CN219371029U - Composite structure used as AC-DC power switch and circuit thereof - Google Patents

Abstract

The utility model relates to a composite structure used as an AC-DC power switch and a circuit thereof, belonging to the technical field of power devices, wherein the composite structure comprises: the semiconductor device comprises an N+ type semiconductor substrate, an N-type epitaxial layer, a P-type doped region serving as a collector region of a first triode and a base region of a second triode, a first N+ type doped region serving as a base region of the first triode, a second N+ type doped region serving as an emitter region of the second triode, a P++ type doped region serving as an emitter region of the first triode, a plurality of metal electrodes, a dielectric layer between the metal electrodes and a collector electrode of the second triode, wherein the collector electrode is arranged on the back surface of the N+ type semiconductor substrate. When the composite structure provided by the application is conducted, the NPN triode works in a saturation region, so that the saturation voltage of the composite structure is reduced, and the conduction loss can be reduced; in addition, the PNP triode in the composite structure has higher current gain, so that the requirement for driving current of the control IC can be further reduced.

Description

Composite structure used as AC-DC power switch and circuit thereof

Technical Field

The utility model relates to the technical field of power devices, in particular to a composite structure used as an AC-DC power switch and a circuit thereof.

Background

The AC-DC system converts alternating current into direct current, has wide application in various fields of modern electronic society, adopts a high-frequency switch working transformer to replace a power frequency transformer in order to improve the energy conversion efficiency, reduces the volume of the AC-DC system and improves the energy conversion efficiency.

The switching power supply is realized through the switching operation of a high-frequency transformer, a power element is used as an electronic switch to control the operation of the transformer, different topological structures are selected, different power switching elements are required to be correspondingly designed and optimized, and the driving and control circuits of the power switching elements are all required to be correspondingly designed and optimized, wherein in the prior art, an HVBJT or a Darlington tube formed by two NPN triodes is used as the power switching element.

When the HVBJT is used as a power switching element in an AC-DC switching power supply, the HVBJT is suitable for an AC-DC system with medium and small power and is widely applied to systems such as chargers, adapters and the like with different powers, however, the current gain of the HVBJT is relatively low, generally about 30, in order to meet the requirement of certain power output, when the HVBJT outputs with 20W of full power, the on duty ratio of the HVBJT is assumed to be 20%, and when the input of the AC is the lowest voltage, according to 200V, the efficiency is estimated to be 90%, the peak current flowing through the HVBJT is about 800mA, and the maximum value of the base driving current provided by a control IC is required to be more than 100mA, so that the HVBJT can enter a saturation region; when the Darlington transistor formed by two NPN triodes is used as a power switching element in an AC-DC switching power supply, the base electrode driving current can be greatly reduced, the pressure on a driving IC is reduced, but only one NPN triode can work in a saturation region, and the other NPN triode can only work in an amplifying region, and the CE voltage drop at the moment is about 1V-1.1V, so that the conduction power consumption is relatively large, and the conversion efficiency of an AC-DC system is reduced.

Disclosure of Invention

The utility model aims to provide a composite structure used as an AC-DC power switch and a circuit thereof, so as to solve the defects in the prior art, and the technical problems to be solved by the utility model are realized by the following technical scheme.

The utility model provides a composite structure used as an AC-DC power switch, which is characterized in that the composite structure comprises:

an n+ type semiconductor substrate;

the N-type epitaxial layer is arranged above the N+ type semiconductor substrate;

the P-type doped region is arranged in the N-type epitaxial layer;

the first N+ type doped region and the second N+ type doped region are respectively arranged in the P type doped region;

the P++ type doped region is arranged in the first N+ type doped region and is used as an emitting region of the first triode;

a plurality of metal electrodes disposed over the P-type doped region, the first n+ type doped region, the second n+ type doped region, and the p++ type doped region;

a dielectric layer is arranged among the plurality of metal electrodes;

and the collector electrode of the second triode is arranged on the back surface of the N+ type semiconductor substrate.

In the above scheme, the plurality of metal electrodes include a common electrode, a base electrode of the first triode, an emitter electrode of the first triode and an emitter electrode of the second triode, the common electrode is arranged above the P-type doped region, the base electrode of the first triode is arranged above the first n+ type doped region, the emitter electrode of the first triode is arranged above the p++ type doped region, and the emitter electrode of the second triode is arranged above the second n+ type doped region.

In the above scheme, the P-type doped region is used as the collector region of the first triode and the base region of the second triode.

In the above scheme, the first n+ doped region is used as the base region of the first triode, and the second n+ doped region is used as the emitter region of the second triode.

In the above scheme, the common electrode is a collector of the first triode and a base of the second triode.

In the above scheme, the first triode is a PNP triode.

In the above scheme, the second triode is an NPN triode.

The circuit for the composite structure of the AC-DC power switch comprises the composite structure for the AC-DC power switch, and comprises the following components:

PNP and NPN transistors;

and the collector electrode of the PNP triode is electrically connected with the base electrode of the NPN triode.

The embodiment of the utility model has the following advantages:

the composite structure used as the AC-DC power switch has higher current gain, so that the current requirement for IC driving is obviously reduced, after the composite structure is adopted, the active current of the control IC is changed into the current filling of the NPN triode, the integrated driving is easier to realize, and when the composite structure is conducted, the NPN triode works in a saturation region, the saturation voltage drop of the composite structure is lower than that of a composite tube of an NPN+NPN Darlington structure, the conduction loss can be reduced, and the AC-DC conversion efficiency is improved; in addition, the PNP type triode in the composite structure can have higher current gain without being limited by the current gain of the NPN type triode, so that the requirement of driving current of the control IC can be further reduced.

Drawings

Fig. 1 is a schematic diagram of a composite structure of the present utility model for use as an AC-DC power switch.

Fig. 2 is a process diagram of forming an n+ type semiconductor substrate and an N-type epitaxial layer in accordance with the present utility model.

Fig. 3 is a process diagram of forming a P-type doped region in accordance with the present utility model.

Fig. 4 is a process diagram of forming a first n+ type doped region and a second n+ type doped region according to the present utility model.

Fig. 5 is a process diagram of forming a p++ type doped region according to the present utility model.

Fig. 6 is a process diagram of forming dielectric layers spaced apart in accordance with the present utility model.

Fig. 7 is a process diagram of forming a common electrode, a base of a first transistor, an emitter of the first transistor, and an emitter of a second transistor according to the present utility model.

Fig. 8 is a process diagram of the present utility model for forming the collector of the second transistor.

Fig. 9 is a circuit diagram of a composite structure used in a flyback AC-DC switching power supply in one embodiment of the utility model.

Detailed Description

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The utility model will be described in detail below with reference to the drawings in connection with embodiments.

As shown in fig. 1, the present utility model provides a composite structure for use as an AC-DC power switch, comprising:

an n+ type semiconductor substrate 1;

an N-type epitaxial layer 2 disposed over the n+ -type semiconductor substrate 1;

the P-type doped region 3 is arranged in the N-type epitaxial layer 2 and is used as a collector region of a first triode and a base region of a second triode, wherein the first triode is a PNP type triode, and the second triode is an NPN type triode;

the first N+ type doped region 4 and the second N+ type doped region 5 are respectively arranged in the P type doped region 3, wherein the first N+ type doped region 4 is used as a base region of the first triode, and the second N+ type doped region 5 is used as an emitter region of the second triode;

the P++ type doped region 6 is arranged in the first N+ type doped region 4 and is used as an emitting region of the first triode;

a plurality of metal electrodes arranged above the P-type doped region 3, the first n+ type doped region 4, the second n+ type doped region 5 and the p++ type doped region 6, wherein the plurality of metal electrodes comprise a common electrode 8, a base 9 of the first triode, an emitter 10 of the first triode and an emitter 11 of the second triode, the common electrode 8 is arranged above the P-type doped region 3, the base 9 of the first triode is arranged above the first n+ type doped region 4, the emitter 10 of the first triode is arranged above the p++ type doped region 6, and the emitter 11 of the second triode is arranged above the second n+ type doped region 5;

a dielectric layer 7 is arranged among the plurality of metal electrodes;

and a collector 12 of the second transistor provided on the back surface of the n+ type semiconductor substrate 1.

In this embodiment, the common electrode 8 is a collector of the first triode and a base of the second triode.

In this embodiment, the doping concentrations of the regions need to be appropriately matched, so as to meet the requirements of various parameters of the high-voltage-resistant NPN-type triode and match the current gain of the NPN-type triode; the composite structure can control the output of the control IC, thereby realizing a more economical and stable AC-DC system.

As shown in fig. 2 to 8, the preparation method of the composite structure for the AC-DC power switch provided by the utility model comprises the following steps:

step S1: preparing an N+ type semiconductor substrate 1 and an N-type epitaxial layer 2 arranged above the N+ type semiconductor substrate 1 by triple diffusion;

step S2: etching the N-type epitaxial layer 2 by using photoresist as a mask, and performing boron doping and diffusion in the etched area of the N-type epitaxial layer 2 to form a P-type doped region 3;

step S3: etching the P-type doped region 3 by using photoresist as a mask, and performing phosphorus doping and diffusion in the etched region of the P-type doped region 3 to form a first N+ type doped region 4 and a second N+ type doped region 5;

step S4: etching the first N+ type doped region 4 by using photoresist as a mask, and performing boron doping and diffusion in the etched region of the first N+ type doped region 4 to form a P++ type doped region 6;

step S5: depositing and photoetching a dielectric layer 7 which is mutually spaced above the P-type doped region 3, the first N+ type doped region 4, the second N+ type doped region 5 and the P++ type doped region 6 by adopting a CVD process;

step S6: evaporating and depositing Al between and above the dielectric layers 7, etching the evaporated and deposited Al above the P-type doped region 3 to form a common electrode 8, etching the evaporated and deposited Al above the first N+ type doped region 4 to form a base 9 of a first triode, etching the evaporated and deposited Al above the P++ type doped region 6 to form an emitter 10 of the first triode, and etching the evaporated and deposited Al above the second N+ type doped region 5 to form an emitter 11 of the second triode;

step S7: ti/Ni/Ag is deposited on the back surface of the N+ type semiconductor substrate 1 by evaporation, and a collector electrode 12 of the second triode is formed.

The present utility model provides a circuit for use as a composite structure for an AC-DC power switch, comprising a composite structure as described above for use as an AC-DC power switch, the circuit comprising:

PNP and NPN transistors;

and the collector electrode of the PNP triode is electrically connected with the base electrode of the NPN triode.

As shown in fig. 9, in one embodiment of the present utility model, the above composite structure is used in a flyback AC-DC switching power supply, using the above composite structure as a power switch, the AC-DC switching power supply comprising:

an AC-DC circuit, a feedback network, a photocoupler, a composite structure, and a control IC;

the composite structure comprises a PNP triode T1 and an NPN triode T2;

the feedback network is electrically connected with the output end of the AC-DC circuit;

the photoelectric coupler is electrically connected with the output end of the feedback network, the photoelectric coupler comprises a first output end and a second output end, the first output end is connected to the output end of the rectifier bridge in the AC-DC circuit through a resistor, and the second output end is grounded through a resistor;

the VDD pin of the control IC is electrically connected with the first output end of the photoelectric coupler, and the GND pin of the control IC is electrically connected with the second output end of the photoelectric coupler.

In this embodiment, a base electrode of the PNP transistor is electrically connected to a driving pin of the control IC, and an emitter electrode of the PNP transistor is electrically connected to a first output end of the photocoupler; the base electrode of the NPN type triode is electrically connected with the collector electrode of the PNP type triode, the emitter electrode of the NPN type triode is grounded through a resistor, and the collector electrode of the NPN type triode is connected to the output end of the rectifier bridge in the AC-DC circuit through a diode connected with the RC parallel circuit.

In this embodiment, the working voltage of the control IC is not very high, so the composite structure of the present utility model can meet the requirement of application withstand voltage; in addition, the current gain of the PNP type triode in the composite structure can be relatively high and is not limited by the current gain of the NPN type triode, so that the requirement for controlling the driving current of the IC can be further reduced.

In this embodiment, the magnitude of the driving current of the actual control IC should be adjusted according to the actual current gain of the PNP transistor, if the current gain of the PNP transistor is 100 times, the driving current only needs 1-2mA on the assumption of the same AC-DC technical index; the NPN triode works in a saturation region when being conducted, and under reasonable design and working conditions, the saturation voltage drop of the NPN triode can be controlled below 0.4V, so that the conduction loss can be reduced, and the conversion efficiency of the AC-DC is improved.

It should be noted that the foregoing detailed description is exemplary and is intended to provide further explanation of the utility model. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is intended to include the plural unless the context clearly indicates otherwise. Furthermore, it will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, steps, operations, devices, components, and/or groups thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or otherwise described herein.

Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those elements but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways, such as rotated 90 degrees or at other orientations, and the spatially relative descriptors used herein interpreted accordingly.

In the above detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, like numerals typically identify like components unless context indicates otherwise. The illustrated embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein.

The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (8)

1. A composite structure for use as an AC-DC power switch, the composite structure comprising:

an N+ type semiconductor substrate (1);

an N-type epitaxial layer (2) disposed over the N+ type semiconductor substrate (1);

a P-type doped region (3) arranged in the N-type epitaxial layer (2);

the first N+ type doped region (4) and the second N+ type doped region (5) are respectively arranged in the P type doped region (3);

the P++ type doped region (6) is arranged in the first N+ type doped region (4) and is used as an emitting region of the first triode;

a plurality of metal electrodes arranged above the P-type doped region (3), the first N+ type doped region (4), the second N+ type doped region (5) and the P++ type doped region (6);

a dielectric layer (7) is arranged among the plurality of metal electrodes;

and a collector (12) of a second triode arranged on the back surface of the N+ type semiconductor substrate (1).

2. The composite structure for use as an AC-DC power switch according to claim 1, wherein the plurality of metal electrodes comprises a common electrode (8), a base electrode (9) of the first transistor, an emitter electrode (10) of the first transistor and an emitter electrode (11) of the second transistor, the common electrode (8) being disposed above the P-type doped region (3), the base electrode (9) of the first transistor being disposed above the first n+ -type doped region (4), the emitter electrode (10) of the first transistor being disposed above the p++ -type doped region (6), the emitter electrode (11) of the second transistor being disposed above the second n+ -type doped region (5).

3. Composite structure for use as an AC-DC power switch according to claim 1, characterized in that the P-doped region (3) acts as collector region for the first transistor and base region for the second transistor.

4. Composite structure for use as an AC-DC power switch according to claim 1, characterized in that the first n+ -doped region (4) acts as a base region of the first transistor and the second n+ -doped region (5) acts as an emitter region of the second transistor.

5. Composite structure for use as an AC-DC power switch according to claim 2, characterized in that the common electrode (8) is the collector of the first transistor and the base of the second transistor.

6. The composite structure for use as an AC-DC power switch of claim 1, wherein said first transistor is a PNP transistor.

7. The composite structure for use as an AC-DC power switch according to claim 1, wherein the second transistor is an NPN transistor.

8. A circuit for use as a composite structure for an AC-DC power switch, comprising a composite structure for an AC-DC power switch according to any of claims 1-7, the circuit comprising:

PNP and NPN transistors;

and the collector electrode of the PNP triode is electrically connected with the base electrode of the NPN triode.