Dual-power supply circuit of data storage unit and fire alarm equipment

Abstract

The utility model relates to a dual-power supply circuit of a data storage unit and fire alarm equipment. A dual-power supply circuit of the data storage unit comprises a first diode, when a USB power supply and a mainboard power supply are connected at the same time, the first diode outputs the mainboard power supply to a forbidden end of a USB power supply detection circuit, and the USB power supply detection circuit is controlled to stop working, so that the mainboard power supply can supply power; and then the mainboard power supply detection circuit detects the mainboard power supply and controls the USB power supply switching circuit to be switched off, so that the USB power supply is prevented from supplying power.

Description

Technical Field

[0001] The present invention relates to the field of fire alarm equipment, in particular to a dual-power supply circuit of a data storage unit and fire alarm equipment. Background Art

[0002] A data storage unit needs to be installed in the fire alarm controller. The data storage unit needs to store the fire alarm controller operating data and provide a USB interface for data export. The data storage unit needs to have the ability to automatically switch between two power supplies. At the same time, the standard also requires that the power supply must have anti-reverse polarity protection function.

[0003] The commonly used automatic power supply switching solution is implemented using a rectifier diode. However, there will be some tube voltage drop during the conduction process of the rectifier diode, and the tube voltage drop changes dynamically with the change of current. The greater the current, the greater the tube voltage drop. Unstable and low power supply voltage will affect the normal operation of the chip inside the data storage unit, especially in places with harsh electromagnetic compatibility environments. The unstable power supply will cause the data storage unit to freeze. Summary of the Invention

[0004] Aiming at the problem of how to power a data storage unit, the present invention proposes a dual power supply circuit for the data storage unit and a fire alarm device.

[0005] In a first aspect, the present application provides a dual power supply circuit for a data storage unit, the dual power supply circuit comprising:

[0006] A mainboard power switch circuit, wherein the input end is connected to the mainboard power end, and the output end of the mainboard power switch circuit is connected to the data storage unit;

[0007] A USB power switch circuit, wherein the input end is connected to the USB power end, and the output end of the USB power switch circuit is connected to the data storage unit;

[0008] A mainboard power detection circuit, wherein a detection end is connected to the mainboard power end, and an output end of the mainboard power detection circuit is connected to a controlled end of the USB power switch circuit; when the mainboard power detection circuit detects that the mainboard power is on, the USB power switch circuit is controlled to be disconnected;

[0009] A first diode, the anode of which is connected to the power supply terminal of the mainboard; and

[0010] A USB power detection circuit, wherein a prohibition end is connected to the cathode of the first diode, a detection end of the USB power detection circuit is connected to the USB power end, and an output end of the USB power detection circuit is connected to the controlled end of the mainboard power switch circuit;

[0011] When the prohibition terminal of the USB power detection circuit detects the mainboard power supply, the USB power detection circuit prohibits detecting the USB power supply;

[0012] When the inhibiting end of the USB power detection circuit does not detect the mainboard power supply, the USB power detection circuit detects the USB power supply, and when the USB power supply is detected, controls the mainboard power switch circuit to be disconnected.

[0013] In some embodiments, the USB power detection circuit includes: a first switching tube and a first resistor; wherein, the input end of the first switching tube is connected to the USB power end, and the output end of the first switching tube is connected to the controlled end of the mainboard power switch circuit; the controlled end of the first switching tube is connected to one end of the first resistor, and the other end of the first resistor is grounded.

[0014] In some embodiments, the common end of the first resistor and the first switch tube is the disable end, and the disable end is connected to the cathode of the first diode; when the disable end of the USB power detection circuit detects the motherboard power supply, the first switch tube is disconnected to disable the detection of the USB power supply.

[0015] In some embodiments, the USB power switch circuit is a self-starting switch circuit, and the USB power switch circuit includes: a second switch tube, a second diode, a third diode, a second resistor, and a third resistor; wherein,

[0016] The input end of the second switch tube is connected to the USB power supply end, the output end of the second switch tube is connected to the data storage unit, the controlled end of the second switch tube is connected to one end of the second resistor, the other end of the second resistor is connected to the anode of the second diode, and the cathode of the second diode is grounded;

[0017] One end of the third resistor is connected to the output end of the second switch tube, and the other end of the third resistor is connected to the controlled end of the second switch tube;

[0018] The cathode of the third diode is connected to the output end of the second switch tube, and the anode of the third diode is connected to the controlled end of the second switch tube.

[0019] In some embodiments, the mainboard power switch circuit is a self-opening switch circuit, and the mainboard power switch circuit includes: a third switch tube, a fourth resistor, a fifth resistor, a fourth diode, and a fifth diode; wherein,

[0020] The input end of the third switch tube is connected to the mainboard power supply end, the output end of the third switch tube is connected to the data storage unit, the controlled end of the third switch tube is connected to one end of the fifth resistor, the other end of the fifth resistor is connected to the anode of the fifth diode, and the cathode of the fifth diode is grounded;

[0021] One end of the fourth resistor is connected to the output end of the third switch tube, and the other end of the fourth resistor is connected to the controlled end of the third switch tube;

[0022] The cathode of the fourth diode is connected to the output end of the third switch tube, and the anode of the fourth diode is connected to the controlled end of the third switch tube.

[0023] In some embodiments, the mainboard power detection circuit includes: a fourth switch tube and a sixth resistor;

[0024] The input end of the fourth switch tube is connected to the mainboard power end, and the output end of the fourth switch tube is connected to the controlled end of the USB power switch circuit; the controlled end of the fourth switch tube is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded.

[0025] In some embodiments, the first switch tube and the fourth switch tube are PNP transistors;

[0026] In some embodiments, the second switch transistor and the third switch transistor are NMOS transistors.

[0027] In some embodiments, a voltage stabilizing circuit is further included, and the voltage stabilizing circuit includes: a sixth diode, a seventh diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, and a low voltage dropout regulator; wherein,

[0028] The anode of the sixth diode is connected to the USB power supply terminal, the cathode of the sixth diode is connected to the input terminal of the low-voltage dropout regulator, and the output terminal of the low-voltage dropout regulator is connected to the input terminal of the USB power switch circuit;

[0029] One end of the seventh diode is connected to the input end of the low voltage dropout regulator, and the other end of the seventh diode is grounded;

[0030] The first end of the first capacitor and the first end of the second capacitor are both connected to the output end of the low-dropout regulator, and the second end of the first capacitor and the second end of the second capacitor are grounded;

[0031] The first end of the third capacitor and the first end of the fourth capacitor are both connected to the input end of the low-dropout regulator, and the second end of the third capacitor and the second end of the fourth capacitor are grounded.

[0032] The present application also proposes a fire alarm device, comprising:

[0033] A board-to-board interface connected to the mainboard power supply terminal to output mainboard power to the mainboard power supply terminal;

[0034] A USB interface connected to the USB power supply terminal to access an externally provided USB power supply to the USB power supply terminal; a data storage unit; a controller; and a dual power supply circuit of the data storage unit as described above, the dual power supply circuit of the data storage unit being connected to the data storage unit.

[0035] In some embodiments, the USB interface includes: a power supply end, which is connected to the USB power supply end; and a data transmission end, which is used for connecting the controller to an external device to export controller operation data to the external device.

[0036] When the dual power supply circuit of the embodiment of the present invention is connected to the mainboard power supply, the mainboard power supply is input to the mainboard power switch circuit through the board-to-board interface, controlling the mainboard power switch circuit to turn on to supply power to the data storage unit; when the mainboard power detection circuit detects the mainboard power supply, it controls the USB power switch circuit to turn off to prevent the USB power supply from supplying power. When the USB power supply is connected, the USB power supply is input to the USB power switch circuit through the USB interface and the voltage stabilizing circuit, controlling the USB power switch circuit to turn on to supply power to the data storage unit. At the same time, the USB power detection circuit detects the USB power supply and controls the mainboard power switch circuit to turn off to prevent the mainboard power supply from supplying power. When the USB power supply and the mainboard power supply are connected at the same time, the first diode outputs the mainboard power supply to the inhibit terminal of the USB power detection circuit, controlling the USB power detection circuit to stop working, allowing the mainboard power supply to supply power. Then, the mainboard power detection circuit detects the mainboard power and controls the USB power switch circuit to turn off to prevent the USB power supply from supplying power. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a circuit block diagram of an embodiment of a dual power supply circuit for a data storage unit of the present application;

[0038] Figure 2 This is a circuit block diagram of another embodiment of the dual power supply circuit of the data storage unit of the present application.

[0039] Figure 3 This is a circuit diagram of an embodiment of a dual power supply circuit for a data storage unit of the present application.

[0040] The accompanying figures are as follows:

[0041] 11 Mainboard power detection circuit; 12 Mainboard power switch circuit;

[0042] 13USB power detection circuit; 14USB power switch circuit;

[0043] 20 voltage stabilizing circuit; 30 board-to-board interface;

[0044] 40USB interfaces; 50data storage units;

[0045] D1~D7 are the first to seventh diodes; Q1~Q4 are the first to fourth switching tubes;

[0046] R1~R6 are the first to sixth resistors. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the specified features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0049] In the description of the present invention, the term "for example" is used to mean "used as an example, illustration or illustration". Any embodiment of the present invention described as "for example" is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is given to enable any person skilled in the art to implement and use the present invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other examples, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the present invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed herein.

[0050] Example 1

[0051] Reference Figure 1 , the data storage unit 50 of the present application can be connected to a USB power supply and a motherboard power supply.

[0052] The present application provides a dual power supply circuit for a data storage unit 50, which realizes automatic switching between USB power supply and motherboard power supply.

[0053] Reference Figure 2 In one embodiment, the dual power supply circuit includes:

[0054] The mainboard power switch circuit 12 has an input end connected to the mainboard power end, and an output end connected to the data storage unit 50;

[0055] A USB power switch circuit 14, the input end of which is connected to the USB power end, and the output end of the USB power switch circuit 14 is connected to the data storage unit 50;

[0056] A motherboard power detection circuit 11, wherein the detection end is connected to the motherboard power end, and the output end of the motherboard power detection circuit 11 is connected to the controlled end of the USB power switch circuit 14; when the motherboard power detection circuit 11 detects that the motherboard power is on, the USB power switch circuit 14 is turned off;

[0057] A first diode D1, the anode of which is connected to the mainboard power supply terminal; and

[0058] A USB power detection circuit 13, wherein the inhibiting end is connected to the cathode of the first diode D1, the detecting end of the USB power detection circuit 13 is connected to the USB power end, and the output end of the USB power detection circuit 13 is connected to the controlled end of the mainboard power switch circuit 12;

[0059] When the prohibition terminal of the USB power detection circuit 13 detects the mainboard power supply, the USB power detection circuit 13 prohibits detecting the USB power supply;

[0060] When the inhibiting end of the USB power detection circuit 13 does not detect the mainboard power supply, the USB power detection circuit 13 detects the USB power supply, and when the USB power supply is detected, controls the mainboard power switch circuit 12 to be turned off.

[0061] In this embodiment, when the motherboard power supply is connected, the motherboard power supply is input to the motherboard power switch circuit 12 through the board-to-board interface 30, controlling the motherboard power switch circuit 12 to turn on and supply power to the data storage unit 50. The motherboard power detection circuit 11 detects the motherboard power supply and then controls the USB power switch circuit 14 to turn off, preventing the USB power supply from being supplied. When the USB power supply is connected, the USB power supply is input to the USB power switch circuit 14 through the USB interface 40 and the voltage regulator circuit 20, controlling the USB power switch circuit 14 to turn on and supply power to the data storage unit 50. At the same time, the USB power detection circuit 13 detects the USB power supply and controls the motherboard power switch circuit 12 to turn off, preventing the motherboard power supply from being supplied. When both the USB power supply and the motherboard power supply are connected at the same time, the first diode D1 outputs the motherboard power supply to the disable terminal of the USB power detection circuit 13, controlling the USB power detection circuit 13 to stop working, allowing the motherboard power supply to be supplied. Then, the motherboard power detection circuit 11 detects the motherboard power and then controls the USB power switch circuit 14 to turn off, preventing the USB power supply from being supplied.

[0062] Reference Figure 3 In some embodiments, the USB power detection circuit 13 includes: a first switch tube Q1 and a first resistor R1; wherein, the input end of the first switch tube Q1 is connected to the USB power end, and the output end of the first switch tube Q1 is connected to the controlled end of the motherboard power switch circuit 12; the controlled end of the first switch tube Q1 is connected to one end of the first resistor R1, and the other end of the first resistor R1 is grounded.

[0063] The first switch tube Q1 is a PNP transistor, which is turned on when the controlled end (base) is at a low level (or the base of the PNP transistor is lower than the emitter voltage), and is cut off when the high level is applied. Therefore, when the input end is connected to a USB power supply, the first switch tube Q1 is turned on, thereby pulling up the controlled end of the motherboard power switch circuit 12, causing the motherboard power switch circuit 12 to be cut off.

[0064] Reference Figure 3 In some embodiments, the common end of the first resistor R1 and the first switch tube Q1 is the disable end, and the disable end is connected to the cathode of the first diode D1; when the disable end of the USB power detection circuit 13 detects the motherboard power supply, the first switch tube Q1 is disconnected to disable the detection of the USB power supply.

[0065] In this embodiment, the motherboard power supply pulls up the controlled end level of the first switch tube Q1 through the first diode D1, so that the first switch tube Q1 is turned off. With this setting, even if the input end is connected to the USB power supply, the first switch tube Q1 cannot pull up the controlled end of the motherboard power switch circuit 12.

[0066] Reference Figure 3 In some embodiments, the USB power switch circuit 14 is a self-starting switch circuit, comprising: a second switch tube Q2, a second diode D2, a third diode D3, a second resistor R2, and a third resistor R3; wherein the input end of the second switch tube Q2 is connected to the USB power end, the output end of the second switch tube Q2 is connected to the data storage unit 50, the controlled end of the second switch tube Q2 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to the anode of the second diode D2, and the cathode of the second diode D2 is grounded; one end of the third resistor R3 is connected to the output end of the second switch tube Q2, the other end of the third resistor R3 is connected to the controlled end of the second switch tube Q2; the cathode of the third diode D3 is connected to the output end of the second switch tube Q2, and the anode of the third diode D3 is connected to the controlled end of the second switch tube Q2.

[0067] In this embodiment, the second switch tube Q2 is an NMOS tube, which is turned on when VGS (the gate-source voltage difference) is greater than the threshold and turned off when it is less than the threshold. With this configuration, when USB power is detected, the second switch tube Q2 is turned on; however, when the controlled end is pulled high by the USB power detection circuit 13, it cannot be turned on.

[0068] The second diode D2 is used for power reverse protection, and the third diode D3 is used to limit the damage of the second switch tube Q2 caused by excessive voltage, thereby protecting the second switch tube Q2.

[0069] Reference Figure 3 In some embodiments, the motherboard power switch circuit 12 is a self-opening switch circuit, and the motherboard power switch circuit 12 includes: a third switch tube Q3, a fourth resistor R4, a fifth resistor R5, a fourth diode D4, and a fifth diode D5; wherein,

[0070] The input end of the third switch tube Q3 is connected to the mainboard power supply end, the output end of the third switch tube Q3 is connected to the data storage unit 50, the controlled end of the third switch tube Q3 is connected to one end of the fifth resistor R5, the other end of the fifth resistor R5 is connected to the anode of the fifth diode D5, and the cathode of the fifth diode D5 is grounded;

[0071] One end of the fourth resistor R4 is connected to the output end of the third switch tube Q3, and the other end of the fourth resistor R4 is connected to the controlled end of the third switch tube Q3;

[0072] A cathode of the fourth diode D4 is connected to the output end of the third switch tube Q3 , and an anode of the fourth diode D4 is connected to the controlled end of the third switch tube Q3 .

[0073] In this embodiment, the third switch tube Q3 is an NMOS tube, which is turned on when VGS (the gate-source voltage difference) is greater than the threshold and turned off when it is less than the threshold. With this setting, when USB power is detected, the third switch tube Q3 is turned on; however, when the controlled end is pulled high by the motherboard power detection circuit 11, it cannot be turned on.

[0074] The fourth diode D4 is used for power reverse protection. The fifth diode D5 is used to limit the damage of the second switch tube Q2 caused by excessive voltage, thereby protecting the second switch tube Q2.

[0075] Reference Figure 3 In some embodiments, the motherboard power detection circuit 11 includes: a fourth switch tube Q4 and a sixth resistor R6; the input end of the fourth switch tube Q4 is connected to the motherboard power end, and the output end of the fourth switch tube Q4 is connected to the controlled end of the USB power switch circuit 14; the controlled end of the fourth switch tube Q4 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is grounded.

[0076] In this embodiment, the fourth switch tube Q4 is a PNP transistor, which is turned on when the controlled terminal (base) is at a low level (or the base of the PNP transistor is lower than the emitter voltage) and is cut off when the controlled terminal is at a high level. Therefore, when the input terminal is connected to the USB power supply, the fourth switch tube Q4 is turned on, thereby pulling up the controlled terminal of the USB power switch circuit 14, so that the USB power switch circuit 14 is cut off.

[0077] Reference Figure 3 In the above embodiment, the first switch tube Q1 and the fourth switch tube Q4 are PNP transistors; the base of the PNP transistor is defined as the controlled end, the emitter is the input end, and the collector is the output end.

[0078] Reference Figure 3 In some embodiments, the second switch transistor Q2 and the third switch transistor Q3 are NMOS transistors, where the gate of the NMOS transistor is defined as the controlled terminal, the source is defined as the input terminal, and the drain is defined as the output terminal.

[0079] In some embodiments, a voltage stabilizing circuit 20 is further included, and the voltage stabilizing circuit 20 includes: a sixth diode D6, a seventh diode D6, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a low voltage dropout regulator; wherein, the anode of the sixth diode D6 is connected to the USB power supply terminal, the cathode of the sixth diode D6 is connected to the input terminal of the low voltage dropout regulator, and the output terminal of the low voltage dropout regulator is connected to the input terminal of the USB power switch circuit 14; one end of the seventh diode D6 is connected to the input terminal of the low voltage dropout regulator, and the other end of the seventh diode D6 is grounded; the first end of the first capacitor and the first end of the second capacitor are both connected to the output terminal of the low voltage dropout regulator, and the second end of the first capacitor and the second end of the second capacitor are grounded; the first end of the third capacitor and the first end of the fourth capacitor are both connected to the input terminal of the low voltage dropout regulator, and the second end of the third capacitor and the second end of the fourth capacitor are grounded.

[0080] In this embodiment, the low-dropout voltage regulator can step down the USB power supply to 3.3V to power the data storage unit 50. The first, second, third, and fourth capacitors are all decoupling capacitors. The sixth diode D6 can prevent reverse connection, and the seventh diode D6 can provide overvoltage protection.

[0081] Example 2

[0082] The present application also proposes a fire alarm device, comprising:

[0083] A board-to-board interface 30 connected to the mainboard power terminal to output mainboard power to the mainboard power terminal;

[0084] A USB interface 40 is connected to the USB power supply terminal to connect an externally provided USB power supply to the USB power supply terminal; a data storage unit 50; a controller; and a dual power supply circuit of the data storage unit 50 as described above, the dual power supply circuit of the data storage unit 50 is connected to the data storage unit 50.

[0085] In this embodiment, the dual power supply circuit of the data storage unit 50 refers to the structural design and effects of the above-mentioned embodiment.

[0086] In some embodiments, the USB interface 40 includes: a power supply end, which is connected to the USB power supply end; and a data transmission end, which is used for connecting the controller to an external device to export controller operation data to the external device.

[0087] It should be noted that, in the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0088] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0089] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0090] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0091] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0092] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0093] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A dual power supply circuit for a data storage unit, characterized in that: include: A mainboard power switch circuit, wherein the input end is connected to the mainboard power end, and the output end of the mainboard power switch circuit is connected to the data storage unit; A USB power switch circuit, wherein the input end is connected to the USB power end, and the output end of the USB power switch circuit is connected to the data storage unit; A mainboard power detection circuit, wherein a detection end is connected to the mainboard power end, and an output end of the mainboard power detection circuit is connected to a controlled end of the USB power switch circuit; when the mainboard power detection circuit detects that the mainboard power is on, the USB power switch circuit is controlled to be disconnected; A first diode, the anode of which is connected to the power supply terminal of the mainboard; as well as A USB power detection circuit, wherein a prohibition end is connected to the cathode of the first diode, a detection end of the USB power detection circuit is connected to the USB power end, and an output end of the USB power detection circuit is connected to the controlled end of the mainboard power switch circuit; When the prohibition terminal of the USB power detection circuit detects the mainboard power supply, the USB power detection circuit prohibits detecting the USB power supply; When the inhibiting end of the USB power detection circuit does not detect the mainboard power supply, the USB power detection circuit detects the USB power supply, and when the USB power supply is detected, controls the mainboard power switch circuit to be disconnected.

2. The dual power supply circuit of the data storage unit according to claim 1, wherein: The USB power detection circuit includes: a first switch tube and a first resistor; wherein, The input end of the first switch tube is connected to the USB power end, and the output end of the first switch tube is connected to the controlled end of the mainboard power switch circuit; the controlled end of the first switch tube is connected to one end of the first resistor, and the other end of the first resistor is grounded.

3. The dual power supply circuit of the data storage unit according to claim 2, wherein: The common end of the first resistor and the first switch tube is a disable end of the USB power detection circuit, and the disable end is connected to the cathode of the first diode; When the prohibition end detects the mainboard power supply, the first switch tube is disconnected to prohibit the detection of the USB power supply.

4. The dual power supply circuit of the data storage unit according to claim 3, characterized in that: The USB power switch circuit is a self-starting switch circuit, and the USB power switch circuit includes: a second switch tube, a second diode, a third diode, a second resistor and a third resistor; wherein, The input end of the second switch tube is connected to the USB power supply end, the output end of the second switch tube is connected to the data storage unit, the controlled end of the second switch tube is connected to one end of the second resistor, the other end of the second resistor is connected to the anode of the second diode, and the cathode of the second diode is grounded; One end of the third resistor is connected to the output end of the second switch tube, and the other end of the third resistor is connected to the controlled end of the second switch tube; The cathode of the third diode is connected to the output end of the second switch tube, and the anode of the third diode is connected to the controlled end of the second switch tube.

5. The dual power supply circuit of the data storage unit according to claim 4, characterized in that: The mainboard power switch circuit is a self-opening switch circuit, and the mainboard power switch circuit includes: a third switch tube, a fourth resistor, a fifth resistor, a fourth diode and a fifth diode; wherein, The input end of the third switch tube is connected to the mainboard power supply end, the output end of the third switch tube is connected to the data storage unit, the controlled end of the third switch tube is connected to one end of the fifth resistor, the other end of the fifth resistor is connected to the anode of the fifth diode, and the cathode of the fifth diode is grounded; One end of the fourth resistor is connected to the output end of the third switch tube, and the other end of the fourth resistor is connected to the controlled end of the third switch tube; The cathode of the fourth diode is connected to the output end of the third switch tube, and the anode of the fourth diode is connected to the controlled end of the third switch tube.

6. The dual power supply circuit of the data storage unit according to claim 5, characterized in that: The mainboard power detection circuit includes: a fourth switch tube and a sixth resistor; The input end of the fourth switch tube is connected to the mainboard power end, and the output end of the fourth switch tube is connected to the controlled end of the USB power switch circuit; the controlled end of the fourth switch tube is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded.

7. The dual power supply circuit of the data storage unit according to claim 6, wherein: The first switching tube and the fourth switching tube are PNP transistors; The second switch tube and the third switch tube are NMOS tubes.

8. The dual power supply circuit of the data storage unit according to claim 1, wherein: It also includes a voltage stabilizing circuit, which includes: a sixth diode, a seventh diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a low voltage dropout regulator; wherein, The anode of the sixth diode is connected to the USB power supply terminal, the cathode of the sixth diode is connected to the input terminal of the low-voltage dropout regulator, and the output terminal of the low-voltage dropout regulator is connected to the input terminal of the USB power switch circuit; One end of the seventh diode is connected to the input end of the low voltage dropout regulator, and the other end of the seventh diode is grounded; The first end of the first capacitor and the first end of the second capacitor are both connected to the output end of the low-dropout regulator, and the second end of the first capacitor and the second end of the second capacitor are grounded; The first end of the third capacitor and the first end of the fourth capacitor are both connected to the input end of the low-dropout regulator, and the second end of the third capacitor and the second end of the fourth capacitor are grounded.

9. A fire alarm device, characterized in that: include: A board-to-board interface, connected to the mainboard power terminal, to output the mainboard power to the mainboard power terminal; A USB interface is connected to the USB power supply terminal to connect an external USB power supply to the USB power supply terminal; Data storage unit; Controller; as well as The dual power supply circuit of the data storage unit according to any one of claims 1 to 8, wherein the dual power supply circuit of the data storage unit is connected to the data storage unit.

10. The fire alarm device according to claim 9, characterized in that: The USB interface includes: A power supply terminal connected to the USB power supply terminal; A data transmission end is used for connecting the controller to an external device to export controller operation data to the external device.

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