DC1734A - Demo Manual

DEMO MANUAL DC1734A
LT8582
Dual 3A Boost/Inverting/SEPIC
DC/DC Converter
DESCRIPTION
Demonstration circuit 1734A features the dual channel
LT®8582 in boost and inverting regulator configurations.
The circuit is designed to convert a 5V to 10V input source
to 12V at 900mA and –12V at 590mA as shown in Table 1.
Table 1. Maximum Guaranteed Output Currents
VIN (V)
MAX ILOAD1 (mA)
MAX ILOAD2 (mA)
4.5
775
540
5.0
900
590
5.5
1000
625
To limit the temperature rise of the chip to 40°C, on the
demo board with no air flow, the maximum combined
output power is 15W. Additional input bulk capacitance
may be needed, subject to source impedance.
DC1734A is designed to survive output short circuit events.
On the positive channel an external disconnect MOSFET
protects the boost converter. The negative channel is
based on dual inductor inverting topology and does not
need the external MOSFET as it is inherently output short
protected. The circuit board includes an option to install
the external disconnect MOSFET at the input side of the
positive channel. To use it, remove Q1 and R1 from the
top of the circuit board and install them on the back, in
the location of Q2 and R2. Then, place a jumper from Q1’s
source to drain and cut the top copper as shown in Figure 6.
PERFORMANCE SUMMARY
SYMBOL
PARAMETER
VIN
Input Supply Range
VOUT1
VOUT2
fS
To change the topology of channel 1 from boost to inverting: Replace D1 with a capacitor similar to C12, replace
C2 with a diode similar to D3, placing the diode so that
its cathode is connected to ground, and replace R16 with
an inductor similar to L3.
To change the topology of channel 2 from inverting to boost:
Replace C12 with a diode similar to D1, placing the diode so
that its anode is connected to L2, replace D3 with a capacitor
similar to C2, and replace L3 with a jumper resistor similar
to R16. However, this configuration will not be output short
protected since it lacks the external disconnect MOSFET.
Each channel of the LT8582 includes a 42V master and slave
power switch combination with 3A total current and can easily
be configured as a boost, SEPIC, inverting or flyback converter.
The LT8582 has a 2.5V to 22V operating input range, UVLO,
soft-start, programmable switching frequency and many other
features. The LT8582 data sheet gives a complete description
of the part, its operation and application information. The
data sheet must be read in conjunction with this quick start
guide for working on or modifying the demo circuit 1734A.
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.
(TA = 25°C)
CONDITIONS
MIN
TYP
MAX
Channel 1 Output Voltage Accuracy
VIN = 5V to 10V, ILOAD = 900mA
11.6
10
V
12
12.4
V
Channel 1 Output Voltage Ripple
VIN = 5V, ILOAD = 900mA
60
Channel 1 Efficiency
VIN = 5V, ILOAD = 900mA
86
%
Channel 1 Efficiency
VIN = 10V, ILOAD = 900mA
92
%
Channel 2 Output Voltage Accuracy
VIN = 5V to 10V, ILOAD = 590mA
5
–11.5
–12
UNITS
mVPP
–12.3
V
Channel 2 Output Voltage Ripple
VIN = 5V, ILOAD = 590mA
56
mVPP
Channel 2 Efficiency
VIN = 5V, ILOAD = 590mA
83
%
Channel 2 Efficiency
VIN = 10V, ILOAD = 590mA
85
%
1
MHz
Switching Frequency
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DEMO MANUAL DC1734A
QUICK START PROCEDURE
Demonstration circuit DC1734A is easy to set up to evaluate the performance of the LT8582. Refer to Figure 1 for
proper measurement equipment set-up and follow the
procedure below.
1. Place the on board jumpers in the following positions:
To measure voltage ripple, care must be taken to avoid a
long ground lead on the oscilloscope probe. Remove the
oscilloscope probe end cap and ground lead and set the
bandwidth limit on the oscilloscope. Measure the input
voltage ripple by touching the probe tip and ground directly
across VIN and GND terminals. See Figure 2 for proper
input voltage ripple measurement technique. Measure the
positive output voltage ripple by touching the probe tip
directly across output capacitor C16 terminals, connecting the probe ground terminal to the board’s GND plane.
Measure the negative output voltage ripple by touching the
probe tip directly across output capacitor C9, connecting
the probe ground terminal to the board’s GND plane. See
Figure 3 for proper output voltage ripple measurement
technique.
2. With power off, connect the input power supply to VIN
and GND. Apply 7.5V to the input (source must have
greater than 10A capability).
To activate boost converter: JP1 ON
To activate inverting converter: JP2 ON
3. Check for the proper output voltages.
NOTE. If there is no output, temporarily disconnect the
load to make sure that the load is not set too high.
4. Once the proper output voltage is established, adjust
the load and the input voltage within the operating
range and observe the output voltage regulation, ripple
voltage, efficiency and other parameters. The efficiency
graphs of the two channels are provided in Figure 4
and Figure 5.
Figure 1. Proper Measurement Equipment Setup
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DEMO MANUAL DC1734A
QUICK START PROCEDURE
OSCILLOSCOPE
PROBE
VIN
GND
Figure 2. Proper Input Voltage Ripple Measurement Technique
OSCILLOSCOPE
PROBE
SOLDER A SMALL
PIECE OF SOLID WIRE
SOLDER
OUTPUT
CAP.
BOARD GND
PLANE
Figure 3. Proper Output Voltage Ripple Measurement Technique
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DEMO MANUAL DC1734A
QUICK START PROCEDURE
100
90
EFFICIENCY (%)
80
70
60
50
40
30
20
10
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
LOAD CURRENT (A)
dc1734a F04
Figure 4. Channel 1 Boost Regulator Efficiency at VIN = 5V
100
90
EFFICIENCY (%)
80
70
60
50
40
30
20
10
0
0
0.1
0.2
0.3
0.4
LOAD CURRENT (A)
0.5
0.6
dc1734a F05
Figure 5. Channel 2 Inverting Regulator Efficiency at VIN = 5V
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DEMO MANUAL DC1734A
BOARD MODIFICATIONS
SHORT Q1’s SOURCE AND
DRAIN PADS HERE
CUT COPPER
HERE
Figure 6. Using Channel 1 Input Disconnect Option (See Text)
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DEMO MANUAL DC1734A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
3
C1, C2
CAP., X5R, 10μF, 16V, 20% 1206
AVX, 1206YD106MAT2A
2
1
C9, C16
CAP., X5R, 22μF, 16V, 20% 1206
TAIYO YUDEN, EMK316BJ226ML-T
3
2
C11, C17
CAP., X5R, 4.7μF, 16V, 20% 1206
TAIYO YUDEN, EMK316BJ475ML-T
4
2
C4, C8
CAP., X7R, 2.2nF, 50V, 10%, 0402
AVX, 04025C222KAT2A
5
2
C5, C10
CAP., NPO, 100pF, 16V, 10%, 0402
AVX, 0402YA101KAT2A
6
2
C6, C7
CAP., X7R, 0.1μF, 16V, 10% 0402
TDK, C1005X7R1C104K
7
1
C12
CAP., X7R, 2.2μF, 25V, 10%, 0805
MURATA, GRM21BR71E225KA73L
8
1
D1
RECTIFIER, DFLS220L, PowerDI-123
DIODES/ZETEX, DFLS220L-7
9
1
D3
RECTIFIER, DFLS130L, PowerDI-123
DIODES/ZETEX, DFLS130L-7
10
1
L1
INDUCTOR, 4.7μH
VISHAY, IHLP2525CZER4R7M11
11
1
L2
INDUCTOR, 10μH
VISHAY, IHLP2525CZER100M11
12
1
L3
INDUCTOR, 10μH
VISHAY, IHLP2020BZER100M11
13
1
Q1
P-CH MOSFET, FDMC510P, POWER-33
FAIRCHILD, FDMC510P
14
1
R1
RES., CHIP, 6.04k, 1/16W, 1% 0402
VISHAY, CRCW04026K04FKED
15
1
R3
RES., CHIP,130k, 1/10W, 1%, 0603
NIC, NRC06F1303TRF
16
2
R4, R11
RES., CHIP, 232k, 1/8W, 1%, 0805
VISHAY, CRCW0805232KFKEA
17
1
R5
RES., CHIP, 8.06k, 1/16W, 1% 0402
VISHAY, CRCW04028K06FKED
18
2
R8, R10
RES., CHIP, 80.6k, 1/16W, 1% 0402
VISHAY, CRCW040280K6FKED
19
3
R6, R9, R13
RES., CHIP, 100k, 1/16W, 5% 0402
NIC, NRC04J104TRF
20
1
R12
RES., CHIP, 16.9k, 1/16W, 1% 0402
VISHAY, CRCW040216K9FKED
21
1
R15
RES., CHIP,143k, 1/10W, 1%, 0603
NIC, NRC06F1433TRF
22
1
R16
RES., CHIP, 0Ω, 1/4W, 1206
NIC, NRC12ZOTR
23
1
U1
IC., LT8582EDKD, DFN-24(7MMX4MM)
LINEAR TECH., LT8582EDKD
Additional Demo Board Circuit Components
1
0
C3, C14
CAP., 0603, OPTION
2
0
C13
CAP., 1206, OPTION
3
0
C15
CAP., SMD 8X10.5 & THRU HOLE 8X9.5, OPTION
4
0
D2
DIODE, SOD-323, OPTION
5
0
Q2
MOSFET, POWER-33, OPTION
6
0
R2
RES., CHIP, 0402, OPTION
7
0
R7, R14
RES., CHIP, 0805, OPTION
Hardware for Demo Board Only
1
9
E1-E9
TESTPOINT, TURRET, .094" pbf
MILL-MAX, 2501-2-00-80-00-00-07-0
2
2
JP1, JP2
3 PIN 0.079 SINGLE ROW HEADER
SAMTEC, TMM103-02-L-S
3
2
XJP1, XJP2
SHUNT, .079" CENTER
SAMTEC, 2SN-BK-G
4
4
(STAND-OFF)
STAND-OFF, NYLON 0.25"
KEYSTONE, 8831(SNAP ON)
5
1
FAB, PRINTED CIRCUIT BOARD
DEMO CIRCUIT 1734A
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DEMO MANUAL DC1734A
SCHEMATIC DIAGRAM
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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.
7
DEMO MANUAL DC1734A
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
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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.
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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 1111 • PRINTED IN USA
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●
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