Power Supply Units - Kontron CP6930 User Manual

6.1.3 Power Supply Units

Power supplies for the CP6930 must be specified with enough reserve for the remaining system consump-
tion. In order to guarantee a stable functionality of the system, it is recommended to provide more power
than the system requires. An industrial power supply unit should be able to provide at least twice as much
power as the entire system requires. An ATX power supply unit should be able to provide at least three times
as much power as the entire system requires.
As the design of the CP6930 has been optimized for minimal power consumption, the power supply unit shall
be stable even without minimum load.
Where possible, power supplies which support voltage sensing should be used. Depending on the system
configuration this may require an appropriate backplane. The power supply should be sufficient to allow for
backplane input line resistance variations due to temperature changes, etc.
Note..
Non-industrial ATX PSUs require a greater minimum load than a single CP6930 is
capable of creating. When a PSU of this type is used, it will not power up correctly
and the CP6930 may hang up. The solution is to use an industrial PSU or to add
more load to the system.
6.1.3.1 Start-up Requirement
Power supplies must comply with the following guidelines, in order to be used with the CP6930:
• The input voltage shall rise at a rate of max. 1.5A per ms.
• There must be a smooth and continuous ramp of each DC output voltage from 10% to 90% of the regu-
lation band.
• The slope of the turn-on waveform shall be a positive, almost linear voltage increase and have a value
from 0 V to nominal Vout.
6.1.3.2 Power-up Sequence
The +5 VDC output level must always be equal to or higher than the +3.3 VDC output during power-up and
normal operation.
Both voltages must reach their minimum in-regulation level not later than 20 ms after the output power
ramp start.
74
Power Considerations
CP6930 User Guide
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