Kingwin Mach 1 ABT-700MA1S 700 W Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of Kingwin Mach 1 ABT-700MA1S (a.k.a. Super Flower Aurora 700 W). For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one PBU1005 rectifying bridge in its primary, which support up to 10 A at 100° C. This bridge is attached to an individual heatsink. This is more than adequate rating for a 700 W power supply. The reason why is that at 115 V this unit would be able to pull up to 1,150 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 920 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 bridge.

On the switching section this power supply uses two traditional bipolar power transistors (BJT) in half-bridge configuration instead of two power MOSFET transistors in forward configuration. This is normal on power supplies without active PFC. Traditionally power supplies based on BJT present a lower efficiency. This power supply uses two 2SC4140, which can deliver up to 18 A in pulse mode at 25° C.

Figure 12: Switching transistors.

As we already mentioned, this unit does not feature active PFC circuit. The primary is controlled by a KA7500C integrated circuit, which is physically present on the secondary side of the power supply.

Figure 13: PWM controller.

The two electrolytic capacitors used on the voltage doubler circuit are rated at 105° C, which is great (usually power supplies use capacitors rated at 85° C here). They are from Fuhjyyu, a Taiwanese company.