Seventeam ST-420BKV 420 W Power Supply Review

Primary Analysis

Seventeam ST-420BKV uses one PBU1005 rectifying bridge, which can deliver up to 10 A (rated at 100° C). No heatsink was used to cool down this component. This component is clearly overspec’ed: 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.

On the switching section two 2SC3320 NPN power transistors are used under the half-bridge configuration, which is a typical configuration used by power supplies without active PFC. Note that the transistors are regular BJT transistors and not MOSFET ones. Each transistor has a maximum rated current of 15A @ 25° C.

Figure 9: Two power NPN transistors are used on the switching section.