SYSTEM AND METHOD FOR GAPPING AN EMBEDDED MAGNETIC DEVICE
Disclosed is an apparatus and method for a magnetic component. The method of an example embodiment includes: forming a feature on a substrate, the feature being a depression defining an inside surface; disposing a first conductive pattern on the substrate and the inside surface of the feature; disposing a permeability material on the inside surface of the feature and the first conductive pattern; disposing a substrate material on the substrate and the feature; disposing a second conductive pattern on the substrate material, the second conductive pattern substantially matching the first conductive pattern to wrap the permeability material between the first conductive pattern and the second conductive pattern producing a winding type structure electrically coupling the first conductive pattern and the second conductive pattern in electrical connection to define at least one electrical circuit to facilitate a magnetic field in the permeability material; and gapping the permeability material to remove at least a portion of the permeability material to produce a gap in the at least a portion of the permeability material.
This is a divisional patent application claiming priority to U.S. patent application Ser. No. 15/168,185, filed on May 30, 2016; which is a continuation-in-part patent application claiming priority to U.S. patent application Ser. No. 12/329,887, filed on Dec. 8, 2008, which is a divisional application claiming priority to U.S. non-provisional patent application Ser. No. 11/233,824, filed on Sep. 22, 2005, which are in their entirety incorporated herein by reference.
BACKGROUNDThe disclosure generally relates to magnetic components.
A wide range of electronic devices may have various magnetic components. Magnetic components may be capable of providing various functions. For example, magnetic components in electronic devices may function as transformers, inductors, filters, and so forth. Commonly, in order to have magnetic properties, magnetic components may comprise of an assembly of one or more wires wound around a material having permeability properties such as ferromagnetic material having a toroidal type shape, a rod type shape, etc. When a current is applied to the one or more wires, the component may produce a magnetic field, which may be utilized to address a wide range of electrical needs associated with electronic devices.
Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which like references may indicate similar elements and in which:
In the following description, embodiments will be disclosed. For purposes of explanation, specific numbers, materials, and/or configurations are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to those skilled in the art that the embodiments may be practiced without one or more of the specific details, or with other approaches, materials, components, etc. In other instances, well-known structures, materials, and/or operations are not shown and/or described in detail to avoid obscuring the embodiments. Accordingly, in some instances, features are omitted and/or simplified in order to not obscure the disclosed embodiments. Furthermore, it is understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.
References throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, material, and/or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” and/or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, materials, and/or characteristics may be combined in any suitable manner in one or more embodiments.
For the purposes of the subject matter disclosed herein, substrates may include a wide range of substrates such as, but not limited to, plastic type substrates, semiconductor type substrates, and other insulating material substrates, including polyimide, fiberglass, and ceramic. Accordingly, it should appreciated by those skilled in the art that types of substrates may vary widely based at least in part on its application. However, for the purposes of describing the subject matter, references may be made to a substrate along with some example types, but the subject matter is not limited to a type of substrate. Additionally, for the purposes of describing various embodiments, references may be made to magnetic components. However, it should be appreciated by those skilled in the relevant art that magnetic components may include a wide variety of magnetic components such as, but not limited to transformer type components, inductor type components, filter type components, and so forth, and accordingly, the claimed subject matter is not limited in scope in these respects.
Turning now to the figures,
It should be appreciated that
Continuing to refer to
In
A variety of approaches may be utilized in order to facilitate formation of feature 106. For example, in one embodiment, feature 106 may be formed by utilizing a lithography type process such as, but not limited to photolithography. In another embodiment, feature 106 may be formed by utilizing a machining type process such as, but not limited to, a micromachining process. Various approaches may be utilized to facilitate formation of a feature, and accordingly, the claimed subject matter is not limited to a particular approach.
As shown in
First conductive pattern 108 may comprise of a wide variety of materials such as, but not limited to, copper, aluminum, gold, and various types of conductive tracing materials. Accordingly, the claimed subject matter is not limited in scope in these respects. Continuing to refer to
Permeability material 110 may comprise of a wide variety of materials such as, but not limited to, ferromagnetic type materials that may include ferrite type materials, iron type material, metal type materials, metal alloy type materials, and so forth. Additionally, permeability material 110 may comprise of materials based at least in part on the particular utilization of a magnetic component. For example, a magnetic component to be utilized as an isolation transformer may include a permeability material having a relatively high permeability, such as, but not limited to 10000 Henry per meter. In another example, a magnetic component to be utilized as a common mode filter may include a permeability material having a moderate permeability such as, but not limited to, 1000 Henry per meter. Further, as previously alluded to, the size and shape of the permeability material 110 may be based at least in part on the utilization of the magnetic component as well. Accordingly, the claimed subject matter is not limited in scope in these respects.
In
In the embodiment illustrated in
In the embodiment of
As previously described, once the conductive pattern 306 is disposed on the feature 304, a permeability material may be disposed within the feature 304. A substrate material may be disposed on the surface 302 having a second conductive pattern. Various conductive paths such as, but not limited to, vias and/or interconnects (not shown) may be formed and utilized to electrically couple the two conductive patterns, thereby forming a winding type structure around a permeability material.
Here again, various approaches may be utilized for disposing conductive patterns. For example, one such approach may be a lithography type approach utilizing various etching methods, and another approach may be to utilize a stamping type approach, a laser structuring type approach, and so forth. Conductive patterns may be patterned to facilitate various magnetic properties for various magnetic components based at least in part on their applications. Further, because an approach that may be utilized in providing the number of conductive patterns may be of a lithography type approach, laser structuring type approach, etc., precision of the conductive patterns may be relatively high based at least in part on the type approaches utilized such as, but not limited to, a high aspect lithography approach of ultraviolet photolithography, and accordingly, the claimed subject matter is not limited to a particular approach.
In various embodiments, one or more magnetic components may be formed on a single substrate. Additionally, because the magnetic properties of a magnetic component may be based at least in part on its conductive pattern, its feature size, permeability material utilized, and/or so forth, more than a single type of magnetic component may be formed from a single substrate, and accordingly, the claimed subject matter is not limited in these respects.
Examples of magnetic components may include a magnetic component including a substrate having a feature, a first conductive pattern, a permeability material, a substrate material, and a second conductive pattern, where the first conductive pattern and the second conductive pattern cooperate to be capable of facilitating magnetic properties of the permeability material for various applications. Various applications may include applications such as, but not limited to a dual common mode filter, a single common mode filter, a single inductor, an isolation transformer, and so forth, and accordingly, the claimed subject matter is not limited in these respects. Various embodiments of various magnetic components, without limitations, may be illustrated in
Turning now to
Switch mode power conversion (SMPC) is widely used to implement high efficiency Alternating Current (AC)-to-Direct Current (DC) and DC-to-DC converters. Inductors and transformers are used in SMPC applications for energy storage and to filter switching noise. In most applications, the current in the inductive windings will have both an AC and DC component. Inductors are often implemented by winding a conductive coil around a ferromagnetic core. The amount of inductance is dependent on the number of windings and permeability of the core. When an electric current is applied to the windings, a magnetic field (H) will develop around the conductive windings and induce a magnetic flux (B) in the ferromagnetic core material. The H field is proportional to the driving current and the B field is proportional to the applied voltage. At low current and voltage levels, H and B have a linear relationship. Magnetic saturation occurs when excessive amounts of current are applied and the H field increases to the point where the relationship between H and B is no longer linear. When the core material saturates, the magnitude of the flux density, B, levels off and increasing the magnetic H field will not induce additional magnetic flux. If excessive current is driven into the core, it will saturate and not be able to sustain larger voltages. In the case of an output filter in a power converter, excessive DC current will cause ferromagnetic material to saturate, degrade the inductance, and change the filter performance characteristics.
Transformers are primarily intended to be used as AC devices. Switching the winding current in both a positive and negative direction will effectively switch the direction that the magnetic flux flows within the core material. If switched at high frequencies, the induced fluxes cancel out within each duty cycle. As noted earlier, however, the output of a power converter can have both AC and DC current components. DC current flowing through the output windings of the power transformer can saturate the ferromagnetic core and minimize its ability to store energy and filter noise.
For toroid (ring) shaped cores, designers often cut a gap (slot) out of the core (denoted herein as gapping) to extend its ability to handle DC currents. The gap effectively adds reluctance (resistance to the flow of magnetic flux) to the ferromagnetic core and reduces the sensitivity of the core to the driving current and the associated H field. The core permeability and inductance is reduced dramatically, yet the gapping allows the core to operate with much higher currents before saturation occurs. In the case of the power inductor, gapping allows the inductor to pass DC current to the load, while still serving as a filter to AC currents and high frequency switching noise.
Inductors and transformers come in many shapes and sizes.
Winding solenoids can be automated. Historically, it has been easier to manufacture inductors and transformers on solenoid bobbins rather than on toroid shaped cores. While there are automated winding machines designed to handle large toroid cores (<10 mm diameter), winding wire on a small toroid has defied automation. Plus, machining a gap into a small core requires precision fixtures to hold the core while it is being cut with either a diamond saw or laser. Once the core is gapped, the cut adds complications when applying the wire windings, whether it is wound manually or automatically.
An Example Embodiment for Gapping an Embedded Magnetic DeviceEmbedded magnetic construction gets around the challenges of gapping and winding. Rather than wind wire around the ring structure, the toroid cores in an example embodiment are embedded into a substrate and the windings are applied using standard Printed Circuit Board (PCB) processes. Multiple devices can be arrayed into a panel format and produced in an automated and batch process. Once the inductor or transformer is implemented in the PCB format, it can be easily handled on a machining station. In the case of mechanical gap cutting with a band saw, diamond wheel or cutting device, the panel can first be segmented into 1×N arrays of devices. In that smaller format, the 1xN arrays can be fastened to an x-y machining station and gaps can be cut into the edge of each device. If laser or water jet milling is employed, the panel array can be left intact and the cutting can be applied from either the top, bottom or both surfaces. Laser cutting is preferred in that it can provide narrow and precision gaps into the PCB and ferromagnetic core. The cutting section of the embedded magnetic device is a composite of the substrate material, encapsulation material and the ferromagnetic material. Each of these materials has different machining properties, so some test and experimentation is required to optimize the cut. With a laser, there are a number of variables that can be used to control the width and speed of the cut. These variables include, yet are not limited to; beam wavelength, beam power, beam width/aperture, beam pulse width (rate), and feed rate. The objective is to simply cut the gap into the ferromagnetic core. Yet, the cutting path should extend a small distance beyond the inner and outer radius of the ferromagnetic core, to compensate for any positioning tolerances.
The various embodiments disclosed herein are primarily described with toroid shaped core structures. However, the various embodiments disclosed herein also apply to other shapes of core structures. Other shapes can include an oval, rectangle, and multi-hole core structures.
There may be some applications where it is not necessary to cut the ferromagnetic core all the way through. An example is when it is simply desired to trim or tune the inductance value. In this instance, the laser or cutting tool would only cut into a fraction of the width of the ferromagnetic core. Here, it is beneficial to monitor the inductance or other electrical characteristics of the embedded magnetic device during the cutting process and use the inductance value or other monitored electrical characteristics to control the cutting tool.
After the gap is applied, it may be beneficial to remove any debris from the gap. This can be achieved with forced air, forced water, forced solvent or by ultrasonic cleaning methods. Chemical and plasma etching may also be employed to remove debris from the gap. In most PCB applications, a solder mask or conformal coating is applied to the top and bottom surfaces to provide voltage isolation and environmental protection. For the same reasons, it is beneficial to fill or coat the applied gap. This can be achieved by filling or coating the gap with epoxy, polyimide or another gap filling material. The fill or coating material can be applied by spaying, painting, screen printing, sputtering, or other suitable method.
Many embedded magnetic inductive devices can be implemented with two printed circuit layers. There will be some instances where more layers are required. For a power transformer, it is useful to put the primary windings on the inner layers and secondary windings on outer layers. When more than two layers are applied, it is best to cut the gap before applying the outer layers. Prior to applying the outer layers, the gap can be filled with epoxy, polymer or other gap filling materials, as described above. An alternative is to simply leave the gap open and simply let the gap fill with epoxy during the lamination of the outer layers.
In various example embodiments, the gap can be applied at different stages of the fabrication process flow. For mechanical gapping, it is typically best to machine the gap after the device fabrication is complete. For laser, water jet, or plasma gapping, the gap can be applied at various stages of the fabrication process.
While there has been illustrated and/or described what are presently considered to be example embodiments of claimed subject matter, it will be understood by those of ordinary skill in the art that various other modifications may be made, and/or equivalents may be substituted, without departing from the true scope of claimed subject matter. Additionally, many modifications may be made to adapt a particular situation to the teachings of claimed subject matter without departing from subject matter that is claimed. Therefore, it is intended that the patent not be limited to the particular embodiments disclosed, but that it covers all embodiments falling within the scope of the appended claims.
Claims
1. An embedded magnetic device comprising:
- a feature formed on a substrate, the feature being a depression defining an inside surface, the feature having a first conductive pattern disposed on the substrate and the inside surface of the feature;
- permeability material disposed on the inside surface of the feature and the first conductive pattern;
- substrate material disposed on the substrate and the feature;
- a second conductive pattern disposed on the substrate material, the second conductive pattern substantially matching the first conductive pattern to wrap the permeability material between the first conductive pattern and the second conductive pattern producing a winding type structure electrically coupling the first conductive pattern and the second conductive pattern in electrical connection to define at least one electrical circuit to facilitate a magnetic field in the permeability material; and
- a gap in at least a portion of the permeability material.
2. The embedded magnetic device of claim 1, wherein the at least one electrical circuit defines at least two interleaved electrical paths to produce a single inductor type functionality.
3. The embedded magnetic device of claim 1, wherein the at least one electrical circuit defines at least two interleaved electrical paths to produce a transformer type functionality.
4. The embedded magnetic device of claim 1, further including a power converter embedded into the substrate.
5. The embedded magnetic device of claim 1 wherein the permeability material is a ferromagnetic core disposed into the substrate and encapsulated and the gap is applied after encapsulation and prior to disposing subsequent substrate layers and conductive patterns.
6. The embedded magnetic device of claim 1 wherein the gap is applied after the first and second substrate layers and conductive patterns are applied.
7. The embedded magnetic device of claim 1 wherein the inductance of the embedded magnetic device is trimmed or tuned while the inductance is monitored in real-time.
8. The embedded magnetic device of claim 1 wherein the gap is cut from both a top surface and a bottom surface of the substrate.
9. The embedded magnetic device of claim 1 being configured as a gapped embedded inductor integrated with a power converter on a printed circuit board (PCB).
10. The embedded magnetic device of claim 1 being configured as a gapped embedded inductor of a power converter module having substrate material disposed upon first and second conductive layers and a third and fourth conductive pattern disposed on the substrate material where conductive circuitry is disposed to receive additional passive and active devices.
11. The embedded magnetic device of claim 1 being configured as a gapped embedded transformer of a power converter module having substrate material disposed upon first and second conductive layers and a third and fourth conductive pattern disposed on the substrate material where conductive circuitry is disposed to receive additional passive and active devices, the third and fourth conductive pattern serving as a printed circuit board (PCB) upon which other passive and active devices are disposed.
12. The embedded magnetic device of claim 1 where the gap is a laser cut having a width based on laser power, laser beam width, position of laser focus, feed rate, pulse rate, and pulse duty cycle.
13. The embedded magnetic device of claim 1 where the permeability material is a ferromagnetic core having a multi-hole core structure and either an oval or square shape.
14. An embedded magnetic device comprising:
- a feature formed on a substrate, the feature being a depression defining an inside surface, the feature having a first conductive pattern disposed on the substrate and the inside surface of the feature;
- permeability material disposed on the inside surface of the feature and the first conductive pattern;
- substrate material disposed on the substrate and the feature;
- a second conductive pattern disposed on the substrate material, the second conductive pattern substantially matching the first conductive pattern to wrap the permeability material between the first conductive pattern and the second conductive pattern producing a winding type structure electrically coupling the first conductive pattern and the second conductive pattern in electrical connection to define at least one electrical circuit to facilitate a magnetic field in the permeability material;
- a gap in at least a portion of the permeability material;
- the substrate material disposed upon the second conductive pattern; and
- a third and fourth conductive pattern disposed on the substrate material, the third and fourth conductive pattern wrapping the permeability material producing a winding type structure electrically coupling the third and fourth conductive patterns in electrical connection to define at least one electrical circuit to facilitate a magnetic field in the permeability material.
15. The embedded magnetic device of claim 14 being configured as a gapped embedded inductor and a printed circuit board (PCB).
16. The embedded magnetic device of claim 14 being configured as gapped embedded transformer and a printed circuit board (PCB).
17. The embedded magnetic device of claim 14, wherein the gap is cleaned with forced air, forced water, or ultrasonic cleaning to eliminate debris.
18. The embedded magnetic device of claim 14, wherein the gap is filled with epoxy, solder mask, polyimide, pre-preg, or gap filling material.
19. The embedded magnetic device of claim 14, wherein the gap is filled with epoxy, solder mask, polyimide, pre-preg, or gap filling material when the substrate material is disposed on the substrate.
20. The embedded magnetic device of claim 14 where the permeability material is a ferromagnetic core having a multi-hole core structure and either an oval or square shape.
21. The embedded magnetic device of claim 14 including a marking on a top or bottom surface to provide a target and facilitate laser set-up, step, and repeat cutting.
Type: Application
Filed: Jun 23, 2018
Publication Date: Dec 20, 2018
Inventor: James E. Quilici (El Dorado Hills, CA)
Application Number: 16/016,576