DC1160A - Demo Manual

DEMO MANUAL DC1160
LT3518: Full-Featured
LED Driver with 2.3A
Switch Current
DESCRIPTION
Demonstration circuit 1160 is a full-featured LED driver
with 2.3A switch current featuring the LT®3518. The board
is optimized to drive a 330mA LED string with a total LED
voltage between the input voltage and 40V in a boost topology. The high input voltage range, high efficiency low
side internal 2.3A NPN power switch, low voltage floating
current sense amplifier, soft-start, high side PMOS PWM
gate driver, high PWM dimming ratio, overvoltage protection, shutdown control pin, analog LED current dimming
control, and externally programmable switching frequency
(with sync) make the LT3518 an extremely versatile and
powerful LED driving IC.
The LT3518 has a 45V switch with 2.3A peak switch current limit rating. DC1160 has overvoltage protection at
40V if the LEDs are open or not properly attached to the
terminals on the PCB. The shutdown function is activated
by pulling the shutdown terminal to ground. In shutdown
the boost configuration allows the input voltage to be seen
on the output and if the attached LED array leaks current
at the input voltage, the LEDs may not completely turn off.
If the top gate is installed, it will provide shutdown output
disconnect and the LEDs will turn off during shutdown.
The CTRL terminal can be used to analog dim the LED
current. In order to use the CTRL terminal, R6 (0Ω) pullup short resistor must be removed and replaced with a
resistor divider from VREF to GND or an external voltage
on the CTRL terminal.
The high side PMOS PWM dimming MOSFET can be
used to achieve 3000:1 PWM dimming ratio. The board
is programmed for 1MHz oscillator frequency, but can
be adjusted by changing R14. Higher frequency results
in higher PWM dimming ratio.
The VIN pin can be tied directly to PVIN for simplicity or
powered from an additional low voltage input such as
3.3V for higher efficiency operation and lower on-chip
power dissipation.
A few simple modifications can be made to DC1160 in
order to convert the board from a boost LED driver to a
buck mode or buck-boost mode LED driver. Please consult
the data sheet for schematic details and the factory for
customization details.
The LT3518 data sheet gives a complete description of the
part, operation and applications information. The data sheet
must be read in conjunction with this Quick Start Guide for
demonstration circuit 1160. The LT3518 is assembled in a
small 16-lead plastic (4mm × 4mm) QFN UF package with
a thermally enhanced ground pad. Proper board layout is
essential for maximum thermal performance. See the data
sheet section Layout Considerations.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
dc1160f
1
DEMO MANUAL DC1160
QUICK START PROCEDURE
DC1160 is easy to set up to evaluate the performance of
the LT3518. Follow the procedure below:
5. Turn PVIN power on.
Note: Make sure that the PVIN input voltage does not exceed
40V and that the VIN input voltage does not exceed 30V.
6. Turn VIN power on and observe the regulated LED current, the circuit efficiency, etc. without looking directly
at the LEDs.
1. Connect a string of LEDs with forward voltage less than
40V, but greater than the PVIN input voltage, to the LED+
and GND terminals on the PCB as shown.
7. For PWM dimming, tie a 100Hz, 3V to 5V PWM waveform
to the PWM terminal and GND and observe the PWM
dimming LED current and PWM gate waveforms.
2. With power off, connect a 3.3V input power supply to
the VIN and GND terminals on the PCB.
8. For shutdown, tie the SHDN terminal to GND and
observe the LED current dropping to zero and the VIN
input current dropping to about 65mA with R4 installed
(VIN/51k).
3. With power off, connect a 3V to 40V input power supply
to PVIN and GND terminals on the PCB. PVIN should
not exceed the attached LED string voltage.
PWM
5V/DIV
4. Connect a 3.3V source to PWM and GND.
ILED
200mA/DIV
100
90
IL1
1A/DIV
EFFICIENCY (%)
80
70
1μs/DIV
60
DC1160 F02
Figure 2. 3000:1 PWM Dimming at 100Hz,
PVIN = 12V, VLED = 30V
50
40
30
20
VIN = 12V
CTRL = VREF
0
20
60
80
40
PWM DUTY CYCLE (%)
100
DC1160 F01
Figure 1. DC1160A Efficiency 30V LED String, PVIN = VIN = 12V
dc1160f
2
DEMO MANUAL DC1160
QUICK START PROCEDURE
V
330mA LED ARRAY
+
VLED
–
–
6.5V TO 30V
IPVIN
+
+
A ILED
–
PVIN
+
V
+
A
–
–
IVIN mA
+
+
3.3V
+
VIN
3.3V OR
PWM
V
–
DC1160 F03
OPTIONAL
Figure 3. Proper Measurement Equipment Setup
dc1160f
3
DEMO MANUAL DC1160
PARTS LIST
ITEM
QUANTITY
REFERENCE
PART DESCRIPTION
MANUFACTURER, PART NUMBER
REQUIRED CIRCUIT COMPONENTS:
1
1
C5
Capacitor, X7R, 4.7nF, 25V, 20% 0402
AVX, 04023C472MAT2A
2
2
C3,C4
Capacitor, X7R, 0.01μF, 16V, 10% 0402
AVX, 0402YC103KAT
3
1
CVIN
Capacitor, X7R, 1μF, 50V, 10% 1206
Murata, GRM31MR71H105KA88L
4
2
CPVIN, COUT
5
1
D1
6
1
7
1
8
1
Capacitor, X5R, 2.2μF, 50V, 10% 1206
Murata, GRM31CR71H225KA88L
Schottky Rectifier, 2.1A\60V, SMA
Vishay, 10MQ060NPBF
L1
Inductor, 10μH
Sumida, CDRH8D28-100NC
R1
Resistor, Chip, 0.300Ω, 1/4W, 1% 1206
Vishay, CRCW1206R300FNTA
R8
Resistor, Chip, 392k, 1/16W, 1% 0402
Vishay, CRCW0402392KFKED
9
1
R12
Resistor, Chip, 10k, 1/16W, 1% 0402
Vishay, CRCW040210K0FKED
10
1
R13
Resistor, Chip, 5.1k, 1/16W, 1% 0402
Vishay, CRCW04025K10FKEA
11
1
R14
Resistor, Chip, 16.5k, 1/16W, 1% 0402
Vishay, CRCW040216K5FKEA
12
1
U1
I.C., LT3518EUF
Linear Tech., LT3518EUF#PBF
ADDITIONAL DEMO BOARD CIRCUIT COMPONENTS:
1
0
C1,C2,C6
2
1
Q1
3
2
R6, R7
4
1
5
0
1
12
R4
OPT
MOSFET, P-Channel 40-V (D-S) SOT23
Vishay, Si2319DS-T1-E3
Resistor, Chip, 0, 0402
Vishay, CRCW04020000Z0ED
Resistor, Chip, 51k, 1/16W, 5% 0402
AAC, CR05-513JM
R2, R3, R5,
OPT
R9-R11, R15, R16
HARDWARE FOR DEMO BOARD ONLY:
E1 to E12
Testpoint, Turret, 0.094"
Mill-Max, 2501-2
dc1160f
4
1
2
3
GND
CTRL
PWM
SHDN
GND
A
E10
E7
E8
E6
E5
VIN
E3
3V-30V
40V Transients
R10
Opt.
R4
51k
Opt.
R16
1206
Opt.
R6
0
R2
Opt.
1206
R5
Opt.
OUT
VIN
B
VREF
CTRL
TGEN
C4
0.01uF
5
10
13
PWM
SHDN
U1
LT3518EUF
2
C5
4.7nF
R13
5.1k
R14
16.5k
1%
1MHz
FB
TG
C
Linear Technology Has Made A Best Effort To Design A
Circuit That Meets Customer-Supplied Specifications;
However, It Remains The Customer's Responsibility To
Verify Proper And Reliable Operation In The Actual
Application. Component Substitution And Printed
Circuit Board Layout May Significantly Affect Circuit
Performance Or Reliability. Contact Linear Technology
Applications Engineering For Assistance.
This Circuit Is Proprietary To Linear Technology And
Supplied For Use With Linear Technology Parts.
Customer Notice
LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY
R7
0
C3
0.01uF
R11
Opt.
9
4
CVIN
1uF
50V
10uH
SS
8
4
CPVIN
2.2uF
50V
GND
17
+C2
11
E4
R12
10k
R8
392k
OUT
R1
0.300
1%
1206
E11
E9
E12
1
LED+
330mA
OUT
GND
SYNC
GND
Q2
Opt.
R9
Opt.
OUT
R3
Opt.
PVIN
E2
Opt.
+C1 E1
R15
Opt.
LED+
LED+
PVIN
Q1
Si2319DS
2
3
C6
2.2uF
Opt.
OUT
E
LINEAR TECHNOLOGY CORPORATION
12
16
COUT
2.2uF
50V
D
D
Wednesday, July 18, 2007
Demo Circuit 1160A
Document Number
Sheet
1
E
of
LT3518EUF
1
Rev
Full-Featured LED Driver with 2.3A Switch Current
Date:
Size
A
1630 McCARTHY BLVD.
MILPITAS, CA. 95035
PHONE (408) 432-1900 FAX (408) 434-0507
Title
1
D1
10MQ060N
VC
PVIN
3V-40V
L1
6
CIN Boost
3
VIN
1
SW
2
SW
15
ISP
RT
PVIN
C
ISN
B
1
14
SYNC
7
2
3
A
1
2
3
4
DEMO MANUAL DC1160
SCHEMATIC DIAGRAM
dc1160f
5
DEMO MANUAL DC1160
ASSEMBLY DRAWINGS
Silkscreen Top
dc1160f
6
DEMO MANUAL DC1160
PCB LAYOUT AND FILM
Silkscreen Top
Component Side
dc1160f
7
DEMO MANUAL DC1160
PCB LAYOUT AND FILM
Inner Layer 2
Inner Layer 3
dc1160f
8
DEMO MANUAL DC1160
PCB LAYOUT AND FILM
Soldermask Top
Pastemask Top
dc1160f
9
DEMO MANUAL DC1160
PCB LAYOUT AND FILM
Soldermask Bottom
Pastemask Bottom
Solder Side
dc1160f
10
DEMO MANUAL DC1160
FABRICATION DRAWING
.
.
.
dc1160f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation
that the interconnection of its circuits as described herein will not infringe on existing patent rights.
11
DEMO MANUAL DC1160
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other Intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
dc1160f
12 Linear Technology Corporation
LT 0909 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2009
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