CN113395004A

CN113395004A - Drive circuit and speaker system

Info

Publication number: CN113395004A
Application number: CN202110737665.0A
Authority: CN
Inventors: 周建成; 钱成锦
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2021-09-14

Abstract

The embodiment of the application relates to a drive circuit and a loudspeaker system, the drive circuit comprises: the power supply unit is used for providing a first voltage, a second voltage and a third voltage, wherein the second voltage is greater than the first voltage and less than the third voltage; the first switch unit is connected with the power supply unit and used for respectively receiving the first voltage, the second voltage and the third voltage and selectively outputting one of the first voltage, the second voltage and the third voltage under the control of a control signal; the second switch unit is connected with the power supply unit and used for respectively receiving the first voltage and the third voltage and selectively outputting one of the first voltage and the third voltage under the control of a control signal; wherein a voltage difference between the voltage output by the first switching unit and the voltage output by the second switching unit is used as an output voltage of the driving circuit.

Description

Drive circuit and speaker system

Technical Field

The embodiment of the application relates to the technical field of speakers, in particular to a driving circuit and a speaker system.

Background

With the development of mobile terminals such as smart phones, board-level density is also becoming more dense, and the requirements for audio performance are becoming higher and higher. An audio amplifier is required to reproduce a sound signal with a certain power on a speaker in a real and efficient manner, and the frequency range of the sound signal is about 20Hz to 20kHz, so that the amplifier must have a good frequency response in the frequency range. In order to reduce harmonic distortion of the speaker system, a large number of circuit elements need to be arranged in a driving circuit of the speaker, but this also results in a complicated structure of the driving circuit, which greatly limits the application of the speaker system in a small-sized mobile terminal.

Disclosure of Invention

The embodiment of the application provides a driving circuit and a loudspeaker system, which can optimize the number of elements in the driving circuit and simplify the structure of the driving circuit.

A drive circuit, comprising:

the power supply unit is used for providing a first voltage, a second voltage and a third voltage, wherein the second voltage is greater than the first voltage and less than the third voltage;

the first switch unit is connected with the power supply unit and used for respectively receiving the first voltage, the second voltage and the third voltage and selectively outputting one of the first voltage, the second voltage and the third voltage under the control of a control signal;

the second switch unit is connected with the power supply unit and used for respectively receiving the first voltage and the third voltage and selectively outputting one of the first voltage and the third voltage under the control of a control signal;

wherein a voltage difference between the voltage output by the first switching unit and the voltage output by the second switching unit is used as an output voltage of the driving circuit.

A speaker system comprising:

the loudspeaker comprises two driving ends, wherein the driving ends are used for receiving voltage so as to control the loudspeaker to play audio;

the first driving circuit adopts the driving circuit;

a second drive circuit using the drive circuit described above;

the control circuit is respectively connected with the first drive circuit and the second drive circuit and is used for respectively controlling the on-off of each first switch unit and each second switch unit;

the driving circuit is configured with a first power supply end and a second power supply end, the first power supply end is used for outputting one of the first voltage, the second voltage and the third voltage, the second power supply end is used for outputting one of the first voltage and the third voltage, the second power supply end of the first driving circuit is connected with the second power supply end of the second driving circuit, and the first power supply end of the first driving circuit and the first power supply end of the second driving circuit are respectively connected with the two driving ends of the loudspeaker in a one-to-one correspondence manner.

The above-mentioned drive circuit and speaker system, the drive circuit includes: the power supply unit is used for providing a first voltage, a second voltage and a third voltage, wherein the second voltage is greater than the first voltage and less than the third voltage; the first switch unit is connected with the power supply unit and used for respectively receiving the first voltage, the second voltage and the third voltage and selectively outputting one of the first voltage, the second voltage and the third voltage under the control of a control signal; the second switch unit is connected with the power supply unit and used for respectively receiving the first voltage and the third voltage and selectively outputting one of the first voltage and the third voltage under the control of a control signal; wherein a voltage difference between the voltage output by the first switching unit and the voltage output by the second switching unit is used as an output voltage of the driving circuit. In the embodiment of the present application, the five-level output of the driving circuit may be realized based on the first switching unit having the three-level output function and the second switching unit having the two-level output function. On the premise that the amplitude of the output voltage is not changed, by setting a larger number of intermediate level output states, the harmonic content in the output voltage of the driving circuit can be reduced, and high-quality audio playing of the loudspeaker is realized. Meanwhile, the first switch unit and the second switch unit which are in asymmetric structures are arranged, so that the number of switch elements in the driving circuit can be reduced, and the driving circuit with fewer devices and simpler circuit is provided.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or related technologies of the present application, the drawings needed to be used in the description of the embodiments or related technologies are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a block diagram of a driving circuit according to an embodiment;

FIG. 2 is a waveform diagram of a five-level output;

FIG. 3 is a voltage harmonic plot of a three-level output of an embodiment;

FIG. 4 is a voltage harmonic plot of a five level output of an embodiment;

FIG. 5 is a circuit diagram of a driving circuit according to an embodiment;

FIG. 6 is a state diagram of a switching device of the driving circuit of the embodiment of FIG. 5 in a first operation mode;

FIG. 7 is a state diagram of a switching device of the driving circuit of the embodiment of FIG. 5 in a second operation mode;

FIG. 8 is a state diagram of a switching device of the driving circuit of the embodiment of FIG. 5 in a third operating mode;

FIG. 9 is a state diagram of a switching device of the driving circuit of the embodiment of FIG. 5 in a fourth operating mode;

FIG. 10 is a state diagram of a switching device of the driving circuit of the embodiment of FIG. 5 in a fifth operating mode;

FIG. 11 is a second circuit diagram of a driving circuit according to an embodiment;

FIG. 12 is a second schematic diagram of a driving circuit according to an embodiment;

FIG. 13 is a third circuit diagram of a driving circuit according to an embodiment;

FIG. 14 is a fourth circuit diagram of a driving circuit according to an embodiment;

FIG. 15 is a block diagram of a speaker system according to an embodiment;

FIG. 16 is a fifth circuit diagram of a driving circuit according to an embodiment;

fig. 17 is a second block diagram of the speaker system according to the embodiment.

Element number description:

a drive circuit: 10; a power supply unit: 100, respectively; a first power supply component: 110; a second power supply assembly: 120 of a solvent; a first switching unit: 200 of a carrier; a protection circuit: 210; a second switching unit: 300, respectively; the first drive circuit: 11; a second drive circuit: 12; a loudspeaker: 20; the control circuit: 30, of a nitrogen-containing gas; a gain circuit: 31; PWM comparator circuit: 32.

Detailed Description

To facilitate an understanding of the embodiments of the present application, the embodiments of the present application will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present application are shown in the drawings. The embodiments of the present application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this application belong. The terminology used herein in the description of the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of the present application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first voltage may be referred to as a second voltage, and similarly, a second voltage may be referred to as a first voltage, without departing from the scope of the present application. The first voltage and the second voltage are both voltages, but they are not the same voltage.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise. In the description of the present application, "a number" means at least one, such as one, two, etc., unless specifically limited otherwise.

Fig. 1 is a block diagram of a driving circuit 10 according to an embodiment, and referring to fig. 1, in the embodiment, the driving circuit 10 includes a power supply unit 100, a first switching unit 200, and a second switching unit 300.

The power supply unit 100 is configured to provide a first voltage, a second voltage and a third voltage, wherein the second voltage is greater than the first voltage and less than the third voltage. The difference between the first voltage and the second voltage may be equal to the difference between the second voltage and the second voltage, or may not be equal to the difference between the second voltage and the third voltage, which is not limited in this embodiment.

The first switching unit 200 is connected to the power supply unit 100, and configured to receive the first voltage, the second voltage, and the third voltage, respectively, and selectively output one of the first voltage, the second voltage, and the third voltage under the control of a control signal. The control signal may include a signal, and the first switching unit 200 selectively outputs a voltage according to the received signal. The control signal may also include a plurality of signals, and the plurality of signals collectively control the first switching unit 200 to selectively output one voltage. It will be appreciated that the control signal corresponds to the audio to be played, thereby achieving accurate driving of the speaker.

The second switching unit 300 is connected to the power supply unit 100, and is configured to receive the first voltage and the third voltage, respectively, and selectively output one of the first voltage and the third voltage under the control of a control signal. Wherein, a voltage difference between the voltage output by the first switching unit 200 and the voltage output by the second switching unit 300 is used as the output voltage of the driving circuit 10.

Specifically, based on the first switching unit 200 being capable of outputting one of the first voltage U1, the second voltage U2, and the third voltage U3, and the second switching unit 300 being capable of outputting one of the first voltage U1 and the third voltage U3, the voltage differences may include U1-U3, U2-U1, U2-U3, U3-U1, and 0. Therefore, the drive circuit 10 of the present embodiment is capable of outputting five different voltage values, that is, five-level output of the drive circuit 10 is realized.

Fig. 2 is a schematic diagram of a waveform of a five-level output, and referring to fig. 2, the driving circuit can excite the speaker to vibrate continuously by outputting a driving voltage signal with a continuously changing voltage value, so as to play audio. It can be understood that, the more the number of levels that the driving module can output, the more gradual the driving circuit is in switching the output voltage, the closer the overall waveform of the driving voltage signal is to a sine wave, i.e., the less harmonic content is output. Specifically, fig. 3 is a voltage Harmonic graph of a three-level output of an embodiment, and fig. 4 is a voltage Harmonic graph of a five-level output of an embodiment, with reference to fig. 3 and 4, where THD (Total Harmonic Distortion), i.e., the Total Harmonic Distortion, is used to evaluate the Harmonic content in the signal, as shown, the THD at the three-level output is about 87.86%, and the THD at the five-level output is about 42.45%. That is, the harmonic content in the driving voltage signal at the time of the five-level output is much smaller than the harmonic content in the driving voltage signal at the time of the three-level output. It can be understood that the harmonic content directly affects the distortion of the played audio signal, and the smaller the harmonic content is, the smaller the distortion of the audio signal is, and the higher the playing quality is.

In the present embodiment, by providing the first switch unit 200 and the second switch unit 300 having different structures, different numbers of switch elements can be provided in the first switch unit 200 and the second switch unit 300, respectively, as needed. Therefore, the five-level output with smaller harmonic content is realized, and the number of switching elements in the driving circuit can be reduced, so that the driving circuit with fewer devices and simpler circuit is provided. It is understood that the driving circuit of the present embodiment may be directly connected to a speaker to realize a five-level driving speaker system. The driving circuit of this embodiment may also be connected to other devices except the speaker to implement a speaker system with richer functions or higher audio playing quality, which is not limited in this embodiment.

In one embodiment, the first switch unit 200 is configured with three first input terminals for receiving the first voltage, the second voltage and the third voltage in a one-to-one correspondence, and a first output terminal for outputting one of the first voltage, the second voltage and the third voltage, transmission paths are formed between the first input terminals and the first output terminal, and the first switch unit 200 is configured to selectively turn on one of the three transmission paths under the control of a control signal. In this embodiment, the first switch unit 200 can be understood as a multi-way switch with one-out-of-multiple function, and can perform corresponding path switching according to the control signal. The multiplexer switch may only include a data selector (MUX) chip packaged independently, or a plurality of devices may form a multiplexer switch together to adjust the performance and the control method thereof more flexibly, which is not limited in this embodiment.

Fig. 5 is one of the circuit diagrams of the driving circuit of an embodiment, and referring to fig. 5, in one embodiment, the first voltage may be 0V, and the third voltage is 2 times the second voltage, that is, the second voltage is Udc, and the third voltage is 2 Udc. With continued reference to fig. 5, in one embodiment, the first voltage 0V, the second voltage Udc and the third voltage 2Udc may be implemented using voltage doubling circuits. Specifically, the power supply unit 100 includes a first capacitor C1 and a second capacitor C2 connected in series. The common terminal of the first capacitor C1 and the second capacitor C2 is used for receiving the second voltage Udc input from the outside and outputting the second voltage Udc. The other end of the first capacitor C1 is used for outputting the third voltage 2Udc, and the other end of the second capacitor C2 is used for outputting the first voltage 0V. One end of the second capacitor C2 for outputting the first voltage 0V may be connected to the ground terminal. In other embodiments, the first voltage 0V, the second voltage Udc and the third voltage 2Udc may be implemented by using a half-voltage circuit, and specifically, the voltage of 2Udc may be input to the power supply unit 100, and Udc may be generated by means of resistance voltage division. The first voltage 0V, the second voltage Udc and the third voltage 2Udc may also be provided directly by means of a dc voltage source. In the following embodiments, the power supply unit 100 is described by using a voltage doubler circuit as an example.

With continued reference to fig. 5, in one embodiment, the control signals include a first control signal, a second control signal, and a third control signal, and the first switching unit 200 includes a first switching device S1, a second switching device S2, and a third switching device S3.

A first terminal of the first switching device S1 is configured to receive the third voltage 2Udc, a second terminal of the first switching device S1 is connected to the first output terminal, a control terminal of the first switching device S1 is configured to receive a first control signal, and the first control signal is configured to control on/off of the first switching device S1. A first terminal of the second switching device S2 is configured to receive the first voltage 0V, a second terminal of the second switching device S2 is connected to the first output terminal, a control terminal of the second switching device S2 is configured to receive a second control signal, and the second control signal is configured to control on/off of the second switching device S2. A first terminal of the third switching device S3 is configured to receive the second voltage Udc, a second terminal of the third switching device S3 is connected to the first output terminal, and a control terminal of the third switching device S3 is configured to receive a third control signal, and the third control signal is configured to control on/off of the third switching device S3. Wherein, at the same time, one of the first switching device S1, the second switching device S2, and the third switching device S3 is turned on.

In the present embodiment, by respectively controlling the on-off states of the first switching device S1, the second switching device S2, and the third switching device S3, the first output terminal of the first switching unit 200 can be made to accurately output one of the first voltage 0V, the second voltage Udc, and the third voltage 2Udc at any one time. In addition, by switching the on/off states of the first switching device S1, the second switching device S2, and the third switching device S3, the voltage output by the first output terminal can be changed, so that the output voltage of the driving circuit is continuously changed, and continuous excitation of the speaker is realized.

Optionally, each of the switching devices may be one or more of a triode, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), and an Insulated Gate Bipolar Transistor (IGBT). The types of the respective switching devices may be the same or different. In the present embodiment, for simplicity of explanation, each switching device in the first switching unit 200 is respectively referred to as a switch S1 through a switch S3 in the drawings of the present embodiment.

In one embodiment, with continued reference to fig. 5, the second switching unit 300 is configured with a second output terminal for outputting one of the first voltage 0V and the third voltage 2Udc, the second switching unit 300 comprising a fourth switching device S4 and a fifth switching device S5.

A first terminal of the fourth switching device S4 is configured to receive the third voltage 2Udc, a second terminal of the fourth switching device S4 is connected to the second output terminal, a control terminal of the fourth switching device S4 is configured to receive a fourth control signal, and the fourth control signal is configured to control on/off of the fourth switching device S4. A first terminal of the fifth switching device S5 is configured to receive the first voltage 0V, a second terminal of the fifth switching device S5 is connected to the second output terminal, a control terminal of the fifth switching device S5 is configured to receive a fifth control signal, and the fifth control signal is configured to control on/off of the fifth switching device S5. Wherein, at the same time, one of the fourth switching device S4 and the fifth switching device S5 is turned on. In the present embodiment, for simplicity of explanation, the switching devices in the second switching unit 300 are respectively referred to as switches S4 to S5.

In the present embodiment, by respectively controlling the on-off states of the fourth switching device S4 and the fifth switching device S5, at any one time, the second output terminal of the second switching unit 300 can be made to accurately output one of the first voltage 0V and the third voltage 2 Udc. In addition, by switching the on/off states of the fourth switching device S4 and the fifth switching device S5, the voltage output by the second output terminal can be changed, so that the output voltage of the driving circuit is continuously changed, and the continuous excitation of the speaker is realized. That is, in the embodiment shown in fig. 5, the second switching device S2 and the fifth switching device S5 are used to control the conduction and the disconnection of the transmission path of the first voltage 0V, the third switching device S3 is used to control the conduction and the disconnection of the transmission path of the second voltage Udc, and the first switching device S1 and the fourth switching device S4 are used to control the conduction and the disconnection of the transmission path of the third voltage 2 Udc.

It should be noted that although the same fig. 5 is used to show the specific structure of the first switch unit 200 and the second switch unit 300 of different embodiments, the types of the components inside the first switch unit 200 and the second switch unit 300 may be different. For example, each switching device in the first switching unit 200 may be a triode, and each switching device in the second switching unit 300 may be a MOS transistor, which is not limited in this embodiment.

Based on the driving circuit of the embodiment of fig. 5, the manner of generating each output voltage is specifically described below. Specifically, the drive circuit is configured with five different operation modes, each preset with the on-off state of the corresponding switching device. In each working mode, the driving circuit outputs corresponding voltage respectively, and can realize the switching of the on-off state of the switch device by changing the control signal mode, thereby changing the voltage output by the driving circuit.

Specifically, fig. 6 is a schematic diagram of states of the switching devices of the driving circuit in the first operation mode of the embodiment of fig. 5, and referring to fig. 6, in the first operation mode, the first switching device S1 and the fifth switching device S5 are turned on, the first output terminal outputs the third voltage 2Udc, the second output terminal outputs the first voltage 0V, and the output voltage of the driving circuit is the difference 2Udc between the two voltages. Fig. 7 is a schematic diagram illustrating states of the switching devices of the driving circuit in the second operation mode of the embodiment in fig. 5, and referring to fig. 7, in the second operation mode, the third switching device S3 and the fifth switching device S5 are turned on, the first output terminal outputs the second voltage Udc, the second output terminal outputs the first voltage 0V, and the output voltage of the driving circuit is the difference Udc between the two voltages. Fig. 8 is a state diagram of the switching devices of the driving circuit of the embodiment of fig. 5 in the third operation mode, and referring to fig. 8, in the third operation mode, the first switching device S1 and the fourth switching device S4 are turned on, the first output terminal outputs the third voltage 2Udc, the second output terminal outputs the third voltage 2Udc, and the output voltage of the driving circuit is the difference 0 between the two voltages. Fig. 9 is a schematic diagram illustrating states of the switching devices of the driving circuit of fig. 5 in a fourth operation mode, and referring to fig. 9, in the fourth operation mode, the third switching device S3 and the fourth switching device S4 are turned on, the first output terminal outputs the second voltage Udc, the second output terminal outputs the third voltage 2Udc, and the output voltage of the driving circuit is the difference-Udc between the two voltages. Fig. 10 is a schematic diagram illustrating states of the switching devices of the driving circuit of the embodiment of fig. 5 in a fifth operating mode, and referring to fig. 10, in the fifth operating mode, the second switching device S2 and the fourth switching device S4 are turned on, the first output terminal outputs a first voltage 0V, the second output terminal outputs a third voltage 2Udc, and an output voltage of the driving circuit is a difference-2 Udc between the two voltages. As can be seen from fig. 6 to fig. 10, with the control method of the present embodiment, the switching of the adjacent operating modes can be realized by changing the on-off states of a small number of switching devices, so as to reduce the power consumption of the switching devices, and further realize a driving circuit with lower power consumption.

Fig. 11 is a second circuit diagram of the driving circuit according to an embodiment, and referring to fig. 11, in the embodiment, each switching device is a MOS transistor. Specifically, the drain of the first MOS transistor T1 is configured to receive the third voltage 2Udc, the source of the first MOS transistor T1 is connected to the first output terminal, the gate of the first MOS transistor T1 is configured to receive a first control signal, and the first control signal is configured to control on/off of the first MOS transistor T1. The source of the second MOS transistor T2 is configured to receive the first voltage 0V, the drain of the second MOS transistor T2 is connected to the first output terminal, the gate of the second MOS transistor T2 is configured to receive a second control signal, and the second control signal is configured to control on/off of the second MOS transistor T2. The drain of the third MOS transistor T3 is configured to receive the second voltage Udc, the source of the third MOS transistor T3 is connected to the first output terminal, the gate of the third MOS transistor T3 is configured to receive a third control signal, and the third control signal is configured to control on/off of the third MOS transistor T3. The drain of the fourth MOS transistor T4 is configured to receive the third voltage 2Udc, the source of the fourth MOS transistor T4 is connected to the second output terminal, the gate of the fourth MOS transistor T4 is configured to receive a fourth control signal, and the fourth control signal is configured to control on/off of the fourth MOS transistor T4. The source of the fifth MOS transistor T5 is configured to receive the first voltage 0V, the drain of the fifth MOS transistor T5 is connected to the second output terminal, the gate of the fifth MOS transistor T5 is configured to receive a fifth control signal, and the fifth control signal is configured to control on/off of the fifth MOS transistor T5. In this embodiment, the MOS transistor with a fast response speed is used as the switching element, so that the output response speed of the driving circuit can be greatly increased, and the driving circuit can be applied to a mobile terminal with a high requirement on audio quality.

In one embodiment, the fourth control signal and the fifth control signal are the same signal, and the control logic of the fourth switching device S4 and the fifth switching device S5 is opposite, wherein the control logic includes high level conduction and low level conduction. Specifically, in the embodiment shown in fig. 11, the fourth MOS transistor T4 is a P-type MOS transistor turned on at a low level, the fifth MOS transistor T5 is an N-type MOS transistor turned on at a high level, and the fourth switching device S4 and the fifth switching device S5 are controlled by the same control signal, so that the fourth switching device S4 and the fifth switching device S5 are not turned on at the same time, and thus the number of control signals is reduced, and the control logic of the driving circuit is simplified.

Fig. 12 is a second schematic structural diagram of the driving circuit of an embodiment, and referring to fig. 12, in this embodiment, the first switching unit 200 further includes a protection circuit 210, the protection circuit 210 is respectively connected to the power supply unit 100 and the third switching device S3, a first end of the third switching device S3 receives the second voltage Udc through the protection circuit 210, and a first end of the third switching device S3 outputs the second voltage Udc through the protection circuit 210. In this embodiment, by providing the protection circuit 210, the problem of damage caused by an excessively large source-drain voltage difference of the third MOS transistor T3 can be avoided, so that the reliability of the third MOS transistor T3 is improved, and the reliability of the driving circuit is further improved.

Fig. 13 is a third circuit diagram of a driving circuit according to an embodiment, and referring to fig. 13, in the embodiment, the protection circuit 210 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. Wherein an anode of the first diode D1 is connected with a cathode of the third diode D3, and a cathode of the first diode D1 is connected with a cathode of the second diode D2. An anode of the fourth diode D4 is connected to an anode of the third diode D3, and a cathode of the fourth diode D4 is connected to an anode of the second diode D2. A first terminal of the third switching device S3 is connected to a cathode of the first diode D1, a second terminal of the third switching device S3 is connected to an anode of a fourth transistor, an anode of the first diode D1 is configured to receive the second voltage Udc, and a cathode of the fourth diode D4 is configured to output the second voltage Udc when the third switching device S3 is turned on. In this embodiment, by providing the plurality of diodes, based on the unidirectional conduction characteristic of the diodes, the source-drain voltage difference of the third MOS transistor T3 may be prevented from being too large, so as to protect the third MOS transistor T3.

Fig. 14 is a fourth circuit diagram of the driving circuit according to an embodiment, and referring to fig. 14, in this embodiment, the control signal further includes a sixth control signal, and the first switching unit 200 further includes a sixth switching device S6. A first terminal of the sixth switching device S6 is connected to the first output terminal, a second terminal of the sixth switching device S6 is configured to receive the second voltage Udc, a control terminal of the sixth switching device S6 is configured to receive a sixth control signal, and the sixth control signal is configured to control on/off of the sixth switching device S6. In the embodiment shown in fig. 14, the sixth switching device S6 may be a sixth MOS transistor T6, that is, the drain of the sixth MOS transistor T6 is connected to the first output terminal, the source of the sixth MOS transistor T6 is configured to receive the second voltage Udc, and the gate of the sixth MOS transistor T6 is configured to receive a sixth control signal. In the present embodiment, by providing the sixth switching device S6, it is possible to improve the control accuracy of the transmission path of the second voltage Udc, thereby improving the accuracy of the output voltage of the drive circuit.

Based on the aforementioned drive circuit, this application still provides a speaker system. Specifically, this embodiment is explained based on the driving circuit of the embodiment of fig. 13 as an example, fig. 15 is one of the structural block diagrams of the speaker system of the embodiment, and referring to fig. 13, in this embodiment, the speaker system includes a speaker 20, a first driving circuit 11, a second driving circuit 12, and a control circuit 30.

The speaker 20 includes two driving terminals, and the driving terminals are used for receiving the voltages output by the first driving circuit 11 and the second driving circuit 12 to control the speaker 20 to play audio. The control circuit 30 is respectively connected to the first driving circuit 11 and the second driving circuit 12, and is configured to respectively control on/off of each of the first switch units 200 and each of the second switch units 300.

The above-described drive circuit 10 is used for the first drive circuit 11, and the above-described drive circuit 10 may be used for the second drive circuit 12. The first drive circuit 11 and the second drive circuit 12 may have different configurations, and for example, the drive circuit 10 according to the embodiment of fig. 13 is used for the first drive circuit 11, and the drive circuit 10 according to the embodiment of fig. 14 is used for the second drive circuit 12. Wherein the driving circuit 10 is configured with a first power supply terminal for outputting one of the first voltage 0V, the second voltage Udc and the third voltage 2Udc and a second power supply terminal for outputting one of the first voltage 0V and the third voltage 2Udc, the second power supply terminal of the first driving circuit 11 is connected with the second power supply terminal of the second driving circuit 12, and the first power supply terminal of the first driving circuit 11 and the first power supply terminal of the second driving circuit 12 are respectively connected with two driving terminals of the speaker 20 in a one-to-one correspondence manner. In the present embodiment, based on the aforementioned driving circuit 10, the first driving circuit 11 and the second driving circuit 12 can be enabled to jointly realize nine-level output by connecting the second power supply terminal of the first driving circuit 11 and the second power supply terminal of the second driving circuit 12, that is, nine levels include 4Udc, 3Udc, 2Udc, 0, -Udc, -2Udc, -3Udc, -4 Udc. Similarly to the foregoing embodiment, by increasing the number of output levels, the overall waveform of the driving voltage signal received by the speaker 20 can be made closer to a sine wave, so as to further reduce the harmonic content in the driving voltage signal, thereby improving the audio playing quality of the speaker 20.

With continued reference to fig. 15, in one embodiment, the control circuit 30 includes a gain circuit 31 and a PWM comparator circuit 32. The gain circuit 31 is configured to receive an initial audio signal and amplify the initial audio signal to generate an analog audio signal. It is understood that the specific structure of the gain circuit 31 is not limited in this embodiment, and a circuit structure capable of implementing a signal amplification function is within the protection scope of this embodiment. The PWM comparator circuit 32 is connected to the gain circuit 31, the first driving circuit 11, and the second driving circuit 12, and configured to generate a plurality of corresponding pulse control signals according to an analog audio signal, where each pulse control signal is used to control on/off of each first switch unit and each second switch unit in a one-to-one correspondence manner, so as to control the speaker 20 to play an audio corresponding to the analog audio signal. Specifically, in the embodiment of fig. 15, the gates of the MOS transistors may respectively receive different pulse control signals to respectively control the on-off states of the MOS transistors.

Further, the PWM comparator circuit 32 includes a clock oscillator module and a PWM module. The clock oscillator module is configured to provide a carrier signal, and the input analog audio signal and its inverse signal are simultaneously compared with a triangular wave in the PWM module to generate two different pulse control signals, where the two different pulse control signals are respectively used to control the first driving circuit 11 and the second driving circuit 12, so that the first driving circuit 11 and the second driving circuit 12 generate output voltages with opposite voltage values, and finally are loaded on the two driving terminals of the speaker 20, and the output voltages are demodulated by the speaker 20 to generate sound with corresponding frequencies.

Fig. 16 is a fifth circuit diagram of a driving circuit according to an embodiment, and referring to fig. 16, in this embodiment, the power supply unit 100 includes a first power supply component 110 and a second power supply component 120. The first power supply assembly 110 is connected to said first switching unit 200 for providing said first switching unit 200 with said first voltage 0V, said second voltage Udc and said third voltage 2 Udc. The second power supply assembly 120 is connected to said second switching unit 300 for providing said second switching unit 300 with said first voltage 0V and said third voltage 2 Udc. Compared with the driving circuit with a symmetrical structure in the related art, the present embodiment can also enable the driving circuit to output five levels of-2 Udc, -Udc, 0, Udc and 2Udc by adopting the asymmetrical first switching unit 200 and the second switching unit 300 and enabling the second switching unit 300 to output only the bi-level voltage. The second switch unit 300 only needs to include two switch devices, and the two-level output can be realized by combining corresponding control signals, that is, the present embodiment provides a driving circuit with a small number of devices and a simple circuit.

Based on the driving circuit 10 of the embodiment of fig. 16, the present application further provides a speaker system, fig. 17 is a second block diagram of the structure of the speaker system of the embodiment, and referring to fig. 17, in the present embodiment, the speaker system includes a speaker 20, the driving circuit 10, and a control circuit 30.

The speaker 20 includes two driving terminals for receiving a voltage to control the speaker 20 to play audio. The driving circuit 10 adopts the driving circuit 10 as described above, and the driving circuit 10 is configured with a first power supply terminal for outputting one of the first voltage 0V, the second voltage Udc and the third voltage 2Udc and a second power supply terminal for outputting one of the first voltage 0V and the third voltage 2Udc, and the first power supply terminal and the second power supply terminal are respectively connected to two driving terminals of the speaker 20 in a one-to-one correspondence manner. The control circuit 30 is connected to the driving circuit 10 and configured to control on/off of the first switch unit and the second switch unit.

It is understood that the structure of the control circuit 30 of this embodiment can refer to the embodiment in fig. 15, and is not described herein again. This embodiment is implemented based on fig. 16, and provides a five-level output driver circuit 10 with a small number of devices and a simple circuit.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express a few embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for those skilled in the art, variations and modifications can be made without departing from the concept of the embodiments of the present application, and these embodiments are within the scope of the present application. Therefore, the protection scope of the embodiments of the present application shall be subject to the appended claims.

Claims

1. A driver circuit, comprising:

2. The driving circuit according to claim 1, wherein the first switching unit is configured with three first input terminals for receiving the first voltage, the second voltage, and the third voltage, respectively, in a one-to-one correspondence, and a first output terminal for outputting one of the first voltage, the second voltage, and the third voltage, a transmission path is formed between each of the first input terminals and the first output terminal, and the first switching unit is configured to selectively turn on one of the three transmission paths under control of a control signal.

3. The driving circuit according to claim 2, wherein the control signal includes a first control signal, a second control signal, and a third control signal, and the first switching unit includes:

a first end of the first switching device is used for receiving the third voltage, a second end of the first switching device is connected with the first output end, a control end of the first switching device is used for receiving a first control signal, and the first control signal is used for controlling the on-off of the first switching device;

a first end of the second switching device is used for receiving the first voltage, a second end of the second switching device is connected with the first output end, a control end of the second switching device is used for receiving a second control signal, and the second control signal is used for controlling the on-off of the second switching device;

a first end of the third switching device is used for receiving the second voltage, a second end of the third switching device is connected with the first output end, a control end of the third switching device is used for receiving a third control signal, and the third control signal is used for controlling the on-off of the third switching device;

wherein one of the first switching device, the second switching device, and the third switching device is turned on at the same time.

4. The driving circuit according to claim 3, wherein the first switching unit further includes a protection circuit, the protection circuit is connected to the power supply unit and the third switching device, respectively, a first end of the third switching device receives the second voltage through the protection circuit, and a first end of the third switching device outputs the second voltage through the protection circuit.

5. The drive circuit according to claim 4, wherein the protection circuit includes a first diode, a second diode, a third diode, and a fourth diode; wherein the content of the first and second substances,

the anode of the first diode is connected with the cathode of the third diode, and the cathode of the first diode is connected with the cathode of the second diode;

the anode of the fourth diode is connected with the anode of the third diode, and the cathode of the fourth diode is connected with the anode of the second diode;

wherein a first terminal of the third switching device is connected to a cathode of the first diode, a second terminal of the third switching device is connected to an anode of the fourth transistor, the anode of the first diode is configured to receive the second voltage, and the cathode of the fourth diode is configured to output the second voltage when the third switching device is turned on.

6. The driving circuit of claim 3, wherein the control signal further comprises a sixth control signal, and wherein the first switching unit further comprises:

a first end of the sixth switching device is connected with the first output end, a second end of the sixth switching device is used for receiving the second voltage, a control end of the sixth switching device is used for receiving a sixth control signal, and the sixth control signal is used for controlling the on-off of the sixth switching device.

7. The drive circuit according to claim 1, wherein the second switching unit is configured with a second output terminal for outputting one of the first voltage and the third voltage, the second switching unit comprising:

a first end of the fourth switching device is used for receiving the third voltage, a second end of the fourth switching device is connected with the second output end, a control end of the fourth switching device is used for receiving a fourth control signal, and the fourth control signal is used for controlling the on-off of the fourth switching device;

a fifth switching device, a first end of which is configured to receive the first voltage, a second end of which is connected to the second output end, a control end of which is configured to receive a fifth control signal, and the fifth control signal is configured to control on/off of the fifth switching device;

wherein one of the fourth switching device and the fifth switching device is turned on at the same time.

8. The driving circuit of claim 7, wherein the fourth control signal and the fifth control signal are the same signal, and the control logic of the fourth switching device and the fifth switching device is opposite, wherein the control logic comprises a high level conduction and a low level conduction.

9. The driving circuit according to any one of claims 1 to 8, wherein the first voltage is 0V and the third voltage is 2 times the second voltage.

10. The drive circuit according to claim 9, wherein the power supply unit includes: the first capacitor and the second capacitor are connected in series, and a common end connected with the first capacitor and the second capacitor is used for receiving the second voltage input from the outside and outputting the second voltage; the other end of the first capacitor is used for outputting the third voltage, and the other end of the second capacitor is used for outputting the first voltage.

11. A speaker system, comprising:

a first drive circuit using the drive circuit according to any one of claims 1 to 10;

a second drive circuit using the drive circuit according to any one of claims 1 to 10;

12. The speaker system of claim 11, wherein the control circuit comprises:

the gain circuit is used for receiving an initial audio signal and amplifying the initial audio signal to generate an analog audio signal;

and the PWM comparator circuit is respectively connected with the gain circuit, the first driving circuit and the second driving circuit and is used for generating a plurality of corresponding pulse control signals according to analog audio signals, and each pulse control signal is respectively used for controlling the on-off of each first switch unit and each second switch unit in a one-to-one correspondence manner so as to control the loudspeaker to play audio corresponding to the analog audio signals.