Specifications

Power Distribution Board (PDB) QSSC-S4R Technical Product Specification
116
1. PSAlert#_1
2. PSAlert#_2
3. PSAlert#_3
4. PSAlert#_4
5. PS1_OCP
6. PS2_OCP
7. PS3_OCP
8. PS4_OCP
13.2.10 PMBus Requirements
The PMBus features are limited to passing the I2C signals from the power supply modules to the system baseboard
and vice versa. The FRU data format (FRU EEPROM located on PDB) is compliant with the IPMI specifications.
13.3 Cold Redundant Operation
The power distribution board supports both hot-redundant (when all four power supplies are active all the time) and
cold-redundant operations (when only some of the power supplies are active and providing the required power to the
system, while the remaining supplies are set in a standby state).
13.3.1 PDB Cold Redundancy Control Circuitry
The PDB cold redundancy control circuitry monitors:
1. The active power supply states by examining:
a. PWOK status
b. AC in status
c. 12V local status
2. Total Output power usage
3. Output voltage level
The PDB cold redundancy control circuitry enables ALL standby power supply modules when:
1. At least one active module has failed;
2. AC line voltage coupled to at least one PS module goes out of specified range (or SMBalert# has been generated);
3. Total output power exceeds the level at which PS efficiency starts to drop due to IR losses.
4. A logic signal compatible with the PS_ON input of PS2, PS3, PS4 must be asserted indicating that this condition
has been reached
5. A pin on the PS output connector must be allocated for this signal
6. The signal generating circuit must incorporate hysteresis preventing it from oscillation under small 5%(TBD)
current variations
. PS status*
AC status CR status
4PSs present and OK All AC sources OK Enabled, PSs take turns (once a
week**) in becoming active
4PSs present and OK One or more AC sources not
OK
Disabled, all available PSs are
active
One or more PSs not OK All AC sources OK Disabled, all available PSs are
active
Less than 4PSs present and
OK
All associated AC sources OK Enabled, PSs take turns (once a
week**) in becoming active
Less than 4PSs present and
OK
One or more associated AC
sources not OK
Disabled, all available PSs are
active
One or more PSs not OK One or more AC sources not
OK
Disabled, all available PSs are
active
* PS status will be determined at each initial system start up (when all PSs are enabled)
** This time period may be TBD.