ATX Version 3.0 Multi Rail Desktop Platform Power Supply

Design Guide

ID 336521
Date 01/02/2022

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Document Table of Contents

Short Circuit Protection (SCP) – REQUIRED

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 +3.3V DC, +5V DC, or +12V DC rails to return or any other rail. The +12V1 DC and 12V2 DC should have separate short circuit and over current protection. 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. +5VSB must be capable of being shorted indefinitely. When the short is removed, it is recommended that the power supply shall recover automatically or by cycling PS_​ON#. Optionally, the power supply may latch off when a +5VSB short circuit event occurs. The power supply shall be capable of withstanding a continuous short circuit to the output without damage or overstress to the unit (for example, to components, PCB traces, and connectors) under the input conditions specified in Table 4-1.