PowerBox Defense Series User manual

POWERBOX Defense Line
OFD1200A Series
1200W Single output
AC/DC Baseplate power supply
1
www.prbx.com PBSE10273731A 2023.10-11
Specifications are subject to change without notice.
Table of Contents
1. Assembling and Installation Method ......................................................... 1
1.1 Mounting method ................................................................................... 1
1.2 Isolation from conductive enclosure.................................................... 2
1.3 Installation to fulfil EMC requirement.................................................. 2
2. Derating........................................................................................................... 2
2.1 Derating curve by input voltage............................................................ 2
2.2 Temperature measuring point.............................................................. 2
3. Wiring .............................................................................................................. 3
3.1 Wiring input connector .......................................................................... 3
3.2 Wiring output terminal ........................................................................... 3
3.3 Wiring function connector..................................................................... 3
3.4 Jumper factory setting........................................................................... 3
3.5 Output ripple and ripple noise measurement .................................... 4
4. Functions ........................................................................................................ 4
4.1 Input voltage range................................................................................. 4
4.2 Inrush current limiting............................................................................ 4
4.3 Over current protection.......................................................................... 4
4.4 Over voltage protection.......................................................................... 4
4.5 Thermal protection ................................................................................. 4
4.6 Output voltage adjustment.................................................................... 4
4.7 Remote ON/OFF..................................................................................... 5
4.8 Remote sensing....................................................................................... 6
4.9 Adjustable constant current range ...................................................... 7
4.10 Power good (PG)................................................................................... 7
5. Series / Parallel Operation........................................................................... 8
5.1 Series operation ...................................................................................... 8
5.2 Parallel operation .................................................................................... 8
5.3 Redundancy operation.........................................................................10
6. Life Expectancy and Warranty...................................................................10
6.1 Life Expectancy .....................................................................................11
6.2 Warranty .................................................................................................11
7. Options..........................................................................................................11
7.1 Option -O: with Active ORing..............................................................11
1. Assembling and Installation Method
1.1 Mounting method
OFD1200A series should be mounted to a heatsink or enclosure which
has sufficient thermal capacity to be cooled by conduction cooling.
OFD1200A has 12 of 4.5mm diameter mounting holes, to keep
uniform thermal conductivity, use all holes as shown in Fig. 1.1.
Fig. 1.1 Mounting hole requirement
A thermal interface material such as thermal pads or thermal grease
shall be used to ensure proper cooling of the power supply.
OFD1200A28 and OFD1200A48 without option -O (Active ORing),
and OFD1200A65 have open holes in the aluminium baseplate. When
using grease as thermal interface material, it could flow to the inside of
unit. This is not dangerous, but not desirable. We recommended to not
apply grease closer than 10mm from these holes. See Fig. 1.2 for
location of open holes.
Fig. 1.2 The Location of open hole on aluminium baseplate (Bottom
view)
Remarks:
- There are no open holes in the aluminium baseplate on some
models. Please refer to Table 1.1 to clarify the differences.
Table 1.1 Holes on the baseplate by models
Model
Holes
OFD1200A12-N
No holes
OFD1200A28-NO
No holes
OFD1200A28-N
Holes
OFD1200A48-NO
No holes
OFD1200A48-N
Holes
OFD1200A65-N
Holes
23.5mm
80mm
12mm
32mm
20mm
Output
Input
Location of open holes

POWERBOX Defense Line
OFD1200A Series
1200W Single output
AC/DC Baseplate power supply
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1.2 Isolation from conductive enclosure
There are dangerous voltages inside of the unit. Special attention
needs to be considered when installing the unit.
Ensure proper isolation distances between the components and
conductive enclosure.
d1, d2 = 4mm min
Fig. 1.3 Isolation distance
To optimize cooling airflow around the unit, ensure that the clearance
between the unit and surrounding objects is as large as possible.
1.3 Installation to fulfil EMC requirement
To ensure the best EMI-performance, the equipment should be
mounted inside an earthed metal box.
If it is not possible, install the unit and the load on an earthed metal
plate.
Input cables should be twisted and places as close to the metal
enclosure as possible.
Output cables of positive (+) and negative (-) should be twisted and
shall be separated from input cables as much as possible.
If radiation from input or output cables are an issue, use appropriate
EMC ferrite clamp on the cables.
When function pins are connected to an user accessible point (i.e.,
panel switch, indicator circuit etc.), these must be protected from
electrostatic discharging.
2. Derating
2.1 Derating curve by input voltage
Fig. 2.1 Derating curve by input voltage
Remarks:
- OFD1200A12-N has no input voltage derating.
- The over current protection will be activated as following Fig.2.1.
2.2 Derating curve by ambient and baseplate temperature
For reliable and safe operation, follow the derating curve shown in Fig.
2.2 and Fig. 2.3. The measurement point of baseplate is shown in Fig.
2.4. The curve is set based on 3-years life expectancy.
Fig. 2.2 Derating curve by ambient temperature
Fig. 2.3 Derating curve by baseplate temperature
Fig. 2.4 Measurement point of baseplate (Bottom view)
Remarks:
Operation in the hatched defers level of the ripple and noise.
d1
d1
d2
(Side view)
(Top view)
0
50
100
-40 -20 0 20 40 60 80 100
Load factor [%]
Baseplate temperature [˚C]
(75)
(75)
(65)
(95)
(60)
OFD1200A28, OFD1200A48 (Vin = 170～305VAC)
OFD1200A28, OFD1200A48 (Vin = 85～170VAC) and,
OFD1200A65 (Vin = 85～305VAC)
OFD1200A12 (Vin = 85～305VAC)
0
50
100
-40 -20 0 20 40 60 80 100
Load factor [%]
Ambient temperature [˚C]
OFD1200A12,OFD1200A28,
OFD1200A48,OFD1200A65
Vin = 85～305VAC
(60)

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OFD1200A Series
1200W Single output
AC/DC Baseplate power supply
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3. Wiring
3.1 Wiring input connector
(1) Built-in fuse
The two 16A AC fuses are built-in on AC(L) in parallel.
(2) Wire
Connection capability of the input connector.
Input connector type : MKDS 5/ 3-9,5 (1714984)
(Phoenix Contact)
Connector cross section solid : 0.2 mm2–6 mm2
Connector cross section flexible : 0.2 mm2–4 mm2
Conductor cross section (AWG) : AWG 24 –10
Conductor cross section (flexible, with ferrule)
: 0.25 mm2–4 mm2
Stripping length : 8mm
Torque : 0.5 –0.6 Nm
An input current is dependent on input voltage and output current.
Choose the appropriate thickness for the input wire.
Influence against noise is improved if the input wires are twisted. In
addition, make sure that input and output wires are separated.
(3) FG terminal
The FG terminal on input connector shall be Functional Ground.
Make sure that the mounting hole for protective earthing on the
baseplate is properly connected, as required for class I equipment.
3.2 Wiring output terminal
The assembly torque for output terminal screws.
Screw size : M6
Recommended screw torque : 3.8 Nm
At -40°C operation, an external output capacitor needs to be added to
ensure stable output voltage during start-up. Table 3.1 shows a
recommended external output capacitor.
Table 3.1 Recommended external output capacitor
Models
Value
OFD1200A12-N
7,800 µF
OFD1200A28-N and -NO
3,000 µF
OFD1200A48-N and -NO
1,360 µF
OFD1200A65-N
Not needed
3.3 Wiring function connector
Fig. 3.1 shows the pin assignment and Table 3.2 states the pin
configuration of function connector X506 and X507.
Fig. 3.1 X506 and X507 Pin assignment
Table 3.2 Function of connector X506 and X507
Pin No.
Name
Function
1
CB
Refer to Section 5.2
2
-S
Refer to Section 4.8
3
PG
Refer to Section 4.10
4
RC1
Refer to Section 4.7
5
ITRM
Refer to Section 4.9
6
VTRM
Refer to Section 4.6
7
NC
8
PGG
Refer to Section 4.10
9
+S
Refer to Section 4.8
10
RC2
Refer to Section 4.7
<Connector information>
Part number : 87831-1041 (Molex)
<Appropriate mating connector and pin>
Part number : 51110-1056 (Molex)
Pin : 50394-8051 (Molex)
For connecting X506 and X507, optional cable H-SN-61
(Manufactured by Cosel) is available.
https://en.cosel.co.jp/product/optionparts/H-SN-61/
Remarks:
- An incorrect connection of functional connector may cause damage
on an internal circuit. Make sure the connection is properly made.
3.4 Jumper factory setting
Jumpers on X503, X504 and X601 are placed as shown in Fig. 3.2 at
the factory.
Fig. 3.2 Jumper placement at factory
9
10
2
1
Input side
of the unit
Output side
of the unit
CB
PG
ITRM
NC
+S
-S
RC1
VTRM
PGG
RC2

POWERBOX Defense Line
OFD1200A Series
1200W Single output
AC/DC Baseplate power supply
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3.5 Output ripple and ripple noise measurement
The specified ripple and ripple noise are measured by the method
shown in Fig.3.3.
Fig.3.3 Method of Measuring Output ripple and ripple noise
Remarks:
- When the ambient temperature is lower than -20°C, the output ripple
may become unstable during heating up.
4. Functions
4.1 Input voltage range
The unit operates with an input voltage range between 85 - 305 VAC.
The voltage range for a valid safety approval is 100 - 277 VAC
(50/60Hz).
Remarks:
- Be aware that use of voltages other than those listed above may
result in the unit not operating according to specifications or may
cause damage or dangerous situations. Avoid square waveform input
voltage, commonly used in UPS and inverters.
4.2 Inrush current limiting
There is a built-in inrush current limiting circuit.
If a switch is needed on the input side, select one that can withstand
the input inrush current.
The thyristor technique is used in the inrush current limiting circuit.
Avoid repeatedly turning the power ON/OFF within a short period of
time, operates the inrush current limiting becomes inoperative.
When the input power is turned on, the primary inrush current and
secondary inrush current will be generated due to the thyristor
technique used for the inrush current limiting circuit.
4.3 Over current protection
The over current protection is built in and comes into effect when
drawing over 105% of the rated current.
The over current protection prevents the unit from short circuit and
over current condition. The unit automatically recovers when the fault
condition is cleared.
When the output voltage drops at over current, the average output
current is reduced by hiccup operation of the unit.
4.4 Over voltage protection
The over voltage protection circuit is built in. If the over voltage
protection circuit is activated, shut down the input voltage, wait a
certain time and turn on the AC input again to recover the output
voltage.
The recovery time is 10 seconds or more.
Remarks:
- Note that devices inside the unit might fail if voltage of higher than
rated output voltage is applied to output terminal. This could happen
when the user tests the over voltage performance of the unit.
- With option -O (Active ORing) circuit disconnects the output from the
external voltage. Therefore, over voltage protection will not be
activated. Therefore, it is not possible to test over voltage performance
for an option -O unit by applying external voltage.
4.5 Thermal protection
When the baseplate temperature exceeds the maximum temperature,
thermal protection will be activated and shut down the output.
When the thermal protection is activated, turn off the input voltage and
eliminate all the overheating conditions. To recover the output voltage,
let the unit cool down before turning on the input voltage again.
4.6 Output voltage adjustment
The output voltage can be adjusted by means of either the built-in
potentiometer (R513) or by applying an external voltage source.
(a) Adjustment by built-in potentiometer
To increase output voltage, turn R513 clockwise. To decrease the
output voltage, turn it counter clockwise.
The output voltage adjustment range by R513 is shown below.
Model Output
Number Voltage adj.
OFD1200A12-N 4.2 –14.4VDC
OFD1200A28-N and -NO 9.8 - 33.6VDC
OFD1200A48-N and -NO 16.8 - 57.6VDC
OFD1200A65-N 22.8 –78.0VDC
OFD1200A Load
C1
C2
+Vout
-Vout
300mm
Oscillo
scope
+
1.5m 50Ω
Coaxial Cable
C3
R
C1 : 0.1µF
C2 : 47µF
C3 : 4,700pF
R : 50Ω

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OFD1200A Series
1200W Single output
AC/DC Baseplate power supply
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(b) Adjustment by external voltage source
To adjust the output voltage by an external voltage source, apply it
between VTRM and -S terminal.
Use a low impedance source as external voltage. The internal circuit of
VTRM is shown in Fig. 4.1.
WARNING:
Adjusting the built-in potentiometer (R513) fully counter clockwise and
applying external voltage may damage the unit.
The output voltage must be adjusted within ±20% of the nominal by
R513 before applying external voltage.
Do not apply an external voltage lower than -0.3V or greater than 5.0V.
Fig. 4.1 VTRM internal circuit
The output voltage can be calculated by the following equation when
the voltage is applied to the VTRM terminal.
Output voltage [V]=
The voltage between
VTRM and -S [V]
2.5 [V] ×Rated output voltage [V]
Fig. 4.2 Output Voltage by VTRM
4.7 Remote ON/OFF
Remote ON/OFF is built in. Remote ON/OFF is operated by applying a
voltage between RC1 and RC2 terminal. The Internal circuit and
function of X601 are shown in Fig. 4.3.
When the output shuts off by the over voltage protection or thermal
protection, it can be recovered by toggling Remote ON/OFF signal.
The remote control logic can be changed with X601. And the isolation
between the RC circuit and any other is dependent on the position of
X601’s jumper. Those details are shown in Table 4.1 and Fig. 4.4.
Table 4.1 Remote Control Logic
No.
Item
Remote Control Logic
1
Connection
method
Fig. 4.4(a)
Fig. 4.4(b)
Fig. 4.4(c)
2
Isolation
INPUT - RC
OUTPUT - RC
INPUT –RC
INPUT - RC
3
Reference
pin
RC2
-S
-S, RC2
4
Output
ON
SW OPEN (0.1mA max)
SW SHORT
(0.5V max)
5
Output
OFF
SW SHORT (2mA min)
SW OPEN
(0.1mA max)
Fig. 4.3 The Internal circuit and function of X601
OFD1200A
VTRM
-S
5V
4.7kΩ
10kΩ
0.01uF
R513:
10k
External voltage source
Vref
680Ω
OFD1200A
150
RC1
RC2
-S
Jumper
Internal AUX
12V typ.
X601
3.3k
(a) The position of jumper:
OFD1200A
150
RC1
RC2
-S
Jumper
Internal AUX
12V typ.
X601
3.3k
(b) The position of jumper:

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OFD1200A Series
1200W Single output
AC/DC Baseplate power supply
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(a) Use external voltage source (Positive logic)
External resistor Rrc value shall be decided by following formula.
Vext[V]-1.4
2[mA] -150[Ω] > Rrc[Ω]> Vext[V]-0.9 12[mA] -150[Ω]
(b) Change position of X601 (Positive logic)
In the case of this connection example, the control current (I_RC1)
flows up to 3.5mA.
(c) Change position of X601 (Negative logic)
In the case of this connection example, the control current (I_RC1)
flows up to 3.5mA.
Fig. 4.4 Example of connecting remote ON/OFF circuit
Remarks:
- Be careful not to connect RC1 and RC2 opposite. It may cause a
failure of unit.
- The sink current of RC1 must be kept up to 12mA.
- Do not use RC1 terminal any other purposes except remote control.
4.8 Remote sensing
Remote sensing is built in. When remote sensing is not used, make
sure that jumpers are placed on X503 and X504 as shown in Fig.
4.5(a).
When using remote sensing function, place jumpers on X503 and
X504 as shown in Fig. 4.5(b), then connect +S and -S terminal on X506
or X507 to sensing point.
Fig. 4.5 X503 and X504 Jumper position
Remarks:
- Twisted-pair wires or shielded wires should be used for sensing wire.
- Use proper cable thickness for the wiring between the unit and load.
The line drop between the unit and load should be less than 0.5V. The
voltage between +Vout and -Vout should remain within the output
voltage adjustment range.
- If the sensing lines become short circuited, a high current will occur,
and the sensing circuit may be damaged. The problem can be
prevented by installing current limiting the component near the load.
- As wiring or load impedance may generate oscillation or large
fluctuation in output voltage, make sure enough evaluation is given in
advance. If the unstable condition occurs, try adding C1 –C3 and R1.
Fig. 4.6 When using remote sensing function
OFD1200A Load
C2
+Vout
-Vout
+
-S
+S
R1
Wire the sensing lines as close as possible
C1
+
+
C3
OFD1200A
RC1
RC2
-S
Vext
Rrc
ON
OUTPUT
OFF
X601 Position
OFD1200A
RC1
RC2
-S
ON
OUTPUT
OFF
X601 Position
OFD1200A
RC1
RC2
-S
OFF
OUTPUT
ON
X601 Position
(a) Disable remote sensing
(Factory setting)
(b) Enable remote sensing
C1 –C3: 100 –2,200 [μF]
R1: 1 –4.7 [Ω]
I_RC1
I_RC1

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OFD1200A Series
1200W Single output
AC/DC Baseplate power supply
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4.9 Adjustable constant current range
The output current for the constant current can be adjusted by
connecting external resistors to ITRM or by applying a voltage
externally. Meanwhile, the Hiccup mode of the short circuit protection
will be disabled.
(1) Constant current adjustment by potentiometer
By connecting the external potentiometer as shown in Fig. 4.7, output
current for constant current becomes adjustable.
Wiring to the potentiometer should be as short as possible. As the
ambient temperature fluctuation characteristics deteriorate
depending on the types of resistors and potentiometers, use resistors
and a potentiometer of the following specifications:
Potentiometers: Cermet type, coefficient less than ±300ppm/℃
Fig. 4.7 Connection for CC by external potentiometer
(2) Constant current adjustment by external voltage
By applying a voltage externally to ITRM, output current for constant
current becomes adjustable.
When the ITRM terminal voltage is set at less than 2.5 V, the constant
current set value can be changed.
Output current [A]=
The voltage between
ITRM and -S [V]
2.5 [V] ×Rated output current [A]
Fig. 4.8 ITRM internal circuit
Remarks:
- If the output voltage becomes less than 5% of the rated voltage
during constant current operation, the output voltage may become
unstable.
- When the output current adjustment is not used, keep ITRM pin
open.
- Do not set the external applied voltage to -0.3 V or less, and 5.0 V or
more.
4.10 Power good (PG)
By using power good signal (PG), it is possible to monitor the unit
whether normal operation or abnormal operation. The PG signal is
“Low” when the unit operates correctly. The signal turns to “High”
when the unit stops.
The PG circuit is designed as shown in Fig. 4.9. The sink current of PG
is 1mA max.
The circuit of the PG (PG, PGG) is isolated from input, output, FG, and
various function terminals.
Fig. 4.9 Internal circuit of PG
The details of PG signal are shown in Table4.3, Fig. 4.10, and Fig.
4.11.
Table 4.3 Specification of PG
No.
Item
PG
1
Function
Normal operation “Low”
The unit stops “High”
2
Base pin
PGG
3
Level voltage “L”
0.5V max at 1mA
4
Level voltage “H”
Open collector
5
Maximum sink current
1mA max
6
Maximum applied voltage
50V max
Fig. 4.10 PG signal sequence
ACin
ON
RC
OFF
RC
ON
Adjustable
Constant
Current
Adjustable
Volgate
ACin
OFF
CC-control
CV-control
V1: 60% of the set output voltage
V2: 20% of the set output voltage
0V
0V
V1
V2
OFF
ON
Hight
Low
12V typ.
0V
AC Input
voltage
Output
voltage
Remote
ON/OFF
PG
Internal
AUX
OFD1200A
ITRM
-S
External potentiometer
10[kΩ]

POWERBOX Defense Line
OFD1200A Series
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Fig. 4.11 PG signal sequence with circuit protections
5. Series / Parallel Operation
5.1 Series operation
Series operation is possible by connecting the output of two or more
power supplies as shown in Fig. 5.1.
Fig. 5.1 Example of Series operation
Output current in series connection should be lower than the lowest
rated current in each unit.
When one of unit’s output becomes short circuit in series operation,
high voltage may be applied to rest of units. To avoid further damages,
consider adding a protection method that immediately stops
operation.
Make sure that the combined total output voltage is less than 120Vdc.
The classification of Electrical energy source of output voltage for
OFD1200A12 and OFD1200A28 are ES1, and OFD1200A48 and
OFD1200A65 are ES2. Therefore, make sure the safety requirement
when total output voltage exceeds 60Vdc.
5.2 Parallel operation
(a) Wiring for parallel operation
Parallel operation is possible by connecting the units as shown in Fig.
5.2 and Fig. 5.3. Terminal -S, CB, and VTRM of function connecter
X506 or X507 of each unit must be connected to each other.
To wire the terminal -S, the jumper position of X504 must be changed
for all units as Fig. 5.2 and then, the cable must be connected to -Vout
from only one unit shown as Fig.5.3. The cables must be twisted or
bundled with a cable of CB and VTRM. If not, the output voltage may
become unstable or fluctuate.
If the temperatures of aluminium baseplate are different in the unit in
parallel operation, the difference of output current becomes large.
Consider the thermal design to equalize aluminium baseplate
temperatures.
(i.e., attaching a single heatsink etc)
Total current must not exceed the value calculated by the following
equation, and total number of units should be no more than 9 pieces.
(Output current at parallel operation)
= (the rated current per unit) x (number of unit) x 0.9
Fig. 5.2 X504 Jumper position
Fig. 5.3 Example of wiring for parallel operation
(a)
(b)
ACin
ON
OTP Over Current
Protection
V1: 60% of the set output voltage
V2: 20% of the set output voltage
RC
ON
RC
OFF
OVP
RC
ON
RC
OFF
Hiccup
0V
0V
V1
V2
OFF
ON
Hight
Low
12V typ.
0V
AC Input
voltage
Output
voltage
Remote
ON/OFF
PG
Internal
AUX
OFD1200A
N
L
FG
OFD1200A
N
L
FG
OFD1200A
N
L
FG
Load
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
AC IN
FG
VTRM
VTRM
VTRM
Wire as close as possible
Wire as close as possible
(a) Factory setting
(b) For wiring parallel operation

POWERBOX Defense Line
OFD1200A Series
1200W Single output
AC/DC Baseplate power supply
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Specifications are subject to change without notice.
Remarks:
- Make sure that the wiring impedance of a load from each unit
becomes even.
- A voltage drop from -Vout of unit to the connected point of terminal -
S should be less than 0.5V for stable control.
- If the output current is less than 2% of the rated current, the output
voltage ripple will be large.
- If all paralleled unit need to start up at the same time, remote control
function shall be used.
(b) Output voltage adjustment in parallel operation
The output voltage can be adjusted by the built-in potentiometer
(R513) or by applying an external voltage source in parallel operation.
By using R513, it is possible to adjust all output voltages in the unit by
the master unit. Select one unit as the master and turn the R513 of the
other unit (slave) clockwise to the maximum output voltage adjustment
following the datasheet.
By using an external voltage source, the examples of circuits are
shown in Fig. 5.4. Refer to section 4.6 ”Output voltage adjustment”
how to use this function.
Fig. 5.4 Example of connecting output voltage adjustment circuit with
external voltage in parallel operation
(c) Wiring for parallel operation with remote sensing
Example of connecting remote sensing circuits in parallel operation
are shown in Fig. 5.5. Refer to section 4.8 "Remote sensing" how to
use this function.
Fig. 5.5 Example of connecting remote sensing circuit
(d) Wiring for parallel operation with remote control
Example of connecting remote ON/OFF circuits in parallel operation
are shown in Fig. 5.6 and Fig. 5.7. Refer to section 4.7 "Remote
ON/OFF" how to use this function.
In this case, accumulated current (N×I_RC1) flows to the control
switch.
Fig. 5.6 Example of connecting remote ON/OFF circuit
Fig. 5.7 Example of connecting remote ON/OFF circuit
OFD200A
OFD1200A Load
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
VTRM
VTRM
Vref
Wire as close as possible
External voltage source
OFD1200A
OFD1200A Load
+Vout
-Vout
-S
+S
CB
+Vout
-Vout
-S
+S
CB
Sensing point
VTRM
VTRM
Wire as close as possible
OFD1200A
RC1
RC2
-S
X601 Position
・・・
OUTPUT
ON
OFF
N x I_RC1
OFD1200A
RC1
RC2
-S
X601 Position
OFD1200A
RC1
RC2
-S
X601 Position
I_RC1
I_RC1
I_RC1
・・・
Vrc
OUTPUT
ON
OFF
N x I_RC1
I_RC1
I_RC1
I_RC1
Rrc
OFD1200A
RC1
RC2
-S
X601 Position
Rrc
OFD1200A
RC1
RC2
-S
X601 Position
Rrc
OFD1200A
RC1
RC2
-S
X601 Position

POWERBOX Defense Line
OFD1200A Series
1200W Single output
AC/DC Baseplate power supply
10
www.prbx.com PBSE10273731A 2023.10-11
Specifications are subject to change without notice.
(e) Wiring for parallel operation with constant current adjustment
The constant current adjustment can be used in parallel operation. By
changing the ITRM voltage of one unit, the constant current adjustable
for all of units.
It is not necessary to connect the ITRM terminals together. Examples
of connecting constant current circuit in parallel operation are shown
in Fig. 5.8 and Fig. 5.9. Refer to section 4.9 "Adjustable constant
current range " how to use this function.
Fig. 5.8 Example of connecting constant current circuit with a
potentiometer
Fig. 5.9 Example of connecting constant current circuit with an
external voltage
5.3 Redundancy operation
By choosing option -O, ORing MOSFET is implemented into the unit.
Therefore, it is possible to connect each output directly for N + 1
redundancy operation.
See section 7.2.
5.4 Output current monitor
The output current can be monitored by measuring the voltage
between the CB and -S terminal.
Fig. 5.10 shows the relationship between the voltage of CB terminal
and the output current.
The output current shown in Fig. 5.10 is for reference only.
Output current monitor circuit example is shown in Fig. 5.11.
Fig. 5.10 CB terminal voltage vs output current
Fig. 5.11 Example of monitoring circuit
- Use a measuring instrument whose input impedance is 500kΩ or
higher
- Do not connect more than 0.01µF between the CB and -S terminal to
prevent output voltage malfunction.
- Wire carefully to avoid malfunction caused by noise.
- The pulse load cannot be monitored.
External potentiometer
OFD1200A
OFD1200A Load
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
VTRM
VTRM
Wire as close as possible
ITRM
ITRM
OFD1200A
OFD1200A Load
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
VTRM
VTRM
Vref
Wire as close as possible
External voltage source
ITRM
ITRM
0
3.25
0100
Voltage of CB terminal [V]
Load factor [%]
1.25
OFD1200A Load
+Vout
-Vout
-S
CB
5V
Signal out