Buzzer voltage doubler driving circuit and electronic device

Abstract

The application discloses a buzzer voltage-doubler driving circuit and electronic equipment, the buzzer voltage-doubler driving circuit includes: a buzzer module for sounding; a voltage-doubler module including a first switch unit, a second switch unit and a charging unit, the charging unit is connected with a power supply, the first switch unit is connected with the charging unit, and the second switch unit is connected with the power supply, the charging unit and the buzzer module; wherein, the first switch unit is controlled by a pulse signal source to be on or off, when the first switch unit is turned on, the charging unit is charged by the power supply to generate multiple voltage of the power supply, and the multiple voltage of the power supply controls the second switch unit to be turned on to drive the buzzer module to sound.The buzzer voltage-doubler driving circuit of the application drives the buzzer module to sound by generating multiple voltage of the power supply, the buzzer module has large volume and good tone when sounding, and the buzzer module can normally sound under the condition of low voltage of the power supply, meeting the working requirements.

Description

Technical Field

[0001] This invention relates to the field of buzzer drive circuit technology, and in particular to a buzzer voltage multiplier drive circuit and electronic device. Background Technology

[0002] A buzzer is a common acoustic device that generates sound through electromagnetic or piezoelectric effects. Buzzers are widely used in alarm, prompt, and notification scenarios. However, when used in battery-powered devices, buzzers may malfunction under low voltage conditions. For example, buzzers in remote monitoring systems or some portable devices may not function properly when the battery is low-powered after prolonged use, even if it's not completely depleted. In such cases, the internal drive circuit may fail to activate the buzzer, or even remain unresponsive. The buzzer's operation is limited by low voltage conditions, preventing the device from functioning effectively under these conditions. Summary of the Invention

[0003] This invention provides a buzzer voltage doubler drive circuit and electronic device to solve the problem that the buzzer cannot produce sound normally under low power supply conditions.

[0004] In a first aspect, embodiments of the present invention provide a buzzer voltage doubler drive circuit, comprising:

[0005] Buzzer module, used to produce sound;

[0006] A voltage multiplier module includes a first switching unit, a second switching unit, and a charging unit. The charging unit is connected to a power source. The first switching unit is connected to the charging unit. The second switching unit is connected to the power source, the charging unit, and the buzzer module.

[0007] The first switching unit is controlled to turn on and off by a pulse signal source. When the first switching unit is turned on, the charging unit is charged by the power supply to generate a multiple voltage of the power supply. The multiple voltage of the power supply controls the second switching unit to turn on and drive the buzzer module to sound.

[0008] In the buzzer voltage multiplier drive circuit provided in the embodiment of the present invention, the charging unit includes a bootstrap capacitor and a pull-up resistor. The bootstrap capacitor has a first end and a second end. The first end of the bootstrap capacitor is connected to the first switching unit and one end of the pull-up resistor. The second end of the bootstrap capacitor is connected to the second switching unit and the power supply. The other end of the pull-up resistor is connected to the power supply. The first switching unit is turned on to ground the first end of the bootstrap capacitor.

[0009] In the buzzer voltage multiplier drive circuit provided in the embodiment of the present invention, the charging unit further includes a first diode, the cathode of the first diode is connected to the second terminal of the bootstrap capacitor and the second switching unit, and the anode of the first diode is connected to the power supply.

[0010] In the buzzer voltage multiplier drive circuit provided in the embodiment of the present invention, the first switching unit includes a first switching transistor. The first switching transistor has an input terminal, an output terminal and a control terminal. The control terminal of the first switching transistor is connected to the pulse signal source. The input terminal of the first switching transistor is connected to the first terminal of the bootstrap capacitor. The output terminal of the first switching transistor is grounded.

[0011] In the buzzer voltage multiplier drive circuit provided in this embodiment of the invention, the first switching unit further includes a first current-limiting resistor, the first switching transistor is an NPN transistor, the input terminal of the first switching transistor is the collector of the NPN transistor, the output terminal is the emitter of the NPN transistor, the control terminal is the base of the NPN transistor, one end of the first current-limiting resistor is connected to the base of the NPN transistor, and the other end is connected to the pulse signal source.

[0012] In the buzzer voltage multiplier drive circuit provided in this embodiment of the invention, the second switching unit includes a second switching transistor. The second switching transistor has an input terminal, an output terminal, and a control terminal. The control terminal of the second switching transistor is connected to the anode of the first diode and the power supply. The input terminal is connected to the second terminal of the bootstrap capacitor and the cathode of the first diode. The output terminal is connected to the buzzer module. The voltage at the input terminal of the second switching transistor is greater than the voltage at the control terminal, which causes the second switching transistor to conduct.

[0013] In the buzzer voltage multiplier drive circuit provided in this embodiment of the invention, the second switching unit further includes a second current-limiting resistor. The second switching transistor is a PNP transistor. The input terminal of the second switching transistor is the emitter of the PNP transistor, the output terminal is the collector of the PNP transistor, and the control terminal is the base of the PNP transistor. One end of the second current-limiting resistor is connected to the base of the PNP transistor, and the other end is connected to the power supply and the anode of the first diode.

[0014] In the buzzer voltage multiplier drive circuit provided in the embodiment of the present invention, the voltage multiplier module further includes a discharge unit. The buzzer module is provided with a first input terminal and a second input terminal. The first input terminal is connected to the output terminal of the second switching transistor, and the second input terminal is grounded. The discharge unit is connected to the first input terminal and the second input terminal. The discharge unit is used to discharge the bootstrap capacitor.

[0015] In the buzzer voltage multiplier drive circuit provided in the embodiment of the present invention, the discharge unit includes a first resistor, one end of the first resistor is connected to the first input terminal, and the other end of the first resistor is connected to the second input terminal.

[0016] Secondly, embodiments of the present invention provide an electronic device, the electronic device including the buzzer voltage doubler drive circuit described in the first aspect.

[0017] This invention provides a buzzer voltage multiplier drive circuit and electronic device. The buzzer voltage multiplier drive circuit includes: a buzzer module for sound generation; and a voltage multiplier module including a first switching unit, a second switching unit, and a charging unit. The charging unit is connected to a power supply. The first switching unit is connected to the charging unit, and the second switching unit is connected to the power supply, the charging unit, and the buzzer module. The first switching unit is controlled by a pulse signal source. When the first switching unit is on, the charging unit is charged by the power supply to generate a voltage multiple of the power supply. The voltage multiple of the power supply controls the second switching unit to turn on, driving the buzzer module to generate sound. This buzzer voltage multiplier drive circuit generates a voltage multiple of the power supply by turning on the first switching unit to charge the charging unit. The voltage multiple of the power supply then drives the second switching unit to turn on, driving the buzzer module to generate sound. This results in a loud and high-quality buzzer module that can still operate normally even under low voltage conditions, meeting operational requirements. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a structural block diagram of a buzzer voltage multiplier drive circuit provided in an embodiment of the present invention;

[0020] Figure 2 A circuit diagram of a buzzer voltage multiplier drive circuit provided in an embodiment of the present invention;

[0021] The labels for the attached figures are as follows:

[0022] 10. Buzzer module; 20. Power supply; 21. Pulse signal source; 30. Voltage multiplier module; 31. First switching unit; 32. Second switching unit; 33. Charging unit; 34. Discharging unit. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0027] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0028] To facilitate understanding of the present invention, the buzzer voltage doubler drive circuit provided in the embodiments of the present invention will be described first. (Refer to...) Figure 1 and Figure 2This invention provides a buzzer voltage multiplier driving circuit, comprising: a buzzer module 10 for sound generation; and a voltage multiplier module 30, including a first switching unit 31, a second switching unit 32, and a charging unit 33. The charging unit 33 is connected to a power supply 20, the first switching unit 31 is connected to the charging unit 33, and the second switching unit 32 is connected to the power supply 20, the charging unit 33, and the buzzer module 10. The first switching unit 31 is controlled to switch on and off by a pulse signal source 21. When the first switching unit 31 is on, the charging unit 33 is charged by the power supply 20 to generate a voltage multiple of the power supply 20. The voltage multiple of the power supply 20 controls the second switching unit 32 to turn on, driving the buzzer module 10 to generate sound.

[0029] In practice, traditional buzzer driver circuits often use transistor circuits to drive the buzzer to produce sound. After the driving transistor is turned on, the voltage provided by the power supply is directly input to the buzzer to drive it to produce sound. When the power supply is under low voltage conditions, the voltage provided by the power supply cannot maintain the normal operation of the buzzer, making the buzzer sound soft and intermittent, or even silent.

[0030] Therefore, this embodiment provides a buzzer voltage multiplier drive circuit, which uses the charging unit 33 to charge the power supply 20 to generate a multiple voltage of the power supply 20, and drives the buzzer module 10 to emit sound through the multiple voltage of the power supply 20. The buzzer module 10 can also emit sound normally under the condition of low voltage of the power supply 20.

[0031] The buzzer voltage multiplier drive circuit of this embodiment can be applied to various electronic devices, mainly battery-powered electronic devices, such as smoke detectors and metal detectors. This embodiment's buzzer voltage multiplier drive circuit includes a buzzer module 10 and a voltage multiplier module 30. The buzzer module 10 is mainly used for sound generation. The principle of sound generation by the buzzer module 10 is to produce sound through electromagnetic or piezoelectric effects. The buzzer module 10 in this embodiment is an active buzzer module 10, meaning that the buzzer module 10 has a built-in oscillation source. It only needs a driving voltage applied to its input terminal to produce sound. The voltage multiplier module 30 includes a first switching unit 31, a second switching unit 32, and a charging unit 33. The charging unit 33 is connected to the power supply 20, the first switching unit 31 is connected to the charging unit 33, and the second switching unit 32 is connected to the power supply 20, the charging unit 33, and the buzzer module 10. Specifically, the first switching unit 31 is a unit composed of switching devices, such as switching transistors (MOSFETs, triodes), relays, optocouplers, etc. In practical circuit applications, the pulse signal source 21 is connected to the power supply 20, and the first switching unit 31 is connected to the pulse signal source 21. The first switching unit 31 is controlled to turn on and off by the pulse signal source 21. The pulse signal source 21 controls the on and off of the first switching unit 31 by emitting high and low level signal pulses. The pulse signal source 21 can be a microprocessor, oscillator circuit, or other structure that can emit high and low level signal pulses. Whether the buzzer module 10 needs to emit sound is mainly determined by the level signal output by the pulse signal source 21. When the pulse signal source 21 emits a pulse signal to control the first switching unit 31 to turn on, the charging unit 33 is charged by the power supply 20, that is, the first switching unit 31 acts as the charging switch for the charging unit 33. The charging unit 33 is designed with capacitors and other components. Utilizing the principle that capacitor voltage cannot change abruptly, the charging unit 33 generates a voltage multiple of the power supply 20 after charging. The multiple voltage of the power supply 20 is a number of times the voltage of the power supply 20. Specifically, it is designed to be an integer multiple. For example, if the voltage of the power supply 20 is 3.3V, taking a voltage twice that of the power supply 20 as an example, the multiple voltage of the power supply 20 generated by the charging unit 33 after charging can be 6.6V. The second switching unit 32 is connected to the power supply 20, the charging unit 33, and the buzzer module 10. It acts as a switch between the charging unit 33 and the buzzer module 10. The on / off state of the second switching unit 32 is mainly controlled by the voltage on the charging unit 33. The second switching unit 32 is turned on by a multiple of the voltage of the power supply 20 generated on the charging unit 33. Specifically, the condition for the second switching unit 32 to turn on is that the voltage on the charging unit 33 is greater than the voltage of the power supply 20. When the voltage on the charging unit 33 is less than or equal to the voltage of the power supply 20, the second switching unit 32 is in the off state. A multiple of the voltage of the power supply 20 can turn the second switching unit 32 on.After the second switching unit 32 is turned on, the multiple voltage of the power supply 20 is input to the input terminal of the buzzer module 10 through the second switching unit 32, driving the buzzer module 10 to produce sound. The multiple voltage of the power supply 20 is used as the driving voltage of the buzzer module 10 to drive the buzzer module 10 to work. When the power supply 20 voltage is sufficient, the multiple voltage of the power supply 20 can enhance the vibration amplitude of the buzzer module 10, making the volume louder and the sound quality better when the buzzer module 10 produces sound. When the power supply 20 voltage is low, within a certain range below the minimum driving voltage of the buzzer module 10, the multiple voltage of the power supply 20 can still meet the minimum driving voltage requirement of the buzzer module 10 to the greatest extent, so that the buzzer module 10 can produce sound normally. For example, the minimum driving voltage requirement for buzzer module 10 is 1.5V. When the voltage of power supply 20 is 0.8V, the voltage generated by charging unit 33 can reach 1.6V, which is a multiple of that of power supply 20. This meets the minimum driving voltage requirement of buzzer module 10, allowing buzzer module 10 to sound normally. In practical applications, it can also ensure that buzzer module 10 works normally under other low voltage conditions.

[0032] In this embodiment, the first switching unit is turned on to charge the charging unit through the power supply to generate a multiple voltage of the power supply. The multiple voltage of the power supply drives the second switching unit to turn on and drive the buzzer module to emit sound. When the power supply voltage is sufficient, the buzzer module emits a loud sound with good sound quality. The buzzer module can also emit sound normally under low power supply voltage conditions, which meets the working requirements.

[0033] In one embodiment, reference is made to Figure 2 The charging unit 33 includes a bootstrap capacitor C1 and a pull-up resistor R1. The bootstrap capacitor C1 has a first terminal and a second terminal. The first terminal of the bootstrap capacitor C1 is connected to the first switching unit 31 and one end of the pull-up resistor R1. The second terminal of the bootstrap capacitor C1 is connected to the second switching unit 32 and the power supply 20. The other end of the pull-up resistor R1 is connected to the power supply 20. The first switching unit 31 is turned on, grounding the first terminal of the bootstrap capacitor C1. In a specific implementation, the charging unit 33 includes a bootstrap capacitor C1 and a pull-up resistor R1. The bootstrap capacitor C1 is a capacitor element capable of storing electrical energy. The bootstrap capacitor C1 has a first terminal and a second terminal, which are the two ends of the bootstrap capacitor C1. Figure 2As shown, the first and second terminals of the bootstrap capacitor C1 are represented by a and b, respectively. The first terminal of the bootstrap capacitor C1 is connected to the first switching unit 31 and one end of the pull-up resistor R1. The second terminal of the bootstrap capacitor C1 is connected to the second switching unit 32 and the power supply 20, while the other end of the pull-up resistor R1 is connected to the power supply 20. The pull-up resistor R1 is mainly used to pull up the voltage of the first terminal of the bootstrap capacitor C1 to be the same as the voltage of the power supply 20. The first switching unit 31 is controlled by the level signal of the pulse signal source 21 to turn on and off. When the first switching unit 31 is on, the first terminal of the bootstrap capacitor C1 is grounded. Specifically, when the first switching unit 31 is off, the first terminal of the bootstrap capacitor C1 is not connected to ground. When the first switching unit 31 is on, the first terminal of the bootstrap capacitor C1 is connected to ground. In practical applications, when the first switching unit 31 is turned on and the first terminal of the bootstrap capacitor C1 is grounded, the voltage at the first terminal of the bootstrap capacitor C1 is the ground voltage of 0V. The second terminal of the bootstrap capacitor C1 is connected to the power supply 20, so the voltage at the second terminal of the bootstrap capacitor C1 is equal to the voltage VCC of the power supply 20. There is a voltage difference VCC between the voltage at the first terminal and the second terminal of the bootstrap capacitor C1, so the bootstrap capacitor C1 is charged. The second switching unit 32 is connected to the second terminal of the bootstrap capacitor C1. The voltage at the second terminal of the bootstrap capacitor C1 is insufficient to turn on the second switching unit 32. Therefore, the buzzer module 10 is not powered and the buzzer module 10 does not work. When the first switching unit 31 is disconnected, the pull-up resistor R1 pulls the voltage at the first terminal of the bootstrap capacitor C1 up to the voltage VCC of the power supply 20. The voltage at the first terminal of the bootstrap capacitor C1 is floating, while the voltage at the second terminal of the bootstrap capacitor C1 is equal to the voltage VCC of the power supply 20. Since the voltage difference between the first and second terminals of the bootstrap capacitor C1 cannot change abruptly, the voltage at the second terminal of the bootstrap capacitor C1 is the sum of the voltages at the first terminal. Therefore, the voltage at the second terminal of the bootstrap capacitor C1 is VCC + VCC = 2VCC. That is, the second terminal of the bootstrap capacitor C1 generates a voltage that is a multiple of the voltage of the power supply 20, which is 2VCC. The second switching unit 32 is connected to the second terminal of the bootstrap capacitor C1. The voltage 2VCC, a multiple of the power supply 20 generated at the second terminal of the bootstrap capacitor C1, enables the second switching unit 32 to enter a conducting state. This allows the voltage 2VCC generated at the second terminal of the bootstrap capacitor C1 to be input to the buzzer module 10 via the second switching unit 32, energizing the buzzer module 10. The input voltage is a multiple of the power supply 20. When the power supply 20 voltage is sufficient, this multiple voltage enhances the vibration amplitude of the buzzer module 10, resulting in a louder and better-quality sound. Even when the power supply 20 voltage is low, within a certain range below the minimum operating voltage of the buzzer module 10, the multiple voltage can still meet the minimum operating voltage requirement, allowing the buzzer module 10 to operate normally.

[0034] Furthermore, referring to Figure 2 The charging unit 33 further includes a first diode D1. The cathode of the first diode D1 is connected to the second terminal of the bootstrap capacitor C1 and the second switching unit 32, and the anode of the first diode D1 is connected to the power supply 20. Specifically, the charging unit 33 further includes a first diode D1, with the cathode of the first diode D1 connected to the second terminal of the bootstrap capacitor C1 and the second switching unit 32, and the anode of the first diode D1 connected to the power supply 20. Due to the unidirectional conductivity of the first diode D1, it can be ensured that the current flowing from the power supply 20 flows into the second terminal of the bootstrap capacitor C1, thus ensuring the stability of the voltage at the second terminal of the bootstrap capacitor C1.

[0035] Furthermore, referring to Figure 2 The first switching unit 31 includes a first switching transistor Q1, which has an input terminal, an output terminal, and a control terminal. The control terminal of the first switching transistor Q1 is connected to the pulse signal source 21. The input terminal of the first switching transistor Q1 is connected to the first terminal of the bootstrap capacitor C1, and the output terminal of the first switching transistor Q1 is grounded. Specifically, the first switching unit 31 includes a first switching transistor Q1, which has an input terminal, an output terminal, and a control terminal. The first switching transistor Q1 can be designed as a MOSFET, a transistor, or other switching devices; no limitation is made here. The control terminal of the first switching transistor Q1 is connected to the pulse signal source 21, the input terminal of the first switching transistor Q1 is connected to the first terminal of the bootstrap capacitor C1, and the output terminal of the first switching transistor Q1 is grounded. In practical applications, the control terminal of the first switching transistor Q1 receives a level signal from the pulse signal source 21 to control the on / off state of its input and output terminals. When the input and output terminals of the first switching transistor Q1 are on, the first terminal of the bootstrap capacitor C1 is grounded; when the input and output terminals of the first switching transistor Q1 are off, the first terminal of the bootstrap capacitor C1 remains floating. Different level signals are output from the pulse signal source 21 to control the voltage at the first terminal of the bootstrap capacitor C1, allowing the voltage at the first terminal of the bootstrap capacitor C1 to switch between the power supply voltage VCC and the ground voltage 0V. This enables the second terminal of the bootstrap capacitor C1 to generate a voltage multiple of the power supply voltage 20 to drive the buzzer module 10 to produce sound.

[0036] Specifically, refer to Figure 2The first switching unit 31 further includes a first current-limiting resistor R3. The first switching transistor Q1 is an NPN transistor. The input terminal of the first switching transistor Q1 is the collector of the NPN transistor, the output terminal is the emitter of the NPN transistor, and the control terminal is the base of the NPN transistor. One end of the first current-limiting resistor R3 is connected to the base of the NPN transistor, and the other end is connected to the pulse signal source 21. In a specific implementation, the first switching unit 31 further includes a first current-limiting resistor R3. The first switching transistor Q1 is designed to be an NPN transistor. The input terminal, output terminal, and control terminal of the first switching transistor Q1 correspond to the collector, emitter, and base of the NPN transistor, respectively. One end of the first current-limiting resistor R3 is connected to the base of the NPN transistor, and the other end of the first current-limiting resistor R3 is connected to the pulse signal source 21. That is, the first current-limiting resistor R3 is connected in series between the pulse signal source 21 and the base of the NPN transistor. The first current-limiting resistor R3 can prevent the NPN transistor from being connected to the base of the NPN transistor. Excessive base current of the NPN transistor can break down the PN junction. The emitter of the NPN transistor is grounded. When the pulse signal source 21 outputs a high-level signal, the NPN transistor is turned on; when the pulse signal source 21 outputs a low-level signal, the NPN transistor is turned off. By outputting high and low level signals through the pulse signal source 21, the on / off control of the NPN transistor can be easily achieved, thereby controlling the voltage at the first terminal of the bootstrap capacitor C1. This causes the second terminal of the bootstrap capacitor C1 to generate a voltage multiple of the power supply 20 to drive the buzzer module 10 to work and produce sound.

[0037] In one embodiment, reference is made to Figure 2The second switching unit 32 includes a second switching transistor Q2, which has an input terminal, an output terminal, and a control terminal. The control terminal of the second switching transistor Q2 is connected to the anode of the first diode D1 and the power supply 20. The input terminal is connected to the second terminal of the bootstrap capacitor C1 and the cathode of the first diode D1. The output terminal is connected to the buzzer module 10. The second switching transistor Q2 is turned on when the input voltage is greater than the control voltage. In a specific implementation, the second switching unit 32 includes a second switching transistor Q2, which also has an input terminal, an output terminal, and a control terminal. The second switching transistor Q2 can be the same type as the first switching transistor Q1, or it can be a different type of switching transistor. The second switching transistor Q2 can be designed as a MOSFET, a transistor, or other switching devices; no restrictions are placed here. The control terminal of the second switch Q2 is connected to both the anode of the first diode D1 and the power supply 20. The input terminal of the second switch Q2 is connected to the second terminal of the bootstrap capacitor C1 and the cathode of the first diode D1. The output terminal of the second switch Q2 is grounded. The conduction condition of the second switch Q2 is that the voltage at the input terminal of the second switch Q2 is greater than the voltage at the control terminal. If the voltage at the input terminal of the second switch Q2 is less than or equal to the voltage at the control terminal, the second switch Q2 is in a state where the input and output terminals are disconnected. In practical applications, the control terminal of the second switch Q2 is connected to the power supply 20. Therefore, the voltage at the control terminal of the second switch Q2 is equal to the voltage of the power supply 20 and is a fixed value. The voltage at the second terminal of the bootstrap capacitor C1 is applied to the input terminal of the second switch Q2. The conduction or disconnection of the second switch Q2 is determined by the voltage at the second terminal of the bootstrap capacitor C1. When the first switch Q1 is conducting, the voltage at the second terminal of the bootstrap capacitor C1 is the same as the voltage of the power supply 20. Therefore, the voltage at the control terminal of the second switch Q2 is equal to the voltage at the input terminal. The input and output terminals of the second switch Q2 are disconnected, the buzzer module 10 is not powered, and the buzzer module 10 does not work. With the first switch Q1 off, the second terminal of the bootstrap capacitor C1 generates a voltage multiple of the power supply 20, which is applied to the input terminal of the second switch Q2. Therefore, the voltage at the control terminal of the second switch Q2 is less than the voltage at the input terminal, and the input and output terminals of the second switch Q2 are connected. This allows the voltage multiple of the power supply 20 at the second terminal of the bootstrap capacitor C1 to be input to the buzzer module 10 via the second switch Q2, thereby powering up and enabling the buzzer module 10 to operate.

[0038] Furthermore, referring to Figure 2The second switching unit 32 further includes a second current-limiting resistor R5. The second switching transistor Q2 is a PNP transistor. The input terminal of the second switching transistor Q2 is the emitter of the PNP transistor, the output terminal is the collector of the PNP transistor, and the control terminal is the base of the PNP transistor. One end of the second current-limiting resistor R5 is connected to the base of the PNP transistor, and the other end is connected to the power supply 20 and the anode of the first diode D1. In specific implementation, the second switching unit 32 also includes a second current-limiting resistor R5. The second switching transistor Q2 is designed to be a PNP transistor. The input, output, and control terminals of the second switching transistor Q2 correspond to the emitter, collector, and base of the PNP transistor, respectively. One end of the second current-limiting resistor R5 is connected to the base of the PNP transistor, and the other end of the second current-limiting resistor R5 is connected to the power supply 20 and the anode of the first diode D1. The current from the power supply 20 flows through the second current-limiting resistor R5 to the base of the PNP transistor. The second current-limiting resistor R5 can prevent the base current of the PNP transistor from being too large and breaking down the PN junction of the PNP transistor. The emitter of the PNP transistor is connected to the input terminal of the buzzer module 10. In practical applications, the conduction condition of a PNP transistor is that the emitter voltage is greater than the base voltage. Therefore, when the second terminal of the bootstrap capacitor C1 does not generate a multiple of the power supply voltage 20, the emitter voltage and the base voltage of the transistor are equal to VCC, and the PNP transistor is cut off. After the second terminal of the bootstrap capacitor C1 generates a multiple of the power supply voltage 20, the emitter voltage of the transistor is greater than the base voltage, and the PNP transistor is turned on, so that the multiple of the power supply voltage 20 generated at the second terminal of the bootstrap capacitor C1 can be input to drive the buzzer module 10 to drive it to work and make a sound.

[0039] In one embodiment, reference is made to Figure 2 The voltage multiplier module 30 further includes a discharge unit 34. The buzzer module 10 has a first input terminal and a second input terminal. The first input terminal is connected to the output terminal of the second switching transistor Q2, and the second input terminal is grounded. The discharge unit 34 is connected to the first input terminal and the second input terminal, wherein the discharge unit 34 is used to discharge the bootstrap capacitor C1. In a specific implementation, the voltage multiplier module 30 further includes a discharge unit 34, which is specifically designed using a resistor or other load device with fast power consumption. The buzzer module 10 has a first input terminal and a second input terminal, which are specifically the positive and negative inputs of the buzzer module 10, such as... Figure 2As shown, c and d represent the first and second input terminals of the buzzer module 10. The first input terminal of the buzzer module 10 is connected to the output terminal of the second switching transistor Q2, while the second input terminal of the buzzer module 10 is grounded. The discharge unit 34 is connected to both the first and second input terminals of the buzzer module 10. In practical applications, when the pulse signal source 21 changes from having a signal output to having no signal output, i.e., when the level signal output by the pulse signal source 21 disappears, the voltage at the second terminal of the bootstrap capacitor C1 passes through the buzzer module 10 and the discharge unit 34 to ground. The discharge unit 34 consumes electrical energy, causing the bootstrap capacitor C1 to discharge rapidly, which can effectively prevent voltage superposition caused by subsequent circuit power-on.

[0040] Furthermore, referring to Figure 2 The discharge unit 34 includes a first resistor R2, one end of which is connected to the first input terminal, and the other end of which is connected to the second input terminal. Specifically, the discharge unit 34 includes the first resistor R2, one end of which is connected to the first input terminal of the buzzer module 10, and the other end of which is connected to the second input terminal of the buzzer module 10 to ground. In practical applications, when the pulse signal source 21 changes from having a signal output to having no signal output, the voltage at the second terminal of the bootstrap capacitor C1 passes through the buzzer module 10 and the discharge unit 34 to ground. The first resistor R2 releases the electrical energy of the bootstrap capacitor C1 in the form of heat, thus discharging the bootstrap capacitor C1.

[0041] In one embodiment, to better understand the working principle of the buzzer voltage multiplier drive circuit, the following is combined with... Figure 2 The specific operation process of the buzzer voltage doubler drive circuit will be explained.

[0042] Please see Figure 2 VCC represents the power supply, and V1 represents the pulse signal source. The high and low level signals output by V1 determine the working state of the buzzer module U3. In specific applications, the pulse signal source V1 and the power supply VCC have the following states:

[0043] (1) When there is no output signal at V1 or the voltage at VCC is zero, transistors Q1 and Q2 are cut off in this state, and there is no voltage on the buzzer module U3, so the buzzer module U3 cannot make a sound.

[0044] (2) When the output signal of V1 is high, transistor Q1 is turned on, and terminal a of capacitor C1 will be grounded as transistor Q1 is turned on. Therefore, the potential of terminal a of capacitor C1 is pulled low, i.e., terminal a is low level. Terminal b of capacitor C1 is connected to VCC through diode D1, and the potential of terminal b is pulled up. Therefore, the potential of terminal b is approximately equal to VCC, and terminal b of capacitor C1 is high level. At this time, there is a potential difference between terminals a and b of capacitor C1, and capacitor C1 is charging. The base of transistor Q2 is connected to VCC through resistor R5, pulling up the base potential of transistor Q2. Therefore, the base voltage of transistor Q2 is VCC. The emitter of transistor Q2 is connected to terminal b of capacitor C1, so the emitter voltage of transistor Q2 is also VCC. Transistor Q2 is a PNP transistor, which only conducts when its emitter voltage is greater than its base voltage. Therefore, at this time, transistor Q2 is cut off, the buzzer module U3 is not powered, and the buzzer module U3 does not work.

[0045] (3) When the output signal of V1 changes from high level to low level, transistor Q1 is cut off, and terminal a of capacitor C1 is connected to power supply VCC through resistor R1. The potential of terminal a of capacitor C1 is pulled up, so the potential of terminal a of capacitor C1 is VCC. Since the voltage across capacitor C1 cannot change abruptly, the potential of terminal b of capacitor C1 is VCC + VCC = 2VCC, which is the sum of the potentials of terminal a. At this time, the potential of the cathode of diode D1 is higher than that of the anode. Due to the unidirectional conductivity of diode D1, the base of transistor Q2 is still pulled up to the potential VCC, while the potential of the emitter of transistor Q2 is equal to that of capacitor C1. When the voltage at terminal b of capacitor C1 is 2VCC, transistor Q2 conducts, and the voltage at terminal b of capacitor C1 is input to buzzer module U3, causing buzzer module U3 to be powered on. At this time, the driving voltage of buzzer module U3 is the voltage at terminal b of capacitor C1, which is 2VCC. That is, the driving voltage of buzzer module U3 is twice the voltage of power supply VCC. When the power supply VCC voltage is sufficient, the buzzer module U3 produces a loud sound with good sound quality. When the power supply VCC voltage is low, within a certain range below the minimum driving voltage of buzzer module U3, buzzer module U3 can still produce sound normally.

[0046] (4) When V1 changes from having a signal output to having no signal output, this state is when the pulse signal source stops outputting a signal. The voltage at the b end of capacitor C1 goes to ground through the buzzer module U3 and resistor R2. Resistor R2 quickly consumes electrical energy, causing capacitor C1 to discharge quickly, preventing voltage superposition caused by subsequent circuit power-on.

[0047] Through this embodiment, when the power supply voltage is sufficient, the buzzer module can produce a loud and high-quality sound. Under low power supply voltage conditions, the buzzer module can also produce sound normally, meeting the working requirements.

[0048] In one embodiment, an electronic device is provided, which includes the buzzer voltage multiplier drive circuit described in the above embodiment. This electronic device is primarily battery-powered and can specifically be a smoke alarm, metal detector, electronic toy, or other device that uses a buzzer. The buzzer voltage multiplier drive circuit is integrated into this electronic device to drive the buzzer to produce sound. Since the specific structure and working principle of the buzzer voltage multiplier drive circuit have already been described in detail in the preceding specification, they will not be repeated here for the sake of brevity.

[0049] The electronic device in this embodiment, due to the use of the buzzer voltage doubler drive circuit provided by the present invention, can still emit sound normally under low power supply conditions, and the device can work effectively for a longer time under low voltage conditions.

[0050] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A buzzer voltage doubler drive circuit, characterized in that, include: Buzzer module, used to produce sound; A voltage multiplier module includes a first switching unit, a second switching unit, and a charging unit. The charging unit is connected to a power source. The first switching unit is connected to the charging unit. The second switching unit is connected to the power source, the charging unit, and the buzzer module. The first switching unit is controlled to turn on and off by a pulse signal source. When the first switching unit is turned on, the charging unit is charged by the power supply to generate a multiple voltage of the power supply. The multiple voltage of the power supply controls the second switching unit to turn on and drive the buzzer module to sound. The charging unit includes a bootstrap capacitor, a pull-up resistor, and a first diode. The bootstrap capacitor has a first terminal and a second terminal. The first terminal of the bootstrap capacitor is connected to the first switching unit and one terminal of the pull-up resistor. The second terminal of the bootstrap capacitor is connected to the second switching unit and the power supply. The other terminal of the pull-up resistor is connected to the power supply. The first switching unit is turned on to ground the first terminal of the bootstrap capacitor. The cathode of the first diode is connected to the second terminal of the bootstrap capacitor and the second switching unit, and the anode of the first diode is connected to the power supply. The second switching unit includes a second switching transistor, which has an input terminal, an output terminal, and a control terminal. The control terminal of the second switching transistor is connected to the anode of the first diode and the power supply, the input terminal is connected to the second terminal of the bootstrap capacitor and the cathode of the first diode, and the output terminal is connected to the buzzer module. The voltage at the input terminal of the second switching transistor is greater than the voltage at the control terminal to turn on the second switching transistor.

2. The buzzer voltage doubler drive circuit according to claim 1, characterized in that, The first switching unit includes a first switching transistor, which has an input terminal, an output terminal, and a control terminal. The control terminal of the first switching transistor is connected to the pulse signal source, the input terminal of the first switching transistor is connected to the first terminal of the bootstrap capacitor, and the output terminal of the first switching transistor is grounded.

3. The buzzer voltage doubler drive circuit according to claim 2, characterized in that, The first switching unit further includes a first current-limiting resistor. The first switching transistor is an NPN transistor. The input terminal of the first switching transistor is the collector of the NPN transistor, the output terminal is the emitter of the NPN transistor, and the control terminal is the base of the NPN transistor. One end of the first current-limiting resistor is connected to the base of the NPN transistor, and the other end is connected to the pulse signal source.

4. The buzzer voltage doubler drive circuit according to claim 1, characterized in that, The second switching unit further includes a second current-limiting resistor. The second switching transistor is a PNP transistor. The input terminal of the second switching transistor is the emitter of the PNP transistor, the output terminal is the collector of the PNP transistor, and the control terminal is the base of the PNP transistor. One end of the second current-limiting resistor is connected to the base of the PNP transistor, and the other end is connected to the power supply and the anode of the first diode.

5. The buzzer voltage doubler drive circuit according to claim 1, characterized in that, The voltage multiplier module further includes a discharge unit. The buzzer module has a first input terminal and a second input terminal. The first input terminal is connected to the output terminal of the second switching transistor, and the second input terminal is grounded. The discharge unit is connected to the first input terminal and the second input terminal. The discharge unit is used to discharge the bootstrap capacitor.

6. The buzzer voltage doubler drive circuit according to claim 5, characterized in that, The discharge unit includes a first resistor, one end of which is connected to the first input terminal, and the other end of which is connected to the second input terminal.

7. An electronic device, characterized in that, Includes the buzzer voltage multiplier drive circuit according to any one of claims 1-6.

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