Zalman ZM360B-APS Power Supply Review

Secondary Analysis

This power supply has four Schottky rectifiers on its secondary using the same configuration used by high-end power supplies.

The +12 V output is produced by two MBR2060CT Schottky rectifiers connected in parallel, which support up to 20 A (10 A per internal diode) at 125° C each. The maximum theoretical current the +12 V 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 (which in this case is made by two 10 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 29 A or 343 W for the +12 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.

The +5 V output is produced by a MBRP3045N Schottky rectifier, which supports up to 30 A (15 A per diode) at 100° C each. The maximum theoretical current the +5 V 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 (which in this case is made by one 15 A diode). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 21 A or 107 W for the +5 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.

The +3.3 V output is produced by another MBRP3045N Schottky rectifier, which supports up to 30 A (15 A per diode) at 100° C. Using the same math we would get a maximum theoretical power of 71 W for the +3.3 V output.

Figure 15: +3.3 V, +5 V and +12 V rectifiers.

This power supply uses separated filtering stages for each 12 V virtual rail, which is great.

This power supply uses a PS223 monitoring integrated circuit, which is in charge of the power supply protections, like OCP (over current protection). OCP was really activated, as we will talk about later. This IC also provides over voltage protection (OVP), under voltage protection (UVP) and over temperature protection (OTP), but not over power protection (OPP).

Figure 16: PS223 monitoring integrated circuit.

The thermal sensor is located under the secondary heatsink, as you can see in Figure 17 (we took this picture with the heatsink removed). This sensor is used to control the fan speed according to the power supply internal temperature and to shut down the power supply in an overheating situation. As we mentioned, the monitoring IC supports this protection and Zalman says this unit features this protection. We, however, couldn’t test this feature, as the power supply was always working very cool.

Figure 17: Thermal sensor.

On this power supply all electrolytic capacitors are Taiwanese, from CapXon, with the active PFC capacitor rated at 85° C and the secondary capacitors rated at 105° C.