UM0670
User manual
80 W offline LED driver with PFC
1
Introduction
The use of high power LEDs in lighting applications is becoming increasingly popular due to
rapid improvements in lighting efficiency, longer life, higher reliability and overall cost
effectiveness. Dimming functions are more easily implemented in LEDs, and they are more
robust and offer wider design flexibility compared to other light sources.
For this reason a demonstration board for driving high brightness and power LEDs has been
developed. The STEVAL-ILL013V1 demonstration board is an 80 W offline dimmable LED
driver with high power factor (PF) intended for fixed number of LEDs, the overall design of
which is described in detail in this user manual.
The LED current can be set to 350 mA, 700 mA and 1000 mA, using jumpers. Additionally,
a dimming function using a PWM (pulse width modulation) signal is implemented as well,
allowing the user to set the LED brightness from 0% up to 100%. The demonstration board
can be ordered using order code STEVAL-ILL013V1, and is shown in
Figure 1.
STEVAL-ILL013V1 main features
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80 W LED driver
350 mA, 700 mA and 1 A LED current settings
High efficiency (~90%)
Wide input voltage range: 88 to 265 VAC
High power factor: 0.99 for 110 VAC and 0.98 for 230 VAC
Universal PWM input for dimming (external board required)
Non-isolated SMPS
Brightness regulation between 0% and 100%
EMI filter implemented
EN55015 and EN61000-3-2 compliant
STEVAL-ILL013V1 demonstration board
Figure 1.
August 2009
Doc ID 15327 Rev 2
1/43
www.st.com
Contents
UM0670
Contents
1
2
3
4
5
6
7
8
9
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Design concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
STEVAL-ILL013V1 technical details . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
STEVAL-ILL013V1 performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Dimming function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
9.1
9.2
9.3
9.4
9.5
Output waveform measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Power MOSFET turn ON and OFF time . . . . . . . . . . . . . . . . . . . . . . . . . . 22
LED current ripple reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Standard EN61000-3-2 measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
EMI measurement (EN55015) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
10
Design features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
10.1
10.2
Proper startup circuit design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Zero dimming design implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
11
References and related materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Appendix A Design calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
A.1
Design specifications for a modified buck convertor . . . . . . . . . . . . . . . . . 37
12
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
2/43
Doc ID 15327 Rev 2
UM0670
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
LED values for different output currents . . . . . . . . . . . . . . . . . . . . . .
Output LED current adjustment on the demonstration board . . . . . .
STEVAL-ILL013V1 demonstration board bill of material . . . . . . . . .
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Doc ID 15327 Rev 2
3/43
UM0670
List of figures
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Figure 30.
Figure 31.
Figure 32.
Figure 33.
Figure 34.
Figure 35.
Figure 36.
Figure 37.
Figure 38.
Figure 39.
Figure 40.
Figure 41.
Figure 42.
Figure 43.
STEVAL-ILL013V1 demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
STEVAL-ILL013V1 block schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
High PF boost converter design concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Modified buck converter with dimming design concept. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
STEVAL-ILL013V1 with PWM module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
High PFC boost converter with the L6562A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Modified buck converter with the L6562A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Efficiency over the whole input voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Power factor for wide input voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Detailed power factor for wide input voltage range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Total harmonic distortion for wide input voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Output LED current dimming capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Output LED current waveform (I
LED
= 350 mA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Output LED current for different LED voltages (I
LED
= 350 mA). . . . . . . . . . . . . . . . . . . . . 20
Output LED current waveforms (I
LED
= 700 mA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Output LED current for different LED voltage (I
LED
= 700 mA). . . . . . . . . . . . . . . . . . . . . . 21
Output LED current waveform (I
LED
= 1000 mA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Output LED current for different LED voltage (I
LED
= 1000 mA). . . . . . . . . . . . . . . . . . . . . 22
Power MOSFET turn ON and OFF measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
LED current ripple for the 100 nF output capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
EN61000-3-2 analysis for LED current of 350 mA and V
IN
from 85 V to 160 VAC . . . . . . 23
EN61000-3-2 analysis for LED current of 350 mA and V
IN
from 180 V to 265 VAC . . . . . 24
EN61000-3-2 analysis for LED current of 700 mA and V
IN
from 85 V to 160 VAC . . . . . . 24
EN61000-3-2 analysis for LED current of 700 mA and V
IN
from 180 V to 265 VAC . . . . . 24
EN61000-3-2 analysis for LED current of 1000 mA and V
IN
from 85 V to 160 VAC . . . . . 25
EN61000-3-2 analysis for LED current of 1000 mA and V
IN
from 180 V to 265 VAC . . . . 25
Average limit measurement from 150 kHz to 30 MHz (I
LED
= 350 mA) . . . . . . . . . . . . . . . 26
Quasi-peak limit measurement from 9 kHz to 150 kHz (I
LED
= 350 mA) . . . . . . . . . . . . . . 26
Quasi-peak limit measurement from 150 kHz to 30 MHz (I
LED
= 350 mA). . . . . . . . . . . . . 27
Average limit measurement from 150 kHz to 30 MHz (I
LED
= 700 mA) . . . . . . . . . . . . . . . 27
Quasi-peak limit measurement from 9 kHz to 150 kHz (I
LED
= 700 mA) . . . . . . . . . . . . . . 28
Quasi-peak limit measurement from 150 kHz to 30 MHz (I
LED
= 700 mA). . . . . . . . . . . . . 28
Average limit measurement from 150 kHz to 30 MHz (I
LED
= 1000 mA) . . . . . . . . . . . . . . 29
Quasi-peak limit measurement from 9 kHz to 150 kHz (I
LED
= 1000 mA) . . . . . . . . . . . . . 29
Quasi-peak limit measurement from 150 kHz to 30 MHz (I
LED
= 1000 mA). . . . . . . . . . . . 30
Average limit measurement from 150 kHz to 30 MHz (I
LED
= 0 mA) . . . . . . . . . . . . . . . . . 30
Quasi-peak limit measurement from 9 kHz to 150 kHz (I
LED
= 0 mA) . . . . . . . . . . . . . . . . 31
Quasi-peak limit measurement from 150 kHz to 30 MHz (I
LED
= 0 mA) . . . . . . . . . . . . . . . 31
Proper startup circuit design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Proper startup using diode D104 and capacitor C110 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Improper startup without using diode D104 and capacitor C110 . . . . . . . . . . . . . . . . . . . . 33
Design improvement allowing zero dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Voltage on capacitor C110 and output bus voltage of 400 V . . . . . . . . . . . . . . . . . . . . . . . 35
Doc ID 15327 Rev 2
4/43
Getting started
UM0670
2
Getting started
This section is intended to help designers begin evaluating the board quickly, describing
how the board should be connected with the load and how the jumpers adjust the output
LED current.
As mentioned in the introduction, the board has a nominal output power of 80 W and the
output LED current can be set to 350 mA, 700 mA or 1 A. The LEDs are connected to one
string. Basically, this means if the LED current is set to 350 mA, then the LED voltage should
be approximately 228 V in order to provide output power of 80 W. If the LED current is set to
700 mA, then the LED voltage should be around 114 V. Finally, if the LED current is set
to 1 A, then the LED voltage should be about 80 V. Assuming that a high brightness LED
has (typically) a 3.5 V forward voltage drop, the number of LEDs for the 350 mA output
current is 65, for the 700 mA output current it is 32 and for the output current of 1 A it is 23
(see
Table 1).
Of course, designers must recalculate the number of LEDs in cases where
the LED has a forward voltage drop other than 3.5 V. If the output LED voltage is different
than that given in
Table 1,
output LED current precision will be influenced so is
recommended that the total forward voltage drop across all the LEDs is as close as possible
to the calculated output voltages shown in
Table 1.
Connect the LED string to the board using connector J2 or J3, being careful to observe the
correct LED polarity (anode + and cathode –). Set the output LED current to 350 mA, 700
mA or 1 A, based on how many LEDs are connected to the output. The output LED current
is set using jumpers JP1, JP2, JP3 and JP4, in accordance with the connection settings
specified in
Table 2.
It is not necessary to connect a dimming module with a PWM signal,
because if the module is not used the LED brightness is set to maximum level (100%
brightness). Finally, connect an input voltage to the demonstration board between 88 VAC
and 265 VAC, and the LEDs begin illuminating.
Note:
The LEDs cannot be connected during operation, when the input voltage is connected to the
demonstration
board. This is because in this case the output capacitor C208 = 0.47 µF is
charged to 400 V and can cause uncontrolled peak LED current.
Table 1.
LED values for different output currents
Output LED voltage [V]
228
114
80
Number of LEDs for forward
voltage drop 3.5 V
65
32
23
Output LED current [mA]
350
700
1000
Table 2.
Output LED current adjustment on the demonstration board
350 mA
Not connected
Not connected
Not connected
Not connected
700 mA
Connected
Connected
Not connected
Not connected
1000 mA
Not connected
Not connected
Connected
Connected
Jumper
JP1
JP2
JP3
JP4
5/43
Doc ID 15327 Rev 2
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