Kontron VMP3 - Manual (Page 131)

VMP3 System Considerations
ID 29230, Rev. 01 © 2005 Kontron Modular Computers GmbH Page 6 - 7
30504
.01.VC.050727/091441
P R E L I M I N A R Y
6.3.4.1 Voltage Ramp
Power supplies must comply with the following guidelines, in order to be used with the VMP3.
• 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.
6.3.4.2 Recommended Operating Conditions
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 the input
voltage.
6.3.4.3 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.
6.3.5 Power Consumption of the VMP3
The goal of this description is to provide a method to calculate the power consumption for the
VMP3 board and for additional configurations. The MPC8541E processor, the Gigabit Ethernet,
and the DDR SDRAM dissipate the majority of the thermal power.
The power consumption tables below list the voltage and power specifications for the VMP3
PHYs. The software used for this test was the ECOS based NetBootLoader without any power
management features being enabled during the measurement. All measurements were con-
ducted at a temperature of 25°C.
Table 6-4: Input Voltage Characteristics
VOLTAGE NOMINAL VALUE TOLERANCE MAX. RIPPLE (p-p)
+5 V +5 VDC +5%/-3% 50 mV
GND Ground, not directly connected to protective earth (PE)
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.