Power-off compensation control circuit for digital amplifier speakers with Mute or Standby function

Abstract

The present invention provides a power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function, including a voltage clamping circuit, a half-wave rectifier circuit, a power-off control circuit and an electric quantity energy storage circuit, wherein the power amplifier power input circuit is connected to the voltage clamping circuit and the power-off control circuit, the voltage clamping circuit is connected to the half-wave rectifier circuit, the half-wave rectifier circuit is connected to the power-off control circuit, the power-off control circuit is connected to the digital power amplifier circuit with the Mute or Standby function, and the electric quantity energy storage circuit is connected between the half-wave rectifier circuit and the power-off control circuit. The present invention can quickly shut down the power amplifier during the instantaneous power-off process of the power supply, and when the power supply has not completely dropped to 0V, the power amplifier has stopped working in advance, and when the current sound generated by the front-stage signal due to the power supply power-off signal interruption is sent to the power amplifier, the power amplifier has stopped working, and the speaker will not emit abnormal noises such as a popping (POPO) impact sound, thereby improving the customer's experience and satisfaction with the product.

Description

Technical Field

[0001] The invention relates to the technical field of electronic circuit design for products with speakers, and in particular to a power-off compensation control circuit for a digital power amplifier speaker with a mute or standby function. Background Art

[0002] like Figure 1 As shown in the figure, the 2nd pin of the digital power amplifier with Mute function is not added with the automatic power-off compensation control circuit but is directly controlled by AMP_3V3. The disadvantage of this technical solution is that when the power supply of the power amplifier is disconnected, the speaker will emit abnormal noises such as popping sound, which leads to poor customer experience and low satisfaction with the product. Figure 2 As shown in the figure, the existing technology does not add the framework diagram and signal flow chart of the power-off automatic compensation control circuit scheme. When the power supply of the digital power amplifier DC OUT is disconnected, the speaker transiently produces abnormal noises such as popping (POPO). Therefore, an instantaneous power-off automatic compensation control circuit is urgently needed to solve the above problem. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function, which solves the problem that when the power supply of the power amplifier is disconnected, the speaker will emit abnormal noises such as a popping sound, resulting in poor customer experience and low satisfaction with the product.

[0004] The present invention provides a power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function, comprising a voltage clamping circuit, a half-wave rectifier circuit, a power-off control circuit and an electric quantity storage circuit. The power amplifier power input circuit is connected to the voltage clamping circuit and the power-off control circuit, the voltage clamping circuit is connected to the half-wave rectifier circuit, the half-wave rectifier circuit is connected to the power-off control circuit, the power-off control circuit is connected to the digital power amplifier circuit with a Mute or Standby function, and the electric quantity storage circuit is connected between the half-wave rectifier circuit and the power-off control circuit.

[0005] Furthermore, the voltage clamping circuit includes a pull-up resistor and a pull-down resistor, one end of the pull-up resistor is connected to the power amplifier power input circuit, the other end of the pull-up resistor is connected to one end of the pull-down resistor and the half-wave rectifier circuit, and the other end of the pull-down resistor is grounded.

[0006] Furthermore, the half-wave rectifier circuit is composed of a diode, the anode of the diode is connected to the connection between the pull-up resistor and the pull-down resistor, and the cathode of the diode is connected to the power-off control circuit and the energy storage circuit.

[0007] Furthermore, the electric quantity energy storage circuit is composed of an electrolytic capacitor, the positive electrode of the electrolytic capacitor is connected between the negative electrode of the diode and the power-off control circuit, and the negative electrode of the electrolytic capacitor is grounded.

[0008] Further, the power-off control circuit includes a first transistor, a first resistor, a second resistor, a third resistor, a first capacitor, a second transistor, and a fourth resistor. The emitter of the first transistor is connected to the cathode of the diode and the positive electrode of the electrolytic capacitor, the base of the first transistor is connected to the power amplifier power input circuit via the first resistor, the collector of the first transistor is connected to the base of the second transistor via the second resistor, one end of the third resistor is connected between the second resistor and the base of the second transistor, the other end of the third resistor is grounded, one end of the first capacitor is connected between the second resistor and the base of the second transistor, the other end of the first capacitor is grounded, the emitter of the second transistor is grounded, and the collector of the second transistor is connected to the digital power amplifier circuit with Mute or Standby function via the fourth resistor.

[0009] Furthermore, the voltage difference between the emitter and the base of the first transistor is clamped at 3V.

[0010] Furthermore, the resistance of the pull-up resistor is 8.2k ohms, and the resistance of the pull-down resistor is 47k ohms.

[0011] Furthermore, the electrolytic capacitor is a 220μF / 25V electrolytic capacitor.

[0012] Furthermore, the diode is a 1N4148 voltage regulator diode.

[0013] Furthermore, the first transistor is a PNP transistor, and the second transistor is an NPN transistor.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention can quickly shut down the power amplifier during an instantaneous power failure, and when the power has not completely dropped to 0V, the power amplifier has stopped working in advance. When the current sound generated by the front-stage signal due to the interruption of the power failure signal is sent to the power amplifier, the power amplifier has stopped working, and the speaker will not emit abnormal noises such as popping impact sounds, thereby improving the customer experience and satisfaction with the product.

[0016] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 The schematic diagram of a digital power amplifier speaker with Mute or Standby function in the background technology of the present invention;

[0019] Figure 2 The digital power amplifier speaker frame and signal flow chart with Mute or Standby function in the background technology of the present invention;

[0020] Figure 3 The schematic diagram of the power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function of the present invention;

[0021] Figure 4 The present invention is a power-off compensation control circuit diagram for a digital power amplifier speaker with a Mute or Standby function;

[0022] Figure 5 The present invention is a schematic diagram of a digital power amplifier speaker with a Mute or Standby function, which adds an instantaneous power failure automatic compensation control circuit;

[0023] Figure 6 The present invention is a signaling interaction diagram of adding an instantaneous power failure automatic compensation control circuit on the basis of a digital power amplifier speaker with a Mute or Standby function. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0025] Used in power-off compensation control circuit of digital power amplifier speaker with Mute or Standby function, such as Figure 3 As shown, it includes a voltage clamping circuit, a half-wave rectifier circuit, a power-off control circuit and an energy storage circuit. The power amplifier power input circuit is connected to the voltage clamping circuit and the power-off control circuit. The voltage clamping circuit is connected to the half-wave rectifier circuit. The half-wave rectifier circuit is connected to the power-off control circuit. The power-off control circuit is connected to a digital power amplifier circuit with a Mute or Standby function. The energy storage circuit is connected between the half-wave rectifier circuit and the power-off control circuit.

[0026] like Figure 6 As shown, when the frame Figure 1 (Power amplifier power input circuit, that is, DC OUT) After disconnecting the DC power supply of the power amplifier, the voltage of signal 4 is connected to a large electrolytic capacitor for filtering. The voltage across the capacitor cannot change suddenly, so the DC OUT voltage can only drop slowly. When the voltage of signal 4 drops to a certain level, the frame Figure 4 (Power-off compensation control circuit, that is, instantaneous power-off automatic compensation control circuit) starts to work, and the output level of signal 5 controls the mute foot of the power amplifier. Figure 5 (Digital amplifier with Mute or Standby function) immediately turns off the amplifier after receiving the level sent by signal 5, and no signal is output. When the DC OUT voltage drops to 0V, the pre-stage signal 3 will bring a surge current to the amplifier at the moment of interruption, but before the DC OUT voltage has completely dropped to 0V, the amplifier has been turned off in advance, thus perfectly solving the problem of abnormal noise such as popping (POPO) caused by instantaneous power failure in the amplifier.

[0027] like Figure 4-Figure 5 As shown, the voltage clamping circuit includes a pull-up resistor R58 and a pull-down resistor R56, one end of the pull-up resistor R58 is connected to the power amplifier power input circuit, the other end of the pull-up resistor R58 is connected to one end of the pull-down resistor R56 and the half-wave rectifier circuit, and the other end of the pull-down resistor R56 is grounded.

[0028] The half-wave rectifier circuit is composed of a diode D1, the positive electrode of the diode D1 is connected to the connection between the pull-up resistor R58 and the pull-down resistor R56, and the negative electrode of the diode D1 is connected to the power-off control circuit and the energy storage circuit. The energy storage circuit is composed of an electrolytic capacitor C4, the positive electrode of the electrolytic capacitor C4 is connected between the negative electrode of the diode D1 and the power-off control circuit, and the negative electrode of the electrolytic capacitor C4 is grounded.

[0029] The power-off control circuit includes a first transistor Q4, a first resistor R59, a second resistor R76, a third resistor R57, a first capacitor C63, a second transistor Q13, and a fourth resistor R34. The first transistor Q4 is a PNP transistor, and the second transistor Q13 is an NPN transistor. The emitter of the first transistor Q4 is connected to the cathode of the diode D1 and the anode of the electrolytic capacitor C4, the base of the first transistor Q4 is connected to the power amplifier power input circuit via the first resistor R59, the collector of the first transistor Q4 is connected to the base of the second transistor Q13 via the second resistor R76, one end of the third resistor R57 is connected between the second resistor R76 and the base of the second transistor Q13, the other end of the third resistor R57 is grounded, one end of the first capacitor C63 is connected between the second resistor R76 and the base of the second transistor Q13, the other end of the first capacitor C63 is grounded, the emitter of the second transistor Q13 is grounded, and the collector of the second transistor Q13 is connected to the digital power amplifier circuit with Mute or Standby function via the fourth resistor R34.

[0030] The present invention can clamp accurately, the resistance of the pull-up resistor R58 is 8.2k ohms, and the resistance of the pull-down resistor R56 is 47k ohms. The DC OUT voltage is first divided by the pull-up resistor R58 and the pull-down resistor R56 to obtain: DC OUT*(R56 / R56+R58)=20*(47 / 47+8.2)=17V, and the parameters of R56 and R58 are preferably such that the emitter and base voltage difference of the first transistor Q4 is clamped at about 3V, so that the first transistor will not be broken down and the operation is stable.

[0031] The present invention has secondary rectification and filtering, and the direct current is smoother and more stable. After the DC OUT voltage is rectified by the diode D1, it is first filtered and charged by the electrolytic capacitor C4 to store energy. The diode D1 adopts a 1N4148 voltage regulator diode, and the electrolytic capacitor C4 adopts a 220μF / 25V electrolytic capacitor. The direct current here is smoother and more stable, and will not produce voltage fluctuations due to the large ripple of the external power supply and the excessive amplitude of the power amplifier signal, thereby making the input voltage unstable, causing the power-off automatic compensation control circuit to malfunction. Once the power amplifier malfunctions, the sound will be cut off, which is a difficulty in the design of many power-off automatic compensation control circuits.

[0032] The instantaneous power failure automatic compensation control circuit of the present invention can start control quickly and immediately shut down the power amplifier. When the DC OUT voltage drops to 16V, Q4 is turned on, and the electricity stored on C4 / 220uf begins to discharge in the reverse direction to the subsequent stage compensation electricity. The discharge path is: from the emitter of Q4 to the collector to the R76 resistor, and then to the base of Q13. The base of Q13 is turned on after obtaining a high level. After Q13 is turned on, the collector voltage of Q13 is directly pulled to the ground to be a low level 0V. Since the collector of Q13 is connected to the mute control pin of the power amplifier, the mute control pin of the power amplifier is at a low level, and the power amplifier is immediately turned off without any sound output.

[0033] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. Used in power-off compensation control circuit of digital power amplifier speakers with Mute or Standby function. Features: It includes a voltage clamping circuit, a half-wave rectifier circuit, a power-off control circuit and an electric quantity energy storage circuit. The power amplifier power input circuit is connected to the voltage clamping circuit and the power-off control circuit. The voltage clamping circuit is connected to the half-wave rectifier circuit. The half-wave rectifier circuit is connected to the power-off control circuit. The power-off control circuit is connected to a digital power amplifier circuit with a mute or standby function. The electric quantity energy storage circuit is connected between the half-wave rectifier circuit and the power-off control circuit. The voltage clamping circuit includes a pull-up resistor and a pull-down resistor, one end of the pull-up resistor is connected to the power amplifier power input circuit, the other end of the pull-up resistor is connected to one end of the pull-down resistor and the half-wave rectifier circuit, and the other end of the pull-down resistor is grounded; The half-wave rectifier circuit is composed of a diode, the positive electrode of the diode is connected to the connection between the pull-up resistor and the pull-down resistor, and the negative electrode of the diode is connected to the power-off control circuit and the electric quantity energy storage circuit; The electric quantity energy storage circuit is composed of an electrolytic capacitor, the positive electrode of the electrolytic capacitor is connected between the negative electrode of the diode and the power-off control circuit, and the negative electrode of the electrolytic capacitor is grounded.

2. The power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function as claimed in claim 1, Features: The power-off control circuit includes a first transistor, a first resistor, a second resistor, a third resistor, a first capacitor, a second transistor, and a fourth resistor. The emitter of the first transistor is connected to the cathode of the diode and the anode of the electrolytic capacitor, the base of the first transistor is connected to the power amplifier power input circuit via the first resistor, the collector of the first transistor is connected to the base of the second transistor via the second resistor, one end of the third resistor is connected between the second resistor and the base of the second transistor, the other end of the third resistor is grounded, one end of the first capacitor is connected between the second resistor and the base of the second transistor, the other end of the first capacitor is grounded, the emitter of the second transistor is grounded, and the collector of the second transistor is connected to the digital power amplifier circuit with Mute or Standby function via the fourth resistor.

3. The power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function as claimed in claim 2, Features: The voltage difference between the emitter and the base of the first transistor is clamped at 3V.

4. The power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function as claimed in claim 3, Features: The resistance value of the pull-up resistor is 8.2k ohms, and the resistance value of the pull-down resistor is 47k ohms.

5. The power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function as claimed in claim 1, Features: The electrolytic capacitor is a 220μF / 25V electrolytic capacitor.

6. The power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function as claimed in claim 1, Features: The diode is a 1N4148 voltage regulator diode.

7. The power-off compensation control circuit for a digital power amplifier speaker with a Mute or Standby function as claimed in claim 2, Features: The first transistor is a PNP transistor, and the second transistor is an NPN transistor.

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