In Win Commander 650 W Power Supply Review

Secondary Analysis

Commander 650 W uses four Schottky rectifiers on its secondary.

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%. Of course the maximum current (and thus power) this line can really deliver will depend on other components, especially the coil.

The +12 V output is produced by two STPS4045CW Schottky rectifiers in parallel, each one supporting up to 40 A (20 A per internal diode at 130° C). This gives us a maximum theoretical current of 57 A [(20 A x 2)/(1 – 0.30)] or 686 W for the +12 V output. As we suspected, this 650 W product uses rectifiers with lower current limits than other 750 W CWT-based models we’ve reviewed (which use two 60 A rectifiers).

The +5 V output is produced by one STPS40L45CW Schottky rectifier, which has the same current specs as STPS4045CW but featuring a lower voltage drop (that is what the “L” in the name stands for), i.e., they waste less power and thus provide higher efficiency. So the maximum theoretical current the +5 V output can deliver is of 29 A [20 A/(1 – 0.30)] or 143 W. This is exactly the same rectifier used by 750 W CWT-based units we’ve reviewed to date.

The +3.3 V output is produced by another STPS40L45CW Schottky rectifier. So the maximum theoretical current the +3.3 V output can deliver is of 29 A or 94 W. This is exactly the same rectifier used by 750 W CWT-based units we’ve reviewed to date.

Figure 12: +12 V rectifier, +5 V rectifier and +3.3 V rectifier (the other +12 V rectifier is on the opposite side).

This power supply uses a PS229 monitoring integrated circuit, which is in charge of the power supply protections. Unfortunately the datasheet for this component isn’t available on the manufacturer’s website, so we couldn’t check what protections are really implemented on this power supply.

The electrolytic capacitors from the secondary are also from Samxon and labeled at 105° C, as usual. These are the same caps used by CWT-750VH and Thermaltake Toughpower 750 W, but Corsair TX750W uses Japanese models.

In summary this power supply, which is a relabeled CWT-650VH, uses the same project as CWT-750VH and Corsair TX750W, but with switching transistors and +12 V rectifiers with lower current limits.