RU2726628C1 - Radio-electronic unit - Google Patents

Abstract

FIELD: instrument engineering.SUBSTANCE: invention relates to a radio electronic unit used in making optoelectronic devices with sufficiently high density of internal space. Radio electronic unit comprises a power and control board with power supply and control elements and a system board with sensitive analogue radio elements, output connectors on the boards, inter-board connections and a fastening module. At that, power and control elements are located on external side of power supply and control board, sensitive analogue radio elements are located on external side of system board, inter-board connections are made in the form of opposite connectors on the boards, the attachment module is a fastening metal frame with holes for attachment elements located between the boards. At the same time in stack of layers of both boards there laid are shielding layers connected to mounting frame through metallized holes in boards and between which there are layers of sensitive analogue and high-speed digital circuits. In stack of layers of each board there are blind transition metalized holes for transition of signals between external and closest to them extreme internal signal layers, as well as hidden transient metallized holes for transition of signals between opposite extreme internal signal layers.EFFECT: high electromagnetic compatibility of the radio electronic unit while maintaining dense electronics layout and small weight and size characteristics.1 cl, 2 dwg

Description

The invention relates to the development of designs for printed circuit boards and radio electronic units that can be used in optoelectronic devices for various purposes.

At present, high requirements are imposed on optical-electronic devices (OED) in terms of electromagnetic compatibility, reliability, weight and size characteristics and manufacturability. Therefore, there is a problem of increasing the electromagnetic compatibility while maintaining or reducing the mass and size characteristics of the OES.

Known radio electronic unit (RF Patent No. 2172081, IPC H05K 1/00 (2000.01), H05K 1/11 (2000.01), H05K 1/14 (2000.01), H05K 3/46 (2000.01) published on 08/10/2001) containing a multilayer printed circuit board with the number of conductive layers N≥6, in which high-frequency and low-frequency connectors are placed on the outer first and Nth conductive layers, as well as printed conductors, contact pads and electrical radio elements, grouped by functional zones. Ground planes are located in inner conductive layers adjacent to outer conductive layers.

The disadvantage of the radio electronic unit is that the shielding layers inside the printed circuit board are designed to shield elements located in different functional areas on the board and do not provide sufficient protection against external electromagnetic influences.

The radio electronic unit is also known (RF Patent No. 2366125, IPC H05K 1/00 (2006.01), H05K 1/18 (2006.01), H05K 9/00 (2006.01), H05K 3/40 (2006.01), H05K 3/46 (2006.01) ) published on August 27, 2009), which improves the efficiency of protecting the radio electronic unit from the effects of electromagnetic interference and radio interference by using the spatial resources of printed circuit boards in it and manufacturing a shield protecting against electromagnetic interference by filling the metallized groove with solder connecting the shielding printed conductors and ground planes.

The disadvantages are the absence of permanent connections between the boards and the unit case, as well as the complexity of the installation of the radio-electronic unit, during which there is a high probability of violation of technological standards, which will lead to a decrease in the effectiveness of the protection of the radio-electronic unit from the effects of electromagnetic interference.

The closest to the claimed technical solution in terms of the technical essence and the achieved technical result is the electronic unit (RF Patent No. 174943, IPC H05K 9/00 (2006.01), published on 11/14/2017), consisting of a body with holes made in it for external connectors, system board, bottom cover, power board, power supply modules, filter modules, the case is divided into a power section and a system section. Common features are the division of electronics by functional purpose into two separate boards: the power and control board, on which the power and control elements are located, and the system board, on which the sensitive analog radio elements are located. Also, printed circuit boards have output connectors, board-to-board connections, elements and fasteners, while the boards are electrically connected to the case (ground).

The main disadvantages of the prototype are the need to divide the radio-electronic unit into isolated compartments, to organize a protective shield between the boards, as well as the need to use an external protective shield in the form of a metal case against electromagnetic interference, which significantly affects the weight and size characteristics of the devices.

The technical objective of the present invention is to improve the electromagnetic compatibility of the radio electronic unit while maintaining a dense layout of electronics and small weight and size characteristics.

The technical result is achieved by the fact that in the electronic unit containing the power and control board, on which the power and control elements are located, and the system board with sensitive analog radio elements located on it, the output connectors made on the boards, board-to-board connections, the fastening module, according to this According to the invention, power and control elements are located on the outside of the power and control board, sensitive analog radio elements are located on the outside of the motherboard, board-to-board connections are made in the form of opposite connectors on the boards, the fastening module is a fastening metal frame with holes for fastening elements located between the boards , while the layer stack of both boards contains shielding layers, which are connected to the mounting frame through plated holes in the boards and between which layers of sensitive analog and high-speed digital circuits are located, and in the layer stack each This board has blind metalized vias to provide signal transitions between the outer and the nearest innermost signal layers, as well as hidden metallized vias for signal transitions between opposite outermost inner signal layers.

The essence of the invention, its feasibility and the possibility of industrial application are illustrated by the drawings shown in FIG. 1, 2, where:

FIG. 1 - electronic unit;

FIG. 2 - stack of layers of printed circuit boards.

The numbers in FIG. 1, 2 indicate the following positions:

1. electronic unit;

2. power and control board;

3. batteries and controls;

4. motherboard;

5. sensitive analog radioelements;

6.output connectors;

7. board-to-board connections;

8. metal frame;

9. holes on the metal frame;

10. fastening elements;

11. plated holes in the boards;

12. shielding layers;

13. dielectric layers;

14. blind transitional metallized holes;

15. hidden vias plated;

16. layers of sensitive analog and high-speed digital circuits;

17. gaps between printed conductors;

18. external signal layers;

19. internal signal layers.

The radio electronic unit 1 (Fig. 1) contains a power and control board 2, on which power and control elements 3 are located, and a system board 4 with sensitive analog radio elements 5 located on it, as well as a fastening module made in the form of a metal frame 8 with holes 9 for fastening elements 10, while the boards are equipped with output connectors 6, and board-to-board connections 7.

Power and control elements 3 are located on the front side of the power and control board 2, sensitive analog radio elements 5 are located on the front side of the motherboard 4, board-to-board connections 7 are made in the form of opposite connectors located on the back side of the boards, the metal frame 8 of the mounting module is located between the rear sides of boards 2 and 4, while the power and control board 2 and the motherboard 4 are made multilayer, the stacks of layers of multilayer boards 2 and 4 contain external 18 and internal 16, 19 signal layers, dielectric layers 13 and shielding 12 layers, while the internal signal layers 16 sensitive analog and high-speed digital circuits are located between the shielding layers 12, the contact of the shielding layers 12 with the metal frame 8 is through metalized through holes 11 made in the boards 2, 4 and the metal frame 8. The layer stacks have blind vias 14 to ensure transition signal als between the outer 18 and the nearest outermost inner 19 signal layers, as well as hidden vias 15 for the transition of signals between the opposite outermost inner signal layers 19.

An example of the implementation of a stack of layers of printed circuit boards is shown in Fig. 2, which in the particular case of execution in terms of the number and structure of the layer stack is the same for both printed circuit boards.

On the power and control board 2, the tracing of the circuits of the power elements and the circuits of the control elements is performed on the outer 18 and the closest to it the extreme inner signal layer 19 of the board. The transition between the layers of these circuits is made using blind vias 14. On the next layer there is an earthen polygon that acts as a shielding layer 12. The stack of PCB layers is made in the form of a symmetrical structure, so the number and purpose of layers relative to the central dielectric layer 13 is the same. Between the two shielding layers 12 are layers 16 of sensitive analog and high-speed digital circuits. The shielding layers 12 are connected to each other by hidden vias 15. The shielding layers 12 are also connected to the metallized fastening holes 11, through which they are connected to the metal frame 8 of the fastening module and the product body (not shown in the figure) by means of fastening elements 10. Total printed The board can consist, for example, of N≥8 metallization layers, depending on the number of radioelements located on it and the number of electrical connections between them.

The structure of the layer stack of the motherboard 4 is performed in a similar way. Sensitive analog radioelements are located on the outer side 5 of the motherboard 4, and layers 16 of sensitive analog and high-speed digital circuits are located on the inner layers between the shielding layers 12 connected to the metallized holes 11 and the metal frame 8 by the fastening elements 10.

The operation of the device can be described as follows.

During operation, on the power supply and control board 2, voltages are formed, which are necessary for the operation of the motherboard 4 and the components of the product for which the radio electronic unit 1 is intended. The process of supply voltages formation is inevitably accompanied by electromagnetic interference. This electromagnetic interference does not affect the operation of the motherboard 4 because in the proposed technical solution, they are localized on the front side of the power and control board 2, due to which the sensitive radio elements 5 located on the front side of the motherboard 4 are protected from their impact. In this case, the power and control board 2 and the motherboard 4 also have good protection against external electromagnetic interference, since sensitive analog and high-speed digital circuits are located on the inner layers 16 of printed circuit boards 2, 4 between shielding layers 12, which are interconnected by blind vias 14 along all boundaries of shielding ground layers 12, which provides a closed loop around sensitive analog and high-speed digital circuits. The presence of blind vias 14 makes it possible to ensure the flow of supply currents on the outer layers of printed circuit boards without a through transition between the layers, which makes it possible to minimize the number of discontinuities in the shielding layers 12, due to which the electromagnetic fields arising at the boundaries of the discontinuities due to an increase in inductance do not affect the sensitive analog and high speed digital circuits.

In the claimed solution, the electrical and radio elements on the boards are grouped in such a way that the power and control elements are placed on the front side of the power and control board, and the sensitive analog radio elements are located on the front side of the motherboard. This allows you to localize electromagnetic interference on the front side of the power and control board and not affect the correct operation of the motherboard, as well as increase the density of the electronics layout. Unlike the prototype, where the role of the screen is played by the dividing wall between the boards, in the electronic unit there is no additional screen between the boards, and its function is performed by ground shielding layers inside the stack of PCB layers, which protect sensitive analog and high-speed digital circuits from external electromagnetic influences. In the proposed technical solution, there are no through vias, the shielding layers are connected to the metallized holes of the printed circuit boards, which are installed on a metal frame and have an electrical connection with the case. This additionally allows you to get rid of the influence of external electromagnetic interference, which leads to an increase in the electromagnetic compatibility of the claimed device as a whole. In this case, the boards are made with the possibility of docking directly into each other using board-to-board connections, and the fastening module is a metal frame with holes, which, together with the above advantages, makes it possible to improve the weight and size characteristics of the electronic unit.

The proposed invention is technically feasible and industrially realizable at an instrument-making enterprise, the tests carried out confirm the achievement of the claimed technical result.

Claims (1)

A radio electronic unit containing a power and control board, on which power and control elements are located, and a system board with sensitive analog radio elements located on it, as well as a fastening module, while the boards are equipped with output connectors and board-to-board connections, characterized in that the batteries and controls are located on the front side of the power and control board, sensitive analog radio elements are located on the front side of the motherboard, board-to-board connections are made in the form of opposite connectors located on the back side of the boards, the fastening module is a metal frame with holes for fastening elements located between the back sides boards, while the power and control board and the motherboard are made multilayer, the stacks of layers of multilayer boards contain external and internal signal layers, dielectric and shielding layers, while the internal signal layers are sensitive analog and high high-speed digital circuits are located between the shielding layers, the contact of the shielding layers with the metal frame is through metalized through holes made in the boards and the metal frame, in addition, there are blind metalized vias in the layer stacks to ensure the transition of signals between the outer and the nearest innermost signal layers, as well as hidden vias plated for the transition of signals between the opposite extreme inner signal layers.

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