Electricity: electrothermally or thermally actuated switches – Electrothermally actuated switches – Fusible element actuated
Reexamination Certificate
2000-08-28
2003-01-14
Vortman, Anatoly (Department: 2835)
Electricity: electrothermally or thermally actuated switches
Electrothermally actuated switches
Fusible element actuated
C337S158000, C337S295000, C337S405000, C257S690000
Reexamination Certificate
active
06507264
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a fuse which is integrally-formed within a semiconductor package, to a semiconductor apparatus having both a semiconductor device and a fuse integrally-formed within a semiconductor package, to a method of integrating a fuse into a semiconductor package, and to a method of providing overcurrent and overvoltage protection to a telecommunications circuit.
Fuses long have been used to provide overcurrent protection to a circuit in a wide variety of applications. Fundamental operation of a fuse requires that a typically metallic fuse element open up or break via self-heating upon a predetermined overcurrent condition.
Subminiature fuses, or microfuses, are terms which are known in this field to describe very small fuses that are particularly useful to protect electronic components and circuitry on a printed circuit board. Indeed, as the continued miniaturization of electronic circuits occurs, so too must the miniaturization occur for the associated components—including fuses.
Known microfuses typically have a rigid glass or ceramic tube and a metallic fuse element housed within. Surrounding the fuse element within the tube might be air, gas, or some other arc-suppression filler material. Two respective ends of such fuse element typically extend out from the associated housing such that the fuse may be physically secured to a printed circuit board via the hard wire attachment of these ends to a metallic connection on the printed circuit board. A fuse size, or rating, is typically determined for a particular application whereupon the proper fuse may be attached as a discrete component to the associated printed circuit board.
This discrete component approach, however, requires that the fuse be properly coordinated and matched with the circuitry and components for each particular application so as to satisfy the preferred overcurrent protection criteria. Also, a discretely packaged fuse is typically sourced separately from other components on the printed circuit board, thus adding increased cost to the final product. Furthermore, of course, the more discrete components which are attached to a printed circuit board, the more physical space will be required.
SUMMARY OF THE INVENTION
There is, therefore, a need for an improved semiconductor apparatus which is able to combine both a fuse and at least one semiconductor device in a discrete integral semiconductor package to more easily assure coordination and matching of the fuse and semiconductor devices. In addition, there is a need for such a discrete integral semiconductor package approach which affords lower final product cost and reduces the physical space consumed in a printed circuit.
These and other advantages are provided by the present invention wherein a fuse may be flexibly configured to be integrally-formed with a semiconductor device in a common semiconductor package to form a single discrete circuit element which is, preferably, no larger than the semiconductor package previously known in the art for housing such semiconductor device alone.
Accordingly, in an embodiment of the present invention, a fuse integrally-formed within a unitary semiconductor package is provided which includes: a fuse element; and an encapsulant formed around the fuse element, wherein the fuse may be flexibly configured for the integral formation within the semiconductor package.
In another embodiment of the fuse, the encapsulant is formed of an arc-suppression material.
In another embodiment of the fuse, the fuse element includes first and second ends which remain uncovered from the encapsulant.
In another embodiment of the fuse, the first and second ends connect to portions of a circuit within the semiconductor package.
In another embodiment of the fuse, the fuse is electrically connected to at least one semiconductor device which is integrally-formed within the semiconductor package.
In another embodiment of the fuse, the semiconductor device is an overvoltage protection device.
In another embodiment of the fuse, the semiconductor package has a determined form factor based on the semiconductor device integrally-formed within.
In an alternative embodiment of the present invention, a semiconductor apparatus is provided which includes: a unitary semiconductor package; at least one semiconductor device integrally-formed within the semiconductor package; and a fuse integrally-formed within the semiconductor package.
In another embodiment of the semiconductor apparatus, the fuse is electrically connected to the semiconductor device.
In another embodiment of the semiconductor apparatus, the fuse is made up of a fuse element with an encapsulant formed around the fuse element, the fuse being flexibly configured for the integral formation within the semiconductor package.
In another embodiment of the semiconductor apparatus, the encapsulant is formed of an arc-suppression material.
In another embodiment of the semiconductor apparatus, the fuse element includes first and second ends which remain uncovered from the encapsulant.
In another embodiment of the semiconductor apparatus, the first and second ends connect to portions of a circuit within the semiconductor package, the semiconductor device also being connected to the circuit.
In another embodiment of the semiconductor apparatus, the semiconductor device is an overvoltage protection device.
In another embodiment of the semiconductor apparatus, the semiconductor package has a determined form factor based on the semiconductor device integrally-formed within.
In another alternative embodiment of the present invention, a method is provided of integrating a fuse within a semiconductor package, wherein the method includes the steps of: providing a unitary semiconductor package; providing at least one semiconductor device for integral formation within the semiconductor package; providing a fuse for integral formation within the semiconductor package; and integrally-forming both the semiconductor device and the fuse within the semiconductor package, such that the semiconductor device is electrically connected to the fuse.
In another embodiment of the method of integrating a fuse within a semiconductor package, the method further includes the step of flexibly configuring the fuse to fit within the semiconductor package.
In another embodiment of the method of integrating a fuse within a semiconductor package, the method further includes the step of forming the fuse from a fuse element with an encapsulant formed around the fuse element.
In another embodiment of the method of integrating a fuse within a semiconductor package, the method further includes the step of forming the encapsulant from an arc-suppression material.
In another embodiment of the method of integrating a fuse within a semiconductor package, the semiconductor device is an overvoltage protection device.
In another embodiment of the method of integrating a fuse within a semiconductor package, the method further includes the step of forming the semiconductor package to have a determined form factor based on the semiconductor device integrally-formed therein.
In yet another alternative embodiment of the present invention, a method of providing overcurrent and overvoltage protection to a telecommunications circuit is provided which includes the steps of: providing a semiconductor apparatus having both a fuse and an overvoltage protection device integrally-formed within a semiconductor package; providing a plurality of terminals which are electrically connected to the fuse and the overvoltage protection device, the plurality of terminals protruding out from the semiconductor package; and connecting the plurality of terminals to the telecommunications circuit.
In another embodiment of the method of providing overcurrent and overvoltage protection to a telecommunications circuit, the method further includes the steps of: electrically connecting the fuse between first and second terminals of the plurality of terminals; and electrically connecting the overvoltage protection device between the se
Bell Boyd & Lloyd LLC
Littelfuse Inc.
Vortman Anatoly
LandOfFree
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