Secondary Analysis

This power supply has four Schottky rectifiers on its secondary.

The +12 V output is produced by two SBR40U60PT Schottky rectifiers connected in parallel, each one supporting up to 40 A at 150º C (20 A per internal diode). The maximum theoretical current the +12 V 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 (which in this case is made by two 20 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 57 A or 684 W for the +12 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.

The +5 V output is produced by one DF40SC4 Schottky rectifier, which supports up to 40 A at 106º C (20 A per internal diode). The maximum theoretical current the +5 V 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 (which in this case is made by one 20 A diode). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 29 A or 143 W for the +5 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.

The +3.3 V output is produced by another DF40SC4 Schottky rectifier, which supports up to 40 A at 106º C (20 A per internal diode). So the maximum theoretical power the +3.3 V output can deliver using the above math is of 94 W.

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Figure 13: +3.3 V, +12 V and +5 V rectifiers.

This power supply uses a PS231S monitoring integrated circuit, which is in charge of the power supply protections, like OCP (over current protection). Unfortunately there is no datasheet for this component on the manufacturer’s website, so we couldn’t check what protections it really supports. Analyzing the printed circuit board from the reviewed power supply we could clearly see each +12 V virtual rail connected to this integrated circuit.

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Figure 14: PS231S monitoring integrated circuit.

The thermal sensor is attached to the secondary heatsink and you can see it on Figure 14 (green component). This sensor is used to control the fan speed according to the power supply internal temperature and to shut down the power supply in an overheating situation, if the power supply implements over temperature protection (OTP). Enermax says that PRO82+ 525 W has this protection set at 95º C, bue we couldn't test this as we couldn't put this power supply to run at such high temperature.

This power supply uses only Japanese electrolytic capacitors, with capacitors from Matsushita (Panasonic) on the active PFC circuit (rated at 85º C) and Chemi-Con on the secondary (rated at 105º C).