Enermax Tomahawk 500 W Power Supply Review

Secondary Analysis

This power supply has four Schottky rectifiers on its secondary.

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. Just as an exercise, we can assume a typical duty cycle of 30%.

The +12 V output is produced by two SBL2060CT Schottky rectifiers, each one capable of delivering up to 20 A (10 A per internal diode at 95° C with a maximum voltage drop of 0.75 V, which is a little too high – i.e., lower efficiency). This gives us a maximum theoretical current of 29 A or 343 W for the +12 V output.

The +5 V output is produced by one MBRF2545CT Schottky rectifier, which can handle up to 25 A (12.5 A per internal diode at 125° C, maximum voltage drop of 0.70 V). This gives us a maximum theoretical current of 18 A or 89 W for the +5 V output.

The +3.3 V output is produced by one STPS3045CW Schottky rectifier, which can handle up to 30 A (15 A per internal diode at 155° C, maximum voltage drop of 0.84 V). This gives a maximum theoretical current of 21 A or 71 W for the +3.3 V output.

Figure 13: +12 V and +3.3 V rectifiers.

Figure 14: +5 V and +12 V rectifiers.

The outputs are monitored by an SG6516DZ integrated circuit, which supports over voltage (OVP), under voltage (UVP) and over current (OCP) protections.

Figure 15: Monitoring integrated circuit.

The secondary capacitors are also from Samxon.