Apevia Turbolink ATX-TL450W-BK Power Supply Review

Secondary Analysis

The +12 V output uses two PR3002 diodes instead of using a single rectifier with two diodes inside. No kidding, the last time we saw this kind of configuration was more than 15 years ago! Each diode supports up to 3 A at 90° C, so the +12 V output has a maximum theoretical current of 6 A or 72 W. Yes, you read it right. This diodes are “fast” not “Schottky,” meaning they have a high voltage drop (1.2 V), i.e., low efficiency.

The +5 V output uses one S16C45C Schottky rectifier, which supports up to 16 A (8 A per internal diode at 125° C, 0.55 V maximum voltage drop), giving us a maximum theoretical current of 16 A or 80 W for the +5 V output.

The +3.3 V output uses one S10C45C Schottky rectifier, which supports up to 10 A (5 A per internal diode at 125° C, 0.70 V maximum voltage drop), giving us a maximum theoretical current of 10 A or 33 W for the +3.3 V output.

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.

Here you can clearly see three things. First, the +5 V output is “stronger” than the +12 V output, which is a typical scenario for power supplies projected more than 10 years ago. Nowadays the most current/power is pulled from the +12 V output (because there is where the CPU and the video cards are connected to) and, therefore, this output should be the “strongest.” Second, the +12 V output uses regular diodes, also showing how obsolete this unit it. And, third, if we add up all the maximum theoretical powers we get 185 W, so it is simply impossible for this power supply to be a 450 W model.

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

To complicate the situation of this power supply, it simply doesn’t have any filtering coil in its secondary, see Figure 13. This will surely make this unit to present noise and ripple levels above the maximum allowed.

Figure 13: No filtering coils in the secondary

The ATX2005 integrated circuit, shown in Figure 11, besides being a PWM controller, also monitors the power supply outputs, presenting overvoltage (OVP) and undervoltage (UVP) protections.

We couldn’t discover the manufacturer of the secondary capacitors.