his page we will take an in-depth look at the primary stage of PC Power & Cooling Silencer Mk II 750 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses one US30KB80R rectifying bridge, attached to the same heatsink used by the active PFC and switching transistors. This bridge supports up to 30 A at 97° C so, in theory, you would be able to pull up to 3,450 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 2,760 W without burning itself out. Of course, we are only talking about these components, and the real limit will depend on all the other components in this power supply.
The active PFC circuit uses two IPI60R125CP MOSFETs, each one capable of delivering up to 25 A at 25° C or up to 16 A at 100° C in continuous mode (note the difference temperature makes), or up to 82 A in pulse mode at 25° C. These transistors present a 125 mΩ resistance when turned on, a characteristic called RDS(on). The lower this number the better, meaning that the transistors will waste less power and the power supply will have a higher efficiency.
This power supply uses two electrolytic capacitors to filter the output from the active PFC circuit. The use of more than one capacitor here has absolute nothing to do with the “quality” of the power supply, as laypersons may assume (including people without the proper background in electronics doing power supply reviews around the web). Instead of using one big capacitor manufacturers may choose to use two or more smaller components that will give the same total capacitance, in order to better accommodate space on the printed circuit board, as two capacitors with the same total capacitance are physically smaller than a single capacitor with equivalent capacitance. The NZXT HALE90-850-M uses two 390 µF x 400 V capacitors connected in parallel, the equivalent of one 780 µF x 400 V capacitor. They are Japanese, manufactured by Chemi-Con, and labeled at 105° C.
Instead of using a PWM/PFC combo controller, this power supply uses two separate circuits, and the active PFC circuit is controlled by an NCP1653A integrated circuit.
In the switching section, another two IPI60R125CP MOSFET transistors are used. The specifications for these transistors are already published above.
Power supplies from the NZXT HALE90 series use an LLC resonant switching design, also known as a series parallel resonant converter. The switching transistors are controlled by an SF29601 controller, and we couldn’t find more information about this chip. We believe that the original manufacturer got a resonant controller and relabeled it, as SF stands for “Super Flower.” Interesting enough the controller is placed on the secondary of the power supply.
Now let’s take a look at the secondary of this power supply.