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Secondary Analysis

The Enermax NAXN 80+ 600 W has seven Schottky rectifiers attached to the secondary heatsink.

The maximum theoretical current each line can deliver is given by the formula I / (1 – D) where D is the duty cycle used and I is the maximum current supported by the rectifying diode. As an exercise, we can assume a duty cycle of 30 percent.

The +12 V output uses four SBR30A60CT Schottky rectifiers (30 A, 15 A per internal diode at 110°, 0.60 V maximum voltage drop), giving us a maximum theoretical current of 86 A or 1,029 W for this output.

The +5 V output uses two SBR30U30CT Schottky rectifiers (30 A, 15 A per internal diode at 140° C, 0.54 V maximum voltage drop), giving us a maximum theoretical current of 43 A or 214 W for this output.

The +3.3 V output uses one STPS4045CW Schottky rectifier (40 A, 20 A per internal diode at 150° C, 0.94 V maximum voltage drop), giving us a maximum theoretical current of 29 A or 94 W for this output.

Enermax NAXN 80+ 600 W power supplyFigure 14: The +12 V, +5 V, and +3.3 V rectifiers

This power supply uses an ST9S429 monitoring integrated circuit, which apparently is a rebranded S3515. This chip supports over voltage (OVP), under voltage (UDP), and over current (OCP) protections. There are two +12 V OCP channels, matching the number of +12 V rails advertised by the manufacturer.

Enermax NAXN 80+ 600 W power supplyFigure 15: Monitoring circuit

The electrolytic capacitors available in the secondary are from Teapo and Samxon and labeled at 105° C.

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Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.