A multi-channel switch-off muting circuit

Abstract

This utility model relates to the field of multi-channel power amplifier technology, and particularly to a multi-channel power-on / off mute circuit, including an optocoupler PC1, a resistor R1, a relay RY, transistors Q1 and Q2, a diode D1, a resistor R4, and a capacitor C1. Optocoupler PC1 is connected to one end of resistor R1, and the other end of resistor R1 is connected to the relay RY and transistor Q1. Transistor Q2 is connected to transistor Q1. One end of diode D1 is connected to one end of resistor R4, and both are connected to one end of capacitor C1. One end of transistor Q2 is connected between resistor R4 and capacitor C1. One end of optocoupler PC1 is used to connect to the SD control terminals of chips IC1 and IC2. Compared with existing technologies, this utility model's multi-channel power-on / off mute circuit eliminates the need for additional ICs and other components to achieve preset functions, and features low material costs, convenient procurement, convenient PCB design, wide application, high reliability, and high precision.

Description

[Technical Field] This utility model relates to the field of multi-channel power amplifier technology, and in particular to a multi-channel power on / off mute circuit. [Background Technology] Multi-channel amplifiers are widely used in audio systems to improve sound quality. For example, many car amplifiers use four channels connected to the front left speaker, front right speaker, rear left speaker, and rear right speaker, with a subwoofer placed in the trunk or under the seats to enhance the overall sound.

[0001] Because the human ear is not as sensitive to bass frequencies as the mid and high frequencies of the full frequency range, and in order to enhance the impact of bass, the output power of the bass channel is generally much greater than that of other channels, sometimes even several times greater.

[0002] like Figure 1 The image shown is a common 5-channel audio block diagram: From Figure 1 As can be seen, IC1 and IC2 are used for amplification of CH1-CH4 respectively, connecting to the front left speaker, front right speaker, rear left speaker, and rear right speaker. Since these four channels have the same power, they can use power amplifier chips. At the same time, the SD pin used for mute can be connected together. CH5 is used to connect the subwoofer. Because the power is relatively large, the same model chip as IC1 and IC2 cannot be used. Some solutions even lack the SD control pin. To achieve power-on / off mute, a relay needs to be added between the power amplifier output of channel CH5 and the speaker.

[0003] Achieving "silent power-on / off" in the CH5 channel relay control circuit is relatively easy. Most of them use a delay in powering the relay when the power is on, with the power supply coming out several seconds later. The relay engages to achieve silent power-on, and the relay cuts off the power in time when the power is off, achieving noiseless power-off.

[0004] The CH1-CH4 channels are controlled by the SD pin of the chip, which is active low. This means that the SD pin potential needs to change when the device is powered on or off. To achieve a power-on / power-off mute function, an MCU microcontroller detection circuit or other components could be added to form a control circuit. Upon power-on, after a delay of a few seconds, the SD pin would be pulled low to disconnect the circuit, keeping the SD pin at a high potential to achieve power-on mute. Upon power-off, the SD pin potential would be immediately pulled low to achieve power-off mute. Adding an MCU microcontroller or other components can achieve a power-on / power-off mute function, but this undoubtedly increases development difficulty and cost, and may even increase PCB design complexity due to the added components. [Utility Model Content] To overcome the above problems, this utility model proposes a multi-channel power-on / off mute circuit that can effectively solve the above problems.

[0005] The present invention provides a technical solution to solve the above-mentioned technical problems: a multi-channel power-on / off mute circuit, including an optocoupler PC1, a resistor R1, a relay RY, a transistor Q1, a transistor Q2, a diode D1, a resistor R4, and a capacitor C1. The optocoupler PC1 is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to the relay RY and the transistor Q1. The transistor Q2 is connected to the transistor Q1. One end of the diode D1 is connected to one end of the resistor R4 and then connected together to one end of the capacitor C1. One end of the transistor Q2 is connected between the resistor R4 and the capacitor C1. One end of the optocoupler PC1 is used to connect to the SD control terminals of chips IC1 and IC2. Preferably, the multi-channel power-on / off mute circuit further includes a resistor R2, one end of which is connected between transistors Q1 and Q2, and the other end of which is connected to transistor Q1 and capacitor C1 and then grounded.

[0006] Preferably, the multi-channel power-on / off mute circuit further includes a resistor R3, one end of which is connected to a transistor Q2, and the other end of which is connected to one end of a diode D1.

[0007] Preferably, the multi-channel power-on / off mute circuit further includes a resistor R5, one end of which is grounded, and the other end of which is connected to one end of a resistor R4 and then connected to +12V.

[0008] Preferably, the transistor Q1 is of model D882.

[0009] Preferably, the transistor Q2 is an MMBT5551.

[0010] Preferably, the LED terminal of the optocoupler PC1 is connected to the collector of the transistor Q1 through a resistor R1, and the transistor terminal of the optocoupler PC1 is connected to the SD control terminals of the chips IC1 and IC2.

[0011] Compared with existing technologies, this utility model's multi-channel power-on / off mute circuit achieves the function of mute during the entire device's power-on / off operation without requiring an additional MCU or other components to form a control circuit. Only two components are added: an optocoupler PC1 and a resistor R1. The optocoupler also provides isolation control, ensuring no interference between channels CH1-CH4 and CH5. Furthermore, it is cost-effective, significantly reduces development difficulty, and features a compact size and few required components. It is suitable for home, automotive, and portable audio applications, possessing wide applicability. It eliminates the need for additional ICs or other components to achieve preset functions. It features low material costs, easy procurement, convenient PCB design, wide application, high reliability, and high precision. [Attached Image Description] Figure 1This is a commonly used 5-channel block diagram in existing technology; Figure 2 This is a schematic diagram of the multi-channel power-on / off mute circuit of this utility model.

Detailed Implementation Methods

[0012] It should be noted that in this embodiment of the invention, all directional indications (such as up, down, left, right, front, back, etc.) are limited to relative positions on the specified view, rather than absolute positions.

[0013] Furthermore, in this utility model, the use of terms such as "first," "second," etc., is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0014] Please see Figure 2 The multi-channel power-on / off mute circuit of this utility model includes an optocoupler PC1, a resistor R1, a relay RY, a transistor Q1, a transistor Q2, a diode D1, a resistor R4, and a capacitor C1. The optocoupler PC1 is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to the relay RY and the transistor Q1. The transistor Q2 is connected to the transistor Q1. One end of the diode D1 is connected to one end of the resistor R4 and then connected together to one end of the capacitor C1. One end of the transistor Q2 is connected between the resistor R4 and the capacitor C1. One end of the optocoupler PC1 is used to connect to the SD control terminals of the chips IC1 and IC2 of channels CH1-CH4.

[0015] This utility model's multi-channel power-on / off mute circuit connects the relay switch between the CH5 amplifier output and the speaker. The B+ terminal is connected to the car amplifier's power input, which is a "constant power supply" terminal; voltage is present whenever a battery is connected. The +12V is a controlled voltage; +12V appears when the car amplifier is powered on and disappears when it is powered off.

[0016] The multi-channel power-on / off mute circuit of this utility model also includes a resistor R2. One end of the resistor R2 is connected between transistor Q1 and transistor Q2, and the other end of the resistor R2 is connected to transistor Q1 and capacitor C1 and then grounded.

[0017] The multi-channel power-on / off mute circuit of this utility model also includes a resistor R3, one end of which is connected to a transistor Q2, and the other end of which is connected to one end of a diode D1.

[0018] The multi-channel power-on / off mute circuit of this utility model also includes a resistor R5, one end of which is grounded, and the other end of which is connected to one end of a resistor R4 and then connected to +12V.

[0019] The transistor Q1 is a power transistor, model D882.

[0020] The transistor Q2 is a small-signal transistor, model MMBT5551.

[0021] When the amplifier is powered on, the controlled voltage +12V appears. The +12V voltage charges capacitor C1 through resistor R4. After a few seconds, the voltage at the positive terminal of capacitor C1 is sufficient to turn on transistor Q2, which in turn turns on transistor Q1. Relay RY is then energized, achieving mute when powered on. When the amplifier is powered off, the controlled voltage +12V disappears. The voltage at the positive terminal of capacitor C1 discharges rapidly through diode D1. Transistors Q2 and Q1 are cut off, and relay RY loses voltage and is released, achieving mute when powered off.

[0022] In the CH5 relay control circuit, the collector of transistor Q1 changes when the power amplifier is turned on and off. This change can be used to control the SD pins of IC1 and IC2, such as... Figure 2 As shown, resistor R1 and optocoupler PC1 have been added. The LED terminal of optocoupler PC1 is connected to the collector of transistor Q1 through resistor R1, and the transistor terminal of optocoupler PC1 is connected to the SD control terminals of chip IC1 and chip IC2.

[0023] Before the power amplifier is powered on, the SD pins of IC1 and IC2 are in a mute state because the LED terminal of optocoupler PC1 is lit. After the power amplifier is powered on, the relay RY is delayed for a few seconds before engaging, the collector of transistor Q1 is at a low potential, the LED terminal of optocoupler PC1 is not lit, and the transistor terminal of optocoupler PC1 is also not working. At this time, the SD pin turns to a high level, and IC1 and IC2 chips work, realizing power-on mute. When the relay is released, the collector of transistor Q1 is at a high potential. After current limiting by resistor R1, the LED terminal of optocoupler PC1 lights up, the transistor terminal of optocoupler PC1 works, and the potential of the SD pin is pulled low, realizing power-off mute.

[0024] Compared with existing technologies, this utility model's multi-channel power-on / off mute circuit utilizes a potential change in the low-frequency channel's "relay" power-on / off mute circuit. This potential change controls other channels, enabling them to synchronously power on / off and mute. This achieves both overall power-on / off mute with no impact noise and synchronized multi-channel operation. By changing the collector potential of transistor Q1 at the CH5 relay control terminal, the SD pins of chips IC1 and IC2 are controlled, achieving not only power-on / off mute but also ensuring that channels CH1-CH5 are synchronously in working or mute state, thus realizing multi-channel power-on / off mute functionality.

[0025] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. Any modifications, equivalent substitutions and improvements made within the concept of the present utility model should be included within the patent protection scope of the present utility model.

Claims

1. A multi-channel switch-off muting circuit, characterized by The device includes an optocoupler PC1, a resistor R1, a relay RY, a transistor Q1, a transistor Q2, a diode D1, a resistor R4, and a capacitor C1. The optocoupler PC1 is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to the relay RY and the transistor Q1. The transistor Q2 is connected to the transistor Q1. One end of the diode D1 is connected to one end of the resistor R4 and then connected together to one end of the capacitor C1. One end of the transistor Q2 is connected between the resistor R4 and the capacitor C1. One end of the optocoupler PC1 is used to connect to the SD control terminal of the chips IC1 and IC2.

2. The multi-channel switcher mute circuit of claim 1, wherein, The multi-channel power-on / off mute circuit also includes a resistor R2. One end of the resistor R2 is connected between transistors Q1 and Q2, and the other end of the resistor R2 is connected to transistor Q1 and capacitor C1 and then grounded.

3. The multi-channel switcher mute circuit of claim 1, wherein, The multi-channel power-on / off mute circuit also includes a resistor R3, one end of which is connected to a transistor Q2, and the other end of which is connected to one end of a diode D1.

4. The multi-channel switcher mute circuit of claim 1, wherein, The multi-channel power-on / off mute circuit also includes a resistor R5, one end of which is grounded, and the other end of which is connected to one end of a resistor R4 and then connected to +12V.

5. The multi-channel switcher mute circuit of claim 1, wherein, The transistor Q1 is model D882.

6. The multi-channel switcher mute circuit of claim 1, wherein, The transistor Q2 is model MMBT5551.

7. The multi-channel switcher mute circuit of claim 1, wherein, The LED terminal of the optocoupler PC1 is connected to the collector of the transistor Q1 through a resistor R1, and the transistor terminal of the optocoupler PC1 is connected to the SD control terminals of the chips IC1 and IC2.

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