DC1497A - Demo Manual

DEMO MANUAL DC1497A
LT3597
60V Triple Step-Down
LED Driver
Description
Demonstration circuit 1497A is a 60V triple step-down LED
driver featuring the LT3597. The demo board is optimized
for 9 white LEDs, 100mA output per regulator from a 48V
input. When different number or different color of LEDs
is used for evaluation, attentions should be given to the
maximum output voltage setting and fault reporting. The
connections between the board and LEDs strings should
be as short as feasible.
The circuit achieves 10,000:1 PWM dimming at 100Hz
PWM frequency. LED dimming can also be done by analog
control of the CTRL1-3 pin. If dimming is not required,
leave the PWM1-3 and CTRL1-3 terminals unconnected.
The demo circuit pulls PWM1-3 and CTRL1-3 pins up
to VREF. The switching frequency is set to 1MHz on the
demo circuit for best solution size. The LT3597 internal
compensation makes it a lot easier for a designer to design
different application circuits.
The LT3597 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 1497A.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, µModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
PWM
2V/DIV
ILED
50mA/DIV
200ns/DIV
DC1497a
Figure 1. PWM Dimming
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DEMO MANUAL DC1497A
PERFORMANCE SUMMARY
(TA = 25°C)
SYMBOL
PARAMETER
CONDITIONS
MIN
VIN*
Input Supply
6
VLED
LED String Voltage
28
VOUT(MAX)
Maximum Output Voltage
IOUT
Output Current
R23 = R24 = R25 = 20k
DIM
PWM Dimming Ratio
PWM Dimming Frquency = 100Hz
FSW
Switching Frequency
R22 = 33.2k
EFE
Efficiency
VIN = 48V, VOUT = 29V, IOUT = 100mA, BIAS = 5V, No Dimming
TYP
MAX
55
34
38
98
100
UNITS
V
V
V
102
mA
1.1
MHz
10,000:1
0.9
1
87
%
*Actual VIN range should be determined by the load. For 9 white LEDs per channel, use a 48V input for evaluation.
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DEMO MANUAL DC1497A
quick start procedure
Demonstration circuit 1497A is easy to set up to evaluate the performance of the LT3597. Refer to Figure 2 for
proper measurement equipment setup and follow the
procedure below:
1.With power off, connect the input power supply to VIN
and GND.
2.With power off, connect a 5V bias supply to BIAS and
GND. Bias voltage should be less then 25V.
3. With power off, connect 3 LED strings, 9 white LEDs per
string, between LED1+ and LED1–, LED2+ and LED2–,
LED3+ and LED3– respectively.
4.Turn on the power at the input. Be careful not to look
at the LEDs directly.
5.Carefully evaluate all design parameters as needed.
6.To evaluate PWM dimming, apply a PWM signal to
PWM1, PWM2 and/or PWM3. To evaluate 10,000:1 PWM
dimming, the PWM signal should have a frequency of
100Hz and the minimum pulse width can be as low as
1µs.
7. To modify the demo board for other applications, please
contact the Linear Applications Group for help.
Figure 2. Demo Board Setup
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DEMO MANUAL DC1497A
parts list
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
3
C1, C2, C3
Capacitor, X7R, 4.7µF, 50V, 10%,1206
Murata, GRM31CR71H475KA12L
2
3
C4, C5, C6
Capacitor, X7R, 0.22µF, 25V, 10%, 0603
Murata, GRM188R71E224KA88L
3
2
C7, C10
Capacitor, X7R, 2.2µF, 100V, 10%, 1210
Murata, GRM32ER72A225KA35L
4
1
C8
Capacitor, X5R, 4.7µF, 25V, 10%, 0805
Taiyo Yuden, TMK212BJ475KG-T
5
3
D1, D2, D3
Diode, Schottky, Power DI-123
Diodes/Zetex, DFLS160-7
6
3
L1, L2, L3
Inductor, 100µH
Sumida, CDR6D28MNNP-101NC
7
3
R1, R2, R3
Resistor, Chip, 93.1k, 1/16W, 1%, 0402
Vishay, CRCW040293K1FKED
8
3
R4, R5, R6
Resistor, Chip, 3.01kΩ, 1/16W, 1%, 0402
Vishay, CRCW04023K01FKED
9
1
R16
Resistor, Chip, 82.5kΩ, 1/16W, 1%, 0402
Vishay, CRCW040282K5FKED
10
1
R19
Resistor, Chip, 49.9kΩ, 1/16W, 1%, 0402
Vishay, CRCW040249K9FKED
11
1
R20
Resistor, Chip,10kΩ, 1/16W, 1%, 0402
Vishay, CRCW040210K0FKED
12
1
R22
Resistor, Chip, 33.2kΩ, 1/16W,1%, 0402
Vishay, CRCW040233K2FKED
13
3
R23, R24, R25
Resistor, Chip, 20kΩ, 1/16W, 1%, 0402
Vishay, CRCW040220K0FKED
14
1
U1
I.C. LT3597EUHG, 52-Pin QFN-5mm × 8mm
Linear Technology, LT3597EUHG
Capacitor, Aluminum 4.7µF, 63V
Sun Electric, 63CE4R7BS
Additional Demo Board Circuit Components
1
1
C9
2
0
D4
Diode, OPT, SOD-323
3
1
R7
Resistor, Chip, 270kΩ, 1/16W, 1%, 0603
Vishay, CRCW0603270KFKEA
4
1
R9
Resistor, Chip, 91kΩ, 1/16W, 1%, 0402
Vishay, CRCW040291K0FKED
5
7
R10-R14, R17, R18
Resistor, Chip, 100kΩ,1/16W,1%, 0402
Vishay, CRCW0402100KFKED
6
1
R15
Resistor, Chip, 8.87kΩ,1/16W, 1%, 0402
Vishay, CRCW04028K87FKED
7
1
R21
Thermistor, Chip, 100k,1%, 0603
Murata, NCP18WF104F12RB
Turret, Testpoint, 091"
Mill Max 2501-2-00-80-00-00-07-0
Hardware – For Demo Board Only
1
8
E1-E5, E12-E14
2
10
E6-E11, E15-E18
Turret, Testpoint, 063"
Mill Max 2308-2-00-80-00-00-07-0
3
1
JP1
Jumper, 3-Pin 1 Row .079CC
Samtec, TMM-103-02-L-S
4
1
SHUNT FOR PJ1
Shunt, .079" Center
Samtec, 2SN-BK-G
5
4
Stand-Off, Nylon 0.5" Tall
Keystone, 8833 (Snap On)
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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.
A
B
C
D
FAULT
BIAS
TP
SYNC
CTRL3
CTRL2
CTRL1
PWM3
PWM2
PWM1
GND
VIN
6V - 55V
E15
E17
E19
5
+
R20
10K
E18
E11
E10
E9
E8
E7
E6
E5
E4
OPT
D4
R22
33.2K
C9
4.7uF
63V
R24
20K
R25
20K
R17
100K
R14
100K
C10
2.2uF
100V
1210
53
16
15
14
17
27
31
32
33
26
GND
ISET3
ISET2
ISET1
RT
SYNC
CTRL3
CTRL2
CTRL1
NC
R13 R12
100K 100K
R10
100K
C8
4.7uF
25V
0805
4
1. ALL RESISTORS ARE 0402
NOTE: UNLESS OTHERWISE SPECIFIED
R23
20K
R18
100K
VREF
C7
2.2uF
100V
1210
R11
100K
VREF
30
VIN
4
29
PWM2
28
PWM3
GND
18
BIAS
37
FAULT
25
R7
270K
0603
R19
49.9K
R16
82.5K
LED3
VOUT3
FB3
DA3
SW3
BST3
LED2
VOUT2
FB2
DA2
SW2
BST2
LED1
2
24
23
35
43
41
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
2
WALKER B.
AK
APPROVALS
1
DATE:
SIZE
R6
3.01K
50V
C3
C2
50V
R5
3.01K
DESCRIPTION
E14
E3
E13
E2
LED3-
LED3+
LED2-
LED2+
LED1-
LED1+
OFF
ON
EN/UVLO
Wednesday, February 02, 2011
1
DEMO CIRCUIT 1497A
LT3597EUHG
SHEET
TRIPLE STEP-DOWN LED DRIVER
IC NO.
DATE
01-26-11
1
OF 1
2
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
R3
93.1K
4.7uF
1206
E1
JP1
3
2
1
E12
LED2+
APPROVED
WALKER B.
EN/UVLO
E16
LED1+
LED3+
R2
93.1K
4.7uF
1206
R1
93.1K
4.7uF
1206
TECHNOLOGY
L3
100uH
C1
50V
1
REVISION HISTORY
2ND PROTOTYPE
R4
3.01K
L2
100uH
L1
100uH
1
REV
TITLE: SCHEMATIC
D3
DFLS160
2
C6
0.22uF
0603
D2
DFLS160
39
1
C5
0.22uF
0603
1
__
ECO
D1
DFLS160
2
C4
0.22uF
0603
2
2
21
22
34
44
46
48
20
19
7
6
4
CUSTOMER NOTICE
t
FB1
DA1
SW1
BST1
R9
91K
VOUT1
3
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
R15
8.87K
R21
100K
0603
VREF
U1
LT3597EUHG
PWM1
TSET
11
51
VIN
50
VIN
VREF
12
9
EN/UVLO
CTRLM
13
5
A
B
C
D
DEMO MANUAL DC1497A
Schematic Diagram
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DEMO MANUAL DC1497A
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
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Linear Technology Corporation
LT 0411 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2011
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