April 15, 2017 LED BLU Driving and Challenge Q4, 2010 Allen Zhang
Outline LED to CCFL Replacement LED backlight benefits analysis CCFL/LED market share trend Small & Middle Size Driving Topology LED notebook/Netbook LED monitor Low-end display LED TV Driving Topology OB LED Driver Roadmap Q&A
TV Products Innovations Display Internet Connectivity TV Products Innovations Human Interface LED Backlight LED backlight is very hot
LED Type Current Capability Color Forward voltage depends on color Standard LED - drive current <50mA High current LED - drive current 50-150mA High power LED - drive current 150-1000mA+ Color White LEDs Red, Green and Blue LEDs (Combined white) White Light Forward voltage depends on color Red ~2V, Green ~3.5V, Blue/White ~3.5-4V
Benefits of LED Backlight Power saving (30~40% saving for 12~14” NB) Longer life time (+50,000 hrs vs. ~20,000hrs of CCFL) 0~100% wide dimming range (up to 20KHz PWM dimming, audio noise free) Low voltage driver reduces complexity power design Environmental friendly (CCFL contains Hg) Local dimming for power saving and higher CR (Large size direct type backlight only) Wide color gamut (NTSC, CCFL ~78%, WLED ~80%, RGB LED >110%) Light weight and thin profile
Power Saving of LED BLU Low drive voltage to ensure safety operation The relationship between LED intensity and drive current is liner Lower current is operated to perform the same brightness level that CCFL module Power saving of 30~50% of CCFL power consumption
Local Dimming of TV LED BLU
Wide Color Gamut NTSC cover CCFL ~78%, WLED ~80%, RGB LED >110%)
LED BLU Market Potential Application Advantage Challenge High NB PC Power Saving Light weight Thin profile Small cost premium None LCD TV Power Saving Dynamic BLU control Cost Reliability Huge LED Amount Thermal compensation LCD MNT Power Saving Thin profile Cost Input/output interface Low
LED BLU Market Share 2008 2009 2010 2011 Share Rate (NB) 21.90% 66.70% 89.40% 95.20% Share Rate (MNT) 0.30% 1.90% 18.90% 35.10% Share Rate (TV) 2.68% 21.26% 45.29% Samsung MP LED TV at 2009, Q2Kick off LED TV market Low cost Edge type become main stream Help to rise the share rate from CCFL Power saving features Easy to meet EPA5.0 Will break 50% share ~2012 Source: Display Search
LED Driving Topology-NB 15” panel for example 6 strings, 10 LED per string @ 20mA Vout ~33V, Pout ~4W OB3360 Features Build-in 60V MOSFET 8 string output With 60mA current capability per string 160K/320K/620K/1.2MHz frequency 0~100% wide range dimming 3% channel to channel current matching
LED Driving Topology-MNT 24” panel for example (1) 12 strings, 15 LED per string @ 20mA Vout ~50V, Pout ~12W 24” panel for example (2) 12 strings, 15 LED per string @ 20mA Vout ~33V, Pout ~4W parallel connection to support larger current application OB3362 Features 12 string output With 60mA current capability per string 150~500kHz frequency 0~100% wide range dimming 3% channel to channel current matching
LED Driving Topology-Low End Display 26” panel for example (2) Single string, 400mA Vout ~40V, Pout ~16W OB337X 0.2V reference benefits efficiency Internal burst and external PWM dimming Output over voltage protection OB3372:Boost,DIP8, built in 60V MOSFET OB3370N:Boost, SOP8, Controller OB3370P:Buck, SOP8, Controller
｝premium 28% ｝premium 41% ｝premium 61% ｝premium 43% LED vs. CCFL Cost Comparison Q3, 2010 ｝premium 28% ｝premium 41% ｝premium 61% ｝premium 43% $USD
LED TV Market Share Growth Source: Display Search
Direct type with Local dimming Direct type without Local dimming LED Backlight for Large Size TV Panel Direct Backlight: Better emission Allowing independently dimming block by block Edge Backlight: Allowing slim design Fewer LED number and lower cost High Performance Slim Profile Direct type with Local dimming Direct type without Local dimming Edge type backlight RGB LED / White LED White LED RGB & Local dimming has power saving and high-CR feature High-end use Edge type solution has low cost feature Main stream
LED TV Cost Down Trend 2008 2009 2010 2011 structure Direct type Edge type Advanced edge type Advanced edge type 40 inch LED TV 2008 2009 2010 2011 structure Direct type Edge type #LED 960 576 400 176
LED TV Driving Topology 42” panel for example 4 strings 150mA per string Vout ~150V, Pout ~90W OB3376 Dual channel boost controller 150/300kHz switching frequency Multi chip sync. Cost effective
LED TV Power Optimize Reduce DC/DC Booster（Cost） Current Solution Reduce DC/DC Booster（Cost） Efficiency improvement Optimized Solution
On-Bright LED TV Total Solution Headroom voltage feedback for efficiency and thermal improvement
作者简介： 张昌山先生毕业于西南交通大学电子工程系，长期以来一直致力于背光驱动市场的产品规划及技术研究，张先生于2005年正式加入昂宝电子（上海）有限公司，期间一直担任系统部总监，全权负责公司电管理芯片之应用团队及管理。 张昌山先生在相关领域拥有丰富的实际应用经验，在LED照明驱动、背光驱动均有自己独到的见解，张先生在该领域还拥有多项国内外专利。