Cassette Style
DC-DC Converters
M Series
Edition 01/01.2001
20/25
Fig. 20
Typical inrush current waveforms of CM, CMZ, EM, LM
and LMZ DC-DC converter with option E
Precautions:
In order to avoid overload of the series resistor RI the on/off
switching cycle should be limited to 12 s if switched on/off
continuously. There should not be more than 10 start-up
cycles within 20 s at a case temperature of 25
°C.
If CM and CMZ types are driven by input voltages below
35 V DC or LM and LMZ types below 100 V AC, the maxi-
mum case temperature should be derated by 10 K or the to-
tal output power should be derated by 20%. EM, LM and
LMZ units driven by DC input voltages do not need to be
derated within the full specified input voltage range.
Availability:
Option E is available for CM, EM, LM and CMZ, LMZ mod-
ules with a nominal output power of 51 W maximum.
Input
Filter
Control
Converter
FET
Ci
RI
RS
Rectifier
(LM/LMZ types)
11018
Fig. 19
Option E block diagram
Table 19: Inrush current characteristics with option E
Characteristic
CM, CMZ
EM, LM, LMZ
Unit
at
Ui = 110 V DC
at
Ui = 110 V DC
at
Ui = 372 V DC
typ
max
typ
max
typ
max
Iinr p
Peak inrush current
6.5
8
2.2
4
7.3
10
A
tinr
Inrush current duration
22
30
10
20
40
ms
E Electronic Inrush Current Limitation
Available for CM, EM, LM and CMZ, LMZ types.
The standard version of the modules CM, DM, EM, LM as
well as CMZ, DMZ, LMZ include a passive inrush current
limitation in the form of a NTC resistor.
For applications which require an improved inrush current
limitation, an active electronic circuit as shown in fig.
Option
rent waveforms of units equipped with this option are
shown below.
CM and CMZ units meet the CEPT/ETSI standards for 48 V
DC supply voltage according to ETS 300132-2 if fitted with
option E combined with option D6 (input voltage monitor-
ing). Option D6, externally adjustable via potentiometer, is
necessary to disable the converter at input voltages below
the actual service ranges, avoiding an excessive input cur-
rent when the input voltage is raised slowly according to
ETS 300132-2. Option D6 threshold level
Uti + Uhi (refer to
description of option D) should be adjusted to 36.0...40.5 V
for 48 V DC nominal supply voltage (for 60 V DC systems,
threshold should be set to 44.0...50.0 V DC). The D output
(pin 5) should be connected to the inhibit (pin 2). For appli-
cations where potentiometers are not allowed refer to op-
tion D9.
12
10
8
6
4
2
0
10
20
30
40
t [ms]
Ii [A]
tinr
Normal operation
(FET fully conducting)
Ii = Po/(Ui η)
11019
tinr
CM, CMZ at 110 V DC
EM, LM, LMZ at 372 V DC
EM, LM, LMZ at 110 V DC
F Fuse Not Accessible
The standard M units have a fuseholder containing a 5
× 20
mm fuse which is externally accessible and to be found in
the back plate near the connector. Some applications re-
quire an inaccessible fuse. Option F provides a fuse moun-
ted directly onto the main PCB inside the case.
The full self-protecting functions of the module do normally
not lead to broken fuses, except as a result of inverse polar-
ity at the input of an AM, BM, CM, FM or CMZ type or if a
power component inside fails (switching transistor, free-
wheeling diode, etc). In such cases the defective unit has to
be returned to Power-One for repair.
H Enhanced Electric Strenght Test
Electric strength test voltage output to case 2800 V DC
(2000 V AC) instead of 1400 V DC (1000 V AC).