11 W Triac Dimmable PAR30 LED Driver

AND8463/D
11 Watt TRIAC Dimmable
PAR30 LED Lamp Driver
Prepared by: Jim Young
ON Semiconductor
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APPLICATION NOTE
well as electrical requirements for integrated driver within
the bulb. One of the key requirements which applies to all
bulbs that draw more than 5 watts of power is that the power
factor be ≥0.70 and the driver must meet specific FCC EMI
requirements.
While not mandated, dimming is a key end market
requirement for many uses and is one of the reasons that
CFL bulbs have not had broader acceptance in this bulb style
where halogen and traditional incandescent are the norm.
The standard requires that for those bulbs that are line
dimmable via a wall dimmer, either leading edge (TRIAC)
or trailing edge (transistor based), that the vendor clearly
label whether the bulb is dimmable or not and provide a list
of compliant dimmers that work with the LED bulb. One
other consideration, since LEDs require a heatsink to
remove the heat from the LED, the driver should normally
be galvanically isolated.
Parabolic Aluminized Reflector (PAR) lamps are one of
the most popular bulb types for downlighting, retail, and
spot light applications. They range in size from PAR16 to
PAR64. The number indicates the diameter in 1/8” units so
a PAR30 lamp would have a diameter of 3.75” (9 cm). Other
variants of these directional lamps include R and BR styles.
Given that the light pattern of these types of bulbs is
directional in nature, they are ideal candidates for LED light
sources. In addition, since PAR lamps are offered in various
beam widths, changing secondary optics on the LEDs can
result in a range of product types from spot to flood.
The US ENERGY STARt program has just completed
their standard for Integral LED bulbs which will go into
effect August 31, 2010. These specifications are
comprehensive and include items such as minimum light
output requirements, efficacy, acceptable correlated color
temperatures, dimming considerations, and warrantee as
Figure 1. PAR30 LED and Incandescent Lamps
© Semiconductor Components Industries, LLC, 2010
July, 2010 − Rev. 1
1
Publication Order Number:
AND8463/D
AND8463/D
Details for a 115 and a 230 V ac input version are presented
in this Application Note. Here are the design goals:
• 115 V Lamp Input Voltage: 90 – 135 V ac
Power Factor: >0.9
Input current THD: <20%
• 230 V Lamp Input Voltage: 180 - 265 V ac
IEC 61000−3−2 Class C compliant
• LED power: 11 watts
• LED current: 450 mA
• LED current accuracy: +/- 5%
• LED voltage: 21 – 27 V dc
• Efficiency: >82%
• Compatible with TRIAC and Electronic Low Voltage
Dimmers
• Compliance with FCC Class B conducted emissions
The circuit design, component selection, and layout of the
reference board were based on general safety guidelines
although the design has not been submitted to a safety
ratings agency for formal review.
A printed circuit board outline extending from the bottom
of the E27 base to the LED mounting plate was chosen. The
irregular outline matches the interior space of the selected
heatsink and base assembly. Component placement and
circuit routing is critical to provide adequate voltage
spacing. The PCB and lamp assembly is shown in Figures 2,
3, and 4 below:
This Application Note details how the NCL30000 single
stage power factor corrected isolated flyback controller can
be used to implement a complete power conversion solution.
This design shown in Figure 1 above is adapted from the ON
Semiconductor NCL30000 LED driver demonstration
board with a range of changes to optimize the design for a
well defined LED load. A commercially available LED
heatsink assembly and E27 Edison base housing were used.
CREE’s MPL-EZW LED module was selected as the light
engine. The LED module electrical connections and
mechanical securement are made with the Tyco Electronics
TE solderless LED socket 2106946-2. This connector
provides a clean and efficient interface to the LED. This
multi-LED module has 24 LEDs arranged in 3 strings of 8.
The LEDs are configured in a series-parallel arrangement
with a nominal drive current of 450 mA (150 mA per string).
Other LEDs can be used as well but the ultimate limitation
to the PAR form factor is the thermal heatsinking of the
housing and the expected end application environment.
The size of the PAR30 envelope is well defined and the
primary objective in this design is to provide as much power
as possible to the LEDs while achieving high energy
conversion efficiency.
Initial Design
Space inside the housing is limited and the general
solution presented in the NCL30000LED1GEVB
demonstration board will be modified towards the specific
requirements of an 11 watt TRIAC dimmable LED lamp.
Figure 2.
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AND8463/D
Figure 3.
Figure 4.
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AND8463/D
Detailed Design
applications whereas the 230 V application requires an
800 V FET. Likewise, a 100 V Schottky rectifier is
appropriate for 115 V applications and a 200 V device was
chosen for 230 V lamps.
A turns ratio of 5.3 to 1 will function well with both input
ranges. The minimum operating frequency will change
depending on the input voltage. Frequency is sufficiently
low for the EMI filter to accommodate either range. Safety
isolation requires triple insulated wire where 21 turns of #26
wire fills one layer. Splitting the primary in two equal
series-connected segments with the secondary positioned in
between will provide low leakage inductance. In this case,
56 turns per primary section are used.
The bias winding must provide sufficient power to
maintain operation when connected to a phase cut dimmer.
Empirical testing shows 17 to 20 volts minimum works well.
A bias winding of 16 turns ensures adequate voltage. The
transformer primary inductance is 1.9 mH.
Secondary bias can be simplified due to the lower LED
forward voltage. In this case, the regulator transistor can be
eliminated utilizing resistor R21 and zener D11 to establish
bias voltage. Further reduction in parts is possible in this
dimming application compared to a non-dimming
application. Since the load is well defined and the line
voltage is restricted, the maximum on-time capacitor limits
the peak power delivered such that the ’fast’ current control
loop utilized on the NCL30000LED evaluation board can be
eliminated.
The NCS1002 dual op-amp plus reference replaces the
dual op amp and separate reference. The op-amp connected
directly to the reference provides open load protection and
the second op-amp is the LED current regulator. The 0.2
ohm sense resistor keeps sensing losses to a minimum.
The schematic for the 115 V driver is shown in Figure 5
below. A complete bill of material is shown in Appendix A
at the end of this Application Note.
Complete design details for the NCL30000 are presented
in Application Notes AND8451 and AND8448. The 11 watt
power level is close to the 15 watt operation of the
demonstration board. As such, a similar EMI filter will be
used for this PAR30 design. The MOV surge limiter is
relocated across the input line for better circuit board
placement and to limit energy dissipated in the input
resistors R1 and R10. These input resistors are included for
TRIAC compatibility along with R4 and C3. The
component values depend on the input voltage range.
Designing for a narrow output voltage range allows some
simplifications to the original schematic, in particular, the
biasing networks. For dimming, the input waveform will be
chopped and the bias capacitor must store energy during the
active input periods and deliver bias power to the
NCL30000 during periods when the input is not present. The
narrow LED operating range allows elimination of
electrolytic capacitor C6. C8 is required for energy storage
and Q2 is needed to improve efficiency of regulator zener
diode D9.
Biasing for optocoupler U2 is provided by D8 and R14
without affecting the low current start up energy provided by
R7 and R13. Turn on time is controlled by R7 and R13.
Reducing the value of these resistors will speed turn on delay
but will adversely affect efficiency. Setting the resistance
too high will result in insufficient current for the base of Q2
and will limit bias power at low dimming settings. Selecting
R7 and R13 as 47K ohms provides turn on delay of 240 msec
for the 115 V lamp and 150K ohms provides 290 msec for
the 230 V lamp and performs well when dimming.
An EFD20 transformer core is used which fits the limited
volume inside the housing. The NCL30000 Design
Spreadsheet is used to establish transformer parameters. The
process begins with entering the input voltage range and
LED output parameters. A 500 V FET is sufficient for 115 V
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D9
MMBZ5245
15V
N
RV1
V275LA2
15 Ohm
C7
1nF
R14
4.7K
D8
MMBZ5239
9.1v
R13
47K
R7
47K
R1
R10 0 Ohm
R2
C1
470pF
5K6
R9
6.2K
R15
100K
C2
47nF
5K6
C9
470pF
4
3
2
1
U1
-
+
ZCD
GND
DRV
Vcc
NCL30000
CS
Ct
Comp
MFP
MMBTA06
Q2
L3 1.6mH
R3
4
D1
HD06
1
2
L2 800uH
5
6
7
8
C3
470nF
3
Ca
100pF
Rb
10K
Ra
2.2K
Da
MMBD7000
D6
BAS21
C4
100nF
C8
10uF
R4
240
10
R18
R20
0.5 OHM
100
Q3
NDD05N50Z
R19
Optional
Minimum
off-time
circuit
R16
47K
D5
MURA160
C5
4700 pF
8
FL2
T1D
FL1
C10 4.7 nF
U2
PS2561L_1
6
T1C
7
4
T1B
3
9
T1A
4
5
3
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Figure 5. 115V Lamp Schematic
2
L
+
3mA
C11
680uF
D10 MBRD5H100
R22
1.5K
D11
MMBZ5231
5.1V
C13
100nF
R21
3.3K
100pF
C14
R31
4.7K
R25 2.2K
R27
51K
1
2
3
4
R26
18K
U3
NCS1002
8
7
6
5
R28
680
D13
BAW56
0.2 ohm
R29
LED+
R30
24K
LED-
C15
220nF
R8
47K
24.4Volts
AND8463/D
AND8463/D
Performance Results
Data shown below in Table 1 was collected from each version of PAR30 lamp. The damper network comprised of R4 and
C3 improves performance when a TRIAC dimmer is used. This network dissipates energy and introduces some phase
displacement on input current. If dimming is not required, the damper network can be eliminated. Performance for each
configuration is shown below:
Table 1. Performance of PAR30 Lamps
Lamp
Version
RC
Damper
Present
Input
Power (W)
PF
%THD
Output
Current
(mA)
Output
Volts
(Vdc)
Output
Power (W)
Efficiency
(%)
115
Yes
12.91
0.98
10.2
452
23.61
10.67
82.7
No
12.72
0.99
6.5
452
23.60
10.67
83.9
Yes
13.00
0.87
23.4
453
23.60
10.69
82.2
No
12.59
0.97
11.2
453
23.44
10.62
84.4
230
As with any high power factor single stage converter
output ripple is filtered by the secondary side capacitor.
LEDs display a constant voltage characteristic and current
ripple is sensitive to the driver’s output ripple voltage where
higher capacitance minimizes ripple. Space is limited in this
application and a 680 mF capacitor was selected as the output
filter. Ripple current is shown in Figures 6 and 7 below.
Scale factor is 167 mA/division:
Figure 7. 393 mA pk-pk ripple current for 230V Lamp
The peak of the ripple current is maintained below the
maximum operating current of the LEDs selected.
Thermocouples were affixed to critical components and
the driver was enclosed in the lamp housing with the
heatsink attached in its expected configuration. LED
temperature was monitored on the aluminum base plate
adjacent to the LED module. The lamp was operated until
thermal equilibrium was achieved. Results are shown in
Table 2 below:
Figure 6. 320 mA pk-pk ripple current for 115V Lamp
Table 2. Thermal Test Results
Ambient
LEDs
Q3 FET
D10 Output Rectifier
Transformer
C11 output capacitor
17.8°C
56.9°C
75.2°C
82.0°C
72.4°C
57.8°C
Temp Rise
39.1°C
57.4°C
64.2°C
54.6°C
40.0°C
In a production integral LED lamp it is common to have
the power supply assembly encapsulated in a potting
compound. Potting will improve thermal transfer and
reduces hot spot temperatures.
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AND8463/D
IEC61000-3-2 Current Harmonics
Dimming Performance
The design passes Class C current harmonic requirements
for both 115 V and 230 V versions. Test results are shown
below in Table 3. Note these lamps also pass the more
stringent requirements for inputs equal to or greater than 25
watts.
The PAR30 LED lamp performs well with a variety of
commercially available TRIAC and electronic phase cut
dimmers. Dimming is continuous and predictable with
many dimmers providing control down to zero light output.
Table 4 below shows 115 V and Table 5 shows 230 V PAR30
lamp performance with various dimmers.
Table 3. Class C Current Harmonics
Lamp version
3rd Harmonic
(Limit 86%)
5th Harmonic
(Limit 61%)
115
5.94%
3.36%
230
16.6%
10.96%
Table 4. 115 V Version Lamp Dimmer Performance
Manufacturer
Dimmer Model
Min Conduction Angle
(degrees)
Current at Min Conduction Angle
(mA)
Cooper
Aspire 9530AA
9.9
1
Ding Chung
DC-310
9.1
5
GE
Rotary DI 61
<10.4
<1
Kuei Lin
AC 110V 500W
<9.1
<1
Leviton
CFL Slide 6673-P
33.9
57
Leviton
Electronic 6615-POW
56.6
116
Leviton
Illumatech IPI06
16
11
Leviton
Rotary OC58L1
<11
<2
Leviton
Sureslide 6633-PLW
<11
<1
Lutron
Digital Fade MAW-600H
13.6
17
Lutron
Skylark S-600
<9.9
<1
Lutron
Toggler TG-600PH
25.5
22
Pass & Seymour
D703PLAV
8.6
<1
Pass & Seymour
LS603PLAV
8.2
<1
Pass & Seymour
LSLV603PWV
<6.7
<1
SCT
YM-2508A
<8
<1
Table 5. 230 V Version Lamp Dimmer Performance
Manufacturer
Dimmer Model
Min Conduction Angle
(degrees)
Current at Min Conduction Angle
(mA)
Alombard
741021
10
<1
Clipsal
KB31RD400
12.6
<1
Clipsal
32V500
14
<1
Legrande
999.58
50
110
Lutron
LLSM-502
9
3
MK
SX8501
18.4
11
SCT
Y-25082A
15
6
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AND8463/D
Conducted EMI
Minimizing ’across the line’ or X-capacitance will reduce
current peaks when the TRIAC turns on. Oscillations in the
input filter will be reduced and TRIAC operation is more
predictable. Adding resistance in series with the input (R1
and R10) and an R-C damper (R4 and C3) reduce the
oscillations as well.
Figures 8 and 9 show the conducted EMI profiles for the
115 V and 230 V PAR30 lamps respectively.
An input filter is necessary to meet Class B conducted
EMI limits. The filter was carefully designed for
compatibility with TRIAC dimmers since excessive current
peaks when the TRIAC turns on will create oscillations in
the filter. If this occurs, the resultant damped sinusoid input
current can fall below the minimum TRIAC holding current
forcing the TRIAC off prematurely. Depending on the
TRIAC dimmer position and the line voltage the TRIAC
could re-fire resulting in visible flicker and added
component stress.
dBuV
80
70
60
EN 55022; Class B Conducted, Quasi−Peak
50
EN 55022; Class B Conducted, Average
40
30
20
10
Average
0
−10
−20
1
10
(Start = 0.15, Stop = 30.00) MHz
Figure 8. EMI Profile for 115 V Lamp
dBuV
80
70
60
EN 55022; Class B Conducted, Quasi-Peak
50
EN 55022; Class B Conducted, Average
40
30
20
10
Average
0
−10
−20
1
10
(Start = 0.15, Stop = 30.00) MHz
Figure 9. EMI Profile for 230 V Lamp
Conclusion
efficiency allows the thermally limited PAR30 envelope to
deliver more power to the LEDs and consume less power in
the driver. The basic design can be scaled up for higher
power to support PAR38 lamps.
A practical PAR30 LED lamp design based on the
NCL30000 LED controller is presented which meets the
design objectives. This circuit can be tailored to match drive
requirements for many different LED engines. The high
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AND8463/D
APPENDIX A: Bill Of Materials
Bill of Materials for the NCL300000 PAR30 Driver
Note: Parts specific to one version of Lamp are indicated as (115V) or (230V).
Designator
Value
Footprint
Manufacturer
C1
470pF
50V Ceramic COG, NPO
0603 SMD
Panasonic
ECJ-1VC1H471J
C2
47nF
300 VAC Film X1 (LS = 12.5 mm)
Box
Panasonic
ECQ-U3A473MG
C3 (115V)
470nF
450 V Metal Polyester Film (LS =
15mm)
Box
EPCOS
C3 (230V)
330nF
250 VAC Metallized Polyester Film
(LS=15 mm)
Box
Panasonic
ECQ-U2A334ML
C4
100nF
250 VAC X1 Metal Polyester Film
(LS = 15 mm)
Box
Panasonic
ECQ-U2A104ML
C5
4700 pF
500V Ceramic X7R
1206 SMD
Vishay
C7
1nF
50V Ceramic X7R
0603 SMD
Panasonic
ECJ-1VB1H102K
C8
10uF
50V Electrolytic, 5mm dia (LS =
2mm)
Radial
Panasonic
EEU-EB1H100S
C9 (115V)
470pF
50V Ceramic COG, NPO
0603 SMD
Panasonic
ECJ-1VC1H471J
C9 (230V)
180pF
50V Ceramic
0603 SMD
Panasonic
ECJ-1VC1H181J
C10
4.7 nF
250VAC Y5U X1Y1 (LS = 10mm)
Radial
Panasonic
CD16-E2GA472MYNS
C11
680uF
35V Aluminum Electrolytic
Radial
Panasonic
EEU-FM1V681
C13
100nF
25V Ceramic X7R
0603 SMD
Panasonic
ECJ-1VB1E104K
C14
100pF
50V Ceramic COG, NPO
0603 SMD
Panasonic
ECJ-1VC1H101J
C15
220nF
25V Ceramic X7R
0603 SMD
Panasonic
C1608XR1E224M
HD06-T
D1
HD06-T
D5
MURA160
D6
BAS21
D8
D9
Description
Manufacturer Part
Number
B32522N6474J
VJ1206Y472KXEAT5Z
Rectifier bridge, 600V, 0.8A
SMD
Diodes Inc.
600V, 1A
SMA
ON Semiconductor
MURA160T3
250V, 200mA
SOT23
ON Semiconductor
BAS21LT1G
MMBZ5239
9.1V ZENER
SOT23
ON Semiconductor
MMBZ5239BLT1
MMBZ5245
15V ZENER
SOT23
ON Semiconductor
MMBZ5245BLT1
MBRD5H100
Schottky, 100V, 5A
DPAK
ON Semiconductor
MBRD5H100T4G
D10 (230V)
MURD620
Rectifier, 200V, 6A
DPAK
ON Semiconductor
MURD620CT
D11
MMBZ5231
5.1V ZENER
SOT23
ON Semiconductor
MMBZ5231BLT1
D13
BAW56
70V, 200MA
SOT23
ON Semiconductor
BAW56LT1G
L2
800uH
Torroid
Through
Hole
Wurth Midcom
L3 (115V)
1.6mH
Torroid
Through
Hole
Wurth Midcom
L3 (230V)
800uH
Torroid
Through
Hole
Wurth Midcom
D10 (115V)
750311431 Rev 6A
750311431 Rev 6A
Q2
MMBTA06
NPN, 80V, 500mA
SOT23
ON Semiconductor
MMBTA06LT1G
Q3 (115V)
NDD05N50
N-Channel MOSFET 500V, 4.7A,
1.5R
DPAK
ON Semiconductor
NDD05N50ZT4G
Q3 (230V)
SPD02N80
N-Channel MOSFET 800V, 2A
DPAK
Infineon
SPD02N80C3
R1 (115V)
15
Fusible resistor, 1W
Axial
Vishay
NFR0100001509JR500
R1 (230V)
33R
Fusible resistor, 33R, 1W
NFR0100003309JR500
R2 R3
5K6
1/10W
R4 (115V)
240
Metal Film 1W
Axial
Vishay
0603 SMD
Panasonic
Axial
Vishay
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ERJ-3GEYJ562V
PR01000102400JR500
AND8463/D
Designator
Value
Description
Footprint
Manufacturer
Manufacturer Part
Number
R4 (230V)
510
Metal Film 1W
Axial
Vishay
PR01000105100JR500
R7 R13
(115V)
47K
1/4W
1206 SMD
Panasonic
ERJ-8ENF4702V
R7 R13
(230V)
150K
1/4W
1206 SMD
Vishay
ERJ-8ENF1503V
R8
47K
1/10W
0603 SMD
Panasonic
ERJ-3EKF4702V
R9
6K2
1/10W
0603 SMD
Panasonic
ERJ-3EKF6201V
R10 (115V)
Zero
Jumper
-
-
R10 (230V)
33R
Fusible resistor, 33R, 1W
Axial
Vishay
R14
4K7
1/10W
0603 SMD
Panasonic
ERJ-3EKF4701V
R15
100K
1/10W
0603 SMD
Panasonic
ERJ-3EKF1003V
R16
47K
1/10W
0603 SMD
Panasonic
ERJ-3EKF4702V
R18
100
1/10W
0603 SMD
Panasonic
ERJ-3EKF1000V
R19
10
1/10W
0603 SMD
Panasonic
ERJ-3EKF10R0V
R20
0.51
1/4W
1206 SMD
Rohm
R21
3.3K
1/4W
1206 SMD
Panasonic
ERJ-8ENF3301V
R22
1.5K
1/10W
0603 SMD
Panasonic
ERJ-3EKF1501V
R25
2.2K
1/10W
0603 SMD
Panasonic
ERJ-3EKF2201V
R26
18K
1/4W
1206 SMD
Panasonic
ERJ-8ENF1802V
R27
51K
1/4W
1206 SMD
Panasonic
ERJ-8ENF5102V
R28
680
1/10W
0603 SMD
Panasonic
ERJ-3GEYJ681V
R29
0.2
1/4W
1206 SMD
Rohm Semi
MCR18EZHFLR200
R30
24K
1/10W
0603 SMD
Panasonic
ERJ-3EKF2402V
R31
4K7
1/4W
1206 SMD
Panasonic
ERJ-8ENF4701V
RV1
V275LA2
275V 23 Joule (LS = 7mm)
Radial
Littelfuse
U1
NCL30000
Single Stage PFC LED Driver
SOIC8
ON Semiconductor
U2
PS2561L_1
80V, 50mA
SMT4
NEC Electronics
U3
NCS1002
CV/CC Secondary Controller
SOIC8
ON Semiconductor
SMD EFD20
Wurth Midcom
T1
EFD 20, 12 watt
NFR0100003309JR500
MCR18EZHFLR510
V275LA2P
NCL30000DR2G
PS2561L-1
NCS1002DR2G
750311620
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