Cooler Master eXtreme Power Plus 500 W Power Supply Review

Secondary Analysis

This power supply has six Schottky rectifiers on its secondary, two for each positive voltage output (+12 V, +5 V and +3.3 V).

The +12 V output is produced by two STPS20S100CT Schottky rectifiers connected in parallel, each one supporting up to 20 A at 150° C (10 A per internal diode). The maximum theoretical current the +12 V 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 (which in this case is made by two 10 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 29 A or 343 W for the +12 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used. The 460 W model uses different rectifiers here, but with the exact same current limits.

The +5 V output is produced by two MBR2045CT Schottky rectifiers in parallel, supporting up to 20 A at 165° C (10 A per internal diode) each. Using the same math we have a maximum theoretical current of 29 A or 143 W for the +5 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used. The 460 W model uses similar devices.

The +3.3 V output is produced by another two MBR2045 Schottky rectifiers in parallel, supporting up to 20 A at 165° C (10 A per internal diode) each. So the maximum theoretical current the +3.3 V output can deliver is of 29 A or 94 W, using the same math described above. As mentioned the real power this line can deliver depends on other factors. The 460 W model uses similar devices.

On this power supply the -12 V is regulated using a 7912 integrated circuit.

So, in summary, the secondary from both 460 W and 500 W models is identical.

Figure 11: +12 V, +5 V and +3.3 V rectifiers.

This power supply uses a WT7527 monitoring integrated circuit, which is in charge of the power supply protections. It supports over voltage (OVP), under voltage (UVP) and over current (OCP) protections. OCP was really activated, as we will talk about later.

Figure 12: Monitoring integrated circuit.

The electrolytic capacitors from the voltage doubler are from Elite (a Thai company) and the capacitors from the secondary are from Ltec (a Taiwanese company).