Corsair HX1000W Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of HX1000W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses two GBU1506 rectifying bridges connected in parallel in its primary, each one capable of delivering up to 15 A at 100° C (if a heatsink is used, which is the case), so the total capacity is of 30 A at 100° C. This stage is amazingly overspec’ed: at 115 V this unit would be able to pull up to 3,450 W from the power grid; assuming 80% efficiency, the bridges would allow this unit to deliver up to 2,760 W without burning this component. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Figure 11: Rectifying bridges.

These bridges are shared among the two 500 W power supplies that exist inside HX1000W. But all sections from now on are really separated. As we mentioned, usually power supplies using two transformers share at least the active PFC circuit. On Corsair HX1000W everything is separated, including the active PFC circuit: separated switching transistors, separated PWM/PFC controlling circuit, separated transformers and separated outputs. So we are really talking about two independent power supplies here (well, not exactly, as they still share the rectifying bridges).

Each active PFC circuit uses two 20N60C3 power MOSFET transistors, the same used by several other power supplies we looked. Each one is capable of handling up to 300 A @ 25° C in pulse mode (which is the case) or up to 45 A @ 25° C or 20 A @ 110° C (note the difference temperature makes).

Figure 12: Active PFC transistors and diode.

On each switching section this power supply uses two other 20N60C3 transistors, on the traditional two-transistor forward configuration. The specs for these transistors are published above.

Figure 13: Switching transistors.

Each primary is controlled by a CM6800 active PFC/PWM controller combo installed on a small printed circuit board.

Figure 14: Active PFC/PWM controller combo.

Each active PFC stage uses one Japanese electrolytic capacitor from Chemi-Con rated at 105° C. This is outstanding.

Thermaltake Toughpower 1,500 W and Corsair HX1000W are identical on this stage.