The subject matter described and/or illustrated herein relates generally to power supplies for supplying electrical power to electrical systems.
Power supplies that supply electrical power to electronic systems are being designed to have greater power capacity (e.g., supply more electrical wattage) to accommodate the increased electrical power consumption of contemporary electronic systems. For example, power bus bars have been used with interconnect devices (e.g., electrical connectors and/or the like) that interconnect the power supply to the associated electronic system to handle the larger current load supplied by the power supply. But, at least some known interconnect devices for power supplies may be susceptible to overcurrent situations, which may damage and/or cause one or more components of the electronic system to fail. For example, an overcurrent situation may burn up a line card that is being supplied with electrical power by a known interconnect device that does not have the capability to break the circuit between the power supply and the line card when the overcurrent situation occurs. Specifically, a sufficient amount of current may be delivered to the line card to heat the line card to failure (e.g., by fracturing) from the mechanical stresses resulting from the increased temperature and/or the resulting thermal contraction of subsequent cooling.
In an embodiment, an electrical power contact includes a mating segment having a mating interface at which the electrical power contact is configured to mate with a mating contact. The mating segment includes an electrically conductive base layer, and an electrically conductive outer layer that includes the mating interface. The mating segment also includes a circuit protection layer that extends between the base layer and the outer layer. The circuit protection layer provides an electrical pathway between the base layer and the outer layer. The circuit protection layer includes a selectively conductive material that is configured to open the electrical pathway between the base layer and the outer layer when an electrical current above a predetermined threshold is passed through the circuit protection layer.
In an embodiment, an electrical power contact includes a mating segment having a mating interface at which the electrical power contact is configured to mate with a mating contact. The mating segment includes an electrically conductive base layer, and an electrically conductive outer layer that includes the mating interface. The mating segment also includes a polymeric positive temperature coefficient (PPTC) layer that extends between the base layer and the outer layer. The PPTC layer provides an electrical pathway between the base layer and the outer layer. The PPTC layer is configured to open the electrical pathway between the base layer and the outer layer when an electrical current above a predetermined threshold is passed through the PPTC layer.
In an embodiment, an electrical power connector includes an electrical power contact having a mating segment that includes a mating interface at which the electrical power contact is configured to mate with a mating contact. The mating segment includes an electrically conductive base layer, and an electrically conductive outer layer that includes the mating interface. The mating segment also includes a circuit protection layer that extends between the base layer and the outer layer. The circuit protection layer provides an electrical pathway between the base layer and the outer layer. The circuit protection layer includes a selectively conductive material that is configured to open the electrical pathway between the base layer and the outer layer when an electrical current above a predetermined threshold is passed through the circuit protection layer.
The power supply 14 may be any type of electrical power supply having any components, structure, and/or the like. In the illustrated embodiment, the power supply 14 includes a printed circuit board 24. The power connector 16 of the power supply 14 is fixed in position on the circuit board 24 in the illustrated embodiment. But, in other embodiments, the power connector 16 floats relative to the printed circuit board 24. In addition or alternative to the printed circuit board 24, the power supply 14 may include one or more electrical wires (not shown) and/or other components (not shown). The power supply 14 may include any number of the power connectors 16 for mating with the electronic system 12. As shown herein, the power supply 14 includes a single power connector 16 and the electronic system 12 includes two power connectors 18. But, the electronic system 12 may include any number of power connectors 18 for mating with any number of power supplies 14.
In the illustrated embodiment, the electronic system 12 includes a backplane 26, a power bus bar assembly 28 mounted to the backplane 26, and one or more of the power connectors 18. The electronic system 12 also includes other components that are not shown herein for clarity. Such other components of the electronic system 12 that are not shown herein may include, but are not limited to, processing components, storage components, display components, and/or the like. The electronic system 12 may be any type of electronic system, such as, but not limited to, a line card, a motherboard, a processing unit, and/or the like. Optionally, the electronic system 12 includes one or more signal connectors (not shown), and/or one or more of the power connectors 18 includes signal contact(s), for transmitting signals between the electronic system 12 and another component (not shown). In some embodiments, the electronic system 12 includes one or more power connectors (not shown) that mate with one or more corresponding power connectors (not shown) of the power supply 14 to provide an electrical power input to the power supply 14 (i.e., supply electrical power to the power supply 14).
In the illustrated embodiment, the bus bar assembly 28 includes four layers that are stacked against each other, as can be seen in
The power contacts 32 include mounting segments 40 for mounting the power connector 16 to the printed circuit board 24 (shown in
The power contacts 32 include mating segments 42 for mating with corresponding electrical power contacts 44 (shown in
Although shown as including four power contacts 32, the power connector 16 may include any number of the power contacts 32. As can be seen in
A circuit protection layer 58 extends between the base layer 54 and the outer layer 56. In other words, the circuit protection layer 58 is sandwiched between the outer layer 56 and the base layer 54. The circuit protection layer 58 provides an electrical pathway between the base layer 54 and the outer layer 56. Specifically, the circuit protection layer 58 includes a selectively conductive material (i.e., a material that can change between an electrically conductive state and an electrically conductive state) that is engaged in physical contact between the outer layer 56 and the base layer 54. When the selectively conductive material is in an electrically conductive state, the physical contact of the circuit protection layer 58 with the base layer 54 and the outer layer 56 enables the circuit protection layer 58 to pass electrical energy between the base layer 54 and the outer layer 56. The electrical pathway between the base layer 54 and the outer layer 56 provided by the circuit protection layer 58 is thus closed when the circuit protection layer 58 is in an electrically conductive state. When the circuit protection layer 58 is in an electrically conductive state, the electrical pathway between the base layer 54 and the outer layer 56 provided by the circuit protection layer 58 is open such that the base layer 54 and the outer layer 56 are not electrically connected together.
As briefly described above, the circuit protection elements (e.g., the circuit protection layer 58) of the power contacts 32a are configured to protect the power supply 14 from overcurrent faults. Specifically, the circuit protection layer 58 is configured to open the electrical pathway between the base layer 54 and the outer layer 56 when an electrical current above a predetermined threshold is passed through the circuit protection layer 58. In other words, when the electrical current passing through the circuit protection layer 58 exceeds the predetermined threshold, the selectively conductive material of the circuit protection layer 58 changes from an electrically conductive state to an electrically conductive state such that the base layer 54 and the outer layer 58 are no longer electrically connected together. The circuit protection layer 58 thus provides overcurrent protection by opening the electrical pathway between the base layer 54 and the outer layer 56 during an overcurrent fault.
In the illustrated embodiment, the selectively conductive material of the circuit protection layer 58 is selectively conductive based on the temperature of the selectively conductive material. In other words, the illustrated embodiment of the selectively conductive material of the circuit protection layer 58 is configured to open the electrical pathway between the base layer 54 and the outer layer 56 when the selectively conductive material is heated to a predetermined temperature threshold. In other embodiments, the circuit protection layer 58 additionally or alternatively may include one or more other types of selectively conductive materials.
The specific type of selectively conductive material of the circuit protection layer 58 that is used in the illustrated embodiment is a polymeric positive temperature coefficient (PPTC) material. A PPTC material is a non-conductive crystalline organic polymer matrix that is loaded with electrically conductive particles such that the material is electrically conductive. Examples of PPTC materials include, but are not limited to, a thermally conductive plastic loaded with carbon black particles, and/or the like. In other embodiments, the circuit protection layer 58 may include one or more other types of selectively conductive materials in addition or alternatively to a selectively conductive material that is selectively conductive based on temperature (such as, but not limited to, a positive temperature coefficient (PTC) material).
The operation of the circuit protection layer 58 will now be described. The PPTC material of the circuit protection layer 58 has a current rating. Specifically, when the circuit protection layer 58 is below a predetermined threshold temperature, the electrical pathway between the base layer 54 and the outer layer 56 provided by the circuit protection layer 58 is closed such that the circuit protection layer 58 is configured to pass a predetermined electrical current (referred to herein as the “hold current”) between the base layer 54 and the outer layer 56 (referred to herein as the “on” state of the circuit protection layer 58). More specifically, when the circuit protection layer 58 is below the predetermined threshold temperature, the PPTC material is in a crystalline state, with the conductive particles forced into regions between crystals forming conductive chains. The PPTC material of the circuit protection layer 58 thus has a relatively small resistance (referred to herein as the “initial resistance”) when the circuit protection layer 58 is below the predetermined threshold temperature such that the circuit protection layer 58 will pass the hold current). Accordingly, when the circuit protection layer 58 is in the on state, the corresponding power contact 32a can carry the hold current between the power supply 14 (shown in
When electrical current flowing through the corresponding power contact 32a, and thus the circuit protection layer 58, exceeds a predetermined current limit (referred to herein as the “trip current”), the circuit protection layer 58 is altered by heat. The polymer of the PPTC material of the circuit protection layer 58 expands as the circuit protection layer 58 is heated by the excess electrical current. Once the PPTC material of the circuit protection layer 58 is heated to the predetermined threshold temperature, the expansion of the PPTC material changes the PPTC material from a crystalline state into an amorphous state. Specifically, the expansion separates the conductive particles of the PPTC material and thereby breaks the conductive pathways of the circuit protection layer 58, which substantially increases (e.g., by two or more orders of magnitude) the resistance of the circuit protection layer 58.
The increased resistance of the circuit protection layer 58 reduces the amount of electrical current carried by the circuit protection layer 58 sufficiently to open the electrical pathway between the base layer 54 and the outer layer 56 (provided by the circuit protection layer 58) such that the circuit protection layer 58 is no longer capable of passing the hold current between the outer layer 56 and the base layer 54 (i.e., the “off” or “tripped” state of the circuit protection layer 58). Accordingly, the PPTC material of the circuit protection layer 58 is configured to open the electrical pathway between the outer layer 56 and the base layer 54 by physically expanding when heated by excess electrical current passing through the circuit protection layer 58.
As should be appreciated from the above description, the corresponding power contact 32a does not carry the hold current between the power supply 14 and the corresponding power connector 18 when the circuit protection layer 58 is in the off state. The circuit protection layer 58 is thus a passive circuit protection element that provides overcurrent protection for the corresponding power contact 32a, and thus for the power supply 14, the corresponding power connectors 16 and 18, and the electronic system 12 (shown in
It should be understood that the circuit protection layer 58 will pass a relatively small amount of electrical current between the base layer 54 and the outer layer 56 when the circuit protection layer 58 is in the off state. The relatively small amount of electrical current carried by the circuit protection layer 58 in the off state may be sufficient to maintain the temperature of the circuit protection layer 58 at a level that is sufficient to maintain the increased resistance of the circuit protection layer 58 (i.e., the circuit protection layer 58 can be considered to have latching functionality).
When the excess electrical current (i.e., the overcurrent fault) is removed from the assembly 10 (shown in
The circuit protection layer 58 may be configured to carry any value(s) of hold current. Moreover, the circuit protection layer 58 be configured with any value(s) of initial resistance. The predetermined threshold temperature selected for the circuit protection layer 58 may have any value(s).
The resistance of the circuit protection layer 58 may increase by any amount sufficient to change the circuit protection layer 58 from the on state to the off state, such as, but not limited to, by one or more orders of magnitude. Moreover, the circuit protection layer 58 may be configured with any value of trip current, such as, but not limited to, from approximately 20 mA to approximately 100 A. The increased resistance of the circuit protection layer 58 (described above) that reduces the amount of electrical current carried by the circuit protection layer 58 sufficiently to open the electrical pathway between the base layer 54 and the outer layer 56 may have any value(s), such as, but not limited to, hundreds of ohms, thousands of ohms, and/or the like.
Various parameters of the circuit protection layer 58 may be selected to provide the circuit protection layer 58 with predetermined physical and electrical properties. Examples of such parameters that may be selected for the circuit protection layer 58 include, but are not limited to, the type(s) of selectively conductive material, the type(s) of PPTC material, the amount of surface area of the base layer 54 of the mating segment 42 that is covered by the circuit protection layer 58, the location(s) along the mating segment 42 of the circuit protection layer 58, the size (e.g., the thickness, the surface area, and/or the like) of the circuit protection layer 58, the shape of the circuit protection layer 58, whether the outer layer 56 includes any perforations (described below), the number, shape, and/or size of perforations within the outer layer 56, and/or the like. Examples of such physical and electrical properties that may be selected for the circuit protection layer 58 include, but are not limited to, the electrical conductivity (e.g., in the on and/or the off state), the hold current, the initial resistance, the predetermined threshold temperature, the amount the resistance of the circuit protection layer 58 increases when the circuit protection layer 58 changes from the on state to the off state, the trip current, the resistance in the off state, the rate and/or amount of physical expansion as the circuit protection layer 58 rises in temperature, the thermal conductivity, a reset time, and/or the like. The circuit protection layer 58 may cover any amount, and have any location(s) along, the base layer 54 of the mating segment 42.
The outer layer 56 may be fabricated from any material(s) that provide the outer layer 56 as sufficiently electrically conductive to carry the hold current. In some embodiments, the outer layer 56 includes an abrasion resistant material. The outer layer 56 optionally is perforated (not shown), for example to accommodate and/or facilitate the temperature increase of the circuit protection layer 58 during an overcurrent fault, to accommodate the physical expansion of the circuit protection layer 58, and/or the like. The outer layer 56 may cover any amount, and have any location(s) along, each of the base layer 54 and the circuit protection layer 58 of the mating segment 42. In some embodiments, the circuit protection layer 58 covers more of the base layer 54 than the outer layer 56, the outer layer 56 covers more of the base layer 54 than the circuit protection layer 58, and/or the outer layer 56 does not cover the approximate entirety of the circuit protection layer 58.
Although two of the power contacts 32 (i.e., the power contacts 32a) are shown as including the circuit protection layer 58 and two of the power contacts 32 (i.e., the power contacts 32b) are shown as not including the circuit protection layer 58, any number of the power contacts 32 may include the circuit protection layer 58. Moreover, any number of the mating segments 42 of each power contact 32 may include the circuit protection layer 58.
Referring again to
The housing 60 is mounted to the backplane 26 such that the housing 60 is indirectly mounted to the bus bar assembly 28, as is shown in
In the illustrated embodiment, the power contacts 44 are defined by projections of the bus bar assembly 28 (i.e., the power contacts 44 are integral extensions of the bus bar assembly 28). In other embodiments, one or more of the power contacts 44 may be a discrete contact that is mounted to the bus bar assembly 28 (i.e., a component that is separate from the bus bar assembly 28 and is mounted thereto). Moreover, in addition or alternatively to being mounted to or defined by the bus bar assembly 28, one or more of the power contacts 44 may be mounted to a printed circuit board (not shown) and/or one or more of the power contacts 44 may terminate one or more electrical wires (not shown).
The power contacts 44 include the mating segments 48 for mating with the corresponding electrical power contacts 32 of the corresponding power connector 16. Each mating segment 48 includes a mating interface 76 (better seen in
Although shown as including four power contacts 44, the power connector 18 may include any number of the power contacts 44. As can be seen in
Specifically, the mating segments 48 include an electrically conductive base layer 84 and an electrically conductive outer layer 86 that extends over the base layer 84, with a circuit protection layer 58 extending between the base layer 84 and the outer layer 86. As shown in
As described above with respect to the power connectors 16 and the electronic system 12, the circuit protection layer 58 includes a selectively conductive material and is configured to protect against overcurrent faults. Specifically, the circuit protection layer 58 is configured to open an electrical pathway between the base layer 84 and the outer layer 86 (provided by the circuit protection layer 58) when an electrical current above the predetermined threshold is passed through the circuit protection layer 58 (i.e., during an overcurrent fault). When the circuit protection layer 58 is in the on state, the corresponding power contact 44 can carry the hold current between the electronic system 12 and the corresponding power connector 16 (shown in
The outer layer 86 may be fabricated from any material(s) that provide the outer layer 86 as sufficiently electrically conductive to carry the hold current. In some embodiments, the outer layer 86 includes an abrasion resistant material. The outer layer 86 optionally is perforated (not shown), for example to accommodate and/or facilitate the temperature increase of the circuit protection layer 58 during an overcurrent fault, to accommodate the physical expansion of the circuit protection layer 58, and/or the like. The outer layer 86 may cover any amount, and have any location(s) along, each of the base layer 54 and the circuit protection layer 58 of the mating segment 48. In some embodiments, the circuit protection layer 58 covers more of the base layer 84 than the outer layer 86, the outer layer 86 covers more of the base layer 84 than the circuit protection layer 58, and/or the outer layer 86 does not cover the approximate entirety of the circuit protection layer 58. Any number of the power contacts 44 may include the circuit protection layer 58. Moreover, any number of the mating segments 48 of each power contact 44 may include the circuit protection layer 58.
As shown in
As can be seen from a comparison of
The mating segments 142 of the power contact 132 include circuit protection elements that are configured to protect against overcurrent faults. Specifically, the mating segments 142 include an electrically conductive base layer 154 and an electrically conductive outer layer 156 that extends over the base layer 154, with a circuit protection layer 58 extending between the base layer 154 and the outer layer 156. As shown in
As described above with respect to the power connector 16 and the power connector 18 (shown in
Although two are shown, the edge portion 134 may define any number of mating segments 142. Each mating segment 142 may have any location along the length L of the edge portion 134 of the bus bar assembly 128. In some embodiments, the edge portion 134 defines a single mating segment 142, regardless of whether the signal mating segment 142 extends along an approximate entirety of a length L of the edge portion 134. Any number of the mating segments 142 may include the circuit protection layer 58. The circuit protection layer 58 of each mating segment 142 may cover any amount of the base layer 154 of the mating segment 142. In some embodiments, the edge portion 134 defines a single mating segment 142 that extends along an approximate entirety of the length L of the edge portion 134.
The outer layer 156 may be fabricated from any material(s) that provide the outer layer 156 as sufficiently electrically conductive to carry the hold current. In some embodiments, the outer layer 156 includes an abrasion resistant material. The outer layer 156 optionally is perforated (not shown), for example to accommodate and/or facilitate the temperature increase of the circuit protection layer 58 during an overcurrent fault, to accommodate the physical expansion of the circuit protection layer 58, and/or the like. The outer layer 156 may cover any amount, and have any location(s) along, each of the length L of the edge portion 134, the base layer 154 of a mating segment 142, and the circuit protection layer 58 of each mating segment 158. In some embodiments, the circuit protection layer 58 covers more of the base layer 154 than the outer layer 156 of one or more mating segments 142, the outer layer 156 covers more of the base layer 84 than the circuit protection layer 58 of one or more mating segments 142, and/or the outer layer 86 does not cover the approximate entirety of the circuit protection layer 58 of one or more mating segments 142.
As shown in
The embodiments described and/or illustrated herein provide an electrical power contact that includes a circuit protection layer that provides protection against overcurrent faults. The embodiments described and/or illustrated herein provide an electrical component (e.g., a contact, a connector, and/or the like) with a passive circuit protection device that does not add an additional circuit to the electrical component and therefore may not increase the size of the electrical component and/or may increase the size of the electrical component less than at least some known active circuit protection devices.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means—plus-function format and are not intended to be interpreted based on 35 U.S.C. §112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.