Printed circuits containing fuse elements and the method of making this

Abstract

A fusible printed circuit includes one or more conductors extending along a dielectric substrate. The circuit can be flexible or rigid. Each conductor is comprised of a layer of electrically conductive material and has one or more gaps formed in the conductive layer at locations opposite a segment of the fusible material so that electrical current flowing through each conductor is required to pass, in its entirety, through the segment of fusible material at the location of each gap in the layer of conductive material. The integral fuses are designed to specific electrical parameters and may be located randomly along circuit runs. The fusible material is cold welded to the conductors at the gaps. Pressure concentrators support the fuses and minimize motion stress on the fuses. The fuses can be sealed within a protective overlay which captures debris when the fuses are blown and controlled venting of the debris can also be provided. The use of such a circuit to incorporate a variety of fuses having different fuse ratings into the conductive paths of a printed circuit is also disclosed, as are methods of making fusible flexible circuits.