DC2220A - Demo Manual

DEMO MANUAL DC2220A
LTC3643
Bidirectional Charger/Regulator for
System Power Backup
DESCRIPTION
Demonstration circuit 2220A is a 2A, bidirectional charger/
regulator featuring the LTC®3643, a bidirectional synchronous step-up charger and step-down converter. DC2220A
implements backup by charging a storage capacitor up to
40V in boost mode, when the input voltage is present. It
discharges the storage capacitor in buck mode, providing
a regulated load voltage of 3V to 17V (set to 5V), when
the input is interrupted. Its wide voltage range, both in
capacitor charger mode and in system backup mode,
makes it well suited to a wide variety of applications. The
ability of the LTC3643 to boost an input rail to a relatively
high voltage of 40V, combined with the DC2220 option of
adding external capacitor banks, makes this regulator an
excellent choice for energy storage applications.
The DC2220A features automatic switching from charge
to backup mode, 2A input current limit during charging,
the ability to set maximum current in the backup mode of
operation, Burst Mode® operation, fast 1MHz switching
frequency, and open-collector outputs to indicate charge
status and input power fail.
The 1MHz constant-frequency operation results in a small
and efficient circuit. In backup mode, the LTC3643 provides
high output voltage accuracy over a wide load range with
no minimum load requirement.
Demo circuit 2220A is set up for automatic mode operation. In this mode, the DC2220 automatically charges the
energy storage capacitor when a system voltage is present.
It automatically switches to work as a step-down DC/DC
converter providing system backup power to the load when
system power is removed. An on board MOSFET isolates
the backup circuit from the input line if the system voltage
is not present, implementing PowerPath™ functionality.
The DC2220A supports three levels of load current limits:
2A, 3A and 4A when working as step-down converter
discharging the energy storage capacitor.
The DC2220A has a small circuit footprint. It is a high
performance and cost effective solution for high voltage
capacitor backup converters, servers, solid-state drives,
RAID and RF systems.
The LTC3643's input disconnect circuitry protects the
DC2220A from short circuit and overcurrent conditions
in the boost mode of operation, in case a short circuit occurs on a high voltage rail. A similar circuit protects the
DC2220A against a short circuit in step-down mode, when
the load is supplied from an energy storage capacitor.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2220A
L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks
and PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
PERFORMANCE SUMMARY
Specifications are at TA = 25°C
PARAMETER
CONDITIONS
UNITS
Minimum Input Supply Voltage
3.0
V
Maximum Input Supply Voltage
17.0
V
3.0 to 17.0
V
System Voltage Range
Backup (Step-Down) Mode
Energy Storage Capacitor Voltage Range
3.0V to 40V
Typical Switching Frequency
Efficiency Typical, Backup Mode
VCAP = 12V, VLOAD = 5.0V, ILOAD = 0.5A
V
1.0
MHz
93
%
dc2220afb
1
DEMO MANUAL DC2220A
QUICK START PROCEDURE
Demonstration circuit 2220A is easy to set up to evaluate
the performance of the LTC3643 bidirectional regulator.
Refer to Figure 1 for the proper measurement equipment
setup and follow the procedure below.
NOTE: When measuring the input or output voltage ripple,
care must be taken to avoid a long ground lead on the
oscilloscope probe. Measure the input or output voltage
ripple by touching the probe tip directly across the VIN or
VOUT and GND terminals. See Figure 2 for proper scope
probe technique.
To verify the capability of the DC2220A for charging energy
storage capacitors, proceed with the following steps:
1. Place jumper RUN (JP1) to OFF position.
2. Place jumper ILIM_BUCK (JP2) to 2.0A position.
3. With power off, connect the input power supply to
terminals VIN (E1) and GND, voltmeter to VCAP (E8)
and GND, load to LOAD (E3) and GND as shown on
Figure 1.
–
20V
POWER
SUPPLY
+
–
+
+
–
LOAD
Figure 1. Proper Measurement Equipment Setup
GND
VIN
Figure 2. Measuring Input or Output Ripple
2
dc2220afb
DEMO MANUAL DC2220A
QUICK START PROCEDURE
4. Turn the input power source on and slowly increase
the input voltage to 5.5V. Set the load to 0.1A. You
have to see voltage around 4.8V on terminal LOAD,
a diode forward voltage drop lower compared to VIN.
If there is no output, temporarily disconnect the load
to make sure that the load is not set too high.
5. Place jumper RUN (JP1) in the ON position. Voltage
on VCAP terminal should rise to 39V level. Voltage on
terminal LOAD should be equal to input voltage.
To verify the ability of DC2220 to work in backup mode,
proceed with the following:
6. Disconnect input power from VIN terminal; energy
storage capacitor C5 starts discharging from 39V level,
however LTC3643 will maintain a voltage of 5.0V on
terminal LOAD.
7. To increase holdup time, install optional capacitor C6
on the bottom side of DC2220A or connect additional
capacitor bank to terminals VCAP (E8) and GND (E7).
8. Repeat steps 1 to 7 for different load currents and VIN
voltages.
9. You can measure voltage regulation and ripple in
backup mode on VLOAD terminals.
10.Make sure that input voltage on VIN terminals does not
exceed 17V and VCAP voltage is not set above 40V.
Figure 3 illustrates power interruption. In the beginning of
the process VIN (yellow) is 5.5V and supplies LOAD rail,
PFI signal is low and step-down converter is OFF. Once
VIN value is reduced to 4.75V, PFI signal changes state
to high, the step-down converter turns ON and starts to
supply the LOAD rail by 5.0V taking energy from the storage
capacitor C5. The efficiency curve is presented in Figure 4.
The efficiency measurement was conducted in step-down
mode. A constant DC voltage of 12V was applied to the VCAP
and GND terminals with the input voltage disconnected
from the VIN and GND terminals.
VLOAD
VLOAD
VIN
VIN
1V/DIV
1V/DIV
PFI
PFI
DC2220 F03a
200µs/DIV
50ms/DIV
3a
DC2220 F03b
3b
Figure 3. Power interruption, VLOAD 5.0V, ILOAD 0.5A
96
95
EFFICIENCY (%)
94
93
92
91
90
89
88
87
86
0
0.5
1
1.5
2
LOAD CURRENT (A)
2.5
3
DC2220 F04
Figure 4. Efficiency vs Load, VCAP 12V, LOAD 5.0V, Step-Down Mode
dc2220afb
3
DEMO MANUAL DC2220A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
CAP., X7R, 0.1µF, 25V, 10%, 0603
AVX, 06033C104KAT2A
Required Circuit Components
1
1
C1
2
1
C2
CAP., X5R, 4.7µF,16V, 10%, 0805
TDK C2012X5R1C475K
3
1
C3
CAP., C0G, 470pF 50V, 5%, 0603
AVX, 06035A471JAT2A
4
1
C4
CAP., C0G, 22pF, 25V, 5%, 0603
AVX, 06033A220JAT2A
5
1
C5
CAP., ALUM., ELECT., 1000µF, 50V, 16x16.5
PANASONIC, EEEFK1H102AM
6
2
C9, C11
CAP., POS 47µF, 20V, 20%,TQC-D2
PANASONIC, 20TQC47MYF
7
1
C10
CAP., X7R, 4.7µF, 50V, 10%,1210
AVX, 12105C475KAT2A
8
3
C12, C13, C14
CAP., X7R, 10µF, 50V, 10%, 210
AVX, 12105C106KAT2A
9
1
C15
CAP., X7S, 1µF, 100V, 10%, 0805
TDK C2012X7S2A105K
10
1
L1
IND, 7.2µH POWER
SUMIDA, CDEP105NP-7R2MC-88
11
1
Q1
MOSFET, P-CHN, 30V, LFPAK
VISHAY, Si4491EDY-T1-GE3
12
1
R1
RES., CHIP, 511k, 1/10W, 1%, 0603
VISHAY, CRCW0603511KFKEA
13
1
R2
RES., CHIP, 0.01, 1/4W, 1%, 1206
VISHAY, WSL1206R0100FEA
14
1
R3
RES., CHIP, 133k, 1/16W, 1%, 0603
VISHAY, CRCW0603133KFKEA
15
1
R4
Res., CHIP, 1MEG, 1/10W, 1%, 0603
VISHAY, CRCW06031M00FKEA
16
1
R5
RES., CHIP, 37.4k, 1/10W, 1%, 0603
VISHAY, CRCW060337K4FKEA
17
2
R6, R11
RES., CHIP, 5.11k, 1/10W, 1%, 0603
VISHAY, CRCW06035K11FKEA
18
2
R7, R8
RES., CHIP, 510k, 1/10W, 1%, 0603
VISHAY, CRCW0603510KFKEA
19
1
R9
RES., CHIP, 402k, 1/10W, 1%, 0603
VISHAY, CRCW0603402K0FKEA
20
1
R10
RES., CHIP, 332k, 1/10W, 1%, 0603
VISHAY, CRCW0603332KFKEA
21
1
U1
I.C., LTC3643EUDD, QFN24UDD-3X5
LINEAR TECH., LTC3643EUDD#PBF
Additional Demo Board Circuit Components
1
C6
CAP., ALUM. OPTION,16X16.5
OPT
2
C7, C8
CAP., OPTION, 0603
OPT
3
R12
RES., OPTION, 0603
OPT
Hardware: For Demo Board Only
1
10
E1 – E10
TP, TURRET, 0.094"
MILL-MAX, 2501-2-00-80-00-00-07-0
2
1
JP1
HEADER, 1X3, 0.079 SINGLE ROW
WURTH, 620-003-111-21
3
1
JP2
HEADER, 1X4, 0.079 SINGLE ROW
WURTH, 620-004-111-21
4
2
XJP1, XJP2
SHUNT, 0.079" CENTER
WURTH, 608-002-134-21
4
dc2220afb
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
OFF
ON
E6
E5
E10
E9
E2
JP1
3
2
RUN
1
OPT
R12
47uF
+ C9
C10
4.7uF
1210
Q1
R3
133K
R1
511K
INTVCC
INTVCC
R4
1MEG
SI4491EDY 3
2
1
5
5
1. ALL RESISTORS AND CAPACITORS ARE 0603.
NOTE: UNLESS OTHERWISE SPECIFIED
/PFO
CAPGD
PFI
GND
GND
3V - 17V
VIN
E1
4
510K
R8
510K
R7
R6
5.11K
R5
37.4K
4
C8
OPT
4
5
4
2
1
7
12
11
13
8
6
24
0.01
1210
R2
PGND
PGND
RUN
/PFO
CAPGD
PFI
FBSYS
GATE
CLP
IN
IN
U1
LTC3643EUDD
PGND
SW
SW
SW
INDIS
INDIS
4A
JP2
4
2A
3A
3
2
1
ILIM_BUCK
22
23
INTVCC
C2
4.7uF
0805
C1
0.1UF
L1
7.2uH
21
14
10
9
3
15
20
19
18
17
16
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
2
C4
22pF
2
SCALE = NONE
VK
LT
ECO
C12
10uF
1210
TECHNOLOGY
50V
E7
OPT
E8
GND
CAP
DATE:
N/A
SIZE
LTC3643EUDD
DEMO CIRCUIT 2220A
Tuesday, September 01, 2015
IC NO.
1
SHEET 1
2
OF 1
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
C14
10uF
1210
GND
+ C6
1000uF
+ C5
DATE
9-01-15
LOAD
40V MAX
E4
E3
VK
APPROVED
BIDIRECTIONAL HIGH VOLTAGE BACKUP CONVERTER
TITLE: SCHEMATIC
R11
5.11K
R10
322K
C7
OPT
C15
1uF
100V
0805
C13
10uF
1210
5V SYSTEM BUS
DESCRIPTION
PRODUCTION
2
1
REVISION HISTORY
REV
40V BACKUP
47uF
+ C11
APPROVALS
C3
470pF
R9
402K
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
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
APP ENG.
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
CUSTOMER NOTICE
NC
NC
ILIM
INTVCC
ITH
FBCAP
CAP
BOOST
3
Figure 5. DC2220A Demo Circuit Schematic
25
5
A
B
C
D
DEMO MANUAL DC2220A
SCHEMATIC DIAGRAM
dc2220afb
5
DEMO MANUAL DC2220A
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.
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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,
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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
6
dc2220afb
Linear Technology Corporation
LT 0116 REV B • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
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