Datasheet
CD5.243
CD-Series 
DC/DC Converter 24V, 4A 
Peak current capability (up to several milliseconds) 
The DC/DC converter can deliver a peak current, which is higher than the specified short term current. This helps to 
start current demanding loads or to safely operate subsequent circuit breakers. 
The extra current is supplied by the output capacitors inside the DC/DC converter. During this event, the capacitors will 
be discharged and causes a voltage dip on the output. Detailed curves can be found in chapter 21.1. 
Peak current voltage dips  typ.  from 24V to 18V  at 8A for 50ms, resistive load 
  typ.  from 24V to 12.5V  at 16A for 2ms, resistive load 
  typ.  from 24V to 10V  at 16A for 5ms, resistive load 
6.  HOLD-UP TIME 
The input side of the DC/DC converter is equipped with a bulk capacitor which keeps the output voltage alive for a 
certain period of time when the input voltage dips or is removed. The bulk capacitor can be discharged by loading the 
DC/DC converter on the output side or through a load which is parallel to the input. There is no protection in the 
DC/DC converter which prevents current from flowing back to the input terminals. If prevention is needed, an external 
diode should be used. 
Hold-up Time  typ.  5.8ms  input 12Vdc, output: 24Vdc, 2A, see Fig. 6-1
  typ.  3.0ms  input 12Vdc, output: 24Vdc, 4A, see Fig. 6-1 
  Fig. 6-1 Hold-up time vs. input voltage     
0
1
2
3
4
6ms
9101112 14Vdc
Input Voltage
Hold-up Time
(a) 24V, 2A, typ.
(b) 24V, 2A, min.
(c) 24V, 4A, typ.
(d) 24V, 4A, min.
5
13
(
a
)
(
b
)
(
c
)
(
d
)
  Fig. 6-2 Shut-down test setup    Fig. 6-3 Shut-down behavior, definitions 
Load
+
-
DC/DC
Converter
DC
Source
+
-
Input
Output
+
-
CD5
S1
- 10%
Hold-up Time
Output
Voltage
Intput
Voltage
S1 opens
Note: At no load, the hold-up time can be up to several seconds. The green DC-ok lamp is also on during this time. 
Mar. 2016 / Rev. 1.3 DS-CD5.243-EN 
All parameters are specified at 24V, 4A, 12Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted. 
www.pulspower.com Phone +49 89 9278 0 Germany 
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