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How to measure the AXTpower?

Last Update Time: 2019-03-12 14:26:30

We will analyze the DC output and signal of the ATX power supply by using a multimeter to measure the DC voltage of each pin of the ATX power output terminal.


Arbitrarily select a normal ATX power supply, use the power cord to connect the ac mains 220v to the ATX power supply, and place the multimeter in the DC voltage range to measure the DC voltage of each pin on the 20/24-pin output terminal of the ATX power supply (black-table pen connection). 3, 5, 7, 13, 15, 16, 17, ATX power supply can be, red pen connected to other pins).


It is not difficult to find through the actual measurement that in the process of traversing the voltage of all the pins except the GND wire (black cable), a DC voltage of not 0v can be detected on both pins: the output is output through the purple cable. The 9th pin of the terminal (5vsb, often referred to as "purple 5v", "standby 5v"), measures a voltage of about 5v: it is led out via the green cable to the output terminal pin 14 (PSON, which is often on the "green 5v", a DC voltage of 3~5v (5v mostly) is measured. In addition, the voltage measured on the other feet is 0v.


This actual measurement process clearly illustrates the following problem: 5vsb is a special output in the DC output of each ATX power supply. It is produced earlier than +12v, +5v, 3.3v. In fact, as long as the ATX power supply is connected to the ac mains 220v, 5vsb should be generated.


This measurement also clearly reveals the relationship between 5vsb and green 5v: there is good reason to presume that the 5v DC voltage on the PSON is likely to be provided directly or indirectly by the 5vsb (in fact it is true). Even if the PSON is not directly related to the 5vsb, the two should be closely related to the power-up timing of the ATX power supply. Because the PSON is the ATX power supply after the access to the market power followed by the 5vsb's normal and normal functioning of the only control signal.

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This article is from Allicdata Electronics Limited. Reprinted need to indicate the source.