阅读说明：本技术 一种蜂鸣器控制电路及蜂鸣装置 (Buzzer control circuit and buzzer device ) 是由 黄伟群 韩邦强 延吉宝 王灏 吴俊文 彭爱军 张董华 秦雄华 吴世忠 朱洁乐 陈 于 2019-08-28 设计创作，主要内容包括：本发明公开了一种蜂鸣器控制电路及蜂鸣装置,包括：电机脉冲宽度调制器,用于将方波电压信号调整为脉冲宽度周期性变化的波形,所述波形在一个周期内脉冲宽度先由极小值变大到极大值,再由极大值变小到极小值；所述电机脉冲宽度调制器的输出端连接第一电阻；晶体管,所述晶体管的基极通过所述第一电阻连接所述电机脉冲宽度调制器,基极和发射极之间连接有并联的第二电阻和滤波电容,集电极连接有串联的第三电阻和第四电阻。本发明的蜂鸣器控制电路,能够在不提升成本的情况下,提升蜂鸣器的音质,使蜂鸣器能够发出令人愉乐的和弦音。(The invention discloses a buzzer control circuit and a buzzer device, comprising: the motor pulse width modulator is used for adjusting the square wave voltage signal into a waveform with periodically changed pulse width, and the pulse width of the waveform is firstly increased from a minimum value to a maximum value and then is decreased from the maximum value to the minimum value in one period; the output end of the motor pulse width modulator is connected with a first resistor; the base electrode of the transistor is connected with the motor pulse width modulator through the first resistor, a second resistor and a filter capacitor which are connected in parallel are connected between the base electrode and the emitting electrode, and the collector electrode of the transistor is connected with a third resistor and a fourth resistor which are connected in series. The buzzer control circuit can improve the tone quality of the buzzer under the condition of not improving the cost, so that the buzzer can emit pleasant chord tones.)

1. A buzzer control circuit, comprising:

the motor pulse width modulator is used for adjusting the square wave voltage signal into a waveform with periodically changed pulse width, wherein the width of a plurality of pulses of the waveform in one period is increased from a minimum value to a maximum value and then is decreased from the maximum value to the minimum value; the output end of the motor pulse width modulator is connected with a first resistor;

the base electrode of the transistor is connected with the motor pulse width modulator through the first resistor, the second resistor and the filtering module which are connected in parallel are connected between the base electrode and the emitting electrode, and the collector electrode of the transistor is connected with the third resistor and the fourth resistor which are connected in series.

2. A buzzer control circuit in accordance with claim 1,

the filtering module is a filtering capacitor.

3. A buzzer control circuit in accordance with claim 1,

the filtering module comprises a first capacitor and a second capacitor which are connected in parallel between the base electrode and the emitter electrode.

4. A buzzer control circuit in accordance with claim 1,

the filtering module comprises a filtering capacitor and a fifth resistor which are connected between the base electrode and the emitter electrode in series.

5. The buzzer control circuit of claim 1,

after being filtered by the filtering module, the input voltage of the transistor is a sine wave.

6. The buzzer control circuit of claim 5,

the transistor linearly amplifies an input sine wave.

7. A buzzer control circuit according to any one of claims 1-6, characterised in that it further comprises:

and the square wave power supply is used for generating a square wave voltage signal and inputting the square wave voltage signal to the motor pulse width modulator.

8. A buzzer control circuit in accordance with any one of claims 1-6,

the emitter of the transistor is grounded.

9. A buzzer unit comprising a buzzer and a buzzer control circuit, said buzzer control circuit being a buzzer control circuit according to any one of claims 1 to 8; the buzzer is bridged at two ends of the third resistor, the power supply end of the buzzer control circuit is connected with the power supply end of the buzzer, and the driving end of the buzzer control circuit is connected with the controlled end of the buzzer.

10. The buzzer unit of claim 9,

the controlled end input voltage of the buzzer is sine wave.

Technical Field

The invention belongs to the technical field of buzzers, and particularly relates to a buzzer control circuit and a buzzer device.

Background

The buzzer is an electronic buzzer with an integrated structure, adopts direct current voltage for power supply, and is widely applied to electronic products such as computers, printers, copiers, alarms, electronic toys, automobile electronic equipment, telephones, timers and the like as a sounding device. The buzzer has the biggest advantages of simple driving and low manufacturing cost. In a driving circuit of the common BUZZER, the BUZZER is output by the PWM of the singlechip, and the square wave is amplified through the switch, so that the BUZZER is driven to make a sound. However, the buzzer only emits harsh sounds, such as alarm sounds, and the like, with a single sound source.

A speaker, also called a "horn", is a very common electroacoustic transducer, different from a buzzer, and driven by a sine wave to emit various beautiful sounds. However, the speaker driving circuit is more complicated than the buzzer circuit, and a decoder, a memory scheme, a power amplifier circuit, and the like are required. Loudspeakers are therefore relatively expensive and are generally not suitable for sound sources for small appliances.

Disclosure of Invention

The purpose of the invention is realized by the following technical scheme.

The invention uses the motor pulse width modulator to adjust the input voltage signal of the square waveform into the waveform with periodically changed pulse width, and then the sine wave driving signal is obtained after the filtering by the capacitor, thereby leading the buzzer to emit soft chord sound.

In order to solve the above problem, a buzzer control circuit according to an embodiment of the first aspect of the present invention includes: the motor pulse width modulator is used for adjusting the square wave voltage signal into a waveform with periodically changed pulse width, and the pulse width of the waveform is firstly increased from a minimum value to a maximum value and then is decreased from the maximum value to the minimum value in one period; the output end of the motor pulse width modulator is connected with a first resistor; the base electrode of the transistor is connected with the motor pulse width modulator through the first resistor, a second resistor and a filter capacitor which are connected in parallel are connected between the base electrode and the emitting electrode, and the collector electrode of the transistor is connected with a third resistor and a fourth resistor which are connected in series.

The buzzer control circuit of the embodiment of the first aspect of the invention can improve the tone quality of the buzzer under the condition of not improving the cost, so that the buzzer can emit pleasant chord tones.

In some embodiments of the invention, further comprising: and the square wave power supply is used for generating a square wave voltage signal and inputting the square wave voltage signal to the motor pulse width modulator.

In some embodiments of the invention, the emitter of the transistor is grounded.

In some embodiments of the present invention, the filter module is a filter capacitor.

In some embodiments of the invention, the filtering module comprises a first capacitor and a second capacitor connected in parallel between the base and the emitter.

In some embodiments of the invention, the filter module comprises a filter capacitor and a fifth resistor connected in series between the base and the emitter.

In some embodiments of the present invention, the input voltage of the transistor is a sine wave after being filtered by the filtering module.

In some embodiments of the present invention, the transistor linearly amplifies an input sine wave. A buzzer device according to an embodiment of the second aspect of the present invention includes a buzzer and a buzzer control circuit, where the buzzer control circuit is the buzzer control circuit according to the embodiments of the first to third aspects of the present invention; the buzzer is bridged at two ends of the third resistor, the power supply end of the buzzer control circuit is connected with the power supply end of the buzzer, and the driving end of the buzzer control circuit is connected with the controlled end of the buzzer.

In some embodiments of the present invention, the controlled end input voltage of the buzzer is a sine wave.

The buzzer in the fourth aspect of the invention can improve the tone quality of the buzzer without increasing the cost, so that the buzzer can emit pleasant chord tones.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

figure 1 shows a schematic diagram of a buzzer control circuit in a first embodiment of the invention;

FIG. 2 is a waveform diagram of a voltage signal modulated by a motor pulse width modulator;

FIG. 3 illustrates a waveform of a voltage signal after capacitive filtering;

figure 4 shows a schematic diagram of a buzzer control circuit in a second embodiment of the invention;

figure 5 shows a schematic diagram of a buzzer control circuit in a third embodiment of the invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The principle of the invention is as follows: the invention uses the motor pulse width modulator to adjust the input voltage signal of the square waveform into the waveform with periodically changed pulse width, and then the sine wave driving signal is obtained after the filtering by the capacitor, thereby leading the buzzer to emit soft chord sound. Various implementation examples of the present invention are illustrated below by three examples.