A switching power supply system-in-package structure

Abstract

The application discloses a switching power supply system-level packaging structure in the field of power supply packaging, which comprises a control unit circuit module, a high-frequency transformer module and a power switch conversion circuit module made by using a hybrid integrated circuit process, the control unit circuit module and the power switch conversion circuit module are interconnected by metal wiring, and the power switch conversion circuit module is connected with the pins of the high-frequency transformer module. The switching power supply system-level packaging design is based on a three-dimensional structure realized by a multilayer substrate, the control unit circuit, the high-frequency transformer and the power switch conversion circuit are modularized into modules, the electrical connection between the modules is realized through internal metallization wiring, a BGA (or a welding surface) is designed at the bottom to realize the input and output of the switching power supply, and thus a stacked three-dimensional structure is formed, the volume is effectively reduced by 50%, and the power density is increased by 1 times.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power supply packaging, in particular to a switching power supply system-level packaging structure. BACKGROUND

[0002] Switching power supply as the heart of electronic equipment, in the whole system occupies a large proportion. With the development of the whole system miniaturization, light weight, switching power supply itself miniaturization, light weight demand has been inevitable. At present, the switching power supply is still based on the circuit board as the conventional carrier in two-dimensional plane expansion circuit wiring design, although the circuit structure has been designed as compact as possible, but the volume of switching power supply in the plane does not have too much compressible margin, at the same time, the plane design structure also leads to the lengthening of the current path line, increases the path current loss, when high frequency switching, easy to produce larger parasitic parameters, affect the performance quality of switching power supply, therefore, the traditional switching power supply design method can not meet the current demand, the applicant puts forward the improvement scheme. SUMMARY

[0003] The purpose of the present application is to provide a switching power supply system-level packaging structure, the control unit circuit, power conversion unit circuit and power transformer in the switching power supply are modularized designed, and the modules are three-dimensional integrated module designed, realizing the miniaturization, high performance, multifunction, high reliability and low cost of switching power supply, solving the problems in the above background technology.

[0004] In order to achieve the above purpose, the present application provides the following technical scheme:

[0005] A switching power supply system-level packaging structure, comprising a control unit circuit module, a high-frequency transformer module and a power switch conversion circuit module made of hybrid integrated circuit process, the control unit circuit module and the power switch conversion circuit module are interconnected by metal wiring, and the power switch conversion circuit module is connected with the pins of the high-frequency transformer module.

[0006] Further, the control unit circuit module and the power switch conversion circuit each include a main body structure composed of a plurality of substrates, and electronic devices for constituting a circuit are arranged on the substrate, and the electronic devices are electrically interconnected by metal lines between the substrates.

[0007] Further, the high-frequency transformer module comprises a main body structure composed of a plurality of Al2O3 substrates, a three-dimensional metal wiring structure is arranged inside the main body structure, a primary winding, a secondary winding and an auxiliary winding are arranged on the main body structure, and the coils of each winding are interconnected by the three-dimensional metal wiring structure.

[0008] Further, the top surface of the main structure of the control unit circuit module is provided with a resistance-capacitance array composed of multiple components, and the top surface is also provided with a photoelectric coupler, and the bottom of the main structure is provided with multiple IC controllers, and the resistance-capacitance array, the photoelectric coupler and the IC controllers constitute the control unit circuit, and the control unit circuits are connected by metal through holes inside the main structure.

[0009] Further, the control unit circuit module is composed of a multilayer HTCC substrate or a LTCC substrate to form a main structure.

[0010] Further, the substrate of the high-frequency transformer module and / or the power switch conversion circuit module is manufactured by a multilayer sintering process, and a hole for stress release is formed on the back surface of the substrate or the copper foil blank of the metal line guide belt.

[0011] Beneficial effects: the switch power supply system level packaging design based on the multilayer substrate realizes the three-dimensional structure, modularizes the control unit circuit, the high-frequency transformer and the power switch conversion circuit, forms a module, realizes the electrical connection between the modules through the internal metallization wire, designs the BGA (or welding surface) at the bottom, realizes the input and output of the switch power supply, and thus forms the stacked three-dimensional structure, effectively reduces the volume by 50%, and improves the power density by 1 times. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a schematic diagram of the principle of the application;

[0013] Figure 2 is a schematic diagram of the overall structure of the application;

[0014] Figure 3 is a three-dimensional structure diagram of the control unit circuit module of the application;

[0015] Figure 4 is a sectional view of the control unit circuit module of the application;

[0016] Figure 5 is a three-dimensional structure diagram of the high-frequency transformer module of the application;

[0017] Figure 6 is a schematic diagram of the high-frequency transformer module of the application;

[0018] Figure 7 is a three-dimensional structure diagram of the power switch conversion circuit of the application;

[0019] Figure 8 is a sectional view of the power switch conversion circuit of the application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0021] Referring to Figures 1-2 A switching power supply system level package structure includes a control unit circuit module, a high-frequency transformer module and a power switch conversion circuit module made by using a hybrid integrated circuit process. The control unit circuit module and the power switch conversion circuit module are interconnected by metal wiring, and the power switch conversion circuit module is connected with the pins of the high-frequency transformer module. The control unit circuit, the high-frequency transformer and the power switch conversion circuit realize the basic components of the switching power supply circuit function, wherein the control unit circuit is composed of a core IC controller, a resistance-capacitance array and a photoelectric coupler; the power switch conversion circuit is composed of a power drive, a power switch tube, a power rectifier tube and an energy storage filter circuit.

[0022] The control unit circuit module (PWM control unit and auxiliary function unit circuit) is an important component in the switching power supply control system, which controls the conduction duty cycle of the power switch tube, and has functions such as overvoltage protection, undervoltage protection, prohibition and output short circuit protection.

[0023] The DC voltage input from the outside is converted into high-frequency pulses by the power conversion circuit module 1, and after isolation and coupling and voltage conversion by the high-frequency transformer module 2, the DC voltage is obtained by rectification and filtering by the power conversion circuit module 1. In order to realize the required stable output voltage, the control unit circuit module 3 directly samples the output voltage, compares and amplifies it with the reference voltage, and then feeds back through the photoelectric coupling to control the duty cycle of the power conversion circuit module 1, thereby realizing closed-loop control of the output voltage.

[0024] Since the control unit circuit and the power switch conversion circuit used in the switching power supply of the present embodiment are conventional circuit structures, through mechanism and characteristic analysis and research on the conventional switching power supply circuit, the control unit circuit module of the present application integrates the primary side control circuit and the secondary side control circuit together, shortens the signal transmission path and reduces the parasitic parameters; the power switch conversion circuit module integrates the primary side drive and the secondary side rectification together, shortens the large current transmission path and reduces the path loss; the high-frequency transformer module integrates the transformer and the output energy storage inductor together, adopts magnetic integration technology, and effectively reduces the volume. Through the unit division of the switching power supply circuit, a unit circuit standardized module is formed, and the switching power supply design is simplified.

[0025] The control unit circuit, the high-frequency transformer and the power switch conversion circuit become a control unit circuit module, a high-frequency transformer module and a power switch conversion circuit module after realizing modular design. Each module realizes miniaturization by using three-dimensional wiring. Then, each module is integrally assembled and designed. The modules are interconnected reliably by hard connection in three layers of upper, middle and lower layers in three-dimensional micro-assembly. The path of large current is interconnected by copper needle, and the signal is interconnected by soft connection. In addition to improving the performance index of the switching power supply, the power supply product volume is further miniaturized, and the power supply product power density is improved.

[0026] Specifically, the control unit circuit module and the power switch conversion circuit each include a main structure composed of multiple layers of substrates, and electronic devices for constituting a circuit are arranged on the substrates, and the electronic devices are electrically interconnected by metal lines between the substrates.

[0027] The control unit circuit module is realized based on a LTCC (Low Temperature Co-fired Ceramic) / HTCC (High Temperature Co-fired Ceramic) multilayer substrate. Circuit components are arranged on the top and bottom surfaces of the structure, as shown in Figures 3-4 The top surface of the main structure of the control unit circuit module 3 is arranged with a resistance-capacitance array composed of components 301, 303, 304, 305 and 306, and also arranged with an optoelectronic coupler 302. The bottom of the main structure is arranged with IC controllers 307, 308 and 309. The resistance-capacitance array, the optoelectronic coupler 302 and the IC controllers 307, 308 and 309 constitute a control unit circuit, and the circuits are electrically interconnected by metal vias in the main structure.

[0028] Since the chips of the IC controllers 307, 308 and 309 adopt a fan-out technology, the electrical connection between electronic components is interconnected by blind buried holes and multilayer wiring. Therefore, in addition to the characteristics of strong driving ability, full function and small size, this control unit circuit module effectively reduces the two-dimensional plane area of the control unit circuit by 40%, further reduces the volume of the switching power supply and improves its power density. The above integrated process can realize vertical interconnection, shorten the signal transmission path, reduce the parasitic parameters and improve the performance quality of the switching power supply.

[0029] The power switch conversion circuit module is the unit with the largest power loss and heat consumption in the switching power supply. Considering heat dissipation, a HTCC multilayer substrate is adopted, as shown in Figures 7-8As shown, the top surface of the main structure of the power switching converter circuit module is equipped with components 101, 102, 103, 104, and 105, some of which are power switching transistors and rectifier diodes. The bottom surface is equipped with BGA pads, which serve as the output pads for the switching power supply. Components 101 to 105 constitute the power switching converter circuit. The chip adopts fan-out technology, and the electrical interconnection between the components is achieved through the metallized lines inside the substrate.

[0030] The power conversion unit circuit (power switching and rectification / filtering unit circuit) is a crucial component of power conversion in a switching power supply system. Its function is to convert the input voltage and current into the voltage and current required by the output load. In this embodiment, the components of the improved power switching circuit module are electrically connected using blind vias and multi-layer wiring, effectively reducing the two-dimensional planar area by up to 30%, further reducing the size of the switching power supply and increasing its power density.

[0031] like Figures 5-6 As shown, to reduce size and improve conversion efficiency, the high-frequency transformer employs magnetic integration technology, and utilizes a sandwich structure and Al2O3 multi-layer copper paste fabrication. The high-frequency transformer module consists of a multi-layer Al2O3 substrate forming the main structure, with the top surface of the main structure ( Figure 5 The left side) is equipped with the primary winding and the secondary winding, and the bottom surface ( Figure 5 (On the right side) Auxiliary windings are arranged, and three-dimensional metal wiring is achieved on the Al2O3 substrate through blind and buried vias and multi-layer wiring. The coils of each winding are interconnected through the three-dimensional metal wiring structure. The high-frequency transformer module effectively reduces the two-dimensional planar area by up to 30%, further reducing the size of the switching power supply and increasing its power density.

[0032] In addition, the substrate of the high-frequency transformer module and / or the power switch conversion circuit module uses a multi-layer sintering technology in the manufacturing process technology to conduct heat and release thermal stress in the process of reducing the volume. The copper-coated substrate of the high-frequency transformer and the power switch conversion circuit will generate a large thermal stress when the temperature cycles between -65°C and 150°C, causing the copper skin to warp or causing micro-cracks in the ceramic substrate, resulting in circuit failure. Therefore, the copper-coated substrate is simulated, and a hole for stress release is opened at the place where a large thermal stress is generated, i.e. at the blank of the copper foil of the metal circuit lead or at the back of the ceramic plate. Generally, it is a Φ0.3mm round or polygonal chocolate block, and a row of Φ0.2mm mesh holes (stamp holes) are designed at the edge of the copper foil of the metal circuit lead to achieve the effect of thermodynamic equilibrium design and heat dissipation design. In the micro-assembly process technology, the substrate uses multi-temperature gradient assembly, multi-chip fan-out technology, multi-layer vertical interconnection technology, small-size component high-density assembly technology (represented by 0402 / 0201 / 01005 devices), 3D packaging structure BGA interconnection technology, etc. Since these processes and multi-layer sintering processes are common process technologies for substrate manufacturing, they will not be described here.

[0033] Since the control unit circuit module, the power switch conversion circuit module, and the high-frequency transformer module all use LTCC / HTCC hybrid integration technology to realize modular design, they respectively play a role in reducing the size of the switching power supply. After the three modules are packaged at the system level, the switching power supply can finally be designed in a package with a length, width, and height of 12.70mm×12.70mm×12.70mm. Compared with conventional switching power supplies, the volume is reduced by 50%. Moreover, since the main structure of each module uses a ceramic carrier with good thermal conductivity, it also has good heat dissipation performance, which improves the service life of the switching power supply. The present application is mainly used in the fields of DC-DC converter, other control unit circuit modularization, miniaturization, and integrated design.

[0034] Although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. The description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0035] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of the application; that is, any equivalent variations made within the scope of the claims of the present application are within the protection scope of the claims of the present application.

Claims

1. A switching power supply system-in-package structure, characterized in that, It includes a control unit circuit module, a high-frequency transformer module, and a power switch conversion circuit module, all manufactured using hybrid integrated circuit technology. The control unit circuit module and the power switch conversion circuit module are interconnected by metal wiring, and the power switch conversion circuit module is connected to the pins of the high-frequency transformer module. Both the control unit circuit module and the power switch conversion circuit include a main structure composed of a multilayer substrate, and electronic devices for forming the circuit are arranged on the substrate. The electronic devices are electrically interconnected through metal lines between the substrates. The high-frequency transformer module is composed of a multi-layer Al2O3 substrate as the main structure. The main structure has a three-dimensional metal wiring structure inside. The main structure is equipped with primary winding, secondary winding and auxiliary winding. The coils of each winding are interconnected through the three-dimensional metal wiring structure.

2. The switching power supply system-level package structure according to claim 1, characterized in that, The top surface of the main structure of the control unit circuit module is provided with an array of resistors and capacitors consisting of multiple components, and an optocoupler is also provided on the top surface. The bottom of the main structure is provided with multiple IC controllers. The array of resistors and capacitors, the optocoupler and the IC controllers constitute the control unit circuit. The control unit circuits are connected to each other by metal through holes inside the main structure.

3. The switching power supply system-level packaging structure according to claim 1, characterized in that, The control unit circuit module is mainly composed of a multilayer HTCC substrate or LTCC substrate.

4. The switching power supply system-level package structure according to claim 1, characterized in that, The substrates of the high-frequency transformer module and / or power switch conversion circuit module are all manufactured by a multi-layer sintering process, and holes for stress relief are opened on the back of the substrate or in the blank space of the copper foil of the metal line conductor.

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