User manual

CD5.241, CD5.241-S1
CD–Series
DC/DC Converter; 24V, 5A
Jan. 08 / Rev. 1.1 DS-CD5.241-EN / All parameters are specified at 24V, 5A and 24Vdc input at 25°C ambient unless otherwise noted.
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6. SOFT-START AND INPUT INRUSH CURRENT SURGE
Inrush current limitation
An active inrush limitation circuit (inrush limiting resistor which is bypassed by a relay contact) limits the input inrush
current after turn-on of the input voltage.
The charging current into EMI suppression capacitors is disregarded in the first microseconds after switch-on.
Input 24Vdc
Inrush current
max. 1.6A
peak
-25°C to +70°C
typ. 1.2A
peak
-25°C to +70°C
Inrush energy
typ. negligible -25°C to +70°C
Fig. 6-1 Input inrush current, typical behavior
Input Current
Input Voltage
Output Voltage
Input: 24Vdc
Output: 24Vdc, 5A, constant current load
Ambient: 25°C
Upper curve: Input current 2A / DIV
Middle curve: Input voltage 20V / DIV
Lower curve: Output voltage 20V / DIV
Time scale: 100ms / DIV
Soft-start function:
After the DC/DC converter is turned on, the internal output current rises slowly to its nominal value. This method
charges the output capacitors (internal and external capacitors) slowly and avoids high input currents during turn-on.
High input currents can produce a high voltage drop on the input wiring (especially with long and thin cables) which
reduces the terminal voltage on the DC/DC converter. If the terminal voltage is below the shut-down voltage, the
DC/DC converter will turn-off and will make a new start-up attempt. This effect is avoided with the integrated soft-
start function. Please note, that this function increases the rise time of the output voltage by a small amount.
Fig. 6-2 Soft-start behavior
Input Current
Output Voltage
Input: 24Vdc
Output: 24Vdc, 5A, constant current load
Ambient: 25°C
No additional external capacitors
Upper curve: Input current 2A / DIV
Lower curve: Output voltage 10V / DIV
Time scale: 20ms / DIV