Isolation power supply of magnetic core-embedded substrate transformer and preparation method of isolation power supply

Abstract

The invention discloses an isolation power source of an embedded magnetic core substrate transformer and a preparation method of the isolation power source, and relates to the technical field of transformers, the isolation power source comprises the embedded magnetic core transformer, a transmitting chip and a receiving chip, and the transmitting chip and the receiving chip are connected with the embedded magnetic core transformer; the coil assembly comprises a primary coil LP and a secondary coil LS which are arranged in the vertical direction, an isolation medium is arranged between the primary coil LP and the secondary coil LS, and the isolation medium is used for transmission of alternating current; the number of the magnetic cores is at least one, and the magnetic cores are arranged in the vertical direction of the coil assembly; according to the invention, the magnetic core is embedded between the primary coil LP and the secondary coil LS, so that the obtained transformer with the embedded magnetic core breaks through the performance limitation of a transformer without a magnetic core; meanwhile, the consumed area is smaller, and the inductance value, the quality factor, the coupling coefficient and the like are higher.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and in particular to an isolated power supply of an embedded magnetic core substrate transformer and a preparation method thereof. Background Art

[0002] Isolated power supplies are widely used in industries such as industry, automotive electronics, and biomedicine. The ability of current isolation can effectively eliminate pulses, glitches, and potential ground loops between different voltage domains, and plays a vital role in ensuring that the system works safely and reliably in harsh industrial environments.

[0003] Traditional isolated power supplies have problems such as low efficiency, large size, high electromagnetic noise and high cost. Therefore, in applications where size and cost are limited, it is still a great challenge to efficiently transmit hundreds of milliwatts of power through isolation devices. Compared with traditional optocoupler isolation devices, fully integrated isolated power chips based on micro-transformers have the advantages of good isolation performance, high magnetic interference immunity, small size and monolithic integration.

[0004] Currently, the fully integrated isolated power chip implementation solution [Reference W. Qin et al., "An 800mWFully Integrated Galvanic Isolated Power Transfer System Meeting CISPR 22Class-B Emission Levels with 6dB Margin," 2019 IEEE International Solid-State Circuits Conference - (ISSCC), San Francisco, CA, USA, 2019] is as follows Figure 1 As shown. This solution combines and packages multiple chips by gold wire bonding, including a coreless transformer chip 100 made by a back-end silicon-based process, a transmitter chip 200 and a receiver chip 300 made by a high-voltage BCD process. However, due to the lower inductance (15nH) and smaller quality factor (6.8) of the coreless transformer, the isolated power supply needs to operate at a switching frequency of tens or even hundreds of megahertz, which limits the transmission efficiency (34%) and output power (800mW), and becomes a strong radiation source that interferes with the normal operation of other devices. In addition, the coreless transformer chip is large in size and has a relatively low transmission efficiency, so the traditional isolated power supply packaging has high cost, low power density, and low conversion efficiency.

[0005] Therefore, in order to break through the performance limitations of coreless transformers and achieve greater transmission efficiency and output power under chip size constraints, thereby improving power density, a compact and high-performance transformer and chip fully integrated solution is needed. Summary of the invention

[0006] The purpose of the present invention is to provide an isolated power supply of an embedded magnetic core substrate transformer and a preparation method thereof, so as to solve the following technical problems: Traditional isolated power supplies use large magnetic core transformers, which are expensive and bulky, making it difficult to achieve full integration. Traditional fully integrated isolated power chips use coreless transformers, which consume a large packaging area and increase the difficulty and cost of chip packaging; Traditional fully integrated isolated power chips use coreless transformers with low inductance and quality factor, which limits the transmission efficiency and output power of the isolated power supply.

[0007] The purpose of the present invention can be achieved through the following technical solutions: An isolated power supply of an embedded magnetic core substrate transformer includes an embedded magnetic core transformer and a transmitting chip and a receiving chip connected thereto, wherein the embedded magnetic core transformer includes: The coil assembly includes a primary coil L arranged in a vertical direction. P and the secondary coil L S , the primary coil L P and the secondary coil L S An isolation medium is provided between the two electrodes, and the isolation medium is used for transmitting alternating current; The magnetic core is at least one and is arranged in the vertical direction of the coil assembly.

[0008] As a further solution of the present invention: the primary coil L P Set the secondary coil L S above or below.

[0009] As a further solution of the present invention: the primary coil L P , secondary coil L S It is a polygonal coil or a spiral coil.

[0010] As a further solution of the present invention: the magnetic core is one and is embedded above or below the coil assembly.

[0011] As a further solution of the present invention: there are two magnetic cores, one each embedded above and below the coil assembly.

[0012] As a further solution of the present invention: when there is more than one magnetic core, they can be in a vertical direction with the coil assembly.

[0013] As a further solution of the present invention: the magnetic core is one of a ferrite core, a nickel-zinc core, a manganese-zinc core and a sendust core.

[0014] A method for preparing an isolated power supply of an embedded magnetic core substrate transformer comprises the following steps: frame manufacturing, carrier film pasting, magnetic core pasting, magnetic core embedding, carrier film removal and subsequent higher-level manufacturing.

[0015] As a further solution of the present invention: the production of the middle frame includes the following steps: photosensitive medium pattern production, pattern electroplating, photosensitive medium removal, medium layer lamination, carrier plate removal and etching.

[0016] Beneficial effects of the present invention: The present invention is in the primary coil L P and the secondary coil L S The buried core transformer obtained by embedding the magnetic core between the two components not only breaks through the performance limitation of the coreless transformer, but also consumes a smaller area and has a higher inductance value, quality factor and coupling coefficient, etc. Compared with the coreless transformer, the core transformer of the present invention has a smaller magnetic resistance and can obtain a larger inductance under the same area, so a smaller area will be consumed to achieve the same inductance value.

[0017] Compared with a conventional fully integrated isolated power supply, the isolated power supply of the embedded magnetic core substrate transformer of the present invention can obtain higher transmission efficiency and output power. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] Figure 1 It is a schematic diagram of the prior art structure; Figure 2 It is a schematic diagram of the overall structure of the present invention; Figure 3 It is a schematic diagram of the overall structure of the embedded magnetic core transformer of the present invention; Figure 4 It is a structural schematic diagram of a first embodiment of an embedded magnetic core transformer of the present invention; Figure 5 is a structural schematic diagram of a second embodiment of an embedded magnetic core transformer of the present invention; Figure 6 is a schematic structural diagram of a third embodiment of an embedded magnetic core transformer of the present invention; Figure 7 It is a schematic diagram of the simulation result of the inductance value of the embedded magnetic core transformer of the present invention; Figure 8 It is a schematic diagram of the simulation result of the Q value of the embedded magnetic core transformer of the present invention; Fig. 9It is a schematic diagram of the simulation result of the coupling coefficient of the embedded magnetic core transformer of the present invention; Fig.10 It is a process flow chart for preparing an isolated power supply of an embedded magnetic core substrate transformer of the present invention.

[0020] In the figure: 100, embedded magnetic core transformer; 200, transmitting chip; 300, receiving chip. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Example 1

[0023] See also Figure 2 As shown, the present invention is an isolated power supply with an embedded magnetic core substrate transformer. The isolated power supply combines and packages multiple chips through wafer-level packaging or gold wire bonding, including an embedded magnetic core transformer 100 manufactured using a back-end silicon-based process, a transmitting chip 200 and a receiving chip 300 manufactured using a silicon process, thereby achieving a smaller package size and improving the integration of the isolated power supply.

[0024] Embedded core transformer 100: consists of a primary coil L P and the secondary coil L S Composition, primary coil L P and the secondary coil L S The spatial position of is not limited and can be Figure 3 Shown L S In L P Above, it can also be L S In L P Above: Primary coil L P and the secondary coil L S It is implemented by a polygonal coil method and can also be implemented by a spiral method. There is an isolation medium between the two, which can isolate the DC voltage and realize the transmission of AC power; it also includes an embedded magnetic core material for improving the performance of the transformer, and the performance improvement includes but is not limited to inductance value, quality factor and coupling coefficient, etc.; the magnetic core material includes but is not limited to ferrite core, nickel-zinc core, manganese-zinc core and sendust core, etc., and the performance improvement includes but is not limited to inductance value, quality factor and coupling coefficient, etc.

[0025] Transmitter chip 200: used to convert the input DC voltage V INThe high frequency oscillation power signal is converted into a differential and output to the primary coil L of the embedded magnetic core transformer 100. P ; Receiving chip 300: used to embed the secondary coil L of the magnetic core transformer 100 S The received high frequency oscillating AC voltage is rectified into a DC voltage V ISO and supplied to the load.

[0026] Specifically, Figure 4 The embedded core transformer proposed in this paper is composed of a primary coil L P , secondary coil L S The two coils are made on the metal layers M1 and M2 of the substrate respectively, and are led out through through holes for electrical connection.

[0027] Primary coil L P , secondary coil L S The spatial position of is not limited and can be Figure 4 The secondary coil L shown S In the primary coil L P Above, it can also be the secondary coil L S In the primary coil L P There is an insulating layer (isolation medium) between the two coils, which can isolate the DC voltage and realize the transmission of AC power; in the primary coil L P , secondary coil L S Below the metal layer, that is, between M3 and M4, there is a magnetic core material for improving the performance of the transformer.

[0028] Example 2

[0029] The magnetic core can be embedded in the primary coil L P , secondary coil L S Above the metal layer, such as Figure 5 shown.

[0030] Example 3

[0031] There can be multiple magnetic cores at the same time, for example, magnetic core 1 and magnetic core 2 can be embedded in the primary coil L respectively. P , secondary coil L S Above and below the metal layer, such as Figure 6 shown.

[0032] The inductance, quality factor and coupling coefficient of the embedded magnetic core transformer in Examples 1-3 were measured: See also Figure 7 As shown, the inductance value of the embedded magnetic core transformer proposed in the above embodiment is, at a frequency (such as 80MHz), the primary coil L PThe inductance value is 163nH, and the secondary coil L s The inductance value is 140nH, which is 70% higher than that of a coreless transformer of the same area and shape.

[0033] like Figure 8 As shown, the quality factor (Q value) of the embedded core transformer proposed in the above embodiment is, at a frequency (such as 80MHz), the primary coil L P The Q value is 29, and the secondary coil L s The Q value is 34, which is improved compared to coreless transformers of the same area and shape.

[0034] like Fig. 9 As shown, the coupling coefficient (k value) of the embedded core transformer proposed in the above embodiment is 0.83 at a frequency (such as 80 MHz). Compared with a coreless transformer of the same area and shape, the k value is increased by 15.3%.

[0035] Therefore, the present invention is in the primary coil L P and the secondary coil L S The embedded magnetic core transformer 100 obtained by embedding the magnetic core between the two components not only consumes a smaller area, but also has a higher inductance value, quality factor, coupling coefficient, etc.

[0036] Example 4

[0037] See also Fig.10 As shown: A method for preparing an isolated power supply of an embedded magnetic core substrate transformer includes the following steps: frame production, carrier film pasting, magnetic core pasting, magnetic core embedding, carrier film removal and subsequent higher-level production. The middle frame production includes the following steps: photosensitive medium pattern production, pattern electroplating, photosensitive medium removal, dielectric layer lamination, carrier plate removal and etching.

[0038] After the magnetic sheet is embedded and the carrier film is removed, the next process is ABF pressing and circuit production, layer by layer; this process is an existing process and is the same as the PCB preparation process.

[0039] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. An isolated power supply with an embedded magnetic core substrate transformer, comprising an embedded magnetic core transformer (100) and a transmitting chip (200) and a receiving chip (300) connected thereto, characterized in that: The embedded magnetic core transformer (100) comprises: The coil assembly includes a primary coil L arranged in a vertical direction. P and the secondary coil L S , the primary coil L P and the secondary coil L S An isolation medium is provided between the two electrodes, and the isolation medium is used for transmitting alternating current; The magnetic core is at least one and is arranged in the vertical direction of the coil assembly.

2. The isolated power supply of the embedded magnetic core substrate transformer according to claim 1, characterized in that: The primary coil L P Set the secondary coil L S above or below.

3. The isolated power supply of the embedded magnetic core substrate transformer according to claim 1, characterized in that: The primary coil L P , secondary coil L S It is a polygonal coil or a spiral coil.

4. The isolated power supply of the embedded magnetic core substrate transformer according to claim 1, characterized in that: The magnetic core is one and is embedded above or below the coil assembly.

5. The isolated power supply of the embedded magnetic core substrate transformer according to claim 1, characterized in that: There are two magnetic cores, one each embedded above and below the coil assembly.

6. The isolated power supply of the embedded magnetic core substrate transformer according to claim 1, characterized in that: When there is more than one magnetic core, they can be in a vertical direction with the coil assembly.

7. An isolated power supply with an embedded magnetic core substrate transformer according to any one of claims 1 to 6, characterized in that: The magnetic core is one of a ferrite magnetic core, a nickel-zinc magnetic core, a manganese-zinc magnetic core and a sendust magnetic core.

8. A method for preparing an isolated power supply of an embedded magnetic core substrate transformer, characterized in that: The following steps are involved: Frame production, carrier film pasting, core pasting, core embedding, carrier film removal and subsequent higher-level production.

9. The method for preparing an isolated power supply of an embedded magnetic core substrate transformer according to claim 8, characterized in that: The middle frame production includes the following steps: photosensitive medium pattern production, pattern electroplating, photosensitive medium removal, medium layer lamination, carrier plate removal and etching.

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