INTEGRATED POWER INDUCTOR WITH BOTTOM ELECTRODE WITHOUT CARRIER AND MANUFACTURING METHOD THEREOF

Abstract

A integrated power inductor integrated with bottom electrode without carrier, the power inductor is composed of a coil, a tin layer, and a magnetic powder envelope etc, wherein the wire of the coil is directly drawn to the bottom of the magnetic powder envelope without via a carrier as an electrode, thereby effectively reducing the risk of the inductor being opened due to too small or incomplete welding points between the coil and the material sheet, and can greatly improve the characteristics, reliability and manufacturing yield of the inductor,

Claims

1. A integrated power inductor integrated with bottom electrode without carrier, the power inductor is composed of a coil, a tin layer, and a magnetic powder envelope; wherein the coil includes a coil body wound in a spiral shape, and a first lead wire and a second lead wire extending from the ends of the coil, the ends of the first lead and the second lead are covered with a tin layer externally, and the coil is covered by the magnetic powder envelope body; characterized in that: a carrier is not provided inside said magnetic powder envelope, and the ends of the first lead wire and the second lead wire of the coil body are exposed from the bottom of the magnetic powder envelope as a bottom electrode.

2. The integrated power inductor integrated with bottom electrode without carrier as claimed in claim 1, wherein the ends of the first lead wire and the second lead wire exposed from the bottom of the magnetic powder envelope are flat lead plate.

3. The integrated power inductor integrated with bottom electrode without carrier as claimed in claim 2, wherein the flat lead plate is covered with a tin layer on the outside.

4. The integrated power inductor integrated with bottom electrode without carrier as claimed in claim 2, wherein the ends of the first lead wire and the second lead wire of the coil body are bent so that the flat lead plate is located below said coil body.

5. The integrated power inductor integrated with bottom electrode without carrier as claimed in claim 2, wherein the flat lead plates of the first lead and the second lead are arranged in parallel and extending in the same direction or opposite direction.

6. A manufacturing method for integrally forming a power inductor with bottom electrode without carrier as claimed in claim 1, the manufacturing steps include: a coil forming step, a flattening step, a bending step, and a die casting step.

7. The method for integrally forming a power inductor with bottom electrode without carrier as claimed claim 6, wherein the coil forming step is to prepare a spiral coil, the coil body of the spiral coil can be round shape, flat shape or other shapes, it is better to use copper wire, and the first and second lead wires protrude from both ends of the coil body.

8. The method for integrally forming a power inductor with bottom electrode without carrier as claimed in claim 7, wherein the flattening step is to press the ends of the first lead and the second lead of the coil body, to make it a flat lead plate.

9. The method for integrally forming a power inductor with bottom electrode without carrier as claimed in claim 8, wherein the step of bending is to fold the first lead and the second lead end so that its flat lead plates are located below the to coil body.

10. The method for integrally forming a power inductor with bottom electrode without carrier as claimed in claim 9, wherein the step of molding is to place said coil body, the first and second lead wire having plate shaped lead plate is placed in a mold, and to fill the magnetic powder in the mold; after die-casting and demolding operations, the entire shape is covered with a magnetic powder envelope, and a partially flat shape-shaped lead plate is exposed as the bottom electrode for power inductor.

11. The method for integrally forming a power inductor with bottom electrode without carrier as claimed in claim 10, wherein before the step of bending, a step of tinning can be added by covering the outside of the flat guide plate with a tin layer to form a flat tin layer.

12. The method for integrally forming a power inductor with bottom electrode without carrier as claimed in claim 10, wherein after the step of molding, the flat lead plate exposed from the bottom of the magnetic powder envelope can be subjected to a tin plating process.

13. The method for integrally forming a power inductor with bottom electrode without carrier as claimed in claim 12, wherein the magnetic powder envelope can be covered with an insulating layer, after the die casting step and before a tin plating process is performed.

14. The method for integrally forming a power inductor with bottom electrode without carrier as claimed in claim 10, wherein if the molding step is completed, while a flat guide plate or a bottom of the magnetic powder envelope is not exposed, a grinding step may be added to expose the flat guide plate or the flat tin layer from the bottom of the magnetic powder envelope as a bottom electrode.

15. The method for integrally forming a power inductor with bottom electrode without carrier as claimed in claim 8, wherein the flattening step may not pressurize the ends of the first and second lead wires of the coil body; instead, a flat material piece is welded to the end of said first lead wire and the end of said second lead wire.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a perspective view of the connection between the common spiral coil and lead frame.

[0019] FIGS. 2A to 2D are schematic diagrams of the finished product using the various manufacturing steps for forming the common power inductor with side electrodes and bottom electrodes.

[0020] FIGS. 3A to 3D are schematic diagrams of the finished products of various manufacturing steps for forming common power inductor with only a bottom electrode by using of a carrier.

[0021] FIGS. 4A to 4D are schematic diagrams of the finished products of various manufacturing steps for forming common power inductor with only a bottom electrode by using a platform carrier.

[0022] FIG. 5A is a three-dimensional schematic diagram showing a power inductor in which the bottom electrode of the present invention is integrally formed without using a carrier.

[0023] FIG. 5B is a side view of FIG. 5A.

[0024] FIG. 6 is a flow chart showing the manufacturing steps of the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0025] FIG. 7A is a side view of the coil in the coil forming step of the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0026] FIG. 7B is a bottom view of FIG. 7A.

[0027] FIG. 8A is a side view of the coil in the flattening step of the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0028] FIG. 8B is a bottom view of FIG. 8A.

[0029] FIG. 9A is a side view of the coil in the step of upper tin layer formation of the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0030] FIG. 9B is a bottom view of FIG. 9A.

[0031] FIG. 10A is a side view of the coil in the step of bending the lead wires to the bottom of the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0032] FIG. 10B is a bottom view of FIG. 10A,

[0033] FIG. 11A is a side view of the power inductor in the die-casting step of the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0034] FIG. 11B is a bottom view of FIG. 11A.

[0035] FIG. 12A is a side view of the power inductor in the insulation coating step of the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0036] FIG. 12B is a bottom view of FIG. 12A.

[0037] FIG. 13A is a side view of the power inductor in the grinding step of the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0038] FIG. 13B is a bottom view of FIG. 13A.

[0039] FIG. 14A is another schematic perspective view of another coil in the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention,

[0040] FIG. 14B is a schematic perspective view of another coil in the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0041] FIG. 14C is another side view of the coil in the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0042] FIG. 14D is a schematic perspective view of a coil in another flattening step of the method for manufacturing a integrated power inductor with bottom electrode without carrier of the present invention.

[0043] FIG. 15 is a relative comparison diagram of the saturation current characteristic curves of the integrated power inductor with bottom electrode without carrier of the present invention and a conventional inductor through experimental tests.

[0044] FIG. 16 is a comparative comparison diagram of the conversion efficiency curves of the integrated power inductor with bottom electrode without carrier of the present invention and the conventional inductor through light load experiments.

[0045] FIG. 17 is a comparative comparison of the conversion efficiency curves of the integrated power inductor with bottom electrode without carrier of the present invention and the conventional inductor through heavy load experiments.

DETAILLED DESCRIPTION OF' PREFERRED EMBODIMENT

[0046] The power inductor of the present invention is integrally formed with a bottom electrode without a carrier. As shown in FIGS. 5A and 5B, the power inductor 200 is composed of a coil 300, a tin layer 400, and a magnetic powder envelope 500. The magnetic powder envelope 500 may be any shape. As shown in the figures, the coil 300 includes a coil body 301 wound in a spiral shape, a first lead wire 302 and a second lead wire 303 extending horizontally from the end of the coil body 301; the end of first lead wire 302 and the second lead wire 303 are formed as flat lead plates 302A and 303A, and the flat lead plates 302A and 303A are covered with a tin layer 400 and bent under the coil body 301. The tin layer 400 at the bottom of the magnetic powder envelope 500 is used as a bottom electrode,

[0047] As shown in FIG. 6, the manufacturing process steps of integrally forming a power inductor without a bottom electrode of the present invention include: a coil forming step 200A, a flattening step 200B, a tin layer covering step 200C, a bending step 200D, a die casting step 200E, a insulation coating step 200F, and a grinding step 200G; the above steps are stated as follows.

[0048] The coil forming step 200A: as shown in FIGS. 7A and 7B, a spiral coil is prepared. The wire of the coil body 301 may be round, flat or other shapes, and copper wires are preferred. The first wire 302 and the second wire 303 of the two end wires of the coil body 301 protrude outward on both sides;

[0049] The flattening step 200B: as shown in FIGS. 8A and 8B, the ends of the first lead wire 302 and the second lead wire 303 of the coil body 301 are pressurized to become flat plates 302A and 303A;

[0050] The tin layer covering step 200C: as shown in FIGS. 9A and 9B, a tin layer covering process is performed on the two flat lead plates 302A and 303A, so that each of the flat lead plates 302A and 303A is covered with a tin layer 400;

[0051] The bending step 200D: as shown in FIGS. 10A and 10B, the flat lead plates 302A and 303A of the outer coating tin layer 400 are bent downward to the lower part of the coil body 301;

[0052] The die casting step 200E: as shown in FIGS. 11A and 11B, the entire spiral coil 300, the flat lead plates 302A and 303A covered with the tin layer 400 are placed into the mould together through the molding process; The coil 300 can be fixed in the mold by the support of the flat lead plates 302A and 303A folded back to the bottom; when the magnetic powder is filled in the mold and then perform the process of die-casting and demolding, such that the power inductor 200 coated with magnetic powder envelope 500 is obtained;

[0053] The insulation coating step 200F: as shown in FIGS. 12A and 12B, insulation coating is performed on the outer surface of the magnetic powder envelope 500 to form an insulating layer 501, thereby protecting the magnetic powder envelope 500 from being affected by subsequent processes;

[0054] The grinding step 200G: as shown in FIGS. 13A and 13B, the bottom of the magnetic powder envelope 500 is polished to expose the tin layer 400 at the bottom of the flat lead plates 302A and 303A as a bottom electrode to be connected to electrical components such as circuit boards.

[0055] The power inductor of the present invention is integrally formed by the flat lead plates 302A and 303A of the wire coated with a tin layer 400 and exposed at the bottom of the magnetic powder envelope 500 as a bottom electrode, the structure also can be manufactured through the above-mentioned manufacturing process, and can also be adjusted during implementation. For example, as shown in 14A, a flat wire spiral coil 600 wound with a flat wire may be used; or as shown in FIG. 14B, the first lead wire 601 and the second lead wire 602 at both ends of the coil may be respectively extended in opposite directions, or as shown in

[0056] FIG. 14C, the flat lead plates 701 and 702 of the wire on both sides of the spiral coil are oppositely bent.

[0057] In addition, in the flattening step, the ends of the first lead and the second lead may not be pressed and flattened, but as shown in FIG. 14D, a flat sheet 801 is directly welded to the end of the lead wire, while the length of the wire welding section 802 by the wire end is equivalent to the length of the flat sheet 801. As the welding part is extended, the welding strength is increased, which can avoid the disadvantage of conventional spot welding and does not affect the internal design space of the magnetic powder envelope.

[0058] Furthermore, the step 200C of the said tin layer may be omitted, and instead, after the grinding step 200G is completed, a flat lead plate or a flat material sheet as a bottom electrode is exposed under the magnetic powder envelope, and then form the electroplating tin layer.

[0059] In addition, the grinding step 200F may be omitted, and the tin layer 400 is directly exposed on the bottom of the magnetic powder envelope 500 as a bottom electrode by directly designing the mold, after completing the die casting step 200E.

[0060] The integrated power inductor with the bottom electrode without carrier of the present invention has been experimentally proved that, as shown in FIG. 15, it is shown that in the products with same specifications, the power inductor of the present invention has a zero bias current (BIAS) of 0˜30 ampere, the saturation current characteristic of the power inductor of the present invention is significantly better than the conventional power inductor. The date of comparison are shown as follows:

TABLE-US-00001 Inductance DC resistance [mΩ] Saturation current [A] +/− worst Best 20% [μH] average value average value The 1 5 5.2 23 21 present Conventional 1 5.5 6.1 19 16 one

[0061] In addition, as shown in FIG. 16 and FIG. 17, whether a light load product with a load current of 0.5 to 8 amperes such as a mobile phone or a high load product with a load. current of 10 to 40 amperes, such as electrical equipment, The conversion efficiency of the power inductor of the present invention to the central processing unit is better than the conventional power inductor.

[0062] Therefore, the integrated power inductor with the bottom electrode without carrier manufactured by the above-mentioned manufacturing process has the following characteristics:

[0063] 1. No carrier is used, so that the magnetic powder envelope can achieve optimal space utilization, and obtain higher magnetic saturation current and lower DC resistance.

[0064] 2. using the coil wire directly as the bottom electrode can help to reduce the loss of magnetic powder. For the client's power conversion management system, it can provide better conversion efficiency and meet customers' requirements for power specifications

[0065] 3. it can prevent the risk of short circuit caused by over dense of inductor arrangement, so that the power conversion management system of the client can have more space for use or meet the miniaturization requirements of the client's demands.

[0066] 4. Different from the conventional power inductor with the spot welding of the wire is used as the electrode. The present invention allows the wire to be directly led out to the bottom as an electrode, which can effectively reduce the risk of incomplete spot welding of the wire and the sheet, causing the risk of open circuits. The reliability of the inductor is greatly improved.

[0067] 5. The risk of side cracks caused by the material is also reduced.

[0068] Based on the above, The integrated power inductor with bottom electrode without carrier and manufacturing method thereof of is not commonly seen in a similar one, which undoubtedly includes a novel and practical features never seen in conventional ones, and then comply the conditions of allowable patents.

[0069] What described above are for illustrating the preferred embodiments of the present invention, not for limiting the structure and features of the present invention. Any person skilled in the art shall be able to make modifications and changes to the embodiments without departing from the spirit of the present invention.