SSI
ERP2U Power Supply Design Guide, V2.31
- 29 -
STATUS
Required
The power supply over voltage protection shall be locally sensed in the hot swap modules. 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. Table 29 contains the over voltage limits. The values are
measured at the output of the power supply’s connectors. The voltage shall never exceed the maximum levels
when measured at the power pins of the power supply connector during any single point of fail. The voltage shall
never trip any lower than the minimum levels when measured at the power pins of the power supply connector.
Table 28: Over Voltage Limits
Output Voltage MIN (V) MAX (V)
+3.3 V 3.9 4.5
+5 V 5.7 6.5
+12V1,+12V2, +12V3, +12V4 13.3 14.5
-12 V -13.3 -14.5
+5 VSB 5.7 6.5
7.4 Over Temperature Protection STATUS
Recommended
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. The OTP circuit
must have built in hysteresis such that the power supply will not oscillate on and off due to temperature recovering
condition. The OTP trip level shall have a minimum of 4 °C of ambient temperature hysteresis.