Rugged Environment
DC-DC Converters >100 W
K-Family
Edition 2/96 - Melcher AG
8 - 21
MELCHER
The Power Partners.
8.1
Fig. 22
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
Load
1
2
3
Module
S+
Vo+
Vo–
S–
Vi+/N
Vi–/P
T
Module
Vi+/N
Vi–/P
S+
Vo+
Vo–
S–
T
1
max. 5 units in parallel connection
Option D Undervoltage monitor
The input and/or output undervoltage monitoring circuit op-
erates independently of the built-in input undervoltage lock-
out circuit. A logic "low" (JFET output) or "high" signal (NPN
output) is generated at pin 20 as soon as one of the moni-
tored voltages drops below the preselected threshold level
Ut. The return for this signal is Vo1–. The D output recovers
when the monitored voltage(s) exceed(s)
Ut + Uh. The
Load
max. 5 units in parallel connection
+–
Power bus
Module
Vo2+
Vo1+
Vo2–
Vo1–
Vi+/N
Vi–/P
T
Module
Vi+/N
Vi–/P
Vo2+
Vo1+
Vo2–
Vo1–
T
Fig. 23
Paralleling of double output units using option T
threshold levels
Uti and Uto are either adjustable by a
potentiometer, accessible through a hole in the front cover,
or factory adjusted to a fixed value specified by the cus-
tomer.
Option D exists in various versions D0...DD as shown in the
following table.
Table 15: Undervoltage monitor functions
Output type
Monitoring
Minimum adjustment range
Typical hysteresis
Uh [% of Ut]
JFET
NPN
U i
Uo1
of threshold level
U t
for
U t min...U t max
Uti
Uto
Uhi
Uho
D1
D5
no
yes
-
-
2.5...0.6
D2
D6
yes
no
Ui min...Ui max 1
-
3.4...0.4
-
D3
D7
yes
Ui min...Ui max 1
(0.95...0.985
Uo1) 2
3.4...0.4
"0"
D4
D8
no
yes
-
(0.95...0.985
Uo1) 2
-
"0"
D0
D9
no
yes
-
3.5...40 V 3
-
2.5...0.6
yes
no
Ui min...Ui max 3 4
-
3.4...0.4
-
yes
Ui min...Ui max 3 4
3.5...40 V 3
3.4...0.4
2.5...0.6
yes
Ui min...Ui max 3 4
(0.95...0.985
Uo1) 2
3.4...0.4
"0"
-
DD
yes
Ui min...Ui max 1
3.5...40 V 1
3.4...0.4
2.5...0.6
1 Threshold level adjustable by potentiometer
2 Fixed value tracking if Uo1 is adjusted via R-input, option P or sense lines.
3 The threshold level permanently adjusted according to customer specification
±2 % at 25°C. Any value within the specified range is
basically possible but causes a special type designation in addition to the standard option designations (D0/D9 respectively)!
4 Adjusted at Io nom