Logarithmic amplification circuit with replaceable bottom

Abstract

The utility model relates to a logarithmic amplification circuit with a replaceable bottom. The logarithmic amplification circuit comprises a negative feedback module, a transistor module, an operation module, a voltage division module and a single-chip microcomputer module. An intelligent digital potentiometer in the voltage division module is accurately controlled through the single-chip microcomputer module, the resistance value of the intelligent digital potentiometer is dynamically adjusted to achieve real-time adjustment of the voltage division coefficient, the voltage division coefficient is dynamically optimized in combination with a feedback mechanism, and therefore accurate control over the output logarithmic function base number is flexibly achieved. Specifically, a microcontroller chip of the single-chip microcomputer module controls the resistance value of the intelligent digital potentiometer through a program, and judges whether the current base number reaches a target value or not according to a feedback signal; and if the target value is not reached, carrying out iterative optimization by adjusting the resistance value of the resistor until the target base number requirement is met. Finally, the circuit can flexibly adjust the logarithmic base number relation between the output signal and the input signal, so that the logarithmic amplifier can meet the requirements of different application scenes for base number changes, and the practicability and the application range of the logarithmic amplifier are remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic circuit and signal processing technical field, in particular to a kind of replaceable base logarithmic amplification circuit. BACKGROUND

[0002] Logarithmic amplifier is a kind of nonlinear analog amplifier, can generate the output of logarithmic function with input signal or signal envelope. Logarithmic amplifier can compress input signal with very large dynamic range into output signal with fixed amplitude range, provide high gain for low-level input signal, and gradually reduce the gain of high-level signal.

[0003] At present, logarithmic amplifier is widely used in measurement, communication and control system, can convert the amplitude of input signal into logarithmic value of output signal, provides the ability to work under wide dynamic range. According to the different working principles and circuit structures, logarithmic amplifier can be divided into three types based on diode, based on operational amplifier and based on sensor. Among them, logarithmic amplifier based on diode and operational amplifier realizes logarithmic conversion of input signal through nonlinear element and feedback circuit, and logarithmic amplifier based on sensor is often used in specific scenes such as optical or pressure sensing. Through reasonable design and optimization, logarithmic amplifier can provide high precision, good stability and dynamic range compression performance. In the field of sound measurement, optical sensing and wireless communication, logarithmic amplifier provides effective and reliable solution for processing wide dynamic range signal.

[0004] However, the current logarithmic amplifier has not realized the function of adjustable output logarithmic function base in circuit design, which leads to its inability to flexibly adapt to the characteristics of base change in different scenes in practical application. That is, the existing logarithmic amplifier has the technical problems of unadjustable output logarithmic function base and difficult to flexibly meet the needs of different application scenarios. UTILITY MODEL CONTENT

[0005] Therefore, it is necessary to provide a replaceable base logarithmic amplification circuit.

[0006] In order to achieve the above purpose, the utility model embodiment adopts the following technical scheme:

[0007] On the one hand, a replaceable base logarithmic amplification circuit is provided, comprising: a negative feedback module, a transistor module, an operation module, a voltage division module and a single-chip microcomputer module;

[0008] The input end of the negative feedback module is used to connect the input signal, and the input signal is proportionally operated and output; The input end of the transistor module is connected with the output end of the negative feedback module, the output end of the transistor module is connected with the input end of the operation module, and the transistor module is the feedback element of the negative feedback module;

[0009] The input end of the voltage division module is connected with the negative feedback module, the operation module and the single-chip microcomputer module respectively, the output end of the voltage division module is used for outputting the target signal, the single-chip microcomputer module precisely controls the intelligent digital potentiometer of the voltage division module, realizes dynamic control of the voltage division coefficient, and thus outputs the target signal; the target signal is an electrical signal in a specific logarithmic relationship with the input signal, and the logarithmic base is determined by the voltage division coefficient.

[0010] In one of the embodiments, the voltage division module further comprises a thermistor for temperature compensation of the transistor module.

[0011] In one of the embodiments, the negative feedback module comprises a first operational amplifier and a resistor; the transistor module comprises a pair of matched transistors; the operation module comprises a second operational amplifier and a precision reference voltage source; the voltage division module comprises an intelligent digital potentiometer and a thermistor; and the single-chip microcomputer module comprises a microcontroller chip and a program memory.

[0012] In one of the embodiments, the intelligent digital potentiometer is an X9C103 intelligent digital potentiometer.

[0013] In one of the embodiments, the negative feedback module comprises an operational amplifier chip of model OPA2277U.

[0014] In one of the embodiments, the operation module comprises an operational amplifier chip of model OPA2277U.

[0015] In one of the embodiments, the transistor module comprises a transistor of model BC184BP.

[0016] The one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0017] The above-described changeable-base logarithmic amplification circuit precisely controls the intelligent digital potentiometer in the voltage division module through the single-chip microcomputer module, dynamically adjusts the resistance value of the intelligent digital potentiometer to realize real-time adjustment of the voltage division coefficient, dynamically optimizes the voltage division coefficient in combination with the feedback mechanism, and thus flexibly realizes precise control of the output logarithmic function base. Specifically, the microcontroller chip of the single-chip microcomputer module controls the resistance value of the intelligent digital potentiometer through a program, and judges whether the current base reaches a target value according to a feedback signal; if the target value is not reached, the resistance value is adjusted for iterative optimization until the target base requirement is met. Finally, the circuit can flexibly adjust the logarithmic base relationship between the output signal and the input signal, so as to adapt to the demand for base change in different application scenarios, thereby significantly improving the practicability and application range of the logarithmic amplifier. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only need to be some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0019] Figure 1 The first schematic diagram of the structure of the replaceable base logarithmic amplification circuit in an embodiment;

[0020] Figure 2 The first schematic diagram of the structure of the replaceable base logarithmic amplification circuit in an embodiment;

[0021] Figure 3 The second schematic diagram of the structure of the replaceable base logarithmic amplification circuit in an embodiment;

[0022] Figure 4 The schematic diagram of the principle of the single-chip microcomputer module controlling the intelligent digital potentiometer in an embodiment;

[0023] Figure 5 The schematic diagram of the single-chip microcomputer module control process in an embodiment. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings show embodiments of the present application. However, the present application can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0026] It can be understood that the terms "first", "second", and the like used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. For example, without departing from the scope of the present application, the first resistor can be referred to as the second resistor, and similarly, the second resistor can be referred to as the first resistor. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0027] It can be understood that the "connection" in the following embodiments should be understood as "electrically connected", "communicatively connected" and the like if the circuits, modules, units and the like connected with each other have the transmission of electric signals or data. In addition, the terms such as "input end", "output end" and the like do not limit the corresponding components to have only one input end or output end, and can also have multiple input ends or output ends, and can also integrate multiple sub-input / output ports in one input / output port, and the specific determination can be made according to the port setting of the actual used component.

[0028] As used herein, the singular forms "a", "an" and "the" can include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "comprising" or "including" or "having" and the like specifies the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but does not exclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0029] The embodiments of the present application will be described in detail below with reference to the accompanying drawings of the embodiments of the present application.

[0030] In one embodiment, as Figure 1 As shown in the first schematic view of the structure of the exchangeable base logarithmic amplification circuit, the embodiment of the present application provides an exchangeable base logarithmic amplification circuit, comprising: a negative feedback module, a transistor module, an operation module, a voltage division module and a single-chip microcomputer module.

[0031] The input end of the negative feedback module is used to connect the input signal and output the proportional operation of the input signal; the input end of the transistor module is connected with the output end of the negative feedback module, the output end of the transistor module is connected with the input end of the operation module, and the transistor module is the feedback element of the negative feedback module.

[0032] The input end of the voltage division module is connected with the negative feedback module, the operation module and the single-chip microcomputer module respectively, the output end of the voltage division module is used to output the target signal, the single-chip microcomputer module accurately controls the intelligent digital potentiometer of the voltage division module, realizes the dynamic control of the voltage division coefficient, and thus outputs the target signal; the target signal is an electric signal in a specific logarithmic relationship with the input signal, and the logarithmic base is determined by the voltage division coefficient.

[0033] It can be understood that the negative feedback module receives the input signal and performs a preliminary proportional operation to generate an inverse proportional signal. The transistor module utilizes the nonlinear characteristics of the transistor to convert the inverse proportional signal of the negative feedback module into a current signal and perform logarithmic processing. Meanwhile, as a feedback element of the negative feedback module, the operation module receives the logarithmic signal output by the transistor module and further processes it. At the same time, the single-chip microcomputer module runs the control program through the microcontroller chip to accurately adjust the resistance value of the intelligent digital potentiometer in the voltage division module, thereby achieving dynamic control of the voltage division coefficient and dynamically controlling the output of the target signal.

[0034] As Figure 2 As shown in the schematic diagram of the exchangeable base logarithmic amplification circuit, the resistance value of the intelligent digital potentiometer can be adjusted through single-chip microcomputer programming and the analog function module of the control system to determine whether the target logarithmic base is achieved. When the target logarithmic base is not achieved, the microcontroller chip of the single-chip microcomputer module is fed back to replace the appropriate resistance value until the target base is achieved, and the final output resistance value is obtained to derive the final exchangeable base logarithmic function.

[0035] In the above exchangeable base logarithmic amplification circuit, the single-chip microcomputer module accurately controls the intelligent digital potentiometer in the voltage division module to dynamically adjust the resistance value of the intelligent digital potentiometer and achieve real-time adjustment of the voltage division coefficient. Combined with the feedback mechanism, the voltage division coefficient is dynamically optimized to flexibly achieve accurate control of the output logarithmic function base. Specifically, the microcontroller chip of the single-chip microcomputer module controls the resistance value of the intelligent digital potentiometer through the program and determines whether the current base reaches the target value according to the feedback signal. If the target value is not reached, the resistance value is iteratively optimized until the target base requirement is met. Finally, the circuit can flexibly adjust the logarithmic base relationship between the output signal and the input signal to adapt to the demand for base change in different application scenarios, thereby significantly improving the practicality and application range of the logarithmic amplifier.

[0036] In one embodiment, the above exchangeable base logarithmic amplification circuit further includes a thermistor in the voltage division module for temperature compensation of the transistor module.

[0037] It can be understood that the transistor module, as the core nonlinear element, will drift with changes in environmental temperature, thereby affecting the overall accuracy of the circuit. By adding a thermistor to the voltage division module, the temperature drift effect of the transistor module is compensated by adjusting the voltage division coefficient. Specifically, the thermistor is connected in series or parallel with the resistance network in the voltage division module, and its resistance value changes with temperature. A positive temperature coefficient (PTC) or negative temperature coefficient (NTC) thermistor can be selected according to design requirements.

[0038] In one embodiment, as Figure 3As shown in the second schematic diagram of the structure of the exchangeable base logarithmic amplification circuit, the embodiment of the present application provides an exchangeable base logarithmic amplification circuit, the negative feedback module includes a first operational amplifier and a resistor; the transistor module includes a pair of matched transistors; the operation module includes a second operational amplifier and a precision reference voltage source; the voltage division module includes an intelligent digital potentiometer and a thermistor; and the single-chip microcomputer module includes a microcontroller chip and a program memory.

[0039] It can be understood that there is a logarithmic relationship between the base-emitter voltage V be and the collector current I o of the transistor, and through static and dynamic analysis of the circuit, the expression of the logarithmic amplification circuit can be obtained as follows:

[0040]

[0041] wherein V IO2 represents the output voltage; KT / Q is equal to 0.02568V (room temperature 25 degrees), wherein K represents the Boltzmann constant, T represents the temperature in Kelvin, and Q represents the charge of an electron; R4 represents the resistance of the intelligent digital potentiometer; R6 represents the thermistor; R1 and R7 represent the resistors; V DC1 represents the voltage source of the collector current of the second transistor in the transistor module, that is, the precision reference voltage source; and V IO1 represents the input voltage, that is, the input signal.

[0042] Firstly, the input signal is input into the negative feedback module through the reverse proportional operational amplifier circuit, and then the characteristics of the transistor are utilized to convert the ratio of I O1 and I O2 into a logarithm, and the logarithmic constant is determined by the voltage division ratio. In order to make the output of 2V obtained by 100 times of change, the output of the first operational amplifier is connected to the intelligent digital potentiometer, and then the resistance R4 is precisely controlled by the single-chip microcomputer module, wherein Key=A below R4 represents the pin connection of the intelligent digital potentiometer. DC1 represents the voltage source of the collector current of the second transistor (that is, Q2) in the transistor module, which is used to fix the collector current of Q2, and R6 is a thermistor, which is a negative temperature thermistor (NTC) used for temperature compensation of the transistor. The resistance value of the thermistor decreases with the increase of temperature.

[0043] Specifically, the single-chip microcomputer module is the core control unit of the exchangeable base logarithmic amplification circuit, which mainly includes a microcontroller (micro control unit) chip and a program memory. The microcontroller chip is responsible for executing circuit control tasks to ensure that the circuit can output target signals according to predetermined requirements. The program memory is used to store the control program executed by the microcontroller chip, which guides the microcontroller chip to adjust system parameters and control the intelligent digital potentiometer to realize dynamic switching between different bases.

[0044] Through the expression of the push, it can be concluded that the single-chip microcomputer module can precisely control the resistance R4 of the intelligent digital potentiometer to realize the base conversion of the output logarithmic function. The relevant implementation base conversion derivation process is as follows:

[0045] Let Through analysis, the following expression can be obtained:

[0046]

[0047] Let The following related expressions can be obtained:

[0048]

[0049] The logarithmic function formula can be converted into the following expression:

[0050]

[0051] In addition, in the present embodiment, the single-chip microcomputer module control intelligent digital potentiometer principle diagram is shown in Figure 4 , including X9C103 intelligent digital potentiometer, STC12C5A60S2 single-chip microcomputer and peripheral circuit, through the serial interface connection of single-chip microcomputer and intelligent digital potentiometer, realizing the digital control of intelligent digital potentiometer resistance value (the total resistance value of intelligent digital potentiometer is Figure 4 A and B end interface value). The peripheral circuit provides necessary power supply, signal transmission and protection function, ensuring that the single-chip microcomputer can accurately adjust the resistance value of the intelligent digital potentiometer to meet the specific requirements.

[0052] The single-chip microcomputer module control flow chart is shown in Figure 5 , the flow starts from system startup, first initializes the single-chip microcomputer and intelligent digital potentiometer. Then, the single-chip microcomputer receives and analyzes the control signal, adjusts the resistance value of the potentiometer according to the analysis result, and checks whether the target value is reached. If the target value is not reached, the resistance value is adjusted and the control signal is received again; if the target value is reached, the final resistance value is output, and the flow is completed. This cycle and judgment mechanism ensures that the intelligent digital potentiometer can accurately match the system requirements, and finally realizes the optimization control of the target circuit parameters.

[0053] Combined with Figure 4 , Figure 5 and the above derivation process, the total resistance value of the intelligent digital potentiometer is Figure 4 A and B end interface value, the single-chip microcomputer module controls the change of the value of R4 of the intelligent digital potentiometer, thereby causing the change of the division coefficient Y, and the logarithmic base e YThe change, that is, the resistance of the smart digital potentiometer R4 is controlled by the microcontroller chip of the single-chip module, so as to realize the control of the logarithmic function base conversion, that is, the variable base logarithmic function.

[0054] In one embodiment, the above-mentioned variable-base logarithmic amplification circuit, the smart digital potentiometer is an X9C103 smart digital potentiometer.

[0055] It can be understood that the X9C103 smart digital potentiometer has obvious advantages over traditional potentiometers in terms of accuracy, non-volatile storage, low power consumption, digital control, durability, compatibility, and wide application. These characteristics make X9C103 become a high-efficiency and stable solution in application scenarios that require accurate resistance adjustment, especially in circuit design that requires high accuracy, reliability and long service life.

[0056] In one embodiment, the above-mentioned variable-base logarithmic amplification circuit, the negative feedback module includes an operational amplifier chip with model number OPA2277U.

[0057] It can be understood that the operational amplifier chip with model number OPA2277U is used in the negative feedback module. This chip has the characteristics of high precision, high stability and low noise, and is suitable for occasions that require high-performance amplifiers. Specifically, the low-noise performance of the OPA2277U operational amplifier chip helps to reduce interference in the signal processing process, ensuring the clarity and accuracy of the output signal; its high stability ensures the reliability of the circuit during long-term operation; and high precision makes the logarithmic amplification circuit can provide more accurate calculation results in different application scenarios. Therefore, using the OPA2277U operational amplifier chip can significantly improve the overall performance of the variable-base logarithmic amplification circuit, ensuring that it performs best in high-precision and high-reliability applications.

[0058] In one embodiment, the above-mentioned variable-base logarithmic amplification circuit, the operational module includes an operational amplifier chip with model number OPA2277U.

[0059] It can be understood that the operational module also uses an operational amplifier chip with model number OPA2277U.

[0060] In one embodiment, the above-mentioned variable-base logarithmic amplification circuit, the transistor module includes a transistor with model number BC184BP.

[0061] It can be understood that the transistor module uses a transistor of model BC184BP. The BC184BP transistor has the advantages of high precision, high stability and low noise in circuit design. Specifically, the high precision performance of the BC184BP transistor can ensure accurate control of current and voltage during signal amplification, reduce signal distortion, and maintain the quality of the signal; its high stability ensures that the circuit can continue to operate stably for a long time, avoiding performance fluctuations due to temperature changes or other environmental factors; and the low noise characteristic helps to reduce noise interference and ensure the clarity and accuracy of the signal output. Therefore, the use of the BC184BP transistor enables the replaceable base logarithmic amplification circuit to provide reliable and clear signal amplification effect under the requirements of high precision and high stability, improving the performance and reliability of the entire circuit.

[0062] Those skilled in the art can understand that each module of the above circuit can include other necessary component structures not mentioned in addition to the proposed elements, and can be understood in the same way as the existing structure of various types of logarithmic amplification circuits in the art.

[0063] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered as the scope of the present application.

[0064] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A replaceable logarithmic amplifier circuit, characterized in that, include: Negative feedback module, transistor module, arithmetic module, voltage divider module, and microcontroller module; The input terminal of the negative feedback module is used to connect to the input signal and perform proportional calculation on the input signal to output the signal; the input terminal of the transistor module is connected to the output terminal of the negative feedback module, and the output terminal of the transistor module is connected to the input terminal of the arithmetic module. The transistor module is the feedback element of the negative feedback module. The input terminals of the voltage divider module are respectively connected to the negative feedback module, the arithmetic module, and the microcontroller module. The output terminal of the voltage divider module is used to output the target signal. The microcontroller module precisely controls the intelligent digital potentiometer of the voltage divider module to realize the dynamic control of the voltage division coefficient, thereby outputting the target signal. The target signal is an electrical signal that has a specific logarithmic relationship with the input signal, and the base of the logarithm is determined by the voltage division coefficient.

2. The logarithmic amplifier circuit with a replaceable base according to claim 1, characterized in that, The voltage divider module also includes a thermistor for temperature compensation of the transistor module.

3. The logarithmic amplifier circuit with a replaceable base according to claim 2, characterized in that, The negative feedback module includes a first operational amplifier and a resistor; the transistor module includes a pair of matched transistors; the operational module includes a second operational amplifier and a precision reference voltage source; the voltage divider module includes the intelligent digital potentiometer and the thermistor; and the microcontroller module includes a microcontroller chip and a program memory.

4. The logarithmic amplifier circuit with a replaceable base according to any one of claims 1 to 3, characterized in that, The intelligent digital potentiometer is the X9C103 intelligent digital potentiometer.

5. The logarithmic amplifier circuit with a replaceable base according to claim 4, characterized in that, The negative feedback module includes an operational amplifier chip of model OPA2277U.

6. The logarithmic amplifier circuit with a replaceable base according to claim 4, characterized in that, The computing module includes an operational amplifier chip with the model number OPA2277U.

7. The logarithmic amplifier circuit with a replaceable base according to claim 4, characterized in that, The transistor module includes transistors of model BC184BP.

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