High Power Direct12 BR 850 W Power Supply Review

Secondary Analysis

The High Power Direct12 BR 850 W uses a regular design in its secondary, with Schottky rectifiers.

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. As an exercise, we can assume a duty cycle of 30 percent.

The +12 V output uses four KCQ60A06 Schottky rectifiers (60 A, 30 A per internal diode at 69° C, 0.67 V maximum voltage drop). This gives us a maximum theoretical current of 171 A or 2,057 W for the +12 V output.

The +5 V output uses two PFR30L45CT Schottky rectifiers (30 A, 15 A per internal diode at 110° C, 0.52 V maximum voltage drop), giving us a maximum theoretical current of 43 A or 214 W for this output.

The +3.3 V output uses another two PFR30L45CT Schottky rectifiers (30 A, 15 A per internal diode at 110° C, 0.52 V maximum voltage drop), giving us a maximum theoretical current of 43 A or 141 W for this output.

Figure 14: The +5 V, +3.3 V, and +12 V rectifiers

Figure 15: The +12 V, +3.3 V, +5 V, and +5VSB rectifiers

This power supply uses a PS224 monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP), and over current (OCP) protections. This chip offers two +12 V channels. However, the manufacturer decided to use only one of them and provide a single +12 V rail.

Figure 16: Monitoring circuit

The electrolytic capacitors that filter the outputs are from Teapo and labeled at 105° C, as usual. On the modular cabling system printed circuit board, however, the manufacturer added Japanese capacitors, also from Chemi-Con, and some solid models. They seem to be jerry-rigged to this printed circuit board, though.