OCZ GameXstream 700 W Power Supply

Secondary Analysis

This power supply uses eight Schottky rectifiers on its secondary and they are all the same model: MBRP3045N. This is really unique, as usually power supplies use a different rectifier for each output. Four of them are used for the +12 V output, two of them are used for the +5 V output and two of them are used for the +3.3 V output – even though the +3.3 V output uses a separated rectifier, it is connected at the same transformer outputs as the +5 V line.

Each MBRP3045N rectifier can handle up to 30 A (15 A per internal diode, rated at 100° C).

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%.

This would give us a maximum theoretical current of 86 A [(15 A x 4)/(1 – 0.30)] or 1,029 W for the +12 V output, 43 A [(15 A x 2)/(1 – 0.30)] or 214 W for the +5 V output and 43 A or 141 W for the +3.3 V output. The maximum current each line can really deliver will depend on other components, in particular the coil used.

Figure 13: The eight Schottky rectifiers used on the secondary.

In Figure 14, you can see the thermal sensor located under the secondary heatsink, which controls the fan speed acording to the power supply internal temperature.

Figure 14: Thermal sensor.

This power supply uses Taiwanese electrolytic capacitors from Teapo, CapXon and OST. The big electrolytic capacitor from the active PFC circuit is rated 85° C while all other smaller capacitors are rated 105° C.