Patent ID: 6300859
Filing Date: 2001-10-09
Classification: H01C

Abstract:
An electrical overcurrent sensing device having a top major surface and a bottom major surface and including a patterned metal foil conductor defined along the top major surface, the metal foil conductor having a first electrode region at one end region, a second electrode region at an opposite end region, and a current-concentrating region extending between the first electrode region and the second electrode region; a planar sheet of a composition which exhibits PTC behavior, the planar sheet having a first major surface in thermal contact with at least the current-concentrating region of the patterned metal foil conductor and having an opposite second major surface; a patterned metal foil control current collecting layer connected to the second major surface of the planar PTC sheet having a surface area generally limited to and in substantial alignment with the current-concentrating region such that heat generated in the current-concentrating region from electrical overcurrent flowing through the metal foil conductor is transferred to the planar sheet exhibiting PTC behavior and results in a trip-state control current flow to said control current collecting layer before any other elements of a circuit including the device reach a damaging overheating temperature.