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 Antec.

From all the specs provided on the databook of eachcomponent, 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.

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 the other components used – like the transformer, coils, capacitors, the PCB layout and the wire gauge – 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 a GBU1006 rectifying bridge on its primary stage, which can deliver up to 10 A of continuous current.

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Figure 11: Rectifying bridge on this power supply.

On its primary stage, four power MOSFET transistors are used, two 20N60C3 for the active PFC circuit and two FQA18N50V2 (20 A maximum each) for the switching section, which uses a two-transistor forward configuration. For a better understanding on the relationship between these transistors, we drew a simplified diagram of this section of the NeoPower 550 power supply, see Figure 12.

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Figure 12: Simplified diagram of this power supply showing the location of the four MOSFET transistors.

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Figure 13: MOSFET transistors used on this power supply.

But we are really interested on the secondary part of the power supply.

Its +12 V output is produced by two MBR4060WT Schottky rectifiers installed in parallel, each one supporting up to 40 A continuous current. Thus the +12 V output has a maximum theoretical current of 80 A or 960 W. Of course the true power this line can deliver will depend on the other components used, especially the transformer, the coil and the capacitor.

Its +5 V output is produced by one STPS30L45CW Schottky rectifier, which can handle up to 30 A of continuous current. Thus in theory the +5 V output can deliver up to 150 W.

This power supply has its own +3.3 V rectifier. Cheaper power supplies don’t have this component and the +3.3 V output is produced by a voltage regulator connected to the +5 V line. However, both +3.3 V and +5 V rectifiers are connected to the same transformer output, so the maximum combined current these two outputs can deliver will depend on the transformer. The rectifier used on the +3.3 V output is a STPS30L40CW, which can handle up to 30 A, so in theory the +3.3 V output of this power supply can deliver up to 99 W.

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Figure 14: Rectifiers used on this power supply.

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Figure 15: Second rectifier for the +12 V output.

Antec also chose to add a 7805 voltage regulator connecting the +12 V to the +5 V output, which is probably to simulate a load and allow the power supply to turn on.

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Figure 16: 7805 voltage regulator connected between the +12 V and +5 V outputs.

The electrolytic capacitor used on the active PFC circuit is from Japanese Chemi-Con, while all other electrolytic capacitors are from Taiwanese OST.

This power supply has also a true temperature sensor attached to the heatsink used by the secondary rectifiers, in charge of shutting down the power supply in case of overheating and also controlling the fan speed according to the power supply temperature, which is a great feature to reduce noise, as the fan will rotate on its maximum speed only when needed.