PC Power & Cooling Silencer Mk II 650 W Power Supply Review

Secondary Analysis

This power supply uses a synchronous design on its secondary, meaning that the Schottky rectifiers were replaced by MOSFET transistors in order to increase efficiency. On top of that, this unit uses a DC-DC design, meaning that this unit is basically a +12 V power supply, with the +5 V and +3.3 V outputs being generated by two small power supplies attached to the +12 V output.

The +12 V output is generated by two AOT480 MOSFETs, each one capable of handling up to 180 A at 25° C or up to 134 A at 100° C in continuous mode, or up to 500 A at 25° C in continuous mode, with an RDS(on) of only 4.5 mΩ. The +12 V output is also used to generate the +5 V and +3.3 V outputs, but just as an exercise, if we pulled all power from the +12 V output this unit would have a maximum theoretical current at 100° C of 191 A or 2,297 W. The 750 W model uses one additional transistor here.

Figure 13: Transistors of the +12 V rail

The +5 V and +3.3 V outputs are generated by two small power supplies available on small daughterboards attached to the +12 V rail. Each of these power supplies is comprised of four IPD060N03L MOSFETs (50 A at 100° C, 6 mΩ resistance) and one APW7073 PWM controller.

Figure 14: One of the DC-DC converters

This power supply uses a PS224 monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP) and over current (OCP) protections. The over current protection circuit available in this integrated circuit has four channels, one for +3.3 V, one for +5 V, and two for +12 V. However, in this power supply only one +12 V OCP channel is used, as it has a single-rail design.

Figure 15: Monitoring circuit

The electrolytic capacitors available in the secondary are from also Japanese, from Chemi-Con, and labeled at 105° C. The secondary also has some solid capacitors.

One curious thing we noticed was the adaptation the manufacturer did to add an extra electrolytic capacitor to the +12 V rail (see in Figure 16). This adaptation is also present in the 750 W model from this series.

Figure 16: Additional electrolytic capacitor for the +12 V rail

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In Figure 17, you can see the power supply label containing all the power specs.

Figure 17: Power supply label

This power supply has a single +12 V rail, so there is not much to talk about here.

Let’s now see if this power supply can really deliver 650 W.