Planar magnetic circuit device with reduced PCB layer count

Abstract

A planar magnetic circuit device and method enable a printed circuit board (PCB) of the planar magnetic circuit device to have a reduced PCB layer count. The planar magnetic circuit device comprises a magnetic core and the PCB. The PCB has a cutout region. A first layer of a pair of layers of the PCB includes respective first halves of multiple separate windings that wind around the cutout region via respective turns. A second layer of the pair of layers includes respective second halves of the multiple separate windings. The cutout region contains at least a portion of the magnetic core of the planar magnetic circuit device.

Description

0278.2049001Planar Magnetic Circuit Device with Reduced PCB Layer CountRELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 683,991, filed on August 16, 2024. The entire teachings of the above application are incorporated herein by reference.BACKGROUND

[0002] A planar magnetic circuit is a type of inductive component, such as a transformer or inductor, that utilizes printed circuit board (PCB) technology to create windings, replacing traditional wire windings in a low-profile, planar structure.SUMMARY

[0003] Conventional planar magnetic circuits employ two printed circuit board (PCB) layers for each magnetic circuit winding. Thus, a conventional planar magnetic circuit with multiple windings, such as for a power supply transformer with multiple outputs, utilizes a large number of PCB layers, making the planar magnetic circuit and its associated PCB expensive to produce. An example embodiment implements multiple windings on a minimum number of PCB trace layers. For non-limiting examples, multiple windings may be implemented in a single pair of PCB layers, a multi -tapped winding may be implemented in a single pair of PCB layers, and a center tapped winding may be implemented in a single pair of PCB layers, with exceptional geometric symmetry between the halves of the winding. An example embodiment enables such implementations with a minimum number of PCB layers, namely a single pair of PCB layers of a PCB, because a first layer of the single pair includes respective first halves of multiple separate windings while a second layer of the single pair includes respective second halves of the multiple separate windings as disclosed in further detail below.

[0004] According to an example embodiment, a planar magnetic circuit device comprises a magnetic core and a PCB with a cutout region. A first layer of a pair of layers of the PCB is configured to include respective first halves of multiple separate windings configured to wind around the cutout region via respective turns. A second layer of the pair of layers is configured to include respective second halves of the multiple separate windings. The cutout- 1 -4170643. vl0278.2049001 region is configured to contain at least a portion of the magnetic core of the planar magnetic circuit device.

[0005] The multiple separate windings may be multiple separate conductive traces.

[0006] The magnetic core may include at least one ferromagnetic core.

[0007] The respective first halves of the multiple separate windings of the first layer may be wired to the respective second halves of the multiple separate windings of the second layer via metallic interconnections.

[0008] The cutout region may be a center cutout region located between two other cutout regions of the PCB for non-limiting example. The respective first halves of the multiple separate windings of the first layer may be configured to encircle the center cutout region in a same direction. The same direction may be a clockwise direction or a counterclockwise direction.

[0009] The respective second halves of the multiple separate windings of the second layer may be configured to encircle the center cutout region in a same direction. The same direction may be a clockwise direction or a counterclockwise direction.

[0010] The respective first halves of the multiple separate windings located in the first layer may be configured to spiral outward within the first layer from a bordering region of the first layer toward a peripheral region of the first layer. The bordering region of the first layer may border the cutout region and enable connections between the first layer and other layers of the PCB. The peripheral region of the first layer may enable connections to other PCB circuits, devices, or a combination thereof. The peripheral region may correspond to a periphery of the planar magnetic circuit device.

[0011] The respective second halves of the multiple separate windings located in the second layer may be configured to spiral outward within the second layer from a bordering region of the second layer toward a peripheral region of the second layer. The bordering region of the second layer may border the cutout region and enable connections between the second layer and other layers of the PCB. The peripheral region of the second layer may enable connections to other PCB circuits, devices, or a combination thereof. The peripheral region of the second layer may correspond to a periphery of the planar magnetic circuit device.

[0012] The respective first halves of the multiple separate windings of the first layer and the respective second halves of the multiple separate windings of the second layer may be- 2 -4170643. vl0278.2049001 configured to contribute to magnetic core flux of the planar magnetic circuit device in a same sense.

[0013] The cutout region may be configured to enable a first portion of the magnetic core to mate with a second portion of the magnetic core.

[0014] The pair of layers of the PCB may be a first pair of layers of a plurality of pairs of layers of the PCB. Each pair of layers of the plurality of pairs of layers may be configured to implement multiple respective separate windings that encircle the cutout region.

[0015] The planar magnetic circuit device may be a multi-coil transformer, center-tapped transformer, inductor, or other planar magnetic circuit device.

[0016] According to another example embodiment, a computer-implemented method for implementing a planar magnetic circuit device comprises producing an electronic representation of a PCB of the planar magnetic circuit device. The electronic representation produced includes a cutout region for containing at least a portion of a magnetic core. A first layer of a pair of layers of the PCB in the electronic representation produced includes respective first halves of multiple separate windings that wind around the cutout region via respective turns. A second layer of the pair of layers of the PCB in the electronic representation includes respective second halves of the multiple separate windings. The computer-implemented method further comprises outputting the electronic representation produced toward manufacturing the PCB of the planar magnetic circuit device.

[0017] Further alternative computer-implemented method embodiments parallel those described above in connection with the example planar magnetic device embodiment.

[0018] According to another example embodiment, a non-transitory computer-readable medium for implementing a planar magnetic circuit device may has encoded thereon a sequence of instructions which, when loaded and executed by at least one processor, causes the at least one processor to produce an electronic representation of a PCB of a planar magnetic circuit device. The electronic representation produced includes a cutout region for containing at least a portion of a magnetic core. A first layer of a pair of layers of the PCB in the electronic representation produced includes respective first halves of multiple separate windings winding around the cutout region via respective turns. A second layer of the pair of layers includes respective second halves of the multiple separate windings. The sequence of instructions further causes the at least one processor to output the electronic representation produced toward manufacturing the PCB of the planar magnetic circuit device.- 3 -4170643. vl0278.2049001

[0019] Further alternative non-transitory computer-readable medium embodiments parallel those described above in connection with the example planar magnetic device embodiment.

[0020] According to another example embodiment, a PCB for a planar magnetic circuit device comprises a cutout region, a first layer of a pair of layers, and a second layer of a pair of layers. The first layer of the pair of layers of the PCB is configured to include respective first halves of multiple separate windings. The multiple separate windings are configured to wind around the cutout region via respective turns. The second layer of the pair of layers is configured to include respective second halves of the multiple separate windings. The cutout region is configured to contain at least a portion of the magnetic core of the planar magnetic circuit device.

[0021] Further alternative PCB embodiments parallel those described above in connection with the example planar magnetic device embodiment.

[0022] It should be understood that example embodiments disclosed herein can be implemented in the form of a method, apparatus, system, or computer readable medium with program codes embodied thereon.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0024] The foregoing will be apparent from the following more particular description of example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments.

[0025] FIG. l is a block diagram of an example embodiment of a printed circuit board (PCB) for a planar magnetic circuit device.

[0026] FIG. 2A is an exploded view of an example embodiment of a mechanical assembly.

[0027] FIG. 2B is an assembled view of the mechanical assembly of FIG. 2A.

[0028] FIG. 3 is an illustration of an example embodiment of a planar magnetic circuit device.

[0029] FIG. 4A is an illustration of an example embodiment of conductive traces.- 4 -4170643. vl0278.2049001

[0030] FIG. 4B is an illustration of another example embodiment of conductive traces.

[0031] FIG. 4C is an illustration of an example embodiment of the conductive traces fromFIG. 4A and FIG. 4B wired together.

[0032] FIG. 4D is a schematic symbol for an example embodiment of the windings of FIG. 4C.

[0033] FIG. 5A is an illustration of another example embodiment of conductive traces.

[0034] FIG. 5B is an illustration of another example embodiment of conductive traces.

[0035] FIG. 5C is an illustration of an example embodiment of the conductive traces fromFIG. 5A and FIG. 5B wired together.

[0036] FIG. 5D is a schematic symbol for an example embodiment of the windings of FIG. 5C.

[0037] FIG. 6A is an illustration of another example embodiment of conductive traces.

[0038] FIG. 6B is an illustration of another example embodiment of conductive traces.

[0039] FIG. 6C is an illustration of another example embodiment of conductive traces.

[0040] FIG. 6D is an illustration of another example embodiment of conductive traces.

[0041] FIG. 6E is an illustration of an example embodiment of the conductive traces from FIG. 6A, FIG. 6B, FIG. 6C, and FIG. 6D wired together.

[0042] FIG. 6F is a schematic symbol for an example embodiment of the windings of FIG. 6E.

[0043] FIG. 7A is a three-dimensional illustration of an example embodiment of a transformer with center tapped coils.

[0044] FIG. 7B is an illustration of an example embodiment of conductive traces for the transformer of FIG. 7 A.

[0045] FIG. 7C is an illustration of another example embodiment of conductive traces for the transformer of FIG. 7A.

[0046] FIG. 7D is an illustration of another example embodiment of conductive traces for the transformer of FIG. 7A.

[0047] FIG. 7E is an illustration of another example embodiment of conductive traces for the transformer of FIG. 7A.

[0048] FIG. 7F is an illustration of another example embodiment of conductive traces for the transformer of FIG. 7A.

[0049] FIG. 7G shows the schematic symbol for an example embodiment of the windings of the transformer of FIG. 7A.- 5 -4170643. vl0278.2049001

[0050] FIG. 8 is a flow diagram of an example embodiment of a computer-implemented method for implementing a planar magnetic circuit device.

[0051] FIG. 9 is a block diagram of an example of the internal structure of a computer in which various embodiments of the present disclosure may be implemented.DETAILED DESCRIPTION

[0052] A description of example embodiments follows.

[0053] A layer may be referred to interchangeably herein as a trace layer.

[0054] It should be understood that a shape of a cutout region of a printed circuit board(PCB) disclosed herein is not limited to a shape illustrated in the figures. Further, a shape of a magnetic core disclosed herein is not limited to a shape of a magnetic core illustrated in the figures. It should also be understood that a PCB disclosed herein is not limited to a shape or components illustrated in the figures.

[0055] A winding, as disclosed herein, may be a continuous conducting trace that surrounds magnetic material of a planar magnetic core. A turn, as disclosed herein, is a change in direction.

[0056] Planar magnetic circuits, as they are currently designed, use two printed circuit board PCB trace layers for each magnetic circuit winding. A magnetic circuit with multiple windings, such as for a power supply transformer with multiple outputs, may use a large number of PCB trace layers, making the magnetic circuit, and its associated PCB, more expensive to produce. An example embodiment disclosed herein may use concentric spiral PCB traces to implement multiple windings on a minimum number of PCB trace layers. An example embodiment disclosed herein may be applicable to a multitude of practical magnetic circuit designs, including, but not limited to, multi-coil transformers and coupled inductors, tapped transformer coils and inductors, and center tapped windings for non-limiting examples. According to an example embodiment, multiple windings may be implemented in a single pair of PCB trace layers, such as disclosed below with reference to FIG. 1.

[0057] FIG. 1 is a block diagram of an example embodiment of a PCB 110 for a planar magnetic circuit device (not shown). The PCB 110 comprises a cutout region 102, a first layer 104 of a pair of layers 106, and a second layer 108 of a pair of layers 106. The first layer 104 of the pair of layers 106 of the PCB 110 may be configured to include respective first halves (112a, 112b) of multiple separate windings. The multiple separate windings may be configured to wind around the cutout region 102 via respective turns. The second layer- 6 -4170643. vl0278.2049001108 of the pair of layers 106 may be configured to include respective second halves (not shown) of the multiple separate windings. The cutout region 102 may be configured to contain at least a portion of a magnetic core (not shown) of the planar magnetic circuit device, such as disclosed below with reference to FIG. 2A and FIG. 2B. The pair of layers 106 of the PCB 110 may be a first pair of layers of a plurality of pairs of layers (not shown) of the PCB 110. Each pair of layers of the plurality of pairs of layers may be configured to implement multiple respective separate windings that encircle the cutout region 102. The planar magnetic circuit device may be a multi-coil transformer, center-tapped transformer, inductor, or other planar magnetic circuit device.Example Mechanical Assembly

[0058] FIG. 2A is an exploded view of an example embodiment of a mechanical assembly, namely a PCB 210, with cutout regions (202a, 202b, 202c) configured to accommodate two halves of a magnetic core, namely a first half 212a of the magnetic core and a second half 212b of the magnetic core. A number and location of the cutout regions (202a, 202b, 202c) are for non-limiting example. FIG. 2A shows the parts of a planar magnetic circuit device as implemented in PCB technology. It should be understood that traces (not shown) constituting windings, disclosed further below, may be printed as conductive traces on layers (not shown) of the PCB 210.

[0059] FIG. 2B is an assembled view of an example embodiment of a mechanical assembly for a complete planar magnetic circuit device. With reference to FIGS. 2 A and FIG. 2B, FIG. 2B shows a top view of the mechanical assembly in which a top view of the first half 212a of the magnetic core inserted into the PCB 210 is shown and is mated to the second half 212b (not shown) of the magnetic core via the cutout regions (202a, 202b, 202c) which are, therefore, not shown in FIG. 2B.Example Use Case

[0060] FIG. 3 is an illustration of an example embodiment of planar magnetic circuit device 320, for non-limiting example. The planar magnetic circuit device 320 comprises a magnetic core 322 and a PCB 310 with a cutout region (not shown) The PCB 320 has windings 312 included thereon. Example embodiments of windings of a PCB, such as the PCB 320, are disclosed below.- 7 -4170643. vl0278.2049001Example Multiple Windings

[0061] FIGS. 4A-D show an example embodiment as applied in implementing multiple windings using two PCB trace layers.

[0062] FIG. 4A is an illustration of an example embodiment of conductive traces (412a, 412b, 412c) on one of the PCB trace layers, namely a first layer 404 of a pair of layers of a PCB of a planar magnetic circuit device disclosed herein. The first layer 404 may be referred to as “Layer 1.” The traces (412a, 412b, 412c) of Layer 1 comprise the first halves of 3 concentric spirals for non-limiting example, spiraling in from the periphery 426 of the device, where connections can be made to other PCB circuits and devices, toward the center 429 of the device, where connections can be made to other trace layers included in the planar magnetic device.

[0063] FIG. 4B is an illustration of another example embodiment of conductive traces (414a, 414b, 414c). FIG. 4B shows the conductive traces on a second PCB trace layer, namely a second layer 408, that may be referred to as “Layer 2.” The traces of Layer 2 comprise the second halves of 3 concentric spirals, spiraling out from the center 428 of the device where connections can be made to other trace layers included in the planar magnetic device, to the periphery 426 of the device, where connections can be made to other PCB circuits and devices.

[0064] FIG. 4C is an illustration of an example embodiment of the conductive traces from FIG. 4 A and FIG. 4B wired together in 3 series connections, with plated through holes (412a, 412b, 412c), via feedthroughs, or other metallic interconnections used to connect them.

[0065] It should be appreciated that the traces on first layer 404 (FIG. 4A) and second layer 408 (FIG. 4B) circle the center cutout 402a of the device in the same clockwise direction, so that the traces contribute to magnetic core flux in the same sense. It should also be appreciated that all of the windings implemented in this fashion will reside on two PCB trace layers, rather than the 6 layers that would be required if implemented under the design rules of current art.

[0066] FIG. 4A, FIG. 4B, and FIG. 4C all show the cutouts (402a, 402b, 402c) that may be made in the PCB to allow portions of magnetic cores to be mated together.

[0067] FIG. 4D is a schematic symbol 430 for an example embodiment of the windings of FIG. 4C, as implemented.

[0068] With reference to FIGS. 4A-C, according to an example embodiment, a planar magnetic circuit device may comprise a magnetic core and PCB with a cutout region, as- 8 -4170643. vl0278.2049001 disclosed above. A first layer 404 of a pair of layers of the PCB may be configured to include respective first halves (412a, 412b, 412c) of multiple separate windings configured to wind around the cutout region 402 via respective turns. The cutout region 402 may be configured to contain at least a portion 422 of the magnetic core of the planar magnetic circuit device. The second layer 408 of the pair of layers may be configured to include respective second halves (414a, 414b, 414c) of the multiple separate windings. The multiple separate windings may be multiple separate conductive traces. The magnetic core may include at least one ferromagnetic core.

[0069] The respective first halves (412a, 412b, 412c) of the multiple separate windings of the first layer 404 may be wired to the respective second halves (414a, 414b, 414c) of the multiple separate windings of the second layer 408 via metallic interconnections.

[0070] The cutout region 402a may be a center cutout region located between two other cutout regions (402b, 402c) of the PCB for non-limiting example. The respective first halves (412a, 412b, 412c) of the multiple separate windings of the first layer 404 may be configured to encircle the center cutout region 402a in a same direction. The same direction may be a clockwise direction or a counterclockwise direction.

[0071] The respective second halves (414a, 414b, 414c) of the multiple separate windings of the second layer 408 may be configured to encircle the center cutout region 402a in a same direction. The same direction may be a clockwise direction or a counterclockwise direction.

[0072] The respective first halves (412a, 412b, 412c) of the multiple separate windings located in the first layer 404 may be configured to spiral outward within the first layer 404 from a bordering region of the first layer 404 toward a peripheral region of the first layer 404. The bordering region of the first layer 404 may border the cutout region 402a and enable connections between the first layer 404 and other layers of the PCB. The peripheral region of the first layer 404 may enable connections to other PCB circuits, devices, or a combination thereof. The peripheral region may correspond to a periphery 427 of the planar magnetic circuit device.

[0073] The respective second halves (414a, 414b, 414c) of the multiple separate windings located in the second layer 408 may be configured to spiral outward within the second layer 408 from a bordering region of the second layer 408 toward a peripheral region of the second layer 408. The bordering region of the second layer 408 may border the cutout region 402a and enable connections between the second layer 408 and other layers of the PCB. The peripheral region of the second layer 408 may enable connections to other PCB circuits,- 9 -4170643. vl0278.2049001 devices, or a combination thereof. The peripheral region of the second layer 408 may correspond to a periphery 426 of the planar magnetic circuit device.

[0074] The respective first halves (412a, 412b, 412c) of the multiple separate windings and the respective second halves (414a, 414b, 414c) of the multiple separate windings of the may be configured to contribute to magnetic core flux of the planar magnetic circuit device in a same sense.

[0075] The cutout regions 402a, 402b, 402c may be configured to enable a first portion of the magnetic core to mate with a second portion of the magnetic core, such as the first half 212a and second half 212b of the magnetic core disclosed above with reference to FIG. FIG.2 A and FIG. 2B. Further technical details and examples of multiple separate windings are disclosed below.Tapped Coil

[0076] FIGS. 5A-5D illustrate another example embodiment, as applied in implementing a tapped coil winding using two PCB trace layers.

[0077] FIG. 5A is an illustration of an example embodiment of conductive traces on one of the PCB trace layers, namely a first layer 504. The traces on the first layer 504 comprise the first halves (512a, 512b, 512c) of 3 concentric spirals, spiraling in from the periphery 526 of the device, where connections can be made to other PCB circuits and devices, toward the center 528 of the device, where connections can be made to other trace layers included in the planar magnetic circuit device.

[0078] FIG. 5B is an illustration of another example embodiment of conductive layers. FIG. 5B shows the conductive traces on a second PCB trace layer, namely a second layer 508. The traces on the second layer 508 comprise the second halves (514a, 514b, 5124c) of 3 concentric spirals, spiraling out from the center 528 of the device where connections can be made to other trace layer included in the planar magnetic device, to the periphery 526 of the device, where connections can be made to other PCB circuits and devices.

[0079] FIG. 5C shows the traces from FIG. 5A and 5B wired together in 3 series connections, with plated through holes via feedthroughs or other metallic interconnections used to connect them. With reference to FIGS. 5A-C, the 3 spiral traces on the 2 layers, namely the first layer 504 and the second layer 508, have been mated together at the periphery 526 of the device, with staggered connections so as to implement a series configuration. This results in a single winding with multiple taps. It should be appreciated- 10 -4170643. vl0278.2049001 that the traces on the first layer 504 and the second layer 508 circle the center cutout 502 in the same clockwise direction, so that the traces contribute to magnetic core flux in the same sense.

[0080] It should also be appreciated that all of the windings implemented in this fashion will reside on 2 PCB trace layers, rather than 6 layers as would be employed if implemented under the design rules of current art.

[0081] FIGS. 5A, FIG. 5B, and FIG. 5C all show the cutouts (502a, 502b, 502c) that may be made in the PCB to allow the magnetic planar cores to be mated together.

[0082] FIG. 5D shows the schematic symbol 530 for the windings, as implemented.Center Tapped Coil

[0083] FIGS. 6A-F show another example embodiment, as applied in implementing a transformer winding, center tapped primary and secondary coils, using only 4 PCB trace layers.

[0084] FIG. 6A is an illustration of another example embodiment of conductive traces. FIG. 6 A shows the conductive traces (612a, 612b) on one of the PCB trace layers, namely a first layer 604. The traces on the first layer 604 comprise the first half of 2 concentric spirals, spiraling in from the periphery 626 of a planar magnetic circuit device, where connections can be made to other PCB circuits and devices, toward the center 628 of the planar magnetic circuit device, where connections can be made to other trace layers included in the planar magnetic circuit device.

[0085] FIG. 6B is an illustration of another example embodiment of conductive traces. FIG. 6B shows the conductive traces (614a, 614b) on a second PCB trace layer, namely a second layer 608. The traces on the second layer 608 comprise the second halves of 2 concentric spirals, spiraling out from the center 628 of the planar magnetic circuit device where connections can be made to other trace layer included in the planar magnetic circuit device, to the periphery 626 of the planar magnetic circuit device, where connections can be made to other PCB circuits and devices. The first layer 604 and second layer 608 of FIG. 6A and FIG. 6B, respectively, constitute the transformer’s primary coil winding.

[0086] FIG. 6C is an illustration of another example embodiment of conductive traces. FIG. 6C shows the conductive traces a 3rd PCB trace layers, namely a third layer 634. The traces on the third layer 634 comprise the first half of 2 concentric spirals, spiraling in from the periphery 626 of the planar magnetic circuit device, where connections can be made to- 11 -4170643. vl0278.2049001 other PCB circuits and devices, toward the center 628 of the planar magnetic circuit device, where connections can be made to other trace layers included in the planar magnetic device.

[0087] FIG. 6D is an illustration of another example embodiment of conductive traces. FIG. 6D shows the conductive traces on a 4th PCB trace layer, namely a fourth layer 638. The traces on the fourth layer 638 comprise the second halves of 2 concentric spirals, spiraling out from the center 628 of the planar magnetic circuit device where connections can be made to other trace layer included in the planar magnetic device, to the periphery 626 of the planar magnetic circuit device, where connections can be made to other PCB circuits and devices. The third layer 634 and fourth layer 638 constitute the transformer’s secondary coil winding.

[0088] FIG. 6E is an illustration of an example embodiment of the conductive traces from FIG. 6A, FIG. 6B, FIG. 6C, and FIG. 6D wired together in series connections, with plated through holes, via feedthroughs, or other metallic interconnections used to connect them.The spiral traces on each layer have been mated together near the center 628 of the planar magnetic circuit device, with the outer trace on the first layer 604 connected to the inner trace on the second layer 608, the outer trace on the second layer 608 connected to the inner trace on the first layer 604, the outer trace on the third layer 634 connected to the inner trace on the fourth layer 638, and the outer trace on the fourth layer 638 connected to the inner trace on the third layer 634. The inner traces on the first layer 604 and the second layer 608 are connected together at the periphery 626 of the planar magnetic circuit device; this connection becomes the primary coil’s center tap, with the unconnected ends of the outer traces on the first layer 604 and the second layer 608 becoming the end connection to the primary coil. The inner traces on the third layer 634 and the fourth layer 638 are also connected together at the periphery 626 of the planar magnetic circuit device; this connection becomes the secondary coil’s center tap, with the unconnected ends of the outer traces on the third layer 634 and the fourth layer 638 becoming the end connection to the secondary coil. The center tap and coil ends are all located at the planar magnetic circuit device’s periphery 626 in the example embodiment, allowing direct connection to other PCB circuits and devices.

[0089] It should be appreciated that the traces on the first layer 604, second layer 608, third layer 634, and fourth layer 638 circle the center cutout of the planar magnetic circuit device in the same clockwise direction, so that the traces contribute to magnetic core flux in the same sense. It will also be appreciated that all of the windings implemented in this- 12 -4170643. vl0278.2049001 fashion will reside on only 4 PCB trace layers, rather than 8 layers as would be required if implemented under the design rules of current art.

[0090] It will also be appreciated that the crossed connections between inner and outer traces at the center region of the planar magnetic circuit device allow the windings to exhibit almost perfect geometrical symmetry, limited only by the precision of the PCB fabrication processes, thus reducing a major cause of parasitic leakage inductance.

[0091] FIGS. 6A-E all show the cutouts that may be made in the PCB to allow the planar cores to be mated together.

[0092] FIG. 6F shows the schematic symbol 630 for an example embodiment of the windings, as implemented.

[0093] FIG. 7A is a three-dimensional illustration of an example embodiment of a transformer 750 with center tapped coils.

[0094] FIG. 7B is an illustration of an example embodiment of conductive traces for the transformer 750 of FIG. 7A. The conductive traces 755 are for all PCB trace layers.

[0095] FIG. 7C is an illustration of another example embodiment of conductive traces for the transformer 750 of FIG. 7A. FIG. 7C shows the conductive traces on one of the PCB trace layers, namely a first layer 704.

[0096] FIG. 7D is an illustration of another example embodiment of conductive traces for the transformer 750 of FIG. 7A. FIG. 7D shows the conductive traces on one of the PCB trace layers, namely a second layer 708.

[0097] FIG. 7E is an illustration of another example embodiment of conductive traces for the transformer 750 of FIG. 7A. FIG. 7E shows the conductive traces on one of the PCB trace layers, namely a third layer 734.

[0098] FIG. 7F is an illustration of another example embodiment of conductive traces for the transformer 750 of FIG. 7A. FIG. 7F shows the conductive traces on one of the PCB trace layers, namely a fourth layer 738.

[0099] FIG. 7G shows the schematic symbol 730 for an example embodiment of the windings of the transformer 750 of FIG. 7A.Example Parts and Operation

[0100] An example embodiment may include the following parts (components). For example, (i) planar magnetic cores of a form may be used to mount on a PCB, typically on both sides, top and bottom, of the PCB, so as to confine magnetic flux to fully engage PCB- 13 -4170643. vl0278.2049001 traces encircling elements of the magnetic cores. In addition, (ii) PCB traces on 2 or more layers may be routed in concentric spiral patterns surrounding elements of the magnetic cores. Typically traces on 2 or more layers will be connected to each other to form complete windings. Further, (iii) connections between the PCB traces may be employed on the various layers so as to implement 2 or more complete windings, with options to interconnect said windings to implement taps on one or more composite winding. Additionally, (iv) connections at the centers of the various spiral traces may be used to connect traces from different layers in a series connection, forming complete windings. Further, (v) connections at the periphery of the various spiral traces may be used to connect the device to other components on the PCB, to connect the planar magnetic circuit device’s individual windings together, or both.Example Features

[0101] A non-limiting example of the use of the planar magnetic circuit device’s concentric spiral traces allows multiple transformer or inductor windings to be formed on a pair of PCB trace layers, greatly reducing the expense of producing PCBs using planar magnetic circuits. In a minimal implementation, a complete 2 coil mutual transformer can be implemented using only 2 PCB trace layers, rather than the 4 layers that would be used under existing design rules.Example Manufacturing Techniques

[0102] According to another example embodiment, a planar magnet circuit device may comprise a PCB with a first PCB trace layer including first halves of concentric spiral traces of a magnetic circuit winding with multiple taps. The PCB may further comprise a second PCB trace layer including second halves of the concentric spiral traces of the magnetic circuit winding. The PCB may further comprise interconnections between the first PCB trace layer and second PCB trace layer. The interconnections may be configured to couple the first halves of the concentric spiral traces with the second halves of the concentric spiral traces in a manner that forms the magnetic circuit winding with the multiple taps.

[0103] The first halves of the concentric spiral traces may be configured to spiral, in a common direction, from respective first outer connections at a periphery of the planar magnetic circuit device toward respective first inner connections at a center region of the device. The second halves of the concentric spiral traces may be configured to spiral, in the- 14 -4170643. vl0278.2049001 common direction, from respective second inner connections at the center toward respective second outer connections at the periphery. The interconnections may include buried connections. The buried connections may be configured to couple the respective first inner connections with respective second inner connections to couple the first halves and second halves in series. The interconnections may include staggered connections. The staggered connections may be configured to couple a first subset of the respective first outer connections with a second subset of the respective second outer connections. The multiple taps may correspond to respective first outer connections of the respective first outer connections and respective second outer connections of the respective second outer connections that are not included in the first subset and second subset, respectively.

[0104] An example embodiment disclosed herein can be manufactured using conventional PCB fabrication machinery and techniques. Connections between the windings can be made using customary plated through holes, with blind or buried via holes as an option in designs where space constraints are paramount.

[0105] According to another example embodiment, a multi-tapped winding may be implemented in a single pair of PCB trace layers.

[0106] According to another example embodiment, a center tapped winding may be implemented in a single pair of PCB trace layers, with exceptional geometric symmetry between the halves of the winding.

[0107] A planar magnetic circuit device disclosed herein may comprise one or more ferromagnetic cores inserted into a printed circuit board (PCB), with windings implemented as traces on the PCB. Such a planar magnetic circuit device offers advantages including lower cost, better parameter repeatability, and lower parasitic (leakage) inductance. A computer-implemented method that may produce an electronic representation of the PCB toward manufacturing of same is disclosed below with regard to FIG. 8.

[0108] FIG. 8 is a flow diagram of an example embodiment of a computer-implemented method 800 for implementing a planar magnetic circuit device. The computer-implemented method begins (802) and comprises producing an electronic representation of a PCB of the planar magnetic circuit device (804). The electronic representation produced includes a cutout region for containing at least a portion of a magnetic core. A first layer of a pair of layers of the PCB in the electronic representation produced includes respective first halves of multiple separate windings that wind around the cutout region via respective turns. A second layer of the pair of layers of the PCB in the electronic representation includes respective- 15 -4170643. vl0278.2049001 second halves of the multiple separate windings. The computer-implemented method further comprises outputting the electronic representation produced toward manufacturing the PCB of the planar magnetic circuit device (806). The method thereafter ends (808) in the example embodiment.

[0109] Producing the electronic representation may include wiring the respective first halves of the multiple separate windings of the first layer to the respective second halves of the multiple separate windings of the second layer via metallic interconnections in the electronic representation produced.

[0110] The cutout region may be a center cutout region located between two other cutout regions of the PCB in the electronic representation. Producing the electronic representation may include routing the respective first halves of the multiple separate windings of the first layer to encircle the center cutout region in a same direction. The same direction may a clockwise direction or a counterclockwise direction.

[0111] Producing the electronic representation may include routing the respective second halves of the multiple separate windings of the second layer to encircle the center cutout region in a same direction. The same direction may be a clockwise direction or a counterclockwise direction.

[0112] Producing the electronic representation may include routing the respective first halves of the multiple separate windings to spiral outward within the first layer from a bordering region of the first layer toward a peripheral region of the first layer. The bordering region of the first layer may border the cutout region and enable connections between the first layer and other layers of the PCB. The peripheral region of the first layer may enable connections to other PCB circuits, devices, or a combination thereof. The peripheral region of the first layer may correspond to a periphery of the planar magnetic circuit device.

[0113] Producing the electronic representation may include routing the respective second halves of the multiple separate windings to spiral outward within the second layer from a bordering region of the second layer toward a peripheral region of the second layer. The bordering region of the second layer may border the cutout region and enable connections between the second layer and other layers of the PCB. The peripheral region of the second layer may enable connections to other PCB circuits, devices, or a combination thereof. The peripheral region of the second layer may correspond to a periphery of the planar magnetic circuit device.- 16 -4170643. vl0278.2049001

[0114] Producing the electronic representation may include routing the respective first halves of the multiple separate windings of the first layer and the respective second halves of the multiple separate windings of the second layer in a manner that causes the respective first halves and respective second halves to contribute to magnetic core flux of the planar magnetic circuit device in a same sense.

[0115] The pair of layers of the PCB may be a first pair of layers of a plurality of pairs of layers of the PCB in the electronic representation. Producing the electronic representation may include employing each pair of layers of the plurality of pairs of layers to implement multiple respective separate windings that encircle the cutout region. The computer- implemented method 800 may be implemented via a computer with an internal structure disclosed below with referenced to FIG. 9 for non-limiting example.

[0116] FIG. 9 is a block diagram of an example of an internal structure of a computer 900 in which various embodiments of the present disclosure may be implemented. The computer 900 contains a system bus 905, where a bus is a set of hardware lines used for data transfer among the components of a computer or digital processing system. The system bus 905 is essentially a shared conduit that connects different elements of a computer system (e.g., processor, disk storage, memory, input / output ports, network ports, etc.) that enables the transfer of information between the elements. Coupled to the system bus 905 is an VO device interface 903 for connecting various input and output devices (e.g., keyboard, mouse, display monitors, printers, speakers, microphone, etc.) to the computer 900. A network interface 907 allows the computer 900 to connect to various other devices attached to a network (e.g., global computer network, wide area network, local area network, etc.). Memory 909 provides volatile or non-volatile storage for computer software instructions 911 and data 917 that may be used to implement embodiments (e.g., method 800) of the present disclosure, where the volatile and non-volatile memories are examples of non-transitory media. Disk storage 974 also provides non-volatile storage for the computer software instructions 911 and data 917 that may be used to implement embodiments (e.g, method 800) of the present disclosure. A central processor unit 972 is also coupled to the system bus 905 and provides for the execution of computer instructions.

[0117] Example embodiments disclosed herein may be configured using a computer program product. Further example embodiments may include a non-transitory computer- readable medium that contains instructions that may be executed by a processor, and, when loaded and executed, cause the processor to complete methods described herein.- 17 -4170643. vl0278.2049001

[0118] In addition, the elements described herein may be combined or divided in any manner in software, hardware, or firmware. If implemented in software, the software may be written in any language that can support the example embodiments disclosed herein. The software may be stored in any form of computer readable medium, such as random-access memory (RAM), read-only memory (ROM), compact disk read-only memory (CD-ROM), and so forth.

[0119] The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety.

[0120] While example embodiments have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the embodiments encompassed by the appended claims.- 18 -4170643. vl

Claims

1. 0278.2049001CLAIMSWhat is claimed is:

1. A planar magnetic circuit device comprising: a magnetic core; and a printed circuit board (PCB) with a cutout region, a first layer of a pair of layers of the PCB configured to include respective first halves of multiple separate windings, the multiple separate windings configured to wind around the cutout region via respective turns, a second layer of the pair of layers configured to include respective second halves of the multiple separate windings, the cutout region configured to contain at least a portion of the magnetic core of the planar magnetic circuit device.

2. The planar magnetic circuit device of Claim 1, wherein the multiple separate windings are multiple separate conductive traces.

3. The planar magnetic circuit device of Claim 1, wherein the magnetic core includes at least one ferromagnetic core.

4. The planar magnetic circuit device of Claim 1, wherein the respective first halves of the multiple separate windings of the first layer are wired to the respective second halves of the multiple separate windings of the second layer via metallic interconnections.

5. The planar magnetic circuit device of Claim 1, wherein the cutout region is a center cutout region located between two other cutout regions of the PCB, wherein the respective first halves of the multiple separate windings of the first layer are configured to encircle the center cutout region in a same direction, and wherein the same direction is a clockwise direction or a counterclockwise direction.

6. The planar magnetic circuit device of Claim 1, wherein the cutout region is a center cutout region between two other cutout regions of the PCB, wherein the respective second halves of the multiple separate windings of the second layer are configured to encircle the center cutout region in a same direction, and wherein the same direction is a clockwise direction or a counterclockwise direction.- 19 -4170643. vl0278.20490017. The planar magnetic circuit device of Claim 1, wherein the respective first halves of the multiple separate windings located in the first layer are configured to spiral outward within the first layer from a bordering region of the first layer toward a peripheral region of the first layer, the bordering region bordering the cutout region and enabling connections between the first layer and other layers of the PCB, the peripheral region enabling connections to other PCB circuits, devices, or a combination thereof, the peripheral region corresponding to a periphery of the planar magnetic circuit device.

8. The planar magnetic circuit device of Claim 1, wherein the respective second halves of the multiple separate windings located in the second layer are configured to spiral outward within the second layer from a bordering region of the second layer toward a peripheral region of the second layer, the bordering region bordering the cutout region and enabling connections between the second layer and other layers of the PCB, the peripheral region enabling connections to other PCB circuits, devices, or a combination thereof, the peripheral region corresponding to a periphery of the planar magnetic circuit device.

9. The planar magnetic circuit device of Claim 1, wherein the respective first halves of the multiple separate windings of the first layer and the respective second halves of the multiple separate windings of the second layer are configured to contribute to magnetic core flux of the planar magnetic circuit device in a same sense.

10. The planar magnetic circuit device of Claim 1, wherein the cutout region is configured to enable a first portion of the magnetic core to mate with a second portion of the magnetic core.

11. The planar magnetic circuit device of Claim 1 , wherein the pair of layers of the PCB is a first pair of layers of a plurality of pairs of layers of the PCB and wherein each pair of layers of the plurality of pairs of layers is configured to implement multiple respective separate windings that encircle the cutout region.

12. The planar magnetic circuit device of Claim 1, wherein the planar magnetic circuit device is a multi-coil transformer, center-tapped transformer, inductor, or other planar magnetic circuit device.- 20 -4170643. vl0278.204900113. A computer-implemented method for implementing a planar magnetic circuit device, the computer-implemented method comprising: producing an electronic representation of a printed circuit board (PCB) of the planar magnetic circuit device, the electronic representation produced including a cutout region for containing at least a portion of a magnetic core, a first layer of a pair of layers of the PCB in the electronic representation produced including respective first halves of multiple separate windings that wind around the cutout region via respective turns, a second layer of the pair of layers of the PCB in the electronic representation including respective second halves of the multiple separate windings; and outputting the electronic representation produced toward manufacturing the PCB of the planar magnetic circuit device.

14. The computer-implemented method of Claim 13, wherein the multiple separate windings are multiple separate conductive traces.

15. The computer-implemented method of Claim 13, wherein the magnetic core includes at least one ferromagnetic core.

16. The computer-implemented method of Claim 13, wherein producing the electronic representation includes wiring the respective first halves of the multiple separate windings of the first layer to the respective second halves of the multiple separate windings of the second layer via metallic interconnections in the electronic representation produced.

17. The computer-implemented method of Claim 13, wherein the cutout region is a center cutout region located between two other cutout regions of the PCB in the electronic representation, wherein producing the electronic representation includes routing the respective first halves of the multiple separate windings of the first layer to encircle the center cutout region in a same direction, and wherein the same direction a clockwise direction or a counterclockwise direction.

18. The computer-implemented method of Claim 13, wherein the cutout region is a center cutout region located between two other cutout regions of the PCB in the electronic representation, wherein producing the electronic representation includes routing the- 21 -4170643. vl0278.2049001 respective second halves of the multiple separate windings of the second layer to encircle the center cutout region in a same direction, and wherein the same direction is a clockwise direction or a counterclockwise direction.

19. The computer-implemented method of Claim 13, wherein producing the electronic representation includes routing the respective first halves of the multiple separate windings to spiral outward within the first layer from a bordering region of the first layer toward a peripheral region of the first layer, the bordering region bordering the cutout region and enabling connections between the first layer and other layers of the PCB, the peripheral region enabling connections to other PCB circuits, devices, or a combination thereof, the peripheral region corresponding to a periphery of the planar magnetic circuit device.

20. The computer-implemented method of Claim 13, wherein producing the electronic representation includes routing the respective second halves of the multiple separate windings to spiral outward within the second layer from a bordering region of the second layer toward a peripheral region of the second layer, the bordering region bordering the cutout region and enabling connections between the second layer and other layers of the PCB, the peripheral region enabling connections to other PCB circuits, devices, or a combination thereof, the peripheral region corresponding to a periphery of the planar magnetic circuit device.

21. The computer-implemented method of Claim 13, wherein producing the electronic representation includes routing the respective first halves of the multiple separate windings of the first layer and the respective second halves of the multiple separate windings of the second layer in a manner that causes the respective first halves and respective second halves to contribute to magnetic core flux of the planar magnetic circuit device in a same sense.

22. The computer-implemented method of Claim 13, wherein the pair of layers of the PCB is a first pair of layers of a plurality of pairs of layers of the PCB in the electronic representation and wherein producing the electronic representation includes employing each pair of layers of the plurality of pairs of layers to implement multiple respective separate windings that encircle the cutout region.- 22 -4170643. vl0278.204900123. A non-transitory computer-readable medium for implementing a planar magnetic circuit device, the non-transitory computer-readable medium having encoded thereon a sequence of instructions which, when loaded and executed by at least one processor, causes the at least one processor to: produce an electronic representation of a printed circuit board (PCB) of a planar magnetic circuit device, the electronic representation produced including a cutout region for containing at least a portion of a magnetic core, a first layer of a pair of layers of the PCB in the electronic representation produced including respective first halves of multiple separate windings winding around the cutout region via respective turns, a second layer of the pair of layers including respective second halves of the multiple separate windings; and output the electronic representation produced toward manufacturing the PCB of the planar magnetic circuit device.

24. A printed circuit board (PCB) for a planar magnetic circuit device, the PCB comprising: a cutout region; a first layer of a pair of layers of the PCB, the first layer configured to include respective first halves of multiple separate windings, the multiple separate windings configured to wind around the cutout region via respective turns; and a second layer of the pair of layers, the second layer configured to include respective second halves of the multiple separate windings, the cutout region configured to contain at least a portion of the magnetic core of the planar magnetic circuit device.4170643. vl

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