DEVELOPMENT OF A LARGE SCALE FLEXIBLE LED
`DISPLAY MATRIX FOR THE SCREEN INDUSTRY
`
`Dominic Michael Xavier, BEng Infomechatronics
`
`
`
`
`
`
`
`Prof. Duncan Campbell
`Dr. Michael Mason
`
`Submitted in fulfilment of the requirements for the degree of
`Master of Engineering (Research)
`Faculty of Built Environment and Engineering
`Queensland University of Technology
`2013
`
`Samsung Exhibit 1027
`Samsung Elecs. Co., Ltd. v. Ultravision Techns., LLC
`IPR2020-01176
`Page 00001
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`Keywords
`
`Light-emitting diode displays; Image communication; Smart pixels; Light-emitting
`diodes; Color graphics; DC-DC power conversion; Image processing; Magnetic
`circuits; Thermal factors
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`Abstract
`
`Significant opportunities exist in the display market, which require high quality,
`highly portable, easily managed displays. However current technology struggles to
`fill this need, often requiring large construction equipment, multiple signal
`processing layers and large power requirements. This research has developed an 18
`meters squared full scale prototype display that meets these requirements.
`
`The display development is driven by the increasing need to present information and
`graphics to larger audiences in more temporary and flexible formats. The need for
`portability, fast setup, easy reconfiguration and multiple uses has driven the need for
`light, efficient, easily erected, high quality displays. Through collaboration with
`multiple industry representatives, the display was designed to meet expectations of
`visual quality, portability, and display management, influenced by the LED
`arrangement, power efficiency, thermal regulation and physical construction.
`
`The display is comprised of a series of illuminated elongated members juxtaposed to
`create a dynamic image. The design seeks advantage in the physical construction of
`the system to achieve high visual quality, efficient operation in a calibrated panel,
`and passive thermal management, achieved in a commercially viable environment. A
`novel method of pitch adjustment is proposed for future designs that could further
`enhance the portability of the display, opening up opportunities for displays much
`larger than currently available, while still remaining ultra-portable.
`
`The key outcomes of this research include an operational, full scale prototype
`display, which implements large LED display colour aliasing, a purely passive
`thermal management solution, a rapid deployment system, individual seven bit LED
`current control with two way display communication, auto-configuration and
`complete signal redundancy, all of which are in direct response to industry needs.
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`Table of Contents
`
`Keywords ...................................................................................................................... i
`
`Abstract ....................................................................................................................... iii
`
`Table of Contents ........................................................................................................ iii
`
`List of Figures ............................................................................................................ vii
`
`List of Tables............................................................................................................ xxii
`
`List of Supplementary Material ............................................................................... xxv
`
`List of Abbreviations............................................................................................... xxvi
`
`Statement of Original Authorship .......................................................................... xxvii
`
`Acknowledgements ............................................................................................... xxviii
`
`Chapter 1
`
`Chapter 2
`
`Introduction ...................................................................................... 1
`
`The Large Scale Display Market ..................................................... 4
`
`2.1 Market Definition ............................................................................................ 4
`
`2.2 Market Trends ................................................................................................ 13
`
`2.3
`
`Industry Correspondence ............................................................................... 14
`
`2.4 Chapter Conclusions ...................................................................................... 18
`
`Chapter 3
`
`LED Technology............................................................................ 19
`
`3.1 LED Calibration ............................................................................................. 20
`
`3.2 Direct Current Control ................................................................................... 36
`
`3.3 Direct Control LED Sign Classification ........................................................ 43
`
`3.4 Active Current Control .................................................................................. 47
`
`3.5 LED Lifetime Curves..................................................................................... 55
`
`3.6 LED Intensity/Efficiency Improvements ....................................................... 58
`
`3.7 Chapter Conclusions ...................................................................................... 59
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`Chapter 4
`
`Display Luminance and Gamut...................................................... 60
`
`4.1 Display Luminance ........................................................................................ 60
`
`4.2 Display Gamut ............................................................................................... 74
`
`4.3 Chapter Conclusions ...................................................................................... 94
`
`Chapter 5
`
`Previous Prototype Display ............................................................ 96
`
`5.1 Display Structure ........................................................................................... 96
`
`Chapter 6
`
`LED Arrangement and Visual Fidelity ........................................ 103
`
`6.1 LED Density ................................................................................................ 107
`
`6.2 LED Arrangement ........................................................................................ 114
`
`6.3 Gloss and Matt Finishes ............................................................................... 121
`
`6.4 Display Panel Alignment ............................................................................. 129
`
`6.5 Driver Selection ........................................................................................... 131
`
`6.6 Chapter Conclusions .................................................................................... 135
`
`Chapter 7
`
`LED Board Power Optimisation .................................................. 138
`
`7.1 Efficiency of LEDs ...................................................................................... 138
`
`7.2 Optimisation of the Driver Circuits ............................................................. 144
`
`7.3 Power Loss Optimisation of the Conversion Circuits .................................. 147
`
`7.4 Final Design ................................................................................................. 154
`
`7.5 Chapter Conclusions .................................................................................... 160
`
`Chapter 8
`
`Thermal Management .................................................................. 163
`
`8.1 Tube Material and Profile ............................................................................ 163
`
`8.2 Material Testing – LEXAN SLX ................................................................. 164
`
`8.3 Tube Material Options ................................................................................. 171
`
`8.4 Thermal Coupling ........................................................................................ 175
`
`8.5 Other Thermal Considerations ..................................................................... 179
`
`8.6 Alternate Solution ........................................................................................ 182
`
`8.7 Construction ................................................................................................. 185
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`8.8 Chapter Conclusions .................................................................................... 191
`
`Chapter 9
`
`Physical Display Structure ........................................................... 193
`
`9.1 Current Fixed Display Structure .................................................................. 193
`
`9.2 Display Transparency .................................................................................. 201
`
`9.3 Dynamic Structure ....................................................................................... 204
`
`9.4 Electrical Implementation for Physical Structure ........................................ 216
`
`9.5 Chapter Conclusions .................................................................................... 229
`
`Chapter 10
`
`Communication and Control Architecture ................................... 231
`
`10.1 Signal Redesign Process ............................................................................ 237
`
`10.2 Test Board Design ..................................................................................... 246
`
`10.3 Segment Controller Design ........................................................................ 250
`
`10.4 LED Board Signal Structure ...................................................................... 257
`
`10.5 A6280 Scrambling ..................................................................................... 265
`
`10.6 Final Design ............................................................................................... 268
`
`10.7 A6281 Sparkle ........................................................................................... 272
`
`10.8 Chapter Conclusions .................................................................................. 278
`
`Chapter 11
`
`Conclusions and Recommendations ............................................ 280
`
`11.1 Discussion .................................................................................................. 280
`
`11.2 Research Outcomes.................................................................................... 290
`
`Reference List .......................................................................................................... 292
`
`Appendix A:
`
`Company Profile .......................................................................... 301
`
`Appendix B:
`
`LED Characteristics Data Interpolation ....................................... 310
`
`Appendix C:
`
`LED Intensity and Density Calculations ..................................... 320
`
`Appendix D:
`
`LED Intensity and PWM cycle .................................................... 326
`
`Appendix E:
`
`Tabulated Power Supply Testing Results .................................... 330
`
`Appendix F:
`
`Materials Table ............................................................................ 336
`
`Appendix G:
`
`Thermally Conductive Materials ................................................. 337
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`Appendix H:
`
`Design Option Matrix .................................................................. 338
`
`Appendix I:
`
`LED Board Schematics and Layout Prints .................................. 353
`
`Appendix J:
`
`Test Board Overlay Prints and Schematics .................................. 362
`
`Appendix K:
`
`Segment Controller Overlay Prints and Schematics .................... 366
`
`Appendix L:
`
`Segment Controller Test Board Targets....................................... 375
`
`Appendix M:
`
`PIC16F Code for 16LED Prototype Board .................................. 377
`
`Appendix N:
`
`Segment Controller Re-work Tracking Sheets ............................ 385
`
`Appendix O:
`
`BOM for Test Boards ................................................................... 392
`
`Appendix P: Wavelength and Doping Materials .............................................. 395
`
`Appendix Q:
`
`Core Area Calculation .................................................................. 397
`
`Appendix R:
`
`Ivoke: LAADtech 3.0 Visual Brief March 08.............................. 402
`
`Appendix S:
`
`Mass Transit Design Document ................................................... 404
`
`Appendix T:
`
`Colour Matching Functions Data ................................................. 423
`
`Appendix U: MII Further Pin Explanation ........................................................ 425
`
`Appendix V:
`
`Segment Controller Code ............................................................. 428
`
`Appendix W:
`
`Dynamic Pitch Board Configuration ........................................... 466
`
`Appendix X:
`
`SC Control Code table ................................................................. 468
`
`Appendix Y: Meeting Minutes and Interviews.................................................. 471
`
`Appendix Z:
`
`Component Descriptions .............................................................. 495
`
`Appendix AA: Allegro 6280 Data Sheet .............................................................. 501
`
`Appendix BB: Allegro 6281 Data Sheet .............................................................. 507
`
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`List of Figures
`
`Figure 1.1
`
`LAADtech fullscale prototype display ............................................ 3
`
`Figure 2.1
`
`Hong Kong Light Festival 2007-2008 [6] ....................................... 6
`
`Figure 2.2
`
`Stadium Advertising/informational full colour display.
`Woolloongabba Stadium, picture taken: 13/12/2007 ...................... 7
`
`Figure 2.3
`
`Post Office Square LED display, Queen St, Brisbane CBD. .......... 8
`
`Figure 2.4
`
`Figure 2.5
`
`Figure 2.6
`
`Figure 2.7
`
`Figure 2.8
`
`Figure 2.9
`
`VMS signs are often rented out for advertising very
`effectively because passersby expect to see critical road
`condition information on them. ....................................................... 9
`
`DriverTron’s seven meter display positioned on Moggill
`Road Indooroopilly. Picture Taken: 3/10/2009, 12:43pm,
`Moggill Road Indooroopilly. ......................................................... 10
`
`3 tonne base for DriverTron’s portable display, requiring a
`crane and 3 tonne truck for transportation. .................................... 10
`
`Hutchinsons crane on SouthBank at night, photo taken:
`22/09/2009 6:56p and Hutchinsons crane on SouthBank at
`day, photo taken 23/09/2009 6:46am ............................................ 12
`
`SideTrack subway media installation of multiple frames
`illuminated briefly in time with the train passing [8] .................... 12
`
`Longer view of SideTrack installation in subway tunnel
`showing illumination technique [8] ............................................... 12
`
`Figure 3.1
`
`Relative luminous intensity vs. forward current [24] .................... 22
`
`Figure 3.2
`
`Figure 3.3
`
`intensity vs. forward current for
`luminous
`Relative
`T676 diodes from OOS[25] ........................................................... 23
`
`Relative luminous intensity vs. junction temperature for
`T676 diodes from OOS [25] .......................................................... 26
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`Figure 3.4
`
`Figure 3.5
`
`Figure 3.6
`
`Figure 3.7
`
`Close up of Post Office Square display, Brisbane CBD.
`Each panel contains 32x16 pixels, picture taken:9/09/2009
`8:39am ........................................................................................... 33
`
`8x7 panel Post Office Square display, total 256x112 pixels
`showing the use of panels made from different bins in a
`single display. This display is termed by professionals as
`‘poor quality’ and corresponds to large variation in intensity
`and wavelength of LEDs utilised in the display, picture
`taken: 9/09/2009, 8:34am .............................................................. 33
`
`OSRAM recommends the use of single bins for displays,
`this means that panels from display B can never be mixed
`with panels from display A [32]. ................................................... 34
`
`Inhomogeneous display configurations, commonly called
`‘tiling’. The bottom
`left hand corner panel
`is an
`inhomogeneous panel containing a patterned distribution of
`both bins a and b [32]. ................................................................... 34
`
`Figure 3.8
`
`Equivalent Circuit of LED ............................................................. 36
`
`Figure 3.9
`
`Series connected LED driver circuit .............................................. 37
`
`Figure 3.10
`
`Minimal component parallel LED driver circuit ........................... 39
`
`Figure 3.11
`
`Minimum component parallel circuit equivalent ........................... 40
`
`Figure 3.12
`
`Modified parallel connected LED drive circuit ............................. 41
`
`Figure 3.13
`
`Matrix connected LED drive circuit .............................................. 42
`
`Figure 3.14
`
`Dynamic speed sign showing uneven degradation of LEDs ......... 44
`
`Figure 3.15
`
`Figure 3.16
`
`Bus stop mixed dynamic/static advertisement on Queen St.
`Brisbane CBD. Single colour, pre-programmed, non-
`remotely updatable content. Photo taken: 9/9/2009 8:28am ......... 45
`
`Leading Edge computer store, Moggill Road Taringa.
`Single colour, co-ordinated matrix across two display’s.
`Photo taken: 3/10/2009 1:06pm ..................................................... 46
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`Figure 3.17
`
`QUT welcome sign at parking gate, dual colour, graphics
`and text, dynamically updateable, ethernet connectivity.
`Gardens Point, Brisbane. Photo taken: 2/10/2009 2:38pm............ 46
`
`Figure 3.18
`
`Red and green LED display on Newmarket Road, Windsor.
`Picture taken: 27/09/2009 6:19pm................................................. 47
`
`Figure 3.19
`
`FET voltage controlled current source for LED Circuit ................ 48
`
`Figure 3.20
`
`TPS61042 LED driver block diagram [33] ................................... 49
`
`Figure 3.21
`
`TPS61042 LED driver typical application diagram [33] .............. 49
`
`Figure 3.22
`
`Bit Angle Modulation (BAM) example ........................................ 51
`
`Figure 3.23
`
`Internal block diagram of the A6281 device ................................. 53
`
`Figure 3.24
`
`Internal Allegro A6281 block diagram [45] .................................. 54
`
`Figure 3.25
`
`A6281 chain for multiple connected LEDs ................................... 54
`
`Figure 3.26
`
`Figure 3.27
`
`Figure 3.28
`
`span
`life
`rated
`survival vs. percent of
`Percent
`Phillips Semiconductor [46] .......................................................... 56
`
`Normalised light output over 6000 operation hours for a
`Phillips Luxeon K2 LED [46] ....................................................... 57
`
`Increase in efficiency due to thin-film technology 1960-
`2009[47] ........................................................................................ 58
`
`Figure 4.1
`
`Graphical steradian definition [50] ................................................ 61
`
`Figure 4.2
`
`OOS T676 far field display pattern [25]........................................ 63
`
`Figure 4.3
`
`Normalised emitter pattern overlayed with cosine function;
`lambertian nature of surface LED emitters ................................... 63
`
`Figure 4.4
`
`Far field distribution pattern from COTCO/CREE [52]................ 64
`
`Figure 4.5
`
`Visualisation of FFDP of COTCO/CREE Screen Master
`LED lens family ............................................................................ 65
`
`Figure 4.6
`
`Luminance area and intensity definitions ...................................... 66
`
`Figure 4.7
`
`Luminance of two different surfaces from the same point
`source, in the same solid angle ...................................................... 67
`
`Figure 4.8
`
`Illuminance of a surface at distance D .......................................... 68
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`Figure 4.9
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`Figure 4.10
`
`Difference in Solid Angle and ultimately illuminance due to
`increasing distance ......................................................................... 68
`
`Efficiency and luminous intensity for common LEDs and
`manufacturers ................................................................................ 71
`
`Figure 4.11
`
`Spectrum of visible light annotated from 400-700nm[58] ............ 75
`
`Figure 4.12
`
`Sensitivity diagram for the three types of cone receptors
`(S,M & L), plus rods [61] .............................................................. 75
`
`Figure 4.13
`
`Normalised cone sensitivity diagram [62] [59] ............................. 75
`
`Figure 4.14
`
`3D plot of normalised activation curves [58] ................................ 77
`
`Figure 4.15
`
`Figure 4.16
`
`Figure 4.17
`
`Figure 4.18
`
`Chromaticity surface defined by removing the effect of
`intensity on colour [58] .................................................................. 78
`
`Tri-linear mixing (Maxwell) triangle [58] ..................................... 79
`
`CIE 1931 Chromaticity diagram with annotations [64] [65] ......... 80
`
`CIE 1931 and 1978 Colour matching functions (cid:1876), (cid:1877) and (cid:1878).
`Note that (cid:1877) is intentionally identical to the intensity
`
`response, labelled V((cid:79)), and that the currently valid plot is
`the 1931 model. For full data please see Appendix T:
`Colour Matching Functions Data[66][67] . ................................... 81
`
`Figure 4.19
`
`Chromaticity diagram with x = 0.306 and y = 0.338 plotted ......... 83
`
`Figure 4.20
`
`Figure 4.21
`
`Figure 4.22
`
`1931 Chromaticity diagram with line from 565nm to 420nm
`according to 1931 colour matching functions see Appendix
`T: Colour Matching Functions Data for the table of values
`for this graph .................................................................................. 84
`
`Dual colour LED sign, Brisbane Patios Office, Newmarket
`Road, Windsor ............................................................................... 85
`
`Close up of LED display at Brisbane Patios showing only
`red and green LEDs utilised to create yellow on the left
`hand side of the picture, and the singularly lit luminary,
`green, on the right. Picture taken: 28/09/2009 11:08am ................ 86
`
`Figure 4.23
`
`Different colour working profiles for common spaces[69] ........... 87
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`Figure 4.24
`
`Figure 4.25
`
`Perceptual and colorimetric colour mapping functions from
`large to small gamut [70] ............................................................... 89
`
`Gamut for NTSC, RGB LED Backlit LCD display, CCFL
`Backlit LCD and White LED Backlit LCD[71] ............................ 90
`
`Figure 4.26
`
`Red spectra comparison LED vs lamp with gel [75] ..................... 91
`
`Figure 4.27
`
`ETC Selador VIVID range[76] ..................................................... 92
`
`Figure 4.28
`
`Selador gamut compared to conventional RGB luminary
`gamut ............................................................................................. 93
`
`Figure 5.1
`
`Figure 5.2
`
`Figure 5.3
`
`Figure 6.1
`
`Figure 6.2
`
`Illustration of display physical terminology for use with the
`LAADtech display ......................................................................... 97
`
`Functional component layout for Prototype 1 of the
`LAADtech display ......................................................................... 98
`
`the
`Completed prototype 1(demonstration display) of
`LAADtech technology................................................................. 102
`Stealth display, 31st Oct 2007, only utilised for low
`resolution, high contrast backdrops of solid colour..................... 104
`
`Stealth display showing support points and ‘sag’ between
`the supports. ................................................................................. 105
`
`Figure 6.3
`
`6x Lighthouse 20mm display modules, one dead pixel. ............. 105
`
`Figure 6.4
`
`20mm Lighthouse display module close up ................................ 107
`
`Figure 6.5
`
`Pixel pitch of a 20mm Light House module ................................ 108
`
`Figure 6.6
`
`Figure 6.7
`
`Figure 6.8
`
`20mm Lighthouse module showing white lines for 20mm
`real pitch, and blue lines showing ½, or 10mm virtual pitch ...... 109
`
`Density vs intensity for selected OSRAM LEDs that
`perform as close as possible to the full dynamic range ............... 113
`
`Standard resolution and high resolution mode displaying
`two frames of a white line moving from right left across the
`display.......................................................................................... 115
`
`Figure 6.9
`
`Pattern forming for LED layout .................................................. 116
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`Figure 6.10
`
`Figure 6.11
`
`Figure 6.12
`
`Figure 6.13
`
`Figure 6.14
`
`Figure 6.15
`
`Figure 6.16
`
`Figure 6.17
`
`Rotating tube arrangement to remove the effect of LED
`arrangement on colour fringing ................................................... 116
`
`20mm full scale prototype (Left) and 20mm v10 Lighthouse
`display (Right) ............................................................................. 117
`
`Demonstration display with triangular pixel configuration
`and vertical pixel boundary crossing two similarly signalled
`red LEDs ...................................................................................... 118
`
`Full scale prototype with white, screen generated text, on
`black background ......................................................................... 119
`
`Construction of white text on black background using pixel
`arrangement and colour aliasing filter specific for this pixel
`layout and display ........................................................................ 120
`
`Oval Through Hole LEDs protruding through plastic facia
`under 4mm ‘sun shades’ .............................................................. 122
`
`Florescent lights reflected in the gloss acrylic finish of the
`demonstration display tubes ........................................................ 123
`
`A digital VMS display impossible to read in the morning
`sun due to a clear matt finished front........................................... 124
`
`Figure 6.18
`
`Membrane print specifications .................................................... 125
`
`Clear, black, matt and gloss finishes of the membrane when
`applied to the display, unlit .......................................................... 125
`
`LED shading due to creep in the black printing of the
`membrane panels. 4 columns appear on the display,
`distinguished by lines of discontinuous intensity. Photo
`taken: 13/01/2009 7:19pm ........................................................... 127
`
`LED shading due to creep in membrane printing. Final
`column distinction not visible due to changing viewing
`angle of the camera as the focus comes closer to the lens.
`The far column however is vividly apparent. Photo taken:
`13/01/2009 7:12pm ...................................................................... 127
`
`Figure 6.19
`
`Figure 6.20
`
`Figure 6.21
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`Figure 6.22
`
`Figure 6.23
`
`Figure 6.24
`
`Figure 6.25
`
`Figure 6.26
`
`Figure 6.27
`
`Figure 6.28
`
`The effect of the shadow due to creep in the membrane is
`not visible when viewed perpendicular to the face of the
`display.......................................................................................... 128
`
`Gloss finished segments reflect all surrounding light,
`however only at one angle ........................................................... 128
`
`Large (1-2mm) variance in length of tube due to end cap
`variability ..................................................................................... 130
`
`juxtaposed
`two panels
`Screen configured at 40mm,
`horizontally with mis-alignment and resulting gap due to
`poor tolerance in end cap placement ........................................... 130
`
`Low contrast, low saturation image as a direct translation
`from DVI data to PWM data. Note that the display was still
`being tested at this stage and blue panels, pixels out and
`tubes malfunctioning are not part of the visual assessment ........ 132
`
`Folsom visual processor connected to display Master
`Controller ..................................................................................... 133
`
`Contrast and gamma adjustment of display by Folsom
`processor ...................................................................................... 133
`
`Figure 7.1
`
`Relative efficiency and power consumption vs. intensity ........... 140
`
`Figure 7.2
`
`Figure 7.3
`
`Figure 7.4
`
`Figure 7.5
`
`Figure 7.6
`
`Figure 7.7
`
`Graph of 1, 2 and 3 green LEDs of different base intensities
`operating at 5000nits ................................................................... 142
`
`Maximum LED voltage, and minimum driver voltage used
`for minimum rail voltage calculation .......................................... 144
`
`Efficiency vs. output current for 3V3 and 5V A8498 3A
`converters .................................................................................... 148
`
`Modified 3V3 voltage converter efficiency vs. output
`current for multiple input voltages .............................................. 149
`
`Maximum efficiency (within 500mA range) vs.input voltage
`for the modified 3V3 converter ................................................... 150
`
`Combined efficiency of DC-DC supplies and cable vs. input
`voltage for various display power ............................................... 152
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`Figure 7.8
`
`Figure 7.9
`
`Combined efficiency of DC-DC supplies and cable vs .input
`voltage for various cable resistances ........................................... 153
`
`Initial 3V3 switching regulator design around the A8498
`buck controller ............................................................................. 155
`
`Figure 7.10
`
`Initial 5V switching regulator design around the A8498
`buck controller ............................................................................. 156
`
`Figure 7.11 3V3 Voltage converter efficiency vs. output current for multiple
`input voltages ............................................................................... 156
`
`Figure 7.12
`
`3V3 Ripple at 250mA with 10uH Inductor, RTSET = 100k,
`and Cout = 20uF, 48V input voltage ........................................... 157
`
`Figure 7.13
`
`Minimum on-time violation for low values of RTSET [87] ....... 157
`
`Modified 3V3 regulator at 610mA output, 50uH inductor,
`250uF output capacitance, 67k7 RTSET, 48V input ................... 158
`
`Modified 3V3 regulator at 617mA output, 50uH inductor,
`250uF output capacitance, 67k7 RTSET, 8.08V input ................ 159
`
`LEXAN SLX Tube profile showing PCB position and
`orientation .................................................................................... 164
`
`Calculated averaged thermal conductivity constant for a
`theoretical thermally homogeneous material ............................... 168
`
`Density and thermal conductivity constant for common
`materials [90] ............................................................................... 171
`
`Ratio of thermal conductivity constant to density for
`common materials ........................................................................ 172
`
`for non-electrically conductive
`Thermal conductivity
`materials [90] ............................................................................... 175
`
`transfer materials
`thermal
`Thermal conductivity of
`compared to air [91][90][92] ....................................................... 176
`
`Idealised aluminium extrusion with VO Soft Gap Pad
`coupling material installed ........................................................... 177
`
`Figure 7.14
`
`Figure 7.15
`
`Figure 8.1
`
`Figure 8.2
`
`Figure 8.3
`
`Figure 8.4
`
`Figure 8.5
`
`Figure 8.6
`
`Figure 8.7
`
`xiv
`
`IPR2020-01176 Page 00017
`
`

`

`Figure 8.8
`
`Figure 8.9
`
`Figure 8.10
`
`Figure 8.11
`
`Figure 8.12
`
`Figure 8.13
`
`Figure 8.14
`
`Figure 8.15
`
`Identification of thermal