CN219437144U - Shadow K preceding stage switch mute circuit - Google Patents

Abstract

A mute circuit of a shadow K front stage switch comprises a power supply circuit, a core working circuit and an audio output circuit; the core working circuit comprises an optocoupler U3, a resistor R12, a capacitor C21, a triode Q1, a triode Q3 and a triode Q4; the audio output circuit comprises an amplifier U4A, a field effect transistor Q2 and a diode D3. After the main control MCU is electrified, the OUT_MUTE inputs a high level to supply power to the optocoupler U3, the power supply +15V charges the capacitor C21 through the resistor R12, during the period, the triode Q3 is in a cut-off state because the base level is a low level, the optocoupler U3 is in a cut-off state, the triode Q1 is cut-off because the base level is a high level, the power supply-18V is output to the diode D3 to enable the diode D3 to be conducted, the field effect transistor Q2 is in a cut-off state, the audio signal is not output, and the starting-up MUTE function is realized; when the power is off, the field effect transistor Q2 is in a cut-off state, and the audio signal is not output, so that the shutdown mute function is realized.

Description

Shadow K preceding stage switch mute circuit

Technical Field

The utility model relates to the field of sound, in particular to a mute circuit of a shadow K front stage switch.

Background

In recent years, with the continuous development of electronic technology, especially three years of epidemic situation, movie theatres are greatly affected by the epidemic situation, more and more consumers choose to install a set of shadow K integrated sound system in home, the on-off mute function of a pre-processor also becomes an essential circuit, the traditional circuit is realized through the on-off of a relay, but the occupied space is larger, the sound of the relay is also generated during the on-off, the use experience of users is affected, and the cost is higher.

Disclosure of Invention

The utility model aims to solve the technical problem of providing a mute circuit of a shadow K front stage switch, which has low cost and good mute effect.

In order to solve the technical problems, the technical scheme of the utility model is as follows: a mute circuit of a shadow K front stage switch comprises a power supply circuit, a core working circuit and an audio output circuit; the core working circuit comprises an optocoupler U3, a resistor R12, a capacitor C21, a triode Q1, a triode Q3 and a triode Q4; the power supply +18V is respectively connected with the positive electrode of the capacitor C21 and the base electrode of the triode Q3 through the resistor R2, the power supply-15V is respectively connected with the negative electrode of the capacitor C21 and the emitter electrode of the triode Q3, the collector electrode of the triode Q3 is connected with the output end 3 pin of the optocoupler U3, the power supply +18V is connected with the emitter electrode of the triode Q1, the power supply +18V is respectively connected with the base electrode of the triode Q1 and the output end 4 pin of the optocoupler U3, the collector electrode of the triode Q1 is connected with the power supply-18V, the input end pin 1 of the optocoupler U3 is connected with the collector electrode of the triode Q4, and the base electrode of the triode Q4 is connected with the master control MCU; the audio output circuit comprises an amplifier U4A, a field effect transistor Q2 and a diode D3, wherein the output end of the amplifier is connected with the drain electrode of the field effect transistor Q2, the grid electrode of the field effect transistor Q2 is connected with the collector electrode of the triode Q1 through the diode D3 and a resistor R1, and the source electrode of the field effect transistor Q2 is used as an audio output end FL_OUT. The principle of the utility model is as follows: after the main control MCU is electrified, the OUT_MUTE inputs a high level to supply power to the optocoupler U3, the power supply +15V charges the capacitor C21 through the resistor R12, during the period, the triode Q3 is in a cut-off state because the base level is a low level, the optocoupler U3 is in a cut-off state, the triode Q1 is cut-off because the base level is a high level, the power supply-18V is output to the diode D3 to enable the diode D3 to be conducted, the field effect transistor Q2 is in a cut-off state, the audio signal is not output, and the starting-up MUTE function is realized; after the capacitor C21 is fully charged, the base level of the triode Q3 is conducted at a high level, the optocoupler U3 is conducted, the base level of the triode Q1 is at a low level and is in a conducting state, the power supply +18V is output to the diode D3 to enable the diode D3 to be cut off, the field effect tube Q2 is conducted, and the audio signal is normally output. When the power is off, +15V is the main power supply at the same time, the load is heavier, the power can be discharged preferentially, because the discharging speed of +/-18V is obviously lower than +/-15V, the capacitor C21 discharges the +15V load rapidly through the diode D2, the optocoupler U3 is in a cut-off state, the triode Q1 is cut-off because the base level is high level, the power supply-18V is output to the diode D3 to enable the triode Q2 to be conducted, the field effect transistor Q2 is in a cut-off state, the audio signal is not output, and the shutdown mute function is realized.

As an improvement, the power supply circuit includes a rectifier bridge D1, a voltage regulator U1 and a voltage regulator U2, where the positive output end of the rectifier bridge is connected to the positive electrode of the capacitor C4, the positive electrode of the capacitor C5 and the input end of the voltage regulator U1, the negative output end of the rectifier bridge is connected to the negative electrode of the capacitor C11, the negative electrode of the capacitor C12 and the input end of the voltage regulator U2, the output end of the voltage regulator U1 is connected to the positive electrode of the capacitor C3 and the positive electrode of the capacitor C6, the output end of the voltage regulator U2 is connected to the negative electrode of the capacitor C9 and the negative electrode of the capacitor C10, and the negative electrode of the capacitor C4, the negative electrode of the voltage regulator U1, the negative electrode of the capacitor C3, the negative electrode of the capacitor C6, the positive electrode of the capacitor C11, the positive electrode of the capacitor C12, the ground end of the voltage regulator U2, the positive electrode of the capacitor C9 and the positive electrode of the capacitor C10 are grounded; the positive electrode of the capacitor C4 is provided with +18V, the positive electrode of the capacitor C6 is provided with +15V, the negative electrode of the capacitor C11 is provided with-18V, and the negative electrode of the capacitor C10 is provided with-15V.

As an improvement, the model of the field effect transistor Q2 is 2SK209.

Compared with the prior art, the utility model has the beneficial effects that:

the mute circuit replaces the traditional relay, has lower cost, is mute when the power on/off is turned on, and does not generate sound at the moment of switching on/off the relay.

Drawings

Fig. 1 is a diagram of an application framework of a power-on mute circuit.

Fig. 2 is a power supply circuit diagram.

Fig. 3 is a core operational circuit diagram.

Fig. 4 is an audio output circuit diagram.

Fig. 5 is a schematic diagram of a power on/off mute circuit.

Detailed Description

The utility model is further described below with reference to the drawings.

As shown in fig. 1 and 5, a mute circuit of a shadow K front stage switch is connected with 8 front stage inputs to realize the on-off mute function. The shadow K front stage switch mute circuit comprises a power supply circuit, a core working circuit and an audio output circuit.

As shown in fig. 2, the power supply circuit includes a rectifier bridge D1, a voltage regulator U1, and a voltage regulator U2, where an output end of the positive electrode of the rectifier bridge is connected to the positive electrode of the capacitor C4, the positive electrode of the capacitor C5, and an input end of the voltage regulator U1, an output end of the negative electrode of the rectifier bridge is connected to the negative electrode of the capacitor C11, the negative electrode of the capacitor C12, and an input end of the voltage regulator U2, an output end of the voltage regulator U1 is connected to the positive electrode of the capacitor C3 and the positive electrode of the capacitor C6, and an output end of the voltage regulator U2 is connected to the negative electrode of the capacitor C9 and the negative electrode of the capacitor C10, and the negative electrode of the capacitor C4, the negative electrode of the voltage regulator C5, the negative electrode of the capacitor C3, the positive electrode of the capacitor C11, the positive electrode of the capacitor C12, the ground end of the voltage regulator U2, the positive electrode of the capacitor C9, and the positive electrode of the capacitor C10 are grounded; the positive electrode of the capacitor C4 is provided with +18V, the positive electrode of the capacitor C6 is provided with +15V, the negative electrode of the capacitor C11 is provided with-18V, and the negative electrode of the capacitor C10 is provided with-15V.

As shown in fig. 3, the core working circuit includes an optocoupler U3, a resistor R12, a capacitor C21, a triode Q1, a triode Q3, and a triode Q4; the power +18V is connected with the positive electrode of the capacitor C21 and the base electrode of the triode Q3 respectively through the resistor R2, the power supply-15V is connected with the negative electrode of the capacitor C21 and the emitter electrode of the triode Q3 respectively, the collector electrode of the triode Q3 is connected with the output end 3 pin of the optocoupler U3, the power supply +18V is connected with the emitter electrode of the triode Q1, the power supply +18V is connected with the base electrode of the triode Q1 and the output end 4 pin of the optocoupler U3 respectively, the collector electrode of the triode Q1 is connected with the power supply-18V, the input end pin 1 of the optocoupler U3 is connected with the collector electrode of the triode Q4, and the base electrode of the triode Q4 is connected with the master control MCU.

As shown in fig. 4, the audio output circuit includes an amplifier U4A, a field effect transistor Q2, and a diode D3; the output end of the amplifier is connected with the drain electrode of the field effect transistor Q2, the grid electrode of the field effect transistor Q2 is connected with the collector electrode of the triode Q1 through the diode D3 and the resistor R1, and the source electrode of the field effect transistor Q2 is used as an audio output end FL_OUT to be connected with the output of the front stage. The field effect transistor Q2 is a mute field effect transistor, the model is 2SK209, and the default state is on. The present embodiment has a total of 8 identical audio output circuits, outputting to 8 channels,

the principle of the utility model is as follows: after the main control MCU is electrified, the OUT_MUTE inputs a high level to supply power to the optocoupler U3, the power supply +15V charges the capacitor C21 through the resistor R12, during the period, the triode Q3 is in a cut-off state because the base level is a low level, the optocoupler U3 is in a cut-off state, the triode Q1 is cut-off because the base level is a high level, the power supply-18V is output to the diode D3 to enable the diode D3 to be conducted, the field effect transistor Q2 is in a cut-off state, the audio signal is not output, and the starting-up MUTE function is realized; after the capacitor C21 is fully charged, the base level of the triode Q3 is conducted at a high level, the optocoupler U3 is conducted, the base level of the triode Q1 is at a low level and is in a conducting state, the power supply +18V is output to the diode D3 to enable the diode D3 to be cut off, the field effect tube Q2 is conducted, and the audio signal is normally output. When the power is off, +15V is the main power supply at the same time, the load is heavier, the power can be discharged preferentially, because the discharging speed of +/-18V is obviously lower than +/-15V, the capacitor C21 discharges the +15V load rapidly through the diode D2, the optocoupler U3 is in a cut-off state, the triode Q1 is cut-off because the base level is high level, the power supply-18V is output to the diode D3 to enable the triode Q2 to be conducted, the field effect transistor Q2 is in a cut-off state, the audio signal is not output, and the shutdown mute function is realized.

Claims (3)

1. A shadow K preceding stage switch silence circuit is characterized in that: the device comprises a power supply circuit, a core working circuit and an audio output circuit; the core working circuit comprises an optocoupler U3, a resistor R12, a capacitor C21, a triode Q1, a triode Q3 and a triode Q4; the power supply +18V is respectively connected with the positive electrode of the capacitor C21 and the base electrode of the triode Q3 through the resistor R2, the power supply-15V is respectively connected with the negative electrode of the capacitor C21 and the emitter electrode of the triode Q3, the collector electrode of the triode Q3 is connected with the output end 3 pin of the optocoupler U3, the power supply +18V is connected with the emitter electrode of the triode Q1, the power supply +18V is respectively connected with the base electrode of the triode Q1 and the output end 4 pin of the optocoupler U3, the collector electrode of the triode Q1 is connected with the power supply-18V, the input end pin 1 of the optocoupler U3 is connected with the collector electrode of the triode Q4, and the base electrode of the triode Q4 is connected with the master control MCU; the audio output circuit comprises an amplifier U4A, a field effect transistor Q2 and a diode D3, wherein the output end of the amplifier is connected with the drain electrode of the field effect transistor Q2, the grid electrode of the field effect transistor Q2 is connected with the collector electrode of the triode Q1 through the diode D3 and a resistor R1, and the source electrode of the field effect transistor Q2 is used as an audio output end FL_OUT.

2. The mute circuit of claim 1, wherein: the power supply circuit comprises a rectifier bridge D1, a voltage stabilizer U1 and a voltage stabilizer U2, wherein the positive output end of the rectifier bridge is respectively connected with the positive electrode of a capacitor C4, the positive electrode of a capacitor C5 and the input end of the voltage stabilizer U1, the negative output end of the rectifier bridge is respectively connected with the negative electrode of a capacitor C11, the negative electrode of a capacitor C12 and the input end of the voltage stabilizer U2, the output end of the voltage stabilizer U1 is respectively connected with the positive electrode of a capacitor C3 and the positive electrode of a capacitor C6, the output end of the voltage stabilizer U2 is respectively connected with the negative electrode of a capacitor C9 and the negative electrode of a capacitor C10, the negative electrode of the capacitor C4, the negative electrode of the voltage stabilizer U1, the negative electrode of the capacitor C3, the negative electrode of the capacitor C6, the positive electrode of the capacitor C11, the positive electrode of the capacitor C12, the ground end of the voltage stabilizer U2, the positive electrode of the capacitor C9 and the positive electrode of the capacitor C10 are grounded; the positive electrode of the capacitor C4 is provided with +18V, the positive electrode of the capacitor C6 is provided with +15V, the negative electrode of the capacitor C11 is provided with-18V, and the negative electrode of the capacitor C10 is provided with-15V.

3. The mute circuit of claim 1, wherein: the model of the field effect transistor Q2 is 2SK209.