CN216122382U - Photoelectric coupler - Google Patents

Abstract

The embodiment of the application provides a photoelectric coupler, and belongs to the technical field of photoelectricity. The photoelectric coupler comprises a base, a shell, a light emitter, a light receiver and a resistor; wherein, the shell and the base form a closed space; the light emitter, the light receiver and the resistor are positioned in the closed space; the light receiver comprises at least two cascaded triodes, wherein the preceding triode is a phototriode, and the phototriode and the light emitter form optical coupling; and a resistor is connected between the emitter of the phototriode and the emitter of the final triode. According to the photoelectric coupler, the emitting electrode of the photoelectric triode and the emitting electrode of the final triode are connected through the resistor to release leakage current, and current misconduction caused by the increase of the leakage current at high temperature is prevented.

Description

Photoelectric coupler

Technical Field

The application relates to the field of photoelectric technology, in particular to a photoelectric coupler.

Background

A photocoupler, also called a photo isolator or a photocoupler, called a photocoupler for short, is a device that transmits electrical signals by using light as a medium, and generally packages a light emitter (such as a light emitting diode chip) and a light receiver (such as a photosensitive chip) in the same cavity, and divides the light path transmission process into an input end and an output end. When an electric signal is applied to the input end, the light emitter emits light, and the light receiver receives the light to generate an electric signal, so that 'electricity-light-electricity' conversion is realized. Because the input and the output of the photoelectric coupler are isolated from each other, the electric signal transmission has the characteristics of unidirectionality and the like, so the photoelectric coupler has good electric insulation and anti-interference capability, and is widely applied to various circuits such as a switch circuit, a logic circuit, a high-voltage stabilizing circuit and the like.

Modern electronic power demands increasingly higher device reliability and also puts higher demands on the performance of optoelectronic couplers. The photoelectric coupler products on the market are easy to have unstable performance when used in a high-temperature environment of more than 100 ℃, have low reliability and are difficult to meet the requirement of normal work of power electronics in a large temperature range.

SUMMERY OF THE UTILITY MODEL

To above-mentioned technical problem, the application provides a photoelectric coupler, satisfies the user demand under the high temperature environment.

In order to achieve the above object, the present application provides a photoelectric coupler, including a base, a housing, a light emitter, a light receiver, and a resistor;

wherein, the shell and the base form a closed space; the light emitter, the light receiver and the resistor are positioned in the closed space;

the light receiver comprises at least two cascaded triodes, wherein the preceding triode is a phototriode, the phototriode and the light receiver form optical coupling, and the resistor is connected between the emitter of the phototriode and the emitter of the last triode.

Optionally, the light receptor is of darlington construction.

Optionally, the light-receiving surface is taken as the front surface, the light-receiving surface of the light receiver is provided with a first electrode, a second electrode and a third electrode, and the back surface is provided with a fourth electrode, wherein:

the first electrode is a common electrode of an emitting electrode of the front-stage phototriode and a base electrode of the rear-stage phototriode;

the second electrode is an emitting electrode of the rear triode;

the third electrode is the base electrode of the preceding triode;

the fourth electrode is a common electrode of the collector of the preceding triode and the collector of the rear triode.

Optionally, a plurality of metalized areas isolated from each other are arranged on the end surface of the base facing the housing, and the metalized areas include a first metalized area, a second metalized area, a third metalized area and a fourth metalized area;

the light emitter is fixed on the fourth metalized area, the negative electrode of the light emitter is electrically connected with the first metalized area, and the positive electrode of the light emitter is electrically connected with the fourth metalized area;

the light receiver is fixed on the third metalized area, and a collector of a preceding-stage triode in the light receiver is electrically connected with the third metalized area;

the resistor is fixed on the fourth metalized area, and one end of the resistor, which is connected with the rear triode of the light receiver, is electrically connected with the second metalized area.

Optionally, the shapes of the third and fourth metalized regions are independently selected from "I", "T", or "L".

Optionally, a distance between two adjacent metalized areas in the plurality of metalized areas is greater than or equal to 0.3 mm.

Optionally, the base further includes a plurality of pins, one end of each pin is electrically connected to the corresponding metalized region, and the other end of each pin extends from the end surface of the base facing away from the housing.

Optionally, the photocoupler further includes a light guiding glue through which the light emitter and the light receiver form a reflective coupling.

Optionally, the light guiding glue is semi-ellipsoidal.

Optionally, the base includes a base, wherein an insulator is disposed in a middle of an end surface of the base facing the housing, and a plurality of metalized regions are disposed on an end surface of the insulator facing the housing; the edge of the end face of the base facing the shell is connected with the shell in a sealing mode.

In the photoelectric coupler that this application embodiment provided, the light receiver includes two at least cascaded triodes, the preceding stage triode is the phototriode, set up bleeder resistance between the emitter of the preceding stage phototriode of light receiver and the emitter of final stage triode, prevent that high temperature leakage current from making follow-up circuit misleading, make photoelectric coupler keep comparatively stable performance under the high temperature environment more than 100 ℃, satisfy the demand that electronic power normally worked in great temperature range (for example 55 ℃ to 125 ℃) below zero.

Drawings

Fig. 1 is a perspective view of an alternative structure of a photocoupler provided in an embodiment of the present application;

fig. 2 is a top view of an alternative structure of a photocoupler provided in an embodiment of the present application;

fig. 3 is a side view of an alternative structure of a photocoupler provided in an embodiment of the present application;

fig. 4 is a schematic circuit diagram of a photoelectric coupler provided in the embodiment of the present application.

The reference numerals in the drawings denote:

1-a base; 2-a housing; 3-a light emitter; 4-a light receptor; 5-resistance; 6-light guide glue; 7-a raised structure;

11-a first metalized area; 12-a second metalized area; 13-a third metalized area; 14-a fourth metalized region; 15-a first pin; 16-a second pin; 17-a third pin; 18-fourth pin.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more clearly understood, the technical solutions of the present application are described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the following description of specific embodiments is merely illustrative of the present application and is not intended to limit the present application. Rather, the present application may be embodied in many different forms and is not limited to the embodiments described herein. The features in the embodiments described below may be combined with each other without conflict.

It should be noted that when one component is referred to as being "connected" or "electrically connected" to another component, it may be directly connected or electrically connected to the other component, or may be connected or electrically connected by means of the other component.

In the prior art, a light receiver of a photoelectric coupler mostly adopts a phototriode to receive a light signal and convert the light signal into an electric signal, and at a temperature of 100 ℃ and above, a leakage current ICEO between a collector and an emitter of the phototriode is increased to cause unstable transmission performance, and the leakage current ICEO is easy to cause misconduction of a subsequent circuit, so that the requirement of normal operation of modern electronic power in a large temperature range (for example, minus 55 ℃ to 125 ℃) is difficult to meet.

In view of the above problems, the present embodiment provides a photocoupler, as shown in fig. 1 to 3, including a base 1, a housing 2, a light emitter 3, a light receiver 4, and a resistor 5.

Wherein, base 1 and shell 2 sealed cooperation form airtight space, and illuminator 3, photic ware 4 and resistance all are located airtight space, and form the optical coupling between illuminator 3 and the photic ware 4, and illuminator 3 receives the signal of telecommunication and converts the light signal promptly, and photic ware 4 receives the light signal, and converts the signal of telecommunication output into. In this embodiment, the light receiver 4 includes at least two cascaded triodes, wherein the preceding triode is a photo-triode, and the photo-triode forms an optical coupling with the light emitter 3; the emitter of the preceding triode (i.e. the phototriode) is connected with the emitter of the final triode through a resistor 5.

In the working process of the photoelectric coupler, the phototriodes receive optical signals and convert the optical signals into amplified electric signals, and at least one triode cascaded with the phototriodes further amplifies the electric signals. Therefore, the optical receiver 4 amplifies the electrical signal at least twice, and the current transfer ratio can reach 3000% or more. In the process, the emitter of the phototriode is connected with the emitter of the final-stage triode through the resistor 5 to form a discharge current leakage channel, so that the phenomenon that leakage current ICEO generated by the phototriode at high temperature enters the rear-stage triode to generate misconduction is prevented. Further, the resistor 5 may also be grounded, that is, one end of the resistor 5 is connected to the emitter of the phototransistor, and the other end is connected to the emitter of the last triode and grounded. It should be understood that the final triode refers to the last triode in the latter triode of the light receiver 4.

Preferably, with further reference to fig. 4, the light receiver 4 is in a darlington configuration, which includes two cascaded transistors, wherein the preceding transistor is a photo transistor. The collector of the preceding triode is connected with the collector of the rear triode to serve as an output end, the emitter of the preceding triode is connected with the base of the rear triode, one end of the resistor is connected with the emitter of the preceding triode, and the other end of the resistor is connected with the emitter of the rear triode to serve as another output end.

A closed space is formed by the housing 2 and the base 1, wherein the light emitter 3, the light receiver 4, and the resistor 5 are located in the closed space. The shell 2 can protect the components and circuits inside the photoelectric coupler, can shield light outside the photoelectric coupler, and avoids interference of external light on signal transmission between the light emitter 3 and the light receiver 4.

Specifically, the optical coupling of the light emitter 3 and the light receiver 4 includes a correlation optical coupling and a reflection optical coupling. In an optional implementation manner, the photoelectric coupler provided in the embodiment of the present application further includes a light guiding glue 6, the light emitter 3 and the light receiver 4 are wrapped by the light guiding glue 6, and light emitted by the light emitter 3 is transmitted in the light guiding glue 6. The insulating property of the light guide glue 6 is superior to that of nitrogen, and higher isolation voltage can be obtained by wrapping the light guide glue 6. Preferably, the light emitter 3 and the light receiver 4 are coupled in a reflective manner by the light guiding glue 6, which not only increases the isolation voltage of the photocoupler, but also reduces the size of the photocoupler compared with the coupling in a counter light manner.

With further reference to fig. 3, a light guiding glue 6 covers the end face of the base 1. In some exemplary embodiments, the light emitted from the light emitter 3 is reflected at the boundary of the light guiding glue 6 and received by the light receiver 4, i.e. the light guiding glue 6 provides a channel of the light path. In an alternative embodiment, as shown in fig. 3, the light guiding glue 6 is semi-ellipsoidal, and the light emitted from the light emitter 3 is reflected at the boundary of the light guiding glue 6, so that the light emitted from the light emitter 3 is concentrated into the semi-ellipsoid as much as possible, thereby reducing the light dissipated into the air. It should be understood that the semi-sphere is also a form of semi-ellipsoid, and those skilled in the art can select the shape of the light guiding glue 6 according to actual requirements. In yet another alternative embodiment, the space between the light guiding glue 6 and the housing 2 is filled with a protective substance, such as nitrogen.

The base 1 has a plurality of metallized areas that can be used to mount components and can also be used as electrodes. In order to reduce the size of the photocoupler, the distance between the metalized regions on the base 1 should be reduced as much as possible. However, since a plurality of metalized areas are used as electrodes, the distance between each other cannot be reduced without limitation. And, the distance between the plurality of metalized areas on the base 1 is determined by the specific application circuit of the photocoupler, and theoretically, the farther the distance is, the higher the isolation voltage of the photocoupler is. In the preferred embodiment of the application, the distance between the metalized areas is greater than or equal to 0.3mm, so that the isolation voltage of the photoelectric coupler is not lower than 2000V.

In an exemplary embodiment, as shown in fig. 2, the end surface of the base 1 facing the housing 2 is provided with a first metalized area 11, a second metalized area 12, a third metalized area 13 and a fourth metalized area 14, which are isolated from each other. The cathode of the light emitter 3 is electrically connected to the first metallization region 11 and the anode is electrically connected to the fourth metallization region 14. The collector of the preceding triode and the collector of the following triode in the light receiver 4 are both electrically connected with the third metalized region 13. Of the two ends of the resistor 5, one end is electrically connected to the emitter of the preceding stage phototransistor in the light receiver 4, the other end is electrically connected to the emitter of the final stage triode in the light receiver 4, and the other end of the resistor 5 is further electrically connected to the second metalized area 12.

Illustratively, as shown in fig. 1 and 2, the resistor 5 is a chip resistor, one side of which is connected to the fourth metalized area 14 through an insulating adhesive, and the other side of which is electrically connected to the light receiver 4 through a bonding wire.

The specific type of the light emitter 3 is not particularly limited in this embodiment, and may be a light emitting device commonly used in an existing optical coupler, such as a Light Emitting Diode (LED). Illustratively, the positive electrode and the negative electrode of the light emitter 3 are respectively disposed on the front surface (light emitting surface) of the light emitter 3 and the back surface of the light emitting surface, so that the light emitter 3 can be bonded to the fourth metalized region 14 of the base 1 through a conductive adhesive, and the negative electrode of the light emitter 3 can be electrically connected to the fourth metalized region 14 while the mounting structure stability of the light emitter 3 is ensured.

Similarly, the light receptor 4 is adhered to the third metalized area 13 of the submount 1. Taking the example where the light receiver 4 adopts the darlington structure, in some examples, the front surface (light receiving surface) of the light receiver 4 is provided with a first electrode, a second electrode, and a third electrode, and the back surface of the light receiving surface 4 is provided with a fourth electrode. The first electrode is a common electrode of a front-stage phototriode emitter and a rear-stage triode base of the light receiver 4; the second electrode is an emitting electrode of a rear triode of the light receiver 4; the third electrode is the base electrode of the preceding stage photoelectric triode; the fourth electrode is a common electrode of a collector electrode of the preceding stage photoelectric triode and a collector electrode of the rear stage triode. The back surface of the light receiver 4 is fixed to the third metalized area 13 through a conductive adhesive, so that the fourth electrode of the light receiver 4 is electrically connected to the third metalized area 13.

The third electrode can be used for supplementary input, namely the function of the third electrode is similar to that of an enabling end, and the third electrode can be led out or reserved. For example, when the third electrode is not drawn out, it can be used as a supplementary input so that the photocoupler can be used as a normal triode when there is no light. When the third electrode needs to be led out, a metalized area and a pin corresponding to the metalized area can be added on the base 1.

Optionally, the shapes of the third and fourth metallisation regions 13, 14 are independently selected from "I", "T" or "L", i.e. the shapes of the third and fourth metallisation regions 13, 14 may be the same or different. Preferably, the third and fourth metalized regions 13, 14 are oppositely "L" shaped to provide a location for mounting components.

As described above, the base 1 and the housing 2 are hermetically fitted to accommodate the light emitter 3, the light receiver 4, and the resistor 5. The shape, size and material of the base 1 and the housing 2 are different according to the type of the package. Those skilled in the art will readily select the appropriate package type for a particular application circuit. In some examples, the base 1 comprises a base, wherein the base is provided with an insulator, such as a glass insulator, in the middle of the end surface of the base facing the housing 2, and the end surface of the insulator facing the housing 2 is provided with a plurality of metalized areas; the edge of the end face of the base facing the housing 2 is hermetically connected to the housing 2, and the housing 2 accommodates the insulator and the light emitter 3, the light receiver 4, the resistor 5, and the like on the insulator. Wherein, the base and the shell 2 are made of metal materials and are connected by energy storage welding.

In a further development, the base 1 has a raised structure 7 for positioning, which may in particular be arranged on the side circumference of the base.

As shown in fig. 1, the base 1 further includes a plurality of pins, and the plurality of pins correspond to the plurality of metallization regions respectively; for convenience of distinction, the plurality of pins are labeled as a first pin 15, a second pin 16, a third pin 17, and a fourth pin 18, wherein the first pin 15 corresponds to the first metalized region 11, the second pin 16 corresponds to the second metalized region 12, the third pin 17 corresponds to the third metalized region 13, and the fourth pin 14 corresponds to the fourth metalized region 14. One end of each pin is electrically connected with the corresponding metalized area, and the other end of each pin is used for establishing electrical connection with an external circuit. Illustratively, the other ends of the plurality of pins are led out from the side surface of the base 1, or the other ends of the plurality of pins are led out from the end surface of the base 1 facing away from the housing 2.

In the embodiments of the present application, only a Transistor Outline (TO) package is taken as an example, and the example embodiments are as follows.

Examples

In an exemplary embodiment, as shown in fig. 1 to 4, a photocoupler provided in an example of the present application includes a base 1, a case 2, a light emitter 3, a light receiver 4, a resistor 5, and a light guide adhesive 6.

The housing 2 and the base 1 form a closed space, wherein the light emitter 3, the light receiver 4, the resistor 5 and the light guide glue 6 are located in the closed space.

As shown in fig. 1 and 2, four metalized areas, namely a first metalized area 11, a second metalized area 12, a third metalized area 13 and a fourth metalized area 14, are provided on the end surface of the base 1 facing the housing 2; four pins are arranged in the base 1 and are divided into a first pin 15, a second pin 16, a third pin 17 and a fourth pin 18. One end of each of the four pins is correspondingly connected with the corresponding metallized area, and the other end of each of the four pins extends out of the other side end face of the base 1 and is used for establishing electrical connection with an external circuit. Preferably, the first through fourth pins 15-18 are gold-plated with kovar metal.

The third metallised region 13 is for mounting the light receptor 4 and the fourth metallised region 14 is for mounting the light emitter 3 and the resistor 5. In order to ensure that the isolation voltage of the optocoupler is greater than or equal to 2000V, the distance between the third metalized region 13 and the fourth metalized region 14 is greater than or equal to 0.3 mm. In a specific implementation, the third metalized region 13 and the fourth metalized region 14 are opposite L-shaped to provide positioning for mounting components.

As shown in fig. 1 and 2, the negative electrode of the light emitter 3 is arranged at the light emitting surface, i.e. the negative electrode of the light emitter 3 is arranged at the front surface, connected to the first metalized area 11 by means of a bonding wire. The anode of the light emitter 3 is arranged on the back side, and the back side of the light emitter 3 can be adhered to the fourth metalized area 14 through conductive adhesive, so that the anode of the light emitter 3 is electrically connected with the fourth metalized area 14 while the fixation is realized. The external circuitry applies electrical signals to the cathode and anode of the light emitter 3 through the first pin 15 (and first metallised region 11) and the fourth pin 18 (and fourth metallised region 14).

The light receiver 4 is of a darlington structure, a front stage transistor of the darlington structure is a photo transistor, and a circuit diagram of the front stage transistor can refer to fig. 4. Specifically, the emitter of the preceding triode is connected with the base of the following triode, the collector of the preceding triode is connected with the collector of the following triode, and a resistor 5 is connected between the emitter of the preceding triode and the emitter of the following triode.

In some examples, the light receiver 4 has a light receiving surface provided with a first electrode, a second electrode, and a third electrode, and a back surface of the light receiving surface provided with a fourth electrode. The first electrode is a common electrode of an emitting electrode of the front-stage phototriode and a base electrode of the rear-stage phototriode; the second electrode is an emitting electrode of the rear triode; the third electrode is the base electrode of the preceding stage photoelectric triode; the fourth electrode is a common electrode of the collector of the preceding stage photoelectric triode and the collector of the rear stage triode. The first electrode and the second electrode are respectively and electrically connected with two ends of the resistor 5 through the compression welding wires, the third electrode is used as an enabling end, and the fourth electrode is connected to the third metalized area 13 through the conductive adhesive.

One end of the resistor 5 is electrically connected with the emitter of the preceding stage phototriode of the light receiver 4, and the other end of the resistor 5 is electrically connected with the emitter of the following stage phototriode. The resistor 5 may be a chip resistor, one surface of which is fixed on the fourth metalized area 14 through an insulating adhesive, and the other surface of which is electrically connected with the light receiver 4 through a bonding wire.

The light guide glue 6 is semi-ellipsoidal, and the light emitter 3, the light receiver 4 and the resistor 5 are wrapped by the light guide glue 6, so that the light emitter 3 and the light receiver 4 form reflective coupling.

To sum up, in the photoelectric coupler provided by the embodiment of the present application, the light receiver includes at least two cascaded stages of triodes, wherein the triode is used as a preceding stage triode, and a resistor is connected between an emitter and a final stage triode, thereby forming a leakage channel, avoiding the increase of leakage current generated by the triode in a high temperature (for example, above 100 ℃) environment to cause the misconduction of a subsequent circuit, and meeting the use requirement of normal work of power electronics in a large temperature range (for example, 55 ℃ below zero to 125 ℃).

In addition, the light receiver of the photoelectric coupler adopts multistage cascade triodes (such as a Darlington structure) to amplify signals for multiple times, so that the current transmission ratio can reach more than 3000%, and the high current transmission ratio is realized.

The utility model provides a photoelectric coupler adopts TO type encapsulation form, and its illuminator and photic ware are located same mounting plane, make photoelectric coupler have less volume.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims (10)

1. A photoelectric coupler is characterized by comprising a base (1), a shell (2), a light emitter (3), a light receiver (4) and a resistor (5);

wherein the shell (2) and the base (1) form a closed space; the light emitter (3), the light receiver (4) and the resistor (5) are positioned in the closed space;

the light receiver (4) comprises at least two cascaded triodes, wherein the preceding triode is a phototriode, the phototriode and the light emitter (3) form optical coupling, and the resistor (5) is connected between the emitter of the phototriode and the emitter of the last triode.

2. Photocoupler according to claim 1, characterized in that the light receiver (4) is of darlington construction.

3. The photocoupler according to claim 2, wherein the light-receiving surface is a front surface, the front surface of the light-receiving element (4) is provided with a first electrode, a second electrode and a third electrode, and the back surface is provided with a fourth electrode, wherein:

the first electrode is a common electrode of an emitting electrode of the front-stage triode and a base electrode of the rear-stage triode;

the second electrode is an emitting electrode of the rear triode;

the third electrode is a base electrode of the preceding triode;

and the fourth electrode is a common electrode of a collector electrode of the preceding triode and a collector electrode of the rear triode.

4. Optoelectronic coupler according to claim 2 or 3, characterized in that the end face of the base (1) facing the housing (2) is provided with a plurality of metallized regions isolated from one another, including a first metallized region (11), a second metallized region (12), a third metallized region (13) and a fourth metallized region (14);

the light emitter (3) is fixed on the fourth metalized area (14), the negative electrode of the light emitter (3) is electrically connected with the first metalized area (11), and the positive electrode of the light emitter (3) is electrically connected with the fourth metalized area (14);

the light receiver (4) is fixed on the third metalized area (13), and a collector of a preceding triode in the light receiver (4) is electrically connected with the third metalized area (13);

the resistor (5) is fixed on the fourth metalized area (14); one end of the resistor (5) connected with the rear triode of the light receiver (4) is electrically connected with the second metalized area (12).

5. Photocoupler according to claim 4, characterized in that the shape of said third metalized region (13) and said fourth metalized region (14) are independently selected from "I", "T" or "L".

6. The photocoupler of claim 4, wherein the distance between two adjacent metalized areas in the metalized areas is greater than or equal to 0.3 mm.

7. Photocoupler according to claim 4, characterized in that base (1) further comprises a plurality of pins, each of which has one end electrically connected to a corresponding metalized area and the other end protruding from the end face of base (1) facing away from housing (2).

8. The photocoupler according to any one of claims 1 to 3, further comprising a light guiding glue (6), wherein said light emitter (3) and said light receiver (4) are reflectively coupled through said light guiding glue (6).

9. Photocoupler according to claim 8, characterized in that said light guiding glue (6) is semi-ellipsoid.

10. Photocoupler according to claim 4, characterized in that base (1) comprises a base, wherein the middle of the end face of the base facing the housing (2) is provided with an insulator, and the end face of the insulator facing the housing (2) is provided with said metallized areas; the end face edge of the base facing the shell (2) is connected with the shell (2) in a sealing mode.

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