JPH0922289A - Driving method and driving device for sounding body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving method and a driving device for sounding body capable of simplifying the device by performing the volume control of a sounding body with the pulse width of a pulse signal and performing the musical interval control of the sounding body with frequency. SOLUTION: This device is provided with a sounding body 101 generating a sound by impressing an AC voltage on a coil fixed in a magnetic circuit and by vibrating a resonance plate, a pulse width modulation signal generating means 102 capable of changing the pulse width of an output pulse signal pwm and a designation means designating the output pulse width of the pulse width modulation signal generating means 102. Then, the volume of the sounding body is changed by changing the pulse width of the output pulse signal pwm of the pulse width modulation signal generating means based on the designation by the designation means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method and a driving apparatus for a so-called wound-type sounding body or a magnetic sounding body, and more particularly to a pulse width modulation (PWM).
Ion) is used to control the volume and pitch of the sounding body, and to a sounding body driving method and driving device.

[0002]

2. Description of the Related Art Conventionally, as a driving method and a driving device for a sounding body called a wire-wound sounding body or a magnetic sounding body, a method of driving by a pulse signal is generally used. The volume of the sound generator was controlled, and the pitch of the sounding body was controlled by the frequency of the pulse signal.

[0003]

However, in the above-mentioned conventional method and driving apparatus for a sounding body by controlling the amplitude of the pulse signal, the amplitude control may be separately performed in addition to the pulse signal generating means depending on the configuration of the driving apparatus. A variable gain amplifier or the like for performing the above is required, and a certain amount of hardware is required, which is an obstacle to downsizing the device.

The present invention has been made in view of the above-mentioned conventional problems, and uses pulse width modulation to control the volume of the sounding body by the pulse width of the pulse signal and the sounding body at the frequency of the pulse signal. It is an object of the present invention to provide a sounding body driving method and a driving device that can simplify the driving device by individually performing the pitch control.

[0005]

In order to solve the above-mentioned problems, a method of driving a sounding body according to claim 1 of the present invention comprises applying a AC voltage to a coil fixed to a magnetic circuit to form a resonance plate. In a method of driving a sounding body that generates a sound by vibrating, the volume is changed by changing the pulse width of a pulse signal supplied to the sounding body, and the pitch is changed by changing the frequency of the pulse signal. .

The drive unit for a sounding body according to a second aspect of the invention is a drive unit for a sounding body that generates a sound by applying an AC voltage to a coil fixed to a magnetic circuit to vibrate a resonance plate, The pulse width modulation signal generation means capable of changing the pulse width of the output pulse signal and the designating means for designating the output pulse width of the pulse width modulation signal generation means are provided, and the pulse width modulation based on the designation of the designating means. By changing the pulse width of the output pulse signal of the signal generating means,
The volume of the sounding body is changed.

According to a third aspect of the present invention, in the sounding body driving apparatus according to the second aspect, the designating means designates the frequency of the output pulse signal of the pulse width modulation signal generating means. The pitch of the sounding body is changed by changing the frequency of the output pulse signal of the pulse width modulation signal generating means based on the specification of the specifying means.

[0008]

In the method of driving a sounding body according to claim 1 of the present invention, a so-called wound-type sounding body which produces a sound by vibrating a resonance plate by applying an AC voltage to a coil fixed to a magnetic circuit. Alternatively, as a method of driving a sounding body called a magnetic sounding body, the volume is controlled by changing the pulse width of the pulse signal supplied to the sounding body, and the pitch is controlled by changing the frequency of the pulse signal.

Unlike the conventional amplitude control which is controlled by an analog amount, since the volume can be set programmable by digital pulse width control, that is, time control, the control is simple and the driving device can be simplified. In particular, if a microcomputer provided with a pulse width modulation (PWM) mode is used, it becomes possible to directly control the output of the microcomputer and the size of the device can be reduced.

Further, in the sounding body driving apparatus according to the second aspect, the pulse width of the output pulse signal is set based on the designation of the designating means as a driving apparatus for a so-called wound type sounding body or a magnetic sounding body. The pulse width of the output pulse signal of the variable pulse width modulation signal generating means is changed to change the volume of the sounding body.

As described above, since the volume can be set programmable by digital pulse width control, that is, time control, the control is simple and the driving device can be simplified.
In particular, if a microcomputer provided with a pulse width modulation (PWM) mode is used, it becomes possible to directly control the output of the microcomputer and the size of the device can be reduced.

In the sounding body driving apparatus according to the third aspect, the frequency of the output pulse signal of the pulse width modulation signal generating means is designated by the designating means, and the pulse width modulation is designated based on the designation of the designating means. It is desirable to change the frequency of the output pulse signal of the signal generating means to change the pitch of the sounding body.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sounding body driving method and a sounding body driving apparatus of the present invention will be described in detail below with reference to the drawings. FIG. 1A is a block diagram of a sounding body driving apparatus according to an embodiment of the present invention.

In FIG. 1, the sounding body driving apparatus according to the present embodiment has a sounding body 101 which produces a sound by applying an AC voltage to a coil fixed to a magnetic circuit to vibrate a resonance plate, and an output. PWM generator (pulse width modulation signal generation means) capable of changing the pulse width of the pulse signal pwm
102, and an amplification section for current-amplifying the pulse signal pwm.

As an example of the sounding body 101, FIG. 2 shows a sectional structural view of a small magnetic sounding body "CB-09AP". In the figure, 201 is a case, 202 is a base, 20
3 is a resonance plate, 204 is a magnetic piece, 205 is an iron core, 206 is a magnet, 207 is a bobbin, 208 is a bottle, 209 is a coil, 210 is a printed circuit board, 211 is a potting agent, and 212 is a liquid-proof label.

The sounding body 101 has a structure similar to a general dynamic speaker, and has a structure which resonates around a specific frequency. Permanent magnet (magnetic piece 204) and iron core 205
A coil 209 is fixed to a magnetic circuit consisting of a metal diaphragm having a high magnetic permeability through a narrow gap (resonance plate 203).
Is provided. This resonance plate 203 is previously attracted to and supported by the iron core 205 because of the DC magnetic field generated by the magnetic piece 204. When an AC signal is applied to the coil 209, an AC magnetic flux due to the AC signal is superposed, and the attraction force becomes an AC signal. Since the frequency changes according to the frequency, the resonance plate 203 vibrates and a sound is generated.

Further, in the present embodiment, the PWM generator 1
As 02, a microcomputer having a pulse width modulation (PWM) mode, for example, "H8 / 3048" manufactured by Hitachi, Ltd. is used. This microcomputer is capable of selecting the counter clock and the counter clear factor. By setting the 1/0 output timing of the output signal waveform in the register and setting it in the PWM mode, a pulse signal with a predetermined pulse width modulation is generated. It is what is output. Therefore, this microcomputer
The WM generator 102 also has a function of specifying means for specifying the pulse width of the output pulse signal pwm.

Further, the driving unit is constituted by resistors 103 and 104, a transistor 105, and a diode 106, current-amplifies the pulse width-modulated pulse signal pwm, and supplies it to the small magnet sounding body 101. .

FIG. 1B shows a PWM generator 10
2 shows a signal waveform of the output pulse signal pwm of FIG. The pulse width Ton is also designated by the designating means with respect to the cycle T determined by the frequency designated by the designating means. That is, in the above microcomputer, the cycle T is determined by the selection of the counter clock and the counter clear factor, and the pulse width Ton is determined by yt as the content of the register that sets the 1/0 output timing of the output signal waveform.

The relationship between the period T and the pulse width Ton is represented by the duty ratio defined by the following equation. Duty ratio = Ton / (T / 2) [%]

FIG. 3 shows a characteristic curve of sound volume [dBSPL] -duty ratio [%] in the sounding body driving apparatus of this embodiment. The sound generator 101 is the above-mentioned small magnetic sound generator "CB-09AP" (resonance frequency f0 = 2.
92 [kHz]), the PWM generator 102 is a microcomputer “H8 / 3048”, the resistance value R1 of the resistor 103 is 1.5 [kΩ], and the resistance value R2 of the resistor 104 is 4
7 [kΩ], and the transistor 105 is set to “2SC418
1 ”and the measured value when the diode 106 is“ MA112 ”.

As can be seen from the characteristic curve of FIG. 3, the volume-
The duty ratio characteristic is already saturated in the vicinity of the duty ratio of 50 [%]. Therefore, the actual change of the duty ratio is sufficient in the range of 0 to 40 [%], and as a result, the consumption is less. There is also an effect that the volume of the sounding body can be controlled by electric power.

The PWM generator 102 is not limited to a microcomputer having a pulse width modulation (PWM) mode, but may be an operational amplifier as shown in FIG. In the concrete example shown in FIG. 4, a triangular wave is generated by the operational amplifiers 401 and 402, and the triangular wave is compared by the operational amplifier 403 (comparator) with a potential determined by the value of the power supply VCC and the variable resistor 407 to generate a pulse. This is a configuration for generating the signal pwm. still,
The pulse width is set by changing the value of the variable resistor 407 and controlling the potential applied to the (+) terminal of the operational amplifier 403.

Further, as the PWM generator 102,
A well-known frequency divider configuration is also conceivable. When the PWM generator 102 is configured by the configuration of the operational amplifier and the configuration of the frequency divider, the designating unit may be configured by using a general microcomputer, for example. That is, the configuration of the operational amplifier digitally controls the value of the variable resistor 407, and the configuration of the frequency divider digitally controls the division ratio.

As described above, according to the sounding body driving apparatus of this embodiment, the volume of the sounding body 101 is changed by changing the pulse width of the output pulse signal pwm of the PWM generator 102 based on the designation of the designating means. Output pulse signal pw
Since the pitch of the sounding body 101 is changed by changing the frequency of m, it is possible to programmatically set the volume and the pitch by digital pulse width control, that is, time control, which simplifies the control and simplifies the driving device. it can. In particular, if a microcomputer equipped with a pulse width modulation (PWM) mode is used, it becomes possible to directly control the output of the microcomputer, and it is possible to further improve the drive device without constructing a new pulse width modulation signal generating means. The size can be reduced.

[0026]

As described above, according to the first aspect of the present invention,
According to the method of driving a sounding body according to the above, as a method of driving a sounding body called a so-called wound-type sounding body or a magnetic sounding body, volume control is performed by changing the pulse width of a pulse signal supplied to the sounding body, Since the pitch is controlled by changing the frequency of the signal, the sound volume can be set programmably by digital pulse width control, that is, time control, so that the control is simplified and a sounding body driving method that can simplify the driving device is provided. In particular, if a microcomputer equipped with a pulse width modulation (PWM) mode is used, it becomes possible to directly control by the output of the microcomputer, and a driver for a sounding body that can be downsized can be realized. can do.

Further, according to the sounding body driving apparatus of the second aspect, a pulse of the output pulse signal is output based on the designation of the designating means as a sounding body driving apparatus called a so-called wound type sounding body or a magnetic sounding body. Since the pulse width of the output pulse signal of the pulse width modulation signal generating means capable of changing the width is changed to change the volume of the sounding body, the volume is set programmable by digital pulse width control, that is, time control. Therefore, the control can be simplified and the drive device can be simplified. In particular, if a microcomputer having a pulse width modulation (PWM) mode is used, the output of the microcomputer can be directly controlled, and the device can be downsized. It is possible to provide a driving device for a sounding body capable of achieving the above.

According to the sounding body driving apparatus of the third aspect, the frequency of the output pulse signal of the pulse width modulation signal generating means is designated by the designating means, and the pulse is generated based on the designation of the designating means. Since the frequency of the output pulse signal of the width modulation signal generating means is changed to change the pitch of the sounding body, the sound volume of the sounding body is controlled by the pulse width of the pulse signal, and the pitch of the sounding body is changed by the frequency of the pulse signal. It is possible to provide a driving device for a sounding body, which can be controlled respectively to simplify the driving device.

[Brief description of drawings]

1A is a configuration diagram of a sounding body driving apparatus according to an embodiment of the present invention, and FIG. 1B is a signal waveform diagram of an output pulse signal of a PWM generator.

FIG. 2 is a cross-sectional structure diagram of a small magnetic speaker.

FIG. 3 is a characteristic diagram of volume-duty ratio in the sounding body driving apparatus of the embodiment.

FIG. 4 is a circuit diagram of another specific example of the pulse width modulation signal generation means.

[Explanation of symbols]

 101 sound generator 102 PWM generator 103, 104 resistance 105 transistor 106 diode VCC power supply (potential) GND ground (potential) 201 case 202 base 203 resonance plate 204 magnetic piece 205 iron core 206 magnet 207 bobbin 208 bin 209 coil 210 printed board 211 potting Agent 212 Liquid-proof label 401, 402, 403 Operational amplifier 404-406, 408-413 Resistor 407 Variable resistor 414, 415 Capacitor

Claims (3)

[Claims] 1. A method of driving a sounding body which generates a sound by applying an alternating voltage to a coil fixed to a magnetic circuit to vibrate a resonance plate, wherein a pulse width of a pulse signal supplied to the sounding body. Changes the volume,
A method of driving a sounding body, characterized in that a pitch is changed by changing a frequency of the pulse signal. 2. A pulse width capable of changing a pulse width of an output pulse signal in a sounding body driving apparatus which generates a sound by applying an AC voltage to a coil fixed to a magnetic circuit to vibrate a resonance plate. Modulation signal generating means and designating means for designating an output pulse width of the pulse width modulation signal generating means, and the pulse width of the output pulse signal of the pulse width modulation signal generating means based on the designation of the designating means. A drive device for a sounding body, characterized in that the sound volume of the sounding body is changed by the change. 3. The designating means designates the frequency of the output pulse signal of the pulse width modulation signal generating means, and changes the frequency of the output pulse signal of the pulse width modulation signal generating means based on the designation of the designating means. 3. The sounding body driving apparatus according to claim 2, wherein the pitch of the sounding body is changed.