TiVECO TVPS450 Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of the T
iVECO TVPS450. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one KBL406G rectifying bridge, which is not attached to a heatsink. This bridge supports up to 4 A at 50° C, so in theory, you would be able to pull up to 460 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 368 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. Here we can clearly see that it is impossible for this power supply to be a 450 W product.

Figure 10: Rectifying bridge

This power supply doesn’t have a PFC circuit. The electrolytic capacitors from the voltage doubler circuit are from a company called Jay’Long and labeled at 105° C.

In the switching section, one 2SK3797 MOSFET is employed using the single-transistor forward configuration. This transistor supports up to 13 A at 25° C or 52 A at 25° C in pulse mode. (Unfortunately, the manufacturer doesn’t state the current limit at 100° C.) This transistor presents a 320 mΩ resistance when turned on, a characteristic called RDS(on). The lower the number is, the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

Figure 11: The main switching transistor and the +5VSB switching transistor

The primary is managed by a UC3842 PWM controller.

Figure 12: PWM controller

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