ON Semiconductor NCL30073LED4GEVB User Manual
NCL30073LED4GEVB
15 W High Power Factor
LED Driver
Evaluation Board
User'sManual
Overview
This manual covers the specification, theory of operation,
testing and construction of the NCL30073LED4GEVB
evaluation board. The NCL30073 board demonstrates a
15 W high PF buck boost LED driver for a typical downlight
application.
Key Features
The key features of this evaluation board include:
• Low Parts Count
• TRIAC Dimmer Compatible
• High Power Factor
• Integrated Fault Protection
♦ Over Temperature on board (a PCB mounted PTC)
♦ Output Over Current
♦ Output Over Voltage
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EVAL BOARD USER’S MANUAL
Table 1. SPECIFICATIONS
Input voltage 207 − 253 V ac
Line Frequency 50 Hz
Power Factor (100% Load)
Output Voltage 72 V dc
Output Ripple 75% Pk − Pk
Output Current 200 mA dc ± 5%
Efficiency 88.5% Typ.
Start Up Time < 250 msec Typ.
0.9
Min
© Semiconductor Components Industries, LLC, 2017
July, 2017 − Rev. 0
Figure 1. Evaluation Board Photo
1 Publication Order Number:
EVBUM2505/D
NCL30073LED4GEVB
THEORY OF OPERATION
Power Stage
The power stage is a flying buck boost design. In this
configuration, drain of the switching FET is connected to the
rectified HVDC and the source is switching. This has many
benefits:
1. Direct output current sensing
2. Direct output voltage sensing
3. No Aux winding needed
The power stage operates as a fixed frequency DCM
power stage. The DCM allows for no forced commutation
of the output diode for good EMI performance. The fixed
current/fixed frequency provides for a constant power
control over a large portion of the input waveform. The
resistor divider of R27 and R29 provides some wave shaping
to improve the power factor. The input current waveform is
made to be square for maximum TRIAC dimmer
compatibility.
Figure 2.
Output Voltage Sense and Vcc generation
Dout1 is in parallel with the output during the off time of
the FET and stores energy in Cvcc. R36 and R37 divide the
output voltage and Q2 buffers it to provide Vcc power to the
controller. Since the divider is a fixed ratio, Vcc is a fixed
percentage of the output voltage. When Vcc rises above
25 V, the controller detects and OVP fault. The maximum
output voltage is set by adjusting the ratio of R36/R37.
In cases where the output has a lot of ripple current and the
LED has high dynamic resistance, the peak output voltage
can be much higher than the average output voltage. The
inductor winding will charge the Cvcc to the peak of the
output voltage which may trigger the OVP sooner than
expected so in this case the peak voltage of the LED string
is critical.
Protection
Thermal Protection
Rtco is a PTC connected between the CS pin and Rsens.
The controller creates and internal signal current from the
CS pin. As the resistance of Rtco becomes larger with
temperature, the signal level at the CS pin increases causing
the current to foldback with temperature.
Programmable OVP
R36 and R37 set Vcc as a fixed percentage of the output
voltage. The OVP threshold on the controller is 25 V. So the
ratio of R36/R37 is set to trip the Vcc OVP threshold at about
100 V output.
Overcurrent Protection
The controller has built in overcurrent limits.
Output Current
The output current is set by the value of Rsens. It’s
possible to adjust the output current by changing Rsens.
TRIAC Dimming Compatibility
The EMI filter components are selected to provide
optimum damping of the EMI filter to eliminate ringback of
the input current which will lead to loss of hold current in the
dimmer. The square nature of the input current makes the
best case for TRIAC holding current over the line cycle
while still maintaining power factor above 0.9.
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NCL30073LED4GEVB
SCHEMATIC
+HVDC_iso
AC_L
AC_N
+HVDC_iso
CVcc
10uF 100V
1
1
Dout1
MURA160T3G
R36
301k
F2
0A5
R37
100k
Q2
MMBT5551LT1G
RV1
MOV 250V
C8
10nF
412k
R29
L1
10mH
1
OPP
2
FB
3
CS
NCL30073
R27
10k
D4
+
AC1
−
AC2
MB6S
Figure 3. Input Circuit
R15
143k
R38
220k
U2
6
Vcc
5
Gdrv
4
Gnd
1uF 50V
C7
Rtco
680 PTC
C4
100nF 400V
Rdamp
680
C6
33nF 400V
Q1
NDD60N900U1T4G
t
Rsens
1.13
Dout
MURA160T3G
1
LED−
Cout
100uF100V
Figure 4. Main Circuit
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L5
1.2mH
1
LED+
NCL30073LED4GEVB
BILL OF MATERIAL
Table 2. BILL OF MATERIAL
Refer-
ence
CVcc 1
Cout 1
C4 1 100 nF 400 V Faratronic C212G104−4B****+++ Faratronic C212G104−4B****+++ Yes
C6 1 33 nF 400 V Faratronic C212G333−3A****+++ Faratronic C212G333−3A****+++ Yes
C7 1
C8 1 10 nF Yageo CC0603KRX7R9BB1
Dout1,
Dout
D4 1 MB6S MCC MB6S Digikey MB4S−TPMSCT−ND Yes
F2 1 0A5 Littelfuse 0263.500WRT1L Digikey F1999CT−ND Yes
L1 1 10 mH Wurth 744772103 Digikey 732−3791−ND Yes
L5 1 1.2 mH Wurth 750316243 Wurth 750316243 Yes
Q1 1 NDD60N900U1T4G ON
Q2 1 MMBT5551LT1G ON
RV1 1 MOV 250V Littelfuse V390ZA05P Digikey F3361−ND Ye s
Rdamp 1 680 Yageo RSF200JB−73−680R Digikey 680W−2−ND Yes
Rsens 1 1.13 Yageo RC1206FR−071R13L Digikey 311−1.13FRCT−ND Ye s
Rtco 1 680 PTC Epcos B59721A90A62 Digikey 495−4312−1−ND Ye s
R15 1 143k Yageo RC1206FR−07143KL Digikey 311−143KFRCT−ND Ye s
R27 1 10k Yageo RC0603FR−0710k0L Digikey 311−10.0KHRCT−ND Yes
R29 1 412k Yageo RC1206FR−07412KL Digikey 311−412KFRCT−ND Ye s
R36 1 301k Yageo RC0603FR−07301KL Digikey 311−301KHRCT−ND Yes
R37 1 100k Yageo RC0603FR−07100KL Digikey 311−100KHRCT−ND Yes
R38 1 220k Yageo RC1206FR−07220KL Digikey 311−220KFRCT−ND Ye s
U2 1 NCL30073 ON
Qty Part Distributor
10 mF 100 V
100 mF 100 V
1 mF 50 V
2 MURA160T3G ON
Rubycon 100YXJ10M5X11 Digikey
Nichicon UVK2A101MPD Digikey
Yageo CC0805KKX7R9BB1
Semiconductor
Semiconductor
Semiconductor
Semiconductor
Distributor
Part Number
05
03
MURA160T3G ON
NDD60N900U1T4G ON
MMBT5551LT1G ON
NCL30073 ON
Manufacturer
Digikey 311−1886−1−ND Yes
Digikey 311−1085−1−ND Yes
Semiconductor
Semiconductor
Semiconductor
Semiconductor
Manufacturer
Part Number
1189−2150−ND
UVK2A101MPD−ND
MURA160T3G No
NDD60N900U1T4G No
MMBT5551LT1G No
NCL30073 No
Substitution
Allowed
Yes
Yes
NOTE: All components to comply with RoHS 2002/95/EC
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