1. April 15, 2017
LED BLU
Driving and Challenge
Q4, 2010
Allen Zhang

2. 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

3. TV Products Innovations
Display
Internet
Connectivity
TV Products Innovations
Human
Interface
LED
Backlight
LED backlight is very hot

4. LED Type Current Capability Color Forward voltage depends on color
Standard LED - drive current <50mA
High current LED - drive current mA
High power LED - drive current mA+
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

5. 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

6. 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

7. Local Dimming of TV LED BLU

8. Wide Color Gamut
NTSC cover
CCFL ~78%,
WLED ~80%,
RGB LED >110%)

9. 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

10. 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, Q2Kick 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

11. LED Driving Topology-NB
15” panel for example
6 strings, 10 LED per 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

12. LED Driving Topology-MNT
24” panel for example (1)
12 strings, 15 LED per 20mA
Vout ~50V, Pout ~12W
24” panel for example (2)
12 strings, 15 LED per 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

13. 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

14. ｝premium 28% ｝premium 41% ｝premium 61% ｝premium 43%
LED vs. CCFL Cost Comparison
Q3, 2010
｝premium 28%
｝premium 41%
｝premium 61%
｝premium 43%
$USD

15. LED TV Market Share Growth
Source: Display Search

16. 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

17. 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

18. 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

19. LED TV Power Optimize Reduce DC/DC Booster（Cost）
Current Solution
Reduce DC/DC Booster（Cost）
Efficiency improvement
Optimized Solution

20. On-Bright LED TV Total Solution
Headroom voltage feedback for efficiency and thermal improvement

21. 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。