Intel® Server Board SE7520JR2

Design and Environmental Specifications

8.2.11Soft Starting

The power supply shall contain control circuit that provides monotonic soft start for its outputs without overstress of the AC line or any power supply components at any specified AC line or load conditions. There is no requirement for rise time on the 5V Standby but the turn on/off shall be monotonic.

8.2.12Zero Load Stability Requirements

When the power subsystem operates in a no load condition, it does not need to meet the output regulation specification, but it must operate without any tripping of over-voltage or other fault circuitry. When the power subsystem is subsequently loaded, it must begin to regulate and source current without fault. Each output voltage may not be internally diode isolated. At the same time failure in the primary side of one power supply doesn’t cause the other to shut down.

8.2.13Timing Requirements

These are the timing requirements for the power supply operation. The output voltages must

rise from 10% to within regulation limits (Tvout_rise) within 5 to 70ms, except for 5VSB - it is allowed to rise from 1.0 to 70ms. The +3.3V, +5V and +12V output voltages should start to rise

approximately at the same time. All outputs must rise monotonically. The +5V output needs to be greater than the +3.3V output during any point of the voltage rise. The +5V output must never be greater than the +3.3V output by more than 2.25V. Each output voltage shall reach

regulation within 50ms (Tvout_on) of each other during turn on of the power supply. Each output voltage shall fall out of regulation within 400msec (Tvout_off) of each other during turn off. The following figures show the timing requirements for the power supply being turned on and off via

the AC input, with PSON held low and the PSON signal, with the AC input applied.

Table 122: Output Voltage Timing

Item

Description

Minimum

Maximum

Units

Tvout_rise

Output voltage rise time from each main output.

5.0 *

70 *

msec

Tvout_on

All main outputs must be within regulation of each

 

50

msec

 

other within this time.

 

 

 

T vout_off

All main outputs must leave regulation within this

 

400

msec

 

time.

 

 

 

Note:

 

 

 

 

The 5VSB output voltage rise time shall be from 1.0ms to 25.0ms

 

 

 

Revision 1.0

209

 

C78844-002