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| EPS2U Power Supply Design Guide, V2.1 | |
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| Table 26: Over Current Protection |
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| Common Plane | Split Plane |
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| Voltage | Over Current Limit (Iout limit) | Over Current Limit (Iout limit) |
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| +3.3 V | 110% minimum; 150% maximum | 110% minimum; 150% maximum | |
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| +5 V | 110% minimum; 150% maximum | 110% minimum; 150% maximum | |
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| +12V1 | 18A minimum; 20A maximum; 22A peak1 | 15A minimum; 20A maximum |
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| +12V2 | Peak current minimum; 20A maximum | Peak current minimum; 20A maximum | |
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| +12V3 | Peak current minimum; 20A maximum (550W only) | Peak current minimum; 20A maximum | |
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| +12V4 | N/A | Peak current minimum; 20A maximum | |
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1.+12V1 peak currents shall be maintained for a minimum of 500msec. The maximum duration of the peak current exceeding the 240VA limit should be limited to meet safety regulations. A maximum duration of 1 second is recommended.
7.3Over Voltage Protection
STATUS
Required
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. Table 27 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 27: Over Voltage Limits
Output Voltage | MIN (V) | MAX (V) |
+3.3 V | 3.9 | 4.5 |
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+5 V | 5.7 | 6.5 |
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+12V1,2,3 | 13.3 | 14.5 |
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+5 VSB | 5.7 | 6.5 |
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7.4Over 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.
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