page
date
7 of 9
04/2008
PART NUMBER:
VHK50W
DESCRIPTION:
chassis mount dc-dc converter
10. OUTPUT OCP AND SHORT-CIRCUIT PROTECTION
Output overload and short circuit conditional will cause the output voltage to decline or shutdown altogether.
If the case temperature
is not over 85°C, the output recovers automatically when the short or OCP conditions are removed. In the case of slight overloading,
the output voltage may not shut down, but the converter may build up heat over time, causing over-temperature shutdown.
11. OVER-TEMPERATURE PROTECTION
When the case temperature reaches about 85°C, the converter's built-in protection circuit will shut down the output. When the tem-
perature is reduced enough to a safe operating level, the converter will recover to normal operations automatically.
12. OUTPUT OVP
In case the output voltage exceeds the OVP threshold, the converter shuts down.
13. OUTPUT PARALLEL CONNECTIONS
The converter is not designed for load share on the output. However, for redundancy, the outputs of two or more converters can be
connected in parallel through O-Ring diodes, as shown below.
+Vin
+Vo
-Vin
FIGURE 6. OUTPUT
PARALLEL CONNECTIONS
+Vin
-Vo
+Vo
-Vin
-Vo
14. OUTPUT SERIES CONNECTIONS
Two or more converters can be connected in series to obtain a higher output voltage. To prevent output reverse biasing each other in
case of a short, add a Schottky diode on each output in reverse polarity, as shown in the diagram. In the event of a short, the con-
verters will forward-bias the diodes and the output reversal will be limited to one diode drop (about 0.5V) only, so as not to damage
the converters. The forward current will cause each converter to go into short-circuit protection.
For proper diode selection, make
sure that: 1) the diodes voltage rating is higher than each converter output; 2) the rated diode current can carry the short-circuit cur-
rent; 3) the diodes do not overheat before the short is removed.
+Vin
+Vo
-Vin
FIGURE 7. OUTPUT
SERIES CONNECTIONS
+Vin
-Vo
+Vo
-Vin
-Vo
20050
SW
112
th
Ave. Tualatin, Oregon
97062
phone
503.612.2300
fax
503.612.2382
CUI [ CUI INC ]
