Remote LCD Buffer, Controller and Bridge An Engineering and Business Case for today’s mobile communication terminal Shri S...
Background & Context <ul><li>Market Trend </li></ul><ul><ul><li>Shift to High Resolution: QVGA    WQVGA    WVGA </li></u...
Challenges posed by trends
Challenges – Power Consumption <ul><ul><li>Power Consumption due to high speed refresh of large display resolutions </li><...
Challenges – Data Throughput <ul><li>30(Video codec rate)-60(Display refresh cycle) fps </li></ul><ul><li>WVGA = 800x480 p...
Critical to overcoming these challenges
Critical to overcoming these challenges – Buffer Memory  Host CPU (Cellular BB) Application Engine Frame Buffer Memory Hos...
Comparing the two cases! ~ refresh cycle Host CPU (Cellular BB) Application Engine Frame Buffer Memory Host CPU (Cellular ...
What difference does a Frame Buffer IC make? <ul><li>The main issue </li></ul><ul><ul><li>Application Engine does Video de...
The Need for Display Buffer WVGA  Display BB w/  QVGA RAM  (for video and screen saver) no RAM!! WVGA Buffer BB Cost  Powe...
Business case? <ul><li>Using LCD Frame Buffer IC brings into focus certain tangible financial benefits and some intangible...
LCD Buffer Basic Configuration (actual product) <ul><li>Video Data is input as Serial (LVDS) and Output as Parallel (RGB) ...
In Summary <ul><li>There is a trend toward higher resolution displays in mobile phones </li></ul><ul><ul><li>While these t...
Something to think about… <ul><li>LCD Buffer IC may not be suitable for lower resolution displays since the economics may ...
 
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SID 2007 (San Diego, CA) Presentation

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This was the presentation I gave at SID 2007 event in San Diego, CA (October 2007)

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SID 2007 (San Diego, CA) Presentation

  1. 1. Remote LCD Buffer, Controller and Bridge An Engineering and Business Case for today’s mobile communication terminal Shri Sundaram, Toshiba America Electronic Components, Inc. Oct 2/3, 2007
  2. 2. Background & Context <ul><li>Market Trend </li></ul><ul><ul><li>Shift to High Resolution: QVGA  WQVGA  WVGA </li></ul></ul><ul><ul><li>Several types of LCD mounting (mechanical): Cycloid, Slider, Clamshell etc. </li></ul></ul><ul><li>Challenges posed by these trends </li></ul><ul><ul><li>Power Consumption due to high speed refresh of large display resolutions </li></ul></ul><ul><ul><li>Data throughput (from Baseband or Application Processor to LCD Module) </li></ul></ul><ul><li>Critical to overcoming these challenges </li></ul><ul><ul><li>High-Speed and Large data transferability </li></ul></ul><ul><ul><li>Serial Data transferability with a fewest signal lines possible </li></ul></ul><ul><ul><li>Low EMI by, perhaps, Low amplitude signaling </li></ul></ul><ul><ul><li>High Capacity Buffer Memory is necessary </li></ul></ul>
  3. 3. Challenges posed by trends
  4. 4. Challenges – Power Consumption <ul><ul><li>Power Consumption due to high speed refresh of large display resolutions </li></ul></ul><ul><ul><li>Data throughput (from Baseband or Application Processor to LCD Module) </li></ul></ul>~LCD refresh cycle Host CPU (Cellular BB) Application Engine Frame Buffer Memory Host CPU (Cellular BB) Application Engine Frame Buffer Memory Bridge LCDD RGB I/F LVDS I/F LVDS I/F LCDD WVGA WVGA Type 2 Type 1
  5. 5. Challenges – Data Throughput <ul><li>30(Video codec rate)-60(Display refresh cycle) fps </li></ul><ul><li>WVGA = 800x480 pixels = 384,000 pixels </li></ul><ul><li>18-24 bits per pixel </li></ul><ul><li>--------------------------------------------------------------------------------------------------- </li></ul><ul><li>Adds up to: </li></ul><ul><li>207.36 Mbps – 552.96 Mbps!!! </li></ul><ul><ul><li>Power Consumption due to high speed refresh of large display resolutions </li></ul></ul><ul><ul><li>Data throughput (from Baseband or Application Processor to LCD Module) </li></ul></ul>
  6. 6. Critical to overcoming these challenges
  7. 7. Critical to overcoming these challenges – Buffer Memory Host CPU (Cellular BB) Application Engine Frame Buffer Memory Host CPU (Cellular BB) Application Engine Frame Buffer Memory LCD Buffer LCDD RGB I/F LVDS I/F LVS I/F LCDD LCD Buffer LVDS I/F ~ refresh cycle 15fps/30fps video codec ~ refresh cycle 15fps/30fps video codec WVGA WVGA
  8. 8. Comparing the two cases! ~ refresh cycle Host CPU (Cellular BB) Application Engine Frame Buffer Memory Host CPU (Cellular BB) Application Engine Frame Buffer Memory Bridge LCDD RGB I/F LVDS I/F LVDS I/F LCDD WVGA WVGA Type 2 Type 1 Host CPU (Cellular BB) Application Engine Frame Buffer Memory Host CPU (Cellular BB) Application Engine Frame Buffer Memory LCD Buffer LCDD RGB I/F LVDS I/F LVS I/F LCDD LCD Buffer LVDS I/F ~ refresh cycle 15fps/30fps video codec ~ refresh cycle 15fps/30fps video codec WVGA WVGA Main Difference
  9. 9. What difference does a Frame Buffer IC make? <ul><li>The main issue </li></ul><ul><ul><li>Application Engine does Video decoding and LCD controlling functions </li></ul></ul><ul><ul><li>Often, memory on Application Engine is non-dedicated memory for Video operation and Frame buffering </li></ul></ul><ul><ul><li>Even for a simple image refresh (@30fps), Application Engine cannot go to sleep mode! </li></ul></ul><ul><li>The concern is </li></ul><ul><ul><li>Dependence on the memory usage (size of image) PLUS the need to refresh main LCD and/or sub-LCD makes this system consume high-power </li></ul></ul>
  10. 10. The Need for Display Buffer WVGA Display BB w/ QVGA RAM (for video and screen saver) no RAM!! WVGA Buffer BB Cost Power/ Performance RAM WVGA Display (Performance) (Cost???)
  11. 11. Business case? <ul><li>Using LCD Frame Buffer IC brings into focus certain tangible financial benefits and some intangible financial benefits. </li></ul><ul><li>Financial Benefits </li></ul><ul><ul><li>No need for a frame buffer on the LCD Driver (use of so called “Dumb Displays”) </li></ul></ul><ul><ul><li>No need for frame buffer on the Application Processor </li></ul></ul><ul><li>Intangible Benefits </li></ul><ul><ul><li>Lower power consumption means longer battery life! </li></ul></ul><ul><ul><li>Certain “smartness” can be configured into the LCD Buffer IC such as… </li></ul></ul><ul><ul><ul><li>Scaling (or) doubling function </li></ul></ul></ul><ul><ul><ul><li>Partial Writing </li></ul></ul></ul><ul><ul><ul><li>Image Inversion </li></ul></ul></ul><ul><ul><ul><li>Rendering 18 bit data in pseudo 24 bit format </li></ul></ul></ul><ul><ul><ul><li>Etc… </li></ul></ul></ul>
  12. 12. LCD Buffer Basic Configuration (actual product) <ul><li>Video Data is input as Serial (LVDS) and Output as Parallel (RGB) </li></ul>LCD Buffer Memory for VGA/WVGA PLL LCD Controller Core Logic LVDS I/F 30fps ~Refresh rate RGB Data VSYNC HSYNC Dot Clock Reference Clock LVDS
  13. 13. In Summary <ul><li>There is a trend toward higher resolution displays in mobile phones </li></ul><ul><ul><li>While these trends bring fascinating applications to consumers, it does makes the job of system engineers difficult. </li></ul></ul><ul><li>Two major problems </li></ul><ul><ul><li>Power consumption </li></ul></ul><ul><ul><li>Data throughput </li></ul></ul><ul><li>LCD Buffer IC is solution to these problems </li></ul>
  14. 14. Something to think about… <ul><li>LCD Buffer IC may not be suitable for lower resolution displays since the economics may weigh in favor of LCD Driver with integrated RAM </li></ul><ul><li>However, it may be wise to consider including LCD Buffer ICs in the platform to allow for future upgrades to higher resolution designs </li></ul>

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