Kontron CP383 - Manual (Page 68)

Power Consumption CP383
Page 5 - 4 © 2004 Kontron Modular Computers GmbH ID 27784, Rev. 01
5.1.2 Backplane
The backplane to be used with the CP383 must be adequately specified and must provide op-
timal power distribution for the +3.3 V power input.
5.1.3 Power Supply Units
The start-up behavior of CPCI and PCI (ATX) power supplies is critical for all new CPU boards.
These boards require a defined power of sequence and start-up behavior of the power supply.
The required behavior is described in the ATX (
http://www.formfactors.org/FFDe-
tail.asp?FFID=1&CatID=2 ) and the CPCI (PICMG, http://www.picmgeu.org/ ) specification.
5.1.3.1 Start-Up Requirement
Power supplies must comply with the following in order to be used with the CP383.
• Beginning at 10% of the nominal output voltage, the voltage must rise within > 0.1 ms to
< 20 ms to the specified regulation range of the voltage. Typically: > 5 ms to < 15 ms.
• There must be a smooth and continuous ramp of each DC output voltage from 10% to
90% of the regulation 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.
The following figure illustrates an example of the recommended start-up ramp of a CPCI power
supply for all Kontron boards delivered up to now.
Figure 5-1: Start-Up Ramp of the CP3-SVE180 AC Power Supply
5.1.3.2 Power-up Sequence
The +5 VDC output levels must always be equal to or higher than the +3.3 VDC output during
power-up and normal operation.
The time from +5 VDC until the output reaches its minimum in regulation level and from
+3.3 VDC until the output reaches its minimum in regulation level must be < 20 ms.