High-frequency switching power supply magnetic device with high power density

Abstract

The invention relates to a high-power-density high-frequency switching power supply magnetic device, and belongs to the technical field of high-frequency switching power supplies. Aiming at the problems of the existing switching power supply magnetic device, the invention provides a novel device suitable for a high-power-density high-frequency switching power supply magnetic device, which mainly comprises a magnetic core made of a magnetic material, a ceramic substrate, an interconnection conductive pattern on the substrate, an interlayer insulating material and a winding interconnection material, and the high-power-density and small-size process integration can be realized, and the requirements of good heat dissipation, high reliability and high-temperature environment can be met.

Description

Technical Field

[0001] The invention relates to a high-frequency switching power supply magnetic device with high power density, belonging to the technical field of high-frequency switching power supplies. The device is a transformer or an inductor. Background Art

[0002] With the continuous improvement of the power density of switching power supplies, the switching frequency of switching power supplies is required to be continuously increased, while the size of switching power supplies is continuously reduced, resulting in large bottlenecks in the size, heat dissipation, and reliability of magnetic devices (power transformers and inductors), which is not conducive to the improvement of the power density of switching power supplies and the needs of process integration. In addition, the enameled wire windings or planar transformer windings made of printed circuit boards currently used in the mainstream have poor heat dissipation capabilities, and the temperature rise of transformers and inductors is high, which is not conducive to the operation of switching power supplies in high temperature environments. In other words, during the entire working life of the switching power supply, the enameled wires or printed circuit board wires inside the transformers and inductors will continue to age as the working time increases, seriously affecting the long-term reliability of the switching power supply system. For this reason, it is also necessary to find power transformers and inductors that can better meet the requirements of high frequency, miniaturization, and integration of switching power supplies. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to propose a high-power density high-frequency switching power supply magnetic device, and to address the problems existing in the existing switching power supply magnetic devices. A novel high-power density high-frequency switching power supply magnetic device is proposed, which is mainly composed of a magnetic core made of magnetic material, a ceramic substrate and interconnected conductive patterns on the substrate, interlayer insulating materials, and winding interconnection materials. It can adapt to the requirements of good heat dissipation, high power density and small volume process integration, high reliability and high temperature environment.

[0004] The technical solution of the present invention is:

[0005] A high-power density high-frequency switching power supply magnetic device, the device comprises a magnetic core 1 made of magnetic material and a plurality of substrates;

[0006] Each base body includes a ceramic substrate 2, an interlayer insulating layer 3 and a connecting rod 4;

[0007] The plurality of substrates are placed inside the magnetic core 1;

[0008] An interlayer insulating layer 3 is provided between two adjacent ceramic substrates 2, and the ceramic substrate 2 and the interlayer insulating layer 3 are connected by an adhesive 5;

[0009] Filling the gap between the magnetic core 1 and the substrate with thermally conductive silicone 6;

[0010] A dielectric slurry and a conductive slurry are brushed on the ceramic substrate 2 and fired to form a wire winding pattern. One end of the wire winding is connected to the connecting rod 4, and the other end of the wire winding is connected to the outside world as a bonding point. The bonding point is connected to the outside world through a silicon aluminum wire or a copper wire. There are through holes (vias) on the ceramic substrate 2, which are used as connection channels between adjacent wire windings.

[0011] The magnetic core 1 is a magnetic core suitable for bonding or mechanical fixing that can be purchased on the market, such as E type, EC type, ER type, EQ type, ETD type, EER type, P type, PQ type, RM type, etc. Since the winding of the transformer needs to be led out, the magnetic core needs to have a side opening. The inner cavity of the magnetic core can be equipped with multiple substrates.

[0012] The magnetic device uses a ceramic substrate 2 as a winding forming carrier. Such as alumina ceramics, beryllium oxide ceramics, LTCC green ceramic tape, HTCC green ceramic tape, etc. Generally, ceramics with high dielectric constant and excellent mechanical properties are used. Due to the limitations of the height of the magnetic device and the volume of the inner cavity, the thickness of this type of ceramic is relatively thin, and the thickness of a single layer is generally less than 2mm.

[0013] The wire winding on the ceramic substrate 2 is made in the following ways: 1. The wire for high current is made by printing patterns and sintering at high temperature; 2. The wire for low current is deposited at high temperature by vacuum coating. The wire is often made of palladium silver, copper and other materials with strong conductivity, which can carry high current density. The winding is covered with an interlayer insulation layer 3 with good insulation performance. The insulation layer is a high-voltage material, such as ceramic fiber, polyimide, polytetrafluoroethylene, glass fiber, insulating paint, etc. There are two ways to fix the insulating material: 1. Directly spray it on the substrate; 2. Bond the film material to the substrate.

[0014] Each layer of the ceramic substrate 2 is electrically interconnected through vias on the substrate. The vias can be injected with conductive materials or the conductor connecting rods can be inserted into the vias. The substrates are evenly coated with adhesive materials with strong adhesive force to achieve tight connection through mechanical pressure. Adhesive materials such as epoxy, etc.

[0015] The magnetic cores are fixed together tightly by adhesive, and the adhesive is magnetic conductive glue or red glue. The ceramic substrate and the magnetic core are cured and shaped by injecting thermal conductive silicone.

[0016] The lead-out terminals of the magnetic device are interconnected with the peripheral printed circuit board and ceramic substrate in the following ways: 1. Interconnection by bonding using conductive materials such as silicon aluminum wire or copper wire; 2. Interconnection by welding using conductive materials such as leads.

[0017] The present invention relates to a high-power density high-frequency switching power supply magnetic device and implementation method, belonging to the technical field of high-frequency switching power supplies, including: 1. The composition of the magnetic device, a magnetic core made of magnetic material, a transformer or inductor winding, a ceramic substrate, and an external connecting wire. 2. The process implementation of the magnetic device: the molding of the winding on the ceramic substrate, the bonding of the ceramic substrate, the interconnection of the ceramic substrate, and the bonding of the magnetic material. It is suitable for the design and manufacture of transformers or inductors in high-frequency switching power supplies. The present invention solves the shortcomings of poor heat dissipation, poor reliability, and temperature rise in the existing switching power supply power transformer and inductor technology, and has the advantages of good heat transfer, adaptability to higher temperature environments, easy integration, and small size. The device is suitable for high-power density high-frequency switching power supply magnetic devices (transformers and inductors), including a magnetic core made of magnetic material, a ceramic substrate, and interconnected wires on the substrate to realize the design and manufacture of high-frequency transformers, and adapt to good heat dissipation requirements, high power density and small volume process integration, high reliability requirements and high temperature environment requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the appearance diagram of the transformer of the present invention;

[0019] Figure 2 It is a transformer composition diagram of the present invention;

[0020] Figure 3 It is a schematic diagram of the conductive pattern of the transformer substrate of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] Example

[0023] like Figure 1 As shown, a device suitable for high power density high frequency switching power supply magnetic device is made. The shape and volume of the magnetic core are related to the conversion power. The magnetic core adopts EI type magnetic core or other shapes of magnetic cores as required. The magnetic cores are bonded together by magnetic conductive glue. After curing, the final magnetic device is formed. Its height is determined by the height of the magnetic core and the thickness of the magnetic conductive glue. The magnetic core and several substrates in the inner cavity are cured and shaped by encapsulating thermal conductive silica gel 6. The palladium silver pad at the lead end of the device is bonded to the peripheral circuit connection point with multiple Ф300μm silicon aluminum wires (depending on the current size) to achieve interconnection.

[0024] like Figure 2As shown, the wire windings between adjacent ceramic substrates are connected by connecting rods, the layers are insulated by polyimide film, the substrates are positioned by positioning holes, the substrates are electrically interconnected by connecting rods 4 passing through the vias, and the bonding material between the ceramic substrates is epoxy glue, which tightly bonds several layers of substrates together to form a matrix. Multilayer ceramic substrates can be made according to the current bearing conditions of the windings.

[0025] like Figure 3 As shown, the corresponding winding pattern is designed by computer-aided software according to the configuration requirements of the power and number of turns of the magnetic device, and printed on the ceramic substrate 2 to form a printed pattern. The ceramic substrate 2 is placed in a high-temperature sintering furnace, and a solidified pattern is formed after high-temperature sintering. The dielectric can be thickened or the protective layer can be fired multiple times as needed. The ceramic substrate 2 uses a single-layer 0.5mm thick HTCC raw ceramic tape (A92W) or other ceramic materials mentioned above. The upper surface of the ceramic substrate 2 is brushed with a dielectric slurry, and a wire winding made of palladium silver slurry is fired above the dielectric slurry. One end of the wire winding is connected to the connecting rod 4, and the other end of the wire winding is connected to the peripheral circuit through a silicon aluminum wire as a bonding point. There is a through hole (via) on the ceramic substrate 2 as a connection channel for the wire winding of the adjacent interlayer substrate;

[0026] Finally, it should be noted that the above examples are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the invention.

[0027] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-power density high-frequency switching power supply magnetic device, characterized in that: The device comprises a magnetic core (1) made of magnetic material and a plurality of substrates; Each base body comprises a ceramic substrate (2), an interlayer insulating layer (3) and a connecting rod (4); The plurality of substrates are placed inside the magnetic core (1); An interlayer insulating layer (3) is provided between two adjacent ceramic substrates (2), and the ceramic substrates (2) and the interlayer insulating layer (3) are bonded together by an adhesive (5); The gap between the magnetic core (1) and the base body is filled with thermally conductive silica gel (6).

2. The high power density high frequency switching power supply magnetic device according to claim 1, characterized in that: The adhesive is epoxy resin.

3. The high power density high frequency switching power supply magnetic device according to claim 1, characterized in that: The ceramic substrate (2) is provided with interconnected conductive patterns.

4. The high power density high frequency switching power supply magnetic device according to claim 1, characterized in that: The upper surface of the ceramic substrate (2) is coated with dielectric slurry, and a wire winding made of fired conductive slurry is disposed above the dielectric slurry. One end of the wire winding is connected to a connecting rod (4), and the other end of the wire winding is connected to a peripheral circuit as a bonding point.

5. The high power density high frequency switching power supply magnetic device according to claim 4, characterized in that: The bonding points are connected to the peripheral circuits through silicon-aluminum wires or copper wires.

6. The high power density high frequency switching power supply magnetic device according to claim 1, characterized in that: The ceramic substrate (2) is provided with through holes, which are used as connection channels between adjacent wire windings.

7. The high power density high frequency switching power supply magnetic device according to claim 1, characterized in that: The magnetic core made of magnetic material adopts E type, EC type, ER type, EQ type, ETD type, EER type, P type, PQ type or RM type.

8. The high power density high frequency switching power supply magnetic device according to claim 1, characterized in that: The material of the ceramic substrate (2) is alumina ceramic, beryllium oxide ceramic, LTCC green ceramic tape or HTCC green ceramic tape, and the thickness of a single layer is less than 2 mm.

9. The high power density high frequency switching power supply magnetic device according to claim 1, characterized in that: The wire winding on the ceramic substrate is made in the following way: (1) The high current conductors are printed and sintered at high temperature; (2) Low current conductors are deposited at high temperatures by vacuum coating; The conductor material is palladium silver or copper, and the winding is covered with a high-voltage material, which is ceramic fiber, polyimide, polytetrafluoroethylene, glass fiber or insulating paint; There are two ways to fix high pressure materials: (1) Spray directly onto the substrate; (2) Bonding the film material to the substrate.

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