Protection Circuits; Current Limit (Ocp); Over Voltage Protection (Ovp); Over Temperature Protection (Otp) - Intel SC5275-E Technical Product Specification

Appendix A: Chassis Spares and Accessories
3.3

Protection Circuits

Protection circuits inside the power supply shall cause only the power supply's main outputs to
shutdown. If the power supply latches off due to a protection circuit tripping, an AC cycle OFF
for 15sec and a PSON
3.4

Current Limit (OCP)

The power supply shall have current limit to prevent the +3.3V, +5V, and +12V outputs from
exceeding the values shown in Table 23. If the current limits are exceeded the power supply
shall shutdown and latch off. The latch will be cleared by toggling the PSON
AC power interruption. The power supply shall not be damaged from repeated power cycling in
this condition. -12V and 5VSB shall be protected under over current or shorted conditions so
that no damage can occur to the power supply. 5Vsb will be auto-recovered after removing OCP
limit.
3.5

Over Voltage Protection (OVP)

The power supply over voltage protection shall be locally sensed. The power supply shall
shutdown and latch off after an over voltage condition occurs. This latch shall be cleared by
#
toggling the PSON signal or by an AC power interruption.
3.6

Over Temperature Protection (OTP)

The power supply will be protected against over temperature conditions caused by loss of fan
cooling or excessive ambient temperature. In an OTP condition the PSU will shutdown. When
the power supply temperature drops to within specified limits, the power supply shall restore
power automatically, while the 5VSB remains always on.
3.7

Control and Indicator Functions

The following sections define the input and output signals from the power supply.
Signals that can be defined as low true use the following convention:
#
Signal = low true
3.8

PSON# Input Signal

#
The PSON signal is required to remotely turn on/off the power supply. PSON
signal that turns on the +3.3V, +5V, +12V, and -12V power rails. When this signal is not pulled
low by the system, or left open, the outputs (except the +5VSB) turn off. This signal is pulled to
a standby voltage by a pull-up resistor internal to the power supply
3.9

PWOK (Power OK) Output Signal

PWOK is a power OK signal and will be pulled HIGH by the power supply to indicate that all the
outputs are within the regulation limits of the power supply. When any output voltage falls below
regulation limits or when AC power has been removed for a time sufficiently long so that power
supply operation is no longer guaranteed, PWOK will be de-asserted to a LOW state.
3.9.1

Mean Time Between Failures (MTBF)

The power supply shall have a minimum MTBF at continuous operation of 100,000 hours at
80% load at 40°C, as calculated by the Bellcore* RPP, or 250,000 hours demonstrated at 80%
°
load at 40 C.
20
#
cycle HIGH for 1sec shall be able to reset the power supply.
Intel® Server Chassis SC5275-E TPS
#
signal or by an
#
is an active low
Revision 1.2