Voltage control type volume control circuit

Abstract

The utility model discloses a voltage control type volume control circuit, which belongs to the technical field of electronic circuits, and comprises an effect transistor Q1 and a field effect transistor Q1 which are arranged in a signal loop, impedance between a drain electrode D and a source electrode S of the Q1 is equivalent to a variable resistor, the drain electrode D and the source electrode S of the Q1 and R1 form a signal voltage division circuit, and the voltage of a grid electrode G pin is changed, so that the volume of a volume is controlled. The impedance between the drain electrode D and the source electrode S of the Q1 changes. According to the volume control circuit, the gate G of the Q1 is connected with the sliding end 2 of the R2, the first pin and the second pin of the R2 are respectively connected with 3V voltage, the position of the sliding end 2 of the R2 is adjusted in a matched mode, the gate G of the Q1 can obtain 0-3V voltage, impedance between the drain D and the source S of the Q1 can change along with the voltage, the sliding end of the second pin of the R2 is connected with the first pin or the third pin to change the voltage of the OUT + output end, and the output voltage of the OUT + output end is changed. Therefore, the purpose of controlling the volume is achieved, and the problem that a traditional volume potentiometer makes contact with noise is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a voltage-controlled volume control circuit. Background Art

[0002] Almost all audio devices are equipped with a volume control circuit, which is an indispensable part. Consumers can adjust the volume of the audio according to different occasions and actual situations to meet the listening needs. Generally, the volume control circuit consists of a rotary or slide potentiometer, and the volume is adjusted by changing the resistance value of the sliding end.

[0003] Figure 1 For the schematic diagram of the existing volume control circuit, please refer to Figure 1 , VR1 is the volume adjustment potentiometer; when the sliding end 2 pin is adjusted to the potentiometer 3 pin, the 2 pin and the 3 pin are short-circuited, and the input signal is limited by R1 and then forms a voltage division with VR1 + R2. At this time, the potential of the 2 pin is the highest, and after being coupled by C1, it is amplified by the amplifier composed of R3, R4, R5, C2, and U1, and the volume is the largest at this time. When the sliding end 2 pin is adjusted to the potentiometer 1 pin, the 2 pin and the 1 pin are short-circuited, and the sum of the input signal limited by R1 and VR1 forms a voltage division with R2. At this time, the potential of the 2 pin is the lowest, and after being coupled by C1, it is amplified by the amplifier composed of R3, R4, R5, C2, and U1, and the volume is the smallest at this time. When VR1 is at different positions, it always forms a voltage division with R2 through the resistance value of R1 + VR1 to achieve volume control. This type of circuit structure is simple, but there is a contact resistance between the 2 pin sliding end and the 1, 3 pins, which is very easy to generate noise. This is also one of the reasons why many audio products are prone to hear noise when adjusting the volume after long-term use.

[0004] In order to solve the noise problem caused by the contact resistance of the above traditional volume adjustment potentiometer, some manufacturers have developed a "digital volume control" integrated circuit, integrating the volume control circuit part on the chip. Figure 2 For the schematic diagram of another existing volume adjustment circuit, please refer to Figure 2 , which is constructed with an integrated circuit analog potentiometer. It overcomes the shortcoming of the traditional potentiometer being prone to contact noise problems and can very conveniently meet the requirement of resistance value change in the circuit. However, it also has the disadvantage of requiring programming of a single-chip microcomputer or EEPROM. Therefore, we propose a voltage-controlled volume control circuit. Content of the Utility Model

[0005] This part of the content of the present application is used to briefly introduce the concepts, which will be described in detail in the following specific implementation part. This part of the content of the present application is not intended to identify the key features or essential features of the claimed technical solution, nor is it intended to limit the scope of the claimed technical solution.

[0006] The purpose of the present utility model is to provide a voltage-controlled volume control circuit to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above purpose, the present utility model provides the following technical solution: a voltage-controlled volume control circuit, including a field effect transistor Q1. The field effect transistor Q1 is connected in the signal circuit, and the impedance between the drain D and the source S of Q1 is equivalent to a variable resistor. The drain D and the source S of Q1 and R1 form a signal voltage division circuit, and by changing the voltage of the gate G pin, the impedance between the drain D and the source S of Q1 will change.

[0008] Further, the gate G of Q1 is connected to the sliding end 2 of R2, and the first pin and the second pin of R2 are respectively connected to a 3V voltage.

[0009] Further, by adjusting the position of the sliding end 2 of R2, the gate G of Q1 can obtain a voltage of 0 - 3V, and the impedance between the drain D and the source S of Q1 will change with this voltage.

[0010] Further, when the sliding end of the second pin of R2 is connected to the first pin, the voltage of the gate G of Q1 is the smallest. At this time, Q1 is not conducting, and the impedance between the drain D and the source S is above megohms.

[0011] Further, after the signal is voltage-divided by R1, it is basically close to the voltage of the IN+ input terminal. At this time, the voltage of the OUT+ output terminal is the highest, and the volume is at the maximum position.

[0012] Further, when the sliding end of the second pin of R2 is connected to the third pin, the voltage of the gate G of Q1 is the largest. At this time, Q1 is conducting, the impedance between the drain D and the source S is less than 1 ohm, almost short-circuited. After the signal is voltage-divided by R1, it is basically close to 0V. At this time, the voltage of the OUT+ output terminal is the lowest, and the volume is at the minimum position.

[0013] Compared with the prior art, the beneficial effects of the present utility model are:

[0014] This volume control circuit uses conventional components to achieve the "volume control" function by changing the impedance between the source S and the drain D of the field effect transistor. It is applicable to household, vehicle, and portable audio occasions, and has the characteristics of wide application. By controlling the voltage of the gate G of Q1, the impedance between the drain D and the source S changes. During the adjustment process, zero-noise adjustment can be achieved, and at the same time, there is no need to add additional components such as ICs to achieve the preset function. It has the characteristics of low required material cost, convenient procurement, convenient PCB design, wide application, high reliability, and high precision;

[0015] This volume control circuit connects the field effect transistor in parallel in the signal circuit. By changing the gate voltage of the field effect transistor, the impedance between the source and the drain of the field effect transistor changes. After voltage division, different voltages are generated in the signal circuit to achieve the characteristic that the output signal can be adjusted, thereby realizing volume control.

[0016] When this volume control circuit is applied to an audio system and the audio system has a "wired volume control" function, to reduce interference, Q1 can be placed inside the power amplifier, and R2 can be used for the external wired volume control. By simply changing the voltage at the second pin of R2, "wired volume control" can be achieved, enabling the wired control distance to reach several meters, resulting in less signal loss and higher signal fidelity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a circuit schematic diagram of an existing volume adjustment circuit;

[0018] Figure 2 is a circuit schematic diagram of another existing volume adjustment circuit;

[0019] Figure 3 is a circuit schematic diagram of the volume adjustment circuit of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Instead, these embodiments are provided to more thoroughly and completely understand the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for illustrative purposes and are not used to limit the protection scope of the present disclosure.

[0021] In addition, it should be noted that for ease of description, only parts related to the relevant invention are shown in the drawings. Without conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other.

[0022] It should be noted that the concepts such as "first" and "second" mentioned in the present disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or mutual dependence relationship of the functions performed by these devices, modules or units.

[0023] It should be noted that the modifications of "one" and "multiple" mentioned in the present disclosure are illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly stated in the context, it should be understood as "one or more".

[0024] The present disclosure will be described in detail below with reference to the drawings and in combination with the embodiments.

[0025] The present invention provides as Figure 3The voltage-controlled volume control circuit shown includes a field-effect transistor Q1. The field-effect transistor Q1 is in the signal loop, and the impedance between the drain D and the source S of Q1 is equivalent to a variable resistor. The drain D and the source S of Q1 and R1 form a signal voltage division circuit, and by changing the voltage of the gate G pin, the impedance between the drain D and the source S of Q1 will change;

[0026] To achieve zero-noise adjustment, as Figure 3 shown, in this circuit, the gate G of Q1 is connected to the sliding end 2 of R2, and the first pin and the second pin of R2 are respectively connected to a 3V voltage. By cooperating with adjusting the position of the sliding end 2 of R2, the gate G of Q1 can obtain a voltage of 0 - 3V, and the impedance between the drain D and the source S of Q1 will change with this voltage. By connecting the sliding end of the second pin of R2 to the first pin or the third pin, the voltage of the OUT+ output terminal is changed, so as to achieve the purpose of controlling the volume size. This not only overcomes the problem of contact noise of traditional volume potentiometers, but also does not require an external single-chip microcomputer like the " Figure 2 " scheme. Moreover, the cost is not high, the development difficulty is greatly reduced, and it also has the characteristics of small size and few required components.

[0027] As Figure 3 shown, by changing the position of the sliding end of the second pin of R2 between the first pin and the second pin, the gate voltage of Q1 is between conduction and cut-off, realizing variable volume. And because the potentiometer only controls the voltage, by controlling the voltage of the gate G of Q1, the impedance between the drain D and the source S changes, and zero-noise adjustment can be achieved during the adjustment process.

[0028] As Figure 3 shown, when the sliding end of the second pin of VR1 is connected to the first pin, the voltage of the gate G of Q1 grounded is the lowest. At this time, Q1 is not conducting, and the impedance between the drain D and the source S is above megohms, almost open circuit. At this time, the voltage of the OUT+ output terminal is the lowest, and the output level is at the minimum position. Using conventional components, volume control is achieved by changing the impedance between the source S and the drain D of the field-effect transistor. It has the characteristics of wide application. By controlling the voltage of the gate G of Q1, the impedance between the drain D and the source S changes, and zero-noise adjustment can be achieved during the adjustment process. At the same time, additional components such as ICs are not required to implement the preset functions, and it has the characteristics of low required material cost, convenient procurement, convenient PCB design, wide application, high reliability and high precision.

[0029] In summary, in the volume control circuit, the drain D and source S of Q1 and R1 form a signal voltage division circuit. By changing the voltage of the gate G pin, the impedance between the drain D and source S of Q1 will change. The gate G of Q1 is connected to the sliding end 2 of R2. The first pin and the second pin of R2 are respectively connected to a 3V voltage. By adjusting the position of the sliding end 2 of R2, a voltage of 0 - 3V can be obtained at the gate G of Q1. The impedance between the drain D and source S of Q1 will change with this voltage. When the sliding end of the second pin of R2 is connected to the first pin, the voltage of the gate G of Q1 is the lowest. At this time, Q1 is not conducting, and the impedance between the drain D and source S is above megohms. After voltage division with R1, it is basically close to the voltage of the IN+ input terminal. At this time, the voltage of the OUT+ output terminal is the highest, and the volume is at the maximum position. When the sliding end of the second pin of R2 is connected to the third pin, the voltage of the gate G of Q1 is the highest. At this time, Q1 is conducting, and the impedance between the drain D and source S is less than 1 ohm, almost short-circuited. After the signal is voltage-divided with R1, it is basically close to 0V. At this time, the voltage of the OUT+ output terminal is the lowest, and the volume is at the minimum position. Thus, by changing the position of the sliding end of the second pin of R2 between the first pin and the second pin, the gate voltage of Q1 is between conduction and cut-off, realizing the volume control process.

[0030] The above description is only some preferred embodiments of the present disclosure and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combination of the above technical features. It should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features having similar functions disclosed in the embodiments of the present disclosure.

Claims

1. Voltage-controlled volume control circuit, characterized in that: Including the effect tube Q1, the field effect tube Q1 is in the signal loop, and the impedance between the drain D and the source S of Q1 is equivalent to a variable resistor. The drain D and the source S of Q1 and R1 form a signal voltage divider circuit, and by changing the gate G pin voltage, the impedance between the drain D and the source S of Q1 will change.

2. The voltage-controlled volume control circuit according to claim 1, characterized in that: The gate G of Q1 is connected to the sliding terminal 2 of R2, and the first and second pins of R2 are connected to a 3V voltage respectively.

3. The voltage-controlled volume control circuit according to claim 1, characterized in that: By adjusting the position of the sliding terminal 2 of R2, the gate G of Q1 can obtain a voltage of 0-3V, and the impedance between the drain D and the source S of Q1 will change with the voltage.

4. The voltage-controlled volume control circuit according to claim 1, characterized in that: When the 2nd pin of R2 is connected to the 1st pin through sliding, the voltage of the gate G of Q1 is minimum. At this time, Q1 is not turned on, and the impedance between the drain D and the source S is above megohms.

5. The voltage-controlled volume control circuit according to claim 1, characterized in that: After the signal is divided by R1, it is basically close to the voltage of the IN+ input terminal. At this time, the voltage of the OUT+ output terminal is the highest and the volume is at the maximum position.

6. The voltage-controlled volume control circuit according to claim 1, characterized in that: When the sliding terminal of R2 pin 2 is connected to pin 3, the voltage of Q1 gate G is the largest. At this time, Q1 is turned on, and the impedance between drain D and source S is less than 1 ohm, which is almost a short circuit. After the signal is divided by R1, it is basically close to 0V. At this time, the voltage of OUT+ output terminal is the lowest, and the volume is at the minimum position.

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