A high-precision dual-channel photocoupler

Abstract

The invention discloses a high-precision dual-channel optocoupler, comprising a first bracket and a second bracket, wherein an infrared receiving photosensitive triode chip is fixed on the first bracket; two infrared light-emitting diode chips are installed on the second bracket; a bonding wire is provided between the welding pad of the infrared receiving photosensitive triode chip and the welding point position of the first bracket, and secondary welding of two welding points on a single base island is formed; the first bracket is bent relative to the second bracket to form a direct-facing arrangement of two infrared light-emitting diode chips and the infrared receiving photosensitive triode chip, and a forward circuit and a reverse flip-chip circuit combination structure are formed by combining two infrared light-emitting diode chips with positive polarity and reverse polarity, and the direct-facing type greatly improves the light conversion efficiency of the facing light, facilitates the effective control of the light power of the transmitting chip, helps to improve the consistency of the dual-channel conversion efficiency, and solves the problem that the existing dual-chip must have a dual base island bracket structure and cannot form direct facing.

Description

[Technical field]

[0001] The invention relates to a photoelectric coupler technology, and in particular to a high-precision dual-channel photoelectric coupler. [Background technology]

[0002] Optocoupler is a device that encapsulates infrared light emitting device, infrared light receiving device and signal processing circuit in the same tube shell. When the input electrical signal is added to the input light emitting device LED, the LED emits light, the light receiving device receives the light signal and converts it into an electrical signal, and then directly outputs the electrical signal, or amplifies the electrical signal and processes it into a standard digital level output, thus realizing the "electric-optical-electrical" conversion and transmission. Light is the medium of transmission, so the input and output ends are electrically insulated, also known as electrical isolation.

[0003] Existing optocouplers, such as optocoupler 814 products, such as Figure 1 As shown, it is generally composed of two transmitting chips 1' with infrared light-emitting diodes and a receiving chip 2' with a phototransistor. The two transmitting chips 1' are respectively installed on a transmitting bracket 3' with a double base island on one side, and the receiving chip 2' is installed on a receiving bracket 4' on the other side. Such a structure will inevitably cause the offset of the opposite beam after bending and forming; and, as Figure 2 The polarity diagram of the infrared emission chip shown in the figure, in the existing photoelectric coupler 814 product, in the subsequent metal conductive contact surface, the N pole of the chip is generally used as the back gold surface 5', and the P pole of the chip is used as the pad surface 6'. In addition, in the existing photoelectric coupler 814 product, the emission chip 1' of the infrared light emitting diode, such as Figure 1 and Figure 3 As shown, at the transmitting end, the double-base island structure of the transmitting end is bonded and then welded to form a positive and negative dual-channel energized to emit light to control the receiving chip 2' of the photosensitive transistor at the receiving end to be turned on.

[0004] Due to the limitations of the above product structure, the production of the existing optocoupler 814 product must develop an independent and dedicated dual-island bracket and match it with corresponding related equipment and fixtures such as solid crystal, welding wire, and dispensing. However, the market application scale of the existing optocoupler 814 product is limited, resulting in production problems such as excessive investment and low equipment utilization efficiency; at the same time, the dual-channel optocoupler 814 product under the existing technical conditions, due to the influence of the dual-channel structural design factors, causes the offset of the opposite beam after bending and forming, which inevitably requires the opposite beam between the transmitting chip 1' and the receiving chip 2' to form light transmission through the refraction of epoxy resin, which results in low light conversion efficiency, low reaction sensitivity, and large chip size, which correspondingly leads to large errors in the conversion efficiency of the forward and reverse channels, and easily causes production problems such as uncontrollable quality control. It is urgent to improve the structure of the existing optocoupler 814 product. [Summary of the invention]

[0005] The present invention provides an optocoupler internal connection suitable for the optocoupler 814, which adopts a direct opposite-beam type to greatly improve the opposite-beam light conversion efficiency and has a small-volume high-precision dual-channel optocoupler.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A high-precision dual-channel photoelectric coupler comprises a first bracket and a second bracket, wherein an infrared receiving photosensitive triode chip for receiving infrared light is fixedly mounted at the center of the base island surface of the first bracket, and a bonding wire is arranged between the soldering pad of the infrared receiving photosensitive triode chip and the soldering point position of the first bracket;

[0008] Two infrared light emitting diode chips arranged in parallel and used for emitting infrared light are fixed at the center of a single base island surface of the second bracket;

[0009] When two infrared light-emitting diode chips are fixed on the base island surface, the P pole and N pole of one infrared light-emitting diode chip correspond to the solder pad surface and the back gold surface in the forward direction respectively, and the P pole and N pole of the other infrared light-emitting diode chip correspond to the back gold surface and the solder pad surface in the reverse direction respectively, and form a reverse circuit flip-chip structure with the P pole as the back gold surface and the N pole as the solder pad surface, and the forward and reverse solder pad surfaces and the back gold surfaces of the P poles and N poles of the two infrared light-emitting diode chips are interchanged to form a positive polarity and reverse polarity infrared emission chip combination;

[0010] Bonding wires are respectively provided between the soldering pads of the two infrared light emitting diode chips and the soldering point positions of the second bracket;

[0011] The first bracket is bent relative to the second bracket to form two infrared light emitting diode chips and an infrared receiving photosensitive triode chip that are directly arranged to radiate each other.

[0012] Furthermore, the two infrared light emitting diode chips are GaAs infrared light emitting diode chips made of the same material, which effectively ensures the consistency of electrical performance parameters of the bidirectional circuit, such as leakage, withstand voltage and voltage drop.

[0013] Furthermore, the welding pads of the two infrared light emitting diode chips are welded to the two welding points on the second bracket in a one-to-one correspondence to form a secondary welding of the two welding points on a single base island.

[0014] Furthermore, the infrared receiving photosensitive triode chip and the infrared light emitting diode chip are respectively fixed on their respective base island surfaces by conductive silver glue.

[0015] Furthermore, the bonding wires on the infrared receiving photosensitive triode chip and the infrared light emitting diode chip are bonded by ultrasonic welding respectively.

[0016] Furthermore, the two infrared light emitting diode chips are directly wrapped and fixed with silica gel at one time by using a needle to vertically spit glue on the base island surface of the second bracket.

[0017] The beneficial effects of the present invention are:

[0018] In the photoelectric coupler of the present invention, in order to solve the technical problems existing in the photoelectric coupler 814 product, a first bracket is bent relative to a second bracket to form two infrared light-emitting diode chips and an infrared receiving photosensitive transistor chip that are directly facing each other. When the two infrared light-emitting diode chips are fixed on the base island surface, the P pole and N pole of one infrared light-emitting diode chip correspond to the welding pad surface and the back gold surface in the forward direction, respectively, and the P pole and N pole of the other infrared light-emitting diode chip correspond to the back gold surface and the welding pad surface in the reverse direction, respectively, to form a reverse circuit flip-chip structure with the P pole as the back gold surface and the N pole as the welding pad surface; the forward and reverse welding pad surfaces and the back gold surfaces of the P poles and N poles of the two infrared light-emitting diode chips are interchanged to form an infrared emitting chip combination with positive polarity and reverse polarity, forming a single base island frame arrangement combination to replace the double base island bracket arrangement combination, and adopting a direct facing type to greatly improve the light conversion efficiency of the facing type. The direct facing combination structure can effectively control the optical power of the emitting chip, which is helpful to improve the consistency of the dual-channel conversion efficiency.

[0019] Moreover, by welding the welding pads of the two infrared light emitting diode chips to the two welding points on the second bracket one by one, secondary welding of the two welding points on a single base island is formed, so that the two infrared light emitting diode chips and the infrared receiving photosensitive transistor chip are directly arranged to face each other, and directly face the receiving end chip to achieve the purpose of direct facing, which completely solves the problem that the existing dual-chip bracket structure must have a dual base island and cannot form direct facing problems.

[0020] In addition, the structural design of the application can make the process of optocoupler 814 completely consistent with that of optocoupler 817, so that the equipment of the two products is completely universal, the main raw materials are completely unified, there are no process barriers and no equipment capital investment is required. Only the basic process programs such as conventional die bonding position program setting, wire bonding position program setting, glue dispensing position program setting, and electrical performance test program setting need to be added as backup, which can greatly reduce the production and manufacturing costs of optocoupler 814.

Brief Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the enlarged structure of the photoelectric coupler 814 after bending and forming in the prior art;

[0022] Figure 2 It is a schematic diagram of the enlarged structure of the polarity of the conventional infrared emission chip of the photoelectric coupler 814 in the prior art;

[0023] Figure 3 It is a schematic diagram of a die-bonding plane amplification structure of a double base island structure of an optocoupler 814 in the prior art;

[0024] Figure 4 It is a schematic diagram of the enlarged structure of the photoelectric coupler of the present invention after being bent and formed and directly projected;

[0025] Figure 5 It is a schematic diagram of the polarity amplification structure when an infrared light emitting diode chip in the photoelectric coupler of the present invention is flipped;

[0026] Figure 6 It is a schematic diagram of the enlarged structure of the solid crystal plane of the single base island structure of the photoelectric coupler of the present invention. [Specific implementation method]

[0027] 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.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0029] A high-precision dual-channel optocoupler suitable for the internal optocoupler structure of the optocoupler 814, such as Figures 4 to 6 As shown, it comprises a first bracket 1 and a second bracket 2, wherein an infrared receiving photosensitive triode chip 3 for receiving infrared light is fixedly installed at the center position of the base island surface of the first bracket 1; two infrared light emitting diode chips (4, 5) arranged in parallel and for emitting infrared light are fixed at the center position of the base island surface of the second bracket 2, and the infrared light emitting diode chips (4, 5) are GaAs infrared light emitting diode chips made of the same material, which can effectively ensure the consistency of electrical performance parameters of the bidirectional circuit, such as the consistency of electrical performance parameters of leakage, withstand voltage and voltage drop; a bonding wire 6 is arranged between the welding pad of the infrared receiving photosensitive triode chip 3 and the welding point position of the first bracket 1, and a bonding wire 6 is respectively arranged between the welding pads of the two infrared light emitting diode chips (4, 5) and the welding point position of the second bracket 2, wherein the welding pads of the two infrared light emitting diode chips (4, 5) are welded to two welding points on the second bracket 2 in a one-to-one correspondence manner to form secondary welding of two welding points on a single base island.

[0030] Continue as Figures 4 to 6 As shown, when two infrared light emitting diode chips (4, 5) are fixed on the base island surface, the P pole and N pole of one infrared light emitting diode chip 4 are respectively in the positive direction corresponding to the pad surface and the back gold surface (such as in the prior art) Figure 2 as shown); Figure 5 As shown, the P pole and N pole of another infrared light emitting diode chip 5 are respectively reversely flipped to the corresponding back gold surface 7 and pad surface 8, and a reverse circuit flip-chip structure is formed with the P pole as the back gold surface 7 and the N pole as the pad surface 8. The positive and negative pad surfaces and back gold surfaces of the P poles and N poles of the two infrared light emitting diode chips (4, 5) are interchanged to form a positive polarity and a reverse polarity infrared emitting chip combination.

[0031] During processing, the infrared receiving photosensitive triode chip 3 and the infrared light emitting diode chip (4, 5) are respectively fixed on their respective base island surfaces by conductive silver glue; wherein, the bonding wires 6 on the infrared receiving photosensitive triode chip 3 and the infrared light emitting diode chip (4, 5) are respectively bonded by ultrasonic welding; and on the base island surface of the second bracket 2, the two infrared light emitting diode chips (4, 5) are directly wrapped and fixed with silica gel at one time by using a needle to vertically spit glue; then, the first bracket 1 is bent relative to the second bracket 2 by using a bending mold to form a facing state package, and then after the package electroplating is completed, a mold is used to form an independent product. When testing the product, a 5000V high voltage and a current of ≤20uA are used to perform a 2s safety withstand voltage test. In the electrical performance test, a CTR value test under the reverse input state of VF=-5mA is added, and compared with the CTR value setting under the forward input state of VF=5mA, the setting error is ≤100, and the defective products in the product are effectively eliminated.

[0032] The design structure of the dual-channel photoelectric coupler is suitable for the production and processing of the photoelectric coupler 814. It utilizes the combination of two infrared light-emitting diode chips (4, 5) with positive polarity and reverse polarity to form a reverse circuit flip-chip structure. The direct opposite-direction type greatly improves the opposite-direction light conversion efficiency, facilitates the effective control of the light power of the emission chip, helps to improve the consistency of the dual-channel conversion efficiency, and solves the problem that the existing dual-chip must have a dual-base island bracket structure and cannot form direct opposite-direction.

[0033] The above-described embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. All equivalent changes made based on the shape, structure and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-precision dual-channel photoelectric coupler, characterized in that: comprising a first bracket and a second bracket, An infrared receiving photosensitive triode chip for receiving infrared light is fixedly mounted at the center of the base island surface of the first bracket, and a bonding wire is provided between the soldering pad of the infrared receiving photosensitive triode chip and the soldering point of the first bracket; Two infrared light emitting diode chips arranged in parallel and used for emitting infrared light are fixed at the center of a single base island surface of the second bracket; When two infrared light-emitting diode chips are fixed on the base island surface, the P pole and N pole of one infrared light-emitting diode chip correspond to the solder pad surface and the back gold surface in the forward direction respectively, and the P pole and N pole of the other infrared light-emitting diode chip correspond to the back gold surface and the solder pad surface in the reverse direction respectively, and form a reverse circuit flip-chip structure with the P pole as the back gold surface and the N pole as the solder pad surface, and the forward and reverse solder pad surfaces and the back gold surfaces of the P poles and N poles of the two infrared light-emitting diode chips are interchanged to form a positive polarity and reverse polarity infrared emission chip combination; Bonding wires are respectively provided between the soldering pads of the two infrared light emitting diode chips and the soldering point positions of the second bracket; The first bracket is bent relative to the second bracket to form two infrared light emitting diode chips and an infrared receiving photosensitive triode chip that are directly arranged to radiate each other; The two infrared light emitting diode chips are GaAs infrared light emitting diode chips made of the same material; The pads of the two infrared light emitting diode chips are respectively welded to the two welding points on the second bracket in a one-to-one correspondence to form a secondary welding of two welding points on a single base island; The infrared receiving photosensitive triode chip and the infrared light emitting diode chip are respectively fixed on their respective base island surfaces by conductive silver glue; The bonding wires on the infrared receiving photosensitive triode chip and the infrared light emitting diode chip are respectively bonded by ultrasonic welding; The second bracket uses a needle to vertically spit glue on the base island surface to directly wrap and fix two infrared light emitting diode chips with silicone at one time.

Images