Low-power-consumption high-decibel sound alarm circuit and sound alarm

Abstract

The utility model relates to a low-power-consumption high-decibel sound alarm circuit and a sound alarm. The low-power-consumption high-decibel sound alarm circuit comprises a power supply circuit, a control circuit and a sound output circuit, the power supply circuit is used for supplying power to the control circuit; the control circuit is used for controlling sound pressure output of the sound output circuit; the sound output circuit comprises a first MOS tube, a second MOS tube, a capacitor group and an inductor. The control circuit is respectively connected with the first MOS tube and the second MOS tube, the first MOS tube is also connected with the capacitor bank, the second MOS tube and the capacitor bank are respectively connected with the inductor, and the inductor is also connected with a buzzer; the charging state of the capacitor bank is switched by controlling the on or off of the first MOS tube; when the second MOS tube is switched on, the inductor enters a charging state, and when the second MOS tube is switched off, the inductor outputs high voltage to the buzzer; the output sound pressure level can be effectively improved, so that larger sound pressure is output, the alarm prompting effect is obviously improved, the power consumption is reduced, and the use performance is better.

Description

Technical Field

[0001] This utility model relates to the field of fire alarm technology, and more specifically, to a low-power, high-decibel sound alarm circuit and sound alarm device. Background Technology

[0002] In fire alarm systems, audible sirens serve as signaling devices, primarily alerting people to the occurrence of a fire and urging them to evacuate to a safe location immediately. To ensure the effectiveness of the alarm, the design of audible sirens considers factors such as sound intensity, frequency, and directionality. The decibel level of an audible sirens is a crucial factor affecting its alarm effectiveness, especially in noisy environments such as factories and construction sites, where high-decibel sirens are needed to effectively convey the alarm information and prompt people to evacuate quickly.

[0003] Currently, most commercially available sirens have a sound pressure level of approximately 80dB at 3 meters. Some products may only reach 75dB in one direction. This is mainly because current circuit designs use transformers to convert voltage to power the buzzer. Figure 1 As shown, the switching signal is converted by optocoupler U6, and then the level is converted on transformer T1 to power the buzzer. This results in a lot of energy loss during the conversion process, which prevents the sound pressure value from being increased. It is also costly and consumes a lot of power. Although it may be sufficient in a relatively quiet environment, the alarm effect is poor in noisy or chaotic scenarios, and it is difficult to remind people to evacuate in time. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a low-power, high-decibel sound alarm circuit and sound alarm device, which addresses the above-mentioned deficiencies of the prior art.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] On one hand, this utility model provides a low-power, high-decibel sound alarm circuit, including a power supply circuit, a control circuit, and a sound output circuit; the power supply circuit is used to supply power to the control circuit, and the control circuit is used to control the sound pressure output of the sound output circuit; the sound output circuit includes a first MOSFET, a second MOSFET, a capacitor bank, and an inductor; the control circuit is connected to the first MOSFET and the second MOSFET respectively, the first MOSFET is also connected to the capacitor bank, the second MOSFET and the capacitor bank are also connected to the inductor respectively, and the inductor is also connected to a buzzer; the charging state of the capacitor bank is switched by controlling the conduction or cutoff of the first MOSFET; when the second MOSFET is on, the inductor enters the charging state, and when the second MOSFET is off, the inductor outputs high voltage to the buzzer.

[0007] In some embodiments, the sound output circuit further includes a first transistor, which is connected to a first MOSFET and a control circuit respectively. When the control circuit controls the first transistor to conduct, the first MOSFET also conducts.

[0008] In some embodiments, the sound output circuit further includes a first rectifier connected to a first MOS transistor.

[0009] In some embodiments, the capacitor bank includes a first electrolytic capacitor and a second electrolytic capacitor, the first electrolytic capacitor and the second electrolytic capacitor being connected to a first MOSFET respectively.

[0010] In some embodiments, the power supply circuit includes a second rectifier, a second transistor, a third transistor, and a power supply chip; the second rectifier is connected to the second transistor and the third transistor respectively, the second transistor is also connected to the third transistor, and the third transistor is also connected to the power supply chip.

[0011] In some embodiments, the power supply circuit further includes a first resistor, a second resistor, and a Zener diode; one end of the second rectifier is connected to one end of the first resistor and one end of the second resistor, the other end of the first resistor is connected to the base of the second transistor and the cathode of the Zener diode, and the anode of the Zener diode is grounded; the other end of the second resistor is connected to the collector of the second transistor and the third transistor, the emitter of the second transistor is connected to the base of the third transistor, and the emitter of the third transistor is connected to the power supply chip.

[0012] In some embodiments, the control circuit includes an MCU chip, the MCU chip includes a charging signal transmission terminal and an acoustic signal transmission terminal, the charging signal transmission terminal is connected to a first transistor, and the acoustic signal transmission terminal is connected to a second MOSFET.

[0013] In some embodiments, the frequency range of the sweep output of the sound output circuit is 1.8K to 3.5K.

[0014] On the other hand, the present invention also provides an audible alarm, including a low-power, high-decibel audible alarm circuit as described in any of the preceding claims.

[0015] In some embodiments, the system further includes a housing and a circuit board. A sound outlet is provided on one side of the housing, and the buzzer is located at the sound outlet. The circuit board is located inside the housing, and the low-power high-decibel sound alarm circuit is located on the circuit board and connected to the buzzer.

[0016] The beneficial effects of this utility model are as follows: Unlike the prior art, the low-power high-decibel sound alarm circuit of this utility model can switch the charging state of the capacitor bank by controlling the conduction or cutoff of the first MOSFET, which helps to reduce power consumption; by controlling the conduction or cutoff of the second MOSFET, the working state of the inductor can be controlled. When the second MOSFET is on, the inductor enters the charging state; when the second MOSFET is off, the inductor outputs high voltage to the buzzer, which can effectively improve the output sound pressure level, thereby outputting a larger sound pressure, significantly improving the alarm prompting effect, and having better performance. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an existing audible alarm circuit mentioned in the background section;

[0018] Figure 2 This is a circuit diagram of the power supply circuit in an embodiment of this utility model;

[0019] Figure 3 This is a circuit diagram of the control circuit in an embodiment of this utility model;

[0020] Figure 4 This is a circuit diagram of the sound output circuit in an embodiment of this utility model;

[0021] Figure 5 This is a logic diagram illustrating the change of the duty cycle of the MUSIC signal in an embodiment of this utility model;

[0022] Figure 6 This is a schematic diagram of the overall structure of the audible alarm in an embodiment of this utility model;

[0023] Figure 7 This is an exploded structural diagram of the audible alarm in an embodiment of this utility model;

[0024] Figure 8 This is a cross-sectional structural diagram of the audible alarm in an embodiment of this utility model;

[0025] The labels and numbers in the diagram are as follows: Power supply circuit-1; Control circuit-2; Sound output circuit-3; Capacitor group-301; Housing-10; Circuit board-20; Buzzer housing-31; Buzzer plate-32; Speaker-40. Detailed Implementation

[0026] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this utility model are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the present invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] "Multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0029] Furthermore, the terms indicating orientation, such as "up," "down," "front," "back," "left," "right," "upper end," and "lower end," are all based on the posture and position of the device or equipment described in this solution during normal use.

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of this utility model. Obviously, the described embodiments are some, but not all, embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0031] Example 1: This embodiment of the present invention provides a low-power, high-decibel audible alarm circuit, such as... Figures 2 to 5As shown, the low-power, high-decibel sound alarm circuit includes a power supply circuit 1, a control circuit 2, and a sound output circuit 3. The power supply circuit 1 supplies power to the control circuit 2, and the control circuit 2 controls the sound pressure output of the sound output circuit 3. The sound output circuit 3 includes a first MOSFET Q6, a second MOSFET Q10, a capacitor bank 301, and an inductor L2. The control circuit 2 is connected to the first MOSFET Q6 and the second MOSFET Q10, respectively. The first MOSFET Q6 is also connected to the capacitor bank 301, and the second MOSFET Q10 and the capacitor bank 301 are also connected to the inductor L2. The inductor L2 is also connected to a buzzer B1. The charging state of the capacitor bank 301 is switched by controlling the first MOSFET Q6 to be on or off. When the second MOSFET Q10 is on, the inductor L2 enters the charging state; when the second MOSFET Q10 is off, the inductor L2 outputs high voltage to the buzzer B1.

[0032] In this embodiment, the sound output circuit 3 further includes a first transistor Q9, which is connected to both the first MOSFET Q6 and the control circuit 2. When the control circuit 2 turns on the first transistor Q9, the first MOSFET Q6 also turns on. Furthermore, the sound output circuit 3 also includes a first rectifier DB3, which is connected to the first MOSFET Q6. The capacitor bank 301 includes a first electrolytic capacitor C12 and a second electrolytic capacitor C13, which are connected to the first MOSFET Q6. For the specific circuit layout of the sound output circuit 3, please refer to [link to specific circuit diagram]. Figure 4 .

[0033] It should be noted that, depending on the specific application requirements, Figure 4 The application of resistor R16 shown is adjustable. Resistor R16 is a 0Ω resistor, when... Figure 4 After the connection is complete, the first electrolytic capacitor C12 and the second electrolytic capacitor C13 will always be in a charging state. Therefore, if strict control of power consumption is required, resistor R16 needs to be removed to enable control circuit 2 to control the on / off state of the first MOSFET Q6.

[0034] In this embodiment, the power supply circuit 1 uses a two-wire power supply and can directly use DC24V for power supply without communication, which can save on engineering wiring. Specifically, the power supply circuit 1 includes a second rectifier DB1, a second transistor Q1, a third transistor Q4, and a power supply chip U1; the second rectifier DB1 is connected to both the second transistor Q1 and the third transistor Q4, the second transistor Q1 is also connected to the third transistor Q4, and the third transistor Q4 is also connected to the power supply chip U1. Furthermore, the power supply circuit 1 also includes a first resistor R1, a second resistor R2, and a Zener diode ZD1; one end of the second rectifier DB1 is connected to one end of the first resistor R1 and one end of the second resistor R2, respectively; the other end of the first resistor R1 is connected to the base of the second transistor Q1 and the cathode of the Zener diode ZD1, respectively, and the anode of the Zener diode ZD1 is grounded; the other end of the second resistor R2 is connected to the collectors of the second transistor Q1 and the third transistor Q4, respectively; the emitter of the second transistor Q1 is connected to the base of the third transistor Q4, and the emitter of the third transistor Q4 is connected to the power supply chip U1. For the specific circuit layout of the power supply circuit 1, please refer to [link to specific circuit diagram]. Figure 2 .

[0035] In this embodiment, the control circuit 2 includes an MCU chip U2. The MCU chip U2 includes a charging signal transmission terminal Charging2 and a sound signal transmission terminal MUSIC. The charging signal transmission terminal Charging2 is connected to a first transistor Q9 to control the conduction or cutoff of the first transistor Q9; the sound signal transmission terminal MUSIC is connected to a second MOSFET Q10 to control the conduction or cutoff of the second MOSFET Q10. For the specific circuit layout of the control circuit 2, please refer to [link to relevant documentation]. Figure 3 .

[0036] In this embodiment, the frequency range of the sweep output of the sound output circuit 3 is 1.8K to 3.5K.

[0037] The low-power, high-decibel sound alarm circuit of this embodiment can be applied to a sound alarm. The following describes the working principle of the low-power, high-decibel sound alarm circuit in a sound alarm in a specific implementation, with reference to the low-power, high-decibel sound alarm circuit provided in Embodiment 1:

[0038] When the audible alarm is powered on, the charging signal transmission terminal Charging2 outputs a high level, controlling the first transistor Q9 to conduct. After conduction, there will be a voltage difference of about 15.4V between the gate and source of the first MOSFET Q6. At this time, the first MOSFET Q6 conducts, charging the first electrolytic capacitor C12 and the second electrolytic capacitor C13.

[0039] When the audible alarm receives a control command from the automatic alarm system and is activated, the MUSIC sound signal transmission terminal will output an analog PWM wave to control the on / off state of the second MOSFET Q10. When the MUSIC sound signal transmission terminal outputs a high level, the second MOSFET Q10 is turned on. At this time, the drain and source of the second MOSFET Q10 are in a low-impedance state, that is, Q10_D is GND. At this time, the inductor L2 is charged and stored through the charge released by the first electrolytic capacitor C12 and the second electrolytic capacitor C13. When the MUSIC sound signal transmission terminal outputs a low level, the second MOSFET Q10 is turned off. At this time, the inductor L2 and the buzzer form a path to release the energy stored in the inductor L2. The greater the energy stored in the inductor L2, the higher the energy output to the buzzer B1, resulting in a greater sound pressure level output by the buzzer B1.

[0040] The audible alarm outputs a frequency sweep between 1.8kHz and 3.5kHz. Buzzer B1 has a resonant frequency point; the sound pressure level of buzzer B1 is maximized only when the control frequency reaches this resonant frequency point. To control power consumption, the duty cycle of the MUSIC signal transmission terminal increases only when the frequency reaches the resonant frequency point. At normal frequencies, the duty cycle is 1 / 8; at the resonant frequency point, the duty cycle doubles. This increased duty cycle lengthens the charging time of inductor L2, resulting in a higher reverse output voltage from inductor L2 when buzzer B1 reaches its resonant frequency, thus maximizing the sound pressure level of buzzer B1. The timing of the duty cycle change in the MUSIC signal transmission terminal is as follows: Figure 5 As shown.

[0041] Example 2: This utility model embodiment also provides an audible alarm, which includes the low-power high-decibel audible alarm circuit provided in Example 1.

[0042] Furthermore, such as Figures 6 to 8 As shown, the sound alarm also includes a housing 10 and a circuit board 20. A sound outlet is provided on one side of the housing 10, and a buzzer is located at the sound outlet. The circuit board 20 is located inside the housing 10 and below the buzzer. A low-power high-decibel sound alarm circuit is located on the circuit board 20, and the buzzer is electrically connected to the low-power high-decibel sound alarm circuit.

[0043] Specifically, the buzzer includes a buzzer housing 31 and a buzzer plate 32. The buzzer housing 31 has a resonance cavity inside, and the buzzer plate 32 is located inside the resonance cavity. The resonance cavity directly faces the outside through the sound outlet, which helps to reduce the propagation path and reduce sound pressure attenuation. Among them, the buzzer plate 32 is selected with a large size, which can better improve the sound pressure of the sound source. Combined with a suitable resonance cavity, the sound pressure level emitted is significantly improved.

[0044] The housing 10 also has a speaker 40 on the side with the sound outlet. The sound outlet is located inside the speaker 40's horn opening, used to focus and amplify the sound to increase the sound pressure and further achieve the amplification effect. Both the housing 10 and the speaker 40 are made of suitable rigid materials. Rigid materials have high sound reflectivity and mainly play the role of reflecting and conducting sound, which can reduce the generation of non-phase sound and avoid sound pressure attenuation.

[0045] By combining the low-power, high-decibel audible alarm circuit provided in Embodiment 1 with the structure of this audible alarm, the sound pressure level of the audible alarm is greatly improved while the power consumption is reduced. The maximum sound pressure output can reach 108dB (within a 1m range), and the maximum power consumption is only 7mA. When a fire occurs, the audible alarm can operate normally with a DC24V supply, greatly enhancing the alarm's warning effect.

[0046] The audible alarm device using the low-power, high-decibel audible alarm circuit of this embodiment has the characteristics of low power consumption, high sound pressure level, wide applicability, and minimal impact on the system. It meets the requirements of long-term heavy load and is less likely to affect other detection terminals.

[0047] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A low-power, high-decibel audible alarm circuit, characterized in that: The system includes a power supply circuit, a control circuit, and a sound output circuit. The power supply circuit supplies power to the control circuit, which in turn controls the sound pressure output of the sound output circuit. The sound output circuit includes a first MOSFET, a second MOSFET, a capacitor bank, and an inductor. The control circuit is connected to both the first and second MOSFETs. The first MOSFET is also connected to the capacitor bank, and the second MOSFET and the capacitor bank are each connected to an inductor. The inductor is also connected to a buzzer. The charging state of the capacitor bank is switched by controlling the first MOSFET to be on or off. When the second MOSFET is on, the inductor enters a charging state; when the second MOSFET is off, the inductor outputs a high voltage to the buzzer.

2. The low-power, high-decibel audible alarm circuit according to claim 1, characterized in that: The sound output circuit also includes a first transistor, which is connected to a first MOSFET and a control circuit. When the control circuit turns on the first transistor, the first MOSFET also turns on.

3. The low-power, high-decibel audible alarm circuit according to claim 2, characterized in that: The sound output circuit also includes a first rectifier, which is connected to a first MOS transistor.

4. The low-power, high-decibel audible alarm circuit according to any one of claims 1-3, characterized in that: The capacitor bank includes a first electrolytic capacitor and a second electrolytic capacitor, which are respectively connected to a first MOSFET.

5. The low-power, high-decibel audible alarm circuit according to claim 1, characterized in that: The power supply circuit includes a second rectifier, a second transistor, a third transistor, and a power supply chip; the second rectifier is connected to the second transistor and the third transistor respectively, the second transistor is also connected to the third transistor, and the third transistor is also connected to the power supply chip.

6. The low-power, high-decibel audible alarm circuit according to claim 5, characterized in that: The power supply circuit further includes a first resistor, a second resistor, and a Zener diode; one end of the second rectifier is connected to one end of the first resistor and one end of the second resistor, the other end of the first resistor is connected to the base of the second transistor and the cathode of the Zener diode, and the anode of the Zener diode is grounded; the other end of the second resistor is connected to the collector of the second transistor and the third transistor, the emitter of the second transistor is connected to the base of the third transistor, and the emitter of the third transistor is connected to the power supply chip.

7. The low-power, high-decibel audible alarm circuit according to claim 2, characterized in that: The control circuit includes an MCU chip, which includes a charging signal transmission terminal and an acoustic signal transmission terminal. The charging signal transmission terminal is connected to a first transistor, and the acoustic signal transmission terminal is connected to a second MOSFET.

8. The low-power, high-decibel audible alarm circuit according to any one of claims 1-3 and 5-7, characterized in that: The frequency range of the sweep output of the sound output circuit is 1.8K to 3.5K.

9. An audible alarm, characterized in that: The low-power, high-decibel audible alarm circuit includes any one of claims 1-8.

10. The audible alarm according to claim 9, characterized in that: It also includes a housing and a circuit board. A sound outlet is provided on one side of the housing, and the buzzer is located at the sound outlet. The circuit board is located inside the housing, and the low-power high-decibel sound alarm circuit is located on the circuit board and connected to the buzzer.

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