Enermax ECO80+ 620 W Power Supply Review

Secondary Analysis

This power supply uses four Schottky rectifiers on its secondary.

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. Just as an exercise, we can assume a typical duty cycle of 30%.

The +12 V output is produced by two SBR40U60PT (40 A, 15 A per internal diode at 25° C, maximum voltage drop of 0.60 V) connected in parallel. This gives us a maximum theoretical current of 57 A or 686 W for the +12 V output.

By the way, we are now talking about the voltage drop presented by the rectifiers. This parameter shows how much voltage is wasted by the rectifier. The lower this number is, the better, as less voltage is wasted, increasing efficiency.

The +5 V output is produced by one DF40SC4 Schottky rectifier (40 A, 20 A per internal diode at 106° C, maximum voltage drop of 0.55 V), giving us a maximum theoretical current of 29 A or 143 W for this output.

The +3.3 V output is produced by one DF30SC4 Schottky rectifier (30 A, 15 A per internal diode at 112° C, maximum voltage drop of 0.55 V), giving us a maximum theoretical current of 21 A or 71 W for this 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.

Figure 13: Rectifiers.

The outputs are monitored by a PS223 integrated circuit, which supports under voltage (UVP), over voltage (OVP), over current (OCP) and over temperature (OTP) protections. Any other protection that this unit may have is implemented outside this integrated circuit.

Figure 14: Monitoring integrated circuit.

Most electrolytic capacitors from the secondary are from CEC, a Hong Kong-based company.