Data Sheet

CPS20.241-60
C-Series
24V, 400W, DC/DC CONVERTER
23. APPLICATION NOTES
23.1. PEAK CURRENT CAPABILITY
The DC/DC converter can deliver peak currents (up to several milliseconds) which are higher than the specified short
term currents. This helps to start current demanding loads. Solenoids, contactors and pneumatic modules often have a
steady state coil and a pick-up coil. The inrush current demand of the pick-up coil is several times higher than the
steady-state current and usually exceeds the nominal output current. The same situation applies when starting a
capacitive load.
The peak current capability also ensures the safe operation of subsequent circuit breakers of load circuits. The load
branches are often individually protected with circuit breakers or fuses. In case of a short or an overload in one branch
circuit, the fuse or circuit breaker need a certain amount of over-current to open in a timely manner. This avoids
voltage loss in adjacent circuits.
The extra current (peak current) is supplied by the built-in large sized output capacitors of the DC/DC converter. The
capacitors get discharged during such an event, which causes a voltage dip on the output. The following two examples
show typical voltage dips:
Fig. 23-1 Peak load with 2x the nominal
current for 50ms, typ.
Fig. 23-2 Peak load with 5x the nominal
current for 5ms, typ.
10ms/DIV
Output
Voltage
Output
Current
24V
0A
32.6A
17V
1ms/DIV
Output
Voltage
Output
Current
24V
0A
81.5A
9V
32.6A Peak load (resistive) for 50ms
Output voltage dips from 24.5V to 17V.
81.5A Peak load (resistive) for 5ms
Output voltage dips from 24.5V to 9V.
Peak current voltage dips typ. from 24.5V to 17V at 32.6A for 50ms, resistive load
typ. from 24.5V to 18V at 81.5A for 2ms, resistive load
typ. from 24.5V to 9V at 81.5A for 5ms, resistive load
23.2. INDUCTIVE AND CAPACITIVE LOADS
The unit is designed to supply any kind of loads, including capacitive and inductive loads. If extreme large capacitors,
such as EDLCs (electric double layer capacitors or “UltraCaps”) with a capacitance > 0.5F are connected to the output,
the unit might charge the capacitor in the Hiccup
PLUS
-mode (see chapter 6).
Aug. 2016 / Rev. 1.0 DS-CPS20.241-60-EN
All parameters are specified at 24.5V, 16.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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