Transient voltage protection circuit boards and manufacturing methods

A transient voltage suppression circuit board, comprising:

• a laminated circuit board structure for mounting of a plurality of electronic components, the laminated structure comprising:
• a dielectric substrate layer defining a first major surface, a second major surface, and a plurality of spaced holes arranged in an array, the holes extending between the first major surface and the second major surface, each of the holes defining a receptacle for a variable impedance material;
• a ground plane in direct contact with the second major surface of the dielectric substrate layer;
• a variable impedance material substantially filling each of the plurality of holes in the substrate, wherein the variable impedance material exhibits a relatively high impedance when subjected to voltage and/or current up to a predetermined threshold value, and exhibits a relatively low impedance when subjected to voltage and/or current that exceeds the predetermined threshold, the variable impedance material defining a shunt current path through the holes to the ground plane when exhibiting the low impedance;
• a transmission layer applied to the first major surface, the transmission layer being electrically conductive in a direction normal to the first major surface, and insulative in the plane of the first major surface;
• and a circuit layer formed directly on the transmission layer.

A circuit board having embedded transient voltage suppression, the circuit board comprising:

• a circuit board structure for electrically connecting a plurality of electrical components, the structure comprising:
• a dielectric substrate layer fabricated from a polyimide material, the substrate layer defining a first major surface, a second major surface, and a plurality of holes extending therethrough, each of the holes defining a receptacle for a variable impedance material;
• a variable impedance material substantially filling each of the plurality of holes in the substrate, wherein the variable impedance material exhibits a relatively high impedance when subjected to voltage and/or current up to a predetermined threshold value, and exhibits a relatively low impedance when subjected to voltage and/or current that exceeds the predetermined threshold, the variable impedance material defining a shunt current path through the holes to the ground plane when exhibiting the low impedance;
• a transmission layer extending over the first major surface and directly contacting the variable impedance material on the first major surface, the transmission layer being electrically conductive in a direction normal to the first major surface, and insulative in the plane of the first major surface;
• a circuit layer formed on the transmission layer and
• a ground plane laminated to the second major surface of the dielectric substrate layer and directly contacting the variable impedance material on the second major surface.

A method of fabricating a circuit board, the method comprising:

• providing a dielectric substrate layer having an array of holes formed therethrough;
• filling the holes with a variable impedance material;
• attaching a transmission layer to the substrate layer, the transmission layer being electrically conductive in a direction normal to the substrate layer and insulative in a plane parallel to the substrate layer;
• forming a circuit pattern directly on the transmission layer, the circuit pattern being configured to mount and electrically connect a plurality of electrical components,
• thereby establishing a shunt current path between the circuit pattern and the variable impedance material via the transmission layer.

A circuit board comprising:

• a dielectric substrate;
• means for connecting to electrical ground, the means for connecting coupled to the substrate;
• means for defining a circuit pattern coupled to the substrate for connection of a plurality of electrical components, the means for defining the circuit pattern coupled to the substrate opposite the means for connecting to electrical ground;
• variable impedance means, situated in the dielectric substrate, for establishing a plurality of shunt currents paths between the means for defining the circuit pattern and the means for connecting to electrical ground in response transient high voltage events;
• and
• transmission means for conducting shunt current from the circuit pattern to the variable impedance means, without shorting of adjacent shunt current paths;
• wherein the means for defining a circuit pattern are formed on the transmission means.