3 Watt-Family
DC-DC Converters <40 W
Rugged Environment
6 - 14
Edition 2/96 - Melcher AG
MELCHER
The Power Partners.
6.1
Installation Instructions
Isolation Tests
Input to output isolation voltage tests are performed as factory tests (100 %) and should not be repeated in the field.
Melcher will not honour any guarantee/warranty claims resulting from high voltage field tests.
Table 8: Isolation test voltage, coupling capacitance and insulation resistance
Characteristics
Conditions
IPS
IPW 1
Unit
Uis io
Isolation test voltage
AC: 50 Hz,
500
1060
Vrms
Input to output
1 minute
1400
3000
Vpp
DC: 1 second 2
700
1500
V
DC: 1 second 3
800
1700
Uis oo
Isolation test voltage
AC: 50 Hz,
500
1060
Vrms
output to output 4
1 minute
1400
3000
Vpp
DC: 1 second 2
700
1500
V
DC: 1 second 3
800
1700
Cio
Coupling capacitance
typ
300
external 5
pF
Ris
Insulation resistance
at 100 V DC
≥2000
M
after 1 minute
1 According to EN 41003 (1993)
2 For production test purposes in accordance with IEC 950/EN 60950
3 Factory test procedure
4 Group 03
5 Important: All IPW types need (an) external coupling capacitor(s) Cio of min. 220 pF, 1 kVrms
Connection in Series
If the outputs of one or more units are connected in series
each individual output should be protected by a zener diode
or preferably by a suppressor diode to avoid overvoltages
or reverse polarity at the individual outputs, e.g.: 1N5908
(5 V), BZW04-11 (12 V), BZW04-14 (15 V) or equivalent
types.
Such destructive voltages may occur at switch-on cycle of
the converters, if the output voltages do not rise at the same
time. The "slower" output(s) could be supplied and, as a
result, destroyed by the "faster" output(s) via the load. The
maximum output current is limited by the lowest current
limitation.
Connection in Parallel
Connection of the outputs of one or more units in parallel is
not permitted. The load distribution and the ripple values
could not be controlled.
Cleaning
Two CFC free cleaning solvents have been tested and can
be recommended:
– Prozone from BP
– Zestron from Dr. O. K. Wack Chemie GmbH (Germany)
Submersion of the units in water for rinsing is permitted.
Drying should be done in the air.
Unit 1
Unit 2
+
Uo
–
Uo
+Vo
Go
–Vo
+Vo
Go
–Vo
Fig. 1
Outputs connected in series
Shutdown Description
The shutdown terminal is used to switch the converter out-
put voltage
Uo on and off via a control signal (e.g. using an
open collector drive). See "Electrical Input and Output
Data".
The output voltage is switched on when the shutdown ter-
minal is open circuit or +8...+10 V. The output voltage is
switched off when a voltage of –0.3...+2 V is applied to the
shutdown terminal. At the open shutdown pin 10...12 V will
appear.