Specifications
Power Distribution Board (PDB) QSSC-S4R Technical Product Specification
110
Figure 55. Power Supply Numbering on the PDB
The QSSC-S4R PDB supports the following features:
x Board size: 15.35” (390mm) x 3.31” (84mm)
x Tool-less attached
x 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, as shown in Figure 55. Power Supply
Numbering on the PDB.
x Cold redundancy functionality
x 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.
x FRU EEPROM
x 240VA limit circuit for 12V power to operator accessible areas on Hot-Swap Backplane (HSBP) and HDDs
x 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
x Utilization logic on the PDB incorporates 4 comparators receiving 4 reference voltages and comparing them with
the current share bus signal. The comparators will be generating four utilization active low logic signals pulled up to
the 3.3VSB output. The signals will be asserted when power (current) per power supply exceeds 70%, 80%, 90%
and 95% of the rated (max current share bus signal) level.
13.2 Functional Block Diagram and Feature Description
The figure below shows the functional block diagram of the power distribution board. The control logic always enables
at least one power supply module once system PS_ON (PS_Enable) signal is generated. The number of enabled
modules depends on the power consumed by the system and active modules status. The PDB monitors output power
level via PMBus or current share bus (optional) and enables power supplies 2, 3, 4, based on a condition that
maximum power subsystem efficiency would be guaranteed at any given power level.