AN2259 APPLICATION NOTE
High intensity LED driver using the L5970D/L5973D
Introduction
H igh brightness LEDs are becoming a prominent source of light and often have better efficiency and reliability than conventional light sources. While LEDs can operate from an energy source as simple as a battery and resistor, most applications require an efficient energy source not only for the reduction of losses, but also to maintain the brightness of the LED itself. For applications that are powered from low voltage AC sources typically used in landscape lighting or low voltage DC sources that may be used in automotive applications or to meet safety requirements, high efficiency DC-DC converters configured for constant output current provide a high efficiency driver that can operate over a relatively wide range of input voltages to drive series strings of one to several LEDs
This application note describes a DC-DC converter circuit that can easily be configured to drive LEDs at several different output currents and can be configured for either AC or DC input. The circuit uses the L5973D monolithic step down converter configured to drive a series string of LEDs in a constant current mode.
L5970D is a step down monolithic power switching regulator capable of delivering 1A while the L5973D is able to deliver 2A at output voltages from 1.25V to 35V. Both devices use internal PC hannel D-MOS transistors (with typical RDS(on) of 250m) as the switching element to minimize the size of external components. An internal oscillator fixes the switching frequency at 250kHz. The brightness of the LED (Light Emitting Diode), or light intensity as measured in Lumens, is proportional to the forward current flowing through the LED. Since the forward voltage drop of the LED can vary from device to device it is important to drive the LEDs with a constant current driver to be able to get good matching of the light output, especially when they are located side by side where variations in light intensity are quickly noticed. A typical way to drive LEDs in the constant current mode is to use a DC-DC converter configured to give a constant current output. The circuit shown in Figure 7. uses the L5973D in a constant current configuration to drive LEDs
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Figure 1. Board Layout
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Contents
1 2 3 4 5 6 7 DESCRIPTION OF BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 INPUT CAPACITOR SELECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 CURRENT FEEDBACK LOOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 INDUCTOR SELECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 BOARD LAYOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 REFERENCE DESIGN VERSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
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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. Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Current feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Ripple Current (One 1W LED). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Ripple current (One 5W LED) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Top side of Board (not in scale) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Bottom side of Board (not in scale) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Board Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 12Vac Input 1W LED Driver Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . 18 12Vac Input 3W LED Driver Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . 20 12Vac Input 5W LED Driver Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . 22 6 to 12Vdc Input 1W LED Driver Schematic . . . . . . . . . . . . . . . . . . . . . . . 24 6 to 12Vdc Input 3W LED Driver Schematic . . . . . . . . . . . . . . . . . . . . . . . 26 6 to 12Vdc Input 5W LED Driver Schematic . . . . . . . . . . . . . . . . . . . . . . . 28 6 to 24Vdc Input 1W LED Driver Schematic . . . . . . . . . . . . . . . . . . . . . . . 30 6 to 24Vdc Input 3W LED Driver Schematic . . . . . . . . . . . . . . . . . . . . . . . 32 6 to 24Vdc Input 5W LED Driver Schematic . . . . . . . . . . . . . . . . . . . . . . . 34
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Tables
Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Bill of Matarials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Components Changes For Different Configuration . . . . . . . . . . . . . . . . . . 16 12Vac Input 1W LED Driver Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . 19 12Vac Input 3W LED Driver Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . 21 12Vac Input 5W LED Driver Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . 23 6 to 12Vdc Input 1W LED Driver Bill of Materials . . . . . . . . . . . . . . . . . . . 25 6 to 12Vdc Input 3W LED Driver Bill of Materials . . . . . . . . . . . . . . . . . . . 27 6 to 12Vdc Input 5W LED Driver Bill of Materials . . . . . . . . . . . . . . . . . . . 29 6 to 24Vdc Input 1W LED Driver Bill of Materials . . . . . . . . . . . . . . . . . . . 31 6 to 24Vdc Input 3W LED Driver Bill of Materials . . . . . . . . . . . . . . . . . . . 33 6 to 24Vdc Input 5W LED Driver Bill of Materials . . . . . . . . . . . . . . . . . . . 35
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1 DESCRIPTION OF BOARD
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1
DESCRIPTION OF BOARD
The evaluation board shown in Figure 1. was designed so that it can be configured to accept several different input voltages that are common for automotive and lighting applications. The most common input voltages are 12Vac, 12Vdc (for automotive) and 24Vdc. The board also allows the user to select the output current using the jumpers J2 and J4 on the board without having to change any components on the evaluation board. The standard configuration of the board includes a full wave bridge rectifier that is required for an AC input
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2 INPUT CAPACITOR SELECTION
2
INPUT CAPACITOR SELECTION
For DC input, the input capacitor, C1, is selected based on its ripple current rating for the capacitor. The ripple current is calculated based on its duty cycle as outlined below.
D=
W here D = duty cycle Vo = output voltage Vin = input voltage
Vo Vin
The RMS current through the capacitor therefore is:
Ir i p p l e = Io D -
= efficiency
2 D2 D 2 +2
For an AC input voltage, the input capacitor is selected primarily to have enough capacity to supply the LED between the peaks of the AC input. The capacitor must be selected so that the minimum voltage at the input to the L5973D is maintained during each half cycle of the AC input.
Vpeak = 2 Vin
If the application is driving only one LED, the Vmin is determined by the minimum operating voltage specification for the L5973D (4.4V). When driving more than one LED in series, the minimum input voltage is determined by the output voltage and the minimum differential input to output voltage for the regulator (the drop out voltage). In this case Vmin = (x * Vf) + (Iout * Rsense) + V DO W here: x = number of LED in series Vf = forward voltage of one LED Io = LED drive current VDO = Drop out voltage The capacitor can then be selected using the equation:
C=
5 10-3 Io Vo 1 1 ( Vpeak 2 - V min 2 ) 2 2
The ripple current rating will have two parts where in the low frequency range, the capacitor will be charged by 120Hz while at the high frequency range the capacitor is discharged by 250kHz. For the low frequency part, it is approximately the same as the input RMS current and the power factor is approximately 0.7 for a full wave rectifier.
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2 INPUT CAPACITOR SELECTION
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Iin =
Io Vo Vin 0.7
For the high frequency part (ignoring output current ripple), we have:
Iripple = Dav -
w here Dav is the average duty cycle.
2 Da v 2 Da v 2 + 2 Io
We will use the average duty cycle assuming that the voltage on the capacitor changes from the peak to the minimum voltage linearly.
Dav =
Vo Vav
Vav =
Vpeak + V min 2
Iripple = Dav -
2 Dav 2 Dav 2 + 2 Io
The equivalent series resistance of an aluminum capacitor has different frequency characteristics. There is a coefficient associated with different frequencies. Typically, for 120Hz, Kfl=1; for frequency greater than 10 kHz, Kfh=1.5.
Icap =
Iin Kfl
2
+
Iripple Kfh
2
Therefore, the ripple current rating of the capacitor has to be greater than Icap
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3 CURRENT FEEDBACK LOOP
3
CURRENT FEEDBACK LOOP
To drive LEDs in a constant current mode, the feedback for the regulator is taken by sensing the voltage drop across the current sense resistor, Rs, as shown in Figure 2. The voltage divider between the sense resistor and the feedback pin (R1 and R2) scales the voltage at the feedback pin so that it equals the internal reference voltage at the desired current level. Figure 2. Current feedback
In order to get Io = 350 mA, the values of R1, R2 and Rs are selected based on the following values. Vref = 3.3V ; Vfb = 1.235V ; Ifb_bias = 2.5 10-6 A ; Rs=0.68 Vsense=Rs.Io U sing the superposition method:
Vfb = Vref
R2 R1 R1 R 2 + Vsense + Ifb _ bias R1 + R 2 R1 + R 2 R1 + R 2
R2 - Ifb _ bias R 2 R1 Io = Vsense Rs
Vsense = Vfb - ( Vref - Vfb)
Io =
Vfb - (Vref - Vfb)
R2 - Ifb _ bias R 2 R1 Rs
Since Vref and Vfb come from same band gap, they are directly correlated. K=Vref/Vfb=2.672. Therefore, the equation can be simplified to:
1 - (K - 1)
Io =
R2 Vfb - Ifb _ bias R 2 R1 Rs
For 350mA output the selected values are: R1 = 2.74k, R2 =1.30k and Rs = 0.68.
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3 CURRENT FEEDBACK LOOP
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For an output current of 700mA the value of Rs would be 0.34. If R1 and R2 are small enough, the effect of the bias current can be ignored. On the evaluation board, the value of Rs is selected by jumpers J2 and J4. When both J2 and J4 are open, the output current is set to 350mA. Inserting each jumper connects a 0.68 resistor in parallel with the 0.68 Rs. With J2 shorted, the output current will be set to 700mA and the output current becomes 1A with both J2 and J4 shorted.
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4 INDUCTOR SELECTION
4
INDUCTOR SELECTION
The output inductor is selected to limit the ripple current in the LEDs. For example, for a given DC input voltage and an output current of 350mA, the peak current can be fixed to 500mA. This implies a Imax = 300mA. For an output current of 700mA, the peak current can be fixed to1000mA. This implies a Imax= 600mA Lmin= Figure 3.
Vin - Vo Ton Im ax
Ripple Current (One 1W LED)
Figure 3. shows the ripple current measured with one 1W LED (warm white) at the output with 12Vac input. The measured ripple current is 180mA.
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4 INDUCTOR SELECTION
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Figure 4.
Ripple current (One 5W LED)
Figure 4. shows the ripple current driving one 5W LED at 1.05 A from a 12Vac input. The input current is 269mA.
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5 BOARD LAYOUT
5
BOARD LAYOUT
The layout for the evaluation board is shown below in Figure 5. and Figure 6. The area within the circle in the center of the board illustrates the required area for the final application. The components outside of the circle are connectors for convenience and the auxiliary devices that allow the current to be selected on this board without changing the resistor values. Obviously the final application would use a single resistor for RS that is optimized for the application. Figure 5. Top side of Board (not in scale)
Figure 6.
Bottom side of Board (not in scale)
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5 BOARD LAYOUT
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Board Schematic
Figure 7.
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Table 1.
Qty 1 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1
5 BOARD LAYOUT
Bill of Matarials
Part Description Mfg P/N Mf g Panasonic Geometry Mounting Radial TH S MD S MD S MD S MD STPS2L40U M KDSN1.5/2 22-28-8020 535676-5 22-28-8020 DO3316P-683 MMB T 3 9 0 6 STMicroelectronics Phoenix Contact Molex Tyco Molex Coilcraft STMicroelectronics SOT23 2010 2010 2010 0805 0805 0805 0805 L5973D STMicroelectronics SO8 6 Pin SM B SMD TH TH TH TH S MD SMD S MD S MD S MD S MD S MD S MD S MD S MD
Par t Reference C1 C2 C3 C4 C5 D2 D4 D5 D6 D7 J1 J2 J3 J4 L1 Q1 Rs Rs 2 Rs 3 R1 R2 R3 R4 U1
1200uF/35V electrolytic EEU-FC1V22L 220pF/50V ceramic 22nF/50V ceramic 22nF/50V ceramic 4.7nF/50V ceramic Low Drop Power Schottky Rectifier Phoenix 2 Pin Connector Current Select Jumper Stackable Receptacle Current Select Jumper Inductor PNP Transistor 0.68ohms 1% 1/4W 0.68ohms 1% 1/4W 0.68ohms 1% 1/4W 2.74kohms 1% 1/8W 1.30kohms 1% 1/8W 4.7kohms 5% 1/8W 240kohms 5% 1/8W Step-down controller
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6 REFERENCE DESIGN VERSIONS
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6
REFERENCE DESIGN VERSIONS
The evaluation board is designed to display the full functionality of L5973D as a LED driver to drive one to three 1W, 3W as well as 5W LEDs at 12Vac input. The components selected for the demo board are optimized for 5W LED driver application. Based on this circuit, there are nine different configurations with different input voltages and output power levels that could be derived by making minor components changes to the evaluation board. Table 1. shows the component changes needed in order to obtain each configuration. The final schematics and bill of materials for each configuration are shown in the subsequent pages. The 6 to 12 Vdc input configuration was designed for automotive applications that must survive a reverse battery condition. In this case one of the rectifiers remains on the board to provide protection against reversing the power supply leads. Table 2.
12Vac 1W LED 12Vac 3W LED 12Vac 5W LED 6-12Vdc 1W LED 6-12Vdc 3W LED 6-12Vdc 5W LED 6-24Vdc 1W LED 6-24Vdc 3W LED 6-24Vdc 5W LED
Components Changes For Different Configuration
U1 L5970D L5973D L5973D L5970D L5973D L5973D L5970D L5973D L5973D D4 STPS1L40A STPS2L40U STPS2L40U Not used Not used Not used Not used Not used Not used D5 STPS1L40A STPS2L40U STPS2L40U Not used Not used Not used Not used Not used Not used D6 STPS1L40A STPS2L40U STPS2L40U STPS1L40A STPS2L40U STPS2L40U Jumper wire Jumper wire Jumper wire D7 STPS1L40A STPS2L40U STPS2L40U Jum per wire Jum per wire Jum per wire Jum per wire Jum per wire Jum per wire
LED Driver
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Table 2. (Continued)
C1 680uF/35V 1200uF/35V 1200uF/35V 27uF/50V 68uF/50V 100uF/50V 22uF/35V 68uF/35V 100uF/35V R2 1.30k 1% 1.33k 1% 1.30k 1% 1.30k 1% 1.33k 1% 1.30k 1% 1.30k 1% 1.33k 1% 1.30k 1% Rs 0.68 0.33 0.24 0.68 0.33 0.24 0.68 0.33 0.24
6 REFERENCE DESIGN VERSIONS
L1 47uH 33uH 68uH 47uH 33uH 68uH 100uH 100uH 100uH
D2 STPS1L40A STPS2L40U STPS2L40U STPS1L40A STPS2L40U STPS2L40U STPS1L40A STPS2L40U STPS2L40U
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2
2
1
STPS1L40A + 1/ 8W 4 I NH C3 3 2 2 2 C2 220pf 22nf 7 D5 2 STPS1L40A 1 1 GN D C OMP FB 5 1 1
STPS1L40A
C1 680uF 35V SY N C VREF 2 2 6 1 2. 74K 2
1
1
1
R4 240K 1/ 8W 1 MMBT3906 1 Q1 3 2 C5 4. 7nf
C4 1/ 8W 22nf
1
2
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Figure 8.
U1 L1 8 VCC R1 OUT D6 1 47uH
L5970D J3 1 LED+ D2 STPS1L40A 1 LEDR2 1 J4
6 REFERENCE DESIGN VERSIONS
J1 D4
Vin-
D7 STPS1L40A
Vin+
J2
R3 4. 7K 1/ 8W
1. 30K 2 Rs 0. 68 1/ 4W
12Vac Input 1W LED Driver Schematic
Note: Minimum input voltage for 1 LED : 5VAC Minimum input voltage for 2 LEDs : 7.5VAC Minimum input voltage for 3 LEDs : 10VAC
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Table 3.
Qt y 1 1 2 1 5 1 1 1 1 1 1 1 1
6 REFERENCE DESIGN VERSIONS
12Vac Input 1W LED Driver Bill of Materials
Part Description 680uF/35V Electrolytic 220pF/50V Ceramic 22nF/50V Ceramic 4.7nF/50V Ceramic Schottky Diode 1A/40V 47uH Inductor PNP Transistor 0.68 Ohm 1% 2.74k 1% 1.30k 1% 4.7k 5% 240k 5% Step-down controller L5970D STMicroelectronics STPS1L40A DO3308P-473 MMB T 3 9 0 6 STMicroelectronics Coilcraft STMicroelectronics SMA Mfg P/N EEU-FC1V681 Mf g Panasonic Geometry Radial Mtg TH SM D SM D SM D SM D
Reference C1 C2 C3, C4 C5 D2, D4, D5, D6, D7 L1 Q1 Rs R1 R2 R3 R4 U1
9.4mmx12.95mm SM D SOT-23 1206 0805 0805 0805 0805 0 S O8 SM D SM D SM D SM D SM D SM D SM D
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2
2
1
STPS2L40U + 1/ 8W 4 I NH 1 C3 3 2 2 2 C2 220pf 22nf 7 D5 2 STPS2L40U 1 1 R4 240K 1/ 8W MMBT3906 1 Q1 3 2 C5 4. 7nf 1 GN D C OMP FB 5 1 1 D2
STPS2L40U
C1 1200uF 35V SY N C 2 2 VR EF 1 6 2. 74K 2
1
1
22nf
1
2
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Figure 9.
U1 L1 8 VC C R1 33uH OU T D6 1
L5973D J3 1 LED +
J1 D4
6 REFERENCE DESIGN VERSIONS
Vin-
STPS2L40U 1
J4
LED R2 1 R3 4. 7K 1/ 8W 1. 33K 2 C 4 1/ 8W
D7 STPS2L40U
Vin+
J2
12Vac Input 3W LED Driver Schematic
Rs 0. 33 1/ 2W
N o te :
Minimum input voltage for 1 LED : 5VAC Minimum input voltage for 2 LEDs : 8VAC Minimum input voltage for 3 LEDs : 10.5VAC
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Table 4.
Qt y 1 1 2 1 5 1 1 1 1 1 1 1 1
6 REFERENCE DESIGN VERSIONS
12Vac Input 3W LED Driver Bill of Materials
Part Description 1200uF/35V Electrolytic 220pF/50V Ceramic 22nF/50V Ceramic 4.7nF/50V Ceramic Schottky Diode 2A/40V 33uH Inductor PNP Transistor 0.33 Ohm 1% 2.74k 1% 1.33k 1% 4.7k 5% 240k 5% Step-down controller L5973D STM icroelectronics STPS2L40U DO3308P-333 M MBT3906 CRL2010-FWR330E STM icroelectronics Coilcraft STM icroelectronics Bourns SMB Mfg P/N EEUFC1V122L Mf g Panasonic G eometry Radial Mt g TH SMD SMD SMD S MD
Reference C1 C2 C3, C4 C5 D2, D4, D5, D6, D7 L1 Q1 Rs R1 R2 R3 R4 U1
9.4mm x12.95mm SMD SOT-23 2010 0805 0805 0805 0805 SO 8 SMD S MD S MD S MD S MD S MD SMD
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2
1
INH
GND
1
3
1
R3 4 .7 k 1 /8 W 2
Vin +
D7 S TP S 2 H 1 0 0 U
D5 S TP S 2 H 1 0 0 U
C2 2 20 pf 7
J2 C ON 1 1
R4 2 40 k 1 /8 W
C4 22 nf
1.3 0 K 1/8 W
1
2
Figure 10. 12Vac Input 5W LED Driver Schematic
Q1 MMBT39 06 3
2 C5 4.7n f
Note: Minimum input voltage for 1 LED: 5Vac Minimum input voltage for 2 LEDs: 8Vac Minimum input voltage for 3 LEDs: 10.5Vac
1
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U1
Vcc
L 59 73 D OU T VR EF FB 5 2 .7 4K 1 /8 W 6 R1 1 L1 DO3316P-683 6 8 uH D2 S TP S 2 L 4 0 U 1 LED R2 C ON 1 J3 1 LED + C ON 1 J4
6 REFERENCE DESIGN VERSIONS
J1 C ON 1 8 VC C S YNC C OMP 2 4 C3 22 nF D6 S TP S 2 H 1 0 0 U
+
Vin -
D4 S TP S 2 H 1 0 0 U
C1 1 2 00 uF 3 5V
Rs 0 .24 Ohm 1 /4W
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Table 5.
Qt y 1 1 2 1 5 1 1 1 1 1 1 1 1
6 REFERENCE DESIGN VERSIONS
12Vac Input 5W LED Driver Bill of Materials
Part Description 1200uF/35V Electrolytic 220pF/50V Ceramic 22nF/50V Ceramic 4.7nF/50V Ceramic Schottky Diode 2A/40V 68uH Inductor PNP Transistor 0.24 Ohm 1% 2.74k 1% 1.30k 1% 4.7k 5% 240k 5% Step-down controller L5973D STM icroelectronics STPS2L40U DO3316P-683 M MBT3906 CRL2010-FWR240E STM icroelectronics Coilcraft STM icroelectronics Bourns SMB Mfg P/N EEUFC1V122L Mf g Panasonic G eometry Radial Mt g TH SMD SMD SMD S MD
Reference C1 C2 C3, C4 C5 D2, D4, D5, D6, D7 L1 Q1 Rs R1 R2 R3 R4 U1
9.4mm x12.95mm SMD SOT-23 2010 0805 0805 0805 0805 SO 8 SMD S MD S MD S MD S MD S MD SMD
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C1 27uF 50V 2 SY NC 1/ 8W 4 INH C3 3 2 C2 220pf 22nf 7 GND COMP FB 5 VREF 1 6 2.74K 2 +
2
1
J1 1 1 VinMMBT3906 1 Q1 3 2 1 2
2
R4 240K 1/ 8W 1
Figure 11. 6 to 12Vdc Input 1W LED Driver Schematic
22nf
1
C5 4.7nf
2
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U1 J2 1 8 VC C R1 OUT 1 47uH LED+ D2 STPS1L40A 1 LEDR2 1 R3 4. 7K 1/ 8W 1.30K 2 C4 1/ 8W J4 Vin+ STPS1L40A 1 2 D6 L5970D L1 1 J3 D7 Jumper Rs 0.68 1/4W
6 REFERENCE DESIGN VERSIONS
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Table 6.
Qt y 1 1 2 1 2 1 1 1 1 1 1 1 1 1
6 REFERENCE DESIGN VERSIONS
6 to 12Vdc Input 1W LED Driver Bill of Materials
Part Description 27uF/50V Electrolytic 220pF/50V Ceramic 22nF/50V Ceramic 4.7nF/50V Ceramic Schottky Diode 1A/40V Jumper at D7 position 47uH Inductor PNP Transistor 0.68 Ohm 1% 2.74k 1% 1.30k 5% 4.7k 5% 240k 5% Step-down controller L5970D STM icroelectronics DO3308P-473 M MBT3906 Coilcraft STM icroelectronics STPS1L40A STM icroelectronics SMA Mfg P/N EEUFC1H270 Mf g Panasonic G eometry Radial Mt g TH SMD SMD SMD S MD SMD 9.4mm x12.95mm SMD SOT-23 1206 0805 0805 0805 0805 SO 8 SMD S MD S MD S MD S MD S MD SMD
Reference C1 C2 C3, C4 C5 D2, D6 D7 L1 Q1 Rs R1 R2 R3 R4 U1
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C6 68uF 50V 2 SY N C C OMP INH 3 7 FB 5 VR EF 1 4 C3 2 C2 220pf 22nf GN D 6 +
1/ 8W
2
1
J1 1 1 VinMMBT3906 1 Q1 3 1 2
2
R4 240K 1/ 8W 1
Figure 12. 6 to 12Vdc Input 3W LED Driver Schematic
22nf
1
2 C5 4. 7nf
2
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U1 J2 1 VC C R1 OU T Vin+ STPS2L40U 2. 74K 2 1 2 8 1 33uH LED + D2 STPS2L40U 1 LE D R2 1 R3 4. 7K 1/ 8W 1. 33K 2 C 4 1/ 8W J4 D6 L5973D L1 1 J3 D 7 Jumper Rs 0. 33 1/ 2W
6 REFERENCE DESIGN VERSIONS
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Table 7.
Qt y 1 1 2 1 2 1 1 1 1 1 1 1 1 1
6 REFERENCE DESIGN VERSIONS
6 to 12Vdc Input 3W LED Driver Bill of Materials
Part Description 68uF/50V Electrolytic 220pF/50V Ceramic 22nF/50V Ceramic 4.7nF/50V Ceramic Schottky Diode 2A/40V Jumper at D7 position 33uH Inductor PNP Transistor 0.33 Ohm 1% 2.74k 1% 1.33k 1% 4.7k 5% 240k 5% Step-down controller L5973D STM icroelectronics DO3308P-333 M MBT3906 CRL2010-FWR330E Coilcraft STM icroelectronics Bourns STPS2L40U STM icroelectronics Mfg P/N EEUFC1H680 Mf g Panasonic G eometry R adial D8mm 805 805 805 SMB Mt g TH S MD S MD S MD S MD SMD 9.4mm x12.95mm SMD SOT-23 2010 0805 0805 0805 0805 SO 8 SMD S MD S MD S MD S MD S MD SMD
Reference C1 C2 C3, C4 C5 D2, D6 D7 L1 Q1 Rs R1 R2 R3 R4 U1
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INH GND
+
C1 1 00u F 50V 2 S YN C C O MP 3 7 FB 5 4 VR EF
2 .7 4 K 1/8W 1
2
1
D 7 Jum p e r 1 2
R3 4 .7 k 1/8W
2
Vin 1
1 .3 0 K 1/8W R4 240 k 1 /8 W 1 2 C4 22n F
C ON 1
2
1
3
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D6 1
Vc c
6 REFERENCE DESIGN VERSIONS
Vin + 8 VC C 6 R1 OU T 1 S TP S 2 H1 0 0 U
J2
U1
L5 9 73 D L 1 DO3316P-683 68 u H D2 S TPS 2 L 4 0 U 1 LED R2 J3 1 LED +
C ON 1
J4
C2 220 p F
C3 2 2n F
J1
Figure 13. 6 to 12Vdc Input 5W LED Driver Schematic
Rs 0.2 4 Oh m 1/4 W Q1 MMB T3 9 0 6
C5 4 .7 n F
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Table 8.
Qt y 1 1 2 1 2 1 1 1 1 1 1 1 1 1
6 REFERENCE DESIGN VERSIONS
6 to 12Vdc Input 5W LED Driver Bill of Materials
Part Description 100uF/50V Electrolytic 220pF/50V Ceramic 22nF/50V Ceramic 4.7nF/50V Ceramic Schottky Diode 2A/40V Jumper at D7 position 68uH Inductor PNP Transistor 0.24 Ohm 1% 2.74k 1% 1.30k 1% 4.7k 5% 240k 5% Step-down controller L5973D STM icroelectronics DO3316P-683 M MBT3906 CRL2010-FWR240E Coilcraft STM icroelectronics Bourns STPS2L40U STM icroelectronics Mfg P/N EEUFC1H101 Mf g Panasonic G eometry R adial D8mm 805 805 805 SMB Mt g TH S MD S MD S MD S MD SMD 9.4mm x12.95mm SMD SOT-23 2010 0805 0805 0805 0805 SO 8 SMD S MD S MD S MD S MD S MD SMD
Reference C1 C2 C3, C4 C5 D2, D6 D7 L1 Q1 Rs R1 R2 R3 R4 U1
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C1 22u F 35V SY N C 1/ 8W 4 INH C3 3 2 C2 220pf 22nf 7 GN D C O MP FB 5 VR E F + 2 2 1 6 2. 74 K 2
24 V
1
J1 1 1 2
2
Vin MMBT3 906 1 Q1 3 2 1
Figure 14. 6 to 24Vdc Input 1W LED Driver Schematic
R4 24 0K 1/ 8W
22nf
1
C5 4. 7n f
2
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D 6 Jumper1 1 8 VC C R1 OU T 1 1 00uH LED + D2 STPS 1L40A 1 LE D R2 1 R3 4. 7 K 1/ 8 W 1. 30K 2 C 4 1 / 8W J4 2 U1 L 5970D L1 1 J3 D 7 Jumper Rs 0 . 68 1 / 4W
6 REFERENCE DESIGN VERSIONS
J2
1
Vin +
1
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Table 9.
Qt y 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1
6 REFERENCE DESIGN VERSIONS
6 to 24Vdc Input 1W LED Driver Bill of Materials
Part Description 22uF/35V Electrolytic 220pF/50V Ceramic 22nF/50V Ceramic 4.7nF/50V Ceramic Schottky Diode 1A/40V Jumper at D7 position Jumper at D6 position 100uH Inductor DO3308P-104 PNP Transistor 0.68 Ohm 1% 2.74k 1% 1.30k 1% 4.7k 5% 240k 5% Step-down controller L5970D STMicroelectronics MM BT3906 Coilcraft STMicroelectronics 9 . 4 mm x 12.95mm SOT-23 1206 0805 0805 0805 0805 SO8 STPS1L40A STMicroelectronics SMA Mfg P/N EEUFC1H220 Mf g Panasonic Geometry Radial Mtg TH SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D
Reference C1 C2 C3, C4 C5 D2 D7 D6 L1 Q1 Rs R1 R2 R3 R4 U1
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C1 68 uF 35 V SY N C 1/ 8W 4 INH C3 3 2 C2 22 0pf 22 nf 7 GN D C OMP FB 5 VR E F + 2 2 1 6
2 4V
1
J1 2 1 1 2
Vin MMBT3 906 1 Q1 3 2 1
Figure 15. 6 to 24Vdc Input 3W LED Driver Schematic
R4 240K 1/ 8W
2 2nf
1
C5 4. 7 nf
2
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D 6 Jumper L1 1 VC C R1 2. 74K 2 OU T 2 8 1 10 0uH LE D + D2 STP S2L40 U 1 L ED R2 1 R3 4. 7K 1/ 8W 1 . 33K 2 C 4 1/ 8 W J4 1 U1 L5 973D J3 D7 Jumper Rs 0 . 33 1 / 2W
J2
6 REFERENCE DESIGN VERSIONS
1
V in+
1
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Table 10.
Qt y 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1
6 REFERENCE DESIGN VERSIONS
6 to 24Vdc Input 3W LED Driver Bill of Materials
Part Description 68uF/35V Electrolytic 220pF/50V Ceramic 22nF/50V Ceramic 4.7nF/50V Ceramic Schottky Diode 2A/40V Jumper at D6 position Jumper at D7 position 100uH Inductor DO3316P-104 PNP Transistor 0.33 Ohm 1% 2.74k 1% 1.33k 1% 4.7k 5% 240k 5% Step-down controller L5973D STMicroelectronics MM BT3906 CRL2010-FWR330E Coilcraft STMicroelectronics Bourns 9 . 4 mm x 12.95mm SOT-23 2010 0805 0805 0805 0805 SO8 STPS2L40U STMicroelectronics SMB Mfg P/N EEUFC1V680 Mf g Panasonic Geometry Radial Mtg TH SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D
Reference C1 C2 C3, C4 C5 D2 D6 D7 L1 Q1 Rs R1 R2 R3 R4 U1
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INH
G ND
+
C1 1 00 uF 35 V 2 S YN C C O MP 3 7 FB 5 4 VR E F
2 .7 4 K 1/8 W 1
2
1
D 7 Jum p e r 1 2
R3 4 .7 k 1 /8W
2
Vi n 1
1 .3 0 K 1 /8W R4 24 0k 1 /8 W 1 2 C4 22n F
C ON 1
2
1
3
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U1
Vcc
6 REFERENCE DESIGN VERSIONS
L 59 73 D OU T 6 R1 1
Vi n + 1 VC C 8
J2
L 1 DO3316P-104 1 10 0u H D2 S TP S 2 L 4 0 U 1
J3 LE D
1
D 6 Jum p e r 2
C ON 1
J4 LE R2
C2 22 0pF
C3 22n F
J1
Figure 16. 6 to 24Vdc Input 5W LED Driver Schematic
Rs 0 .2 4 o 1 /4 W Q1 MMB T 3 9 0 6 C5 4 .7 n F
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Table 11.
Qt y 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1
6 REFERENCE DESIGN VERSIONS
6 to 24Vdc Input 5W LED Driver Bill of Materials
Part Description 100uF/35V Electrolytic 220pF/50V Ceramic 22nF/50V Ceramic 4.7nF/50V Ceramic Schottky Diode 2A/40V Jumper at D6 position Jumper at D7 position 100uH Inductor DO3316P-104 PNP Transistor 0.24 Ohm 1% 2.74k 1% 1.30k 1% 4.7k 5% 240k 5% Step-down controller L5973D STMicroelectronics MM BT3906 CRL2010-FWR240E Coilcraft STMicroelectronics Bourns 9 . 4 mm x 12.95mm SOT-23 2010 0805 0805 0805 0805 SO8 STPS2L40U STMicroelectronics SMB Mfg P/N EEUFC1V101 Mf g Panasonic Geometry Radial Mtg TH SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D SM D
Reference C1 C2 C3, C4 C5 D2 D6 D7 L1 Q1 Rs R1 R2 R3 R4 U1
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7 REVISION HISTORY
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7
REVISION HISTORY
Date 04-Nov-2005
Revision 1.0 First edition
Changes
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7 REVISION HISTORY
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7 REVISION HISTORY
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