Dynex 400 W Power Supply Review

Power Distribution

This power supply uses four Schottky rectifiers on its secondary.
Since this power supply is based on the half-bridge design to calculate the maximum theoretical current/power for each output is easy: we can simply add the maximum current from each diode.
The +12 V output is produced by two MBR20H100CT Schottky rectifiers connected in parallel, which can deliver up to 20 A each (10 A per internal diode, measured at 162° C), thus the maximum theoretical current the +12 V line can deliver is of 40 A, which equals to 480 W. The maximum current this line can really deliver will depend on other components. The Green Star 450 W model we reviewed used different rectifiers, STPS20S100C, but they have the exact same specs from the rectifiers used on this power supply.
The +5 V output is produced by one STPS30S45CW Schottky rectifier, which supports up to 30 A (15 A per internal diode, measured at 135° 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. This is the exact same rectifier used on Green Star 450 W.
The +3.3 V output is produced by another STPS30S45CW Schottky rectifier, which supports up to 30 A (15 A per internal diode, measured at 140° C). So the maximum theoretical power the +3.3 V output can deliver is of 99 W. Of course the maximum current (and thus power) this line can really deliver will depend on other components. This is the exact same rectifier used on Green Star 450 W.
Even though this power supply has a separated rectifier for the +3.3 V output, this rectifier is connected to the same transformer output as the +5 V line, so the maximum current +5 V and +3.3 V can pull together is limited by the transformer.

Figure 12: The four Schottky rectifiers used on the secondary.

This power supply thermal sensor is located close to one of the ends of the secondary heatsink, as you can see in Figure 13. This sensor is used to control the fan speed according to the power supply internal temperature and also to shut the power supply down if it implements over temperature protection (OTP), which isn’t the case of this power supply.

Figure 13: Thermal sensor.

This power supply uses a SG6105 monitoring integrated circuit, which is in charge of the power supply protections. This IC features over voltage protection (OVP), under voltage protection (UVP), short-circuit protection (SCP) and over power protection (OPP). As you can see this IC doesn’t support over current protection (OCP) but Huntkey implemented this protection using a quad-comparator integrated circuit (AS339).

Figure 14: Protection integrated circuits.

Analyzing the printed circuit board we could clearly see each +12 V rail connected to the OCP circuit. Also, each +12 V rail had its own filtering circuit (own coil and own electrolytic capacitor), which is nice to see.
The electrolytic capacitors used on the secondary are from Teapo and Fcon and rated at 105° C.
In summary, Dynex 400 W (Huntkey Green Star 400 W) is IDENTICAL to Huntkey Green Star 450 W.