ADP1046A 300W Quarter Brick Module

Reference design for uTCA
12V/300W uTCA
PRD1329
FEATURES
300W Full Bridge Topology
Eliminates DC blocking capacitor
Advanced Voltage mode Control with integrated Volt-Second Balance
Remote voltage sensing
Line voltage feedforward
I2C serial interface to PC
Software GUI
Programmable digital filters for DCM and CCM
7 PWM outputs including Auxiliary PWM
Digital Trimming
Current, voltage, and temperature sense through GUI
Calibration and trimming
CAUTION
This evaluation board uses high voltages and currents. Extreme caution must be taken especially on the primary
side, to ensure safety for the user. It is strongly advised to power down the evaluation board when not in use. A
current limited power supply is recommended as input as no fuse is present on the board.
ADP1046 EVALUATION BOARD OVERVIEW
This evaluation board features the ADP1046 in a switching power supply application. With the evaluation board and software,
the ADP1046 can be interfaced to any PC running Windows 2000/XP/Vista/NT via the computer's USB port. The software
allows control and monitoring of the ADP1046 internal registers. The board is set up for the ADP1046 to act as an isolated
switching power supply with a rated load of 12V/25A from an input voltage ranging from a 42 to 60VDC.
Rev. 1.0
Reference designs are as supplied “as is” and without warranties of any kind, express, implied, or
statutory including, but not limited to, any implied warranty of merchantability or fitness for a
particular purpose. No license is granted by implication or otherwise under any patents or other
intellectual property by application or use of reference designs. Information furnished by Analog
Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog
Devices for its use, nor for any infringements of patents or other rights of third parties that may
result from its use. Analog Devices reserves the right to change devices or specifications at any
time without notice. Trademarks and registered trademarks are the property of their respective
owners. Reference designs are not authorized to be used in life support devices or systems.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
©2009 Analog Devices, Inc. All rights reserved.
12V/300W
PRD1329
TABLE OF CONTENTS
Features ....................................................................................................................................................................................... 1
CAUTION ..................................................................................................................................................................................... 1
TOPOLOGY AND circuit description ............................................................................................................................................ 3
CONNECTORS ............................................................................................................................................................................ 3
SETTING FILES AND EEPROM .................................................................................................................................................. 5
BOARD EVALUATION ................................................................................................................................................................. 6
EQUIPMENT ............................................................................................................................................................................ 6
SETUP...................................................................................................................................................................................... 6
BOARD SETTINGS .................................................................................................................................................................. 9
Theory of operation during startup ............................................................................................................................................... 9
FLAGS SETTINGS CONFIGURATIONS ................................................................................................................................ 10
PWM SETTINGS ....................................................................................................................................................................... 11
BOARD EVALUATION AND TEST DATA ................................................................................................................................... 12
STARTUP ............................................................................................................................................................................... 12
PRIMARY GATE DRIVER DEADTIME ................................................................................................................................... 13
CS1 PIN VOLTAGE (PRIMARY CURRENT) .......................................................................................................................... 14
SYnchronous rectifier peak inverse voltage ............................................................................................................................ 15
OUTPUT RIPPLE ................................................................................................................................................................... 15
TRANSIENT Voltage at 48VDC (NOMINAL VOLTAGE) ......................................................................................................... 17
LOAD STEP 0-25A ................................................................................................................................................................. 19
FEEDFORWARD .................................................................................................................................................................... 20
OUTPUT OVER CURRENT PROTECTION ........................................................................................................................... 20
CLOSED LOOP FREQUENCY RESPONSE .......................................................................................................................... 21
EFFICIENCY .......................................................................................................................................................................... 22
CS1 LINEARITY ..................................................................................................................................................................... 22
ACSNS LINEARITY ................................................................................................................................................................... 23
CS2 Linearity .............................................................................................................................................................................. 23
Thermal TEST DATA .................................................................................................................................................................. 24
APPENDIX I – SCHEMATIC (MAIN BOARD) ............................................................................................................................ 25
APPENDIX IV – LAYOUT ........................................................................................................................................................... 28
NOTES ....................................................................................................................................................................................... 31
REVISION HISTORY
10/22/2011—Revision 1.0: SPM
11/28/2011—Revision 1.1: SPM
08/03/2012—Revision 1.2: SPM
12V/300W
PRD1329
BOARD SPECIFICATIONS
Specification
VIN
MIN
TYP
MAX
Units
42
48
60
V
VOUT
10.8
12
13.2
V
IOUT
0.0
25
25
A
0
50
50
ºC
TAMBIENT
Efficiency
93.5%
Switching frequency
148.8
Output Voltage Ripple
%
Notes
With 400 LFM air
flow
Typical reading at
48V/25A load
KHz
100
mV
At 25A load
TOPOLOGY AND CIRCUIT DESCRIPTION
This application note consists of the ADP1046 in a typical DC/DC switching power supply in a full bridge topology with
synchronous rectification. The circuit is designed to provide a rated load of 12V/25A from an input voltage source of 42V to
60VDC. The ADP1046 is used to provide functions such as the output voltage regulation, output over voltage and current
protection, primary cycle by cycle protection, and over temperature protection.
The auxiliary power supply using transformer (T3) and IC (U10) generates 12V rails on both the primary and secondary side to
power the i-couplers and MOSFET drivers. This auxiliary supply starts up at approximately 30VDC.
The primary side consists of the input terminals (JP1, JP3), switches (Q1-Q4), the current sense transformer (T1) and the
main transformer (T2). The ADP1046 resides on the secondary side and is powered via the auxiliary power supply or the USB
connector via the LDO (U11). The gate signal for the primary switches is generated by the ADP1046 through the i-couplers
(U2, U3) and fed into the MOSFET drivers (U1, U4).
The secondary side power stage consists of the synchronous rectifiers (M1, M2, M5, M6). The RCD snubber (D2, D5, C22,
C23, R17, R19, R62, R63) act as snubbers for these FETs. The secondary side FETs are driven by driver (U5). Also present
on the secondary side is the output filter inductor (L3) and the output capacitors (C16-C21). Capacitor (C52) provides high
frequency decoupling to lower EMI.
The primary current is sensed through the CS1 pin with a small RC time constant (R25, C25) that filters the noisy signal. The
secondary current is sense across resistors (R29, R21) and fed in the CS2± pins. The output voltage can be sensed locally or
remotely by removing resistors R23 and R38 and connecting Vsen+ and Vsen- to the remote sensing point on connector
(JP10). Fast OVP is implemented using the VS1 pin and regulation is achieved using VS3 pin. The output voltage is divided to
a nominal of 1V before feeding into the appropriate pins.
Line voltage feedforward is implemented using an RCD circuit (D3, R95, R96, C62, C64) that detects the peak voltage at the
synchronous FET. There are two time constants. The time constants must be matched such that it retains the peak value
during the switching frequency period but also is not too long in case there is a step down change in the input voltage. This
peak voltage is further ratioed and fed in the ACSNS pin of the controller (ADP1046). A thermistor (RT1) is placed on the
secondary side close to synchronous FET and acts thermal protection for the power supply. A 16.5k resistor is placed in
parallel with the thermistor that allows the software GUI to read the temperature directly in degrees Celsius.
Also present on the secondary is a 4 pin connector for I2C communication. This allows the PC software to communicate with
the IC through the USB port of the PC. The user can easily change register settings on the ADP1046, and monitor the status
registers. It is recommended that the USB dongle be connected directly to the PC, not via external hub.
Jumper JP2 acts as a hardware PS_OFF switch. When tied to ground, the voltage reference (D10) stops sinking current,
turning transistor (Q5) off, and thus the optocoupler (U7) off as well. The voltage at the PSON pin is now low and the power
supply is turned off.
CONNECTORS
The following table lists the connectors on the board:
12V/300W
PRD1329
Connector
Evaluation Board Function
JP1
Positive 48V DC Input
JP3
Return for 48V DC Input
JP8
12V isolated output
JP4
Return for 12V DC Voltage Output
JP10
I2C Connector
JP2
Hardware on/off
The pin outs of the USB dongle are given below:
Figure 1 – I2C connector (pin1 on left)
Pin (left to
right)
Function
1
5V
2
SCL
3
SDA
4
Ground
12V/300W
PRD1329
SETTING FILES AND EEPROM
The ADP1046 communicates with the GUI software using the I2C bus.
The register settings (having extension .46r) and the board settings (having extension .46b) are two files that are associated
with the ADP1046 software. The register settings file is contains information such as the over voltage and over current limits,
softstart timing, PWM settings etc. that govern the functionality of the part. The ADP1046 stores all its settings in the EEPROM.
The EEPROM on the ADP1046 does not contain any information about the board, such as current sense resistor, output
inductor and capacitor values. This information is stored in board setup file (extension .46b) and is necessary for the GUI to
display the correct information in the ‘Monitor’ tab as well as ‘Filter Settings’ window. The entire status of the power supply
such as the ORFET and synchronous rectifiers enable/disable, primary current, output voltage and current can be thus digitally
monitored and controlled using software only. Always make sure that the correct board file has been loaded for the board
currently in use.
Each ADP1046 chip has trim registers for the temperature, input current and the output voltage and current, and ACSNS.
These can be configured during production and are not overwritten whenever a new register settings file is loaded. This is
done in order to retain the trimming of all the ADCs for that corresponding environmental and circuit condition (component
tolerances, thermal drift, etc.). A guided wizard called the ‘Auto Trim’ is started which trims the above mentioned quantities so
that the measurement value matches the valued displayed in the GUI to allow ease of control through software.
12V/300W
PRD1329
BOARD EVALUATION
EQUIPMENT
• DC Power Supply (40-60V, 400W)
• Electronic Load (25A/300W)
• Oscilloscope with differential probes
• PC with ADP1046 GUI installed
• Precision Digital Voltmeters (HP34401or equivalent - 6 digits) for measuring DC current and voltage
SETUP
NOTE: DO NOT CONNECT THE USB CABLE TO THE EVALUATION BOARD UNTIL THE SOFTWARE HAS
FINISHED INSTALLING
1)
Install the ADP1046 software by inserting the installation CD. The software setup will start automatically and a guided
process will install the software as well as the USB drivers for communication of the GUI with the IC using the USB
dongle.
2)
Insert the daughter card in connector J5 as shown in Figure 4
3)
Ensure that the PS_ON switch (SW1 on schematic) is turned to the OFF position. It is located on the bottom left half of the
board.
4)
Connect one end of USB dongle to the board and the other end to the board to the USB port on the PC using the “USB to
I2C interface” dongle.
5)
The software should report that the ADP1046 has been located on the board. Click “Finish” to proceed to the Main
Software Interface Window. The serial number reported on the side of the checkbox indicates the USB dongle serial
number. The windows also displays the device I2C address.
5. If the software does not detect the part it enters into simulation mode. Ensure that the connecter is connected to J10 (on
main board) or J7 (on daughter card). Click on ‘Scan for ADP1046 now’ icon (magnifying glass) located on the top right hand
corner of the screen.
12V/300W
PRD1329
5. Click on the “Load Board Settings” icon (fourth button from the left) and select the ADP1046_uTCA_C_xxxx.46b file. This
file contains all the board information including values of shunt and voltage dividers. Note: All board setting files have an
extension of .46b
6. The IC on the board comes preprogrammed and this step is optional. The original register configuration is stored in the
ADP1046_uTCA_C_xxxx.46r register file (Note: All register files have an extension of .46r). The file can be loaded using the
second icon from the left in Figure 6.
7. Connect a DC power source (48VDC nominal, current limit to ~1A) and an electronic load at the output set to 1 Ampere.
8. Connect a voltmeter on test points TP8(+) and TP4(-). Ensure that the differential probes are used and the ground of the
probes are isolated if oscilloscope measurements are made on the primary side of the transformer.
9. Click on the Dashboard settings (3rd icon in Figure 5 and turn on the software PS_ON)
10. The board should now up and running, and ready for evaluation. The output should now read 12 VDC.
11. Click on the ‘MONITOR’ tab and then on the Flags and readings icon. This window provides a snapshot of the entire state
of the PSU in a single user friendly window.
12V/300W
PRD1329
12V/300W
PRD1329
BOARD SETTINGS
The following screenshot displays the board settings.
THEORY OF OPERATION DURING STARTUP
The following steps briefly describe the startup procedure of the ADP1046 and the power supply and the operation of the state
machine for the preprogrammed set of registers that are included in the design kit.
1.
After VDD (3.3V) is applied to the ADP1046 it takes approximately 20µs for VCORE to reach 2.5V. The digital core is
now activated and the contents of the registers are downloaded in the EEPROM. The ADP1046 is now ready for
operation.
2.
PS_ON is applied. The power supply begins the programmed softstart ramp of 40ms (programmable).
3.
Since the ‘softstart from pre-charge’ setting is active the output voltage is sensed before the softstart ramp begins.
Depending upon the output voltage level of the effective softstart ramp is reduced by the proportional amount.
4.
The PSU now is running in steady state. PGOOD1 turns on after the programmed debounce.
5.
If a fault is activated during the softstart or steady state, the corresponding flag will be set and the programmed action
will be taken such as disable PSU and re-enable after 1 sec, Disable SR and OrFET, Disable OUTAUX etc.
12V/300W
PRD1329
FLAGS SETTINGS CONFIGURATIONS
Basically when a flag is triggered, the ADP1046 state machine waits for a programmable debounce time before taking any
action. The response to each flag can be programmed individually. The flags can be programmed in a single window by hitting
the FLAG SETTINGS icon in the MONITOR tab in the GUI. This monitor window shows all the fault flags (if any) and the
readings in one page. The ‘Get First Flag’ button determines the first flag that was set in case of a fault event.
12V/300W
PRD1329
PWM SETTINGS
The ADP1046 has a fully programmable PWM setup that controls 7 PWMs. Due to this flexibility the IC
can function in several different topologies such as any isolated buck derived topology, push pull,
flyback and also has the control law for resonant converters.
The integrated volt-second balance feature is used as a current balancer of the two legs of the full
bridge topology.
Each PWM edge can be moved in 5ns steps to achieve the appropriate deadtime needed and the
maximum modulation limit sets the maximum duty cycle.
PWM
Switching element being controlled
OUTA-OUTD
Primary switch PWM
SR1-SR2
Synchronous rectifier PWMs
OUTAUX
N/A
12V/300W
BOARD EVALUATION AND TEST DATA
STARTUP
PRD1329
12V/300W
PRIMARY GATE DRIVER DEADTIME
PRD1329
12V/300W
CS1 PIN VOLTAGE (PRIMARY CURRENT)
PRD1329
12V/300W
SYNCHRONOUS RECTIFIER PEAK INVERSE VOLTAGE
OUTPUT RIPPLE
PRD1329
12V/300W
PRD1329
12V/300W
TRANSIENT VOLTAGE AT 48VDC (NOMINAL VOLTAGE)
LOAD STEP OF 0-25%
LOAD STEP OF 25-50%
PRD1329
12V/300W
LOAD STEP OF 50-75%
PRD1329
12V/300W
LOAD STEP OF 75-100%
LOAD STEP 0-25A
PRD1329
12V/300W
FEEDFORWARD
OUTPUT OVER CURRENT PROTECTION
PRD1329
12V/300W
PRD1329
CLOSED LOOP FREQUENCY RESPONSE
A network analyzer (AP200) was used to test the bode plots of the system. A continuous noise signal of 300mV
was injected across the entire frequency range across R35 using an isolation transformer with R38 shorted. The
operating condition was 48VDC input and a load condition of 25A.
12V/300W
EFFICIENCY
CS1 LINEARITY
PRD1329
12V/300W
ACSNS LINEARITY
CS2 LINEARITY
PRD1329
12V/300W
PRD1329
THERMAL TEST DATA
A thermal snapshot of the unit was taken after running at 25A for 1 hour of soaking time with air flow of
200LFM.
12V/300W
PRD1329
APPENDIX I – SCHEMATIC (MAIN BOARD)
CS+
Vin+
1
1
2
1
3
Vin+
T1
Q1
BSC060N10NS3
8
6
5
4
7
JP1
PA1005.100NL
R1
4.7
R2
10K
R3
4.7
Q3
BSC060N10NS3
R4
10K
T2
7
Gate1 SW1
C2
C60
1.5uF 1.5uF
C1
C4
1.5uF 1.5uF
C5
1.5uF
Gate3
1
C6
1.5uF
SW2
6
5
TR5
4
TR4
3
TR3
2
RM8
Q2
BSC060N10NS3
Q4
BSC060N10NS3
3V3_SEC
Vin+
R5
4.7
R6
10K
R7
4.7
R8
10K
VinCS+
AGND
Vin-
1
1
Vin-
Gate2
Gate4
PGND
JP3
12V_PRI
C7
0.1uF
VDD
HB
HO
HS
NC1
10
9
8
7
6
LO
VSS
LI
HI
NC2
11
SW1
1
2
3
4
5
PAD
Gate1
OUTA
U1 Gate2
LM5101A
R9
0
5V_PRI
R10
0
C8
0.1uF
VDD2VDD1
VOA
VIA
VOB
VIB
GND2GND1
OUTB
3V3_SEC
U2
8
7
6
5
OUTC
1
2
3
4
OUTA
OUTB
12V_PRI
C9
0.1uF
ADUM3200
C10
1uF
OUTD
5V_PRI
TR5
TR4
Gate4
VDD
HB
HO
HS
NC1
LO
VSS
LI
HI
NC2
PAD
C11
0.1uF
U4
11
Gate3
SW2
1
2
3
4
5
C14
1uF
TR3
10
9
8
7
6
LM5101A
R11
0
5V_PRI
8
7
6
5
R12
0
C12
0.1uF
3V3_SEC
U3
VDD2VDD1
VOA
VIA
VOB
VIB
GND2GND1
ADUM3200
1
2
3
4
OUTC
OUTD
C13
0.1uF
0
Vin+
VinCS+
AGND
PGND
OUTA
OUTB
OUTC
OUTD
12V_PRI
3.6V_SEC
0
12V_PRI
3V3_SEC
5V_PRI
TR5
TR4
TR3
12V/300W
PRD1329
L3
2.3uH
Vout+
TR4
1
Vout+
1
JP8
M1
BSC047N08NS3
TR5
CS2-
CS2-
CS2+
M2
BSC047N08NS3
CS2+
1
VSS
VSS
VSO
D2
MURA110
C17
2
C16
10uF/16V
10uF/16V
C18
68uF
CMAX
VSO
Vout+
Vout+
VoutR58
2
R59
R14
2
Vout-
TR7
R19
10K
10K
TR7
TR6
TR6
TR5
10K
R17
M5
BSC047N08NS3
TR3
R62
TR5
TR4
C20
C19
10uF/16V
10K
C21
68uF
CMAX
10uF/16V
TR4
TR3
TR3
SR1
SR1
SR2
M6
BSC047N08NS3
C22
33nF
R63
10K
SR2
PSON
CS2-
PSON
CS2+
12V_SEC
12V_SEC
PGND
R60
2
R61
2
D5
MURA110
1
2
R18
10K
C23
33nF
R29
2m
R21
2m
PGND
AGND
R31 R28
4.99K 4.99K
0.1% 0.1%
VSS
PGND
1
1
AGND
Vout-
JP4
VSS
R22
10
PSON
#OTW
U5
ADP3634
EN
INA
GND
INB
PAD
12V_SEC
OTW
OUTA
VS
OUTB
1
2
3
4
SR1
C24
1uF
SR2
R87
0
9
8
7
6
5
VSS
T3
Vin+
1
D15
BAV70WT1
VSS
12V_SEC
R77
20K
R76
20K
C41
470pF/250V
D16
MMBD1504A
Vin+
12V_PRI
2
3
5
4
C43
10uF/16V
12V_PRI
5V_PRI
R88
1K
3.6V_SEC
5V_PRI
3V3_SEC
3
R78
1M
VSS
Vin+
6
3V3_SEC
12V_SEC
12V_SEC
ER11
EN_LDO
D17
BAV70WT1
VD GND
VCC CT
UV VFB
OV COM
U10
9 PAD
1
2
3
4
R79
20K
C47
0.1uF
C50
1nF
R83
10K
R80
680
C49
R82
5.1K
C48
R81
680
D8
1N4148WS
Vin-
2
3.6V_SEC
3.6V_SEC
5V_PRI
12V_VCC
C51
0.1uF
R84
55K
C52
1000pF/2000V
12V_SEC
U11
3V3_SEC
1
2
3
EN_LDO4
2
1
VSS
C53
220pF
PGND
Vin-
0
3
C46
0.1uF
8
7
6
5
AGND
PGND
D19
MMBZ5227BL/3.6V
10uF/16V
12V_VCC
C45
390pF
10uF/16V
NCP1031
EN_LDO
AGND
1
12V_PRI
D18
MMBZ5231BLT/5.1V
R85 10K
R86
36K
GND
IN
OUT
EN
GND4
GND3
GND2
GND1
8
7
6
5
ADP1720ARMZ-3.3-R7
AUX Power
C54
1uF
C55
1uF
C56
0.1uF
3.3V LDO
0
12V/300W
PRD1329
VSO CS2-
D6
BAS21W-7-F
200V
CS2+
R96
47
Vout+
R25
680
R30
10
R44
10
C25
100pF
Vout+
R23
10
C62
2200pF
Vsen+
R74
DNI
VS1
R27
4.7K
D3
MURA110
TR3
C64
2200pF
R24
11K
R26
14.7K
CS+
R95
100
VSO
VS3+
TR3
C58
1nF
C66 1000pF
R32
1K
PGND
R35
11K
R33
1K
C65 1000pF
TR3
CS2-
CS2-
CS2+
CS2+
VSO
VSO
VS3+
SR1
R71
10K
SR2
Vout+
R73
10K
C59
1nF
0
Vout+
Vout-
R37
1K
Vout-
16
1
VS3+
VS3-
7
CS1
VCORE
R38
32
OUTA
12
OUTB
13
OUTC
14
OUTD
OUTAUX
15
VDD
31
DGND
ADP1046
OUTC
AGND
OUTD
TPAD
C63
0.1uF
PGOOD1
PSON
C26
0.47uF
25
33
R93
2.2K
Share
23
PGND
JP9
SHORTPIN
0
AGND
0
AGND
OUTD
3V3_SEC
12V_SEC
JP10
R67
100
R43
2.2K
0
0
C29
33pF
D4
1N4148WS
C31
33pF
0
1
3
5
7
2
4
6
8
PGOOD
Vsen+
VsenR66
0
5V
0
R70
100
C30
33pF
0
R65
16.5K
OUTC
SDA
24
SCL
2
3V3_SEC
3V3_SEC
12V_SEC
R68
0
PGND1
OUTB
OUTD
0
PGND
OUTA
OUTB
OUTC
C28
33pF
R42
10K 0.1%
0
PGOOD
OUTA
0
2
SDA
R41
10K 0.1%
C27
0.33uF
PSON
TR4
PGND
R39
2.2K
18
17
30
SCL
RES
ADD
RTD
R40
2.2K
ADD 29
3V3_SEC
28
22
PGOOD2
FLAGIN
21
20
PSON
19
R64
10K
SHAREi
SR2
TR4
27
AGND
SR1
SR2
PSON
OUTAUX
SHAREo
SR1
26
OUTA
OUTB
10
VS3-
3V3_SEC
11
CS+
AGND
GATE
VS2
3
PGND
VS1
8
5
CS2-
CS2+
4
10
SR2
9
ACSNS
U6
SR1
6
CS+
Vsen-
Connector
R45 2
DNI
ADD
R34
DNI
Share
12V_SEC
0
RT1
100KOhm
DGND
R69
0
0
5V_PRI
Ven
CS+
R46
220K
R49
10K
3V3_SEC
R50
5.1K
R51
8.2K
Ven
R52
1K
ON/OFF
1
1
JP2
R57
220
R53
5.1K
C33
10nF
R54
5.1K
Vin+
U7
PS2911
2
D11
BAV70WT1
C32
1uF
CS+
EN_LDO
3V3_SEC
3.6V_SEC
1
D10
ZR431F01
Q5
MMBT2907AW1
4
R48
100K
PSON
3
Vin+
EN_LDO
R47
1K
R55
220
Vin5V_PRI
R56
5.1K
C34
10nF
C35
10nF
PSON
AGND
0
3.6V_SEC
OUTAUX
R36
Vin+
Vin5V_PRI
PSON
AGND
3.6V_SEC
12V/300W
PRD1329
APPENDIX IV – LAYOUT
The layout of the board was done on 14 layers with 3 ounce copper on the external layers. Some of the layers are shown
below.
12V/300W
PRD1329
12V/300W
PRD1329
12V/300W
NOTES
PRD1329
©2009 Analog Devices, Inc. All rights reserved.
Trademarks and registered trademarks are the
property of their respective owners.
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