This power supply has four Schottky rectifiers on its secondary.
The +12 V output is produced by three STPS20S100CT Schottky rectifiers connected in parallel. Since each one supports up to 20 A at 150º C we have a maximum theoretical current for the +12 V output of 60 A or 720 W. Of course the maximum current (and thus power) this line can really deliver will depend on other components, especially the transformer, the coil, the capacitors and the wire gauge used.
The +5 V output is produced by one SBR30A40CT Schottky rectifier, which supports up to 30 A at 110º C. So the maximum theoretical power the +5 V output can deliver is of 150 W. Of course the maximum current (and thus power) this line can really deliver will depend on other components, especially the transformer, the coil, the capacitor and the wire gauge used, as we mentioned before.
This power supply uses a voltage regulator integrated circuit for regulating the -12 V output (7912). This is a great option for producing this output, as it produces a more stable -12 V output.
click to enlarge
Figure 11: +12 V rectifiers.
click to enlarge
Figure 12: -12 V voltage regulator, +12 V rectifier and +5 V rectifier.
If you are following us you may have noticed that the +3.3 V rectifier is missing. This power supply uses an exotic configuration, where the +3.3 V output is achieved thru a voltage regulator circuit connected to the +12 V output. Since the +3.3 V outputs are being generated using the +12 V rectifiers, the amount of current (and thus power) the +3.3 V and +12 V outputs can pull at the same time are limited by the maximum capacity of these rectifiers. This voltage regulator is located on a small printed circuit board, as you can see on Figure 13.
click to enlarge
Figure 13: +3.3 V voltage regulator.
This power supply uses a WT7527 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. OCP was really activated, as we will talk about later.
click to enlarge
Figure 14: WT7527 monitoring integrated circuit.
The thermal sensor is attached to the secondary heatsink and you can see it on Figure 12. 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), which isn’t the case of iPower 660.
This power supply uses Chinese electrolytic capacitors rated at 85º C from Aishi on the active PFC circuit and Taiwanese capacitors from OST and Ltec rated at 105º C on the secondary.
