Device for protection from overvoltages
AssigneeCitel
InventorsVincent CREVENAT, Cyril ROUSSEAUX
Life of this patent
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Abstract
An overvoltage protection device having a printed circuit board, a varistor having a metal-oxide varistor body that has a face and a conductive metal layer deposited on the face where the varistor is connected to a first electrical connection terminal by a first connection track of the printed circuit board and a disconnection tab is disclosed. The disconnection tab being fastened directly to the metal layer by a thermofusible link and exerting a traction force on the metal layer so that the disconnection tab moves away from the metal layer and disconnects the electrical connection between the first terminal and the varistor in response to melting of the thermofusible link is also disclosed.
Claims13
An overvoltage protection device (1) comprising:
- a printed circuit board (9),
- a varistor (21) having a metal-oxide varistor body that has a face (25) and a conductive metal layer (28) deposited on said face (25),
- wherein the varistor (21) is connected to a first electrical connection terminal (2) by a first connection track (10) of the printed circuit board and a disconnection tab (24), the disconnection tab (24) being fastened directly to the metal layer (28) by a thermofusible link and exerting a traction force on said metal layer (28) such that the disconnection tab (24) moves away from the metal layer (28) and disconnects the electrical connection between the first terminal (2) and the varistor (21) in response to melting of the thermofusible link,
- wherein the metal layer (28) has a thickness of between 8 μm and 16 μm,
- wherein the disconnection tab (24) is a leaf spring that is prestressed by the thermofusible link between an end (34) of said leaf spring and the conductive metal layer (28), and
- wherein the prestressing force applied to the disconnection tab (24) and maintained by the thermofusible link is between 5 N and 10 N.
(canceled)
6-7 (canceled)
A method for manufacturing an overvoltage protection device, comprising:
- providing a printed circuit board (9) comprising a plurality of electrical connection terminals (2, 3, 4, 5, 6) and a plurality of conductive tracks (10, 12, 14, 16, 18, 19),
- providing a varistor (21) having a metal-oxide varistor body which has a face (25) and a conductive metal layer (28) deposited on said face (25),
- fastening a disconnection tab (24) to a first track (10) of the printed circuit board (9), said first track (10) connecting said disconnection tab (24) and a first electrical connection terminal (2), a tab to be soldered being arranged between the disconnection tab and the first track (10),
- fastening the varistor (21) to the printed circuit board (9) so that an end of the disconnection tab (24) opposite the first track (10) is located facing and at a distance from the first metal layer (28) of the varistor (21), a tab to be soldered being arranged between the varistor (21) and the printed circuit board (9),
- elastically deforming the disconnection tab (24) so as to bring the second end of said disconnection tab (24) into contact with the metal layer (28), and
- carrying out thermofusible soldering between said end of the disconnection tab (24) and the metal layer (28),
- wherein the metal layer (28) has a thickness of between 8 μm and 16 μm,
- wherein the disconnection tab (24) is a leaf spring that is prestressed by the thermofusible link between an end (34) of said leaf spring and the conductive metal layer (28), and
- wherein the prestressing force applied to the disconnection tab (24) and maintained by the thermofusible link is between 5 N and 10 N.
13-14 (canceled)
Dependencies are inferred from the claim text.