On this page we will take an in-depth look at the primary stage of V-Power 550 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one T15XB80 rectifying bridge in its primary, capable of delivering up to 15 A at 100º C if a heatsink is used – which is not the case – but only 3.2 A at 25º C if a heatsink is not used. The difference is outrageous and Huntkey should have added a heatsink on this component. The current limit for this component is simply too low (3.2 A).  At 115 V this unit would be able to pull only up to 368 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver only up to 294 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. This is the same component used on Huntkey Titan 650 W (first version of Rocketfish 700 W, RF700WPS, the current version RF700WPS2 is manufactured by CWT), but at least this other product had a heatsink attached to it, which increased the current limit.

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Figure 10: Rectifying bridge.

V-Power 550 W uses two 2SC3320 power NPN transistors on its switching section using the half-bridge design, supporting up to 15 A at 25º C (unfortunately the manufacturer from these transistors do not say how much they can deliver at higher temperatures). These are the same transistors used on Green Star 550 W and Titan 650 W (Rocketfish 700 W) from Huntkey. These transistors are more “powerful” than the ones used on the 350 W, 400 W and 450 W versions from Green Star power supplies. Like it happened with Green Star 550 W, these were the components that burned when we tried to pull 550 W from the reviewed power supply.

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Figure 11: One of the two switching transistors.

The two big electrolytic capacitors from the primary are from Teapo (a Taiwanese company) and rated at 85º C.