Corsair TX750M Power Supply Review

Secondary Analysis

The Corsair TX750M uses a DC-DC design in its secondary, meaning that this power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs being generated by two smaller switch-mode power supplies connected to the main +12 V output. This design is proving to be the best solution to achieve high efficiency.

The +12 V output uses five SBR40U60CT Schottky rectifiers (40 A, 20 A per diode at 150° C, 0.60 V maximum voltage drop). They are configured as shown in Figure 15.

Figure 14: The +12 V rectifiers

Figure 15: How the rectifiers are connected

The +5 V and +3.3 V power supplies are located on the same printed circuit board as the modular cabling system, as you can see in Figures 16 and 17. They use one APW7159 PWM controller, and each output is driven by four AP72T03GH MOSFETs (up to 62 A at 25° C or 44 A at 100° C in continuous mode, or up to 190 A at 25° C in pulse mode, 9 mΩ resistance).

Figure 16: The DC-DC converters

Figure 17: The DC-DC converters

This power supply uses a PS113 monitoring integrated circuit, which is a very simple chip that supports only over voltage (OVP) and short-circuit (SCP) protections. The protection circuitry also uses an LM393 voltage comparator, probably to add the missing protections.

Figure 18: Monitoring circuit

The electrolytic capacitors that filter the +5 V and +3.3 V rails are solid, while the capacitors that filter the +12 V rails are Japanese, from Chemi-Con.