WO2020253433A1

WO2020253433A1 - Power source switching circuit and power source apparatus

Info

Publication number: WO2020253433A1
Application number: PCT/CN2020/090761
Authority: WO
Inventors: 黄国生
Original assignee: 深圳光峰科技股份有限公司
Priority date: 2019-06-19
Filing date: 2020-05-18
Publication date: 2020-12-24
Also published as: CN209881490U

Abstract

A power source switching circuit, applied to a power source apparatus. The power source apparatus comprises a first power source and a second power source, wherein the first power source is used for supplying power to a system; the second power source is a backup power source; the first power source and the second power source are used for supplying different voltage values, and the voltage value of the first power source is greater than the voltage value of the second power source; the power source switching circuit is electrically connected to the first power source and the second power source; when the first power source works normally, the power source switching circuit outputs a first voltage; and when the first power source is abnormal, the power source switching circuit outputs a second voltage, wherein the voltage value of the first voltage is less than the voltage value of the second voltage. Further provided is a power source apparatus comprising the power source switching circuit.

Description

Power switching circuit and power supply device

Technical field

The utility model relates to a power switching circuit, in particular to a power switching circuit used for seamless switching among multiple power sources.

Background technique

When designing a power supply device, the continuity of use and product volume are important considerations. For example, in the design of the power supply device of a cinema machine, multiple power modules with different output voltages are included. In order to reduce the situation that the lights are turned off during the show, or the movie is stopped due to the failure of the power module of a specific output voltage, it is necessary to add backup to the key power supply module Features. However, in a power supply device with a limited size, it is difficult to additionally provide a separate backup power supply module, and a power supply module with another output voltage needs to be used as a backup power supply in the original power supply device.

Utility model content

In view of this, it is necessary to provide a power switching circuit with a simple structure and a lower cost.

A power supply switching circuit is applied to a power supply device. The power supply device includes a first power supply and a second power supply. The first power supply is used to supply power to the system, the second power supply is a backup power supply, and the first power supply And the second power supply are used to provide different voltage values, and the voltage value of the first power supply is greater than the voltage value of the second power supply, and the power switching circuit is electrically connected to the first power supply and the second voltage When the first power supply is working normally, the power supply switching circuit outputs a first voltage; when the first power supply is abnormal, the power supply switching circuit outputs a second voltage, wherein the voltage value of the first voltage A voltage value smaller than the second voltage.

Preferably, the power switching circuit includes a first voltage dividing module, a second voltage dividing module, a switch module, and a voltage output module. One end of the first voltage dividing module is electrically connected to the first power source, and the first voltage dividing module is electrically connected to the first power source. One end of the two voltage divider module is electrically connected to the second power source, the other end is electrically connected to the other end of the first voltage divider module, and one end of the switch module is electrically connected to the first voltage divider module. The other end of the switch module is electrically connected to the second voltage dividing module, and the voltage output module is electrically connected to the second voltage dividing module for outputting the first voltage or the second voltage.

Preferably, the first voltage dividing module includes a first voltage dividing element and a second voltage dividing element, the second voltage dividing module includes a third voltage dividing element and a fourth voltage dividing element, the first voltage dividing element One end is electrically connected to the first power source, the other end is electrically connected to one end of the second voltage dividing element, one end of the third voltage dividing element is electrically connected to the second power source, and the other end is electrically connected to One end of the fourth voltage dividing element, the other end of the fourth voltage dividing element is electrically connected to the other end of the second voltage dividing element, and one end of the switch module is electrically connected to the first voltage dividing element And the second voltage dividing element, the other end of the switch module is electrically connected between the third voltage dividing element and the fourth voltage dividing element, the voltage output module includes a first diode The first diode includes a first end, a second end, and a third end, and the first end of the first diode serves as the output end of the power switching circuit to output the first voltage or For the second voltage, the second end of the first diode is electrically connected between the third voltage dividing element and the fourth voltage dividing element, and the third end of the first diode Is electrically connected to the other end of the fourth voltage dividing element, the first diode is a controllable precision voltage regulator source, the first end of the first diode is the cathode, and the second end is the reference electrode, The third end is the anode.

Preferably, the switch module includes a first resistor and a first switch tube, the first switch tube includes a first terminal, a second terminal, and a third terminal, and the first terminal of the first switch tube is electrically connected to Between the first voltage dividing element and the second voltage dividing element, the second end of the first switch tube is electrically connected to one end of the first resistor, and the third end of the first switch tube Electrically connected to the other end of the second voltage dividing element; the other end of the first resistor is electrically connected between the third voltage dividing element and the fourth voltage dividing element; the first switch The tube is a triode, the first end of the first switch tube is the base, the second end is the emitter, and the third end is the collector.

Preferably, the switch module includes a second switch tube, a third switch tube, a second resistor, and a third resistor; the first end of the second switch tube is electrically connected to the first voltage dividing element and the Between the second voltage divider elements, the second end of the second switch tube is electrically connected to one end of the second resistor, and the other end of the second resistor is electrically connected to the second power source. The third end of the second switch tube is electrically connected to the other end of the second voltage dividing element; the first end of the third switch tube is electrically connected to the second end of the second switch tube and the first end Between the two resistors, the second end of the third switch tube is electrically connected to one end of the third resistor, and the other end of the third resistor is electrically connected to the third voltage dividing element and the fourth resistor. Between the voltage dividing elements, the third end of the third switching tube is electrically connected to the other end of the second voltage dividing element; the second switching tube and the third switching tube are both field effect transistors, The first terminal is a gate, the second terminal is a drain, and the third terminal is a source.

Preferably, the switch module includes a fourth switch tube, a fifth switch tube, a fourth resistor, and a fifth resistor, and the first end of the fourth switch tube is electrically connected to the first voltage dividing element and the Between the second voltage dividing elements, the second end of the fourth switch tube is electrically connected to one end of the fourth resistor, and the third end of the fourth switch tube is electrically connected to the second voltage divider The other end of the element; the first end of the fifth switch tube is electrically connected to the other end of the fourth resistor, and the second end of the fifth switch tube is electrically connected to the fifth resistor through the The second power supply, the third end of the fifth switch tube is electrically connected between the third voltage dividing element and the fourth voltage dividing element; the fourth switch tube is an NPN type triode, and the first The first end of the four switch tube is the base, the second end is the collector, and the third end is the emitter; the fifth switch is a PNP type transistor, and the first end of the fifth switch is the base, The second end is the emitter, and the third end is the collector.

Preferably, the first voltage dividing module includes a first voltage dividing element and a second voltage dividing element, the second voltage dividing module includes a third voltage dividing element and a fourth voltage dividing element, the first voltage dividing element One end is electrically connected to the first power source, the other end is electrically connected to one end of the second voltage dividing element and one end of the switch module, and one end of the third voltage dividing element is electrically connected to the second Power supply, the voltage output module includes a photocoupler and a second diode, the first end of the photocoupler is electrically connected to the other end of the third voltage divider through the second diode, so The second end of the photocoupler is electrically connected to the other end of the switch module and one end of the fourth voltage dividing element, and the other end of the fourth voltage dividing element is electrically connected to the second voltage dividing element On the other end.

Preferably, the first voltage dividing element, the second voltage dividing element and the third voltage dividing element are all resistors, the fourth voltage dividing element is a resistor or a diode, and the second diode is A voltage regulator tube, the switch module includes a sixth switch tube, a first end of the sixth switch tube is electrically connected between the first voltage dividing element and the second voltage dividing element, the sixth switch The second end of the tube is electrically connected to the second end of the photocoupler, the third end of the sixth switch tube is electrically connected to the other end of the second voltage divider, and the sixth switch tube is NPN The first end is a base electrode, the second end is a collector, and the third end is an emitter.

A power supply device includes the above-mentioned power supply switching circuit.

Preferably, the power supply device further includes a second constant current conversion module, a third constant current conversion module, a second laser constant current drive module, and an output terminal. The second constant current conversion module and the third constant current conversion module are respectively Is electrically connected to the output terminal, the third constant current conversion module is also electrically connected to the second laser constant current drive module, the power switch circuit is provided in the third constant current conversion module, and The first power source is provided in the second constant current conversion module, the second power source is provided in the third constant current conversion module, and when the first power source is working normally, the second constant current conversion module outputs The first output voltage is to the output terminal, the third constant current conversion module outputs a second output voltage to the second laser constant current drive module; when the first power supply is abnormal, the third constant current conversion module The module outputs a third output voltage to the output terminal and the second laser constant current drive module, the voltage value of the first output voltage is equal to the voltage value of the third output voltage, and the voltage value of the first output voltage The value is greater than the voltage value of the second output voltage.

The power supply device sets the second constant current conversion module as the main power supply, and outputs 12 volts to the output terminal during normal operation; the power supply device also sets a third constant current conversion module with a power switching circuit as a backup Power supply. The third constant current conversion module can output a voltage of 10 volts to the second laser constant current drive module when the second constant current conversion module is working normally. When the second constant current conversion module is abnormal, the third constant current conversion module is switched to output a 12 volt voltage to the output terminal through the power switching circuit to seamlessly switch the backup power supply, thereby ensuring the output The system is powered at the end without affecting its normal performance. That is to say, it not only satisfies the backup function, ensures the normal power supply of the system, and can still supply power to its load.

Description of the drawings

Fig. 1 is a functional module diagram of a preferred embodiment of the power supply device of the present invention.

Fig. 2 is a schematic circuit diagram of the first embodiment of the power switching circuit of the present invention.

FIG. 3 is a schematic circuit diagram of the second embodiment of the power switching circuit of the present invention.

4 is a schematic circuit diagram of the third embodiment of the power switching circuit of the present invention.

Fig. 5 is a schematic circuit diagram of a fourth embodiment of the power switching circuit of the present invention.

6 is a schematic circuit diagram of the fifth embodiment of the power switching circuit of the present invention.

Symbol description of main components

Power supply device 1

Power supply module 10

The first constant current conversion module 22

The second constant current conversion module 24

The third constant current conversion module 26

Fourth Constant Current Conversion Module 28

Power switching circuit

30, 50, 60, 70, 80

The first laser constant current drive module 42

The second laser constant current drive module 44

The third laser constant current drive module 46

Output end 48

The first

voltage divider component

31, 51

Second voltage divider component 32

The third voltage divider component 33

The fourth

voltage divider component

34, 81

Switch

module

35, 55, 65, 75

The first switch tube Q1

The first diode D1

The first resistance R1

The second resistance R2

The third resistance R3

The fourth resistor R4

Fifth resistor R5

Power supply 12V1, 10V

The second switch tube Q2

The third switch tube Q3

The fourth switch tube Q4

Fifth switch tube Q5

The sixth switch tube Q6

Second diode D2

Optocoupler P1

The following specific embodiments will further illustrate the present invention in conjunction with the above drawings.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, not all implementations. example. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present utility model.

It should be noted that when an element is referred to as being "electrically connected" to another element, it can be directly on the other element or a central element may also exist. When an element is considered to be "electrically connected" to another element, it can be a contact connection, for example, it can be a wire connection or a non-contact connection, for example, it can be a non-contact coupling.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the technical field of the utility model. The terms used in the description of the utility model herein are only for the purpose of describing specific embodiments, and are not intended to limit the utility model. The term "and/or" as used herein includes any and all combinations of one or more related listed items.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

Please refer to FIG. 1, the first preferred embodiment of the present invention provides a power supply device 1 for providing multiple types of output voltages. The power supply device 1 can be applied to projectors, such as cinema projectors, projectors, engineering machines, etc., to provide power. The power supply device 1 includes a power supply module 10, a first constant current conversion module 22, a second constant current conversion module 24, a third constant current conversion module 26, a fourth constant current conversion module 28, a power supply switching circuit 30, and a first laser The constant current driving module 42, the second laser constant current driving module 44, the third laser constant current driving module 46 and the output terminal 48. Wherein, the power switching circuit 30 is provided in the third constant current conversion module 26. In other embodiments, the power switching circuit 30 may also be provided in other constant current conversion modules.

The power supply module 10 is electrically connected to the first constant current conversion module 22, the second constant current conversion module 24, the third constant current conversion module 26, and the fourth constant current conversion module 28 to provide voltage to these modules. In this embodiment, the power supply module 10 provides 390 volt alternating current.

In this embodiment, the first constant current conversion module 22, the second constant current conversion module 24, the third constant current conversion module 26, and the fourth constant current conversion module 28 are AC-DC power supply modules for connecting the The alternating current provided by the power supply module 10 is converted into a constant direct current, and constant direct currents of different voltages are provided respectively. The first constant current conversion module 22 converts the alternating current provided by the power supply module 10 into constant direct current and outputs a voltage of 24 volts; the second constant current conversion module 24 converts the alternating current provided by the power supply module 10 into constant DC power and output a voltage of 12 volts; the third constant current conversion module 26 converts the AC power provided by the power supply module 10 into a constant DC power and output a voltage of 10 volts or 12 volts; the fourth constant current conversion module 28 converts The AC power provided by the power supply module 10 is converted into a constant DC power and outputs a voltage of 24 volts.

The first constant current conversion module 22 is electrically connected to the first laser constant current driving module 42 and supplies power to the first laser constant current driving module 42. In this embodiment, the first constant current conversion module 22 provides the first laser constant current driving module 42 with a voltage of 24 volts. The fourth constant current conversion module 28 is electrically connected to the third laser constant current driving module 46 and supplies power to the third laser constant current driving module 46. In this embodiment, the fourth constant current conversion module 28 provides the third laser constant current driving module 46 with a voltage of 24 volts.

The second constant current conversion module 24 is electrically connected to the output terminal 48 to serve as the system power supply of the power supply device 1. The third constant current conversion module 26 is electrically connected to the second laser constant current driving module 44 and the output terminal 48 respectively. The output terminal 48 can be connected to a load, and the power supply device 1 outputs a constant voltage through the output terminal 48 to supply power to the system. In this embodiment, the second constant current conversion module 24 is used as the main power supply, and the third constant current conversion module 26 is used as the backup power supply. The second constant current conversion module 24 outputs a voltage of 12 volts to the output terminal 48. The third constant current conversion module 26 provides a voltage of 10 volts to the second laser constant current drive module 44 to meet the requirements of different voltage drops under light and heavy loads. In this embodiment, the second laser constant current driving module 44 is a lamp load. The lamp load is driven by a constant current, and when the load is light, the voltage drop of the lamp is relatively low, about 13 volts. At medium load, the voltage drop of the lamp is about 15 volts. When heavily loaded, the voltage drop of the lamp is about 18 volts. The third constant current conversion module 26 can also output a voltage of 12 volts to the output terminal 48, that is, supply power for the system.

Please refer to FIG. 2, the power switching circuit 30 of the first embodiment of the present invention includes a first voltage dividing module, a second voltage dividing module, a switch module 35 and a voltage output module. In this embodiment, the first voltage dividing module includes a first voltage dividing element 31 and a second voltage dividing element 32. The second voltage divider module includes a third voltage divider 33 and a fourth voltage divider 34. The first voltage dividing element 31, the second voltage dividing element 32, the third voltage dividing element 33, and the fourth voltage dividing element 34 are all resistors. The voltage output module includes a first diode D1.

One end of the first voltage dividing element 31 is electrically connected to the second constant current conversion module 24, that is, to a 12 volt constant voltage power supply 12V1, and the other end of the first voltage dividing element 31 is electrically connected Connected to one end of the second voltage dividing element 32. One end of the third voltage divider 33 is electrically connected to the 10V constant voltage power supply 10V of the third constant current conversion module 26. The other end of the third voltage dividing element 33 is electrically connected to one end of the fourth voltage dividing element 34. The other end of the fourth voltage dividing element 34 is electrically connected to the other end of the second voltage dividing element 32.

In this embodiment, the switch module 35 includes a first switch tube Q1 and a first resistor R1. The first switch tube Q1 includes a first end, a second end and a third end. The first end of the first switch tube Q1 is electrically connected between the first voltage dividing element 31 and the second voltage dividing element 32. The second end of the first switch tube Q1 is electrically connected to one end of the first resistor R1. The third end of the first switch tube Q1 is electrically connected to the other end of the second voltage divider 32. In this embodiment, the first switching tube Q1 is a PNP transistor, the first end is a base, the second end is an emitter, and the third end is a collector. The other end of the first resistor R1 is electrically connected to the 10V constant voltage power supply 10V of the third constant current conversion module 26 through the third voltage dividing element 33. The first diode D1 includes a first end, a second end, and a third end. The first terminal of the first diode D1 serves as the output terminal of the third constant current conversion module 26. The second end of the first diode D1 is electrically connected between the third voltage dividing element 33 and the fourth voltage dividing element 34. The third end of the first diode D1 is electrically connected to the other end of the fourth voltage dividing element 34.

In this embodiment, the first diode D1 is a controllable precision voltage stabilizing source, the first end is the cathode, the second end is the reference electrode, and the third end is the anode. The controllable precision voltage stabilization source has a precision reference voltage source inside, and the resistors connected to the second end and the third end enable the first end of the controllable precision voltage stabilization source to have a continuously adjustable output voltage stabilization value, and the output current is relatively large. Played a better role of regulated power supply.

When the second constant current conversion module 24 works normally, it outputs a voltage of 12 volts to the output terminal 48 as a system power supply output. At this time, the first switching tube Q1 is working in an off state, and the output voltage of the first terminal of the first diode D1 is divided by the third voltage dividing element 33 and the fourth voltage dividing element 34. , So that the first terminal of the first diode D1 outputs a voltage of about 10 volts. Therefore, the first terminal of the first diode D1 outputs a voltage of 10 volts to the second laser constant current driving module 44 to meet the requirements of different voltage drops under light and heavy loads.

When the second constant current conversion module 24 is abnormal, the base of the first switch tube Q1 detects the voltage drop of the second constant current conversion module 24, and the first switch tube Q1 is turned on. . At this time, the output voltage of the first terminal of the first diode D1 is divided by the third voltage dividing element 33, the fourth voltage dividing element 34 and the first resistor R1. Wherein, the fourth voltage dividing element 34 and the first resistor R1 are connected in parallel, so that the voltages connected to the second terminal and the third terminal of the first diode D1 change, so that the voltage of the first diode D1 The voltage output from the first terminal rises from 10 volts to 12 volts. Therefore, the first terminal of the first diode D1 outputs a voltage of 12 volts to the output terminal 48, and the voltage of 12 volts is continuously used as the system power supply output. At the same time, the first terminal of the first diode D1 outputs a voltage of 12 volts to the second laser constant current driving module 44. At this time, the 12V voltage output from the first terminal of the first diode D1 can normally drive the medium load (15V) and heavy load (18V) operation. When the 12 volt voltage drives a light load (13 volts), the light load can also work, but the ripple is not so stable, which may cause slight flicker. In other words, when the 12 volt power supply for the system fails (that is, the second constant current conversion module 24 is abnormal), the power switching circuit 30 can seamlessly switch and output the 12 volt voltage, which not only meets the backup function, but also Does not affect the normal performance of its load. Please refer to FIG. 3, which is a power switching circuit 50 provided by the second embodiment of the present invention. The power switching circuit 50 includes a first voltage dividing element 51, a second voltage dividing element 32, a third voltage dividing element 33, a fourth voltage dividing element 34, a switch module 55 and a first diode D1.

In this embodiment, the structure of the power switching circuit 50 is similar to the structure of the power switching circuit 30 in the first embodiment, except that the first voltage divider 51 is a diode. In addition, the specific circuit structure of the switch module 55 is also different from that of the switch module 35 in the first embodiment.

Specifically, in this embodiment, the switch module 55 includes a second switch tube Q2, a third switch tube Q3, a second resistor R2, and a third resistor R3. The second switch tube Q2 includes a first end, a second end, and a third end. The first end of the second switch tube Q2 is electrically connected between the first voltage dividing element 51 and the second voltage dividing element 32. The second end of the second switch tube Q2 is electrically connected to one end of the second resistor R2. The third end of the second switch tube Q2 is electrically connected to the other end of the second voltage divider 32. The other end of the second resistor R2 is electrically connected to the 10V constant voltage power supply 10V of the third constant current conversion module 26.

The third switch tube Q3 includes a first end, a second end, and a third end. The first terminal of the third switch tube Q3 is electrically connected between the second terminal of the second switch tube Q2 and the second resistor R2. The second end of the third switch tube Q3 is electrically connected to one end of the third resistor R3. The third end of the third switch tube Q3 is electrically connected to the other end of the second voltage divider 32. The other end of the third resistor R3 is electrically connected between the third voltage dividing element 33 and the fourth voltage dividing element 34.

In this embodiment, the second switch transistor Q2 and the third switch transistor Q3 are both field effect transistors, the first terminal is a gate, the second terminal is a drain, and the third terminal is Source.

When the second constant current conversion module 24 works normally, it outputs a voltage of 12 volts to the output terminal 48 as a system power supply output. At this time, the second switching tube Q2 is turned on, the third switching tube Q3 is turned off, and the output voltage of the first terminal of the first diode D1 passes through the third voltage divider 33 and the fourth divider. The voltage dividing element 34 is set so that the first terminal of the first diode D1 outputs a voltage of about 10 volts. Therefore, the first end of the first diode D1 outputs a voltage of 10 volts to the second laser constant current drive module 44 to meet the requirements of different voltage drops under light and heavy loads.

When the second constant current conversion module 24 is abnormal, the voltage of the first terminal of the second switching tube Q2 drops, so that the second switching tube Q2 is turned off, and the first terminal of the third switching tube Q3 is The voltage rises, the third switch tube Q3 is turned on, and the current flowing through the third resistor R3 rises, so that the third resistor R3 is connected in parallel with the fourth voltage dividing element 34. At this time, the output voltage of the first terminal of the first diode D1 is divided by the third voltage dividing element 33, the fourth voltage dividing element 34, and the third resistor R3. Wherein, the fourth voltage dividing element 34 and the third resistor R3 are connected in parallel, so that the voltage connected to the second terminal and the third terminal of the first diode D1 changes, so that the The voltage output from the first terminal rises from 10 volts to 12 volts. Therefore, the first terminal of the first diode D1 outputs a voltage of 12 volts to the output terminal 48 to continuously use a voltage of 12 volts as the system power supply output. At the same time, the first terminal of the first diode D1 outputs a voltage of 12 volts to the second laser constant current driving module 44.

Please refer to FIG. 4, which is a power switching circuit 60 provided by the third embodiment of the present invention. The power switching circuit 60 includes a first voltage dividing element 31, a second voltage dividing element 32, a third voltage dividing element 33, a fourth voltage dividing element 34, a switch module 65 and a first diode D1.

In this embodiment, the structure of the power switch circuit 60 is similar to the structure of the power switch circuit 30 in the first embodiment, except that the specific circuit structure of the switch module 65 is also the same as that of the switch module 35 in the first embodiment. different.

Specifically, in this embodiment, the switch module 65 includes a fourth switch tube Q4, a fifth switch tube Q5, a fourth resistor R4, and a fifth resistor R5. The fourth switch tube Q4 includes a first end, a second end, and a third end. The first end of the fourth switch tube Q4 is electrically connected between the first voltage dividing element 31 and the second voltage dividing element 32. The second end of the fourth switch tube Q4 is electrically connected to one end of the fourth resistor R4. The third end of the fourth switch tube Q4 is electrically connected to the other end of the second voltage divider 32. The fifth switch tube Q5 includes a first end, a second end, and a third end. The first end of the fifth switch tube Q5 is electrically connected to the other end of the fourth resistor R4. The second end of the fifth switch tube Q5 is electrically connected to the 10V constant voltage power supply 10V of the third constant current conversion module 26 through the fifth resistor R5. The third terminal of the fifth switch tube Q5 is electrically connected between the third voltage dividing element 33 and the fourth voltage dividing element 34.

In this embodiment, the fourth switching tube Q4 is an NPN transistor. The first end of the fourth switch tube Q4 is the base, the second end is the collector, and the third end is the emitter. The fifth switch tube Q5 is a PNP type transistor. The first end of the fifth switch tube Q5 is the base, the second end is the emitter, and the third end is the collector. When the second constant current conversion module 24 works normally, it outputs a voltage of 12 volts to the output terminal 48 as a system power supply output. At this time, the fifth switch tube Q5 is saturated and turned on, the fifth resistor R5 is close to short-circuit with the third voltage divider 33, and the output voltage of the first terminal of the first diode D1 passes through the The third voltage dividing element 33, the fourth voltage dividing element 34 and the fifth resistor R5 are divided into voltage settings so that the output voltage of the first end of the first diode D1 is about 10 volts. Therefore, the first terminal of the first diode D1 outputs a voltage of 10 volts to the second laser constant current driving module 44 to meet the requirements of different voltage drops under light and heavy loads.

When the second constant current conversion module 24 is abnormal, the voltage at the first terminal and the third terminal of the fourth switch tube Q4 drops, the current flowing through the fourth resistor R4 becomes smaller, and the fifth switch The transistor Q5 is turned off, disconnecting the fifth resistor R5 and the third voltage dividing element 33, and the output voltage of the first end of the first diode D1 passes through the third voltage dividing element 33 and the fourth voltage dividing element 33. The voltage division setting of the voltage element makes the voltage connected to the second terminal and the third terminal of the first diode D1 change, so that the voltage output by the first terminal of the first diode D1 rises from 10 volts To 12 volts. Therefore, the first terminal of the first diode D1 outputs a voltage of 12 volts to the output terminal 48 to continuously use a voltage of 12 volts as the system power supply output. At the same time, the first terminal of the first diode D1 outputs a voltage of 12 volts to the second laser constant current driving module 44.

Please refer to FIG. 5, which is a power switching circuit 70 provided by the fourth embodiment of the present invention. The power switching circuit 70 includes a first voltage dividing module, a second voltage dividing module, a switch module, and a voltage output module. The first voltage dividing module includes a first voltage dividing element 31 and a second voltage dividing element 32. The second voltage divider module includes a third voltage divider 33 and a fourth voltage divider 34. The voltage output module includes a photocoupler P1 and a second diode D2.

In this embodiment, the first voltage dividing element 31, the second voltage dividing element 32, the third voltage dividing element 33, and the fourth voltage dividing element 34 are all resistors. The second diode D2 is a voltage regulator tube.

One end of the first voltage divider 31 is electrically connected to the second constant current conversion module 24, that is, it is electrically connected to a 12V constant voltage power supply 12V1. The other end of the first voltage dividing element 31 is electrically connected to one end of the second voltage dividing element 32. One end of the third voltage dividing element 33 is electrically connected to the 10V constant voltage power supply 10V of the third constant current conversion module 26. The other end of the third voltage dividing element 33 is electrically connected to the first end of the photocoupler P1 through the second diode D2. The second end of the photocoupler P1 is electrically connected to one end of the fourth voltage dividing element 34. The other end of the fourth voltage dividing element 34 is electrically connected to the other end of the second voltage dividing element 32.

In this embodiment, the switch module 75 includes a sixth switch tube Q6. The sixth switch tube Q6 includes a first end, a second end, and a third end. The first end of the sixth switch tube Q6 is electrically connected between the first voltage dividing element 31 and the second voltage dividing element 32. The second end of the sixth switch tube Q6 is electrically connected between the second end of the photocoupler P1 and the fourth voltage dividing element 34. The third end of the sixth switch tube Q6 is electrically connected to the other end of the second voltage divider 32.

In this embodiment, the sixth switch tube Q6 is an NPN transistor. The first end of the sixth switch tube Q6 is the base, the second end is the collector, and the third end is the emitter.

When the second constant current conversion module 24 works normally, it outputs a voltage of 12 volts to the output terminal 48 as a system power supply output. At this time, the sixth switch tube Q6 is turned on, and the output terminal voltage of the third constant current conversion module 26 is the voltage drop of the second diode D2 and the forward voltage drop of the photocoupler P1.

When the second constant current conversion module 24 is abnormal, the sixth switch Q6 is turned off. At this time, the output terminal voltage of the third constant current conversion module 26 is the voltage drop of the second diode D2, the forward voltage drop of the photocoupler P1, and the voltage drop of the fourth voltage divider 34 Pressure drop. Thus, the output terminal voltage of the third constant current conversion module 26 is increased to continuously supply power to the system.

Please refer to FIG. 6, which is a power switching circuit 80 provided by the fifth embodiment of the present invention. The power switching circuit 80 includes a first voltage dividing element 31, a second voltage dividing element 32, a third voltage dividing element 33, a fourth voltage dividing element 81, a switch module 75, a photocoupler P1 and a second diode D2 .

In this embodiment, the power switching circuit 80 has substantially the same structure as the power switching circuit 70 of the fourth embodiment, except that the fourth switching element 81 in the power switching circuit 80 of the fifth embodiment is a diode. Instead of resistance. The working principle of the power switching circuit 80 is substantially the same as the working principle of the power switching circuit 70, and will not be repeated here.

The power supply device 1 is provided with the second constant current conversion module 24 as the main power supply, and outputs 12 volts to the output terminal 48 during normal operation; the power supply device 1 is also provided with a third constant current switching circuit 30 The stream conversion module 26 serves as a backup power supply. The third constant current conversion module 26 can output a voltage of 10 volts to the second laser constant current driving module 44 when the second constant current conversion module 24 is working normally. When the second constant current conversion module 24 is abnormal, the third constant current conversion module 26 is switched by the power switching circuit 30 to output a 12 volt voltage to the output terminal 48 to seamlessly switch the backup power supply. The system power supply of the output terminal 48 is guaranteed without affecting its normal performance. That is to say, it not only satisfies the backup function, ensures the normal power supply of the system, and can still supply power to its load.

The above embodiments are only used to illustrate the technical solutions of the present utility model and not to limit it. Although the present utility model is described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that the technical solution of the present utility model can be modified Or equivalent replacements should not depart from the spirit and scope of the technical solution of the present invention. Those skilled in the art can also make other changes within the spirit of the utility model and other changes used in the design of the utility model, as long as they do not deviate from the technical effect of the utility model. These changes made in accordance with the spirit of the utility model should all be included in the scope of protection claimed by the utility model.

Claims

A power supply switching circuit is applied to a power supply device. The power supply device includes a first power supply and a second power supply. The first power supply is used to supply power to the system, the second power supply is a backup power supply, and the first power supply And the second power supply are used to provide different voltage values, and the voltage value of the first power supply is greater than the voltage value of the second power supply, characterized in that: the power switching circuit is electrically connected to the first power supply and all For the second power supply, when the first power supply is working normally, the power supply switching circuit outputs a first voltage; when the first power supply is abnormal, the power supply switching circuit outputs a second voltage, wherein the first voltage The voltage value of is less than the voltage value of the second voltage.
The power switching circuit according to claim 1, wherein the power switching circuit comprises a first voltage dividing module, a second voltage dividing module, a switch module, and a voltage output module, and one end of the first voltage dividing module is electrically Is electrically connected to the first power source, one end of the second voltage dividing module is electrically connected to the second power source, the other end is electrically connected to the other end of the first voltage dividing module, and one end of the switch module is electrically connected Connected to the first voltage dividing module, the other end of the switch module is electrically connected to the second voltage dividing module, and the voltage output module is electrically connected to the second voltage dividing module for outputting the first A voltage or the second voltage.
The power switching circuit of claim 2, wherein the first voltage dividing module includes a first voltage dividing element and a second voltage dividing element, and the second voltage dividing module includes a third voltage dividing element and a second voltage dividing element. A four-voltage dividing element, one end of the first voltage dividing element is electrically connected to the first power source, the other end is electrically connected to one end of the second voltage dividing element, and one end of the third voltage dividing element is electrically connected To the second power source, the other end is electrically connected to one end of the fourth voltage dividing element, the other end of the fourth voltage dividing element is electrically connected to the other end of the second voltage dividing element, the switch module One end of the switch module is electrically connected between the first voltage dividing element and the second voltage dividing element, and the other end of the switch module is electrically connected between the third voltage dividing element and the fourth voltage dividing element , The voltage output module includes a first diode, the first diode includes a first end, a second end, and a third end, and the first end of the first diode serves as the power switching circuit To output the first voltage or the second voltage, and the second end of the first diode is electrically connected between the third voltage dividing element and the fourth voltage dividing element , The third end of the first diode is electrically connected to the other end of the fourth voltage dividing element, the first diode is a controllable precision voltage regulator source, and the first diode is One end is the cathode, the second end is the reference electrode, and the third end is the anode.
7. The power switching circuit of claim 3, wherein the switch module includes a first resistor and a first switch tube, the first switch tube includes a first end, a second end, and a third end, and The first end of the first switch tube is electrically connected between the first voltage dividing element and the second voltage dividing element, and the second end of the first switch tube is electrically connected to the first resistor One end, the third end of the first switch tube is electrically connected to the other end of the second voltage dividing element; the other end of the first resistor is electrically connected to the third voltage dividing element and the first Between four voltage divider elements; the first switch tube is a triode, the first end of the first switch tube is the base, the second end is the emitter, and the third end is the collector.
4. The power switching circuit of claim 3, wherein the switch module includes a second switch tube, a third switch tube, a second resistor, and a third resistor; the first terminal of the second switch tube is electrically Connected between the first voltage dividing element and the second voltage dividing element, the second end of the second switch tube is electrically connected to one end of the second resistor, and the other end of the second resistor Is electrically connected to the second power source, the third end of the second switch tube is electrically connected to the other end of the second voltage dividing element; the first end of the third switch tube is electrically connected to the Between the second end of the second switch tube and the second resistor, the second end of the third switch tube is electrically connected to one end of the third resistor, and the other end of the third resistor is electrically connected to Between the third voltage dividing element and the fourth voltage dividing element, the third end of the third switch tube is electrically connected to the other end of the second voltage dividing element; the second switch tube and The third switching tube is a field effect tube, the first terminal is a gate, the second terminal is a drain, and the third terminal is a source.
The power switching circuit of claim 3, wherein the switch module includes a fourth switch tube, a fifth switch tube, a fourth resistor, and a fifth resistor, and the first terminal of the fourth switch tube is electrically conductive Is connected between the first voltage dividing element and the second voltage dividing element, the second end of the fourth switch tube is electrically connected to one end of the fourth resistor, and the second end of the fourth switch tube The three ends are electrically connected to the other end of the second voltage divider element; the first end of the fifth switch tube is electrically connected to the other end of the fourth resistor, and the second end of the fifth switch tube The fifth resistor is electrically connected to the second power source, and the third end of the fifth switch tube is electrically connected between the third voltage dividing element and the fourth voltage dividing element; The fourth switch tube is an NPN type transistor, the first end of the fourth switch tube is a base, the second end is a collector, and the third end is an emitter; the fifth switch tube is a PNP type triode, the The first end of the fifth switch tube is the base, the second end is the emitter, and the third end is the collector.
The power switching circuit of claim 2, wherein the first voltage dividing module includes a first voltage dividing element and a second voltage dividing element, and the second voltage dividing module includes a third voltage dividing element and a second voltage dividing element. A four-voltage dividing element, one end of the first voltage dividing element is electrically connected to the first power source, and the other end is electrically connected to one end of the second voltage dividing element and one end of the switch module, the third One end of the voltage dividing element is electrically connected to the second power source, the voltage output module includes a photocoupler and a second diode, and the first end of the photocoupler is electrically connected to the second power source through the second diode. The other end of the third voltage dividing element, the second end of the photocoupler are electrically connected to the other end of the switch module and one end of the fourth voltage dividing element. The other end is electrically connected to the other end of the second voltage dividing element.
The power switching circuit of claim 7, wherein the first voltage dividing element, the second voltage dividing element, and the third voltage dividing element are all resistors, and the fourth voltage dividing element is A resistor or a diode, the second diode is a zener tube, the switch module includes a sixth switch tube, the first end of the sixth switch tube is electrically connected to the first voltage dividing element and the first Between the two voltage dividing elements, the second end of the sixth switch tube is electrically connected to the second end of the photocoupler, and the third end of the sixth switch tube is electrically connected to the second voltage dividing element On the other end of the switch tube, the sixth switch tube is an NPN transistor, the first end is a base, the second end is a collector, and the third end is an emitter.
A power supply device, characterized in that: the power supply device includes the power switching circuit according to any one of claims 1-8.
9. The power supply device of claim 9, wherein the power supply device further comprises a second constant current conversion module, a third constant current conversion module, a second laser constant current drive module and an output terminal, the second constant current conversion module The current conversion module and the third constant current conversion module are both electrically connected to the output end, the third constant current conversion module is also electrically connected to the second laser constant current drive module, and the power switch circuit is arranged at In the third constant current conversion module, the first power source is set in the second constant current conversion module, and the second power source is set in the third constant current conversion module. When the first power source works normally When the second constant current conversion module outputs a first output voltage to the output terminal, the third constant current conversion module outputs a second output voltage to the second laser constant current drive module; when the first When the power supply is abnormal, the third constant current conversion module outputs a third output voltage to the output terminal and the second laser constant current drive module, and the voltage value of the first output voltage is equal to that of the third output voltage The voltage value, the voltage value of the first output voltage is greater than the voltage value of the second output voltage.