OCZ ModXStream Pro 500 W Power Supply Review

Secondary Analysis

This power supply has five Schottky rectifiers on its secondary, plus a diode in charge of the +5VSB output rectification.

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 ESAD83-004 (“D83-004”) Schottky rectifiers connected in parallel, each one supporting up to 30 A (15 A per internal diode at 90° C, 0.55 V maximum voltage drop). This gives us a maximum theoretical current of 43 A or 514 W for the +12 V output. The 600 W model uses two rectifiers with double the current limit, so it has double the theoretical current/power limit from the 500 W model on this output.

The +5 V output is produced by one ESAD83-004 Schottky rectifier, which is capable of delivering up to 30 A (15 A per internal diode at 90° C, 0.55 V maximum voltage drop), giving us a maximum theoretical current of 21 A or 107 W for the +5 V output. The 600 W model uses two of this rectifier connected in parallel, so it has double the theoretical current/power limit on this output.

The +3.3 V output is produced by another two ESAD83-004 Schottky rectifiers, giving us a maximum theoretical current of 43 A or 141 W for the +3.3 V output. This is exactly the same configuration used on the 600 W model.

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 13: +12 V, +5 V and +3.3 V rectifiers.

The outputs are monitored by a PS224 integrated circuit, which supports over voltage (OVP), under voltage (UVP) and over current (OCP) protections, supporting two +12 V channels and also monitoring +5 V and +3.3 V outputs. This is the same component used on the 600 W model.

Figure 14: Monitoring integrated circuit.

All capacitors from the secondary are also from CEC.