CN113347534A

CN113347534A - Control method and control circuit of audio switch of microphone

Info

Publication number: CN113347534A
Application number: CN202110568457.2A
Authority: CN
Inventors: 朱成超
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-05-25
Filing date: 2021-05-25
Publication date: 2021-09-03

Abstract

A method for controlling audio switch of microphone includes setting a sampling resistor between power supply of microphone and bias circuit, connecting input end of detection circuit to common point of sampling resistor and bias circuit, causing voltage variation of common point when microphone switch is closed, controlling audio switch behind microphone preamplifier to be closed by detection circuit according to variation so as to let output signal of microphone preamplifier be output by output circuit. The invention adopts the sampling resistor arranged between the power supply and the bias circuit, and the detection circuit acquires the current change value of the bias circuit and the sampling resistor to control the closing of the audio switch, thus not only having high sensitivity, but also avoiding the phenomenon of word falling or word biting.

Description

Control method and control circuit of audio switch of microphone

Technical Field

The present invention relates to a control method and a control circuit, and more particularly, to a control method and a control circuit for an audio switch of a microphone.

Background

For a microphone without a detection circuit and an audio switch, the output circuit always has an output no matter whether the microphone switch is closed or not, so that noise is always output. In order to solve the problem, a microphone with a detection circuit and an audio switch is provided in the prior art, as shown in fig. 1, a power supply 1060 of the circuit supplies power to a microphone circuit 1020 through a first bias resistor R10, a second bias resistor R20, a socket 1050 and a plug 1030, when the microphone switch 1010 is closed, the microphone circuit 1020 starts to operate, signals of the microphone circuit 1020 are sent to a microphone preamplifier 1080 through the plug 1030 and the socket 1050, after passing through the microphone preamplifier 1080, one signal is sent to the audio switch 1120, the other signal is sent to a wave detector 1090, output signals of the wave detector 1090 pass through a filter 1100 and then are sent to the detection circuit 1110, the detection circuit 1110 controls the audio switch 1120 to be closed or kept open according to the amplitude of input signals, and when the audio switch is closed, microphone signals can be output from the output circuit 1130. Two problems exist in this circuit, one is that because detector 1090 has dead zone voltage, when the amplitude of the output signal of microphone preamplifier 1080 is smaller than that of detector 1090, or when the amplitude of the output signal of microphone preamplifier 1080 is slightly larger than that of detector 1090, the output voltage of filter 1100 is 0 or slightly larger than 0, the input amplitude of detection circuit 1110 is small and is not enough to close audio switch 1120, so that output circuit 1130 has no output, that is, there is no output of small signal; secondly, when the microphone signal is strong, the dead zone voltage of the detector 1090 and the hysteresis characteristic of the filter 1100 cause the action of the detection circuit 1110 to be delayed, and the action of the audio switch 1120 is delayed, so that the first waveform of the microphone signal has partial deletion, namely, the phenomenon of word dropping or word biting which is frequently said.

Disclosure of Invention

In order to overcome the problems, the invention provides a control method and a control circuit for an audio switch of a microphone, which have high sensitivity and do not have the phenomenon of word falling or word biting.

The technical scheme of the invention is as follows: a sampling resistor R3 is set between the power supply and the bias circuit of the microphone, the input end of the detecting circuit is connected with the common point A of the sampling resistor R3 and the bias circuit, when the microphone switch is closed, the voltage of the common point A is changed, the detecting circuit controls the audio switch behind the microphone preamplifier to be closed according to the change, thereby the output signal of the microphone preamplifier is output through the output circuit.

As an improvement of the present invention, the bias circuit is designed to include a first bias resistor R1 and a first bias resistor R2, and the resistances of the first bias resistor R1 and the first bias resistor R2 are equal, and the microphone preamplifier is designed to be a differential amplifier, in which case, the first bias current I1 and the first bias current I2 change identically, and the first bias current I1 and the first bias current I2 change, so that the output noise of the microphone preamplifier is not increased.

The invention also provides a control circuit of the audio switch of the microphone, which comprises a power supply, wherein the power supply supplies power to the microphone circuit through the sampling resistor R3 and the bias circuit, the input end of the detection circuit is connected with the common point A of the sampling resistor R3 and the bias circuit, the output end of the detection circuit is used for controlling the audio switch behind the microphone preamplifier to be switched on or switched off, and the output circuit is connected behind the audio switch.

As an improvement of the present invention, the bias circuit includes a first bias resistor R1 and a first bias resistor R2, and the first bias resistor R1 and the first bias resistor R2 supply power to the microphone circuit through the socket and the plug.

As an improvement of the present invention, the first bias resistor R1 and the first bias resistor R2 have the same resistance, and the microphone preamplifier is a differential amplifier.

The invention adopts the structure that the sampling resistor R3 is additionally arranged between the power supply and the bias circuit, and the detection circuit acquires the current change values of the bias circuit and the sampling resistor R3 to control the closing of the audio switch, so that the sensitivity is high, and the phenomenon of word falling or word biting can not occur.

Drawings

Fig. 1 is a schematic diagram of a microphone detection circuit in the prior art.

Fig. 2 is a schematic diagram of an embodiment of the microphone detection circuit of the present invention.

Fig. 3 is a schematic diagram of another embodiment of the microphone detection circuit of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a control method of audio switch of microphone, set up a sampling resistor R3115 between power supply 106 and bias circuit 107 of the microphone, connect the input end of the detection circuit 114 with common point A of sampling resistor R3115 and bias circuit 107, when the microphone switch 101 is closed, will cause the voltage of the common point A to change inevitably, the detection circuit 114 controls the audio switch 112 after the microphone preamplifier 108 to close according to the change, thus make the output signal of the microphone preamplifier 108 output through the output circuit 113. Specifically, when the microphone switch 101 is closed, the microphone circuit 102 starts to operate, and the current flowing in the microphone circuit 102 changes, which causes the first bias current I1 and the second bias current I2 to change, because the total current I is equal to the sum of the first bias current I1 and the second bias current I2, the current flowing through the sampling resistor R3115 also changes, the voltage across the sampling resistor R3115 also changes, i.e., the voltage at the common point a changes, and the detection circuit 114 detects the voltage change at the common point a, which controls the audio switch 112 to be closed, i.e., the output circuit 113 outputs.

The method adopts the mode that the sampling resistor R3 is additionally arranged between the power supply and the biasing circuit, and the detection circuit acquires the current change values of the biasing circuit and the sampling resistor R3 to control the audio switch to be closed, so that the sensitivity is high, and the phenomenon of word falling or word biting cannot occur.

Preferably, the bias circuit 107 is configured to include a first bias resistor R1 and a first bias resistor R2, and the first bias resistor R1 and the first bias resistor R2 have equal resistance values, and the microphone preamplifier 108 is configured as a differential amplifier, in which case, the first bias current I1 and the first bias current I2 change identically, so that the change of the first bias current I1 and the first bias current I2 does not cause an increase in the output noise of the microphone preamplifier 108.

Referring to fig. 2, fig. 2 shows an embodiment of a control circuit for an audio switch of a microphone, which includes a power supply 106, the power supply 106 supplies power to a microphone circuit 102 through a sampling resistor R3115 and a bias circuit 107, an input terminal of a detection circuit 114 is connected to a common point a of the sampling resistor R3115 and the bias circuit 107, an output terminal of the detection circuit 114 is used for controlling an audio switch 112 located behind the microphone preamplifier 108 to be turned on or off, and an output circuit 113 is connected behind the audio switch 112. In the present invention, the audio switch 112 is a normally open switch (i.e. normally open state), when the microphone switch 101 is closed, the microphone circuit 102 starts to operate, the current flowing in the microphone circuit 102 will change, which will cause the first bias current I1 and the second bias current I2 to change, because the total charging I = the sum of the first bias current I1 and the second bias current I2, the current flowing through the sampling resistor R3115 will also change, the voltage across the sampling resistor R3115 will also change, that is, the voltage at the point a at the common point will change, the detection circuit 114 detects the voltage change at the common point a, the audio switch 112 is controlled to be closed, the microphone preamplifier 108 is connected to the output circuit 113, and the output circuit 113 outputs a signal.

The circuit adopts the mode that the sampling resistor R3115 is additionally arranged between the power supply and the biasing circuit, and the detection circuit acquires the current change value of the biasing circuit and the sampling resistor R3115 to control the closing of the audio switch, so that the sensitivity is high, and the phenomenon of word falling or word biting cannot occur.

Referring to fig. 3, fig. 3 shows another embodiment of a control circuit for an audio switch of a microphone, and the embodiment shown in fig. 3 has the same general structure as the embodiment shown in fig. 2, except that the bias circuit 107 includes a first bias resistor R1 and a first bias resistor R2, and the first bias resistor R1 and the first bias resistor R2 supply power to the microphone circuit 102 through the socket 105 and the plug 103. In this embodiment, the first bias resistor R1 and the first bias resistor R2 have the same resistance, and the microphone preamplifier 108 is a differential amplifier; in use, since the variations of the first bias current I1 and the first bias current I2 are the same, the variations of the first bias current I1 and the first bias current I2 do not cause an increase in the output noise of the microphone preamplifier circuit 108.

Various equivalent changes made by applying the contents of the specification and the drawings are included in the scope of the claims of the invention without departing from the idea of the invention.

Claims

1. A method for controlling an audio switch of a microphone, comprising: a sampling resistor R3 (115) is arranged between a power supply (106) of a microphone and a bias circuit (107), the input end of a detection circuit (114) is connected with a common point (A) of the sampling resistor R3 (115) and the bias circuit (107), when a microphone switch (101) is closed, the voltage of the common point (A) is changed, the detection circuit (114) controls an audio switch (112) positioned behind a microphone preamplifier (108) to be closed according to the change, and therefore the output signal of the microphone preamplifier (108) is output through an output circuit (113).

2. The method of claim 1, wherein: the bias circuit (107) is designed to comprise a first bias resistor R1 and a first bias resistor R2, the resistance values of the first bias resistor R1 and the first bias resistor R2 are equal, the microphone preamplifier (108) is designed to be a differential amplifier, at the moment, the first bias current I1 and the first bias current I2 are the same in change, and the first bias current I1 and the first bias current I2 are changed, so that the output noise of the microphone preamplifier (108) is not increased.

3. A control circuit of an audio switch of a microphone is characterized in that: the microphone detection circuit comprises a power supply (106), wherein the power supply (106) supplies power to a microphone circuit (102) through a sampling resistor R3 (115) and a bias circuit (107), the input end of a detection circuit (114) is connected with the common point (A) of the sampling resistor R3 (115) and the bias circuit (107), the output end of the detection circuit (114) is used for controlling an audio switch (112) located behind a microphone preamplifier (108) to be closed or opened, and an output circuit (113) is connected behind the audio switch (112).

4. The control circuit of an audio switch of a microphone according to claim 3, characterized in that: the bias circuit (107) comprises a first bias resistor R1 and a first bias resistor R2, the first bias resistor R1 and the first bias resistor R2 power the microphone circuit (102) through the socket (105) and the plug (103).

5. The control circuit of an audio switch of a microphone according to claim 4, characterized in that: the first bias resistor R1 and the first bias resistor R2 have equal resistance values, and the microphone preamplifier (108) is a differential amplifier.