Product guide

QSSC-S4R Server System Product Guide Chapter 1: System Description

Version 1.0

Power Distribution Board

The power distribution board is located below the main board in the chassis. It has four connectors for hot swap

power supply modules. It also contains the control logic supporting the cold redundancy feature, along with

240VA additional protection circuitry for one of the outputs and a FRU EEPROM. It also routes PMBus I²C

signals from the power supply modules to the system baseboard and vice versa.

The S4R PDB supports the following features:

 Four power supply card edge gold fingers – the power supply unit (PSU) hot docks to the PDB with mating

connectors on the PSU side and gold fingers along the PDB edge

 Cold redundancy functionality.

 Cold redundancy enabled (default setting): jumper short located on #2 and #3.

 Cold redundancy disabled: jumper short located on #1 and #2.

 Passes signals to baseboard PLD for power utilization functionality for processor/memory throttling when

supporting high power hardware configurations with less than three functional power supplies installed.

 FRU EEPROM

 240VA limit circuit for 12V power to operator accessible areas on Hot-Swap Backplane (HSBP) and HDDs

 The +12V output power requirements from the power distribution board for one to four 850W power supplies

installed and functional. Note: the combined continuous total power limit for all outputs is 2300W maximum

 Utilization logic on the PDB incorporates 4 comparators receiving 4 reference voltages and comparing them

with the current share bus signal. The comparators generate four utilization active low logic signals pulled up

to the 3.3VSB output. The signals are asserted when power (current) per power supply exceeds 70%, 80%,

90% and 95% of the rated (max current share bus signal) level.

Item Description

A Power supply edge connection: PSU#1

B Power supply edge connection: PSU#2

C Power supply edge connection: PSU#3

D Power supply edge connection: PSU#4

E 2X5 Pin PCIe / Chipset

F 2X8 pin BMI Connector

G Cold Redundancy Jumper

H 2X4 pin HSBP/Fan Power

I 2X2 pin CPU/DIMM power

J 2X8 pin CPU/DIMM power

K 2X17 pin power control land pattern, uses 2X13

connector

L 2X8 pin CPU/DIMM power

Figure 28. Power Distribution Board Connectors