We were very curious to check what components were chosen for the power section of this power supply and also how they were set together, i.e. the design used. We were willing to see if the components could really deliver the power announced by Zalman.

From all the specs provided on the databook of each component, we are more interested on the maximum continuous current parameter, given in ampères or amps for short. To find the maximum theoretical power capacity of the component in watts we need just to use the formula P = V x I, where P is power in watts, V is the voltage in volts and I is the current in ampères.

We also need to know under which temperature the component manufacturer measured the component maximum current (this piece of information is also found on the component databook). The higher the temperature, the lower current semiconductors can deliver. Currents given at temperatures lower than 50º C are no good, as temperatures below that don’t reflect the power supply real working conditions.

Keep in mind that this doesn’t mean that the power supply will deliver the maximum current rated for each component as the maximum power the power supply can deliver depends on other components used – like the transformer, coils, capacitors, the PCB layout, the wire gauge and even the width of the printed circuit board traces – not only on the specs of the main components we are going to analyze.

For a better understanding of what we are talking here, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses two GBU606 rectifying bridges on its primary stage, which can deliver up to 6 A each (rated at 100º C), so the total current the rectifying section of this power supply can handle is of 12 A. OCZ GameXstream 700 W uses two GBU605 bridges, which have these same specs.

The active PFC circuit from this power supply uses three power MOSFET transistors (20N60C3 – the same one used by several other power supplies we took a look, like Antec Neo 550 HE, Cooler Master iGreen Power 430 W, Corsair HX620W, Thermaltake Toughpower 750 W and OCZ GameXstream 700 W), just like OCZ GameXstream 700 W. Zalman ZM600-HP and OCZ GameXstream 700 W are the only two power supplies we’ve seen using such design. All other high-end power supplies we’ve seen to date use only two transistors (except Enermax Galaxy 1000 W, which uses four transistors). Each 20N60C3 can handle up 300 A @ 25º C each in pulse mode (which is the case).

The active PFC transistors and the PFC diode are installed on the same heatsink. Usually the active PFC transistors are on the same heatsink as the switching transistors, which isn’t the case for this power supply.

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Figure 16: Active PFC transistors and PFC diode.

On the switching section two FQPF18N50V2 power MOSFET transistors in two-transistor forward configuration are used, and each one has a maximum rated current of 72 A in pulsating mode, which is the mode used, as the PWM circuit feeds these transistors with a square waveform. Interesting to note that these are the same transistors used by OCZ GameXstream 700 W and Corsair HX620W power supplies.

The two rectifying bridges are installed on the same heatsink used by the switching transistors.

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Figure 17: Switching transistors and rectifying bridges.

Like OCZ GameXstream 700 W this power supply uses eight Schottky rectifiers on its secondary and they are all the same model: MBRP3045N. This is really unique, as usually power supplies use a different rectifier for each output. Four of them are used for the +12 V output, two of them are used for the +5 V output and two of them are used for the +3.3 V output – even though the +3.3 V output uses a separated rectifier, it is connected at the same transformer outputs as the +5 V line.

Each MBRP3045N rectifier can handle up to 30 A (rated at 100º C). This means that in theory the +12 V output is capable of delivering up to 120 A (1,440 W), the +5 V output is capable of delivering up to 60 A (300 W) and the +3.3 V output is capable of delivering up to 60 A (198 W). As we said earlier, the maximum power the power supply can deliver depends on other components used – like the transformer, coils, capacitors, the PCB layout, the wire gauge and even the width of the printed circuit board traces.

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Figure 18: The eight Schottky rectifiers used on the secondary.

On Figure 19 you have a better picture of the heatsink used on the secondary.

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Figure 19: Secondary heatsink.

This power supply uses Taiwanese electrolytic capacitors from Teapo, CapXon and OST. The big electrolytic capacitors from the active PFC circuit is rated 85º C while all other smaller capacitors are rated 105º C. This power supply uses exactly the same capacitors as OCZ GameXstream 700 W.