DC2013A - Demo Manual

DEMO MANUAL DC2013A
LT3952EFE
60V LED Driver
with Internal 4A Switch
DESCRIPTION
Demonstration Circuit DC2013A is a 60V LED driver with
internal 4A switch featuring the LT®3952 monolithic LED
driver. It accepts an input voltage from 5V to 36V (with
transient to 42V) and boosts to a single string of LEDs up
to 50V LEDs at 330mA. DC2013A features an integrated
4A switch, constant-current and constant-voltage output
control as well as input current limit and monitoring.
The LT3952 has a wide input voltage range down to 3V
and up to 42V. It has adjustable switching frequency
between 200kHz and 3MHz. It has an option for external
frequency synchronization or spread spectrum frequency
modulation. It has high PWM dimming capability from an
external signal and can be PWM dimmed with an internally
generated PWM oscillator and analog input signal. It can
be analog dimmed with a control voltage on its control
pin. LT3952 features both Open-LED and Short-LED (LED+
to GND) protection as well as fault output flags for each.
Although DC2013A is assembled as a boost LED driver,
it can be altered to be run as a buck mode, buck-boost
mode or boost-buck LED driver.
There is another demonstration circuit featuring LT3952
at 2.0MHz (DC2361A).
DC2013A features an option to turn on spread spectrum
by simply changing the position of a jumper from NO
SPREAD to SPREAD or to EXTERNAL SYNC.
Small ceramic input and output capacitors are used to save
space and cost. The Open-LED overvoltage protection uses
the IC’s constant-voltage regulation loop to regulate the
output to approximately 55V if the LED string is opened
although it may reach 59V peak during transient from
running LEDs to open. There is a protection diode from
LED+ to GND to prevent negative ringing during a shortcircuit with long wires.
There is undervoltage and overvoltage lockout that can be
adjusted on the circuit with a few simple resistor choices.
There is an EMI filter on the input of DC2013A. This EMI
filter has both an LC stage to reduce EMI below 20MHz
and a ferrite bead to reduce higher frequency EMI. The
PCB layout contains a small hot-loop for minimized high
frequency EMI. The EMI filter can be used by connecting
to the “EMI VIN” terminal. However, if the EMI filter is not
needed, the input connection can be directly to the PVIN
terminal. If the EMI filter is not used, it is recommended
to remove the EMI filter if EMI measurements are being
made from the PVIN terminal for base EMI testing. It can
be replaced for EMI testing at the EMI VIN terminal.
The LT3952 data sheet gives a complete description of
the part, operation and applications information. The data
sheet must be read in conjunction with this Demo Manual
for Demonstration Circuit 2013A. The LT3952EFE is assembled in a 28-lead plastic TSSOP (FE) 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/DC2013A
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.
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DEMO MANUAL DC2013A
PERFORMANCE SUMMARY
PARAMETER
CONDITION
Input Voltage PVIN and EMI VIN Range
Operating VIN = PVIN VLED > 36V
MIN
TYP
Switching Frequency
R1 = 287k
350
kHz
5
MAX
36
UNITS
V
ILED
R1 = 0.75Ω 7.0V < PVIN < 36V VLED > 36V
333
mA
Low PVIN ILED (CTRL Foldback)
R1 = 0.75Ω PVIN = 5.0V
R1 = 0.75Ω PVIN = 6.0V
270
320
mA
mA
VLED Range
R4 = 1M, R5 = 22.6k
Open-LED Voltage VOUT
R4 = 1M, R5 = 22.6k
54.3
V
PVIN
50
V
Typical Efficiency (100% PWM DC)
PVIN = 14V VLED = 50V ILED = 333mA
92.2
%
Input Undervoltage Lockout (Falling Turn-Off)
R7 = 499k, R8 = 196k, R9 = 24.3k
4.1
V
Input Undervoltage Lockout (Rising Turn-On)
R7 = 499k, R8 = 196k, R9 = 24.3k
5.4
V
VISMON
Operating ILED = 330mA
1.0
V
Peak Switch Current Limit
Operating
4
A
QUICK START PROCEDURE
Demonstration Circuit 2013A is easy to set up to evaluate the
performance of the LT3952. Follow the procedure below:
1.Connect a string of LEDs that will run with forward voltage less than or equal to 50V (at 330mA), but greater
than PVIN, to the LED+ and GND terminals on the PCB
as shown in Figure 1.
2.Connect the EN/UVLO terminal to GND.
3.With power off, connect the input power supply to the
EMI VIN (or PVIN) and GND terminals. Make sure that
the DC input voltage will not exceed 42V (or VLED).
4.Turn the input power supply on and make sure the voltage
is between 5V and 36V (or VLED) for proper operation.
5.Release the EN/UVLO-to-GND connection.
6.Observe the LED strings running at the programmed
LED current.
7.To change the brightness with analog dimming, simply
attach a voltage source to the CTRL terminal and set the
voltage between 0V and 1.5V. See data sheet for details.
8.To change brightness with external PWM dimming,
attach a 3V rectangular waveform with varying duty
cycle to the PWM terminal.
9.To enable spread spectrum frequency modulation,
simply change the position of the shunt on the SYNC/
SPRD jumper to the SPREAD SPECTRUM position.
2
DEMO CIRCUIT OPTIONS
Demonstration Circuit 2013A can be adjusted for higher
or lower output voltage, different LED current, or different
topology. The following options are for simple changes
to the demonstration circuit. The data sheet gives more
information regarding designing with the LT3952. For
more information, see the data sheet for details or contact
Linear Tech customer support.
MAXIMUM LED VOLTAGE
DC2013A is set for 54.3V of overvoltage protection and
the maximum LED string voltage used on the standard
build should be 50V. Some margin is provided to limit
the Open-LED overshoot above 55V in order to stay safely
below the 60V limit. See data sheet for details.
CURRENT OR VOLTAGE REGULATION
The LT3952 can be used for constant-current or voltage
regulation. If the load placed on the LED+ to GND terminals
allows VOUT to climb high enough for V(ISP-ISN) = 1.2V, then
the voltage regulation loop of the converter takes over. In
this case, the compensation for a given channel should be
adjusted for proper use as a constant-voltage regulator.
The IC can be used as a boost or SEPIC constant-voltage
regulator. Output voltage should remain below 60V when
used as a constant-voltage device.
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DEMO MANUAL DC2013A
QUICK START PROCEDURE
LED CURRENT
LED current on DC2013A is set for 330mA with 0.75Ω
resistor R1. For a different maximum LED current, change
this resistor. 250mV/RLED = ILED.
boost-buck see data sheet for details how to set the feedback
resistors. Note that R19, R20, R21, and Q1 are provided as
optional placeholders on the demonstration circuit for simple
feedback resistor changes for these topologies.
A change in LED current or input voltage may lead to higher
or lower maximum switch current. The maximum switch
current for this converter is 4A and is fixed internally.
UNDERVOLTAGE AND OVERVOLTAGE LOCKOUT
OVERVOLTAGE PROTECTION
Resistors R13, R14, and R15 are available for setting
UVLO and OVLO separately or for referring them to OUT
for other topologies.
Overvoltage protection is set with the resistor pair R4 and R5
for the boost topology. For buck mode, buck-boost mode, and
UVLO and OVLO can be adjusted by changing the values
of R7, R8 and R9.
Figure 1. Test Procedure Setup Drawing for DC2013A
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DEMO MANUAL DC2013A
QUICK START PROCEDURE
Figure 2. DC2013A 12VIN 120Hz PWM Dimming Waveforms at Different PWM Duty Cycles with 1500:1 in Bold.
ILED Waveform (200mA/DIV) Is on Top (with 50V LED String) and IL1 Waveform (1A/DIV) Is on the Bottom
0.35
0.30
ILED(A)
0.25
0.20
0.15
0.10
0.05
0
0
1
2
3
4
5
6 7
PVIN(V)
8
9
10 11 12 31 32 33 34 35 36 37 38 39 40
DC2013A F03
PVIN(V)
Figure 3. DC2013A CTRL LED Current Foldback at Low Input with UVLO and OVLO Falling and Rising
4
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DEMO MANUAL DC2013A
QUICK START PROCEDURE
100
EFFICIENCY (%)
95
90
85
80
75
70
0
5
10
15
20 25
PVIN (V)
30
35
40
DC2013A F04
Figure 4. DC2013A Efficiency at Maximum ILED vs PVIN with 50V LEDs (at 330mA)
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART #
Required Electrical Components
1
1
C1
CAP., X5R, 10μF, 50V, 10% 1206
MURATA, GRM31CR61H106KA12L
2
1
C2
CAP., X7S, 4.7μF, 100V, 10% 1206
AVX, 12061Z475KAT2A
3
1
C3
CAP., X7R, 0.22μF, 10V, 10% 0603
MURATA, GRM188R71A224KA01J
4
1
C4
CAP., X7R, 4.7nF, 10V, 10% 0603
AVX, 0603ZC472KAT2A
5
1
C5
CAP., X5R, 2.2µF, 6.3V, 10% 0603
AVX, 06036D225KAT2A
6
1
C6
CAP., X7R, 1μF, 50V, 10% 0805
MURATA, GRM21BR71H105KA12L
7
1
D1
SCHOTTKY RECTIFIER
DIODES INC., DFLS260-7
8
1
L1
INDUCTOR, 15μH
WÜRTH ELEKTRONIK, 7447798151
9
1
M1
P-MOSFET, SI2307CDS, SOT23
VISHAY, SI2307CDS-T1-GE3
10
1
R1
RES., CHIP, 0.75Ω, 0.5W, 1% 1206
SUSUMU, RL1632R-R750-F
11
1
R2
RES., CHIP, 287k, 1/10W, 1% 0603
VISHAY, CRCW0603287KFKEA
12
1
R3
RES., CHIP, 3.0k, 1/10W, 5% 0603
VISHAY, CRCW06033K00JNEA
13
1
R4
RES., CHIP, 1M, 1/10W, 1% 0603
VISHAY, CRCW06031M00FKEA
14
1
R5
RES., CHIP, 22.6k, 1/10W, 1% 0603
VISHAY, CRCW060322K6FKEA
15
1
R6
RES., CHIP, 0.015Ω, 1W, 1% 1206
PANASONIC, ERJ-8BWFR015V
16
1
U1
I.C., LED Driver, TSSOP-28
LINEAR TECH., LT3952EFE#PBF
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DEMO MANUAL DC2013A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART #
Optional Electrical Components
1
1
C7
CAP., X7R, 0.47μF, 25V, 10% 0603
MURATA, GRM188R71E474KA12D
2
1
C8
CAP., ALUM., 33µF, 50V, 6.3 × 7.7
PANASONIC, EEHZA1H330XP
3
1
C9
CAP., X5R, 2.2µF, 50V, 10% 1206
MURATA, GRM31CR71H225KA88L
4
1
C10
CAP., X5R, 0.1µF, 50V, 10% 0402
MURATA, GRM155R61H104KE14J
5
0
C11, C12, C17 (OPT)
CAP., 0603
6
0
C13, C14 (OPT)
CAP., 1206
7
0
C15, C16 (OPT)
CAP., 1206
8
0
C18 (OPT)
CAP., 0805
MURATA, GRM21BR71H105KA12L
9
1
D2
RECTIFIER, SMA
DIODES INC., ES1B-13-F
10
1
FB1
BEAD, CHIP, 100Ω, 0805
TDK, MPZ2012S101AT000
11
1
L2
INDUCTOR, 4.7µH
VISHAY, IHLP2020CZER4R7M11
12
0
Q1 (OPT)
PNP SOT23
13
1
R7
RES., CHIP, 499k, 1/10W, 1% 0603
VISHAY, CRCW0603499KFKEA
14
1
R8
RES., CHIP, 196k, 1/10W, 1% 0603
VISHAY, CRCW0603196KFKEA
VISHAY, CRCW060324K3FKEA
15
1
R9
RES., CHIP, 24.3k, 1/10W, 1% 0603
16
0
R10 (OPT)
RES., 0402
17
2
R11, R12
RES., CHIP, 100k, 1/10W, 1% 0603
18
0
R13-R15, R18-R21,
R24-R26 (OPT)
RES., 0603
19
1
R16
RES., CHIP, 1M, 1/10W, 1% 0603
VISHAY, CRCW06031M00FKEA
20
1
R17
RES., CHIP, 249k, 1/10W, 1% 0603
VISHAY, CRCW0603249KFKEA
21
0
R22, R23 (OPT)
RES., 0805
1
8
E1-E8
TESTPOINT, TURRET, 0.094" PBF
2
11
E9-E19
TESTPOINT, TURRET, 0.061" PBF
MILL-MAX, 2308-2-00-80-00-00-07-0
3
1
JP1
HEADER 3-PIN 0.079" DOUBLE ROW
WÜRTH ELEKTRONIK, 620 006 211 21
4
1
XJP1
SHUNT, 0.079" CENTER
WÜRTH ELEKTRONIK, 608 002 134 21
VISHAY, CRCW0603100KFKEA
Hardware
6
MILL-MAX, 2501-2-00-80-00-00-07-0
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DEMO MANUAL DC2013A
SCHEMATIC DIAGRAM
dc2013af
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.
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DEMO MANUAL DC2013A
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
8
dc2013af
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●
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