JP2010080995A - Method of driving onboard loudspeaker blowing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a driver surely recognize warning sound notifying a failure or the like of an onboard apparatus by generating large sound using a compact loudspeaker 2 mountable in an instrument panel 1 in a vehicle. <P>SOLUTION: A sound IC 17 outputs a sound signal of a predetermined blowing pattern. Thereby, a voltage of a high effective value supplying power not smaller than a rated value is applied to a coil 2a of the loudspeaker 2 in a first period T1 in an initial stage of blowing, and a low voltage is applied in the next second period T2. Alternatively, the voltage application in the second period T2 is stopped. The average power in one cycle (first period T1+second period T2) is set within a rated value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for driving a vehicle-mounted speaker sounding device having a speaker housed in a vehicle instrument panel.

  Conventionally, a large speaker is installed in a vehicle when an alarm sound for notifying a serious abnormality of an in-vehicle device is generated in the vehicle.

  Further, in the speaker protection circuit of Patent Document 1, when the output of the output amplifier exceeds the rating of the speaker, there is a circuit that uses a timer circuit to continue the over-rated state for a certain time or more. The speaker protection circuit then outputs a volume limit signal to prevent the speaker from being driven with power exceeding the rating.

  This Patent Document 1 discloses a mechanism for adjusting an output when the rated power of a speaker is exceeded. Patent Document 1 is a speaker protection means when an input signal is unspecified, and requires a mechanism for detecting whether or not the rated power is exceeded.

Next, an on-vehicle amplifier built-in speaker is known from Patent Document 2 in which a temperature detection element (detecting the temperature of a power IC and a frame) is provided in the structure of the speaker. The control of Patent Document 2 reduces or cuts off the output at a temperature at which there is a risk that the voice coil will melt.
JP 2005-286546 A JP 2001-28797 A

  However, the in-vehicle speaker requires a volume of about 85 dB. In this case, there is a problem that it becomes very large and requires a large mounting space. In view of such a problem, a driving method for an on-vehicle speaker blowing device having a large sound and a small physique is desired.

  However, those described in Patent Document 1 and Patent Document 2 are all for protecting the speaker, and do not provide an effective solution to the problem of downsizing the speaker.

  When the vehicle noise is louder than that of a passenger car, such as a truck or bus, the volume is required to be about 85 dB as described above in order to make the driver recognize the warning sound. In this case, if the mounting position of the speaker is within the instrument panel, for example, the speaker is required to have a rated power of about 1 W.

  This 1 W speaker is large in size and is not suitable for being built in an instrument panel. Furthermore, it becomes expensive.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for driving a speaker sounding device that can be built in an instrument panel of a vehicle, generates a sufficiently large sound, ensures that the driver is aware of the alarm, and uses a small and inexpensive speaker. The purpose is to provide.

  It is another object of the present invention to make it possible to use a speaker in a region where the rated power is exceeded without using a mechanism for detecting whether the rated power is exceeded when a blowing pattern is determined in advance.

  In the process of achieving this object, the inventor stated that “the speaker built in the instrument panel is different from a normal audio speaker, and it only sounds for a limited time in the vehicle life” and “85 dB. Focusing on the point that a high volume is required when a limited part of the alarm sound is played for a very short time among the variations of speaker blowing.

  In addition, attention was paid to the point that “normally required sound is about 65 dB, and thus a speaker having a rated power of 0.5 W can sufficiently generate sound of about 65 dB”.

  In addition, “In a normal speaker of about 0.5 W, when the power supplied is increased, the resistance value increases due to the heat generated by the coil. We also paid attention to the point that “if the coil exceeds the allowable temperature, there is concern about the deterioration of the life and characteristics of the speaker”.

  “In recognition of warning sound by the driver, if a loud sound is generated at the beginning of the warning sound, human beings have the ability to recognize the sound once conscious, even under low noise. I also focused on that.

  In order to achieve the above object, the present invention employs the following technical means. That is, according to the first aspect of the present invention, there is provided a driving method for an in-vehicle speaker sounding device mounted on an instrument panel (1) of a vehicle, and driving power is supplied to the speaker (2) and the speaker (2). Speaker driving means (10), and the speaker driving means (10) generates power equal to or higher than the rated power of the speaker (2) in a first period (T1) set in advance after the speaker (2) starts to blow. In the second period (T2) that is supplied to the speaker (2) and subsequently set in advance, the applied voltage to the speaker (2) is made lower than the applied voltage in the first period (T1), and the speaker (2) It is characterized in that the supplied power is reduced below the rated power.

  According to the first aspect of the present invention, when the speaker (2) starts to blow, since the power exceeding the rating is supplied, the speaker (2) can emit a large sound for its physique. . In addition, since the first period (T1) is set in advance, the speaker (2) is not damaged or the lifetime is not extremely shortened.

  Also, the driver's attention is drawn by the first loud sound, and a sufficient warning effect can be obtained with the small speaker (2). Furthermore, it can be mounted in the space of the instrument panel (1).

  Moreover, the electric power exceeding a rating is supplied for the time which a person can recognize at the beginning of blowing. Thereafter, before the temperature in the speaker (2) is heated and the temperature rises to the limit, the supplied power can be reduced within the rating.

  The sound once recognized by the driver can be easily heard down to a low volume even under noisy conditions. For this reason, the driver's consciousness can be concentrated on the alarm at the moment of the start of blowing by giving a loud sound at the beginning of blowing.

  Next, in the invention according to claim 2, the speaker driving means (10) makes the power supplied to the speaker (2) zero and makes the speaker (2) substantially silent in the second period (T2). It is characterized by that.

  According to the second aspect of the present invention, it has the second period (T2) after the first period in which power equal to or higher than the rated power is supplied to the speaker (2). The power supplied to the speaker is cut off during the second period (T2). Therefore, the speaker is not damaged or the lifetime is not extremely shortened. The first loud sound attracts the driver's attention, and a small speaker provides a sufficient warning effect. As a result, it can be installed in the space of the instrument panel of the vehicle.

  Next, in the invention described in claim 3, the speaker driving means (10) makes the power supplied to the speaker (2) in the second period (T2) less than the power supplied in the first period (T1). In the second period (T2), the speaker (2) is continuously blown with power within the rated power.

  According to the third aspect of the present invention, in the second period (T2), the alarm sound continues to sound following the first period (T1). Therefore, the driver's attention can be attracted to the alarm sound.

  Next, in the invention according to claim 4, the speaker driving means (10) applies the effective value of the trapezoidal driving voltage to the speaker (2) in the first period (T1), and then the second period. In (T2), the effective value of the sine wave drive voltage is applied.

  According to the fourth aspect of the present invention, the effective value of the trapezoidal driving voltage is applied in the first period (T1) during which the electric power exceeding the rating is supplied. This trapezoidal drive voltage includes harmonics in addition to the fundamental frequency. Therefore, the diaphragm of the speaker is vibrated by the harmonic. Therefore, a driving method of the on-vehicle speaker sounding device having a high alarm effect can be obtained. That is, by making the drive voltage a trapezoidal wave, in addition to the primary frequency component, sounds of harmonic components such as the third order and the fifth order are added. As a result, it becomes easier for the driver to notice the alarm sound. Therefore, it is possible to generate a sufficient alarm sound even when the speaker (2) having a small rated power is used.

  Next, in the invention described in claim 5, the speaker driving means (10) includes an audio signal generating circuit (17) for generating an audio signal and an amplifier for amplifying the audio signal from the audio signal generating circuit (17). (33), a modulator (35) for modulating the audio signal amplified by the amplifier (33) with an oscillation frequency higher than that of the audio signal, and a bridge circuit (37) for alternately passing a current to the speaker (2) The modulator (35) is composed of a PWM modulator (35).

  According to the fifth aspect of the present invention, the electric power supplied to the speaker (2) is controlled by changing the pulse width using the PWM modulator (35). Therefore, the speaker (2) can be blown by applying a voltage having a desired waveform to the speaker (2) with low loss switching.

  Next, in the invention described in claim 6, the audio signal generating circuit (17) for generating an audio signal is composed of an audio IC (17) in which an audio signal having a predetermined blowing pattern is stored. The on-vehicle speaker sounding device includes voice control calculation means (25) for controlling the voice IC (17), and the voice control calculation means (25) outputs a voice signal of the voice IC (17) at a desired timing. It is characterized by.

  According to the sixth aspect of the present invention, the audio signal is stored in the audio IC (17). Therefore, an audio signal having an arbitrary waveform or size stored in the audio IC (17) can be supplied to the speaker (2).

  Next, the invention according to claim 7 is characterized in that the sound signal has a trapezoidal sound signal portion in a portion corresponding to the first period (T1).

  According to the seventh aspect of the present invention, the audio signal has a trapezoidal wave portion. Therefore, it is possible to easily drive the speaker (2) with a trapezoidal driving voltage and generate an alarm sound having a harmonic component.

  Next, in the invention according to claim 8, the audio IC (17) stores therein a plurality of audio signals divided into multi-channels, and the audio control calculation means (25) is provided in the audio IC (17). One of the channels is designated, and an audio signal of the channel is output from the audio IC (17).

  According to the invention described in claim 8, multi-channel audio signals are stored in the audio IC (17). Therefore, an audio signal having an arbitrary waveform or size can be supplied to the speaker (2). As a result, alarm sounds with different tone colors and sound pressures and different alarm effects can be generated from the speaker (2) as necessary.

  In addition, the code | symbol in the parenthesis as described in a claim and said each means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5. FIG. 1 is a schematic diagram showing a state in which a speaker is built in the instrument panel 1. In FIG. 1, a speaker 2 is mounted on the rear side of a speedometer 3 displayed to the driver.

  The instrument panel 1 is provided with a fuel gauge 4, an alarm display device 5 for displaying various alarms, and a liquid crystal display device (LCD) 6.

  2 to 4 are external views of a single part of the speaker 2. The speaker 2 has a diaphragm 8 that vibrates due to electromagnetic force generated by a coil (not shown) inside the speaker 2. FIG. 3 is a side view of the speaker. The speaker 2 is provided with protruding pins 9 connected to a printed circuit board for supplying power. FIG. 4 is a rear view of the speaker 2.

  The diameter of the diaphragm 8 is 38 mm. The depth of the speaker 2 is about 9 mm excluding the pin 9. Such a speaker 2 can be sufficiently mounted on the back surface of the instrument panel 1 of FIG.

  The sound emission direction of the speaker 2 is the front of the vehicle. Therefore, sound is generated on the back surface of the instrument panel 1, and a sound is guided from a passage (not shown) on the back surface of the instrument panel 1 in the direction of the windshield. It can be recognized.

  FIG. 5 is a circuit configuration diagram of the first embodiment. In FIG. 5, driving power is supplied to the speaker 2 from a driving IC 10 constituting speaker driving means. The speaker driving IC 10 includes terminals 11 and 12 for supplying power (VDD). In addition, ground terminals 14 and 15 are provided in the lower part. A power supply capacitor 13 is connected to terminals 11 and 12 for supplying power (VDD).

  Further, the driving IC 10 is supplied with a control signal input terminal 16 to which a control signal for controlling the start and stop of the blowing of the speaker 2 is supplied, and a pulsating audio signal (0 to 5 V) from the audio IC (audio reproduction IC) 17. Are provided with audio input terminals 18a and 18b. The coupling capacitors 19 and 20 are connected to the audio input terminals 21 and 22.

  The audio IC 17 is a storage means for storing an audio signal, and the audio signal is stored therein in a multi-channel format. A voice control microcomputer 25 serving as voice control calculation means receives a signal from the system control device 26 in the vehicle.

  The voice control microcomputer 25 controls the voice IC 17 to supply the voice input terminal 18 with a voice signal of any channel stored in multiple channels in the voice IC 17.

  Note that the vehicle according to the first embodiment is a truck. This truck brakes with high pressure air. Therefore, it is dangerous if the pressure in the brake tank decreases. Therefore, in such a case, the speaker 2 generates a loud sound. Therefore, the system control device 26 inputs an alarm signal for lowering the brake tank internal pressure for the truck to the voice control microcomputer 25.

  The driving IC 10 includes an oscillator (OSC) 31 that starts oscillation in response to a signal from the (Bias) circuit 30 and a current amplifier 33 that includes an operational amplifier that amplifies the audio signal supplied from the audio signal input terminal 18.

  A signal from the audio IC 17 that has been amplified by the current amplifier 33 is modulated by a pulse width modulator (PWM) 35. For this purpose, an oscillation signal (clock input) from an oscillator (OSC) 31 oscillating at a high frequency much higher than that of an audio signal is input to the pulse width modulator 35.

  The pulse width modulator 35 has a pulse width duty cycle (ratio of high signal to low signal of pulse width) according to the magnitude of the signal (DC level) from the audio IC 17 amplified by the current amplifier 33. change. Thereby, power supply to the coil 2a of the speaker 2 serving as a load is controlled.

  The switching of the load current in the pulse width modulator 35 becomes switching control using the saturation (switching) region of the control transistor, and power can be supplied to the coil 2a in the speaker 2 with reduced power loss.

  The modulated signal is a signal composed of an infinite number of rectangular pulse trains (pulse widths are changing) with a constant peak value. This signal is applied as a bidirectional applied voltage (2 to 3 kHz) to the coil 2 a of the speaker 2 by an H-bridge circuit (H-Bridge) 37.

  The H bridge circuit 37 is an integrated circuit having a D-MOS output stage for driving a bidirectional load.

  FIG. 6 shows the effective value of the voltage applied to the coil 2 a of the speaker 2. This shape is a sine waveform with a high effective voltage value in the early stage of blowing. The sine wave referred to in the present invention may be a substantial sine wave, and some distortion is allowed.

  The first part of this waveform is the first period T1, and the time period after the effective value has decreased is the second period T2. The number of waves in the waveform in FIG. 6 is omitted in the middle as shown by the chain line.

  In the first period T1, since the current flowing through the coil 2a in FIG. 5 increases, a large alternating electromagnetic force acts on the diaphragm 8 of the speaker 2 in FIG. 2, and the diaphragm 8 vibrates with great displacement.

  The coil 2a starts to generate heat, but before the coil 2a melts or the resistance becomes too high, the output voltage of the driving IC 10 in FIG. 5 decreases as in the second period T2 in FIG. To do. Therefore, the sound is reduced, but the sound continues.

  Next, effects of the first embodiment will be described. The driver notices the warning sound by the loud sound of the first period T1, and attention is poured into the warning sound. Therefore, even if the sound is reduced as in the second period T2, the warning effect is not impaired.

  Thus, even a small speaker 2 having a small diameter can surely attract the driver's attention. Further, the speaker 2 can be stored in a small surplus space in the instrument panel 1 of FIG. 1, and the speaker 2 itself is also inexpensive.

  Next, the blowing pattern in the first embodiment will be described. The input of the speaker 2 in all the first periods T1 was 1 W (85 dB), and the initial blowing time (first period T1) was 1 second. In addition, the input of the speaker 2 in the second period T2 following the first period T1 is 0.5 W (65 dB), and the blowing time (second period T2) of this portion is 4 seconds.

  Therefore, the cycle is 5 seconds (1 second + 4 seconds), and the average input for 5 seconds is 0.6 W = (1 W × 1 + 0.5 W × 4) ÷ 5, and the rated power of the speaker 2 (continuous rated input) It became inside.

  In addition, the rated power said to this embodiment is a continuous rated input. Further, although one cycle is 5 seconds, it is possible to sound for 2 to 3 cycles instead of just one cycle.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following embodiments, the same components as those in the first embodiment described above are denoted by the same reference numerals, description thereof will be omitted, and different configurations and features will be described.

  The second embodiment is the same as the first embodiment except for the sound pattern only. In the blowing pattern in the second embodiment, the speaker input in the first period is 1 W (85 dB) and the blowing time (first period T1) is 2 seconds. Immediately after the first period T1, the silent period (second period T2) was 2 seconds, and the period (first period T1 + second period T2) was 4 seconds.

  The average power for 4 seconds was 0.5 W, which was within the rated power of the speaker 2. Such a cycle may be performed only once or may be repeated 2.3 times.

  Thus, in the second embodiment, there is a second period T2 in which there is a short blow exceeding the rated power for a short time and then the blow is stopped. Therefore, when sounding for a plurality of periods, intermittent sounding is repeated.

  Even in this case, the driver is attracted attention to the loud sound at the beginning of the blowing, and can fully recognize the warning sound even if the subsequent blowing stops or is intermittent. Further, since the period for stopping the blowing is always set for the second period T2, there is no occurrence of a failure such as damage to the coil 2a of the speaker 2 of FIG. 5 due to overcurrent.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a waveform of the effective value of the driving voltage applied to the coil 2a of the speaker 2 by the driving IC 10 (FIG. 5) in the third embodiment.

  In the third embodiment, as shown in FIG. 7, a trapezoidal driving voltage (effective value) is applied to the coil 2a of the speaker 2 in the first period T1 at the beginning of blowing. The number of waves in the waveform in FIG. 7 is omitted in the middle as shown by the chain line.

  The audio IC 17 in FIG. 5 is a storage means for storing audio signals and has multiple channels inside. A trapezoidal sound signal is stored in at least one of the channels for the first predetermined time. The voice control microcomputer 25 receives a signal from the system controller 26 of the brake system and controls the voice IC 17.

  When the brake system fails, an audio signal having a part of the trapezoidal wave is supplied to the audio input terminal 18.

  This DC level audio signal is amplified by a current amplifier 33 and further modulated by a pulse width modulator (PWM) 35. The modulated output voltage is applied to the coil 2a of the speaker 2 as an applied voltage from both directions by the H bridge circuit 37.

  FIG. 7 shows the effective value of the applied voltage, and this shape is a trapezoidal wave voltage waveform having a high effective value in the first period T1 in the early stage of blowing. Since this trapezoidal wave is a distorted wave, it includes third-order and fifth-order harmonic components in addition to the sine wave of the fundamental frequency (first-order frequency).

  That is, the trapezoidal wave is a composite wave of these various waveforms. Therefore, the diaphragm 8 (FIG. 2) of the speaker 2 is also excited by a harmonic having a frequency three to five times the fundamental frequency, and generates a high-frequency sound with a high alarm effect at the beginning of sounding.

  The first part of the waveform is the first period T1, and the time period after the effective value is reduced to become a sine wave is the second period T2.

  In the first period T1, since the current flowing through the coil 2a increases, a large alternating electromagnetic force acts on the diaphragm 8 in FIG. 2, and the diaphragm 8 is greatly displaced and vibrates. In addition, the coil 2a starts to generate heat, but before the coil 2a is melted or the resistance becomes too high, the voltage decreases as in the second period T2 in FIG. Therefore, the sound is reduced, but the sound continues.

  Next, the effect of this embodiment will be described. The driver is aware of the warning sound by the high sound with high warning effect in the first period, and attention is poured into the warning sound. Therefore, even if the sound is reduced as in the second period, the alarm effect is not impaired. Thereby, the same effect as the first embodiment can be obtained.

  The sound pattern in the third embodiment will be described. The input of the trapezoidal wave to the speaker 2 in the first period T1 was 1 W (85 dB), and the blowing time (first period) was 1 second. In addition, the input of the speaker 2 in the second period T2 continuous to the first period T1 was 0.5 W (65 dB), and the blowing time (second period) was 4 seconds. Therefore, the cycle was 5 seconds, and the average power for 5 seconds was 0.6 W, which was within the rated power of the speaker 2.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. The fourth embodiment is the same as the third embodiment except that only the blowing pattern is different from the third embodiment. In the blowing pattern in the fourth embodiment, the input by the trapezoidal wave of the speaker 2 in the first period T1 was 1 W (85 dB), and the blowing time (first period) was 2 seconds.

  After that, the substantially silent period of 2 seconds forms the second period T2, and one period is 4 seconds. The average power for 4 seconds was 0.5 W, which was within the rated power range of the speaker 2. And such a period may be made only once, and intermittent blowing may be performed by repeating 2.3 times.

  Thus, in the fourth embodiment, there is a short period of time (first period T1) including a harmonic sound exceeding the rated power. Then, the 2nd period T2 which stops blowing is set. Therefore, when sounding for a plurality of periods, it becomes intermittent sounding that repeats sounding.

  In this case as well, the driver is attracted attention to the loud sound at the beginning of the sound, and can fully recognize the alarm even if the subsequent sound stops or is intermittent. In addition, since the period for stopping the blowing is always set for the second period T2, no trouble such as burning of the coil 2a of the speaker 2 occurs.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows. In the second embodiment described above, the driving voltage having the trapezoidal wave for driving the speaker is generated by including the trapezoidal wave component in the audio signal itself in the audio IC.

  Instead, the peak value of the sine wave of the audio signal in the audio IC is partially made extremely high so that the current amplifier cannot amplify the sine wave part having the very high peak value (saturate it). A trapezoidal amplifier output may be generated.

  Further, a clip circuit that cuts the head of a high peak audio signal (sine wave) portion may be provided in front of the current amplifier to generate an audio signal having a trapezoidal wave portion.

  Further, the alarm content may be displayed on the liquid crystal display device 6 together with the generation of the alarm sound from the back of the instrument panel 1 by the speaker 2 of FIG. In this way, the sound generation direction and the display direction are the same as viewed from the driver. Therefore, the alarm content becomes easier to understand.

It is a front view of the instrument panel which shows typically the mounting state of the speaker in the vehicle-mounted speaker blowing apparatus used for 1st Embodiment of this invention. It is a front view which shows the external shape of the speaker used for the said 1st Embodiment. It is a side view of the speaker used for the said 1st Embodiment. It is a rear view of the speaker used for the said 1st Embodiment. It is an electric circuit diagram of the vehicle-mounted speaker blowing apparatus used for the said 1st Embodiment. It is a voltage waveform diagram which shows the waveform of the effective value of the voltage applied to a speaker in the said 1st Embodiment. It is a voltage waveform diagram which shows the waveform of the effective value of the voltage applied to the speaker of the vehicle-mounted speaker blowing apparatus used for 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Instrument panel 2 ... Speaker 2a ... Speaker coil 8 ... Diaphragm 10 ... Driving IC used as speaker driving means
17 ... Audio IC forming an audio signal generation circuit
25 ... Voice control microcomputer as voice control calculation means 26 ... System controller 31 ... Oscillator 33 ... Current amplifier 35 ... Pulse width modulator 37 ... H bridge forming bridge circuit T1 ... First period T2 ... Second period

Claims (8)

  A method for driving an on-vehicle speaker sounding device mounted on an instrument panel (1) of a vehicle, comprising: a speaker (2); and speaker driving means (10) for supplying driving power to the speaker (2), The speaker driving means (10) supplies power above the rated power of the speaker (2) to the speaker (2) in a first period (T1) set in advance after the speaker (2) starts to ring. In the subsequent second period (T2) set in advance, the voltage applied to the speaker (2) is made lower than the voltage applied in the first period (T1), and the power supplied to the speaker (2) is reduced. A method for driving an on-vehicle speaker sounding device, wherein the driving power is reduced below the rated power.   The said speaker drive means (10) makes the power supply to the said speaker (2) zero, and makes the said speaker (2) a substantially silent state in the 2nd period (T2). A driving method of the on-vehicle speaker sounding device according to claim 1.   The speaker driving means (10) reduces the power supplied to the speaker (2) in the second period (T2) to less than the power supplied in the first period (T1), and uses the power within the rated power. The driving method for the on-vehicle speaker sounding device according to claim 1, wherein the speaker (2) is continuously sounded in the second period (T2).   The speaker driving means (10) applies an effective value of a trapezoidal driving voltage to the speaker (2) in the first period (T1), and then drives a sine wave in the second period (T2). The driving method for the on-vehicle speaker sounding device according to claim 3, wherein an effective value of the voltage is applied.   The speaker driving means (10) includes an audio signal generation circuit (17) that generates an audio signal, an amplifier (33) that amplifies the audio signal from the audio signal generation circuit (17), and a frequency higher than that of the audio signal. The modulator (35) that modulates the audio signal amplified by the amplifier (33) with a high oscillation frequency, and a bridge circuit (37) that alternately supplies current to the speaker (2), the modulator ( 35. The driving method of the on-vehicle speaker sounding device according to any one of claims 1 to 4, characterized in that 35) comprises a PWM modulator (35).   The sound signal generation circuit (17) for generating the sound signal is composed of a sound IC (17) in which a sound signal having a predetermined sound pattern is stored therein, and the in-vehicle speaker sounding device is the sound IC. 6. A voice control calculation means (25) for controlling (17), wherein the voice control calculation means (25) outputs the voice signal of the voice IC (17) at a desired timing. The driving method of the on-vehicle speaker sounding device described in 1.   The driving method of the on-vehicle speaker sounding device according to claim 5 or 6, wherein the audio signal has a trapezoidal wave audio signal portion in a portion corresponding to the first period (T1).   The audio IC (17) stores therein a plurality of audio signals divided into multiple channels, and the audio control arithmetic means (25) assigns one channel in the multi-channel to the audio IC (17). The driving method of the on-vehicle speaker sounding device according to claim 6, wherein the audio signal of the channel is designated and output from the audio IC (17).

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