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Intel ATX Power Supply Design Guide
Version 0.9
3.5 Output Protection
3.5.1 Overvoltage Protection
The overvoltage sense circuitry and reference shall reside in packages that are separate and distinct from the regulator control circuitry and reference. No single point fault shall be able to cause a sustained overvoltage condition on any or all outputs. The supply shall provide
| Table 11: | Overvoltage Protection |
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Output |
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+12VDC | - | - | 15.6 | Volts | ||
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+5VDC | 5.74 | 6.3 | 7.0 | Volts | ||
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+3.3VDC | 3.76 | 4.2 | 4.3 | Volts | ||
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3.5.2 Short Circuit Protection
An output short circuit is defined as any output impedance of less than 0.1 ohms. The power supply shall shut down and latch off for shorting the +3.3VDC, +5VDC, or +12VDC rails to return or any other rail. Shorts between main output rails and +5VSB shall not cause any damage to the power supply. The power supply shall either shut down and latch off or fold back for shorting the negative rails. The +5VSB must be capable of being shorted indefinitely, but when the short is removed, the power supply shall recover automatically or by cycling the PS_ON#. The power supply shall be capable of withstanding a continuous
3.5.3 No Load Operation
No damage or hazardous condition should occur with all the DC output connectors disconnected from the load. The power supply may latch into the shutdown state.
3.5.4 Overcurrent Protection
Overload currents applied to each tested output rail will cause the output to trip before reaching or exceeding 240 VA. For testing purposes, the overload currents should be ramped at a minimum rate of 10 A/s starting from full load.
3.5.5 Output Bypass
The output return may be connected to the power supply chassis. The return will be connected to the system chassis by the system components.
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