Clst (Closed Loop System Throttle) Definition - QUANTA W Mainboard Series S210-MBT2W Technical Manual

A S
BOUT THE ERVER
[1.3.253] With SmaRT the load the power supply must support
during an AC loss event can be reduced. A fast AC loss detec-
tion circuit inside the power supply asserts SMB_ALERT_N
when the AC input voltage is too low. The SMB_ALERT_N sig-
nal is used to initiate a throttle condition in the system. This
guarantees lighter loads on the power supply during an AC
dropout event. This can be used in the power supply design to
help in one of three different ways described below. Only one
of these options can be used in any given power supply design.
[1.3.254] SmaRT User Models
Improve the efficiency of the power supply by keeping the

bulk capacitor the same size and reducing the transformer
turns ratio of the output stage converter.
Reduce the size and cost of the power supply's bulk

capacitor.
Lengthen the system's AC dropout ride thru duration.

[1.3.255] CLST (Closed Loop System
Throttle) Definition
[1.3.256] Power supply ratings are sized conservatively to han-
dle worse case loading conditions on the system; not necessar-
ily typical loading conditions that the system actually sees in
their real use. In typical cases the power supply may never see
more than 40-60% continuous load. When higher loads are
present, it is only for a short duration until the work is com-
pleted. And in redundant power supplies the full un-throttled
system power is supported when there is a power supply fail-
ure. These standard power supply over-sizing reasons are in
place because there is no protection against a system failing
due to an improperly sized power supply; therefore, all power
supplies today are designed with some amount of rating margin
relative to the typical user.
[1.3.257] With CLST the rating of the power supply can be
sized more aggressively and more appropriately for the actual
system usage condition. A lower rated power supply will
reduce the cost and size of the power supply as well as lower
the system's power draw. CLST makes use of the
SMB_ALERT_N signal (same as SmaRT) to reduce system
power when and over energy condition or over temperature
condition exists in the power supply.
[1.3.258] CLST user models
Protection mechanisms to allow optimization of the power

supply's electrical design aspects for the real system oper-
ating conditions. This includes both peak and continuous
ratings.
Protection mechanism to allow optimizing the power sup-

ply's thermal design based on its operating state. This
includes the system's ambient temperature and continu-
ous loading condition.
Protection mechanism to allow reducing the rating of

redundant power supplies. During a power supply failure
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AC P S (
OWER UPPLIES TO BE UPDATED
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