Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Instructor: Tsorng Juu ( Peter), Liang
(梁
梁 從 主)
Professor
Dept. of Electrical Engineering
National Cheng-Kung University
Email：
：tjliang@mail.ncku.edu.tw
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■
Contents
◎ Background
Lighting terms
Fluorescent lamp and ballasts
High intensity discharge (HID) lamps
and ballasts
◎ Light emitting diodes (LEDs) and drive
circuits
2
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
◎ Background
Human life is changed by the invention of the light sources
Living quality can be improved by using appropriate lighting
sources
⇒Ambience, visibility, color rendering….
Lighting consumes more than 20% of total electrical power
consumption in the developed countries
(Usually, lighting consumes 30~50% of the energy cost of a
building)
Shortage of energy resources
⇒ Energy saving has become the most concern in the world.
Criterion of energy saving in lighting
⇒ Provide adequate visibility with quality illuminance and
minimum power consumption
3
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Lighting Terms
♦Luminous flux, F: The time rate of flow of light
• Unit: Lumen, lm
♦ Luminous intensity, I: The luminous intensity of a light in a specified
direction
• Unit: I, Candela, [Cd ≡ Luminous flux/Solid angle=Φ
Φ/Ω
Ω Cd]
♦ Illuminance, E : The luminous flux per unit area.
• Unit：
：Lux (Lux ≡ Lumen/m2)
♦ Brightness, B: The total lumens actually leaving the surface of light
source per unit area
• Unit ：Nt (Nt ≡Cd/m2)
♦ Luminous efficacy: The quotient of the total luminous flux emitted
by the total lamp power input
• Efficacy ≡ Lumen/ Power, lm/W
4
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Lighting Terms (Cont.)
♦ Radiation: The emission of energy in the form of electromagnetic waves from
all body
♦ Blackbody: A totally absorbing body (which reflects no radiation)
• A blackbody radiator absorbs all of the radiant energy reaching it,
transmitting and reflecting none
♦ Color Temperature (CT): The absolute temperature of a blackbody radiator
having a chromaticity equal to that of the light source
• Correlated color temperature (CCT): The absolute temperature of a
blackbody whose chromaticity most nearly resembles that of the light source
• Warm-white fluorescents (2700 K) ⇒ Suitable for residential lighting
• Cool-white fluorescents (4100 K) ⇒ Suitable for office lighting
♦ Color Rendering Index (CRI): The CRI of a light source is a measure of the
shift in chromaticity of an object when it is lighted by the source as compared
to being lighted by a reference source of comparable color temperature
5
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Lighting Electric Norms
♦ Input Voltage Range:
• Universal voltage range: 90~264 V; 108 V~305 V
♦ Limitation for current harmonics: IEC61000-3-2 Class C
• High current harmonic will cause low power factor
♦ EMI Regulation:
• CISPR15 (International Special Committee for Radio Interference)
1 T
∫0 Vac i acdt
Re al Power ( P )
T
=
♦ Power Factor, PF: PF ≡
Apparent Power(S)
Vrms ⋅ I rms
♦ Lamp Current Crest Factor, CF ) - CF ≡
♦ Protections:
• Over current protection
• Short circuit protection
• No-lamp protection
6
I lamp, peak
I lamp, rms
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Blackbody radiation curve
7
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
The color temperature of various light sources
晴朗藍
晴朗藍天 12,000 ~ 15,000 K
日蔭下 10,000 K
藍天白雲
陰天 6,500 ~ 7,500 K
天白雲 8,000 ~ 10,000 K
日光型螢
日光 5,500 K
日光型螢光燈 6,500 K
電子閃光燈5,500 K
閃光燈泡 4,200 ~ 5,000 K
早晨或下午陽
早晨或下午陽光 4,000 ~ 5,000 K 白色冷調螢
白色冷調螢光
調螢光燈4,500 K
白色暖調螢
攝影棚燈光
白色暖調螢光
調螢光燈3,500 K
攝影棚燈光 3,200 ~ 3400 K
石英燈
鎢絲燈
石英燈 3,300 K
鎢絲燈泡 2,700 ~ 3,200 K
黎明、
燭光1900 K
黎明、黄昏 2,000 ~ 3,000 K
8
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Historical perspective on light sources
Source：OSRAM
9
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
◎ Worldwide power supply market for selected applications
■ Eight opportunities for growth in 2009~2010.
(millions of $)
2008
2009
2010
2008-2009 CAGR
2009-2010 CAGR
Signage (AC-DC)
1,344
1,445
1,581
7.5%
9.4%
CFLs
4,118
4,604
5,697
11.8%
23.7%
LEDs/General Illumination
22
31
49
40.7%
58.1%
Vehicle Electrification
374
381
400
2.0%
5.0%
PV Inverter
3294
3,716
4,267
12.8%
14.8%
$9,152
$10,177
$11,994
11.2%
17.9%
Signage (LED Drivers)
873
1,093
1,781
25.2%
62.9%
Smart Meters
11
11
12
4.5%
9.0%
Building Automation
5
5
6
10.0%
20.0%
$888
$1,109
$1,799
24.9%
62.2%
$10,040
$11,286
$13,793
12.4%
22.2%
MODULES
TOTAL
ICs
TOTAL
GRAND TOTAL
Note: CAGR: Compound Annual Growth Rate.
Source：Darnell Group,2009/3; Power Electronics Lab., NCKU.
10
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ Global power supply market , largest revenue opportunities in 2009 and 2010
♦ CFLs is the best module opportunity
(millions of $)
5,697
23.7%
6000
7 0 .0 %
6 0 .0 %
4,604
5000
11.8%
4118
3,716
12.8%
4000
4,267
14.8%
3294
5 0 .0 %
2008
4 0 .0 %
2010
3000
3 0 .0 %
2000
2009
1,581
1,445 9.4%
1344 7.5%
CAGR
2 0 .0 %
1000
31
22 40.7%
0
Si g n a g e (AC -D C )
CAGR
C FL s
49
58.1%
L ED s/Ge n e ra l
Il lu m i n a tio n
381
374 2.0%
400
5.0%
0 .0 %
Ve h i cl e El e ctri fica ti o n
Note: CFL: Compact Fluorescent Lamp; PV Inverter: Photovoltaic Inverter.
Source：Darnell Group,2009/3; Power Electronics Lab., NCKU.
11
1 0 .0 %
PV In ve rte r
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ Worldwide power ICs market (Including the following applications)
♦ LED driver ICs used in general signage, video signs and digital billboards
♦ Controller ICs used in smart meters
♦ Regulator ICs used in wireless network building automation
♦ The best IC dollar opportunity is LED drivers for signage (millions of $)
2000
70%
1,781
62.9%
1800
60%
1600
50%
1400
1000
2008
1,093
1200
25.2%
40% 2009
2010
873
30% CAGR
800
CAGR
600
20%
400
200
11
0
Signage(LED Drivers)
11
4.5%
12
9.0%
Smart Meters
5
6
5
10.0% 20.0%
10%
0%
Building Autom ation
Source：Darnell Group,2009/3; Power Electronics Lab., NCKU
12
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ Global electronic ballast market trends and forecasts
♦Global electronic ballast dollar market: CAGR(2007-2010) of 7.1%
(millions of $)
6,000
5,000
4,660
4,277
4,000
5,277
4,979
3,915
3,511
4,468
4,213
3,872
3,574
4,766
3,861
4,340
4,085
North American
3,213
Europe
3,000
Asia
Mid-Sourth American
Other
2,000
1,000
596
426
638
447
723
532
681
489
766
574
0
2006
2007
2008
2009
Source：Darnell Group,2005; Power Electronics Lab., NCKU
13
2010
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ Lighting fixtures market forecasting
Note: Linear Fluorescent (LFL); Incandescent/Halogen (INC/HAL) ; Compact Fluorescent (CFL)
High Intensity Discharge (HID); Light Emitting Diode (LED)
Tsorng-Juu, (Peter) Liang
Source: Strategies unlimited, cooper 2008.
14
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ White-LED package efficacy targets- Laboratory and Commercial
Note: 1. Cool-white efficacy: CRI=70 → 80, CCT = 4100-6500°°K
2. Warm-white efficacy: CRI>85, CCT =2800-3500°°K
Source: LED Technical Committee and the Department of Energy, Fall 2008
15
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
◎ Light sources
Incandescent bulb
Tungsten-halogen lamp
Flash light
Radiant energy lamp
Light Sources
Gas discharge lamp
(Arc discharge)
Ultra high pressure
Ultra high mercury lamp
Ultraviolet (UV) mercury lamp
High pressure
Mercury lamp
High pressure mercury lamp
Metal halide lamp
High pressure sodium
Xenon lamp
Low pressure
Fluorescent lamp
Low pressure sodium
Solid state lighting
Electromagnetic lamp (EL)
Light emitting diode (LED)
Coherent lighting
Laser
16
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Comparison of various light sources
Lamps
Fluorescent
LED
HID Lamp
(複金屬燈
複金屬燈)
複金屬燈
(螢光燈
螢光燈)
螢光燈
High pressure
sodium
(高壓鈉燈
高壓鈉燈)
高壓鈉燈
Low pressure
Sodium
(低壓鈉燈
低壓鈉燈)
低壓鈉燈
High pressure
Mercury
(水銀燈
水銀燈)
水銀燈
Incandescent
(白熾燈
白熾燈)
白熾燈
characteristic
Efficacy (lm/W)
90-110
40 ~80
80-120
62-140
150
15-60
3-23
CRI
(演色性
演色性)
演色性
70-90
Good
70 ~ 90
Good
70-95
Excellent
25
Poor
20
Poor
40-50
Fair
100
Excellent
Power Range
(W)
5-80
0.1 ~ 10
20-1500
35-1000
35-180
4-1000
5-1000
Life (Hours)
10000
60000
6000-9000
12000
12000
12000
1000-2000
Applications
Office, Shop,
Hospital,
Home,
LCD
backlight
LCD TV
backlight,
Traffic
sign,
Indicator,
Decorate
lighting
Mall,
Stadium
Excellent
Excellent
Good
Features
Factory,
Ware house,
Street lighting
Fair
17
Roadway,
Tunnels,
Canals,
Street
lighting
Fair
General
lighting in
factories,
garages,
No good
Home,
Restaurant,
Emergency
lighting
No good
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
♦ Incandescent lamp
• An incandescent lamp can be connected directly
with utility power with specified voltage range
• A ballast is required for Tungsten-halogen lamp
• Energy distribution- About 10% of energy is
available for visible radiation.
♦Schedule to exterminate
the incandescent lamp
• Ireland: 2009
• Australia: 2010
• Argentina: 2010
• Italy: 2010
• France: 2010
• UK: 2011
• Netherland: 2011
• Taiwan: 2012
• Canada: 2012
• Japan: 2012
• US: 2014
• China: 2017
18
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
♦ Types of tungsten halogen lamps
Source: http://www.atelierten.com/
19
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ Fluorescent lamps
◆ T means tubular in shape
• Tx = x/8 inch in diameter
• T8 = 8/8 inch in diameter
• T5 = 5/8 inch in diameter
◆ Compact Fluorescent Lamp (CFL)
• Twin-tube, Quad-tube, Triple tube
• 2D, Circular lamp
• BX = Biax lamp
CFL with electronic ballast
Source: http://www.atelierten.com/
20
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
♦ Energy distribution of a fluorescent lamp
- About 22% of total energy is available for visible radiation
21
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ Energy distribution of a cold cathode fluorescent lamp (CCFL)
- About 29.5% of total energy is available for visible radiation
22
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
♦ Fluorescent lamp
• Driving circuit design of fluorescent lamp
- Provide very high start-up voltage to ignite the FL (400 V~700 V)
- Provide appropriate current to drive FL during starting period
- Provide appropriate steady- state power (current) to FL
- Can be used to drive the different brands of FL ( Meet the same NSI
standard)
- Protections (lamp open protection, short circuit protection,..)
- Smaller size
- Reliable
- High power factor: Low input current harmonics - IEC61000-3-2 Class
- Low glow current
- High efficiency
- Low lamp current crest factor
- Meet EMI regulation: CISPR15 ( International Special Committee for Radio
Interference)
23
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
◎ Electronic ballast for fluorescent lamp
Circuit topologies for fluorescent lamp
♦ Passive PFC + Half-bridge dc-ac inverter
♦ Single stage electronic ballast
• Voltage-source charge-pump PFC electronic ballast
• Current-source charge-pump PFC electronic ballast
♦ Active PFC + Self-oscillating dc-ac inverter
• Boost PFC + Half-bridge self-oscillating inverter
• Boost PFC +Full-bridge self-oscillating inverter
♦ Active PFC + Half-bridge IC controlled dc-ac inverter
24
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
◎ Typical electronic ballast for fluorescent lamp
♦ Active PFC + IC controlled half-bridge dc-ac inverter
PFC stage
(Boost Converter)
Lboost
DC/AC resonant inverter
(Half-Bridge)
Dboost
Lr
Cr
S1
Vac
Lamp
Sboost
Cbus
S2
25
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
◎ Electronic ballast for cold cathode fluorescent lamp
Circuit topologies for CCFL
♦Three-stages electronic ballast
• Plamp＜150W ⇒ Active PFC + QR-Flyback converter + FB-Inverter
• Plamp＞150W ⇒ Active PFC + LLC converter + FB-Inverter
♦Liquid crystal display integrated power supply (LIPS)
• Active PFC + Half-bridge dc-ac inverter
• Active PFC + Full-bridge dc-ac inverter
♦Control schemes for full-bridge resonant inverter
• Phase-shifted controlled
26
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Typical electronic ballast for CCFL
♦ Phase-shifted controlled scheme for full-bridge resonant inverter
SGS,1
♦ Phase-shifted controlled
• S1 & S2 are complementary switches
(Dead time is needed)
• S3 & S4 are complementary switches
• VGS,4 and VGS1 are phase shifted by α
• Zero voltage switching
SGS,4
SGS,2
SGS,3
27
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
♦ Energy distribution of a 400 W metal halide lamp
• About 24.3% of total energy is available for visible radiation
28
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
♦ Energy distribution a 400W high pressure sodium lamp
• About 29.5% of energy is available for visible radiation
29
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Applications of HID lamps
♦ Outdoors:
Building, roadway, bridge, tunnel,
stadium, athletic field
♦ Indoors:
Household, factory, warehouse,
showcase, market, exhibition
hall
♦ Industries:
Head light for vehicle, projector,
high quality TV, PCB
manufacturing
30
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Technical specifications of electronic ballast for HID lamps
♦ Provide high igniting voltage ( 2kV~3.5 kV)
♦ Provide appropriate power during starting
Transient period: Current limit control
Steady state: Constant power control ( Negatively incremental impedance)
Note: 1. The lamp voltage may be increased by 50% due to ageing
2. The starting time of HPS and LPS is longer the metal halide lamp
♦ Universal utility ac input voltage ( 108~305V)
♦ High power factor( > 0.9)
♦ Drive various HID lamps with same NSI standard
♦ High efficiency( > 85%)
♦ Small size and reliable
♦ Over temperature protection, over current protection, no lamp protection
♦ Avoid acoustic resonance
Low frequency square waveform: 120 Hz~ 200 Hz
Very high frequency operation: ~ MHz
♦ Hot lamp re-strike: the HID lamp will be restarting in 30 minutes
31
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Typical three-stage electronic ballast for HID lamp
♦ Boost converter: Power factor correction
♦ Buck converter: Lamp power control
♦ Full-bridge inverter: Produce low frequency square-wave
to drive the lamp
♦ Igniter: Provides ignition voltage pulse to ignite lamp
Lamp Power Control Stage
PFC Stage
(Buck Converter)
(Boost Converter)
Lboost
Dboost
Lbuck
iLbuck
Sbuck
vac
Sboost
Cin
Cbus
Lamp Driving Stage
(Full-Bridge Inverter)
+
Vbus Dbuck
-
32
Cbuck
S1
+
Vobuck
S2
Ilamp Lamp
Igniter
S3
Tig
S4
+VlampSIDAC
Cig
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Two-stage electronic ballast for HID lamp
♦ SH1 and SH2 are operated in high switching frequency
♦ SL1 and SL2 are operated in low switching frequency
33
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ History of LED
฀
◆ LEDs have been widely applied for over 35 years
◆ For 25 years, LEDs are mainly used as small indicator lamps and
alphanumeric displays
฀ • Can not cover the full color spectrum (e.g. blue and green)
◆ High-brightness AlGaAs introduced in mid-1980s by HP and Stanley
Electric (red only)
◆ LED materials “revolution” occurred in the early-mid 1990s
◆ InGaAlP developed by HP and Toshiba produced high-brightness red,
orange, and yellow (ROY)
◆ InGaN developed by Nichia, Toyoda Gosei and Cree produced high
brightness blue, green and white (using blue + phosphor)
◆ These devices were fabricated with MOCVD (rather than LPE and VPE
used in conventional LEDs)
Source: Roland Haitz
34
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
◎ Light Emitting Diodes (LEDs)
■ Light emitting diode
◆ When an electrical charge is applied, light is generated from electronic
transitions and released as a photon
◆ A solid state light source SSL (semiconductor diode)
Source: GE, 2009
35
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Types and Packages of LED
♦ Illuminator (High Power)
♦ Indicator (Low Power)
Structure of a high-brightness LED
Structure of a 5mm type LED
Source: LumiledsTM
36
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ LED target segments
Source: GE, 2009
37
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
The applications of high brightness LED segments
Source: Strategies unlimited
38
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Halogen lamps replaced by LED lamp
◆ Halogen MR16 lamp can be replaced by a LED lamps
Halogen MR16 lamp
LED
20 ~ 25 Watt
4 Watt
Source：www.ushio.com
39
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Incandescent
(BR30) lamps replaced by LEDs
• LED lamps
Total power =948 W
• Incandescent BR30 lamps
Total power =5,135 W
♦Uniformity, Consistency & Brightness
Source：CREE, 2008
40
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
LED signboard
◆ A flexible and transparent signboard can be
designed with innovative LED lamps
source：www.topnanosys.com
41
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
LED modules for signage
Source：Link Power Smart Forum 2008.
42
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
General lighting with LEDs –Indoor applications
LED Candle
Source：Norex enterprises
Source：Link Power Smart Forum 2008
43
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Traffic lights with LEDs
♦ Low power consumption (≈ 10% of incandescent lamp)
♦ Longer life ( about 10 times longer than incandescent lamp)
←
44
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
HB LED in mobile applications
Next
7“LCD for Car GPS, portable DVD & Electronic picture frame
Source：EPISTAR corporation
45
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
LED for notebook applications
Source：EPISTAR corporation
46
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
LED for LCD monitor applications
114% NTSC
1,000:1 Contrast ratio
Source：EPISTAR corporation
47
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
LED for LCD TV applications
146% NTSC
10,000:1 Contrast ratio
105% NTSC
1,000,000:1 Contrast ratio
Source：EPISTAR corporation
48
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Structure of streetlight
Housing (including Heat Sink)
LED Lamp
Reflector
Power Supply
49
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ Generating of white LEDs
◆ RGB Multichip
• Good efficiency
• Poor light quality
• Low output packages
• Potential for color shift
◆ Blue chip + yellow phosphor
• Excellent efficacy in cool white
• Lower efficacy in warm white
• CRI varies, usually a trade off with efficacy
• Light mixed from two or more materials,
potential for color shift
◆ Violet chip + multi phosphor
• The best quality of light from LED
• Warm white packages (3000-4100K)
• Light emitted by single material hence
stable color
Source: Strategies unlimited
50
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
■ LED price/performance trends
♦ The light output of LED : Increased 20 times each decade
♦ The cost ($/lumen) of LED: Decreased 10 times each decade
Source: Roland Haitz and Lumileds
51
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Electrical characteristics of LED
♦ Relative light output vs. Tj
♦ Relative luminous vs. LED current
200
1.2
180
Green, Blue, White
140
Normalized Relative Luminous Flux
White
Red
Blue
Green
160
120
100
80
60
40
20
Red
1.0
0.8
0.6
0.4
0.2
0
-20
0
20
40
60
80
100
120
0
0
Junction Temperature, TJ ( C)
100
200
300
400
IF-Average Forward Current (mA)
52
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Output Voltage Changes when LED Current Changes
♦ 4% voltage change will cause 50% current change
(3.21 V/400 mA; 3.34 V/600 mA)
♦ 20o temp. variation will cause 100 mA current change
♦ Constant current control is preferred for LED
i-v curve of LED
53
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Thermal
resistance model of LED
• Thermal resistance is defined as the
ratio of temperature difference to the
corresponding power dissipation
• The overall RΘ
Θ Junction Ambient (JA) of a
LUXEON Power Light Source plus a heat
sink is defined in Equation 1
Source：Lumileds
54
Emitter Cut-Away
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Progress
of LED package technology
♦ Operating current of LED is increased from 20mA to 1A
♦ Thermal resistance is decreased form 360℃
℃/W to 6~10 ℃/W
Source: Material Research Lab., ITRI, Taiwan
55
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Driving LEDs by current limiting resistor
• Low cost
• Simple circuit
• Unstable current regulation ability
R
B1
.....
R
BN
Vdc
56
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Driving LEDs by commercial IC – charge pump driver
• Small volume, non-inductor, and easy design
• The maximum output voltage is limited (Twice the input voltage)
• Driving multiple LEDs in parallel ⇒ More driving ICs are required
57
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Driving LEDs by commercial IC – inductive driver
• High efficiency
• Wide range of output voltage
• Inductor is needed ⇒ large volume
58
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
LED drive converter circuit
♦ Passive PFC + Flyback converter
• Narrow-range input voltage
• Adequate PF
• Low cost & simple
59
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
LED drive converter circuit
♦ Single-stage flyback converter
• Narrow-range input voltage
• High PF
60
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
LED drive converter circuit
♦ Active PFC+ Flyback /(QR flyback) converter
• Wide-range input voltage
• High PF
61
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
◎ Quasi-resonant flybak converter- Turn on power switch at
zero voltage/low voltage
62
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
LED drive converter circuit
♦ Active PFC+ Half-bridge converter
• Wide-range input voltage
• High PF
• Suitable for higher power applications
63
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
AC LED
Source: US 7138770 B2, Nov. 21, 2006
64
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
AC LED and DC LED illumination application contrast
Lighting form
20W tungsten
filament lamp
5W DC LED
ITRI -5WAC LED
250 lm
250 lm
250 lm
12.5 lm/W
50 lm/W
50 lm/W
AC110V/180mA
DC3.5V/1.5mA
AC110V/50mA
Lamp Fixture
Efficiency (%)
60%
85%
85%
Power Factor
100%
30-70%
85-93%
Circuit Efficiency
100%
Circuit Cost
Low
High
Low
Thermal
Management
Assembly
None
Aluminum base
Hot Swap
Comparative items
Total Luminous
Flux (lm)
Lighting
Efficiency
Lighting
Efficiency (lm/W )
Input Power
Lamp
Fixture
Application
Fashion Design
Good
30-85%（Efficiency
decreasing by add a
constant current circuit)
No Good( Heat)
Source: Electronics & Optoelectronic Lab., ITRI, Taiwan
65
95%
Good
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Comparison among Traditional incandescent bulb, DC LED, AC LED
♦ Characteristics of AC LED
• No extra drive circuit is required
• Compact
• 5 ~10 W AC LED are available in the market
Source: Electronics & Optoelectronic Lab., ITRI, Taiwan.
66
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Challenge of LEDs applications
♦Cost - Higher cost than other light sources (HB white LED)
♦Lighting efficacy- Target efficacy for HB white LED is 120~200 lm/W
♦Thermal- 65~75% power dissipation on LED chip module
• High temperature ⇒ Low light output from LED
⇒ Low reliability of power supply
⇒ Low color stability
♦Glare- Light source appears to be excessively bright
• Glare can be created when contrast between two areas is severe
• Glare can cause a loss in visual acuity and eye fatigue and strain
♦Shadow- Shape and length of shadows dependent upon
• Intensity of a light source
• Angle of direction
• Distance from object
♦Electric characteristic variation of LEDs
• Parallel operation
• Series operation
67
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory
Opportunity and Challenge of Power Supply
Engineers in Solid State Lighting System
Lighting Your Life with High
Efficiency Lighting System
Tsorng-Juu, (Peter) Liang
National Cheng Kung University
Power Electronics Laboratory