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Cassette Style
100 Watt AC-DC (DC-DC) Converters
S Series
Edition 01/01.2001
20/25
E Inrush Current Limitation
The converters may be supplemented by an electronic cir-
cuit (option E, replacing the standard built-in NTC) to
achieve an enhanced inrush current limiting function.
Table 17: Inrush current characteristics with option E
Characteristics
LS
Unit
Ui = 230 V AC
typ
max
Iinr p
Peak inrush current
–
25.3
A
tinr
Inrush current duration
35
50
ms
Input
Filter
Control
Converter
FET
Ci
RI
RS
Rectifier
PFC
-
Control
1
1001
Fig. 27
Option E block diagram
Fig. 30
Paralleling of single output units using option T with the
sense lines connected at the load
1 Leads should have equal length and cross sections and should
run in the same cable loom.
2 Diodes recommended in redundant operation only
3 DC common point
Precaution: Subsequent switch-on cycles at start-up
are limited to max. 10 cycles during the rst 20 seconds
(cold unit) and at continuing on/off (
TC =95°C) max. 1
cycle every 8 sec.
Vo+
Vo–
Vo+
Vo–
Load
Vo+
Vo–
11003
T Current Sharing
This option ensures that the output currents are approxi-
mately shared between all paralleled modules and in-
creases system reliability. To use this facility, simply inter-
connect the T pins of all modules and make sure, that
pins 14, the S– pin (LS 1000) or the Vo1– pins (LS 2000)
are also connected together. The load leads should have
equal length and cross section to ensure equal voltage
drops. Not more than 5 units should be connected in paral-
lel. If output voltage adjustment is requested we strongly
recommend to use the R-input instead of option P, as with
Fig. 29
An example of poor wiring for connection in parallel
15
Ii [A]
10
5
0
–5
–10
–15
0
20
40
60
80
t [ms]
tinr
LS type
Ui = 230 V AC
Po = Po nom
Capacitor Ci
fully charged
Normal operation
(FET fully conducting)
20
10059
Fig. 28
Inrush current with option E
Load
1
2
3
LS 1000
S+
Vo+
Vo–
S–
N
P
T
LS 1000
N
P
S+
Vo+
Vo–
S–
T
1
max. 5 units connected in parallel
11041
Load
max. 5 units in parallel connection
+
–
Power bus
Module
Vo2–
Vo2+
Vo1–
Vo1+
T
Module
Vo2–
Vo2+
Vo1–
Vo1+
T
11037
Fig. 31
Paralleling of double output units using option T with
power bus.
option P the required setting accuracy is difcult to achieve.
The output voltages must be individually set prior to paral-
leling to within a tolerance of 1...2% or the R pins should be
connected together.