Rosewill RD600N-2SB-SL-BK Power Supply Review

Secondary Analysis

This power supply uses six Schottky rectifiers on its secondary.

The +12 V output is produced by two MBR40100PT Schottky rectifiers connected in parallel, which can deliver up to 40 A each (20 A per internal diode each, measured at 162° C). The maximum theoretical current the +12 V 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 (which in this case is made by two 20 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 57 A or 684 W for the +12 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.

The +5 V output is produced by two MBR4045PT Schottky rectifiers connected in parallel, which support up to 40 A (20 A per internal diode each, measured at 125° C) each. The maximum theoretical current the +5 V 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 (which in this case is made by two 20 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 57 A or 285 W for the +5 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.

The +3.3 V output is produced by two other MBR4045PT Schottky rectifiers connected in parallel. The maximum theoretical current the +3.3 V 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 (which in this case is made by two 20 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 57 A or 188 W for the +3.3 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.

As you can see this stage is clearly overspec’ed, which is terrific.

Figure 12: Three of the six Schottky rectifiers used on the secondary.

The thermal sensor from this power supply is located on the secondary heatsink, as you can see in Figure 12. This sensor is used to control the fan speed according to the power supply internal temperature and also to shut the power supply down if it implements over temperature protection (OTP).

This power supply uses a PS223 monitoring integrated circuit, which is in charge of the power supply protections, like OCP (over current protection). This IC also provides over voltage protection (OVP), under voltage protection (UVP) and over temperature protection (OTP), but not over power protection (OPP).

Figure 13: Monitoring integrated circuit.

We couldn’t identify the manufacturer from the electrolytic capacitors used on the secondary, which are rated at 105° C.