inoperable ...................................................................... 24
`C. Claims ............................................................................................................................... 26
`VII. Background of the Technologies Relevant to the ’890 Patent .......................................... 30
`VIII. Claim Construction ........................................................................................................... 34
`A. Claim 7: “means for sensing current to the LED array, said current sensing means
`generating a sensed current signal” ........................................................................................... 34
`B. Claim 7: “means for generating a reference signal” ......................................................... 36
`C. Claim 7: “means for comparing the sensed current signal to the reference signal” ......... 37
`D. Claim 7: “means for modulating pulse width responsive to the feedback signal, said pulse
`width modulating means generating a drive signal” ................................................................. 38
`E. Claim 7: “means for supplying power responsive to the drive signal”............................. 39
`F. Claims 14, 22, and 30: “means for indicating the LED array is inoperable”/“the LED
`array is inoperable”/“LED array inoperable signal” ................................................................. 40
`IX.
`GROUND 1: Biebl renders obvious claims 1, 22, and 30. ............................................... 41
`A. Claim 1 .............................................................................................................................. 46
`B. Claim 15 (now cancelled) ................................................................................................. 56
`C. Claim 23 (now cancelled) ................................................................................................. 65
`D. Claims 22 and 30: LED inoperable claims ....................................................................... 68
`X. GROUND 2: Biebl in view of Hamp in further view of the TI Book renders obvious claims
`7 and 14. ........................................................................................................................................ 73
`A. Claim 7 .............................................................................................................................. 76
`B. Claim 14: “means for indicating the LED array is inoperable” ........................................ 96
`XI.
`GROUND 3: Hamp in view of LT1613 renders obvious claim 7. ................................... 98
`A.
`[7.PRE] “A system for supplying power for an LED array” ............................................ 98
`B.
`[7.A] “means for sensing current to the LED array, said current sensing means generating
`a sensed current signal” ............................................................................................................ 98
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`[7.B] “means for generating a reference signal” ............................................................. 100
`C.
`[7.C] “means for comparing the sensed current signal to the reference signal, said
`D.
`comparing means generating a feedback signal” .................................................................... 103
`E.
`[7.D] “means for modulating pulse width responsive to the feedback signal, said pulse
`width modulating means generating a drive signal” ............................................................... 105
`F.
`[7.E] “means for supplying power responsive to the drive signal, said power supplying
`means supplying current to the LED array” ........................................................................... 108
`XII. GROUND 4: Hamp in view of LT1613 in further view of Biebl renders obvious claim
`14.
`109
`XIII. Conclusion ...................................................................................................................... 111
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`I.
`
`Introduction
`
`I, Dr. Peter Shackle, declare as follows:
`
`1.
`
`I have been retained on behalf of Feit Electric Co. (“Feit”) for the
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`above-captioned inter partes review proceeding. I understand that this proceeding
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`involves U.S. Patent No. 6,586,890 (“the ’890 patent”) titled “LED Driver Circuit
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`with PWM Output.” I understand that Feit challenges the patentability of claims 1,
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`7, 14, 22, and 30 of the ’890 patent. I understand that the ’890 patent was
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`previously challenged in another IPR, IPR2015-01292 (“the ’292 IPR”). The ’292
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`IPR ended with the Board cancelling the ’890 patent’s claims 15 and 23. (FEIT
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`1016, 0002.)
`
`2.
`
`In preparing this declaration, I have reviewed and am familiar with
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`what appear to be true and accurate copies of the following references:
`
`Exhibit
`No.
`1001
`1002
`1005
`1006
`1007
`
`1008
`
`1011
`
`Description
`
`U.S. Patent No. 6,586,890 to Min et al. (“’890 patent”)
`File History of U.S. Patent No. 6,586,890 (“’890 patent”)
`U.S. Patent No. 6,400,101 to Biebl et al. (“Biebl”)
`U.S. Patent Publication No. 2001/0033503 to Hamp et al. (“Hamp”)
`Linear Technology LT1613 Data Sheet, Linear Technology
`Corporation, 1997 (“LT1613”)
`Excerpts from Texas Instruments Power Supply Control Products
`(PS): Data Book, 1999 (“TI Book”)
`Patent Owner’s Mandatory Notices (Paper 53), Wangs Alliance
`Corporation d/b/a WAC Lighting Co. v. Philips Lighting Holding
`B.V., Case No. IPR2015-01292 (P.T.A.B.), April 22, 2016
`
`
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`- 1 -
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`
`
`1012
`
`1013
`
`1014
`
`1015
`
`1016
`
`1017
`
`1018
`
`1019
`
`3.
`
`4.
`
`
`
`
`Institution Decision (Paper 8), Wangs Alliance Corporation d/b/a
`WAC Lighting Co. v. Philips Lighting Holding B.V., Case No.
`IPR2015-01292 (P.T.A.B.), November 25, 2015
`Decision on Request for Rehearing of Institution Decision (Paper
`18), Wangs Alliance Corporation d/b/a WAC Lighting Co. v. Philips
`Lighting Holding B.V., Case No. IPR2015-01292 (P.T.A.B.), January
`26, 2016
`Final Written Decision (Paper 64), Wangs Alliance Corporation
`d/b/a WAC Lighting Co. v. Philips Lighting Holding B.V., Case No.
`IPR2015-01292 (P.T.A.B.), November 23, 2016
`Stipulation of Voluntary Dismissal, Wangs Alliance Corporation
`d/b/a WAC Lighting Co. v. Philips Lighting Holding B.V., Case No.
`17-1530 (C.A.F.C.), June 12, 2017
`Inter Partes Review certificate for Case No. IPR2015-01292 of U.S.
`Patent No. 6,586,890, issued February 7, 2018
`Validity Contentions for the ’890 patent, served by Complainant
`Philips Lighting Holding B.V., LED Lighting Devices, LED Power
`Supplies, and Components Thereof, Investigation No. 337-TA-1081
`(I.T.C.)
`Complainants’ Initial Markman Brief, LED Lighting Devices, LED
`Power Supplies, and Components Thereof,
`Investigation No. 337-TA-1081 (I.T.C.), February 13, 2018
`Respondents’ Initial Markman Brief, LED Lighting Devices, LED
`Power Supplies, and Components Thereof,
`Investigation No. 337-TA-1081 (I.T.C.), February 13, 2018
`
`I have also considered all other materials cited herein.
`
`The ’890 patent describes a “driver circuit for light emitting diodes
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`(LEDs) of the present invention provides power to LEDs using pulse width
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`modulation (PWM).” (FEIT 1001, ’890 patent, Abstract.) I am familiar with the
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`technology described in the ’890 patent as of its 2001 priority date.
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`5.
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`I have been asked to provide my technical review, analysis, insights,
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`and opinions regarding the ’890 patent and the references that form the basis for
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`the grounds of rejection set forth in the Petition for Inter Partes Review of the ’890
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`patent.
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`6.
`
`As set forth below, in my opinion, claims 1, 7, 14, 22, and 30 of the
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`’890 patent are obvious. In particular, I find obviousness on four separate grounds:
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`• Ground 1: Biebl renders obvious claims 1, 22, and 30.
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`• Ground 2: Biebl in view of the TI Book in further view of Hamp renders
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`obvious claims 7 and 14.
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`• Ground 3: Hamp in view of the LT1613 renders obvious claim 7.
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`• Ground 4: Hamp in view of the LT1613 in further view of Biebl renders
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`obvious claim 14.
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`II. Qualifications
`
`7.
`
`I reside at 112 Aspen Way, Rolling Hills Estates, CA 90274. I hold a
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`bachelor’s degree in physics from the University of Birmingham (United
`
`Kingdom) and a Ph.D. in physics from the University of Cambridge (United
`
`Kingdom).
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`8.
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`I have over 20 years’ experience in the field of lighting electronics,
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`with particular emphasis on light emitting diode (LED) drivers and electronic
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`ballasts. I am the President of Photalume, a consulting company I founded in 2012.
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`Before
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`that, I was Director of Power Supply Products at Light-Based
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`Technologies, and I also served as Chief Technology Officer for Lightech
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`Electronics, Inc. Additionally, I held vice president positions at Fulham Co, Inc.,
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`Universal Lighting Technologies, and Robertson Worldwide.
`
`9.
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`I am an elected senior life member of the Institute of Electrical and
`
`Electronics Engineers, and I am a member of the Illuminating Engineering Society.
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`10.
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`I am a named inventor of 61 U.S. patents. I have also authored eight
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`publications in peer reviewed journals and nine publications in trade journals, the
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`most recent of which pertains to LED technology. My curriculum vitae is attached
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`as exhibit 1004.
`
`11.
`
`In 1965, I earned a Bachelor’s degree in physics from the University
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`of Birmingham in the United Kingdom, graduating at the top of my class. In 1969,
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`I earned a Ph.D. in Physics from Trinity College in Cambridge, UK.
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`12. From May 1969 to June 1970, I was a member of technical staff at the
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`GEC Hirst Research Center in Wembley, UK, where I did research on circuits and
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`structures for microwave avalanche diodes.
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`13. From June 1970 to June 1980, I was a member of technical staff at
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`AT&T Bell laboratories in Murray Hill, New Jersey. There, I did research on solid-
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`state devices in general and high-voltage integrated circuits in particular. I became
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`
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`a group supervisor in 1979. I invented the first 500 V integrated circuit, for which I
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`was awarded a prize at the 1981 International Solid State Circuits Conference.
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`14. From June 1980 to November 1983, I was manager of high-voltage
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`integrated circuit products at Harris Semiconductor in Melbourne, Florida. There, I
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`developed high-voltage AC line powered integrated circuits. This work was the
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`subject of a cover page article in Electronics Design magazine.
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`15. From November 1983 to April 1987, I was vice president of
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`engineering for Telmos, Inc. in Sunnyvale, California. There, I developed the first
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`500 V CMOS technology and put numerous high-voltage IC chips into production.
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`In 1986, I chaired the Electrochemical Society symposium on high-voltage and
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`smart power devices. That symposium has since morphed into the conference
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`series known as the IEEE International Symposium on Power Semiconductor
`
`Devices and ICs (ISPSD), which continues to today and is now on its 30th
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`anniversary.
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`16. From April 1987 to August 1991, I was a research department head at
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`Philips Research Laboratories in Briarcliff, New York. There, I worked on the
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`application of power IC technology to all products in the Philips family of
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`companies. I worked on analysis of customer needs and specification of power IC
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`products to meet those needs. I ran a department of 20 employees that produced
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`power IC designs, including chips for fluorescent lighting ballasts.
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`17. From August 1991 to April 1993, I was manager of ballast integrated
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`circuit design at Motorola Lighting Inc. in Buffalo Grove, Illinois. There, I worked
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`on novel ballast circuits suitable for integration into silicon. I also put three
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`conventional ballast circuits into production.
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`18. From April 1993 to October 2000, I was engineering manager and
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`chief technologist at Energy Savings, Inc. in Schaumburg, IL. I worked on
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`fundamental issues making possible the development of low cost, low profile
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`electronic ballasts. I personally designed and put into manufacture 60 ballasts in
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`the first five years. Later, I managed a team of designers and technicians producing
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`ballast designs while personally prototyping the more difficult designs. ESI ballasts
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`combine high performance with low cost & small size with capability for
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`extremely fast product development. I authored multiple inventions involving
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`microprocessor controlled digital ballasts. My responsibilities in this company
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`included all fundamental technology issues and patent related activities. I
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`developed new low cost dimming technology. I personally designed the logical
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`flow charts for microprocessor ballast software. Under my leadership, shipments
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`increased from zero to $40M/yr. in seven years.
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`19. All of the Energy Savings products included a boost front end which
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`boosted up the power line input to a level of 450V DC. In the first few years these
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`boost circuits were self-oscillating for a single voltage, and then later the boost
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`circuits became universal voltage under the control of a boost control IC. All of
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`these products involved PWM power conversion. From October 2000 to May
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`2002, I was V.P. of Engineering at Robertson Worldwide, Blue Island, IL. I
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`managed both electronic and magnetic ballast new product development. I
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`invented a new low cost electronic ballast architecture that still has all the specified
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`features, marketed as the “World Series” ballasts. I trained engineering staff for
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`modern electronic ballast development and assembled state of the art ballast
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`characterization facilities.
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`20. From May 2002 to August 2004, I was Director of Engineering and
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`later V.P. of Advanced Technology at Universal Lighting Technologies, Inc.,
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`Huntsville, AL. I worked on the latest analog and digital technology for electronic
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`ballasts. Product focus was on low cost IC based products and on sophisticated
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`microprocessor based products for more complex applications such as dimming
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`and instant start T5. I ran an operation of 30 people and directly organized a group
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`of nine, including three Ph.D. level staff. My achievements in this position
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`included a line of microprocessor based instant start T5 ballasts and being awarded
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`five patents.
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`21. From August 2004 to December 2007, I was V.P. of Advanced
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`Technology at Fulham Co., Inc., Hawthorne, CA. I was responsible for the
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`technology direction of this fast growing company. My responsibilities included
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`creation of new technologies and development of new products involving
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`innovative technology. My achievements at Fulham included the creation of the
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`Racehorse family of high performance products that are the subject of a Fulham
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`patent application, and the creation of a new charge pump technology for cost
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`effective instant start T8 ballasts, subject of an issued patent. Nine products were
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`transferred to China to be manufactured during this time. I managed design of a
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`four channel LED driver which was transferred to China to be manufactured.
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`22. From January 2008 to December 2010, I was chief technologist at
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`Lightech Electronics North America, Inc. in Torrance, California. I operated a
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`three person laboratory and developed advanced LED drives for this international
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`company. During this time, I developed phase control dimming LED drives
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`capable of dimming to 0.1% using TRIAC dimmers. I put eight such products
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`through UL and into Chinese manufacturing, and three more European products
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`through ENEC approval and into Chinese manufacturing. I developed a
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`dramatically new technology for dimmable constant current LED drives with
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`efficiency of 90%, capable of working at either 120V or 277V. My side
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`responsibilities involved managing the patent portfolio of Lightech internationally.
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`I filed two patent applications during this time.
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`23. During my time at Motorola Lighting, Energy Savings, Robertson
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`World Wide, Universal Lighting and Fulham Lighting, I either carried out or
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`managed the design of roughly 200 products that involved PWM boost technology.
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`All of these products were put through UL or VDE and placed into manufacturing.
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`24. From January 2011 to December 2011, I was Director of Power
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`Supply Products for a company called Light-Based Technologies. There, I again
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`managed a three-person laboratory in Torrance, California developing LED drive
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`application circuits.
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`25. Since January 2012 to present, I have been president and founder of
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`Photalume, a consulting company in the field of lighting electronics products,
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`particularly LED drive circuits and electronic ballast circuits.
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`III. My Understanding of Claim Construction
`
`26.
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`I understand that during an inter partes review, claims of an unexpired
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`patent are to be given their broadest reasonable construction in light of the
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`specification as would be read by a person of ordinary skill in the relevant art
`
`(“skilled artisan” or “POSA”). In reading the claims in view of the specification, I
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`understand that a claim interpretation that excludes the preferred (or only)
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`embodiment disclosed is rarely, if ever, correct.
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`27.
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`I understand a special standard applies when interpreting a means-
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`plus-function claim. Interpreting such a claim, I understand, is a two-step process.
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`The first step is to determine the function of the means-plus-function limitation.
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`The second step is to determine the corresponding structure described in the
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`specification. The claim is interpreted as limited to the specification’s structure and
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`equivalents thereof. To determine whether a structure is equivalent to what the
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`specification discloses, at least two tests are available: (i) the “function-way-result”
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`(FWR) test, i.e., whether the accused product performs substantially the same
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`function in substantially the same way to obtain the same result; and (ii) the
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`“insubstantial differences” test, i.e., whether the accused product or process is
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`substantially different from what is patented.
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`IV. My Understanding of Obviousness
`
`28.
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`I understand that a patent claim is invalid if the claimed invention
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`would have been obvious to a person of ordinary skill in the field at the time the
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`application was filed. This means that even if all of the requirements of the claim
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`cannot be found in a single prior art reference that would anticipate the claim, the
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`claim can still be invalid.
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`29. As part of this inquiry, I have been asked to consider the level of
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`ordinary skill in the field that someone would have had at the time the claimed
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`invention was made. In deciding the level of ordinary skill, I considered the
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`following:
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`• the levels of education and experience of persons working in the field;
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`• the types of problems encountered in the field; and
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`• the sophistication of the technology.
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`30. To obtain a patent, a claimed invention must have, as of the priority
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`date, been nonobvious in view of the prior art in the field. I understand that an
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`invention is obvious when the differences between the subject matter sought to be
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`patented and the prior art are such that the subject matter as a whole would have
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`been obvious at the time the invention was made to a person having ordinary skill
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`in the art.
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`31.
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`I understand that to prove that prior art, or a combination of prior art,
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`renders a patent obvious, it is necessary to: (1) identify the particular references
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`that singly, or in combination, make the patent obvious; (2) specifically identify
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`which elements of the patent claim appear in each of the asserted references; and
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`(3) explain how the prior art references could have been combined in order to
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`create the inventions claimed in the asserted claim.
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`32.
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`I understand that obviousness can be established by combining
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`multiple prior art references to meet each and every claim element. I also
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`understand that to support a combination of multiple prior art references, there
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`must be a rationale explaining why a skilled artisan would have combined the
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`references in the manner claimed, accompanied by a reasonable expectation of
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`success of achieving what is claimed, and how the proposed combination meets
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`each and every claim element of the claim in question. I also understand that a
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`proposed combination of references can be susceptible to hindsight bias. When it
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`appears hindsight bias is being used, I understand the modification or combination
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`is not considered obvious.
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`33.
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`I understand that exemplary rationales that may support a conclusion
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`of obviousness include: combining prior art elements according to known methods
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`to yield predictable results; simple substitutions of one known element for another
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`to obtain predictable results; using a known technique to improve similar devices
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`in the same way; applying a known technique to a known device ready for
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`improvement to yield predicable results; choosing from a finite number of
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`identified, predictable solutions, with a reasonable expectation of success; known
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`work in one field of endeavor may prompt variations of it for use in either the same
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`field or a different field based on design incentives or other market forces if the
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`variations are predicable to one of ordinary skill in the art; and some teaching,
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`suggestion, or motivation in the prior art that would have led one of ordinary skill
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`to modify the prior art reference or to combine prior art teachings to arrive at the
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`claimed invention.
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`34.
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`I understand that if the proposed combination results in one or more of
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`the references being unsatisfactory for its intended purpose, a POSA would not
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`have had a motivation to combine or modify the reference(s).
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`35.
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`I understand that if the proposed combination changes the principle of
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`operation of one or more references, a POSA would not have had a motivation to
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`combine or modify the reference(s).
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`36.
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`I understand that teaching away, e.g., discouragement from making
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`the proposed modification, is strong evidence that the references are not
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`combinable. I also understand that a disclosure of more than one alternative does
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`not necessarily constitute a teaching away.
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`37.
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`I understand that the combination does not need to result in the most
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`desirable embodiment, but if the proposed combination does not have a reasonable
`
`expectation of success at the time of the invention, a POSA would not have had an
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`adequate teaching, suggestion, or motivation to combine the references.
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`38.
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`I understand that the test for obviousness is not whether the features of
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`a secondary reference may be bodily incorporated or physically combined into the
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`structure of the primary reference, but whether the claimed invention is rendered
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`obvious by the teachings of the references as a whole.
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`39.
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`I understand that certain objective indicia can be important evidence
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`regarding whether a patent is obvious or nonobvious. Such indicia include: (1)
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`commercial success of products covered by the patent claims; (2) a long-felt need
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`for the invention; (3) failed attempts by others to make the invention; (4) copying
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`of the invention by others in the field; (5) unexpected results achieved by the
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`invention as compared to the closest prior art; (6) praise of the invention by the
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`infringer or others in the field; (7) the taking of licenses under the patent by others;
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`(8) expressions of surprise by experts and those skilled in the art at the making of
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`the invention; and (9) the patentee proceeded contrary to the accepted wisdom of
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`the prior art.
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`V. Level of Ordinary Skill in the Art
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`40. Based on the disclosure of the ’890 patent, one of ordinary skill in the
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`art would have a B.S. degree in electrical engineering, physics, or an equivalent
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`field, as well as at least 2-4 years of academic or industry experience in circuit
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`design configuration, LED devices, or comparable industry experience. A person
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`of ordinary skill in the art with a higher level of education may have fewer years of
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`academic or industry experience, or vice versa.
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`VI. The ’890 Patent
`
`A. Current regulation for an LED array
`41. The ’890 patent relates to powering LED arrays in, for example,
`
`automobiles. When powering LED arrays, “LED light output is proportional to the
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`LED current.” (FEIT 1001, 1:20-21.) “Driving LEDs at other than nominal current
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`can reduce LED life and produce unpredictable light output.” (Id., 1:27-29.) The
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`’890 patent claims (incorrectly, as I will show with respect to Biebl, who earlier
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`described pulse width modulation current limiting of automotive lights.): “At
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`present, LED drivers in vehicles use driver circuits with voltage source outputs,
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`and current limiting resistors or linear current regulators.” (Id., 1:22-25.) These
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`approaches have drawbacks: “Current limiting resistors cause power loss, making
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`the driver circuits inefficient [and] … current regulation is not precise.” (Id., 1:25-
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`27.)
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`42. To deal with these issues, the ’890 patent describes “a driver circuit
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`for … maintaining operation at the LEDs nominal current,” while offering “good
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`regulation and efficiency.” (Id., 1:39-43.) To maintain nominal current, the ’890
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`patent “us[es] pulse width modulation (PWM)” and “current feedback to adjust
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`power to the LEDs.” (Id., 1:63-67.)
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`43. Pulse width modulation (PWM), which was well known prior to the
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`’890 patent, is a technique where a digital signal is transmitted as a series of pulses.
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`The width of each pulse varies according to an input signal.
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`44. Although PWM can be used to encode a signal, its main use is to
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`control the power supply to electrical devices. A PWM controller circuit controls
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`the average value of voltage or current fed to a load by turning the switch between
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`supply and load on and off at a fast rate. The longer the switch is on compared to
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`the off periods, the higher the total power supplied to the load. The ratio of the
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`duration that the switch is on to the total cycle is known as the duty cycle. Various
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`- 15 -
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`duty cycles are illustrated in the figure below. This operation of PWM controllers
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`was well known long before the ’890 patent.
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`45. Turning back to the ’890 patent, the ’890 patent illustrates its LED
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`driver generally in figure 1 and specifically in figures 2A-D. “FIG. 1 shows a block
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`diagram of a driver circuit for LEDs.” (Id., 1:54-55.) The driver circuit includes a
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`power supply 52 and a PWM control integrated circuit (IC) 56. “The power supply
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`52 can be a DC/DC converter such as a buck-boost power supply or other
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`alternatives, such as a boost, buck, or flyback converter.” (Id., 2:4-6.) It “supplies
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`power for LED array 54 and is controlled by PWM control IC 56, … [which]
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`- 16 -
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`provides a high frequency periodic drive signal of varying pulse width.” (Id., 2:8-
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`9.) PWM control IC 56 varies the pulse width “in response to a feedback signal.”
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`(Id., 2:8-11.) The feedback signal is generated by a comparator 58 “by comparing
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`the sensed current signal from current sensor 60 and the reference signal from
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`reference current source 62.” (Id., 2:14-16.)
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`(FEIT 1001, FIG. 1.)
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`
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`46. Figures 2A-B illustrate an example of a circuit structure disclosed for
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`the block diagram in figure 1. These schematics contain some errors which, if left
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`unexplained, obscure the functionality. To explain my interpretation, I need to
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`address these errors. Figure 2A of the ’890 patent is reproduced below, with
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`highlighted changes. The interpretation I make herein is not to be construed as an
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`admission that I believe the claims to be enabled.
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`- 17 -
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`(FEIT 1001, FIG. 2A (annotated).)
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`
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`47. At the left end of R1A2, I interpret the drawing to include a
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`connection dot symbol, where the red circle is located. Without this connection,
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`which joins the LED array onto the current sense resistors, it is not possible for
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`LED current to flow because otherwise R1A2 only connects to a high impedance
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`input of an op amp. With this dot put in place, it is now possible for current to flow
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`through the LEDs and the current sense resistors R1A1 and R1A3.
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`48. Next, I interpret the drawing to include a dot between the L1A and
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`Q1A drain. Without this, D?1A appears to be in parallel with the LED array, short
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`circuiting it. Also capacitor C11A appears to have its negative terminal connected
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`- 18 -
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`
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`to the power rail containing D1A. Even though the specification recites that the
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`circuitry could be “anything” (flyback, buck, boost, buck-boost etc.) it is never
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`stated in the text what the nature of this circuit actually is. So for the reader it is a
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`decisive step to conjecture that. Even though again, this is never stated in the text
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`of the ’890 patent, with that dot inserted it then becomes apparent that the circuit is
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`a boost, albeit an unusual one as will be discussed shortly. L1A is the boost
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`inductor, however a boost cannot function without a boost diode, and in this case
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`the boost diode is D4A, which is shown shorted. The short has been highlighted in
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`red above. In my interpretation here, I imagine that this short is removed, and then
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`the combination of Q1A, D4A, and L1A together constitute a boost, controlled by
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`the PWM chip U1 in figure 2B. With this understanding, it can now be seen that
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`the rail connected to the cathodes of D4A is the high voltage boost rail. It is at a
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`higher potential than the 12V coming in on the turn pin at top left. With my
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`interpretation here, C11A does have the correct polarity, because the boost rail is at
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`higher potential than the 12V of the turn pin. Diode D?1A is now no longer
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`shorting the LED array, instead it is just a protection device in case of a voltage
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`surge.
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`49. Next, I interpret the drawing to include a connection dot at the right
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`end of R1A2. In order for the boost to be controlled, it is necessary for the leads B
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`and C to be connected across the current sense resistors and then to the input of a
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`
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`- 19 -
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`
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`differential amplifier u3-A in figure 2B. With that dot in position, all three of
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`R1A1, R1A2, and R1A3 constitute the sense resistor. Lead C can connect to the
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`bottom end of the LED array through R3A because normally no current flows
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`through R3A, which is only there to limit the current through Zener diode D?1A in
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`the event of a severe voltage surge condition.
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`50.
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`I note that at least some of these modifications are found in the
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`handwritten drawings that were originally filed. (FEIT 1002, 0028.) Now we need
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`to understand how the PWM chip U1 in figure 2B can control the current through
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`the LEDs. Figure 2B of the ’890 patent is reproduced below.
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`(FEIT 1001, FIG. 2B (annotated).)
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`- 20 -
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`
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`51. On the left you can see the leads B and C coming in from figure 2A.
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`Their signal representing the LED current is amplified by op amp U3-A, thus
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`allowing smaller, lower power resistors to be used fo