Antec VP450 Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of the Antec VP450. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one GBU1006 rectifying bridge, which is attached to an individual heatsink. This bridge supports up to 10 A at 100° C, so in theory, you would be able to pull up to 1,150 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 920 W without burning itself out. Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply.

Figure 10: Rectifying bridge

As mentioned before, this power supply doesn’t have a PFC circuit.

The voltage doubler circuit uses two 820 µF x 200 V electrolytic capacitors from Teapo and labeled at 85° C.

Usually, power supplies without a PFC circuit are based on the obsolete half-bridge design; the Antec VP450 uses the two-transistor forward configuration, which is great.

In the switching section, two JCS18N50FH MOSFETs are used in the traditional two-transistor forward configuration, supporting up to 18 A at 25° C or 11 A at 100° C in continuous mode, or up to 72 A at 25° C in pulse mode, with an RDS(on) of 270 mΩ.

Figure 11: The switching transistors

The switching transistors are controlled by a UC3845B PWM controller.

Figure 12: PWM controller

Let’s now take a look at the secondary of this power supply.