XFX 650 W XXX Edition Power Supply Review

Secondary Analysis

This power supply has four Schottky rectifiers attached to the secondary heatsink, plus a 7805 voltage regulator that is used for the +5VSB output.

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 SBR40U45CT Schottky rectifiers connected in parallel, each one cabled of delivering up to 40 A (20 A per internal diode at 110° C, maximum voltage drop of 0.52 V). This gives us a maximum theoretical current of 57 A or 686 W for the +12 V output. These rectifiers are more powerful than the ones used on Silencer 610 EPS12V (two 30 A rectifiers).

The +5 V output is produced by one STPS60L30CW Schottky Rectifier, which is capable of delivering up to 60 A (30 A per internal diode at 130° C, 0.38 V typical voltage drop). This gives us a maximum theoretical current of 43 A or 214 W for the +5 V output. This rectifier is way more powerful than the one used on Silencer 610 EPS12V.

The +3.3 V output is produced by one STPS30L30CT Schottky rectifier, which is capable of delivering up to 30 A (15 A per internal diode at 140° C, 0.37 V typical voltage drop), giving us a maximum theoretical current of 21 A or 71 W for the +3.3 V output. This component is similar to the one used on Silencer 610 EPS12V from PC Power & Cooling.

All these numbers are theoretical. The real amount of current/power each output can deliver is limited by other components, especially by the coils used on each output.

Figure 14: +12 V, +5 V and +3.3 V rectifiers.

The outputs are monitored by an HY510N integrated circuit, which supports only over voltage (OVP) and under voltage (UVP) protections. Any other protection that this unit may have is implemented outside this integrated circuit.

Figure 15: Monitoring integrated circuit.

Electrolytic capacitors from the secondary are also Japanese, from Chemi-Con and labeled at 105° C.