Nexus Value 430 Power Supply Review
Secondary Analysis
Contents
The Nexus Value 430 uses a regular design in its secondary, with Schottky rectifiers.
The maximum theoretical current that 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 one S40D60C Schottky rectifier, which supports up to 40 A (20 A per internal diode at 100° C with a 0.70 V maximum voltage drop). This gives us a maximum theoretical current of 29 A or 343 W for the +12 V output.
The +5 V output uses one S30D40C Schottky rectifier, which supports up to 30 A (15 A per internal diode at 125° C with a 0.55 V maximum voltage drop). This gives us a maximum theoretical current of 21 A or 107 W for the +5 V output.
The +3.3 V output uses another S30D40C Schottky rectifier, giving us a maximum theoretical current of 21 A or 71 W for the +3.3 V output.
Figure 14: The +12 V, the +5 V, the +3.3 V, and the +5VSB rectifiers
This power supply uses a WT751002 monitoring integrated circuit, which supports only over voltage (OVP) and under voltage (UVP) protections. The under voltage circuit doesn’t monitor the +12 V rail.
Figure 15: Monitoring circuit
The electrolytic capacitors that filter the outputs are from Teapo and labeled at 105° C, as usual.
