Controllable fuse

A controllable fuse comprising:

• a) a pair of electrically isolated conductor pads;
• b) at least one solder connection electrically connecting said conductor pads and creating a circuit connection therebetween;
• c) at least one heater element means producing heat in response to the application of an external electrical signal to said heater element means;
• and
• d) an electrically insulating but thermally conducting material provided between said heater element means and said conductor pads, said heater element means thermally conductively coupled through said insulating material t said solder connection such that upon application of said external electrical signal to said heater element means sufficient heat is generated to desolder said solder connection and thereby disconnect said circuit connection between said conductor pads;
• wherein the improvement comprises said conductor pads being provided on a planar surface and said heater element means being provided as a substantially planar film on a planar surface with said insulating material being provided between said heater element means and said conductor pads.
• said fuse including a substrate having at least one of said heater element means and said pair of conductor pads deposited on a first surface of said substrate, and wherein said insulating material comprises a deposited film of electrically insulating dielectric material separating and deposited between said planar heating element means and said conductor pads, with one of said heating element means and said pair of conductor pads deposited on said insulating film.

A method for manufacturing a controllable fuse comprising:

• a) a pair of electrically isolated conductor pads;
• b) at least one solder connection electrically connecting said conductor pads and creating a circuit connection therebetween;
• c) at least one heater element means producing heat in response to the application of an external electrical signal to said heater element;
• and
• d) an electrically insulating but thermally conducting layer of material provided between said heater element means and said conductor pads, said heater element means thermally conducting layer to said solder connection such that upon application of said external electrical signal to said heater element means sufficient heat is generated to desolder said solder connection and thereby disconnect said circuit connection between said conductor pads;
• wherein said method comprises the steps of:
• 1) depositing said conductor pads on a planar surface, and
• 2) depositing said heater element means as a planar film on said thermally conducting layer, said method also including the steps of providing said solder connection between said pads by (a) providing a solder retaining area defined by an applied solder retaining structure which surrounds said solder retaining area, said solder retaining area emcompassing a portion of at lest each of said conductor pads, (b) applying solder within said solder retaining area so as to bridge said conductor pads by a solder connection comprising a solder mass physically and electrically bridging and soldered to said conductor pads, and (c) subsequently removing said solder retaining structure.

A controllable fuse comprising:

• a) a pair of electrically isolated conductor pads;
• b) at least one solder connection electrically connecting said conductor pads and creating a circuit connection therebetween;
• c) at least one heater element means producing heat in response to the application of an external electrical signal to said heater element means;
• and
• d) an electrically insulating but thermally conducting material providing between said heater element means and said conductor pads, said heater element means thermally conductively coupled through said insulating material to said solder connection such that upon application of said external electrical signal to said heater element means sufficient heat is generated to desolder said solder connection and thereby disconnect said circuit connection between said conductor pads;
• wherein the improvement comprises said heater element means comprises two separate heater elements each receiving its own associated separate and independent external electrical signal and each generating heat in response thereto which is coupled through said material to said solder connection, wherein in response to either one of said external electrical signals being applied to its associated heater element said heater element provides sufficient heat to disconnect said circuit connection.

A controllable fuse comprising:

• a) a pair of electrically isolated conductor pads;
• b) at least one solder connection electrically connecting said conductor pads and creating a circuit connection therebetween;
• c) at least one heater element means producing heat in response to the application of an external electrical signal to said heater element means;
• and
• d) an electrically insulating but thermally conducting material provided between said heater element means and said conductor pads, said heater element means thermally conductively coupled through said insulating material to said solder connection such that upon application of said external electrical signal to said heater element means sufficient heat is generated to desolder said solder connection and thereby disconnect said circuit connection between said conductor pads;
• wherein the improvement comprises said heater element means comprises two separate heater elements each receiving its own associated separate and independent external electrical signal and each generating heat in response thereto which is coupled through said material to said solder connection, wherein in response to the application of said external electrical signals to both of said heater elements said heater means provides sufficient heat to disconnect said circuit connection, the heat provided by any one of said heater elements being insufficient to desolder said solder connection and remove said circuit connection.