Secondary Analysis

This power supply uses four Schottky rectifiers on its secondary. 

The +12 V output is produced by two STPS6045CW Schottky rectifiers connected in parallel, which can deliver up to 60 A each (measured at 130º C), thus the maximum theoretical current the +12 V line can deliver is of 120 A, which equals to 1,440 W. The maximum current this line can really deliver will depend on other components, especially the transformer, the coil, the capacitor and the wire gauge used.

The +5 V output is produced by one STPS60L30CW Schottky rectifier, also supporting up to 60 A (measured at 130º C). This equals to 300 W. Of course the maximum current this line can really deliver will depend on other components, especially the transformer, the coil, the capacitor and the wire gauge used, as mentioned before.

And the +3.3 V output is produced by one STPS30L30CT Schottky rectifier, supporting up to 30 A (measured at 140º C). This equals to 99 W. As mentioned, the maximum current this line can really deliver will depend on other factors.

Even though the +5 V line and the +3.3 V line have separated rectifiers, they share the same transformer output. So the maximum current both lines can deliver will depend a lot on the transformer.

On Figures 15 and 16 you can see the four power Schottky rectifiers used on the secondary section of this power supply and a 7805 voltage regulator which is probably used to simulate a load and allow the power supply to turn on.

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Figure 15: Power rectifiers used on the secondary.

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Figure 16: Power rectifiers used on the secondary.

This power supply uses a semiconductor thermal sensor, which is very small and installed on the solder side of the printed circuit board, right below the transformer ground outputs. This sensor is used to control the fan speed according to the power supply internal temperature and also to shut it down in the case of an overheating situation.

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Figure 17: Thermal sensor.

On this power supply all electrolytic capacitors are rated at 105º C and the capacitors from the secondary are Japanese, from Chemi-Con.

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