This power supply uses a synchronous design on its +12 V output. This means that the rectifiers were replaced with MOSFETs for higher efficiency. The +5 V and +3.3 V outputs still use the traditional design using Schottky rectifiers. Therefore, the design from SilverStone Strider Plus 750 W is somewhat different from the design from Zalman ZM-770XT, even thought visually the two power supplies look alike.

The maximum theoretical current each line can deliver is given by the formula I / (1 - D), where D is the duty cycle used and I is the maximum current supported by the rectifying diode. Just as an exercise, we can assume a typical duty cycle of 30%.

The +12 V output is produced by four IRFB3207 power MOSFETs, each one supporting up to 180 A at 25º or up to 130 A at 100º C in continuous mode, or up to 720 A at 25º C in pulse mode. Wow. This gives us a maximum theoretical current of 371 A or 4,457 W for the +12 V output. Of course the practical limit will depend on other components.

The +5 V output is produced by one STPS40L45CW Schottky rectifier, which supports up to 40 A (20 A per internal diode at 130º C, 0.40 V maximum voltage drop). This gives us a maximum theoretical current of 29 A or 143 W.

The +3.3 V output is produced by another STPS40L45CW Schottky rectifier, giving us a maximum theoretical current of 29 A or 94 W.

All these numbers are theoretical. The real amount of current/power each output can deliver is limited by other components, especially by the coils used on each output.

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Figure 12: +12 V transistors, +5 V and +3.3 V rectifiers, and +5VSB diode.

The outputs are monitored by a PS232 integrated circuit, which supports the following protections: over current (OCP), under voltage (UVP) and over voltage (OVP). Any other protection that this unit may have is implemented outside this integrated circuit.

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Figure 13: Monitoring circuit.

Electrolytic capacitors from the secondary are from Teapo and labeled at 105º C.