OCZ StealthXStream 2 600 W Power Supply Review

Secondary Analysis

This power supply has eight MBR3045CT Schottky rectifiers (30 A maximum current, 15 A per internal diode at 100° C, 0.84 V maximum voltage drop), all attached to the secondary heatsink. This is an improvement over the old StealthXStream 600 W, which used weaker rectifiers (MBR2045CT, 20 A maximum current) for the +12 V output. So the new StealthXStream 2 600 W has a higher maximum theoretical current on its +12 V output. It is important to note, however, that other power supplies based on the same design, like the Zalman ZM600-HP and OCZ GameXStream 700 W, use eight of the MBT3045CT’s.

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 generated using four of the available rectifiers , giving us a maximum theoretical current of 86 A or 1,029 W for the +12 V output.

The +5 V output is generated using two of the available rectifiers, giving us a maximum theoretical current of 43 A or 214 W.

The +3.3 V output is generated using the other two available rectifiers, giving us a maximum theoretical current of 43 A or 141 W.

Of course these are all theoretical figures. The real current limits will depend on other components, especially on the coil used.

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

The outputs are monitored by a PS223 integrated circuit. This circuit supports over voltage (OVP), under voltage (UVP), over temperature (OTP), and over current (OCP) protections. This circuit offers four over current protection channels (one for +3.3 V, one for +5 V, and two for +12 V). A WT7518D integrated circuit expands the number of +12 V over current protection channels to four, correctly matching the number of +12 V rails announced by the manufacturer.

Figure 15: Monitoring circuit

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