PAF600F280-28 TDK Corporation, PAF600F280-28 Datasheet - Page 39

• Manufacturer Part Number: PAF600F280-28
• Description: 28V@21.5A
• Manufacturer: TDK Corporation

・All specifications are subject to change without notice.
PAF
When using the remote sensing function, output voltage
at the output terminals of the power module generally be-
comes higher than the voltage at the load input terminals.
OVP circuit monitors output voltage from the output termi-
nals. Therefore, for cases where remote sensing function
is used together, consider voltage drop from the power
module output terminals to the load input terminals when
setting OVP value.
Output voltage of the power module excessively changes
when output load or input voltage abruptly change. For this
case, set enough margins for output voltage peak when
setting OVP value.
Be sure to verify beforehand that OVP does not falsely
trigger at actual evaluation for worst output load or input
voltage conditions
9 Over Thermal Protection
This power module has built-in OTP function. This function
operates and shuts down the output when ambient temper-
ature or internal temperature of power module abnormally
rises. OTP operates at 95℃ to 115℃ baseplate tempera-
ture.
Output can be recovered by turning input line off and then
turning it on again after temperature sufficiently decreased.
 Remote Sensing (+S, -S terminal)
Remote sensing terminal is provided to compensate for
voltage drop across the wiring from the power module out-
put terminal to the load’ s input terminal.
When remote sensing function is not used (local sensing),
short +S terminal to +V terminal and, -S terminal to –V ter-
minal
Take note that voltage compensation range for line drop
(voltage drop due to wiring) should be kept such that out-
put voltage at the output terminals is within output voltage
range, and voltage between –V and –S terminals is within
2V or less. And the maximum power is not exceeded. Use
shielded wire, twist pair, or parallel pattern to reduce noise
effect.
Also take care of the inductance of the line load. Maintain
total inductance value under 200nH.
When this value is exceeded, characteristics of power
module might be unstable.
400F280
Fig.10-2 Remote Sensing Not in Use
Fig.10-1 Remote Sensing in Use
＋S
＋V
−V
−S
＋S
＋V
−V
−S
Stabilize the output voltage at
load terminal
+
+
Stabilize the output voltage at
Output terminal
Twisted
(example)
+
Load
Load
＋
−
＋
−
 ON/OFF Control (CNT, SG terminal)
Without turning the input supply on and off, the output can
be enabled and disabled using this function.
ON/OFF control circuit is on the input side (the primary
side), CNT terminal. Use the SG terminal as ground for
CNT terminal.
If this function is not used, short the CNT terminal and the
SG terminal.
1）The maximum allowable applied voltage for the CNT
2）ON/OFF terminal can be controlled by opening or closing
*When using photo-coupler, connect between the CNT and
 Parallel Operation (PC terminal)
By connecting the PC terminal of each power module and
adding the external circuit, output current can be equally
drawn from each module. A maximum of 20 units of the
same model can be connected.
Be sure that the output power of every module does not
exceed the maximum output power value.
By setting output voltage accuracy of each module in
a parallel operation to within ±1 % , the maximum value
of the output current can be drawn in the rated output
current..
Refer to “Parallel Operation” of the PAF400F280 series
Application Notes for details.
 Series Operation
Series operation is possible for PAF400F280 series.
Connections shown Fig.13-1and Fig.13-2 is possible.
the SG terminal to make transistor side shortest.
terminal is 35V and the maximum reverse voltage
value is 0.7V. Also the source current for CNT terminal
is about 0.1mA.
When wiring becomes long, connect a capacitor about
0.1µF value between the CNT and the SG terminal at
a nearest distance.
connections (with switch or relay), or by photo-coupler
ON/OFF.
Also for the secondary control, isolation can be
achieved through the use of a photo-coupler or
equivalent.
Fig.13-1 Series Operation for High Output Voltage
Ｈ (4V and above ) or Open
Ｌ (0.8V and below )or short
Fig.11-1 CNT, SG terminal connection
＋S
＋V
−V
−S
＋S
＋V
−V
−S
Table 11-1 ON/OFF Control Mode
Application
CNT Level
+
+
Fuse
C1
＋
＋Vin
−Vin
SG
CNT
Output Status
Load
＋
−
OFF
ON
B-131
PAF