Power Considerations
CP932
Page 5 - 6
© 2005 Kontron Modular Computers GmbH
ID 30048, Rev. 01
3004
8.01.UG.VC.050622/19130
1
P R E L I M I N A R Y
5.4.4
Recommended Operating Conditions
The tolerance of the voltage lines is described in the CompactPCI specification (PICMG 2.0
R3.0).The recommended measurement point for the voltage is the CompactPCI connector on
the CP932.
The output voltage overshoot generated during the application (load changes) or during the
removal of the input voltage must be less than 5% of the nominal value. No voltage of reverse
polarity may be present on any output during turn-on or turn-off.
The following table provides information regarding the required characteristics for each board
input voltage.
5.4.5
Supply Voltage Regulation
The power supply shall be unconditionally stable under line, load, unload and transient load
conditions including capacitive loads. The operation of the power supply must be consistent
even without the minimum load on all output lines.
Table 5-3: Input Voltage Characteristics
VOLTAGE
NOMINAL VALUE
TOLERANCE
MAX. RIPPLE (p-p)
5 V
+5.0 VDC
+5%/-3%
50 mV
V I/O
(PCI signaling voltage)
+3.3 VDC or +5 VDC
+5%/-3%
50 mV
GND
Ground, not directly connected to protective earth (PE)
Note ...
Non-industrial ATX PSUs require a greater minimum load than a single CP932
is capable of creating. When a PSU of this type is used, it will not power up
correctly and the CP932 may hang up. The solution is to use an industrial PSU
or to add more load to the system.
Note ...
If the main power input is switched off, the supply voltages will not go to 0V
instantly. It will take a couple of seconds until capacitors are discharged. If the
voltage rises again before it has gone below a certain level, the circuits may
enter a latch-up state where even a hard RESET will not help any more. The
system must be switched off for at least 3 seconds before it may be switched
on again. If problems still occur, turn off the main power for 30 seconds before
turning it on again.
