Engineers must be wary of safety, electromagnetic-compatibility, and thermal-management factors when installing open-frame and U-channel power supplies.
Typically, power supplies are supplied in what is known by the industry as an open-frame format. Open frame generally describes a PCB-only-construction, component power supply designed to be installed into an end-equipment application that provides the enclosure for the entire product (Fig. 1).
1. Power supplies are often provided in an open frame, as shown, relying on the end-application to provide a suitable enclosure to provide additional safety and EMC protection for the PCB.
Another common format for power supplies for integration into end equipment is the U channel, where the power-supply PCB is installed in a U-shaped, usually aluminum, chassis that’s often used as a part of the thermal management of the power semiconductors (Fig. 2). It also provides multiple fixing options for the equipment manufacturer to install the supply into the final assembly.