WO2019085427A1 - 音频播放电路以及音频播放设备 - Google Patents

音频播放电路以及音频播放设备 Download PDF

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Publication number
WO2019085427A1
WO2019085427A1 PCT/CN2018/085627 CN2018085627W WO2019085427A1 WO 2019085427 A1 WO2019085427 A1 WO 2019085427A1 CN 2018085627 W CN2018085627 W CN 2018085627W WO 2019085427 A1 WO2019085427 A1 WO 2019085427A1
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Prior art keywords
module
output
voltage
power
control
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Ceased
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PCT/CN2018/085627
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English (en)
French (fr)
Inventor
尹德杨
李君�
李定
杜帅
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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Priority to EP18874131.8A priority Critical patent/EP3675518B1/en
Publication of WO2019085427A1 publication Critical patent/WO2019085427A1/zh
Priority to US16/828,425 priority patent/US11139784B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/32—Modifications of amplifiers to reduce non-linear distortion
    • H03F1/3241—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits
    • H03F1/3264—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits in audio amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
    • H03F3/183—Low-frequency amplifiers, e.g. audio preamplifiers with semiconductor devices only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/02—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
    • H03F1/0205—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers
    • H03F1/0211—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers with control of the supply voltage or current
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
    • H03F1/305—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in case of switching on or off of a power supply
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/34—Muting amplifier when no signal is present
    • H03G3/348—Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers
    • H04R3/007—Protection circuits for transducers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/03—Indexing scheme relating to amplifiers the amplifier being designed for audio applications

Definitions

  • the present invention relates to the field of electronic power, and in particular to an audio playback circuit and an audio playback device.
  • the audio playback device When an audio playback device such as a speaker or a headphone is powered on, an unpleasant sound of " ⁇ " is often generated. This unpleasant sound is called a popping sound, and may also be called a pop sound or a noise.
  • the audio playback device generally includes an audio power amplifier circuit, a coupling capacitor and a load, and the audio power amplifier circuit connects the load through a coupling capacitor.
  • the output node of the audio power amplifier circuit is at an indefinite level close to 0.
  • the output node will instantly change from an indefinite level close to 0.
  • An indefinite level of a certain level (0 to an indefinite level between the single supply voltages)
  • the level of the output node rapidly changes from an indefinite level close to 0 to an indefinite level having a certain level.
  • a fast level change is possible by coupling the coupling capacitor to the load, which produces a popping sound.
  • the technical problem to be solved by the embodiments of the present invention is to provide an audio playing circuit and an audio playing device, which can suppress the popping sound generated by the audio playing device during the power-on of the power module.
  • a first aspect of the embodiments of the present invention provides an audio playback circuit, including a power module, a power amplifier, a coupling capacitor, a load, and a plosive suppression circuit, wherein:
  • An output end of the power amplifier is connected to a first end of the coupling capacitor and an output end of the plosive suppression circuit, a second end of the coupling capacitor is connected to the load, and an output end of the power module is connected to the a power supply end of the power amplifier and a power supply end of the plosive suppression circuit; the power supply module is configured to provide a DC supply voltage for the power amplifier and the plosive suppression circuit;
  • the plosive suppression circuit is configured to disconnect the first end of the coupling capacitor from the ground when the DC supply voltage is lower than the first voltage threshold, where the first voltage threshold is lower than the power amplifier Operating voltage threshold;
  • the plosive suppression circuit is further configured to connect the first end of the coupling capacitor to the ground end when the DC supply voltage rises to the first voltage threshold.
  • the load may be a speaker or a speaker
  • the operating voltage threshold of the plosive suppression circuit is a first voltage threshold lower than a working voltage threshold of the power amplifier.
  • the plosive suppression is performed.
  • the circuit begins to operate and grounds the output of the plosive suppression circuit to ground the first end of the coupling capacitor.
  • the first end of the coupling capacitor is grounded to prevent the power module from jumping horizontally at the output of the power amplifier during power-on, thereby preventing the level jump from being coupled to the load through the coupling capacitor.
  • a popping sound is generated to suppress the popping sound generated by the power module during power-on.
  • the audio playback circuit further includes a controller, where the plosive suppression circuit includes a reset module, a flip-flop, a capacitor resistance parallel module, a level inverter, and a first switch tube, and the output end of the reset module is connected.
  • the plosive suppression circuit includes a reset module, a flip-flop, a capacitor resistance parallel module, a level inverter, and a first switch tube, and the output end of the reset module is connected.
  • a reset end of the flip-flop an input end of the flip-flop is connected to a first control end of the controller, an output end of the flip-flop is connected to a first end of the capacitor resistance parallel module, and the level is inverted
  • the output end of the level inverter is connected to the control end of the first switch tube, and the first end of the first switch tube is connected to the output end of the power amplifier, the first switch tube
  • the second end of the capacitor resistance parallel module is connected to the ground end, and the operating voltage threshold of the level inverter is equal to the first voltage threshold;
  • An output end of the power module is connected to a power supply end of the controller, a power supply end of the reset module, a power supply end of the flip-flop, and a power supply end of the level inverter; the power module is used for Said reset module, said flip-flop and said level inverter providing said DC supply voltage;
  • the capacitor resistance parallel module is configured to input a first low level signal to an input end of the level inverter when the power module starts to work;
  • the level inverter is configured to output a first high level signal to a control end of the first switch tube according to the first low level signal when the DC power supply voltage rises to the first voltage threshold,
  • the first high level signal is used to control the first switch to be turned on.
  • the first switch tube T1 is a high-level switch tube, and the capacitor resistance parallel module is used to pull the indefinite level of the trigger output to the ground level after the power module is powered on and the trigger does not start working. Preventing the output of the flip-flop during the power-on process from being coupled to the input of the level inverter, ensuring that the signal of the input of the level inverter is low after the power module is powered up and the trigger does not start working. The signal does not jump, so that the output of the level inverter starts to work as a stable high level signal, ensuring that the first switching tube is stable in the on state, thereby ensuring the stability of the detonating sound suppression circuit.
  • the trigger is a D flip-flop.
  • the D flip-flop has a dedicated reset terminal that can be directly controlled by the reset module.
  • the operating voltage threshold of the reset module is a second voltage threshold
  • the operating voltage threshold of the trigger is a third voltage threshold
  • the operating voltage threshold of the controller is less than the second voltage threshold
  • the second voltage threshold is greater than the first voltage threshold
  • the second voltage threshold is less than or equal to the third voltage threshold
  • the reset module is configured to send a reset signal to the trigger when the DC supply voltage rises to the second voltage threshold;
  • the controller is configured to output a second low level signal to an input end of the trigger through the first control terminal when the DC power supply voltage rises to the second voltage threshold;
  • the flip-flop is configured to output the second low level signal to the level inversion according to the reset signal and the second low level signal when the DC supply voltage rises to the third voltage threshold Input of the device;
  • the level inverter is further configured to output a second high level signal to the control end of the first switch tube according to the second low level signal, where the second high level signal is used to control the first A switch tube is turned on.
  • the controller and the reset module control the trigger to start working, so that the trigger outputs a low level signal to the input of the level inverter to ensure the level inversion.
  • the device continues to output a high level signal that can turn the first switch on.
  • the signal output from the flip-flop to the level inverter is more controllable, and the stability of the plosive suppression circuit can be further ensured during the power-on of the power module.
  • the plosive suppression circuit further includes a common mode voltage generating module, an output end of the common mode voltage generating module is connected to an output end of the power amplifier, and an output end of the power module is connected to the common mode voltage Generating the power supply end of the module;
  • the controller is further configured to: when the DC power supply voltage is in a rising phase, control an output end of the common mode voltage generating module to be disconnected from the ground end;
  • the controller is further configured to control an output end of the common mode voltage generating module to be connected to the ground end when the DC power supply voltage is stabilized to a target voltage value.
  • the common mode voltage generating module is configured to connect the output end of the common mode voltage generating module to the ground end when the DC power supply voltage is stabilized to the target voltage value, thereby grounding the first end of the coupling capacitor through the common mode voltage generating module.
  • the plosive suppression circuit can further ground the first end of the coupling capacitor C1 through the common mode voltage generating module after the power supply of the single power module is completed. After the power module is powered on and before the common mode voltage is established, the first coupling capacitor is ensured. The terminal is always grounded, which can suppress the popping sound that may occur during the establishment of the common mode voltage after the power module is powered on.
  • the common mode voltage generating module includes a reference voltage generating module, an external capacitor, a buffer module, and a second switch tube, and an output end of the power module is connected to a power supply end of the reference voltage generating module and the buffer module
  • the power supply module is configured to provide the DC voltage supply voltage to the reference voltage generating module and the buffer module; the output end of the reference voltage generating module is connected to the first end of the external capacitor and the An input end of the buffer module, an output end of the buffer module is connected to a first end of the second switch tube, and a second end of the second switch tube is connected to an output end of the power amplifier, the second switch tube
  • the control end is connected to the second control end of the controller, the third control end of the controller is connected to the control end of the reference voltage generating module, and the fourth control end of the controller is connected to the control of the buffer module End, the second end of the external capacitor is connected to the ground end;
  • the controller is further configured to: when the DC power supply voltage is stabilized to the target voltage value, output a second control signal to the control end of the second switch tube through the second control terminal, and pass the third The control terminal outputs a third control signal to the control end of the reference voltage generating module, and the fourth control terminal outputs a fourth control signal to the control end of the buffer module, wherein the second control signal is used for control The second switch is turned on, the third control signal is used to control the reference voltage generating module to stop working, and the fourth control signal is used to control the buffer module to start working.
  • the control reference voltage generating module stops working, and the buffer module is controlled to work. Since the voltage output by the reference voltage generating module is zero when the operation is stopped, the zero voltage outputted by the reference voltage generating module when the operation is stopped can be output to the output end of the power amplifier through the buffer module, ensuring that the first end of the working coupling capacitor is always grounded. State, which can suppress the plosive sound that may be generated after the power module is powered on. Since the reference voltage generating module has no current driving capability, the output end (output node) of the power amplifier cannot be directly driven. Therefore, the buffer module is added to enable the reference voltage generated by the reference voltage generating module to drive the output of the power amplifier.
  • the controller is further configured to: after the second switch is turned on, output a third high level signal to the input end of the trigger through the first control end;
  • the flip-flop is further configured to output the third high level signal to an input end of the level inverter
  • the level inverter is further configured to output a third low level signal to a control end of the first switch tube according to the third high level signal, where the third low level signal is used to control the first A switch tube is turned off.
  • the common mode voltage can also be called reference voltage and reference voltage, in order to provide a voltage reference.
  • the controller is further configured to: when the second switch tube is turned on, and the first switch tube is turned off, outputting a fifth control signal to the reference voltage through the third control terminal to generate The control end of the module, the fifth control signal is used to control the reference voltage generating module to start working.
  • the reference voltage output by the reference voltage generating module will slowly rise to the final reference voltage value due to the presence of the external capacitor, and the buffer module also outputs the slowly rising reference voltage to the output of the power amplifier.
  • the terminal drives the voltage of the output of the power amplifier to a final reference voltage value, thereby establishing a common mode voltage at the output of the power amplifier.
  • the voltage at the output of the power amplifier rises slowly and does not abruptly, thereby suppressing the plosive sound that may be generated during the common mode voltage establishment process.
  • the capacitance of the external capacitor is greater than a preset capacitance threshold.
  • the capacitance of the external capacitor is greater than the preset capacitance threshold to ensure a smooth change of the voltage outputted from the buffer module to the output of the power amplifier, thereby suppressing the plosive sound caused by the change of the voltage at the output end of the power amplifier.
  • the audio playback circuit further includes a digital-to-analog converter, an input end of the digital-to-analog converter is connected to an output end of the controller, and an output end of the digital-to-analog converter is connected to an input of the power amplifier. End, the power supply end of the digital-to-analog converter is connected to an output end of the power module;
  • the digital to analog converter is configured to convert a digital audio signal output by the controller into an analog audio signal and output to the power amplifier.
  • a voltage change rate in a process in which the DC power supply voltage output by the power module changes from zero to the target voltage value is less than a preset change rate threshold.
  • the DC supply voltage outputted by the power module does not jump from zero to the final target voltage value, but has a slow rising process, avoiding the sudden change of the voltage outputted by the power module, causing the plosive suppression circuit to fail to react and affect the suppression of the plosive sound.
  • the plosive suppression effect of the circuit is not limited to:
  • a second aspect of the embodiments of the present invention provides an audio playback device, including the plosive suppression circuit according to the first aspect of the present invention.
  • a third aspect of the embodiments of the present invention provides an audio playback circuit, including a power module, a power amplifier, a coupling capacitor, and a plosive suppression circuit.
  • the power amplifier is configured to receive an analog signal, and the analog signal is amplified and output to the external device through the coupling capacitor;
  • the power module is configured to provide an operating voltage for the power amplifier and the plosive suppression circuit
  • Two ends of the coupling capacitor are respectively connected to an output end of the power amplifier and an input end of the external discharge device;
  • the plosive suppression circuit is configured to ground one end of the coupling capacitor when the operating voltage exceeds a threshold.
  • the one end of the coupling capacitor may be the first end of the coupling capacitor or the second end of the coupling capacitor.
  • the plosive suppression circuit can ground the output of the power amplifier or the input of the external device when the operating voltage exceeds the threshold. Preventing the level jump of the power module at the output of the power amplifier during the power-on process is coupled to the external device through the coupling capacitor to generate a popping sound, thereby suppressing the popping sound generated by the power module during the power-on process.
  • the plosive suppression circuit when the DC voltage outputted by the power module rises to the first voltage threshold, the plosive suppression circuit starts to work, and the output end of the plosive suppression circuit is grounded, thereby grounding the first end of the coupling capacitor.
  • the plosive suppression circuit grounds the output of the power amplifier when the power amplifier does not start working, preventing the power module from jumping horizontally at the output of the power amplifier during power-on, thereby preventing the The level jump is coupled to the load through the coupling capacitor to generate a plosive sound, thereby suppressing the popping sound generated by the power module during the power-on process.
  • FIG. 1 is a schematic structural diagram of an audio playback circuit according to an embodiment of the present invention.
  • FIG. 2 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention.
  • FIG. 3 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention.
  • FIG. 4 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention.
  • FIG. 5 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention.
  • FIG. 6 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention.
  • FIG. 7 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention.
  • FIG. 1 is a schematic structural diagram of an audio playback circuit according to an embodiment of the present invention.
  • the audio playback circuit can include a power module 11, a power amplifier 12, a coupling capacitor C1, and a load 13.
  • the output end of the power module 11 is connected to the power supply end of the power amplifier 12, the input end of the power amplifier 12 is connected to the analog audio signal, the output end of the power amplifier 12 is connected to the first end of the coupling capacitor C1, and the second end of the coupling capacitor C1 is connected to the load.
  • the positive pole of 13 and the negative pole of load 13 are grounded.
  • the power amplifier 12 amplifies the received analog audio signal and outputs the amplified analog audio signal to the load 13 through the coupling capacitor C1.
  • the power module 11 described in the embodiment of the present invention may be a single power module.
  • the single power supply module is a power supply module with only a positive power supply or a negative power supply, and can only output a positive voltage or a negative voltage, which is different from a dual voltage module capable of outputting a positive voltage and a negative voltage.
  • the output voltage range is 0-5V; if the nominal voltage of the dual voltage module is ⁇ 5V, the output voltage range is -5-+5V.
  • the load 13 is an AC load, and the load 13 can be driven by an AC signal.
  • the coupling capacitor C1 is used to isolate the DC signal output from the power amplifier 12, so as to avoid the DC signal on the load 13 causing interference to the load 13.
  • the load 13 can be a speaker or a speaker.
  • the analog audio signal can be input by an analog signal generator (eg, a digital to analog converter).
  • the power module 11 can provide a DC supply voltage to the power amplifier 12. It is assumed that the DC supply voltage supplied by the power module 11 is from 0-VDD, where VDD is the maximum voltage that the power module 11 can output. Before the power module 11 is powered on, the output node of the power amplifier 12 is at an indefinite level close to 0.
  • the output node of the power amplifier 12 When the power module 11 is powered on, and the power amplifier 12 does not receive the audio analog signal, the output node of the power amplifier 12 is powered.
  • the affected output of module 11 is an indeterminate level between 0-VDD.
  • the output node of the power amplifier 12 may have an indefinite level of transition, and the jump is easily transmitted to the coupling capacitor C1.
  • the load 13 is generated to generate a plosive sound. Plosive sounds can also be called pop sounds or noises.
  • FIG. 2 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention.
  • 2 is an audio playback circuit designed to suppress popping sound on the basis of FIG. 1.
  • the audio playback circuit includes a plosive suppression circuit 200 in addition to all the modules of FIG. among them:
  • the output end 121 of the power amplifier 12 is connected to the first end of the coupling capacitor C1 and the output end 201 of the plosive suppression circuit 200.
  • the second end of the coupling capacitor C1 is connected to the load 13.
  • the output end 111 of the power module 11 is connected to the power supply of the power amplifier 12.
  • a power supply end of the plosive suppression circuit 200; the power module 11 is configured to provide a DC supply voltage for the power amplifier 12 and the plosive suppression circuit 200;
  • the plosive suppression circuit 200 is configured to disconnect the first end of the coupling capacitor C1 from the ground GND when the DC supply voltage is lower than the first voltage threshold, and the first voltage threshold is lower than the operating voltage threshold of the power amplifier 12;
  • the plosive suppression circuit 200 is further configured to connect the first end of the coupling capacitor C1 to the ground when the DC supply voltage rises to the first voltage threshold.
  • the power supply voltage outputted by the power module 11 rises from 0.
  • the power supply voltage output from the power module 11 rises to VDD and remains stable
  • the power module 11 is powered on.
  • the lowest voltage threshold at which the plosive suppression circuit 200 can operate is the first voltage threshold.
  • the output terminal 121 of the power amplifier 12 outputs an indefinite level with a small amplitude fluctuation close to 0, which is close.
  • An indefinite level in which the amplitude fluctuation of 0 is small is transmitted even to the load 13 through the coupling capacitor C1, and no plosive sound is generated. Therefore, when the power supply voltage outputted by the power module 11 is lower than the first voltage threshold, the popping sound suppression circuit 200 does not operate, and the capacitor C1 does not need to be grounded, so that power consumption can be saved.
  • the magnitude of the indefinite level of the power supply voltage output from the power module 11 fluctuates greatly, and may be transmitted to the load 13 through the coupling capacitor C1, thereby generating a popping sound.
  • the first voltage threshold that is, the lowest voltage threshold at which the plosive suppression circuit 200 can operate
  • the plosive suppression circuit 200 can start working, and the first end of the coupling capacitor C1 is started.
  • connection to the ground GND can prevent the level of the output terminal 121 of the power amplifier 12 from jumping after the power module 11 is powered on, and the power amplifier 12 does not start to operate, thereby preventing the jump from easily passing through the coupling capacitor.
  • C1 is transmitted to the load 13 to generate a plosive sound.
  • the plosive suppression circuit 200 may include only one switch tube, and may also include a capacitor, a resistor, and a switch tube.
  • the plosive suppression circuit 200 when the plosive suppression circuit 200 includes only one switch tube, the first end of the switch tube is connected to the ground end, and the second end of the switch tube is connected to the output end 121 of the power amplifier 12, and the control end of the switch tube The output end 111 of the power module 11 is directly connected, wherein the turn-on voltage of the switch tube is the first voltage threshold.
  • the switching transistor may be any one of a metal oxide semiconductor (MOS) field effect transistor, an insulated gate bipolar transistor (IGBT), and a semiconductor switching transistor such as a triode.
  • the plosive suppression circuit 200 in the embodiment of the present invention includes only one switch tube, which can save material costs.
  • the plosive suppression circuit 200 includes a capacitor, a resistor, and a switch
  • the first end of the capacitor, the first end of the resistor, and the control end of the switch can be connected to the output 111 of the power module 11.
  • the first end of the switch tube, the second end of the capacitor is connected to the ground end of the resistor, and the second end of the switch tube is connected to the output end 121 of the power amplifier 12, and the popping sound suppression in the embodiment of the invention
  • the circuit 200 includes a capacitor and a resistor in parallel, which can ensure that the voltage of the control terminal of the switch tube can rise slowly when the power module 11 is powered on, and can prevent the influence of the output voltage of the output terminal 111 of the power module 11 from being unstable on the switch tube. To ensure the stability of the operation of the plosive suppression circuit 200.
  • the audio playback circuit may further include a controller for disconnecting the first end of the coupling capacitor C1 from the ground before the power amplifier 12 performs normal analog signal amplification.
  • the power amplifier 12 in order to ensure that the power amplifier 12 is not affected by other modules of the audio playback circuit, it is generally required that the power amplifier 12 starts after all the modules of the audio playback circuit are powered on and the working states of all the modules are stable. Perform normal analog signal amplification and output. After all modules of the audio playback circuit are powered up and the operating states of all modules are stable, and before the power amplifier 12 performs normal analog signal amplification, since the power amplifier 12 at this time is not subjected to other modules of the audio playback circuit The impact causes a popping sound. Therefore, the first end of the coupling capacitor C1 can be disconnected from the ground by the controller, thereby restoring the audio playback circuit to the normal audio playback function.
  • the audio playback circuit shown in FIG. 2 is implemented, and the plosive suppression circuit is adopted to enable the plosive suppression circuit to start working at a lower voltage to prevent the power module from jumping horizontally at the output end of the power amplifier during the power-on process. Preventing the level jump from being coupled to the load through the coupling capacitor generates a plosive sound, thereby suppressing the popping sound generated by the power module during the power-on process.
  • FIG. 3 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention. 3 is further optimized on the basis of FIG. 2, as shown in FIG. 3, the audio playback circuit further includes a controller 14, and the plosive suppression circuit 200 includes a reset module 211, a flip-flop 212, a capacitor resistance parallel module 213, and an electric
  • the output of the reset module 211 is connected to the reset end of the flip-flop 212, the input end of the flip-flop 212 is connected to the first control terminal 141 of the controller 14, and the output of the flip-flop 212 is connected to the capacitor.
  • the first end of the resistance parallel module 213 and the input end of the level inverter 214, the output end of the level inverter 214 is connected to the control end of the first switch tube T1, and the first end of the first switch tube T1 is connected to the power amplifier 12
  • the output end 121, the second end of the first switch tube T1 and the second end of the capacitor resistance parallel module 213 are connected to the ground end GND, and the operating voltage threshold of the level inverter 214 is equal to the first voltage threshold, that is, the level inverter 214 is When the supply voltage is lower than the first voltage threshold, it cannot work, and when the supply voltage reaches the first voltage threshold, it starts to work.
  • the output end of the power module 11 is connected to the power supply end of the controller 14, the power supply end of the reset module 211, the power supply end of the flip-flop 212, and the power supply end of the level inverter 214.
  • the power module 11 is used for the reset module 211 and the flip-flop 212.
  • level inverter 214 provides a DC supply voltage;
  • the capacitor resistance parallel module 213 is configured to input a first low level signal to the input end of the level inverter 214 when the power module 11 starts to work;
  • the level inverter 214 is configured to output a first high level signal to the control end of the first switch tube T1 according to the first low level signal when the DC power supply voltage rises to the first voltage threshold, and the first high level signal is used.
  • the first switch tube T1 is controlled to be turned on.
  • the operating voltage threshold of the reset module 211 is a second voltage threshold
  • the operating voltage threshold of the flip-flop 212 is a third voltage threshold
  • the operating voltage threshold of the controller 14 is less than the second voltage threshold
  • the second voltage threshold is greater than the first a voltage threshold, the second voltage threshold being less than or equal to a third voltage threshold
  • the reset module 211 is configured to send a reset signal to the flip-flop 212 when the DC power supply voltage rises to the second voltage threshold;
  • the controller 14 is configured to output a second low level signal to the input end of the flip flop 212 through the first control terminal 141 when the DC power supply voltage rises to the second voltage threshold;
  • the flip-flop 212 is configured to output a second low level signal to the input end of the level inverter 214 according to the reset signal and the second low level signal when the DC supply voltage rises to the third voltage threshold;
  • the level inverter 214 is further configured to output a second high level signal to the control end of the first switch tube T1 according to the second low level signal, and the second high level signal is used to control the first switch tube T1 to be turned on.
  • the capacitor resistance parallel module 213 is formed by connecting the pull-down resistor R1 and the capacitor C2 in parallel, which can prevent the level input by the level inverter 214 from changing rapidly.
  • Level inverter 214 is used to convert the input low level to a high level output and to convert the input high level to a low level output.
  • level inverter 214 can operate at a lower operating voltage threshold, while flip-flop 212 needs to operate at a relatively high operating voltage threshold.
  • the operating voltage threshold of the level inverter is 0.7V
  • the operating voltage threshold of the reset module 211 is 1.2V
  • the operating voltage threshold of the flip-flop 212 is 1.4V.
  • the output of the level inverter 214, the reset module 211, and the flip-flop 212 is an indefinite level close to 0, and the capacitor resistance parallel module 213 can pull the indefinite level of the output of the flip-flop 212 to the ground level to prevent the trigger.
  • the unsteady state outputted during power-up is coupled to the input of the level inverter 214, ensuring that the signal at the input of the level inverter 214 is low after the power module 11 is powered up and the flip-flop 212 is not operating. The signal is flat and does not jump.
  • the level inverter 214 When the supply voltage of the power module 11 is greater than the first voltage threshold and less than the second voltage threshold, the level inverter 214 starts to operate, and the reset module 211 and the flip-flop 212 are inoperable. At this time, since the signal of the input terminal of the level inverter 214 is a low level signal and no jump occurs, the level inverter 214 outputs a stable high level signal to ensure that the first switching transistor T1 is stably turned on. Thereby, the first end of the coupling capacitor C1 is pulled to the ground level.
  • the level inverter 214 continues to operate, the reset module 211 begins to operate, and the flip-flop 212 does not operate. Since the flip-flop 212 needs to operate under the reset signal of the reset module 211, the reset module 211 is allowed to start operating before the flip-flop 212 operates, and the flip-flop 212 can be prepared for operation.
  • the level inverter 214 and the reset module 211 continue to operate, and the flip-flop 212 begins to operate.
  • the flip-flop 212 outputs a low level signal to the input terminal of the level inverter 214 according to the reset signal input by the reset module 211, the clock signal input by the clock generator, and the low level signal input by the controller 14.
  • the level inverter 214 outputs a high level signal to the first switching transistor T1 according to the input low level signal, so that the first switching transistor T1 is turned on, thereby continuing to pull the first end of the coupling capacitor C1 to the ground level. .
  • the controller 14 is configured to control the reset signal input by the flip-flop 212 according to the reset module 211 before all modules of the audio playback circuit are powered on and the operating states of all the modules are stabilized, and before the power amplifier 12 performs normal analog signal amplification.
  • the clock signal input by the clock generator and the high level signal input by the controller 14 output a high level signal to the input terminal of the level inverter 214, and the level inverter 214 outputs a low level signal according to the input high level signal.
  • the first switching transistor T1 is turned off to disconnect the first end of the coupling capacitor C1 from the ground.
  • the low-level signal outputted by the flip-flop 212 to the level inverter 214 is more controllable, and the operation of the pop-up suppression circuit 200 can be further ensured during the power-on of the power module 11. Sex.
  • the trigger 212 can accurately control the first switch T1 through the clock signal and the controller 14, so that the first end of the coupling capacitor C1 can be accurately connected or disconnected from the ground. Thereby achieving precise suppression of the plosive sound.
  • the trigger 212 can be a D flip-flop, an RS flip-flop, or the like.
  • the flip-flops in FIG. 3 and subsequent figures are illustrated by taking a D flip-flop as an example.
  • the operating voltage threshold of the level inverter 214 is the lowest, lower than the operating voltage threshold of the reset module 211 and the flip-flop 212.
  • the trigger 212 is controlled by the controller 14 and the reset module 211 to start the operation, so that the flip-flop 212 outputs a low level signal to the input of the level inverter 214.
  • the guaranteed level inverter 214 continues to output a high level signal capable of turning on the first switching transistor T1.
  • the low-level signal outputted by the flip-flop 212 to the level inverter 214 is more controllable, and the stability of the sound suppression circuit 200 can be further stabilized during the power-on of the power module 11. .
  • FIG. 4 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention. 4 is further optimized on the basis of FIG. 3.
  • the plosive suppression circuit 200 further includes a common mode voltage generating module 22, and the output terminal 220 of the common mode voltage generating module 22 is connected to the power amplifier 12.
  • the output end 121, the output end of the power module 11 is connected to the power supply end of the common mode voltage generating module 22;
  • the controller 14 is further configured to control the output terminal 220 of the common mode voltage generating module 22 to be disconnected from the ground when the DC power supply voltage is in the rising phase;
  • the controller 14 is further configured to control the output terminal 220 of the block of the common mode voltage generating module 22 to be connected to the ground when the DC supply voltage is stabilized to the target voltage value.
  • the output DC voltage of the power module 11 gradually rises from 0 to the target voltage value.
  • the target voltage value can be 3.3V.
  • the common mode voltage generating module 22 prevents the common mode voltage generating module 22 from operating when the DC power supply voltage is in the rising phase, that is, when the power module 11 is in the power-on process, and the output of the common mode voltage generating module 22 is disabled.
  • the terminal 220 is disconnected from the ground GND, and the level of the output terminal 220 of the common mode voltage generating module 22 is an indefinite level close to zero.
  • the common mode voltage generating module 22 can start to operate, and the output terminal 220 of the common mode voltage generating module 22 is connected to the ground GND.
  • the plosive suppression circuit 200 can ground the first end of the coupling capacitor C1 through the reset module 211, the flip-flop 212, the capacitor resistance parallel module 213, the level inverter 214, and the first switch T1 during the power-on of the single power module 11.
  • the plosive suppression circuit 200 can further ground the first end of the coupling capacitor C1 through the common mode voltage generating module 22 after the single power supply module 11 is powered on.
  • the first end of the coupling capacitor C1 is always grounded, so that the plosive sound that may be generated during the establishment of the common mode voltage after the power module 11 is powered on can be suppressed. .
  • the common mode voltage generating module 22 may include only one switching transistor, and may also include a capacitor, a resistor, and a switching transistor.
  • the common mode voltage generating module 22 includes only one switch tube
  • the first end of the switch tube is connected to the ground end
  • the second end of the switch tube is connected to the output end 121 of the power amplifier 12, and the switch tube is controlled.
  • the terminal is directly connected to the output end 111 of the power module 11, wherein the turn-on voltage of the switch is the second voltage threshold.
  • the switching transistor can be a metal-oxide-semiconductor field effect transistor, an insulated gate bipolar transistor, a semiconductor transistor such as a triode.
  • the common mode voltage generating module 22 in the embodiment of the present invention includes only one switching tube, which can save material costs.
  • the common mode voltage generating module 22 includes a capacitor, a resistor and a switch
  • the first end of the capacitor, the first end of the resistor, and the control end of the switch can be connected to the output 111 of the power module 11.
  • the first end of the switch, the second end of the capacitor is connected to the second end of the resistor, and the second end of the switch is connected to the output end 121 of the power amplifier 12, which is a common mode in the embodiment of the present invention.
  • the voltage generating module 22 includes a capacitor and a resistor in parallel.
  • the plosive sound suppression circuit shown in FIG. 4 is implemented, and the common mode voltage generating module can be used to ensure that the output end of the power amplifier is always grounded after the power module is powered on and before the common mode voltage is established, so that the power module 11 can be suppressed.
  • the plosive sound that may be generated during the process of establishing the common mode voltage after the electricity is completed.
  • FIG. 5 is a schematic structural diagram of another pop-up audio playing circuit according to an embodiment of the present invention. 5 is further optimized on the basis of FIG. 4, as shown in FIG. 5, the common mode voltage generating module 22 includes a reference voltage generating module 221, an external capacitor C3, a buffer module 222, and a second switching transistor T2, and the power module 11
  • the output terminal is connected to the power supply end of the reference voltage generating module 221 and the power supply end of the buffer module 222;
  • the power module 11 is configured to provide a DC power supply voltage for the reference voltage generating module 221 and the buffer module 222;
  • the output terminal of the reference voltage generating module 221 is connected to the plug-in
  • the first end of the capacitor C3 and the input end of the buffer module 222, the output end of the buffer module 222 is connected to the first end of the second switch tube T2, and the second end of the second switch tube T2 is connected to the output end 121 of the power amplifier 12,
  • the control end of the second switch T2 is connected to the
  • the third control end 143 of the controller 14 is connected to the control end of the reference voltage generating module 221, and the fourth control end 144 of the controller 14 is connected to the buffer module 222.
  • Control end, the second end of the external capacitor C3 is connected to the ground end;
  • the controller 14 is configured to output a second control signal to the control end of the second switch tube T2 through the second control terminal 142 when the DC power supply voltage is stabilized to the target voltage value, and output the third control signal to the reference voltage through the third control terminal.
  • the control terminal of the generating module 221 outputs a fourth control signal to the control end of the buffer module 222 through the fourth control terminal, wherein the second control signal is used to control the second switch tube T2 to be turned on, and the third control signal is used to control the reference.
  • the voltage generating module 221 stops working, and the fourth control signal is used to control the buffer module 222 to start working.
  • the common mode voltage generating module 22 is for suppressing the plosive sound due to the establishment of the common mode voltage.
  • the controller 14 controls the reference voltage generating module 221 to stop working, and controls the buffer module 222 to operate. Since the voltage output by the reference voltage generating module 221 when the operation is stopped is zero, the zero voltage output by the reference voltage generating module 221 when the operation is stopped can be output to the output terminal 121 of the power amplifier 12 through the buffer module 222 to ensure the coupling capacitor C1.
  • One end is always in a grounded state, so that the plosive sound that may be generated after the power module 11 is powered on can be suppressed.
  • the buffer module 222 is added to enable the reference voltage generated by the reference voltage generating module 221 to drive the output terminal 121 of the power amplifier 12.
  • the reference voltage generating module 221 and the external capacitor C3 are used to provide a low noise voltage reference.
  • controller 14 is further configured to output a third high level signal to the input end of the flip flop 212 through the first control end 141 after the second switch tube T2 is turned on;
  • the flip-flop 212 is further configured to output a third high level signal to the input end of the level inverter 214;
  • the level inverter 214 is further configured to output a third low level signal to the control end of the first switch tube T1 according to the third high level signal, and the third low level signal is used to control the first switch tube T1 to be turned off.
  • the common mode voltage can also be called reference voltage and reference voltage, in order to provide a voltage reference.
  • the first switch T1 is turned off by the controller 14. The first terminal T1 is prevented from affecting the output terminal 121 of the power amplifier 12 to establish a common mode voltage.
  • the controller 14 is further configured to: when the second switch T2 is turned on, and after the first switch T1 is turned off, output a fifth control signal to the control end of the reference voltage generating module 221 through the third control end 143, The fifth control signal 221 is used to control the reference voltage generation module 221 to start operating.
  • the reference voltage output by the reference voltage generating module 221 will slowly rise to the final reference voltage value due to the presence of the external capacitor C3, and the buffer module 222 also outputs the slowly rising reference voltage to the reference voltage.
  • the output 121 of the power amplifier 12 drives the voltage at the output 121 of the power amplifier 12 to a final reference voltage value, thereby achieving a common mode voltage at the output 121 of the power amplifier 12.
  • the voltage at the output terminal 121 of the power amplifier 12 is slowly rising due to the presence of the external capacitor C3, and no sudden change occurs, so that blasting which may occur during the common mode voltage establishing process can be suppressed. sound.
  • the reference voltage generating module 221 and the external capacitor C3 are used in combination with the buffer module 222 for realizing a common mode voltage ramping from 0 to a final reference voltage value.
  • the capacitance of the external capacitor C3 is greater than a preset capacitance threshold. Setting the external capacitor as large as possible can ensure the stability of the reference voltage generated by the reference voltage generating module 221, and is not easy to fluctuate.
  • the power module 11 continues to be powered on.
  • the voltage VDD outputted by the power module 11 reaches the operating voltage threshold (first voltage threshold) of the level inverter 214
  • the plosive suppression circuit 200 starts operating, and the level inverter 214
  • the high level is output to the first switching transistor T1 according to the input zero level to turn on the first switching transistor T1, and the output terminal 121 of the power amplifier 12 is pulled to the ground level through the first switching transistor T1.
  • the power module 11 continues to be powered on.
  • the voltage VDD outputted by the power module 11 reaches the operating voltage threshold (third voltage threshold) of the flip-flop 212, the controller 14, the reset module 211, and the flip-flop 212 start to work, triggering.
  • the device 212 outputs a low level signal to the input terminal of the level inverter 214 according to the reset signal input by the reset module 211 and the low level signal input by the controller 14, and the level inverter 214 outputs the high voltage according to the input low level signal.
  • the signal is tied to the first switching transistor T1 to turn on the first switching transistor T1, thereby continuing to pull the output terminal 121 of the power amplifier 12 to the ground level.
  • the voltage VDD outputted by the power module 11 continues to rise until the power-on is completed.
  • the controller 14 turns on the buffer module 222, and turns off the reference voltage generating module 221.
  • the reference voltage generating module 221 outputs 0, and the controller 14 controls the second switching tube T2 to be turned on.
  • the second switching transistor T2 pulls the output terminal 121 of the power amplifier 12 to the ground level.
  • the output terminal 121 of the power amplifier 12 is simultaneously pulled to the ground level (ie, the 0 level) by the first switching transistor T1 and the second switching transistor T2, so that the output terminal 121 of the power amplifier 12 does not cause a level jump. change.
  • the first control terminal 141 of the controller 14 After the second switching transistor T2 is turned on, the first control terminal 141 of the controller 14 outputs a high level signal to turn off the first switching transistor T1, and is coupled during power-on of the power module 11
  • the first end of the capacitor C1 is always maintained at the ground level, so that the output terminal 121 of the power amplifier 12 does not undergo a level jump, and no plosive sound is generated during the power-on of the power module 11.
  • the controller 14 controls the reference voltage generating module 221 to start working, and the output of the reference voltage generating module 221 is output due to the presence of the external capacitor C3.
  • the reference voltage will slowly rise to the final reference voltage value, and the buffer module 222 also outputs the slowly rising reference voltage to the output terminal 121 of the power amplifier 12 to drive the voltage of the output terminal 121 of the power amplifier 12 to the final reference voltage value. Thereby a common mode voltage is established at the output 121 of the power amplifier 12.
  • the voltage at the output terminal 121 of the power amplifier 12 is slowly rising without abrupt change, so that the plosive sound which may be generated during the common mode voltage establishing process can be suppressed.
  • the common mode voltage of the output terminal 121 of the power amplifier 12 is established, when the power amplifier 12 starts operating, since the input of the power amplifier 12 is zero, the voltage that the power amplifier 12 just starts to output is also a common mode voltage, and does not cause power.
  • the voltage at the output terminal 121 of the amplifier 12 is hopped, thereby suppressing the plosive sound due to the change in the voltage of the output terminal 121 of the power amplifier 12.
  • FIG. 6 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention.
  • the audio playback circuit further includes a digital-to-analog converter 15, the input end of the digital-to-analog converter 15 is connected to the output end of the controller 14, and the output end of the digital-to-analog converter 15 is connected to the input end of the power amplifier 12, and the power supply of the digital-to-analog converter 15 is provided.
  • the end is connected to the output end of the power module 11;
  • the digital-to-analog converter 15 is for converting the digital audio signal output from the controller 14 into an analog audio signal and outputting it to the power amplifier 12.
  • the controller 14 may output the digital audio signal to the digital-to-analog converter 15, which converts the digital audio signal into an analog audio signal and outputs it to the power amplifier 12, and then passes through the power amplifier 12 The analog audio signal is amplified and output to the load 13.
  • the voltage change rate of the DC power supply voltage outputted by the power module 11 from zero to the target voltage value is less than a preset rate of change threshold.
  • the DC supply voltage outputted by the power module 11 does not jump from zero to the final stable voltage value, but has a slow rising process, and the sudden change of the voltage outputted by the power module 11 causes the plosive suppression circuit 20021 to have a reaction.
  • the plosive suppression effect of the plosive suppression circuit 200 is not limited to the DC supply voltage outputted by the power module 11 and the sudden change of the voltage outputted by the power module 11.
  • FIG. 7 is a schematic structural diagram of another audio playback circuit according to an embodiment of the present invention.
  • the audio playback circuit includes a power module 11, a power amplifier 12, a coupling capacitor C1, an external device 30, and a plosive suppression circuit 200.
  • the power amplifier 12 is used to receive an analog signal, the analog signal is amplified and output to the external device 30 through the coupling capacitor C1;
  • the power module 11 is configured to provide an operating voltage for the power amplifier 12 and the plosive suppression circuit 200;
  • the two ends of the coupling capacitor C1 are respectively connected to the output end 121 of the power amplifier 12 and the input end 301 of the external device 30;
  • the plosive suppression circuit 200 is for grounding one end of the coupling capacitor C1 when the operating voltage exceeds the threshold.
  • one end of the coupling capacitor C1 may be the first end of the coupling capacitor C1 or the second end of the coupling capacitor C1.
  • the plosive suppression circuit 200 can ground the output 121 of the power amplifier 12 or the input 301 of the external device 30 when the operating voltage exceeds the threshold.
  • the plosion suppression circuit 200 can ground one end of the coupling capacitor C1 when the operating voltage outputted by the power module 11 exceeds the threshold, and prevent the output of the power amplifier 12 during the power-on process of the power module 11.
  • the level jump occurring at the terminal is coupled to the external discharge device 30 through the coupling capacitor C1 to generate a popping sound, so that the popping sound generated by the power module 11 during the power-on process can be suppressed.
  • the embodiment of the invention further discloses an audio playing device, which may include the audio playing circuit shown in any of the figures of FIG. 2 to FIG.
  • the audio playing circuit in the embodiment of the invention can be used for mobile terminals such as mobile phones and tablet computers, and can also be applied to audio playing devices such as speakers and television players.
  • the controller 14 in the embodiment of the present invention may be a Micro Control Unit (MCU) in an audio playback device, or may be an Application Processor (AP) in a mobile terminal.
  • MCU Micro Control Unit
  • AP Application Processor
  • the low-voltage working module grounds the output end of the power amplifier when the power amplifier does not start working, and prevents the output of the power amplifier during the power-on process of the power module.
  • a level jump occurs at the terminal, thereby preventing the level jump from being coupled to the load through the coupling capacitor to generate a popping sound, thereby suppressing the popping sound generated by the power module during the power-on process.

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Abstract

一种音频播放电路以及音频播放设备。该音频播放电路包括电源模块、功率放大器、耦合电容、负载以及爆破音抑制电路，功率放大器的输出端连接耦合电容的第一端以及爆破音抑制电路的输出端，耦合电容的第二端连接负载，电源模块的输出端连接功率放大器的供电端以及爆破音抑制电路的供电端；电源模块用于为功率放大器和爆破音抑制电路提供直流供电电压。当直流供电电压低于第一电压阈值时，爆破音抑制电路将耦合电容的第一端与地端断开连接；当直流供电电压上升至第一电压阈值时，爆破音抑制电路将耦合电容的第一端与地端连接。采用本发明实施例，可以抑制单电源供电的音频播放设备在电源上电过程中产生的爆破音。

Description

音频播放电路以及音频播放设备 技术领域
本发明涉及电子电力领域，尤其涉及一种音频播放电路以及音频播放设备。
背景技术
当音箱、耳机等音频播放设备接通电源时，往往会产生“吱吱”的令人不愉悦的声音，这种令人不愉悦的声音称为爆破音，也可以称为pop音或者杂音。音频播放设备一般包括音频功放电路、耦合电容和负载，音频功放电路通过耦合电容连接负载。
对于单电源供电的音频播放设备，在单电源上电之前，音频功放电路输出节点为接近0的不定电平，当单电源上电完成后，输出节点会从接近0的不定电平瞬间变成有一定电平值的不定电平(0至单电源电压之间的不定电平)，输出节点的电平从接近0的不定电平快速变成有一定电平值的不定电平，这种快速的电平变化则有可能通过耦合电容耦合到负载上，从而产生爆破音。
发明内容
本发明实施例所要解决的技术问题在于，提供一种音频播放电路以及音频播放设备，可以抑制音频播放设备在电源模块上电过程中产生的爆破音。
本发明实施例第一方面提供了一种音频播放电路，包括电源模块、功率放大器、耦合电容、负载以及爆破音抑制电路，其中：
所述功率放大器的输出端连接所述耦合电容的第一端以及所述爆破音抑制电路的输出端，所述耦合电容的第二端连接所述负载，所述电源模块的输出端连接所述功率放大器的供电端以及所述爆破音抑制电路的供电端；所述电源模块用于为所述功率放大器和所述爆破音抑制电路提供直流供电电压；
所述爆破音抑制电路用于当所述直流供电电压低于第一电压阈值时，将所述耦合电容的第一端与地端断开连接，所述第一电压阈值低于所述功率放大器的工作电压阈值；
所述爆破音抑制电路还用于当所述直流供电电压上升至所述第一电压阈值时，将所述耦合电容的第一端与所述地端连接。
其中，负载可以为喇叭或扬声器，爆破音抑制电路的工作电压阈值为低于功率放大器的工作电压阈值的第一电压阈值，当电源模块输出的直流电压上升至第一电压阈值时，爆破音抑制电路开始工作，并且将爆破音抑制电路的输出端接地，从而将耦合电容的第一端接地。在电源模块的上电过程中，将耦合电容的第一端接地，防止电源模块在上电过程中功率放大器的输出端出现电平跳变，进而防止该电平跳变通过耦合电容耦合到负载上产生爆破音，从而可以抑制电源模块在上电过程中产生的爆破音。
可选的，所述音频播放电路还包括控制器，所述爆破音抑制电路包括复位模块、触发器、电容电阻并联模块、电平反相器以及第一开关管，所述复位模块的输出端连接所述触发器的复位端，所述触发器的输入端连接所述控制器的第一控制端，所述触发器的输出端连接所述电容电阻并联模块的第一端以及所述电平反相器的输入端，所述电平反相器的输 出端连接所述第一开关管的控制端，所述第一开关管的第一端连接所述功率放大器的输出端，所述第一开关管的第二端以及所述电容电阻并联模块的第二端连接所述地端，所述电平反相器的工作电压阈值等于所述第一电压阈值；
所述电源模块的输出端连接所述控制器的供电端、所述复位模块的供电端、所述触发器的供电端以及所述电平反相器的供电端；所述电源模块用于为所述复位模块、所述触发器和所述电平反相器提供所述直流供电电压；
所述电容电阻并联模块用于当所述电源模块开始工作时，向所述电平反相器的输入端输入第一低电平信号；
所述电平反相器用于当所述直流供电电压上升至所述第一电压阈值时，根据所述第一低电平信号输出第一高电平信号至所述第一开关管的控制端，所述第一高电平信号用于控制所述第一开关管导通。
其中，第一开关管T1为高电平导通的开关管，电容电阻并联模块用于在电源模块上电后且触发器未开始工作时，将触发器输出的不定电平拉至地电平，防止触发器在上电过程中输出的不定态耦合至电平反相器的输入端，保证在电源模块上电后且触发器未开始工作时，电平反相器的输入端的信号为低电平信号且不会发生跳变，进而保证电平反相器开始工作后其输出为稳定的高电平信号，保证第一开关管稳定在导通状态，从而保证爆破音抑制电路工作的稳定性。
可选的，所述触发器为D触发器。D触发器设有专门的复位端，可以由复位模块直接控制。
可选的，所述复位模块的工作电压阈值为第二电压阈值，所述触发器的工作电压阈值为第三电压阈值，所述控制器的工作电压阈值小于所述第二电压阈值，所述第二电压阈值大于所述第一电压阈值，所述第二电压阈值小于或等于所述第三电压阈值；
所述复位模块用于当所述直流供电电压上升至所述第二电压阈值时，向所述触发器发送复位信号；
所述控制器用于当所述直流供电电压上升至所述第二电压阈值时，通过所述第一控制端输出第二低电平信号至所述触发器的输入端；
所述触发器用于当所述直流供电电压上升至所述第三电压阈值时，根据所述复位信号以及所述第二低电平信号输出所述第二低电平信号至所述电平反相器的输入端；
所述电平反相器还用于根据所述第二低电平信号输出第二高电平信号至所述第一开关管的控制端，所述第二高电平信号用于控制所述第一开关管导通。
其中，在电源模块上电且电平反相器开始工作后，通过控制器和复位模块控制触发器开始工作，以使触发器输出低电平信号至电平反相器的输入端，保证电平反相器继续输出能够将第一开关管导通的高电平信号。与电容电阻并联模块相比，触发器输出至电平反相器的信号的可控性更高，可以在电源模块上电过程中进一步保证爆破音抑制电路工作的稳定性。
可选的，所述爆破音抑制电路还包括共模电压产生模块，所述共模电压产生模块的输出端连接所述功率放大器的输出端，所述电源模块的输出端连接所述共模电压产生模块的供电端；
所述控制器还用于当所述直流供电电压处于上升阶段时，控制所述共模电压产生模块的输出端与所述地端断开连接；
所述控制器还用于当所述直流供电电压稳定至目标电压值时，控制所述共模电压产生模块的输出端与所述地端连接。
其中，当直流供电电压处于上升阶段时，表明电源模块正在进行上电；当直流供电电压稳定至目标电压值时，表明电源模块已经上电完成。共模电压产生模块用于在直流供电电压稳定至目标电压值时将共模电压产生模块的输出端与地端连接，从而通过共模电压产生模块将耦合电容的第一端接地。爆破音抑制电路可以在单电源模块上电完成后进一步通过共模电压产生模块将耦合电容C1的第一端接地可以在电源模块上电完成后、共模电压建立之前，保证耦合电容的第一端始终接地，从而可以抑制在电源模块上电完成后共模电压建立的过程中可能产生的爆破音。
可选的，所述共模电压产生模块包括参考电压产生模块、外挂电容、缓冲模块以及第二开关管，所述电源模块的输出端连接所述参考电压产生模块的供电端以及所述缓冲模块的供电端；所述电源模块用于为所述参考电压产生模块以及所述缓冲模块提供所述直流供电电压；所述参考电压产生模块的输出端连接所述外挂电容的第一端以及所述缓冲模块的输入端，所述缓冲模块的输出端连接所述第二开关管的第一端，所述第二开关管的第二端连接所述功率放大器的输出端，所述第二开关管的控制端连接所述控制器的第二控制端，所述控制器的第三控制端连接所述参考电压产生模块的控制端，所述控制器的第四控制端连接所述缓冲模块的控制端，所述外挂电容的第二端连接所述地端；
所述控制器还用于当所述直流供电电压稳定至所述目标电压值时，通过所述第二控制端输出第二控制信号至所述第二开关管的控制端，通过所述第三控制端输出第三控制信号至所述参考电压产生模块的控制端，通过所述第四控制端输出第四控制信号至所述缓冲模块的控制端，其中，所述第二控制信号用于控制所述第二开关管导通，所述第三控制信号用于控制所述参考电压产生模块停止工作，所述第四控制信号用于控制所述缓冲模块开始工作。
其中，在电源模块上电完成后、共模电压建立之前，控制参考电压产生模块停止工作，控制缓冲模块工作。由于参考电压产生模块在停止工作时输出的电压为零，参考电压产生模块在停止工作时输出的零电压可以通过缓冲模块输出至功率放大器的输出端，保证功耦合电容的第一端始终处于接地状态，从而可以抑制在电源模块上电完成后可能产生的爆破音。由于参考电压产生模块没有电流驱动能力，无法直接驱动功率放大器的输出端(输出节点)，因此，增加缓冲模块是为了使参考电压产生模块产生的参考电压能够驱动功率放大器的输出端。
可选的，所述控制器还用于当所述第二开关管导通之后，通过所述第一控制端输出第三高电平信号至所述触发器的输入端；
所述触发器还用于将所述第三高电平信号输出至所述电平反相器的输入端；
所述电平反相器还用于根据所述第三高电平信号输出第三低电平信号至所述第一开关管的控制端，所述第三低电平信号用于控制所述第一开关管关断。
其中，共模电压也可以称为参考电压、基准电压，是为了提供一个电压基准。在电源 模块上电完成后、共模电压建立之前，由于电源模块已完成上电，为了在功率放大器的输出端建立共模电压，通过控制器第一开关管关断，让爆破音抑制电路停止工作，避免第一开关管开启后影响功率放大器的输出端建立共模电压。
可选的，所述控制器还用于当所述第二开关管导通，并且所述第一开关管关断之后，通过所述第三控制端输出第五控制信号至所述参考电压产生模块的控制端，所述第五控制信号用于控制所述参考电压产生模块开始工作。
其中，参考电压产生模块开始工作时，由于有外挂电容的存在，参考电压产生模块输出的参考电压会缓慢上升至最终的参考电压值，缓冲模块也将缓慢上升的参考电压输出至功率放大器的输出端，以驱动功率放大器的输出端的电压为最终的参考电压值，从而实现在功率放大器的输出端建立共模电压。在建立共模电压的过程中，功率放大器的输出端的电压是缓慢上升的，并不会发生突变，从而可以抑制在共模电压建立过程中可能产生的爆破音。当功率放大器的输出端的共模电压建立之后，功率放大器开始工作时，由于功率放大器的输入为零，则功率放大器刚开始输出的电压也是共模电压，也不会导致功率放大器的输出端的电压出现跳变，从而抑制由于功率放大器的输出端的电压的变化导致的爆破音。
可选的，所述外挂电容的容值大于预设电容阈值。
其中，外挂电容的容值大于预设电容阈值可以保证缓冲模块输出至功率放大器的输出端的电压平稳变化，从而抑制由于功率放大器的输出端的电压的变化导致的爆破音。
可选的，所述音频播放电路还包括数模转换器，所述数模转换器的输入端连接所述控制器的输出端，所述数模转换器的输出端连接所述功率放大器的输入端，所述数模转换器的供电端连接所述电源模块的输出端；
所述数模转换器用于将所述控制器输出的数字音频信号转换为模拟音频信号并输出至所述功率放大器。
可选的，当所述电源模块工作时，所述电源模块输出的所述直流供电电压从零变为所述目标电压值的过程中的电压变化率小于预设变化率阈值。
其中，电源模块输出的直流供电电压并不是从零跳变至最终的目标电压值，而是有一个缓慢的上升过程，避免电源模块输出的电压突变导致爆破音抑制电路来不及反应而影响爆破音抑制电路的爆破音抑制效果。
本发明实施例第二方面提供了一种音频播放设备，包括本发明实施例第一方面所述的爆破音抑制电路。
本发明实施例第三方面提供了一种音频播放电路，包括电源模块，功率放大器，耦合电容，以及爆破音抑制电路，
所述功率放大器用于接收模拟信号，将所述模拟信号放大后通过所述耦合电容输出至外放设备；
所述电源模块用于为所述功率放大器以及所述爆破音抑制电路提供工作电压；
所述耦合电容的两端分别连接所述功率放大器的输出端和所述外放设备的输入端；
所述爆破音抑制电路用于在所述工作电压超过阈值时，将所述耦合电容的一端接地。
其中，耦合电容的一端可以是耦合电容的第一端，也可以是耦合电容的第二端。爆破音抑制电路可以在工作电压超过阈值时，将功率放大器的输出端或者外放设备的输入端接 地。防止电源模块在上电过程中功率放大器的输出端出现的电平跳变通过耦合电容耦合到外放设备上产生爆破音，从而可以抑制电源模块在上电过程中产生的爆破音。
通过实施本发明实施例，当电源模块输出的直流电压上升至第一电压阈值时，爆破音抑制电路开始工作，并且将爆破音抑制电路的输出端接地，从而将耦合电容的第一端接地。在电源模块的上电过程中，爆破音抑制电路在功率放大器未开始工作时将功率放大器的输出端接地，防止电源模块在上电过程中功率放大器的输出端出现电平跳变，进而防止该电平跳变通过耦合电容耦合到负载上产生爆破音，从而可以抑制电源模块在上电过程中产生的爆破音。
附图说明
为了更清楚地说明本发明实施例或背景技术中的技术方案，下面将对本发明实施例或背景技术中所需要使用的附图进行说明。
图1是本发明实施例公开的一种音频播放电路的结构示意图；
图2是本发明实施例公开的另一种音频播放电路的结构示意图；
图3是本发明实施例公开的另一种音频播放电路的结构示意图；
图4是本发明实施例公开的另一种音频播放电路的结构示意图；
图5是本发明实施例公开的另一种音频播放电路的结构示意图；
图6是本发明实施例公开的另一种音频播放电路的结构示意图；
图7是本发明实施例公开的另一种音频播放电路的结构示意图。
具体实施方式
下面结合本发明实施例中的附图对本发明实施例进行描述。
请参见图1，图1是本发明实施例公开的一种音频播放电路的结构示意图。如图1所示，该音频播放电路可以包括电源模块11、功率放大器12、耦合电容C1以及负载13。电源模块11的输出端连接功率放大器12的供电端，功率放大器12的输入端接入模拟音频信号，功率放大器12的输出端连接耦合电容C1的第一端，耦合电容C1的第二端连接负载13的正极，负载13的负极接地。功率放大器12将接收到的模拟音频信号进行放大并将放大后的模拟音频信号通过耦合电容C1输出至负载13。本发明实施例中述及的电源模块11可以为单电源模块。其中，单电源模块，是只有正电源或者负电源的电源模块，只能输出正电压或负电压，与双电压模块能够输出正电压和负电压不同。例如，如果单电源模块的标称电压为5V，输出的电压范围为0-5V；如果双电压模块的标称电压为±5V，输出的电压范围为-5-﹢5V。
本发明实施例中，负载13为交流负载，负载13可以由交流信号进行驱动。耦合电容C1用于隔离功率放大器12输出的直流信号，避免负载13上出现直流信号对负载13造成干扰。具体的，负载13可以为喇叭或者扬声器。模拟音频信号可以由模拟信号产生器(例如，数模转换器)输入。电源模块11可以为功率放大器12提供直流供电电压。假定电源模块11提供的直流供电电压从0-VDD，其中，VDD为电源模块11能输出的最大电压。当电源模块11上电之前，功率放大器12的输出节点为靠近0的不定电平，当电源模块11上 电完成后，并且功率放大器12未接收音频模拟信号时，功率放大器12的输出节点受电源模块11的影响输出为0-VDD之间的不定电平。当不采用本发明实施例中的爆破音抑制电路时，在电源模块11上电前后，功率放大器12的输出节点会存在不定电平的跳变，而这种跳变容易通过耦合电容C1传递到负载13，从而产生爆破音。爆破音也可以称为pop音或者杂音。
请参见图2，图2是本发明实施例公开的另一种音频播放电路的结构示意图。图2是在图1的基础上为了抑制爆破音而设计的一种音频播放电路，如图2所示，该音频播放电路除了包括图1的所有模块之外，还包括爆破音抑制电路200，其中：
功率放大器12的输出端121连接耦合电容C1的第一端以及爆破音抑制电路200的输出端201，耦合电容C1的第二端连接负载13，电源模块11的输出端111连接功率放大器12的供电端以及爆破音抑制电路200的供电端；电源模块11用于为功率放大器12和爆破音抑制电路200提供直流供电电压；
爆破音抑制电路200用于当直流供电电压低于第一电压阈值时，将耦合电容C1的第一端与地端GND断开连接，第一电压阈值低于功率放大器12的工作电压阈值；
爆破音抑制电路200还用于当直流供电电压上升至第一电压阈值时，将耦合电容C1的第一端与地端连接。
本发明实施例中，电源模块11上电后，电源模块11输出的供电电压从0开始上升，当电源模块11输出的供电电压上升至VDD并保持稳定，即为电源模块11上电完成。其中，爆破音抑制电路200能够工作的最低电压阈值为第一电压阈值。当电源模块11输出的供电电压小于第一电压阈值时，由于电源模块11输出的供电电压较小，功率放大器12的输出端121输出为靠近0的幅度波动很小的不定电平，这种靠近0的幅度波动很小的不定电平即使通过耦合电容C1传递到负载13，也不会产生爆破音。因此，在电源模块11输出的供电电压低于第一电压阈值时，爆破音抑制电路200不工作，不需要将电容C1接地，可以节省功耗。
当电源模块11输出的供电电压上升至第一电压阈值之后，电源模块11输出的供电电压输出的不定电平的幅度波动较大，可能会通过耦合电容C1传递到负载13，从而产生爆破音。本发明实施例在电源模块11输出的供电电压达到第一电压阈值，即爆破音抑制电路200能够工作的最低电压阈值时，爆破音抑制电路200即可开始工作，将耦合电容C1的第一端与地端GND连接，可以在电源模块11上电完成后，并且功率放大器12未开始工作时，防止功率放大器12的输出端121的电平发生跳变，进而防止这种跳变容易通过耦合电容C1传递到负载13产生爆破音。
其中，爆破音抑制电路200可以仅包括一个开关管，也可以包括一个电容、一个电阻和一个开关管。
举例来说，当爆破音抑制电路200仅包括一个开关管时，该开关管的第一端连接地端，该开关管的第二端连接功率放大器12的输出端121，该开关管的控制端直接连接电源模块11的输出端111，其中，该开关管的开启电压为上述第一电压阈值。开关管可以是金属—氧化物—半导体(metal oxide semiconductor，MOS)场效应晶体管、绝缘栅双极型晶体管(Insulated Gate Bipolar Transistor，IGBT)、三极管等半导体开关管中的任一种。本发明实 施例中的爆破音抑制电路200仅包括一个开关管，可以节省物料成本。
当爆破音抑制电路200包括一个电容、一个电阻和一个开关管时，可以将该电容的第一端、该电阻的第一端和该开关管的控制端与电源模块11的输出端111连接，该开关管的第一端、该电容的第二端与该电阻的第二端连接地端，该开关管的第二端连接功率放大器12的输出端121，本发明实施例中的爆破音抑制电路200包括电容和电阻并联，可以在电源模块11上电时保证该开关管的控制端的电压能够缓慢上升，可以防止电源模块11的输出端111输出的电压不稳定时对该开关管造成的影响，保证爆破音抑制电路200工作的稳定性。
可选的，该音频播放电路还可以包括控制器，该控制器用于在功率放大器12进行正常的模拟信号放大之前，将耦合电容C1的第一端与地端断开连接。
本发明实施例中，为了保证功率放大器12不受音频播放电路的其他模块的影响，一般需要在音频播放电路的所有模块都上电完成并且所有模块的工作状态都稳定后，功率放大器12才开始进行正常的模拟信号放大与输出。在音频播放电路的所有模块都上电完成并且所有模块的工作状态都稳定后，并且功率放大器12进行正常的模拟信号放大之前，由于此时的功率放大器12不会受到音频播放电路的其他模块的影响而导致出现爆破音，因此，此时可以通过控制器控制耦合电容C1的第一端与地端断开连接，从而使音频播放电路恢复正常的音频播放功能。
实施图2所示的音频播放电路，采用爆破音抑制电路，让爆破音抑制电路在较低的电压下开始工作，防止电源模块在上电过程中功率放大器的输出端出现电平跳变，进而防止该电平跳变通过耦合电容耦合到负载上产生爆破音，从而可以抑制电源模块在上电过程中产生的爆破音。
可选的，请参阅图3，图3是本发明实施例公开的另一种音频播放电路的结构示意图。图3是在图2的基础上进一步优化得到的，如图3所示，音频播放电路还包括控制器14，爆破音抑制电路200包括复位模块211、触发器212、电容电阻并联模块213、电平反相器214以及第一开关管T1，复位模块211的输出端连接触发器212的复位端，触发器212的输入端连接控制器14的第一控制端141，触发器212的输出端连接电容电阻并联模块213的第一端以及电平反相器214的输入端，电平反相器214的输出端连接第一开关管T1的控制端，第一开关管T1的第一端连接功率放大器12的输出端121，第一开关管T1的第二端以及电容电阻并联模块213的第二端连接地端GND，电平反相器214的工作电压阈值等于第一电压阈值，即电平反相器214在供电电压低于第一电压阈值时无法工作，在供电电压达到第一电压阈值时开始工作。
电源模块11的输出端连接控制器14的供电端、复位模块211的供电端、触发器212的供电端以及电平反相器214的供电端；电源模块11用于为复位模块211、触发器212和电平反相器214提供直流供电电压；
电容电阻并联模块213用于当电源模块11开始工作时，向电平反相器214的输入端输入第一低电平信号；
电平反相器214用于当直流供电电压上升至第一电压阈值时，根据第一低电平信号输出第一高电平信号至第一开关管T1的控制端，第一高电平信号用于控制第一开关管T1导 通。
可选的，复位模块211的工作电压阈值为第二电压阈值，触发器212的工作电压阈值为第三电压阈值，控制器14的工作电压阈值小于第二电压阈值，第二电压阈值大于第一电压阈值，第二电压阈值小于或等于第三电压阈值；
复位模块211用于当直流供电电压上升至第二电压阈值时，向触发器212发送复位信号；
控制器14用于当直流供电电压上升至第二电压阈值时，通过第一控制端141输出第二低电平信号至触发器212的输入端；
触发器212用于当直流供电电压上升至第三电压阈值时，根据复位信号以及第二低电平信号输出第二低电平信号至电平反相器214的输入端；
电平反相器214还用于根据第二低电平信号输出第二高电平信号至第一开关管T1的控制端，第二高电平信号用于控制第一开关管T1导通。
本发明实施例中，电容电阻并联模块213由下拉电阻R1和电容C2并联而成，可以防止电平反相器214输入的电平快速变化。电平反相器214用于将输入的低电平转换为高电平输出，以及用于将输入的高电平转换为低电平输出。
由于电平反相器214、复位模块211以及触发器212的硬件特性不同，电平反相器214可以在较低的工作电压阈值下工作，而触发器212需要在相对较高的工作电压阈值下工作。例如，在一个可能的实现方式中，电平反相器的工作电压阈值为0.7V，复位模块211的工作电压阈值为1.2V，触发器212的工作电压阈值为1.4V。
在电源模块11的供电电压小于第一电压阈值时，电平反相器214、复位模块211以及触发器212均未开始工作。此时，电平反相器214、复位模块211以及触发器212的输出为靠近0的不定电平，电容电阻并联模块213可以将触发器212输出的不定电平拉至地电平，防止触发器212在上电过程中输出的不定态耦合至电平反相器214的输入端，保证在电源模块11上电后且触发器212未开始工作时，电平反相器214的输入端的信号为低电平信号且不会发生跳变。
在电源模块11的供电电压大于第一电压阈值且小于第二电压阈值时，电平反相器214开始工作，复位模块211与触发器212无法工作。此时，由于电平反相器214的输入端的信号为低电平信号且不会发生跳变，电平反相器214输出稳定的高电平信号，保证第一开关管T1稳定在导通状态，从而保证耦合电容C1的第一端拉至地电平。
在电源模块11的供电电压大于第二电压阈值且小于第三电压阈值时，电平反相器214继续工作，复位模块211开始工作，触发器212无法工作。由于触发器212需要在复位模块211的复位信号下工作，在触发器212工作之前让复位模块211开始工作，可以为触发器212工作做好准备。
在电源模块11的供电电压大于第三电压阈值时，电平反相器214与复位模块211继续工作，触发器212开始工作。触发器212开始工作后，触发器212根据复位模块211输入的复位信号、时钟发生器输入的时钟信号以及控制器14输入的低电平信号输出低电平信号至电平反相器214的输入端，电平反相器214根据输入的低电平信号输出高电平信号至第一开关管T1，以使第一开关管T1导通，从而继续将耦合电容C1的第一端拉至地电平。
在音频播放电路的所有模块都上电完成并且所有模块的工作状态都稳定后，并且功率放大器12进行正常的模拟信号放大之前，控制器14用于控制触发器212根据复位模块211输入的复位信号、时钟发生器输入的时钟信号以及控制器14输入的高电平信号输出高电平信号至电平反相器214的输入端，电平反相器214根据输入的高电平信号输出低电平信号至第一开关管T1，以使第一开关管T1关断，从而将耦合电容C1的第一端与地端断开连接。与电容电阻并联模块213相比，触发器212输出至电平反相器214的低电平信号的可控性更高，可以在电源模块11上电过程中进一步保证爆破音抑制电路200工作的稳定性。
本发明实施例中，由于触发器212可以通过时钟信号以及控制器14来实现对第一开关管T1精准的控制，从而可以精准的控制耦合电容C1的第一端与地端连接或断开，从而实现对爆破音的精准抑制。
其中，触发器212可以是D触发器、RS触发器等。图3以及后续附图中的触发器以D触发器为例进行说明。
本发明实施例中，电平反相器214的工作电压阈值最低，低于复位模块211和触发器212的工作电压阈值。在电源模块11上电且电平反相器214开始工作后，通过控制器14和复位模块211控制触发器212开始工作，以使触发器212输出低电平信号至电平反相器214的输入端，保证电平反相器214继续输出能够将第一开关管T1导通的高电平信号。与电容电阻并联模块213相比，触发器212输出至电平反相器214的低电平信号的可控性更高，可以在电源模块11上电过程中进一步爆破音抑制电路200工作的稳定性。
可选的，请参阅图4，图4是本发明实施例公开的另一种音频播放电路的结构示意图。图4是在图3的基础上进一步优化得到的，如图4所示，该爆破音抑制电路200还包括共模电压产生模块22，共模电压产生模块22的输出端220连接功率放大器12的输出端121，电源模块11的输出端连接共模电压产生模块22的供电端；
控制器14还用于当直流供电电压处于上升阶段时，控制共模电压产生模块22的输出端220与地端断开连接；
控制器14还用于当直流供电电压稳定至目标电压值时，控制共模电压产生模块22块的输出端220与地端连接。
本发明实施例中，电源模块11在上电过程中，其输出的直流供电电压会从0开始逐渐上升至目标电压值。举例来说，目标电压值可以是3.3V。共模电压产生模块22在直流供电电压处于上升阶段时，也即电源模块11在上电过程中时，为了节省功耗，让共模电压产生模块22无法工作，共模电压产生模块22的输出端220与地端GND断开连接，共模电压产生模块22的输出端220的电平为靠近0的不定电平。当直流供电电压稳定至目标电压值时，也即电源模块11在上电完成后，共模电压产生模块22可开始工作，将共模电压产生模块22的输出端220与地端GND连接。爆破音抑制电路200可以在单电源模块11上电过程中通过复位模块211、触发器212、电容电阻并联模块213、电平反相器214以及第一开关管T1将耦合电容C1的第一端接地；爆破音抑制电路200可以在单电源模块11上电完成后进一步通过共模电压产生模块22将耦合电容C1的第一端接地。可以在电源模块11上电完成后、共模电压建立之前，保证耦合电容C1的第一端始终接地，从而可以抑制在电源模块11上电完成后共模电压建立的过程中可能产生的爆破音。
共模电压产生模块22可以仅包括一个开关管，也可以包括一个电容、一个电阻和一个开关管。
举例来说，当共模电压产生模块22仅包括一个开关管时，该开关管的第一端连接地端，该开关管的第二端连接功率放大器12的输出端121，该开关管的控制端直接连接电源模块11的输出端111，其中，该开关管的开启电压为上述第二电压阈值。开关管可以是金属—氧化物—半导体场效应晶体管、绝缘栅双极型晶体管、三极管等半导体开关管。本发明实施例中的共模电压产生模块22仅包括一个开关管，可以节省物料成本。
当共模电压产生模块22包括一个电容、一个电阻和一个开关管时，可以将该电容的第一端、该电阻的第一端和该开关管的控制端与电源模块11的输出端111连接，该开关管的第一端、该电容的第二端与该电阻的第二端连接地端，该开关管的第二端连接功率放大器12的输出端121，本发明实施例中的共模电压产生模块22包括电容和电阻并联，可以在电源模块11上电时保证该开关管的控制端的电压能够缓慢上升，可以防止电源模块11的输出端111输出的电压不稳定时对该开关管造成的影响，保证共模电压产生模块22工作的稳定性。
实施图4所示的爆破音抑制电路，采用共模电压产生模块，可以在电源模块上电完成后、共模电压建立之前，保证功率放大器的输出端始终接地，从而可以抑制在电源模块11上电完成后共模电压建立的过程中可能产生的爆破音。
可选的，请参阅图5，图5是本发明实施例公开的另一种爆音频播放电路的结构示意图。图5是在图4的基础上进一步优化得到的，如图5所示，共模电压产生模块22包括参考电压产生模块221、外挂电容C3、缓冲模块222以及第二开关管T2，电源模块11的输出端连接参考电压产生模块221的供电端以及缓冲模块222的供电端；电源模块11用于为参考电压产生模块221以及缓冲模块222提供直流供电电压；参考电压产生模块221的输出端连接外挂电容C3的第一端以及缓冲模块222的输入端，缓冲模块222的输出端连接第二开关管T2的第一端，第二开关管T2的第二端连接功率放大器12的输出端121，第二开关管T2的控制端连接控制器14的第二控制端142，控制器14的第三控制端143连接参考电压产生模块221的控制端，控制器14的第四控制端144连接缓冲模块222的控制端，外挂电容C3的第二端连接地端；
控制器14用于当直流供电电压稳定至目标电压值时，通过第二控制端142输出第二控制信号至第二开关管T2的控制端，通过第三控制端输出第三控制信号至参考电压产生模块221的控制端，通过第四控制端输出第四控制信号至缓冲模块222的控制端，其中，第二控制信号用于控制第二开关管T2导通，第三控制信号用于控制参考电压产生模块221停止工作，第四控制信号用于控制缓冲模块222开始工作。
本发明实施例中，共模电压产生模块22用于抑制由于共模电压建立导致的爆破音。在电源模块11上电完成后、共模电压建立之前，控制器14控制参考电压产生模块221停止工作，控制缓冲模块222工作。由于参考电压产生模块221在停止工作时输出的电压为零，参考电压产生模块221在停止工作时输出的零电压可以通过缓冲模块222输出至功率放大器12的输出端121，保证耦合电容C1的第一端始终处于接地状态，从而可以抑制在电源模块11上电完成后可能产生的爆破音。由于参考电压产生模块221没有电流驱动能力，无 法直接驱动功率放大器12的输出端21，因此，增加缓冲模块222是为了使参考电压产生模块221产生的参考电压能够驱动功率放大器12的输出端121。
其中，参考电压产生模块221与外挂电容C3用于提供低噪声的电压基准。
可选的，控制器14还用于当第二开关管T2导通之后，通过第一控制端141输出第三高电平信号至触发器212的输入端；
触发器212还用于将第三高电平信号输出至电平反相器214的输入端；
电平反相器214还用于根据第三高电平信号输出第三低电平信号至第一开关管T1的控制端，第三低电平信号用于控制第一开关管T1关断。
其中，共模电压也可以称为参考电压、基准电压，是为了提供一个电压基准。在电源模块11上电完成后、共模电压建立之前，由于电源模块11已完成上电，为了在功率放大器12的输出端121建立共模电压，通过控制器14将第一开关管T1关断，避免第一开关管T1开启后影响功率放大器12的输出端121建立共模电压。
可选的，控制器14还用于当第二开关管T2导通，并且第一开关管T1关断之后，通过第三控制端143输出第五控制信号至参考电压产生模块221的控制端，第五控制信号221用于控制参考电压产生模块221开始工作。
其中，参考电压产生模块221开始工作时，由于有外挂电容C3的存在，参考电压产生模块221输出的参考电压会缓慢上升至最终的参考电压值，缓冲模块222也将缓慢上升的参考电压输出至功率放大器12的输出端121，以驱动功率放大器12的输出端121的电压为最终的参考电压值，从而实现在功率放大器12的输出端121建立共模电压。在建立共模电压的过程中，由于外挂电容C3的存在，功率放大器12的输出端121的电压是缓慢上升的，并不会发生突变，从而可以抑制在共模电压建立过程中可能产生的爆破音。当功率放大器12的输出端121的共模电压建立之后，功率放大器12开始工作时，由于功率放大器12的输入为零，则功率放大器12刚开始输出的电压也是共模电压，也不会导致功率放大器12的输出端121的电压出现跳变，从而抑制由于功率放大器12刚开始工作时可能产生的爆破音。本发明实施例将参考电压产生模块221、外挂电容C3与缓冲模块222配合使用，用于实现共模电压从0缓慢爬坡到最终的参考电压值。
可选的，外挂电容C3的容值大于预设电容阈值。设置尽可能大的外挂电容，可以保证参考电压产生模块221产生的参考电压的稳定性，不易发生波动。
下面结合图5来阐述爆破音抑制电路200的工作原理过程。
(1)、在电源模块11未上电时，所有电路模块都无法工作，功率放大器12的输出端121为靠近0电平的不定态。
(2)、电源模块11开始上电时，电源模块11输出的直流供电电压逐渐上升，当电源模块11输出的直流供电电压低于第一电压阈值时，爆破音抑制电路200中的复位模块211、触发器212以及电平反相器214都无法工作，触发器212的输出端为不定电平，这种不定电平通过电容电阻并联模块213后被电容电阻并联模块213中的下拉电阻R1拉至地电平，因此，电平反相器214的输入端为零电平。此时所有电路模块都无法工作，但是这些模块的输出端为靠近0电平的不定态。
(3)、电源模块11继续上电，当电源模块11输出的电压VDD达到电平反相器214 的工作电压阈值(第一电压阈值)时，爆破音抑制电路200开始工作，电平反相器214根据输入的零电平输出高电平至第一开关管T1，以使第一开关管T1导通，通过第一开关管T1将功率放大器12的输出端121拉至地电平。
(4)、电源模块11继续上电，当电源模块11输出的电压VDD达到触发器212的工作电压阈值(第三电压阈值)时，控制器14、复位模块211以及触发器212开始工作，触发器212根据复位模块211输入的复位信号以及控制器14输入的低电平信号输出低电平信号至电平反相器214的输入端，电平反相器214根据输入的低电平信号输出高电平信号至第一开关管T1，以使第一开关管T1导通，从而继续将功率放大器12的输出端121拉至地电平。
(5)、电源模块11输出的电压VDD继续上升，直至上电完成。电源模块11上电完成后，控制器14开启缓冲模块222，关闭参考电压产生模块221，此时参考电压产生模块221输出为0，同时，控制器14控制第二开关管T2导通，通过第二开关管T2将功率放大器12的输出端121拉至地电平。此时，功率放大器12的输出端121同时被第一开关管T1和第二开关管T2拉至地电平(即，0电平)，故功率放大器12的输出端121不会发生电平跳变。
(6)、当第二开关管T2导通之后，控制器14的第一控制端141输出高电平信号，以使第一开关管T1关断，在电源模块11上电的过程中，耦合电容C1的第一端始终维持在地电平，故功率放大器12的输出端121不会发生电平跳变，在电源模块11上电的过程中不会产生爆破音。
(7)、当第二开关管T2导通，并且第一开关管T1关断之后，控制器14控制参考电压产生模块221开始工作，由于有外挂电容C3的存在，参考电压产生模块221输出的参考电压会缓慢上升至最终的参考电压值，缓冲模块222也将缓慢上升的参考电压输出至功率放大器12的输出端121，以驱动功率放大器12的输出端121的电压为最终的参考电压值，从而实现在功率放大器12的输出端121建立共模电压。在建立共模电压的过程中，功率放大器12的输出端121的电压是缓慢上升的，并不会发生突变，从而可以抑制在共模电压建立过程中可能产生的爆破音。当功率放大器12的输出端121的共模电压建立之后，功率放大器12开始工作时，由于功率放大器12的输入为零，则功率放大器12刚开始输出的电压也是共模电压，也不会导致功率放大器12的输出端121的电压出现跳变，从而抑制由于功率放大器12的输出端121的电压的变化导致的爆破音。
可选的，请参阅图6，图6是本发明实施例公开的另一种音频播放电路的结构示意图。音频播放电路还包括数模转换器15，数模转换器15的输入端连接控制器14的输出端，数模转换器15的输出端连接功率放大器12的输入端，数模转换器15的供电端连接电源模块11的输出端；
数模转换器15用于将控制器14输出的数字音频信号转换为模拟音频信号并输出至功率放大器12。
本发明实施例中，控制器14可以将数字音频信号输出至数模转换器15，数模转换器15将数字音频信号转换为模拟音频信号并输出至功率放大器12，然后在通过功率放大器12对模拟音频信号进行放大并输出至负载13。
可选的，当电源模块11工作时，电源模块11输出的直流供电电压从零变为目标电压值的过程中的电压变化率小于预设变化率阈值。
其中，电源模块11输出的直流供电电压并不是从零跳变至最终的稳定电压值，而是有一个缓慢的上升过程，避免电源模块11输出的电压突变导致爆破音抑制电路20021来不及反应而影响爆破音抑制电路200的爆破音抑制效果。
可选的，请参阅图7，图7是本发明实施例公开的另一种音频播放电路的结构示意图。该音频播放电路包括电源模块11，功率放大器12，耦合电容C1、外放设备30，以及爆破音抑制电路200。
功率放大器12用于接收模拟信号，将模拟信号放大后通过耦合电容C1输出至外放设备30；
电源模块11用于为功率放大器12和爆破音抑制电路200提供工作电压；
耦合电容C1的两端分别连接功率放大器12的输出端121和外放设备30的输入端301；
爆破音抑制电路200用于在工作电压超过阈值时，将耦合电容C1的一端接地。
本发明实施例中，耦合电容C1的一端可以是耦合电容C1的第一端，也可以是耦合电容C1的第二端。爆破音抑制电路200可以在工作电压超过阈值时，将功率放大器12的输出端121或者外放设备30的输入端301接地。
实施图7所示的音频播放电路，爆破音抑制电路200可以在电源模块11输出的工作电压超过阈值时，将耦合电容C1的一端接地，防止电源模块11在上电过程中功率放大器12的输出端出现的电平跳变通过耦合电容C1耦合到外放设备30上产生爆破音，从而可以抑制电源模块11在上电过程中产生的爆破音。
本发明实施例还公开一种音频播放设备，该音频播放设备可以包括图2至图6中任一附图所示的音频播放电路。
需要说明的是，本发明实施例中提及的术语“第一”、“第二”、“第三”、“第四”、“第五”等是用于区别不同对象，而不是用于描述特定顺序。
本发明实施例中的音频播放电路可以用于手机、平板电脑等移动终端，也可以应用于音箱、电视播放机等音频播放设备。本发明实施例中的控制器14可以是音频播放设备中的微控制单元(Microcontroller Unit；MCU)，也可以是移动终端中的应用处理器(Application Processor，AP)。
综上所述，通过实施本发明实施，在电源模块的上电过程中，低压工作模块在功率放大器未开始工作时将功率放大器的输出端接地，防止电源模块在上电过程中功率放大器的输出端出现电平跳变，进而防止该电平跳变通过耦合电容耦合到负载上产生爆破音，从而可以抑制电源模块在上电过程中产生的爆破音。

Claims (11)

  1. 一种音频播放电路，其特征在于，包括电源模块、功率放大器、耦合电容、负载以及爆破音抑制电路，其中：
    所述功率放大器的输出端连接所述耦合电容的第一端以及所述爆破音抑制电路的输出端，所述耦合电容的第二端连接所述负载，所述电源模块的输出端连接所述功率放大器的供电端以及所述爆破音抑制电路的供电端；所述电源模块用于为所述功率放大器和所述爆破音抑制电路提供直流供电电压；
    所述爆破音抑制电路用于当所述直流供电电压低于第一电压阈值时，将所述耦合电容的第一端与地端断开连接，所述第一电压阈值低于所述功率放大器的工作电压阈值；
    所述爆破音抑制电路还用于当所述直流供电电压上升至所述第一电压阈值时，将所述耦合电容的第一端与所述地端连接。
  2. 根据权利要求1所述的音频播放电路，其特征在于，所述音频播放电路还包括控制器，所述爆破音抑制电路包括复位模块、触发器、电容电阻并联模块、电平反相器以及第一开关管，所述复位模块的输出端连接所述触发器的复位端，所述触发器的输入端连接所述控制器的第一控制端，所述触发器的输出端连接所述电容电阻并联模块的第一端以及所述电平反相器的输入端，所述电平反相器的输出端连接所述第一开关管的控制端，所述第一开关管的第一端连接所述功率放大器的输出端，所述第一开关管的第二端以及所述电容电阻并联模块的第二端连接所述地端，所述电平反相器的工作电压阈值等于所述第一电压阈值；
    所述电源模块的输出端连接所述控制器的供电端、所述复位模块的供电端、所述触发器的供电端以及所述电平反相器的供电端；所述电源模块用于为所述复位模块、所述触发器和所述电平反相器提供所述直流供电电压；
    所述电容电阻并联模块用于当所述电源模块开始工作时，向所述电平反相器的输入端输入第一低电平信号；
    所述电平反相器用于当所述直流供电电压上升至所述第一电压阈值时，根据所述第一低电平信号输出第一高电平信号至所述第一开关管的控制端，所述第一高电平信号用于控制所述第一开关管导通。
  3. 根据权利要求2所述的音频播放电路，其特征在于，所述复位模块的工作电压阈值为第二电压阈值，所述触发器的工作电压阈值为第三电压阈值，所述控制器的工作电压阈值小于所述第二电压阈值，所述第二电压阈值大于所述第一电压阈值，所述第二电压阈值小于或等于所述第三电压阈值；
    所述复位模块用于当所述直流供电电压上升至所述第二电压阈值时，向所述触发器发送复位信号；
    所述控制器用于当所述直流供电电压上升至所述第二电压阈值时，通过所述第一控制端输出第二低电平信号至所述触发器的输入端；
    所述触发器用于当所述直流供电电压上升至所述第三电压阈值时，根据所述复位信号以及所述第二低电平信号输出所述第二低电平信号至所述电平反相器的输入端；
    所述电平反相器还用于根据所述第二低电平信号输出第二高电平信号至所述第一开关管的控制端，所述第二高电平信号用于控制所述第一开关管导通。
  4. 根据权利要求2或3所述的音频播放电路，其特征在于，所述爆破音抑制电路还包括共模电压产生模块，所述共模电压产生模块的输出端连接所述功率放大器的输出端，所述电源模块的输出端连接所述共模电压产生模块的供电端；
    所述控制器还用于当所述直流供电电压处于上升阶段时，控制所述共模电压产生模块的输出端与所述地端断开连接；
    所述控制器还用于当所述直流供电电压稳定至目标电压值时，控制所述共模电压产生模块的输出端与所述地端连接。
  5. 根据权利要求4所述的音频播放电路，其特征在于，所述共模电压产生模块包括参考电压产生模块、外挂电容、缓冲模块以及第二开关管，所述电源模块的输出端连接所述参考电压产生模块的供电端以及所述缓冲模块的供电端；所述电源模块用于为所述参考电压产生模块以及所述缓冲模块提供所述直流供电电压；所述参考电压产生模块的输出端连接所述外挂电容的第一端以及所述缓冲模块的输入端，所述缓冲模块的输出端连接所述第二开关管的第一端，所述第二开关管的第二端连接所述功率放大器的输出端，所述第二开关管的控制端连接所述控制器的第二控制端，所述控制器的第三控制端连接所述参考电压产生模块的控制端，所述控制器的第四控制端连接所述缓冲模块的控制端，所述外挂电容的第二端连接所述地端；
    所述控制器还用于当所述直流供电电压稳定至所述目标电压值时，通过所述第二控制端输出第二控制信号至所述第二开关管的控制端，通过所述第三控制端输出第三控制信号至所述参考电压产生模块的控制端，通过所述第四控制端输出第四控制信号至所述缓冲模块的控制端，其中，所述第二控制信号用于控制所述第二开关管导通，所述第三控制信号用于控制所述参考电压产生模块停止工作，所述第四控制信号用于控制所述缓冲模块开始工作。
  6. 根据权利要求5所述的音频播放电路，其特征在于，
    所述控制器还用于当所述第二开关管导通之后，通过所述第一控制端输出第三高电平信号至所述触发器的输入端；
    所述触发器还用于将所述第三高电平信号输出至所述电平反相器的输入端；
    所述电平反相器还用于根据所述第三高电平信号输出第三低电平信号至所述第一开关管的控制端，所述第三低电平信号用于控制所述第一开关管关断。
  7. 根据权利要求6所述的音频播放电路，其特征在于，
    所述控制器还用于当所述第二开关管导通，并且所述第一开关管关断之后，通过所述 第三控制端输出第五控制信号至所述参考电压产生模块的控制端，所述第五控制信号用于控制所述参考电压产生模块开始工作。
  8. 根据权利要求2-7任一项所述的音频播放电路，其特征在于，所述音频播放电路还包括数模转换器，所述数模转换器的输入端连接所述控制器的输出端，所述数模转换器的输出端连接所述功率放大器的输入端，所述数模转换器的供电端连接所述电源模块的输出端；
    所述数模转换器用于将所述控制器输出的数字音频信号转换为模拟音频信号并输出至所述功率放大器。
  9. 根据权利要求4-8任一项所述的音频播放电路，其特征在于，当所述电源模块工作时，所述电源模块输出的所述直流供电电压从零变为所述目标电压值的过程中的电压变化率小于预设变化率阈值。
  10. 一种音频播放设备，其特征在于，包括如权利要求1-9任一项所述的音频播放电路。
  11. 一种音频播放电路，其特征在于，包括电源模块，功率放大器，耦合电容，以及爆破音抑制电路，
    所述功率放大器用于接收模拟信号，将所述模拟信号放大后通过所述耦合电容输出至外放设备；
    所述电源模块用于为所述功率放大器以及所述爆破音抑制电路提供工作电压；
    所述耦合电容的两端分别连接所述功率放大器的输出端和所述外放设备的输入端；
    所述爆破音抑制电路用于在所述工作电压超过阈值时，将所述耦合电容的一端接地。
PCT/CN2018/085627 2017-10-31 2018-05-04 音频播放电路以及音频播放设备 Ceased WO2019085427A1 (zh)

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