A circuit and an electric appliance for eliminating switch-on and switch-off popping sound

Abstract

The application discloses a kind of elimination switch machine blasting sound circuit and electrical equipment, elimination switch machine blasting sound circuit includes voltage detection branch, first resistance and comparison circuit, the first port of voltage detection branch is connected with power supply, the second port of voltage detection branch is grounded, the voltage output end of voltage detection branch is connected with the reference end of comparison circuit, the first port of comparison circuit is connected with power supply after first resistance, the second port of comparison circuit is grounded;Signal output end is led out between first resistance and the first port of comparison circuit and is connected with the enable end of power amplifier chip, when the voltage output end of voltage detection branch output voltage is lower than the reference voltage of comparison circuit, comparison circuit is disconnected, signal output end outputs high level, to make power amplifier chip later than audio chip start running, prior to audio chip stop running.The application avoids the output of blasting sound generated in the process of audio chip power-on or power-off, improves user experience.

Description

Technical Field

[0001] This invention relates to the field of home appliance control technology, and particularly to a circuit and electrical device for eliminating popping sounds during power-on and power-off. Background Technology

[0002] Audio output devices are often found in electrical appliances, including sound systems, which play a vital role in our lives. Almost all our auditory information comes from these devices. However, during the use of sound systems, popping sounds (abrupt noises) frequently occur, mostly during the power-on and power-off cycles, and are generally unpleasant to hear. Therefore, the presence of popping sounds significantly impacts the overall quality of electrical appliances with audio output. As consumers' spending power increases, their demands for smoother sound also rise, making the implementation and improvement of circuits to eliminate popping sounds during power-on and power-off increasingly important.

[0003] While there are many commonly used circuits for eliminating popping sounds during power-on and power-off, they generally only eliminate popping sounds when power is on or off. Furthermore, they often suffer from complex circuitry or focus solely on eliminating popping sounds during power-on or power-off, resulting in reduced cost-effectiveness and limited application value. Summary of the Invention

[0004] This invention proposes a circuit and electrical equipment to eliminate popping sounds during power-on and power-off, thereby solving the problem mentioned in the background art where electrical equipment with audio output easily produces popping sounds during power-on and power-off, affecting the overall quality of the electrical equipment.

[0005] One aspect of the present invention provides a circuit for eliminating popping sounds during power-on and power-off, comprising a voltage detection branch, a first resistor, and a comparator circuit. A first port of the voltage detection branch is connected to a power supply, a second port of the voltage detection branch is grounded, and a voltage output terminal of the voltage detection branch is connected to a reference terminal of the comparator circuit. A first port of the comparator circuit is connected to the power supply via the first resistor, and a second port of the comparator circuit is grounded. A signal output terminal is led out between the first resistor and the first port of the comparator circuit and connected to the enable terminal of a power amplifier chip. When the voltage output terminal of the voltage detection branch is lower than the reference voltage of the comparator circuit, the comparator circuit is disconnected, and the signal output terminal outputs a high level, so that the power amplifier chip starts operating later than the audio chip and stops operating before the audio chip.

[0006] Furthermore, it also includes a first capacitor and a second resistor. One end of the first capacitor is connected to the power supply, and the other end of the first capacitor is connected to the second resistor. The other end of the second resistor is grounded. A connection terminal is led out between the first capacitor and the second resistor and connected to the signal output terminal. As the voltage output by the power supply gradually rises from 0V, the charging effect of the first capacitor causes current to flow through the second resistor, and the signal output terminal outputs a high level so that the power amplifier chip starts running later than the audio chip.

[0007] Furthermore, it also includes a third resistor connected between the power supply and the first capacitor.

[0008] Furthermore, it also includes a voltage regulator circuit, which is connected between the signal output terminal and ground, and is used to clamp the output voltage of the signal output terminal to a first protection voltage.

[0009] Furthermore, the voltage regulator circuit includes a Zener diode, the cathode of which is connected to the signal output terminal, and the anode of which is grounded.

[0010] Furthermore, it also includes a fourth resistor, which is connected between the cathode of the Zener diode and the signal output terminal.

[0011] Furthermore, the voltage detection branch includes a fifth resistor and a sixth resistor. One end of the fifth resistor serves as the first port of the voltage detection branch and is connected to the power supply. The other end of the fifth resistor is connected to one end of the sixth resistor. The other end of the sixth resistor serves as the second port of the voltage detection branch and is grounded. A connection terminal is led out between the fifth resistor and the sixth resistor as the voltage output terminal of the voltage detection branch.

[0012] Furthermore, the resistance values ​​of the fifth resistor, the sixth resistor, the reference voltage of the comparator circuit, and the undervoltage level voltage of the power supply satisfy the following voltage division condition:

[0013]

[0014] Where R5 is the resistance of the fifth resistor, R6 is the resistance of the sixth resistor, V0 is the reference voltage of the comparator circuit, and V L This is the undervoltage level of the power supply.

[0015] Furthermore, the comparator circuit is a TL431 three-terminal Zener diode. The cathode of the TL431 three-terminal Zener diode is connected to the power supply as the first port of the comparator circuit, the anode of the TL431 three-terminal Zener diode is grounded as the second port of the comparator circuit, and the reference terminal of the TL431 three-terminal Zener diode is connected to the voltage output terminal of the voltage detection branch as the reference terminal of the comparator circuit.

[0016] In another aspect, the present invention provides an electrical device that includes an audio device, the audio device comprising the aforementioned circuit for eliminating popping sounds during power-on and power-off.

[0017] This invention provides a circuit and electrical device for eliminating popping sounds during power-on and power-off. The circuit includes a voltage detection branch, a first resistor, and a comparator circuit. The first port of the voltage detection branch is connected to a power supply, the second port is grounded, and the voltage output terminal of the voltage detection branch is connected to the reference terminal of the comparator circuit. The first port of the comparator circuit is connected to the power supply via the first resistor, and the second port is grounded. A signal output terminal is led out between the first resistor and the first port of the comparator circuit and connected to the enable terminal of a power amplifier chip. When the voltage output terminal of the voltage detection branch is lower than the reference voltage of the comparator circuit, the comparator circuit is disconnected, and the signal output terminal outputs a high level, causing the power amplifier chip to start operating later than the audio chip and stop operating before the audio chip. By setting up a voltage detection branch and a comparator circuit, this invention pulls the output signal of the signal output terminal to a high level during voltage rise and fall, causing the power amplifier chip to stop operating before the audio chip, thus avoiding the popping sound output generated by the audio chip during power-on or power-off, improving the user experience.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0019] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0020] Figure 1 A structural block diagram of a circuit for eliminating popping sounds during power-on and power-off is provided in one embodiment of the present invention;

[0021] Figure 2 The present invention provides a circuit diagram for eliminating popping sounds during power-on and power-off. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] The circuit for eliminating popping sounds during power-on and power-off proposed in this invention is applicable to electrical devices with audio output functions. It should be noted that since Class D amplifiers are commonly used, the power supply voltage of the amplifier chip is usually higher than that of the audio chip when the system is powered on. This causes the audio chip to power on before the amplifier chip. Therefore, it is necessary to ensure that the SD / MUTE pin of the amplifier chip is disabled, i.e., the amplifier chip is not working, to prevent the audio chip from outputting popping sounds during power-on. The SD / MUTE pin is enabled only after the bias voltage of the analog output of the audio chip stabilizes. Similarly, the SD / MUTE pin of the amplifier chip needs to be disabled before power-off to prevent the audio chip from outputting popping sounds when power is lost. Therefore, controlling the amplifier to prevent popping sounds involves controlling the power-on timing of the amplifier chip's SD / MUTE pin and the audio chip.

[0026] Based on the above principles, an embodiment of the present invention provides a circuit for eliminating popping sounds during power-on and power-off. Figure 1 The schematic diagram illustrates a structural block diagram of a circuit for eliminating popping sounds during power-on and power-off according to an embodiment of the present invention; Figure 2 The diagram schematically illustrates a circuit diagram of a power-on / off popping sound elimination circuit according to an embodiment of the present invention. Figure 1 , Figure 2 As shown in the figure, an embodiment of the present invention provides a circuit for eliminating popping sounds during power-on and power-off. The circuit includes a voltage detection branch, a first resistor R1, and a comparator circuit. The first port of the voltage detection branch is connected to a power supply, the second port of the voltage detection branch is grounded, and the voltage output terminal of the voltage detection branch is connected to the reference terminal of the comparator circuit. The first port of the comparator circuit is connected to the power supply via the first resistor R1, and the second port of the comparator circuit is grounded. A signal output terminal IO is led out between the first resistor R1 and the first port of the comparator circuit and connected to the enable terminal of a power amplifier chip. When the voltage output terminal of the voltage detection branch is lower than the reference voltage of the comparator circuit, the comparator circuit is disconnected, and the signal output terminal IO outputs a high level, causing the power amplifier chip to start running later than the audio chip and stop running before the audio chip. This invention effectively avoids the output of popping sounds from the audio chip during power-on and power-off processes by adjusting the power-on sequence of the audio chip and the power amplifier chip. Using a simple circuit structure, it achieves the purpose of eliminating popping sounds and has a very beneficial technical effect.

[0027] It should be noted that, in this embodiment of the invention, during the rise of the power supply's output voltage, the voltage detection branch can accurately reflect the changes in the power supply voltage and output a corresponding voltage control from the voltage output terminal of the voltage detection branch to control the on / off state of the comparison circuit. The comparison circuit conducts only when the power supply voltage is higher than a first preset voltage. At this time, the output voltage of the signal output terminal IO of the power-on / off pop sound elimination circuit is pulled down to a low level by the comparison circuit, and the power amplifier chip is enabled. Since the audio chip has already started operating before the power amplifier chip at this time, its pop sound is not output. Conversely, during the fall of the power supply voltage, since the power amplifier chip is already disabled when the power supply voltage drops to the first preset voltage, the pop sound generated by the audio chip during the subsequent fall of the power supply voltage will not be output.

[0028] Furthermore, the enable terminal of the power amplifier chip in this embodiment of the invention can be the MUTE pin of the power amplifier chip. The MUTE pin is not necessarily a pin with the specific letter "MUTE". Depending on the power amplifier chip, the specific name of this pin may also be different. Other similar names include SD / SHDN / EN / STB, etc. This invention does not impose any specific limitations on it.

[0029] Furthermore, in a specific embodiment of the present invention, the voltage detection branch includes a fifth resistor R5 and a sixth resistor R6. One end of the fifth resistor R5 is connected to the power supply as the first port of the voltage detection branch, and the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6. The other end of the sixth resistor R6 is grounded as the second port of the voltage detection branch. A connection terminal is led out between the fifth resistor R5 and the sixth resistor R6 as the voltage output terminal of the voltage detection branch.

[0030] Furthermore, the resistance values ​​of the fifth resistor R5, the sixth resistor R6, the reference voltage of the comparator circuit, and the undervoltage level voltage of the power supply satisfy the following voltage division condition:

[0031]

[0032] Where R5 is the resistance of the fifth resistor R5, R6 is the resistance of the sixth resistor R6, V0 is the reference voltage of the comparator circuit, V L This is the undervoltage level of the power supply.

[0033] It should be noted that, due to the high power of the amplifier chip, its operation can easily cause a voltage drop in the power supply. Therefore, in this embodiment of the invention, the resistance values ​​of the fifth resistor R5 and the sixth resistor R6 are not based on the rated voltage of the power supply, but rather on the undervoltage level of the power supply. The voltage division of the undervoltage level by the fifth resistor R5 and the sixth resistor R6 is sufficient to reach the reference voltage of the comparator circuit. The operating voltage of the audio chip is lower than the undervoltage level of the power supply.

[0034] Furthermore, in this embodiment of the invention, the comparator circuit is a TL431 Zener diode. The cathode of the TL431 Zener diode serves as the first port of the comparator circuit and is connected to the power supply. The anode of the TL431 Zener diode serves as the second port of the comparator circuit and is grounded. The reference terminal of the TL431 Zener diode serves as the reference terminal of the comparator circuit and is connected to the voltage output terminal of the voltage detection branch. The TL431 Zener diode only conducts when the voltage input to its reference terminal is higher than its own reference voltage. Therefore, the TL431 Zener diode can be used as a comparator circuit, conducting only when the power supply voltage rises to a certain value, pulling the output voltage of the signal output terminal IO down to a low level.

[0035] Furthermore, the circuit for eliminating popping sounds during power-on and power-off in this embodiment of the invention also includes a first capacitor C1 and a second resistor R2. One end of the first capacitor C1 is connected to the power supply, and the other end of the first capacitor C1 is connected to the second resistor R2. The other end of the second resistor R2 is grounded. A connection terminal is led out between the first capacitor C1 and the second resistor R2 and connected to the signal output terminal IO. As the voltage output by the power supply gradually rises from 0V, current flows through the second resistor R2 due to the charging effect of the first capacitor C1. The signal output terminal IO outputs a high level, so that the power amplifier chip starts up and runs later than the audio chip.

[0036] Furthermore, the circuit for eliminating popping sounds during power-on and power-off in this embodiment of the invention also includes a third resistor R3, which is connected between the power supply and the first capacitor C1, and serves to limit current.

[0037] Furthermore, the circuit for eliminating popping sounds during power-on and power-off in this embodiment of the invention also includes a voltage regulator circuit. The voltage regulator circuit is connected between the signal output terminal IO and ground, and is used to clamp the output voltage of the signal output terminal IO to a first protection voltage. In this embodiment of the invention, the first protection voltage is the highest voltage that the enable terminal of the power amplifier chip can accept. To protect the enable terminal of the power amplifier chip from being burned out by high voltage, this embodiment of the invention utilizes a voltage regulator circuit to clamp the output voltage of the signal output terminal IO to the first protection voltage.

[0038] In one specific embodiment of the present invention, the voltage regulator circuit includes a Zener diode D2, the cathode of which is connected to the signal output terminal IO, and the anode of which is grounded. The reverse breakdown voltage of the Zener diode D2 serves as the first protection voltage, which controls the output voltage of the signal output terminal IO to always remain below the first protection voltage when the signal output terminal IO outputs a high level.

[0039] Furthermore, the circuit for eliminating popping sounds during power-on and power-off in this embodiment of the invention also includes a fourth resistor R4, which is connected between the cathode of the Zener diode D2 and the signal output terminal IO. The fourth resistor R4 serves as a current limiter. It can limit the current flowing into the enable terminal of the power amplifier chip, further protecting the chip. In this embodiment, the fourth resistor R4 can be connected between the cathode of the Zener diode D2 and the lead-out terminals between the first capacitor C1 and the second resistor, or it can be connected to a common terminal of the leads-out terminals between the cathode of the Zener diode D2 and the first capacitor C1 and the second resistor, with the other end connected to the signal output terminal IO. This invention does not limit the connection between these connections.

[0040] The circuit for eliminating popping sounds during power-on and power-off provided in this embodiment of the invention requires only 9 simple components to achieve the effect of eliminating popping sounds during power-on and power-off. Its circuit structure is simple, its control logic is clear, and its overall cost is only about 0.4 yuan, which is very cost-effective. It can achieve the purpose of eliminating popping sounds during power-on and power-off with a relatively low cost.

[0041] In a specific embodiment of the present invention, the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are all 100kΩ, the resistance value of the fifth resistor R5 is 26kΩ, the resistance value of the sixth resistor R6 is 10kΩ, the reference voltage of the TL431 comparator is 2.5V, the power supply voltage is 12V, and the undervoltage level voltage is 9V.

[0042]

[0043] In this embodiment of the invention, during the power-on process, the power supply voltage gradually rises from 0V. When the power supply voltage reaches 5V, the audio chip is enabled. At this time, because the voltage output of the voltage detection circuit is lower than 2.5V, the enable pin of the power amplifier chip is pulled high, and the power amplifier chip is disabled, preventing the transmission of the popping sound from the audio chip. When the power supply voltage rises to 9V, the enable pin of the power amplifier chip is pulled low, and the power amplifier chip is disabled. Conversely, during the power-off process, the power supply voltage gradually decreases from 12V. When the power supply voltage drops below 9V, the enable pin of the power amplifier chip is pulled high, and the power amplifier chip is disabled. At this time, the power supply voltage continues to decrease, and the popping sound generated by the audio and video can no longer be output by the power amplifier chip. Therefore, this embodiment of the invention effectively eliminates the popping sound phenomenon during the power-on and power-off of audio equipment while maintaining a simple circuit structure and low cost, thus improving the user experience.

[0044] In addition, the present invention also provides an electrical device, which includes an audio device, the audio device including the above-mentioned circuit for eliminating popping sounds during power-on and power-off.

[0045] In this embodiment of the invention, the circuit for eliminating popping sounds during power-on and power-off is installed on the audio equipment in the electrical appliance. The circuit has a simple structure, clear control logic, and low cost of consumables. It occupies a very small space in the electrical appliance and can achieve the purpose of eliminating popping sounds during power-on and power-off. In practical applications, it has a very beneficial technical effect.

[0046] This invention provides a circuit and electrical device for eliminating popping sounds during power-on and power-off. The circuit includes a voltage detection branch, a first resistor R1, and a comparator circuit. The first port of the voltage detection branch is connected to a power supply, the second port is grounded, and the voltage output terminal of the voltage detection branch is connected to the reference terminal of the comparator circuit. The first port of the comparator circuit is connected to the power supply via the first resistor R1, and the second port is grounded. A signal output terminal IO is led out between the first resistor R1 and the first port of the comparator circuit and connected to the enable terminal of a power amplifier chip. When the voltage output terminal of the voltage detection branch is lower than the reference voltage of the comparator circuit, the comparator circuit is disconnected, and the signal output terminal IO outputs a high level, causing the power amplifier chip to start operating later than the audio chip and stop operating before the audio chip. By setting up a voltage detection branch and a comparator circuit, this invention pulls the output signal of the signal output terminal IO to a high level during voltage rise and fall, causing the power amplifier chip to stop operating before the audio chip, thus avoiding the popping sound output generated by the audio chip during power-on or power-off, improving the user experience.

[0047] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A circuit for eliminating popping sounds during power-on and power-off, characterized in that, The system includes a voltage detection branch, a first resistor, and a comparator circuit. The first port of the voltage detection branch is connected to a power supply, the second port of the voltage detection branch is grounded, and the voltage output terminal of the voltage detection branch is connected to the reference terminal of the comparator circuit. The first port of the comparator circuit is connected to the power supply via the first resistor, and the second port of the comparator circuit is grounded. A signal output terminal is led out between the first resistor and the first port of the comparator circuit and connected to the enable terminal of the power amplifier chip. When the voltage output terminal of the voltage detection branch is lower than the reference voltage of the comparator circuit, the comparator circuit is disconnected, and the signal output terminal outputs a high level, so that the power amplifier chip starts operating later than the audio chip and stops operating before the audio chip. The voltage detection branch includes a fifth resistor and a sixth resistor. One end of the fifth resistor is connected to the power supply as the first port of the voltage detection branch. The other end of the fifth resistor is connected to one end of the sixth resistor. The other end of the sixth resistor is grounded as the second port of the voltage detection branch. A connection terminal is led out between the fifth resistor and the sixth resistor as the voltage output terminal of the voltage detection branch. The resistance values ​​of the fifth resistor, the sixth resistor, the reference voltage of the comparator circuit, and the undervoltage level voltage of the power supply satisfy the following voltage division condition: ； Where R5 is the resistance value of the fifth resistor, R6 is the resistance value of the sixth resistor, V0 is the reference voltage of the comparator circuit, and VL is the undervoltage level voltage of the power supply. The comparator circuit is a TL431 three-terminal Zener diode. The cathode of the TL431 three-terminal Zener diode is connected to the power supply as the first port of the comparator circuit, the anode of the TL431 three-terminal Zener diode is grounded as the second port of the comparator circuit, and the reference terminal of the TL431 three-terminal Zener diode is connected to the voltage output terminal of the voltage detection branch as the reference terminal of the comparator circuit. It also includes a first capacitor and a second resistor. One end of the first capacitor is connected to the power supply, and the other end of the first capacitor is connected to the second resistor. The other end of the second resistor is grounded. A connection terminal is led out between the first capacitor and the second resistor and connected to the signal output terminal. As the voltage output by the power supply gradually rises from 0V, the charging effect of the first capacitor causes current to flow through the second resistor, and the signal output terminal outputs a high level so that the power amplifier chip starts up and runs later than the audio chip. It also includes a voltage regulator circuit, which is connected between the signal output terminal and ground, and is used to clamp the output voltage of the signal output terminal to a first protection voltage.

2. The circuit according to claim 1, characterized in that, It also includes a third resistor, which is connected between the power supply and the first capacitor.

3. The circuit according to claim 1, characterized in that, The voltage regulator circuit includes a Zener diode, the cathode of which is connected to the signal output terminal, and the anode of which is grounded.

4. The circuit according to claim 3, characterized in that, It also includes a fourth resistor, which is connected between the cathode of the Zener diode and the signal output terminal.

5. An electrical appliance, characterized in that, The electrical equipment includes an audio device, which includes a circuit for eliminating popping sounds during power-on and power-off as described in any one of claims 1 to 4.

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