Rosewill Performance 650 W Power Supply Review
Secondary Analysis
Contents
Rosewill Performance 650 W uses four Schottky rectifiers on its secondary, and only one of them – the one used on the +3.3 V output – didn’t have its markings scratched off. So we couldn’t identify the rectifiers being used on the +12 V (two) and on the +5 V (one) outputs.
The +3.3 V output is produced by one STPS2045CT Schottky rectifier, which is capable of delivering up to 20 A (10 A per internal diode at 155° 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%. So the maximum theoretical current the +3.3 V output can deliver is of 14 A [10 A / (1 – 0.30)] or 47 W (nowhere close to what is printed on the label, by the way). Of course the maximum current (and thus power) this line can really deliver will depend on other components, especially the coil.
Figure 11: +12 V rectifier, +5 V rectifier and +3.3 V rectifier (the other +12 V rectifier is on the opposite side).
Instead of using a monitoring integrated circuit, this power supply implement protections using discrete components. Unfortunately the integrated circuits used on this section had their markings scratched off as well.
The electrolytic capacitors from the secondary are also from Teapo and labeled at 105° C, as usual.