NSIC20x0JB: Direct-AC, Linear LED Driver Topology: CCR Straight Circuit (120 VAC & 230 VAC)

DN05079/D
Design Note – DN05079/D
Direct-AC, Linear LED Driver Topology:
CCR Straight Circuit (120 VAC & 230 VAC)
Device
Application
Topology
Efficiency
Input Power
Power
Factor
NSIC20x0JB
AC LED Lighting
Direct AC,
Linear
68 – 84 %
Variable
6 – 14 W
0.92 – 0.97
THD
20 – 39%,
Variable
Figure 1 – General “Straight Circuit” CCR-based LED Driver Schematic
performance, which will be referred to and
supported by this note.
Overview
This document presents a simple, low-cost LED
driver topology useful for AC LED lighting solutions
at any mains voltage or frequency. This costeffective driver design combines good power factor,
simplicity, high efficiency, and impressive driver
scalability in a very adaptive and versatile platform
solution.
The circuit is designed for use within a wide input
voltage range, and can be made to operate
anywhere between 90 VAC and 300 VAC. The driver
works best when optimized for a specific supply
voltage range (such as 100 – 130 VAC or 190 – 250
VAC), which may influence LED load design.
The circuit employs ON Semiconductor Constant
Current Regulators (CCRs) to regulate LED current
and protect LEDs from over-voltage conditions. This
driver is extremely scalable, and can support many
modular extensions for circuit tuning and
August 2015, Rev. 0
The driver traditionally drives a single LED load,
which may be composed of multi-junction highvoltage (HV) LEDs or multiple standard low-voltage
LEDs. The “LED String” may flexibly represent a
high-voltage string of multiple LEDs, or a single
COB LED. The LED load will need to be
appropriately designed for CCR over-voltage
considerations, and this note will discuss conditions
and refer to protection techniques.
The circuit is protected from mains transients by a
fuse and metal-oxide varistor. The driver can also
accommodate EMI filtering techniques.
This technical note will first overview general
behaviors of the circuit, identify design-dependent
performance parameters, and then finish off with a
closer examination of six specific designs.
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Key Features
•
•
•
•
•
•
•
•
•
•
Wide input voltage range.
High-voltage transient and tolerance
protection.
Simple, low-cost implementation.
Simple and flexible load design, highly
compatible with COB implementations.
High power factor across voltage range.
Modular design flexibility, can accommodate
many functions (EMI filter, OVP, etc.)
Compatible with most phase-cut dimmers.
Adjustable for different LED voltages.
Scalable for different currents/power levels.
Predictable electrical performance
Circuit Description
The circuit consists of, at a minimum, a full-wave
bridge rectifier (D1 – D4), a current regulator (“CCR”),
and an LED load (represented by “LED String”)
connected in series, as shown in Figure 1. Other
more specific schematics are shown later on in
Figures 3, 11-16.
For high-voltage (220 VAC and above) or low load
voltage (see Fig. 10) an OVP block is recommended,
which as described by Figure 2 and shown in Figure
3b, consists of a threshold detector (R1 – R2, Q1),
pass transistor network (Q2, R3), and power resistor
(R4).
Circuit Operation and Design
The bridge rectifier outputs a half-wave sine peaking
at about 170 V for 120 VAC, and about 320 V for 230
VAC. This bridge output is referenced between the
cathodes of D2 and D4 to the anodes of D1 and D3.
The circuit drives the LED load directly off of the
output of the bridge voltage, hence the name “directAC.” The driver’s design philosophy is to achieve
maximum simplicity with minimum component count.
For a more streamlined approach, this note will only
overview OVP schemes in particular cases.
August 2015, Rev. 0
The driver’s operation is very simple to understand.
As a linear driver, the CCR requires a voltage drop to
perform regulation (typ. 1.8 V minimum), and for the
LEDs to turn on, there must be sufficient voltage
provided by the bridge. Therefore, the combination of
these two conditions means that light will only be
produced when the bridge voltage is above the LEDs
and minimum CCR voltage combined.
𝐸𝐸. 1)
𝐵𝐵𝐵𝐵𝐵𝐵 ≥ 1.8 𝑉𝐴𝐴 + 𝐿𝐿𝐿 𝑉𝑓
As the LEDs will turn on with high voltage, they must
turn off with low voltage. This lends the driver a “duty
cycle”-like effect, determined by the magnitude of the
LED load voltage. Furthermore, standard phase-cut
dimming modifies the phase length of this duty cycle,
emulating PWM-like behavior and avoiding the nonlinear light creation of current modulation. Whether
dimming or not, this duty-cycle behavior inherently
increases LED lifetime and reliability.
When the LEDs are on, the remaining voltage is
dropped on the CCR or current regulator, which in
most cases, directly connects the bridge and LEDs,
as implied in Eq. 2 below.
𝐸𝐸. 2)
𝑉𝑏𝑏𝑏𝑏𝑏𝑏 (𝑡) = 𝑉𝐶𝐶𝐶 (𝑡) + 𝑉𝑓
This is the source of most of the power lost in a
straight circuit driver topology, as there will inherently
be a mismatch between the varying sine-wave bridge
voltage waveform and the DC-like LED load, the
difference yielding power dissipation on the CCR.
This effect becomes more exaggerated as the LED
load voltage decreases, or the supply voltage
increases. Figures 8 and 9 and Table 9 together
illustrate this characteristic.
If at any time the CCR is at risk of over-voltage
conditions (the maximum possible VCCR,PK is above
the maximum voltage rating), then special OVP
protection circuitry will need to be deployed to ensure
reliable operation, which will be discussed in the next
section.
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DN05079/D
Figure 2 – General “Straight Circuit” CCR-based LED driver block diagram with OVP functionality.
With High-Voltage Protection Circuitry
VOVP(Q1) = 101 V. This would be an appropriate
protection level for a 120 V CCR.
If the driver is at risk of an over-voltage scenario,
then additional circuitry will be necessary to monitor
the CCR VAK and take protective measures when
necessary. The general condition for over-voltage
protection necessity is given by Eq. 3.
𝐸𝐸. 3)
𝑉𝐴𝐴,𝑚𝑚𝑚 > 𝑉𝐼𝐼,𝑚𝑚𝑚,𝑅𝑅𝑅 ⋅ √2 − 𝑉𝐹,𝑙𝑙𝑙𝑙
An adequately protected circuit is shown in Figure 3b,
taken from the AND9179/D application note, which
overviews many other different types of over-voltage
protection not covered in this technical note.
The protection circuit used in these 230 VAC designs
roughly measures the VAK across CCR1. As a highvoltage threshold detector, Q1 controls whether
current passes through a transistor (Q2), or a highvoltage power resistor (R4). When the VAK threshold
set by the designer is surpassed (according to Eq. 4
below), Q2 turns off, and the power resistor R4 takes
on some of the voltage drop from the CCR, according
to Ohm’s Law. If properly designed, the R4 resistor
momentarily reduces the VAK on the CCR, allowing
higher input voltages to be tolerated without
exceeding device voltage ratings.
𝐸𝐸. 4)
𝑉𝑂𝑂𝑂(𝑄1) = 𝑉𝐵𝐵(𝑠𝑠𝑠) ⋅
𝑅1 + 𝑅2
𝑅2
Let’s consider a design example protecting a 120 V,
30 mA CCR, such as the NSIC2030JBT3G. To
provide sufficient margin below the device rating, let’s
design the OVP to activate around 100 V. When
using an MMBT3904L (expected VBE(sat) of 0.68 V at
25 °C) as Q1 to trigger the OVP, Eq. 4 yields resistor
values R1 = 1 MΩ and R2 = 6.8 kΩ to produce
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As mentioned earlier, the power resistor R4 (as
shown in Figure 3b), needs to be carefully considered
so as to best protect its companion CCR network.
Thankfully, only Ohm’s Law must be considered: the
desired voltage drop on the resistor divided by total
instantaneous CCR current yields the proper resistor
value, as shown in Eq. 5. Bear in mind that the
desired resistor voltage drop must be less than the
voltage that the OVP triggers at, so that the CCR
remains in full regulation during the transition. For
additional support, see Eq. 6 of application note
AND9179/D.
𝐸𝐸. 5)
𝑉𝐷𝐷𝐷𝐷,𝑅4 = 𝐼𝐶𝐶𝐶,𝑚𝑚𝑚 ⋅ 𝑅4
It follows that the Q2 device ratings are determined
by the maximum instantaneous CCR current
(ICCR,max), as well as the expected voltage drop on the
R4 resistor (VDROP,R4). R3 should be selected as to
provide sufficient base current for the Q2 transistor.
It should be noted that this over-voltage protection
scheme does not degrade the quality or amount of
light produced—it only saves the LED driver when
the VAK approaches unsafe levels, as determined by
the designer. The output power over the LEDs is
maintained when using a VAK-sensitive scheme like
this, although the driver’s increased voltage drop
means that circuit efficiency is reduced at high
voltages.
Although only one design is featured in this note,
many different OVP techniques and circuit
schematics are reviewed further in the application
notes AND9179/D and AND9203/D.
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DN05079/D
Practical implementations of the circuits represented
by Figures 1 and 2 (with and without OVP) are
shown here with waveforms for quick, conceptual
reference, in accordance with the designators used
above. All the specific designs reviewed in this
design note will be one of these two templates below.
Figure 3: General straight circuit implementations for any mains voltage, shown a) without OVP, and b) with OVP.
General Waveforms
Below are screenshots demonstrating waveforms of
generic straight circuit performance, with and without
OVP. The first three screenshots (Fig. 4 – 6) are from
a 120 VAC driver utilizing a 120 VF LED load and
50mA CCR. The fourth screenshot (Fig. 7) is a 230
VAC driver utilizing a 180 VF LED load and 20 mA
CCR.
The OVP is implemented on only 230 VAC designs,
and not on 120 VAC designs in this note, though OVP
is not necessarily exclusive to high line voltages. This
necessity is conditional on the relationship between
the supply and load voltage levels (see Eq. 2, Fig.
10).
Figure 4 – The total input current follows the voltage waveform very closely, yielding high power factor
and good THD performance. LED current is the supply current after rectification.
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DN05079/D
Figure 5 – A simple photodetector circuit using a NOA1212 was used to generate a waveform of the LED
light output for flicker index measurements in this design note. Efficacy and light intensity vary by LED,
but the general waveform shape and linear current-light relationship are maintained.
Figure 6 – Output voltage and LED current waveforms indicate no flicker when used with TRIAC dimming
shown in the maximum position. This particular dimmer sports a non-zero output filter voltage during the
“off” state, but the circuit receives little-to-no input current when the TRIAC is off, and the current is
normal when the TRIAC is on.
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DN05079/D
Figure 7 – With the over-voltage protection circuitry, the circuit monitors and throttles the peak voltages
exercised on the CCR. In this case, we use a resistor to drop excess voltage to prevent damaging the
CCR. Output current remains roughly constant while LEDs are on.
Design Dependencies and Tradeoffs
Many of the electrical and optical performance
characteristics of this driver are dependent on the
relationship of the LED load voltage and application
voltage range. The simplicity of the straight circuit
makes many factors mathematically predictable,
lending incredible insight into the design process. For
the figures below, LED load voltage has been
normalized to the peak line voltage, so as to provide
the most generalized analysis.
As seen in Figures 8 and 9 below, input power,
efficiency, and thermals improve with high load
voltages, whereas many other characteristics,
including power factor, THD, and dimming
performance improve with lower load voltages. It is
the careful balancing of these trends that yields a
successful design.
Figure 8 below illustrates a few trends that are
mathematically predictable, and are determined
based upon the behavior of a sine wave compared to
a DC level. Figure 8 may be loosely referenced
during the design phase when considering very
critical parameters, such as efficiency, total current,
and power estimation. Figure 9 displays empirically
validated trends on a graph as a function of LED
voltage, normalized to the bridge voltage peak.
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The “Decreasing VF” and Increasing VAC” scenarios
described in Table 1 generally correspond to a shift
to the left-ward shift on the Fig. 8 and 9 plots,
whereas the “Increasing VF” and “Decreasing VAC”
trends correspond to an increase in normalized
forward voltage, and shift the plot point to the right.
These mathematical models neglect circuit and
environmental effects on LED forward voltage, such
as VF decrease due to self-heating and rising
ambient temperature range, or VF increase due to
ohmic behavior in the LEDs while increasing current.
Generally, these parameters change, driver
performance can be expected to move up and down
these curves.
Figure 10 provides a rough graphical characteristic
displaying “critical LED load voltage” as a function of
input RMS voltage. The critical LED load voltage, in
this case, is a condition for the load voltage below
which some protective circuitry will be required for
CCR reliability. When LED voltages are low, CCRs
experience high peak voltages, and care must be
taken so as not to surpass voltage breakdown levels.
The plot given in Figure 10 incorporates a 10 V
margin on the CCR’s maximum voltage. The
equation determining the boundary condition for
critical LED load voltage is given in Eq. 3.
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DN05079/D
Predictive Performance vs. LED Load Voltage
Normalized to Peak Bridge Voltage
Conduction Time, Efficiency, % of Pmax/Ireg
(Percent, %)
Conduction Time (%)
Efficiency (%)
% of Pmax
0.2
0.4
Irms (% of Ireg)
Pout ( % of Pdc = Vf*Ireg)
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
0.0
0.1
0.3
0.5
0.6
0.7
0.8
Normalized Forward Voltage (Vf/Vbridge,max)
0.9
1.0
Figure 8: Certain parameters useful in predicting driver performance are mathematically dependent on VF.
Measured Performance v. LED Load Voltage
Normalized to Peak Bridge Voltage
Meas. Efficiency (%)
THD (%)
PF
Min Dimming Level
1
90%
0.9
80%
0.8
70%
0.7
60%
0.6
50%
0.5
40%
0.4
30%
0.3
20%
0.2
10%
0.1
Power Factor
Efficiency, THD, Minimum Dimming Level, % DC
Efficacy
(Percent, %)
% of DC Efficacy
100%
0
0%
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Normalized Forward Voltage (VF/VPk)
Figure 9: While not necessarily formulaic, real trends of critical performance parameters exist across VF.
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DN05079/D
Performance
Decreasing VF
Increasing VF
Decreasing VAC
Increasing VAC
IRMS(IN) (mA)
Small Increase
Small Decrease
Decrease
Increase
PF
Small Increase
Small Decrease
Small Decrease
Small Increase
THD (IRMS, %)
Decrease
Increase
Increase
Decrease
PIN (W)
Increase
Decrease
Decrease
Increase
POUT (W)
Non-linear
Non-linear
Non-linear
Non-linear
Efficiency (%)
Decrease
Increase
Increase
Decrease
Min. Dimming Level (%)
Decrease
Increase
No effect
No effect
Effective Duty Cycle (%)
Increase
Decrease
Decrease
Increase
Flicker Index
Decrease
Increase
Increase
Decrease
CCR Temperature (°C)
Increase
Decrease
Decrease
Increase
Table 1 – General trends for the circuit shown in Figure 1. Preferred/improved results indicated in shaded boxes.
Critical Load Voltage v. AC Mains Voltage
Straight Circuit Topologies, 10 V Margin
Using 120 V CCR
450
Using 45/50 V CCR
Critical LED Load Voltage (V)
400
VIN = 305, VLED = 396
VIN = 277, VLED = 357
350
VIN = 305, VLED = 321
VIN = 240, VLED = 304
300
VIN = 277, VLED = 282
VIN = 220, VLED = 276
250
VIN = 240, VLED = 229
VIN = 220, VLED = 201
200
VIN = 132, VLED = 152
VIN = 120, VLED = 135
VIN = 108, VLED = 118
150
100
VIN = 90, VLED = 92
VIN = 132, VLED = 77
VIN = 120, VLED = 60
VIN = 108, VLED = 43
50
VIN = 90, VLED = 17
0
0
50
100
150
200
AC Line Voltage (RMS)
250
300
350
Figure 10: Below the critical LED load voltage, protective circuitry will be needed to keep CCRs within their safe
operating regions. The figure above incorporates a 10 V margin from the maximum CCR voltage rating. Source
equation is given by Eq. 3 in this technical note.
August 2015, Rev. 0
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DN05079/D
Case 1: 6 W, 120 VAC Driver Design
Case 1 is a driver design of about 6 W input power, intended for 120 VAC mains. This design does not employ any
OVP on the CCR. Depending on the load design, this may be acceptable—use Eq. 3 to determine if OVP is
necessary on this circuit. If so, refer to the design in “Case 4” for further guidance.
Figure 11 – Schematic of straight circuit without over-voltage protection (OVP).
Bill of Materials
Designator
Manufacturer
Part No.
Qty
Description
Value
Tolerance
CCR1
ON Semi
NSIC2050JB
1
Constant Current Regulator
120 V, 50 mA
±15%
CCR2
F1
MOV1
D1 – D4
LED
ON Semi
Any
Any
ON Semi
Any
NSIC2030JB
MRA4004
-
1
1
1
4
*
Constant Current Regulator
Fuse
Varistor
Diode
Light-Emitting Diode
120 V, 30 mA
200 V, 1 A
150 VAC
400 V, 1 A
120 V, 90 mA
±15%
-
* The LED bank design may be composed of a few COB implementations or many single-junction 3V LEDs.
Table 2 – Bill of materials for the circuit shown in Figure 11.
Circuit Data
108 VAC
114 VAC
120 VAC
126 VAC
132 VAC
IRMS(IN) (mARMS)
PF
THD (IRMS, %)
PIN (W)
POUT (W)
Efficiency (%)
58.33
0.9296
39.5 %
5.88 W
4.74 W
80.6 %
58.67
0.9421
35.5 %
6.33 W
4.89 W
77.2 %
57.99
0.9521
32.0 %
6.65 W
4.91 W
73.7 %
57.67
0.9589
29.6 %
6.99 W
4.98 W
71.2 %
57.09
0.9649
27.3 %
7.28 W
4.990 W
68.5 %
Min. Dimming Level (%)
Effective Duty Cycle (%)
Flicker Index
3.9 %
50.8 %
0.464
3.7 %
54.1 %
0.434
3.8 %
57.0 %
0.411
3.8 %
59.5 %
0.388
3.8 %
61.6 %
0.373
Table 3 – Electrical characteristics for the circuit shown in Figure 11.
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DN05079/D
Case 2: 10 W, 120 VAC Driver Design
Case 2 is a driver design of about 10 W input power, intended for 120 VAC mains. This design does not employ
any OVP for the CCR. Depending on the load design, this may be acceptable—use Eq. 3 to determine if OVP is
necessary on this circuit. If so, refer to Case 4 for further guidance.
Figure 12 – Schematic of straight circuit without over-voltage protection (OVP).
Bill of Materials
Designator
Manufacturer
Part No.
Qty
Description
Value
Tolerance
CCR1 – 2
CCR3
F1
MOV1
D1 – D4
LED
ON Semi
ON Semi
Any
Any
ON Semi
Any
NSIC2050JB
NSIC2030JB
MRA4004
-
2
1
1
1
4
*
Constant Current Regulator
Constant Current Regulator
Fuse
Varistor
Diode
Light-Emitting Diode
120 V, 50 mA
120 V, 30 mA
200 V, 1 A
150 VAC
400 V, 1 A
120 V, 130 mA
±15%
±15%
-
* The LED bank design may be composed of a few COB implementations or many single-junction 3V LEDs.
Table 4 – Bill of materials for the circuit shown in Figure 12.
Circuit Data
108 VAC
114 VAC
120 VAC
126 VAC
132 VAC
IRMS(IN) (mA)
93.37
94.16
93.13
92.65
91.81
PF
THD (IRMS, %)
PIN (W)
POUT (W)
Efficiency (%)
Min. Dimming Level (%)
0.9298
39.40
9.391
7.887
84.0
2.8 %
0.9424
35.33
10.122
8.156
80.6
2.8%
0.9533
31.57
10.704
8.107
75.7
2.4 %
0.9603
28.96
11.220
8.239
73.4
2.8%
0.9657
26.80
11.716
8.293
70.8
2.9 %
Effective Duty Cycle (%)
Flicker Index
51.23
0.46
53.36
0.43
56.69
0.41
59.90
0.38
62.15
0.37
Table 5 – Electrical characteristics for the circuit shown in Figure 12.
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DN05079/D
Case 3: 14 W, 120 VAC Driver Design
Case 3 is a driver design with roughly 14 W nominal input power, intended for 120 VAC mains. This design does
not employ any OVP on the CCR. Depending on the load design, this may be acceptable—use Eq. 3 to determine
if OVP is necessary on this circuit. If so, refer to Case 4 for further guidance.
Figure 13 – Schematic of straight circuit without over-voltage protection (OVP).
Bill of Materials
Designator
Manufacturer
Part No.
Qty
Description
Value
Tolerance
CCR1 – 3
CCR4
F1
MOV1
D1 – D4
LED
ON Semi
ON Semi
Any
Any
ON Semi
Any
NSIC2050JB
NSIC2030JB
MRA4004
-
3
1
1
1
4
*
Constant Current Regulator
Constant Current Regulator
Fuse
Varistor
Diode
Light-Emitting Diode
120 V, 50 mA
120 V, 30 mA
200 V, 1 A
150 VAC
400 V, 1 A
120 V, 180 mA
±15%
±15%
-
* The LED bank design may be composed of a few COB implementations or many single-junction 3V LEDs.
Table 6 – Bill of materials for the circuit shown in Figure 13.
Circuit Data
108 VAC
114 VAC
120 VAC
126 VAC
132 VAC
IRMS(IN) (mA)
124.20
124.95
124.30
122.72
120.77
PF
THD (IRMS, %)
PIN (W)
POUT (W)
Efficiency (%)
Min. Dimming Level (%)
0.924
41.3 %
12.49 W
10.33 W
82.7 %
2.6 %
0.9381
36.8 %
13.36 W
10.62 W
79.4 %
2.5 %
0.949
33.2 %
14.13 W
10.76 W
76.2 %
2.4 %
0.9567
30.32 %
14.787 W
10.768 W
72.8 %
2.4 %
0.9628
27.95
15.324
10.734
70.0 %
2.4 %
Effective Duty Cycle (%)
Flicker Index
49.97 %
0.47
53.53 %
0.44
55.18 %
0.42
58.10 %
0.39
61.10 %
0.38
Table 7 – Electrical characteristics for the circuit shown in Figure 13.
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Case 4: 6 W, 230 VAC Driver Design
Case 4 is a driver design of about 6 W input power, intended for 220 – 240 VAC mains. This driver design employs
OVP to safely interface the LEDs and CCRs with high line voltages. Depending on the load design, this may or
may not be needed—use Eq. 3 to determine if OVP is necessary when driving any LED load.
Figure 14 – Schematic of straight circuit LED driver with over-voltage protection (OVP).
Bill of Materials
Designator
Manufacturer
Part No.
Qty
Description
Value
Tolerance
CCR1
R1
R2
R3
R4
Q1
Q2
F1
MOV1
D1 – D4
LED
ON Semi
Any
Any
Any
Any
ON Semi
ON Semi
Any
Any
ON Semi
Any
NSIC2030JB
MMBT3904L
NSS1C201L
MRA4007
-
1
1
1
1
1*
1
1
1
1
4
**
Constant Current Regulator
Resistor
Resistor
Resistor
Resistor
NPN Transistor
Low VCE,Sat NPN Transistor
Fuse
Varistor
Diode
Light-Emitting Diode
120 V, 20 mA
1 MΩ, 1/8 W
6.8 kΩ, 1/8 W
100 kΩ, 1/8 W
3.0 kΩ, ½ W
40 V, 100 mA
100 V, 2.0 A
200 V, 1 A
300 VAC
1000 V, 1 A
120 V, 20 mA
± 15%
± 1%
± 1%
± 10%
± 5%
-
* The power resistor may be a single resistor or multiple series/parallel components to optimize cost, space, etc.
** The LED bank design may be composed of a few COBs or many single-junction 3V LEDs.
Table 8 – Bill of materials for the circuit shown in Figure 14.
Circuit Data
IRMS(IN) (mA)
PF
THD (IRMS, %)
PIN (W)
POUT (W)
Efficiency (%)
Effective Duty Cycle (%)
Flicker Index
190 VAC
220 VAC
240 VAC
264 VAC
277 VAC
25.61
0.946
34.4 %
4.616 W
3.366 W
72.9 %
54.7 %
0.42
27.42
0.961
28.4 %
5.82 W
4.569 W
78.6 %
62.7 %
0.36
28.25
0.967
26.1 %
6.57 W
5.32 W
80.9 %
66.1 %
0.33
28.56
0.975
22.6 %
7.36 W
5.68 W
77.2 %
69.4 %
0.29
28.43
0.978
20.9
7.71 W
5.75 W
74.6
71.0 %
0.28
Table 9 – Electrical characteristics for the circuit shown in Figure 14.
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DN05079/D
Case 5: 10 W, 230 VAC Driver Design
Case 1 is a driver design of about 10 W input power, intended for 220 – 240 VAC mains. This design employs a
simple OVP scheme to protect the CCR. Depending on the load design, this may not be needed—use Eq. 3 to
determine if OVP is necessary on this circuit.
Figure 15 – Schematic of straight circuit with over-voltage protection (OVP).
Bill of Materials
Designator
Manufacturer
Part No.
Qty
Description
Value
Tolerance
CCR1 – 2
R1
R2
R3
R4
Q1
Q2
F1
MOV1
D1 – D4
LED
ON Semi
Any
Any
Any
Any
ON Semi
ON Semi
Any
Any
ON Semi
Any
NSIC2030JB
MMBT3904L
NSS1C201L
MRA4007
-
2
1
1
1
1*
1
1
1
1
4
**
Constant Current Regulator
Resistor
Resistor
Resistor
Resistor
NPN Transistor
Low VCE,Sat NPN Transistor
Fuse
Varistor
Diode
Light-Emitting Diode
120 V, 30 mA
1 MΩ, 1/8 W
6.8 kΩ, 1/8 W
100 kΩ, 1/8 W
1.5 kΩ, 1 W
40 V, 100 mA
100 V, 2.0 A
200 V, 1 A
300 VAC
1000 V, 1 A
120 V, 60 mA
± 15%
± 1%
± 1%
± 10%
± 5%
-
* The power resistor may be a single resistor or multiple series/parallel components to optimize cost, space, etc.
** The LED bank design may be composed of a few COBs or many single-junction 3V LEDs.
Table 10 – Bill of materials for the circuit shown in Figure 14.
Circuit Data
IRMS(IN) (mA)
PF
THD (IRMS, %)
PIN (W)
POUT (W)
Efficiency (%)
Effective Duty Cycle (%)
Flicker Index
190 VAC
220 VAC
240 VAC
264 VAC
277 VAC
49.57
0.941
35.8 %
8.88 W
6.73
75.8 %
53.8 %
0.4104
52.78
0.959
29.5 %
11.1 W
9.10 W
82.0 %
61.9 %
0.3480
53.79
0.968
25.9 %
12.53 W
9.96 W
79.5 %
65.9 %
0.3190
53.90
0.976
22.4 %
13.89 W
10.46 W
75.3 %
69.0 %
0.2889
53.26
0.979
20.9 %
14.44 W
10.48 W
72.6 %
70.8 %
0.2763
Table 11 – Electrical characteristics for the circuit shown in Figure 15.
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DN05079/D
Case 6: 14 W, 230 VAC Driver Design
Case 6 is a driver design of about 14 W input power, intended for 220 – 240 VAC mains. This design employs a
simple OVP scheme to protect the CCR. Depending on the load design, this may not be needed—use Eq. 3 to
determine if OVP is needed on this circuit.
Figure 16 – Schematic of straight circuit with over-voltage protection (OVP).
Bill of Materials
Designator
Manufacturer
Part No.
Qty
Description
Value
Tolerance
CCR1 – 2
R1
R2
R3
R4
Q1
Q2
F1
MOV1
D1 – D4
LED
ON Semi
Any
Any
Any
Any
ON Semi
ON Semi
Any
Any
ON Semi
Any
NSIC2050JB
MMBT3904L
NSS1C201L
MRA4007
-
2
1
1
1
1*
1
1
1
1
4
**
Constant Current Regulator
Resistor
Resistor
Resistor
Resistor
NPN Transistor
Low VCE,Sat NPN Transistor
Fuse
Varistor
Diode
Light-Emitting Diode
120 V, 50 mA
1 MΩ, 1/8 W
6.8 kΩ, 1/8 W
100 kΩ, 1/8 W
910 Ω, ½ W
40 V, 100 mA
100 V, 2.0 A
200 V, 1 A
300 VAC
1000 V, 1 A
120 V, 100 mA
± 15%
± 1%
± 1%
± 10%
± 5%
-
* The power resistor may be a single resistor or multiple series/parallel components to optimize cost, space, etc.
** The LED bank design may be composed of a few COBs or many single-junction 3V LEDs.
Table 12 – Bill of materials for the circuit shown in Figure 14.
Circuit Data
IRMS(IN) (mA)
PF
THD (IRMS, %)
PIN (W)
POUT (W)
Efficiency (%)
Effective Duty Cycle (%)
Flicker Index
190 VAC
220 VAC
240 VAC
264 VAC
277 VAC
59.01
0.942
35.7 %
10.59 W
8.06 W
76.2 %
54.4 %
0.4276
62.73
0.960
29.0 %
13.29 W
10.68 W
80.4 %
61.7 %
0.3445
62.67
0.969
25.4 %
14.60 W
11.40 W
78.1 %
65.6 %
0.3107
61.06
0.976
22.2 %
15.74 W
11.53 W
73.3 %
68.8 %
0.2831
59.33
0.979
20.6 %
16.07 W
11.32 W
70.4 %
70.4 %
0.2712
Table 13 – Electrical characteristics for the circuit shown in Figure 16.
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DN05079/D
Further Reference
For similar designs and related material, see the following ON Semiconductor technical publications.
•
Design Note – DN05013/D: Simple ENERGY STAR ® Compliant LED Driver Retrofit in a T5 Tube
using 160mA CCR
http://www.onsemi.com/pub_link/Collateral/DN05013-D.PDF
•
Application Note – AND9179/D: In-Driver High Voltage Protection Techniques for Constant Current
Regulators
http://www.onsemi.com/pub_link/Collateral/AND9179-D.PDF
•
Application Note – AND9203/D: Optimizing CCR Protection for Minimal Part Count
http://www.onsemi.com/pub_link/Collateral/AND9203-D.PDF
© 2015 ON Semiconductor.
Disclaimer: ON Semiconductor is providing this design note “AS IS” and does not assume any liability arising from its use; nor does ON
Semiconductor convey any license to its or any third party’s intellectual property rights. This document is provided only to assist
customers in evaluation of the referenced circuit implementation and the recipient assumes all liability and risk associated with its use,
including, but not limited to, compliance with all regulatory standards. ON Semiconductor may change any of its products at any time,
without notice.
Design note created by Travis Alexander, e-mail: [email protected]
August 2015, Rev. 0
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