CN113784505A - 90-degree bridge circuit board optimization structure and manufacturing method thereof - Google Patents

Abstract

The invention discloses an optimized structure of a 90-degree bridge circuit board and a manufacturing method thereof, wherein the optimized structure comprises a printed circuit board, a radio frequency magnetic powder magnetic ring, a ceramic capacitor, silicon rubber, an enameled wire and high-temperature tin, three capacitor bonding pads and six welding spot bonding pads are arranged on the surface of the printed circuit board, six conducting bonding pads are arranged on the bottom surface of the printed circuit board, and the upper and lower conduction is realized through side surface via holes; the ceramic capacitor is welded to a capacitor bonding pad by high-temperature tin soldering, the enameled wire is wound on the radio-frequency magnetic powder magnetic ring and is fixed on the surface of the printed circuit board by silicon rubber bonding, an input wire head and an output wire head of the enameled wire are welded to a welding spot bonding pad of the printed circuit board, the welding spot bonding pad is welded to the input wire head or the output wire head by high-temperature tin soldering, and two welding spot bonding pads are respectively and electrically connected with the capacitor bonding pads at one ends of the two ceramic capacitors. The invention changes the ceramic capacitor common bonding pad into the independent welding spot bonding pad, so that the enameled wire is directly connected with the welding spot bonding pad, the welding spot bonding pad is separated from the ceramic capacitor bonding pad, and the problem of stress damage of the secondary welding of the ceramic capacitor by the welding spot bonding pad is solved.

Description

90-degree bridge circuit board optimization structure and manufacturing method thereof

Technical Field

The invention relates to an optimized structure of a 90-degree electric bridge circuit board and a manufacturing method thereof, belonging to the technical field of 90-degree electric bridges.

Background

With the increasing development of research personnel in China, the continuous improvement and progress of research technology, and with the continuous innovation of electronic technology, the miniaturization, ultra-thinning and superior performance of electronic product equipment in structure become the trend of manufacturing industry, which requires the development of microwave magnetic devices towards short, small, light, thin, high electrical performance and high reliability. The existing 90-degree bridge device structure has the advantages that a welding point welding pad is shared by a welding point welding pad of an enameled wire and a ceramic capacitor, so that the stress damage problem in the welding process of components and parts caused by the welding point welding pad of the enameled wire and the stress mechanical damage problem caused by secondary tin coating at the position of the welding point welding pad of the components and parts are easily caused.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: a90-degree bridge circuit board optimized structure and a manufacturing method thereof are provided to solve the problems in the prior art.

The technical scheme adopted by the invention is as follows: a90-degree bridge circuit board optimized structure comprises a printed circuit board, a radio frequency magnetic powder magnetic ring, a ceramic capacitor, silicon rubber, an enameled wire and high-temperature tin, wherein three capacitor bonding pads and six welding spot bonding pads are arranged on the surface of the printed circuit board, six conducting bonding pads are arranged on the bottom surface of the printed circuit board, and the printed circuit board is conducted up and down through side surface via holes; the ceramic capacitor is welded to a capacitor bonding pad by high-temperature tin soldering, the enameled wire is wound on the radio-frequency magnetic powder magnetic ring and is fixed on the surface of the printed circuit board by silicon rubber bonding, an input wire head and an output wire head of the enameled wire are welded to a welding spot bonding pad of the printed circuit board, the welding spot bonding pad is welded to the input wire head or the output wire head by high-temperature tin soldering, and two welding spot bonding pads are respectively and electrically connected with the capacitor bonding pads at one ends of the two ceramic capacitors.

Preferably, the input line head and the output line head of the enameled wire are spot-welded on a point welding pad of the printed circuit board by adopting a pulse electronic spot welding machine.

A method of manufacturing an optimized 90 ° bridge circuit board structure, the method comprising the steps of:

(1) printing solder paste on three capacitor bonding pads of the printed circuit board by using a steel mesh, mounting the ceramic capacitor on the capacitor bonding pads of the printed circuit board by using a chip mounter, and performing capacitor welding by using a reflow soldering machine;

(2) firstly, twisting enameled wires with 4 colors to wind inductance coils L3, L4, L5 and L6 on a first radio frequency magnetic powder magnetic ring; twisting and braiding number of enameled wires: 80 circles/20 cm; then, carrying out line scattering treatment on the welt enameled wire; winding inductance coils L1 and L7, L2 and L8 on a second radio frequency magnetic powder magnetic ring after the two lines are subjected to kinking treatment;

(3) the method comprises the following steps of respectively welding the wire ends of inductance coils L1, L7, L2 and L8 on corresponding input/output bonding pads by using a pulse electronic spot welding machine, and respectively welding the wire ends of the inductance coils L3 and L4 and the wire ends of the inductance coils L5 and L6 at corresponding center tapping positions; the welding parameters of the spot welding machine are as follows:

pulse rising angle: 50-60 degrees; paint removal pulse: 60% -70%; welding force: 4.5N-6.5N; pulse amplitude: 155mV-170 mV; pulse width: 11mS-14 mS;

(4) carrying out secondary welding treatment on the welding spots by using high-temperature tin wires; the welding spot is required to be smooth and round, and the height of the welding spot cannot exceed 1.5 mm; the welding temperature is as follows: 390 +/-10 ℃;

(5) fixing the magnetic ring on the printed circuit board by using white silica gel; naturally drying the silica gel for more than 24 hours;

(6) packaging with white epoxy resin with shearing force being greater than or equal to 20N/mm and a white ceramic shell; curing temperature of epoxy resin: 125 ℃, curing time: for 90 minutes.

The invention has the beneficial effects that: compared with the prior art, the invention changes the ceramic capacitor common bonding pad into the independent welding spot bonding pad by changing the layout of the ceramic capacitor bonding pad on the printed circuit board and the routing of the printed circuit board, so that the enameled wire is directly connected with the welding spot bonding pad, the welding spot bonding pad is separated from the ceramic capacitor bonding pad, and the problem of stress damage of the secondary welding ceramic capacitor of the welding spot bonding pad is solved.

Drawings

FIG. 1 is a schematic diagram of a circuit board structure;

fig. 2 is a schematic diagram of a bridge circuit connection structure.

Detailed Description

The invention is further described with reference to the accompanying drawings and specific embodiments.

Example 1: as shown in fig. 1-2, a 90-degree bridge circuit board optimized structure comprises a printed circuit board 1, a radio frequency magnetic powder magnetic ring 2, a ceramic capacitor 3, silicon rubber 4, an enameled wire 5 and high-temperature tin 6, wherein three capacitor pads and six welding spot pads are arranged on the surface of the printed circuit board 1, six conducting pads are arranged on the bottom surface of the printed circuit board, and the printed circuit board is conducted up and down through side-surface via holes; ceramic capacitor 3 uses high temperature tin 6 to weld to the electric capacity pad, and enameled wire 5 twines on radio frequency magnetic powder magnetic ring 2 and adopts silicon rubber 4 bonding to fix on printed circuit board 1 surface, and the input end of a thread and the output end of enameled wire 5 weld to printed circuit board 1's solder joint pad, and the solder joint pad adopts high temperature tin 6 welding input end of a thread or output end of a thread, has two solder joint pads to be connected with the electric capacity pad electricity of two ceramic capacitor 3 one ends respectively. The welding point bonding pad of the enameled wire and the capacitor bonding pad connected with the ceramic capacitor are independently opened, so that stress damage in the welding process of the components and the mechanical damage caused by secondary tin coating at the position of the common bonding pad of the components and the components, which is caused by the common bonding pad of the components and the components, is effectively avoided. As shown in fig. 2, the input port pin6 is connected to the 0 ° output port pin2 through the inductors L1, L3, L5, and L7 connected in series in sequence, the isolation port pin5 is connected to the 90 ° output port pin1 through the inductors L2, L4, L6, and L8 connected in series in sequence, a ceramic capacitor C1 is connected between the inductors L3 and L5 and between the inductors L3 and L5, and two ends of the ceramic capacitor C1 are connected to the ground end through the ceramic capacitor C2 and the ceramic capacitor C3, respectively, and the above circuits form an ultra-thin 90 ° bridge, and when applied to a radio frequency circuit, an input signal can be divided into two signals that are equal in amplitude and have a phase difference of 90 °.

Preferably, the input line head and the output line head of the enameled wire 5 are spot-welded to the welding point welding pad of the printed circuit board 1 by using a pulse electronic spot welding machine.

The 90-degree electric bridge can be applied to a radio frequency circuit and can divide an input signal into two signals which are mutually equal in amplitude and have a 90-degree phase difference; the multi-signal combiner is mainly used for multi-signal combination, the utilization rate of output signals is improved, and low-loss transmission can be realized by the product.

The product is widely applied to various radio frequency circuits, and can realize that:

1. an input signal can be split into two signals of equal amplitude and with a phase difference of 90 deg.. The method is mainly used for multi-signal combination, and the utilization rate of output signals is improved;

2. the method has the advantages of low insertion loss, high isolation, small amplitude imbalance, small phase imbalance and small standing-wave ratio;

3. the electrical property stability is good, the reliability is high.

Example 2: a method of manufacturing an optimized 90 ° bridge circuit board structure, the method comprising the steps of:

(1) printing solder paste on three capacitor bonding pads of the printed circuit board 1 by using a steel mesh, mounting the ceramic capacitor on the capacitor bonding pads of the printed circuit board by using a chip mounter, and performing capacitor welding by using a reflow soldering machine; the thickness and the width of the solder paste can be ensured by using the steel mesh printing, and the consistency of the solder paste quantity is better, so that the phenomenon that a capacitor stands up in the reflow soldering process is avoided; the production efficiency, the welding consistency and the welding reliability are improved; the open circuit of the components caused by secondary reflow soldering tin melting can be solved by using the high-temperature solder paste;

(2) firstly, twisting enameled wires 5 with 4 colors to wind inductance coils L3, L4, L5 and L6 on a first radio frequency magnetic powder magnetic ring 2; twisting and braiding number of enameled wires: 80 circles/20 cm; then, carrying out line scattering treatment on the welt enameled wire; winding inductance coils L1 and L7, L2 and L8 on a second radio frequency magnetic powder magnetic ring 2 after the two lines are subjected to kinking treatment; the enameled wires are twisted to reduce the leakage inductance among the inductors and increase the mutual inductance; thereby reducing the loss of the bridge and improving the performance; the twisted twine can wind a plurality of groups of inductors at the same time, so that the number of turns is reduced, the threading efficiency is improved, and the threading error rate is reduced;

(3) the method comprises the following steps of respectively welding the wire ends of inductance coils L1, L7, L2 and L8 on corresponding input/output bonding pads by using a pulse electronic spot welding machine, and respectively welding the wire ends of the inductance coils L3 and L4 and the wire ends of the inductance coils L5 and L6 at corresponding center tapping positions; the welding parameters of the spot welding machine are as follows:

pulse rising angle: 50-60 degrees; paint removal pulse: 60% -70%; welding force: 4.5N-6.5N; pulse amplitude: 155mV-170 mV; pulse width: 11mS-14 mS; the paint removing pulse function is provided, paint removing and welding are integrated, and the reliability and efficiency of welding are ensured; the inductance lead can be fixed above the bonding pad by a pulse electronic spot welding machine, so that the welding process is convenient for welding;

(4) carrying out secondary welding treatment on the welding spots by using high-temperature tin wires; the welding spot is required to be smooth and round, and the height of the welding spot cannot exceed 1.5 mm; the welding temperature is as follows: 390 +/-10 ℃; performing secondary high-temperature tin welding on the welding spots to prevent open circuit of the bridge caused by insufficient welding of the welding spots;

(5) fixing the magnetic ring on the printed circuit board by using white silica gel; naturally drying the silica gel for more than 24 hours; the silicon rubber has the characteristics of good anti-vibration effect, good operability and the like; the silicon rubber is used for fixing the magnetic ring on the PCB, so that the magnetic ring can not fall off to cause the breakage and open circuit of the enameled wire when the bridge works in the high vibration, impact and acceleration environment;

(6) packaging with white epoxy resin with shearing force being greater than or equal to 20N/mm and a white ceramic shell; curing temperature of epoxy resin: 125 ℃, curing time: 90 minutes; the ceramic shell is used for packaging, so that components, magnetic rings and circuits are prevented from being directly exposed outside, and the components and the circuits can be prevented from being damaged in the installation process and the cleaning process.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present invention, and therefore, the scope of the present invention should be determined by the scope of the claims.

Claims (3)

1. The utility model provides a 90 electric bridge circuit board optimized structure which characterized in that: the printed circuit board comprises a printed circuit board (1), a radio frequency magnetic powder magnetic ring (2), a ceramic capacitor (3), silicon rubber (4), an enameled wire (5) and high-temperature tin (6), wherein three capacitor bonding pads and six welding spot bonding pads are arranged on the surface of the printed circuit board (1), six conducting bonding pads are arranged on the bottom surface of the printed circuit board, and the printed circuit board is conducted up and down through side surface via holes; ceramic capacitor (3) use high temperature tin (6) to weld on the electric capacity pad, enameled wire (5) winding is on radio frequency magnetic powder magnetic ring (2) and adopt silicon rubber (4) bonding to fix on printed circuit board (1) surface, the input end of a thread and the output end of enameled wire (5) weld on the solder joint pad of printed circuit board (1), the solder joint pad adopts high temperature tin (6) welding input end of a thread or output end of a thread, have two solder joint pads respectively with the electric capacity pad electricity of two ceramic capacitor (3) one ends be connected.

2. The optimized 90 ° bridge circuit board structure of claim 1, wherein: the input wire head and the output wire head of the enameled wire (5) are spot-welded on a welding spot welding pad of the printed circuit board (1) by adopting a pulse electronic spot welding machine.

3. The method for manufacturing the optimized structure of the 90 ° bridge circuit board according to claim 1, wherein: the method comprises the following steps:

(1) printing solder paste on three capacitor bonding pads of a printed circuit board (1) by using a steel mesh, mounting a ceramic capacitor on the capacitor bonding pads of the printed circuit board by using a chip mounter, and performing capacitor welding by using a reflow soldering machine;

(2) firstly, twisting enameled wires (5) with 4 colors to wind inductance coils L3, L4, L5 and L6 on a first radio frequency magnetic powder magnetic ring (2); twisting and braiding number of enameled wires: 80 circles/20 cm; then, carrying out line scattering treatment on the welt enameled wire; winding inductance coils L1 and L7, L2 and L8 on a second radio frequency magnetic powder magnetic ring (2) after the two lines are subjected to kinking treatment;

(3) the method comprises the following steps of respectively welding the wire ends of inductance coils L1, L7, L2 and L8 on corresponding input/output bonding pads by using a pulse electronic spot welding machine, and respectively welding the wire ends of the inductance coils L3 and L4 and the wire ends of the inductance coils L5 and L6 at corresponding center tapping positions; the welding parameters of the spot welding machine are as follows:

pulse rising angle: 50-60 degrees; paint removal pulse: 60% -70%; welding force: 4.5N-6.5N; pulse amplitude: 155mV-170 mV; pulse width: 11mS-14 mS;

(4) carrying out secondary welding treatment on the welding spots by using high-temperature tin wires; the welding spot is required to be smooth and round, and the height of the welding spot cannot exceed 1.5 mm; the welding temperature is as follows: 390 +/-10 ℃;

(5) fixing the magnetic ring on the printed circuit board by using white silica gel; naturally drying the silica gel for more than 24 hours;

(6) packaging with white epoxy resin with shearing force being greater than or equal to 20N/mm and a white ceramic shell; curing temperature of epoxy resin: 125 ℃, curing time: for 90 minutes.

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