Buzzer voltage-multiplying driving circuit and electronic equipment

Abstract

The invention discloses a buzzer voltage-multiplying driving circuit and electronic equipment, and the circuit comprises a buzzer module which is used for generating sound; the voltage-multiplying module comprises a first switch unit, a second switch unit and an energy charging unit, the energy charging unit is connected with the power supply, the first switch unit is connected with the energy charging unit, and the second switch unit is connected with the power supply, the energy charging unit and the buzzer module; wherein the first switch unit controls on-off through a pulse signal source, when the first switch unit is switched on, the energy charging unit charges energy through 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 switched on and then drives the buzzer module to make a sound. According to the buzzer voltage-multiplying driving circuit, the buzzer module is driven to produce sound by generating the multiple voltage of the power supply, the volume is large and the sound quality is good when the buzzer module produces sound, the buzzer module can produce sound normally under the condition of low voltage of the power supply, and the working requirement is met.

Description

Technical Field

[0001] The present invention relates to the technical field of buzzer drive circuits, and in particular to a buzzer voltage doubling drive circuit and electronic equipment. Background Art

[0002] Buzzers are a common acoustic device that generates sound through electromagnetic or piezoelectric effects. Buzzers are widely used in alarms, prompts, notifications, and other scenarios. When a buzzer is used on a battery-powered device, it may not work properly under low device and low voltage conditions. For example, the buzzer on a remote monitoring system device or some portable devices may have low battery power but not exhausted after a long period of use. The power supply voltage provided by the battery is low. In this case, when the internal drive circuit of the device drives the buzzer to sound, the buzzer cannot sound normally or even does not respond. The operation of the buzzer is limited by low voltage conditions, making the device unable to work effectively under low voltage conditions. Summary of the invention

[0003] The embodiments of the present invention provide a buzzer voltage doubling driving circuit and an electronic device, which solve the problem that the buzzer cannot sound normally under the condition of low power supply voltage.

[0004] In a first aspect, an embodiment of the present invention provides a buzzer voltage doubling driving circuit, comprising:

[0005] Buzzer module, used for making sounds;

[0006] A voltage doubling module, comprising a first switch unit, a second switch unit and a charging unit, wherein the charging unit is connected to a power source, the first switch unit is connected to the charging unit, and the second switch unit is connected to the power source, the charging unit and the buzzer module;

[0007] Among them, the first switch unit is controlled to be on and off by a pulse signal source. When the first switch 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 switch unit to be turned on and then drives the buzzer module to make a sound.

[0008] In the buzzer voltage doubling drive circuit provided in an 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 switch unit and one end of the pull-up resistor, the second end of the bootstrap capacitor is connected to the second switch unit and the power supply, and the other end of the pull-up resistor is connected to the power supply, wherein the first switch unit is turned on to ground the first end of the bootstrap capacitor.

[0009] In the buzzer voltage doubling driving circuit provided in an embodiment of the present invention, the charging unit further includes a first diode, a cathode of the first diode is connected to the second end of the bootstrap capacitor and the second switch unit, and an anode of the first diode is connected to the power supply.

[0010] In the buzzer voltage doubling driving circuit provided in an embodiment of the present invention, the first switch unit includes a first switch tube, the first switch tube is provided with an input end, an output end and a control end, the control end of the first switch tube is connected to the pulse signal source, the input end of the first switch tube is connected to the first end of the bootstrap capacitor, and the output end of the first switch tube is grounded.

[0011] In the buzzer voltage doubling drive circuit provided in an embodiment of the present invention, the first switching unit also includes a first current limiting resistor, the first switching tube is an NPN transistor, the input end of the first switching tube is the collector of the NPN transistor, the output end is the emitter of the NPN transistor, the control end 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 doubling drive circuit provided in an embodiment of the present invention, the second switch unit includes a second switch tube, the second switch tube is provided with an input end, an output end and a control end, the control end of the second switch tube is connected to the anode of the first diode and the power supply, the input end is connected to the second end of the bootstrap capacitor and the cathode of the first diode, and the output end is connected to the buzzer module, wherein the input end voltage of the second switch tube is greater than the control end voltage to turn on the second switch tube.

[0013] In the buzzer voltage doubling drive circuit provided in an embodiment of the present invention, the second switch unit also includes a second current limiting resistor, the second switch tube is a PNP transistor, the input end of the second switch tube is the emitter of the PNP transistor, the output end is the collector of the PNP transistor, the control end 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 doubling driving circuit provided in an embodiment of the present invention, the voltage doubling module also 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 switch tube, the second input terminal is grounded, and the discharge unit is connected to the first input terminal and the second input terminal, wherein the discharge unit is used to discharge the bootstrap capacitor.

[0015] In the buzzer voltage doubler driving circuit provided by 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 end, and the other end of the first resistor is connected to the second input end.

[0016] In a second aspect, an embodiment of the present invention provides an electronic device, comprising the buzzer voltage doubling driving circuit described in the first aspect.

[0017] The embodiment of the present invention provides a buzzer voltage doubling driving circuit and an electronic device, the buzzer voltage doubling driving circuit comprising: a buzzer module for making a sound; a voltage doubling module comprising a first switch unit, a second switch unit and a charging unit, the charging unit being connected to a power supply, the first switch unit being connected to the charging unit, and the second switch unit being connected to the power supply, the charging unit and the buzzer module; wherein the first switch unit is controlled to be on and off by a pulse signal source, and when the first switch unit is turned on, the charging unit is charged by the power supply to generate a 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 make a sound. The buzzer voltage doubling driving circuit of the present application enables the charging unit to be charged by the power supply to generate a multiple voltage of the power supply by turning on the first switch unit, and drives the buzzer module to make a sound after the second switch unit is turned on by the multiple voltage of the power supply, so that the buzzer module has a large volume and good sound quality when making a sound, and the buzzer module can make a sound normally under the condition of low power supply voltage, meeting the working requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0019] Figure 1 A structural block diagram of a buzzer voltage doubling driving circuit provided by an embodiment of the present invention;

[0020] Figure 2 A circuit diagram of a buzzer voltage doubling driving circuit provided by an embodiment of the present invention;

[0021] The reference numerals in the figures are:

[0022] 10. Buzzer module; 20. Power supply; 21. Pulse signal source; 30. Voltage doubling module; 31. First switch unit; 32. Second switch unit; 33. Charging unit; 34. Discharging unit. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

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

[0026] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

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

[0028] In order to facilitate understanding of the present invention, the buzzer voltage doubling driving circuit provided by the embodiment of the present invention is first described. Figure 1 and Figure 2An embodiment of the present invention provides a buzzer voltage doubling driving circuit, which includes: a buzzer module 10, which is used to make a sound; a voltage doubling module 30, which includes a first switch unit 31, a second switch unit 32 and a charging unit 33, wherein the charging unit 33 is connected to a power supply 20, the first switch unit 31 is connected to the charging unit 33, and the second switch unit 32 is connected to the power supply 20, the charging unit 33 and the buzzer module 10; wherein the first switch unit 31 is controlled to be on and off by a pulse signal source 21, and when the first switch unit 31 is turned on, the charging unit 33 is charged by the power supply 20 to generate a multiple voltage of the power supply 20, and the multiple voltage of the power supply 20 controls the second switch unit 32 to be turned on and then drives the buzzer module 10 to make a sound.

[0029] In specific implementation, in traditional buzzer driving circuits, a transistor circuit is mostly used to drive the buzzer to make sound. After the transistor is driven to conduct, the voltage provided by the power supply is directly input into the buzzer to drive it to make sound. When the power supply is in a low voltage condition, the voltage provided by the power supply cannot maintain the normal operation of the buzzer, making the buzzer sound small and intermittent, or even without sound.

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

[0031] The buzzer voltage-doubling driving circuit of the present embodiment can be applied to various electronic devices, mainly battery-powered electronic devices, such as smoke alarms, metal detectors and other equipment. The buzzer voltage-doubling driving circuit of the present embodiment includes a buzzer module 10 and a voltage-doubling module 30. The buzzer module 10 is mainly used for sounding. The principle of sounding of the buzzer module 10 is to generate sound through electromagnetic or piezoelectric effect. The buzzer module 10 of the present embodiment is an active buzzer module 10, that is, the buzzer module 10 has its own oscillation source inside. It only needs to apply a driving voltage to the input end of the buzzer module 10 to make it sound. The voltage-doubling module 30 includes a first switch unit 31, a second switch unit 32 and a charging unit 33. The charging unit 33 is connected to the power supply 20. The first switch unit 31 is connected to the charging unit 33, and the second switch unit 32 is connected to the power supply 20, the charging unit 33 and the buzzer module 10. Specifically, the first switch unit 31 is specifically a unit composed of switch devices, for example, it can be composed of switch devices such as switch tubes (MOS tubes, transistors), relays, optocoupler switches, etc. In actual circuit applications, the pulse signal source 21 is connected to the power supply 20, and the first switch unit 31 is connected to the pulse signal source 21. The first switch unit 31 is controlled to be on and off by the pulse signal source 21. The pulse signal source 21 controls the on and off of the first switch unit 31 by sending high and low level signal pulses. The pulse signal source 21 can specifically be a microprocessor, an oscillator circuit, etc., which can send high and low level signal pulses. Here, whether the buzzer module 10 needs to make a sound is mainly determined by the level signal output by the pulse signal source 21. When the pulse signal source 21 sends a pulse signal to control the first switch unit 31 to be turned on, the charging unit 33 is charged through the power supply 20, that is, the first switch unit 31 is used as the charging switch of the charging unit 33. The charging unit 33 is designed in coordination with capacitors and other components, and utilizes the principle that the capacitor voltage cannot change suddenly, so that the charging unit 33 generates a multiple voltage of the power supply 20 after charging. The multiple voltage of the power supply 20 is a multiple of the voltage of the power supply 20, which is specifically designed to be an integer multiple. For example, the voltage of the power supply 20 is 3.3V. Taking the voltage of 2 times 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 switch unit 32 is connected to the power supply 20, the charging unit 33 and the buzzer module 10, and serves as a switch between the charging unit 33 and the buzzer module 10. The on and off of the second switch unit 32 is mainly controlled by the voltage on the charging unit 33. The second switch unit 32 is turned on by the multiple voltage of the power supply 20 generated on the charging unit 33. The specific turn-on condition of the second switch unit 32 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 switch unit 32 is in the disconnected state. The multiple voltage of the power supply 20 can turn on the second switch unit 32.After the second switch unit 32 is turned on, the multiple voltage of the power supply 20 is input to the input end of the buzzer module 10 through the second switch unit 32, driving the buzzer module 10 to make a sound, and 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. Under the condition that the voltage of the power supply 20 is sufficient, the multiple voltage of the power supply 20 can enhance the vibration amplitude of the buzzer module 10, so that the volume of the buzzer module 10 is louder and the sound quality is better when the buzzer module 10 sounds. Under the condition that the power supply 20 voltage is low, the voltage of the power supply 20 is lower than the minimum driving voltage of the buzzer module 10 within a certain range, and the multiple voltage of the power supply 20 can also meet the minimum driving voltage requirement of the buzzer module 10 to the greatest extent, so that the buzzer module 10 can make a sound normally. For example, the minimum driving voltage requirement of the buzzer module 10 is 1.5V. When the voltage of the power supply 20 is 0.8V, the voltage multiple of the power supply 20 generated on the charging unit 33 can reach 1.6V, which meets the minimum driving voltage requirement of the buzzer module 10 and enables the buzzer module 10 to sound normally. In actual applications, in the face of other low voltage conditions, the buzzer module 10 can also work normally to the greatest extent.

[0032] In this embodiment, the charging unit is charged by the power supply by turning on the first switch unit to generate a multiple voltage of the power supply, and the multiple voltage of the power supply drives the second switch unit to turn on and then drives the buzzer module to make a sound. Under the condition of sufficient power supply voltage, the buzzer module has a loud volume and good sound quality, and the buzzer module can also make a sound normally under the condition of low power supply voltage, meeting the working requirements.

[0033] In one embodiment, referring to Figure 2 , the energy charging unit 33 includes a bootstrap capacitor C1 and a pull-up resistor R1, the bootstrap capacitor C1 has a first end and a second end, the first end of the bootstrap capacitor C1 is connected to the first switch unit 31 and one end of the pull-up resistor R1, the second end of the bootstrap capacitor C1 is connected to the second switch unit 32 and the power supply 20, and the other end of the pull-up resistor R1 is connected to the power supply 20, wherein the first switch unit 31 is turned on to ground the first end of the bootstrap capacitor C1. In a specific implementation, the energy charging unit 33 includes a bootstrap capacitor C1 and a pull-up resistor R1, the bootstrap capacitor C1 is a capacitive element that can store electrical energy, the bootstrap capacitor C1 has a first end and a second end, the first end and the second end are the two ends of the bootstrap capacitor C1, as Figure 2As shown, the first end and the second end of the bootstrap capacitor C1 are represented by a and b respectively. The first end of the bootstrap capacitor C1 is connected to the first switch unit 31 and is connected to one end of the pull-up resistor R1, the second end of the bootstrap capacitor C1 is connected to the second switch unit 32 and the power supply 20, and 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 end of the bootstrap capacitor C1 to the same voltage as the power supply 20. The first switch unit 31 is controlled to be turned on and off by the level signal of the pulse signal source 21. The conduction of the first switch unit 31 grounds the first end of the bootstrap capacitor C1. Specifically, when the first switch unit 31 is disconnected, the first end of the bootstrap capacitor C1 is not connected to the ground, and when the first switch unit 31 is turned on, the first end of the bootstrap capacitor C1 is connected to the ground. In actual application, when the first switch unit 31 is turned on to ground the first end of the bootstrap capacitor C1, the voltage at the first end of the bootstrap capacitor C1 is the ground voltage 0V, and the second end of the bootstrap capacitor C1 is connected to the power supply 20, so the voltage at the second end of the bootstrap capacitor C1 is equal to the voltage VCC of the power supply 20, and there is a voltage difference VCC between the first end voltage and the second end of the bootstrap capacitor C1, the bootstrap capacitor C1 is charged, the second switch unit 32 is connected to the second end of the bootstrap capacitor C1, and the voltage at the second end of the bootstrap capacitor C1 is insufficient to turn on the second switch unit 32, so the buzzer module 10 is not powered and does not work. When the first switch unit 31 is disconnected, the pull-up resistor R1 pulls up the voltage of the first end of the bootstrap capacitor C1 to the voltage VCC of the power supply 20, the voltage of the first end of the bootstrap capacitor C1 is suspended, and the voltage of the second end of the bootstrap capacitor C1 is equal to the voltage VCC of the power supply 20, the voltage of the first end of the bootstrap capacitor C1 is equal to the voltage VCC of the power supply 20, and the voltage of the first end and the voltage of the second end of the bootstrap capacitor C1 are both equal to VCC. Since the voltage difference across the bootstrap capacitor C1 cannot change suddenly, the voltage of the second end of the bootstrap capacitor C1 is superimposed according to the voltage of the first end, so the voltage of the second end of the bootstrap capacitor C1 is VCC+VCC=2VCC, that is, the second end of the bootstrap capacitor C1 generates a multiple voltage of the power supply 20 of 2VCC. The second switch unit 32 is connected to the second end of the bootstrap capacitor C1. The multiple voltage 2VCC of the power supply 20 generated by the second end of the bootstrap capacitor C1 can make the second switch unit 32 enter the on state, so that the multiple voltage 2VCC of the power supply 20 generated by the second end of the bootstrap capacitor C1 is input to the buzzer module 10 through the second switch unit 32, and the buzzer module 10 is powered on and works, and the input voltage is a multiple voltage of the power supply 20. Under the condition that the voltage of the power supply 20 is sufficient, the multiple voltage of the power supply 20 can enhance the vibration amplitude of the buzzer module 10, so that the volume of the buzzer module 10 is louder and the sound quality is better. Under the condition that the power supply 20 is low voltage, when the voltage of the power supply 20 is lower than the minimum working voltage of the buzzer module 10 within a certain range, the multiple voltage of the power supply 20 can also meet the minimum working voltage requirement of the buzzer module 10, so that the buzzer module 10 can sound normally.

[0034] Further, refer 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 end of the bootstrap capacitor C1 and the second switch unit 32, and the anode of the first diode D1 is connected to the power supply 20. In a specific implementation, the charging unit 33 further includes a first diode D1, the cathode of the first diode D1 is connected to the second end of the bootstrap capacitor C1 and the second switch unit 32, and the anode of the first diode D1 is connected to the power supply 20. Due to the unidirectional conductivity of the first diode D1, it can be ensured that the current of the power supply 20 flows into the second end of the bootstrap capacitor C1, thereby ensuring the stability of the voltage at the second end of the bootstrap capacitor C1.

[0035] Furthermore, refer to Figure 2 , the first switch unit 31 includes a first switch tube Q1, the first switch tube Q1 is provided with an input end, an output end and a control end, the control end of the first switch tube Q1 is connected to the pulse signal source 21, the input end of the first switch tube Q1 is connected to the first end of the bootstrap capacitor C1, and the output end of the first switch tube Q1 is grounded. In a specific implementation, the first switch unit 31 includes a first switch tube Q1, the first switch tube Q1 is provided with an input end, an output end and a control end, the first switch tube Q1 can be specifically designed as a MOS tube, or can be designed as a triode or other switch tube device, which is not limited here. The control end of the first switch tube Q1 is connected to the pulse signal source 21, the input end of the first switch tube Q1 is connected to the first end of the bootstrap capacitor C1, and the output end of the first switch tube Q1 is grounded. In practical applications, the control end of the first switch tube Q1 controls the input end and the output end to be turned on or off by receiving the level signal output by the pulse signal source 21. When the input end and the output end of the first switch tube Q1 are turned on, the first end of the bootstrap capacitor C1 is grounded. When the input end and the output end of the first switch tube Q1 are disconnected, the first end of the bootstrap capacitor C1 remains suspended. The pulse signal source 21 outputs different level signals to control the voltage at the first end of the bootstrap capacitor C1, and the voltage at the first end of the bootstrap capacitor C1 is switched between the power supply 20 voltage VCC and the ground voltage 0V, so that the second end of the bootstrap capacitor C1 can generate a multiple voltage of the power supply 20 to drive the buzzer module 10 to work and make sounds.

[0036] Specifically, refer to Figure 2, the first switch unit 31 also includes a first current limiting resistor R3, the first switch tube Q1 is an NPN transistor, the input end of the first switch tube Q1 is the collector of the NPN transistor, the output end is the emitter of the NPN transistor, the control end 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 switch unit 31 also includes a first current limiting resistor R3, the first switch tube Q1 is designed to adopt an NPN transistor, the input end, the output end, and the control end of the first switch tube Q1 correspond to the collector, the emitter, and the 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, and the first current limiting resistor R3 can prevent the NP The base current of the N transistor is too large and breaks through the PN junction of the NPN transistor. 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. The on-off control of the NPN transistor can be simply achieved by outputting high and low-level signals from the pulse signal source 21, thereby achieving voltage control on the first end of the bootstrap capacitor C1, so that the second end of the bootstrap capacitor C1 generates a voltage that is a multiple of the power supply 20 to drive the buzzer module 10 to work and make sound.

[0037] In one embodiment, referring to Figure 2, the second switch unit 32 includes a second switch tube Q2, the second switch tube Q2 is provided with an input end, an output end and a control end, the control end of the second switch tube Q2 is connected to the anode of the first diode D1 and the power supply 20, the input end is connected to the second end of the bootstrap capacitor C1 and the cathode of the first diode D1, and the output end is connected to the buzzer module 10, wherein the input end voltage of the second switch tube Q2 is greater than the control end voltage to turn on the second switch tube Q2. In a specific implementation, the second switch unit 32 includes a second switch tube Q2, the second switch tube Q2 is also provided with an input end, an output end and a control end, the second switch tube Q2 can be a switch tube of the same type as the first switch tube Q1, or a switch tube of a different type from the first switch tube Q1, the second switch tube Q2 can be designed with a MOS tube, or a triode or other switch tube device design, which is not limited here. The control end of the second switch tube Q2 is connected to the anode of the first diode D1 and the power supply 20 at the same time, the input end of the second switch tube Q2 is connected to the second end of the bootstrap capacitor C1 and the cathode of the first diode D1, and the output end of the second switch tube Q2 is grounded. The conduction condition of the second switch tube Q2 is that the input end voltage of the second switch tube Q2 is greater than the control end voltage. If the input end voltage of the second switch tube Q2 is less than or equal to the control end voltage, the second switch tube Q2 is in a state where the input end and the output end are disconnected. In practical applications, the control end of the second switch tube Q2 is connected to the power supply 20, so the voltage of the control end of the second switch tube Q2 is equal to the voltage of the power supply 20 as a fixed value, and the second end voltage of the bootstrap capacitor C1 is added to the input end of the second switch tube Q2, and the conduction or disconnection of the second switch tube Q2 is determined by the second end voltage of the bootstrap capacitor C1. When the first switch tube Q1 is turned on, the second end voltage of the bootstrap capacitor C1 is the same as the voltage of the power supply 20, so the voltage of the control end of the second switch tube Q2 is equal to the voltage of the input end, and the input end and the output end of the second switch tube Q2 are in a disconnected state, the buzzer module 10 is not powered, and the buzzer module 10 does not work. When the first switch tube Q1 is disconnected, the second end of the bootstrap capacitor C1 generates a multiple voltage of the power supply 20 and adds it to the input end of the second switch tube Q2. Therefore, the voltage of the control end of the second switch tube Q2 is less than the voltage of the input end. The input end and the output end of the second switch tube Q2 are connected, so that the multiple voltage of the power supply 20 at the second end of the bootstrap capacitor C1 is input to the buzzer module 10 through the second switch tube Q2, so that the buzzer module 10 is powered on.

[0038] Further, refer to Figure 2The second switch unit 32 also includes a second current limiting resistor R5, the second switch tube Q2 is a PNP transistor, the input end of the second switch tube Q2 is the emitter of the PNP transistor, the output end is the collector of the PNP transistor, and the control end 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 a specific implementation, the second switch unit 32 also includes a second current limiting resistor R5. The second switch tube Q2 is designed using a PNP transistor. The input end, output end, and control end of the second switch tube 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 passes 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 to break through the PN junction of the PNP transistor. The emitter of the PNP transistor is connected to the input end of the buzzer module 10. In practical applications, the conduction condition of the PNP transistor is that the emitter voltage is greater than the base voltage. Therefore, when the second end of the bootstrap capacitor C1 does not generate a voltage multiple of the power supply 20, the emitter voltage and the base voltage of the transistor are equal to VCC. At this time, the PNP transistor is cut off. After the second end of the bootstrap capacitor C1 generates a voltage multiple of the power supply 20, the emitter voltage of the transistor is greater than the base voltage. At this time, the PNP transistor is turned on, so that the second end of the bootstrap capacitor C1 generates a voltage multiple of the power supply 20, which can be input to the driving buzzer module 10 to drive it to work and make sound.

[0039] In one embodiment, referring to Figure 2 , the voltage doubling module 30 also includes a discharge unit 34, the buzzer module 10 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 switch tube Q2, the second input terminal is grounded, and 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 doubling module 30 also includes a discharge unit 34, and the discharge unit 34 is specifically designed with a resistor or other load device with fast power consumption. The buzzer module 10 is provided with a first input terminal and a second input terminal, and the first input terminal and the second input terminal are specifically the positive and negative input terminals of the buzzer module 10, such as Figure 2As shown, c and d are used to represent the first input terminal and the second input terminal of the buzzer module 10. The first input terminal of the buzzer module 10 is connected to the output terminal of the second switch tube Q2, and the second input terminal of the buzzer module 10 is grounded. The discharge unit 34 is connected to the first input terminal and the second input terminal of the buzzer module 10. In practical applications, when the pulse signal source 21 changes from signal output to no signal output, that is, when the level signal output by the pulse signal source 21 disappears, the voltage at the second end of the bootstrap capacitor C1 passes through the buzzer module 10 and the discharge unit 34 to the ground. The discharge unit 34 consumes electrical energy to discharge the bootstrap capacitor C1 quickly, which can effectively prevent voltage superposition caused by powering on the subsequent circuit.

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

[0041] In one embodiment, in order to more clearly understand the working principle of the buzzer voltage doubling driving circuit, Figure 2 To illustrate the specific operation process of the buzzer voltage doubler drive circuit.

[0042] See also Figure 2 , VCC represents the power supply, V1 represents the pulse signal source, and 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 V1 has no output signal or the voltage at VCC is zero, transistors Q1 and Q2 are cut off, 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 at a high level, transistor Q1 is turned on, and the a-end of capacitor C1 is grounded as transistor Q1 is turned on. Therefore, the potential of the a-end of capacitor C1 is pulled down, that is, the a-end is at a low level, and the b-end of capacitor C1 is connected to VCC through diode D1. The potential of the b-end is pulled up, so the potential of the b-end is approximately equal to VCC, and the b-end of capacitor C1 is at a high level; at this time, there is a potential difference between the a-end and the b-end of capacitor C1, and capacitor C1 is charged; and the transistor The base of transistor Q2 is connected to VCC through resistor R5, and the base potential of transistor Q2 is pulled up, so the base voltage of transistor Q2 is VCC, and the emitter of transistor Q2 is connected to the b end of capacitor C1, so the emitter voltage of transistor Q2 is also VCC. Transistor Q2 is a PNP transistor, which will be turned on only when its emitter voltage is greater than the 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 a high level to a low level, transistor Q1 is cut off, and the a-end of capacitor C1 is connected to the power supply VCC through resistor R1. The potential of the a-end of capacitor C1 is pulled up, so the potential of the a-end of capacitor C1 is VCC; since the voltage across capacitor C1 cannot change suddenly, the potential of the b-end of capacitor C1 is superimposed on the potential of the a-end to be VCC+VCC=2VCC; 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 at the pull-up potential VCC, and at this time the potential of the emitter of transistor Q2 is equal to that of capacitor C1. The b-end potential is 2VCC, the transistor Q2 is turned on, and the b-end voltage of the capacitor C1 is input to the buzzer module U3, so that the buzzer module U3 is powered on and works. At this time, the driving voltage of the buzzer module U3 is the b-end voltage of the capacitor C1 2VCC, that is, the driving voltage of the buzzer module U3 is twice the voltage of the power supply VCC. Under the condition that the power supply VCC voltage is sufficient, the buzzer module U3 has a loud sound volume and good sound quality. Under the condition that the power supply VCC voltage is low, the power supply VCC voltage is lower than the minimum driving voltage of the buzzer module U3 within a certain range, and the buzzer module U3 can sound normally.

[0046] (4) When V1 changes from signal output to no signal output, the pulse signal source stops outputting signals. The voltage at terminal b of capacitor C1 passes through buzzer module U3 and resistor R2 to ground. Resistor R2 quickly consumes electrical energy, causing capacitor C1 to discharge quickly, preventing voltage superposition caused by powering on subsequent circuits.

[0047] Through this embodiment, when the power supply voltage is sufficient, the buzzer module can be guaranteed to have a loud sound volume and good sound quality. Under the condition of low power supply voltage, the buzzer module can also make normal sound to meet working requirements.

[0048] In one embodiment, an electronic device is provided, the electronic device includes the buzzer voltage doubling driving circuit described in the above embodiment, the electronic device is mainly powered by a battery, and can specifically be a device using a buzzer, such as a smoke alarm, a metal detector, an electronic toy, etc., the buzzer voltage doubling driving circuit is integrated in the electronic device, and is used to drive the buzzer to work and make sounds. Since the specific structure and working principle of the buzzer voltage doubling driving circuit have been described in detail in the previous specification, they will not be repeated here for the sake of brevity of the specification.

[0049] The electronic device in this embodiment adopts the buzzer voltage doubling driving circuit provided by the present invention, so the buzzer can sound normally under the condition of low power supply voltage, and the device can work effectively for a longer time under low voltage conditions.

[0050] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A buzzer voltage doubling driving circuit, characterized in that: include: Buzzer module, used for making sounds; A voltage doubling module, comprising a first switch unit, a second switch unit and a charging unit, wherein the charging unit is connected to a power source, the first switch unit is connected to the charging unit, and the second switch unit is connected to the power source, the charging unit and the buzzer module; Among them, the first switch unit is controlled to be on and off by a pulse signal source. When the first switch 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 switch unit to be turned on and then drives the buzzer module to make a sound.

2. The buzzer voltage doubling driving circuit according to claim 1, characterized in that: 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 switch unit and one end of the pull-up resistor, the second end of the bootstrap capacitor is connected to the second switch unit and the power supply, and the other end of the pull-up resistor is connected to the power supply, wherein the first switch unit is turned on to ground the first end of the bootstrap capacitor.

3. The buzzer voltage doubling driving circuit according to claim 2, characterized in that: The charging unit further includes a first diode, a cathode of the first diode is connected to the second end of the bootstrap capacitor and the second switch unit, and an anode of the first diode is connected to the power supply.

4. The buzzer voltage doubling driving circuit according to claim 3, characterized in that: The first switch unit includes a first switch tube, which is provided with an input end, an output end and a control end. The control end of the first switch tube is connected to the pulse signal source, the input end of the first switch tube is connected to the first end of the bootstrap capacitor, and the output end of the first switch tube is grounded.

5. The buzzer voltage doubling driving circuit according to claim 4, characterized in that: The first switching unit also includes a first current limiting resistor, the first switching tube is an NPN transistor, the input end of the first switching tube is the collector of the NPN transistor, the output end is the emitter of the NPN transistor, the control end 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.

6. The buzzer voltage doubling driving circuit according to any one of claims 3 to 5, characterized in that: The second switch unit includes a second switch tube, which is provided with an input end, an output end and a control end. The control end of the second switch tube is connected to the anode of the first diode and the power supply, the input end is connected to the second end of the bootstrap capacitor and the cathode of the first diode, and the output end is connected to the buzzer module. The input end voltage of the second switch tube is greater than the control end voltage to turn on the second switch tube.

7. The buzzer voltage doubling driving circuit according to claim 6, characterized in that: The second switch unit also includes a second current limiting resistor, the second switch tube is a PNP transistor, the input end of the second switch tube is the emitter of the PNP transistor, the output end is the collector of the PNP transistor, the control end 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.

8. The buzzer voltage doubling driving circuit according to claim 6, characterized in that: The voltage doubling module also 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 switch tube, and the second input terminal is grounded. The discharge unit is connected to the first input terminal and the second input terminal, wherein the discharge unit is used to discharge the bootstrap capacitor.

9. The buzzer voltage doubling driving circuit according to claim 8, characterized in that: The discharge unit includes a first resistor, one end of the first resistor is connected to the first input end, and the other end of the first resistor is connected to the second input end.

10. An electronic device, characterized in that: The buzzer voltage doubling driving circuit comprises the buzzer voltage doubling driving circuit as described in any one of claims 1 to 9.

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