KR102013068B1 - Ultra Directional Speaker Circuit With Enhanced Stability - Google Patents

Abstract

The present invention relates to a super-directional speaker circuit with increased stability. The disclosed super-directional speaker circuit with increased stability comprises: a first inductor and a third inductor connected to a positive electric signal line for a speaker input; a second inductor and a fourth inductor connected to a negative electric signal line for a speaker input; and a first speaker, a second speaker, a third speaker and a fourth speaker receiving the speaker inputs and converting the same into vibrations which people can perceive as sound. Audio signals having passed through the first inductor are input into positive terminals of the first and second speakers, respectively. Audio signals having passed through the second inductor are connected to negative terminals of the first and second speakers. Audio signals having passed through the third inductor are input into positive terminals of the third and fourth speakers, respectively. Audio signals passing through the fourth inductor are connected to negative terminals of the third and fourth speakers. According to the present invention, the super-directional speaker circuit with increased stability can prevent damage caused by back electromotive force of a super-directional speaker by controlling a voltage applied to a super-directional speaker within a predetermined range.

Description

Ultra Directional Speaker Circuit With Enhanced Stability

The present invention relates to a super directional speaker circuit with increased stability, and more particularly, to a super directional speaker circuit with increased stability capable of preventing breakage due to counter electromotive force.

The contents described in this section merely provide background information on the present embodiment and do not constitute a prior art.

Super-directional speaker is a speaker that can be heard only in a specific area by aiming and shooting the sound like a light, and the range of applications such as an exhibition hall, a bus station, and a guide system for the visually impaired are endless. Super-directional speaker is a special speaker that modulates a sound signal and delivers it on an ultrasonic signal. The sound transmission distance is up to 300m, far more than the normal speaker.

The CLASS D amplifier (Amp, Amplifier) of the general speaker and the superdirectional speaker according to the prior art typically converts the digital signal (DIGITAL SIGNAL) into an analog signal (ANALOG SIGNAL) using one LC FILTER.

Audi's amplifiers are divided into A, B, AB, and D classes according to the difference in how transistors or vacuum tubes amplify the waveform at the output stage of the amplifier. Class D amplifiers are either switching or pulse width modulation (PWM) amplifiers. Class-D amplifiers use PWM modulation technology, which typically transforms the input signal into a form that is good for communication. This approach allows switching devices to be fully on or off, greatly reducing power losses in the output devices, resulting in efficiencies of 90 to 95% (20% efficiency in class A), and audio signals drive the output devices. The PWM carrier signal is modulated to remove the high frequency PWM carrier frequency with a low pass filter (LPF) at the end.

The problem with the D-class amplifier circuit of the conventional super-directional speaker is that the capacitance (C) increases as the number of speakers connected to the signal line increases, and the coil width increases as the duty width increases according to the PWM duty when the PWM signal is applied. (COIL) There is a fatal problem that the voltage applied to the speaker exceeds the limit value (for example, 100Vp-p) due to the increase in back electromotive force and the speaker element is damaged due to damage.

Accordingly, the present invention is to propose a super-directional speaker circuit with increased stability that can solve the above technical constraints.

Korean Patent Registration No. 10-0622078, published on September 1, 2006 (name: Super-directional speaker system and signal processing method) Korean Registered Patent No. 10-1074431, released on October 11, 2011 (name: super directional ultrasonic speaker system) Korean Patent Registration No. 10-1833892, published on February 23, 2018 (Name: Piezoelectric MEMS-based super-directional loudspeaker and its beam steering method)

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-described problems of the prior art, and a main object of the present invention is to provide a superdirectional speaker circuit having increased stability that can prevent breakage caused by back electromotive force of a superdirectional speaker according to a conventional circuit configuration. have.

In addition, another object of the present invention is to provide a super-directional speaker circuit with increased stability that can control the voltage applied to the super-directional speaker within a certain range.

The problem to be solved of the present invention is not limited to those mentioned above, and another problem to be solved which is not mentioned will be clearly understood by those skilled in the art from the following description.

One aspect of the present invention for achieving the above object is a first inductor and a third inductor connected to an electrical signal line of a positive polarity for speaker input; A second inductor and a fourth inductor connected to an electrical signal line of negative polarity for speaker input; And a first speaker, a second speaker, a third speaker, and a fourth speaker for receiving the speaker input and converting the vibration into a vibration that can be perceived by a human. The audio signal passing through the first inductor is the first speaker. And an audio signal respectively input to the positive polarity terminal of the second speaker, and the audio signal passing through the second inductor is connected to the negative polarity terminal of the first speaker and the second speaker, and the audio signal passing through the third inductor is The stability is increased by being input to the positive polarity terminals of the third and fourth speakers, respectively, and the audio signal passing through the fourth inductor is connected to the negative polarity terminals of the third and fourth speakers. Provides a superdirectional speaker circuit.

The amplifiers of the first to fourth speakers may be class D amplifiers.

The audio signal input to the first to fourth speakers may be a pulse width modulation (PWM) signal.

According to the superdirectional speaker circuit having increased stability of the present invention, there is an effect that it is possible to provide a superdirectional speaker circuit with increased stability that can prevent breakage caused by counter electromotive force of the superdirectional speaker according to the conventional circuit configuration.

In addition, there is an effect that it is possible to provide a super-directional speaker circuit with increased stability that can control the voltage applied to the super-directional speaker within a certain range.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, included as part of the detailed description in order to provide a thorough understanding of the present invention, provide embodiments of the present invention and together with the description, describe the technical features of the present invention.
1 is a diagram of a configuration of a superdirectional speaker circuit according to the prior art.
2 is a diagram illustrating a configuration of a superdirectional speaker circuit having increased stability according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention.

Throughout the specification, when a part is said to "comprising" (or including) a component, this means that it may further include other components, except to exclude other components unless specifically stated otherwise. do. In addition, the terms “… unit”, “… unit”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. have. Also, "a or an", "one", "the", and the like are used differently in the context of describing the present invention (particularly in the context of the following claims). Unless otherwise indicated or clearly contradicted by context, it may be used in the sense including both the singular and the plural.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the embodiments of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the contents throughout the specification.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a diagram of a configuration of a superdirectional speaker circuit according to the prior art.

A CLASS D amplifier (Amp, Amplifier) of a superdirectional speaker according to the prior art typically converts a digital signal (DIGITAL SIGNAL) into an analog signal (ANALOG SIGNAL) using one LC FILTER.

1 illustrates a configuration in which six speakers are connected.

Capacitors pass high frequencies and suppress low frequencies according to capacitance (uF), while inductors pass low frequencies and suppress high frequencies according to capacitance (mF).

The circuit of FIG. 1 shows a low pass filter (LPF) using an LC element, and LPF is a basic type of all filters. LPF is implemented in the simplest form, and based on it, it is converted into various forms to create different kinds of filters.

  LPF is a filter structure used to filter out high frequency noise signals and to filter out only low frequency signals. It is a filter type that is widely used in all fields such as low frequency ripple in power supply stage, high frequency spurious removal, harmonic suppression and various detections.

Popular Class D amplifiers typically convert analog signals to PWM and then amplify them through a switching controller and an output stage instead of analog amplification devices such as transistors or tubes. The switched amplified digital signal is converted back into an analog signal through a low pass filter and input to the speaker.

PWM (Pulse Width Modulation) is a modulation scheme in which the duty cycle of a square wave is changed in accordance with another signal. Some synthesizers get chorus-like variations in this way. One way to pulse an analog signal (quasi-digitization) is to apply it to a power amplifier and simply get a large output.

The problem with the D-class amplifier circuit of the conventional super-directional speaker is that the capacitance (C) increases as the number of speakers connected to the signal line increases, and the coil width increases as the duty width increases according to the PWM duty when the PWM signal is applied. The (COIL) back electromotive force increases so that the voltage applied to the speaker exceeds a threshold value (eg, 100 Vp-p).

The counter electromotive force refers to an electromotive force generated in an opposite direction to a power supply voltage in an electric substrate or an electric circuit. When power is supplied from a power supply to a circuit with inductance, such as a transformer, a DC motor, or an alternating current motor, current flows rapidly at the moment the voltage is applied, so the electromotive force proportional to the magnitude of the change in current by Faraday's law of electromagnetic induction. This occurs in the opposite direction to the applied voltage.

If the duty width is widened according to the PWM duty, the speaker element is damaged due to back EMF in the D-class amplifier circuit of the super-directional speaker. There is no small product that can guarantee output while exceeding 100Vp-p among commercially available superdirectional speakers.

2 is a diagram illustrating a configuration of a superdirectional speaker circuit having increased stability according to an embodiment of the present invention.

In FIG. 2, a configuration in which six speakers are connected is illustrated, but the number of speakers is not limited thereto.

In FIG. 1 according to the prior art, the audio signal for the speaker input is connected in parallel to the positive polarities of the speakers T1 to T6 via the inductor L1 through the positive polarity electrical signal line (speaker cable), and through the electrical signal line with the negative polarity. The inductors L2 are connected in parallel to the negative polarities of the speakers T1 to T6, respectively.

On the other hand, in FIG. 2 according to the present invention, the inductor L1 and the inductor L2, the speaker T1 and the speaker T2 are grouped into one group, the inductor L3 and the inductor L4, the speaker T3 and the speaker T4 are grouped into two groups, the inductor L5 and the inductor L6, the speaker T5 and speaker T6 are grouped into three groups.

In an embodiment of the present invention, even if the number of speakers connected to the source is increased, the capacitance (C) is fixed to a constant value, so that the PWM signal is applied to each speaker even if the width of the PWM duty is wide. The voltage does not exceed a certain value (eg, 52Vp-p), making it safe from back EMF.

In group 1, the audio signal for speaker input is connected in parallel to the plus polarity of the speakers T1 to T2 via the inductor L1 through the electrical signal line (speaker cable) of positive polarity, and the inductor L2 is connected to the positive polarity of the electrical signal line with the negative polarity. Are connected in parallel to the negative polarity of the speakers T1 to T2, respectively.

In group 2, the audio signal for speaker input is connected in parallel through the inductor L3 via the positive polarity electrical signal line (speaker cable) to the plus polarity of the speakers T3 to T4, respectively, and the inductor L4 through the electrical signal line with the negative polarity. And connected in parallel to the negative polarity of the speakers T3 to T4, respectively.

In group 3, the audio signal for speaker input is connected in parallel through the inductor L5 via the positive polarity electrical signal line (speaker cable) to the plus polarity of the speakers T5 to T6, respectively, and the inductor L6 through the electrical signal line with the negative polarity. And connected in parallel to the negative polarity of the speakers T5 to T6, respectively.

Speakers T1 to T6 receive speaker inputs as electrical signals from source devices (such as microphones in performance halls and various audio players) and convert them into vibrations that can be perceived by humans as sounds.

The electrical signal line connecting the source device and the speaker devices T1 to T6 is manufactured to be able to transmit cleanly while minimizing a large amount of signal loss. There are various products depending on the material of wire, purity and cross-sectional area, binding method, insulation, shield, and terminal treatment. For example, the material of the wire of the speaker cable is copper, which has a very good electrical conductivity as well as heat, and copper is most widely used. In general, copper contains some oxygen, and oxygen is a component that interferes with current flow. Oxygen-free copper wire (OFC), which effectively removes and improves the quality of electrical transmission, is often used for speaker cables. Speaker wires can be used with a variety of wires, such as silver-plated oxygen-free copper wire, made entirely of silver, a mixture of silver-plated wire and copper wire, and tin.

On the other hand, the power amplifier serves to amplify the output sufficiently so that the speaker properly drives the output signal from the signal splitter. In the case of active speakers, the power amplifier is implemented in a form included in the speaker.

In FIG. 2, two groups are grouped into L1, L2, and T1 and T2, but the number of inductors and speakers that can be grouped into one group is not limited to two. It is possible to group three or more inductors and three or more speakers connected thereto in one group if it is possible to configure below the threshold at which the superdirectional speakers can be driven from back EMF. For example, the inductor L1, the inductor L2 and the inductor L3, the speaker T1, the speaker T2 and the speaker T3 are grouped into one group, the inductor L4, the inductor L5 and the inductor L6, the speaker T4, the speakers T5 and T6 are grouped into two groups, and the like.

The circuitry attached herein may be performed by computer program instructions. These computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment such that instructions executed through the processor of the computer or other programmable data processing equipment may not be included in each block or flowchart of the block diagram. It will create means for performing the functions described in each step. These computer program instructions may be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular manner, and thus the computer usable or computer readable memory. It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the functions described in each block or flowchart of each step of the block diagram. Computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operating steps may be performed on the computer or other programmable data processing equipment to create a computer-implemented process to create a computer or other programmable data. Instructions that perform processing equipment may also provide steps for performing the functions described in each block of the block diagram and in each step of the flowchart.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas falling within the scope of the present invention should be construed as being included in the scope of the present invention.

According to the superdirectional speaker circuit having increased stability of the present invention, a superdirectional speaker circuit having increased stability capable of preventing breakage due to back electromotive force of a superdirectional speaker by controlling a voltage applied to the superdirectional speaker within a predetermined range is provided. As it can be used as a solution provided, it is not only possible to use the related technology, but also the possibility of marketing or sales of the applied device as well as using the related technology is not only sufficient, but also realistically implemented. It is an invention that can be used.

L1, L2, L3, L4, L5, L6: Inductors
T1, T2, T3, T4, T5, T6: Speaker

Claims (3)

First and third inductors connected in parallel to electrical signal lines of positive polarity for speaker input;
A second inductor and a fourth inductor connected in parallel to an electrical signal line of negative polarity for speaker input; And
A first speaker, a second speaker, a third speaker, and a fourth speaker for receiving the speaker input and converting the vibration into a vibration that can be perceived by a human;
The audio signal passing through the first inductor is input to the positive polarity terminals of the first speaker and the second speaker, respectively, and the audio signal passing through the second inductor is connected to the negative polarity terminals of the first speaker and the second speaker. Connected,
The audio signal passing through the third inductor is input to the positive polarity terminals of the third speaker and the fourth speaker, respectively, and the audio signal passing through the fourth inductor is connected to the negative polarity terminals of the third speaker and the fourth speaker. Super-directional speaker circuit with increased stability, characterized in that connected. The method of claim 1,
The amplifier of the first to fourth speakers,
Super-directional speaker circuit with increased stability, characterized by a Class D amplifier. The method of claim 2,
The audio signal input to the first to fourth speakers is a super-directional speaker circuit, characterized in that the pulse width modulation (PWM) signal.

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