Zalman ZM500-RS Power Supply Review
Primary Analysis
Contents
On this page we will take an in-depth look at the primary stage of Zalman ZM500-RS. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses one GBU1006 rectifying bridge in its primary, which can deliver up to 10 A at 100° C. At 115 V this unit would be able to pull up to 1,150 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 920 W without burning this component. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.
Figure 9: Rectifying bridge.
On the active PFC circuit two FDPF16N50 power MOSFET transistors are used, each one capable of delivering up to 16 A at 25° C or 9.6 A at 100° C in continuous mode (note the difference temperature makes), or up to 64 A in pulse mode at 25° C. These transistors present a resistance of 380 mΩ when turned on, a characteristic called RDS(on). This number indicates the amount of power that is wasted, so the lower this number the better, as less power will be wasted thus increasing efficiency.
This power supply uses a Taiwanese capacitor from Teapo labeled at 85° C to filter the output from the active PFC circuit.
In the switching section, two STP14NK50ZFP power MOSFET transistors are used, each one capable of delivering up to 14 A at 25° C or 7.6 A at 100° C in continuous mode, or up to 48 A at 25° C in pulse mode, with an RDS(on) of 380 mΩ.
Figure 11: Switching transistors.
The switching transistors are connected using a design called “LLC resonant,” also known as a series parallel resonant converter, being controlled by an L6598 integrated circuit. So far we’ve seen only a few power supplies using this kind of design, like Seasonic X-Series 650 W, Thermaltake Toughpower 800 W and SilverStone Nightjar 400 W.
Figure 12: Resonant controller.
The active PFC circuit is controlled by a separated integrated circuit, which we couldn’t read its markings, but we assume it is an ICE1PCS02.
Now let’s take a look at the secondary of this power supply.