CN117650767A - Impedance transformation circuit, oscilloscope front-end circuit and oscilloscope - Google Patents
Impedance transformation circuit, oscilloscope front-end circuit and oscilloscope Download PDFInfo
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H11/00—Networks using active elements
- H03H11/02—Multiple-port networks
- H03H11/28—Impedance matching networks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R13/00—Arrangements for displaying electric variables or waveforms
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/561—Voltage to current converters
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H11/00—Networks using active elements
- H03H11/02—Multiple-port networks
- H03H11/24—Frequency-independent attenuators
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Abstract
An impedance transformation circuit, an oscilloscope front-end circuit and an oscilloscope relate to the technical field of electrical and electronic measurement. The circuit comprises an alternating current coupling module, a voltage-current conversion module, a serial current-voltage conversion module, a parallel current-voltage conversion module, an amplifying module and an integrator module. The voltage-current conversion module acquires a high-frequency voltage signal and a voltage adjustment signal to generate a first current signal; the series current-voltage conversion module is connected with the voltage-current conversion module to transmit a first current signal and convert the first current signal into a first voltage signal; the parallel current-voltage conversion module is connected to the series current-voltage conversion module to generate an output voltage signal and a reference voltage. The integrator module is connected with the amplifying module, the series current-voltage conversion module and the parallel current-voltage conversion module to generate a voltage adjustment signal and input the voltage adjustment signal to the voltage-current conversion module, so that an impedance conversion circuit, an oscilloscope front-end circuit and an oscilloscope with equal high-frequency and low-frequency output impedance are provided.
Description
Technical Field
The invention relates to the technical fields of electrician, electronics and measurement, in particular to an impedance transformation circuit, an oscilloscope front-end circuit and an oscilloscope.
Background
Digital oscilloscopes are common general test measurement devices, and in the prior art, digital oscilloscopes generally comprise an input analog front-end circuit, an analog-to-digital conversion circuit, a digital processing circuit, a display circuit and the like. The input analog front-end circuit of the oscilloscope is used for conditioning input signals and comprises the functions of input impedance matching, signal attenuation, AC coupling, DC coupling, signal amplification, direct current bias and the like, so that the input analog front-end circuit often determines key performance indexes of the oscilloscope.
The prior oscilloscope analog front-end circuit is shown in fig. 1, and comprises an input impedance selection circuit, an attenuation circuit, an impedance transformation circuit, an AD/DC coupling selection circuit, a bias adjustment circuit and a variable gain amplification circuit. The impedance transformation circuit adopts a high-frequency low-frequency path separation circuit, and the circuit needs to adjust the low-frequency path gain to be consistent with the high-frequency path gain, so that the amplitude-frequency response is flat, and the problem of low-frequency square wave distortion caused by uneven amplitude-frequency response is avoided. The low frequency path of the circuit adopts voltage type deep negative feedback, so that the output impedance approaches 0 at low frequency, and the high frequency path does not adopt deep negative feedback, so that the output impedance does not approach 0 at high frequency. For example, the high frequency output impedance in the oscilloscope analog front end circuit diagram in fig. 1 is the output impedance of the transistor Q4, and the output impedance of the circuit at low frequency is inconsistent with the output impedance at high frequency, so that when the load driven by the circuit changes, the change amount of the low frequency gain is inconsistent with the change amount of the high frequency gain, and the amplitude-frequency response is uneven.
Disclosure of Invention
The invention mainly solves the technical problems that: an impedance conversion circuit is provided in which the output impedance at low frequency is the same as the output impedance at high frequency.
According to a first aspect, there is provided in one embodiment an impedance transformation circuit comprising:
the alternating current coupling module is used for acquiring an input signal and extracting a high-frequency voltage signal of the input signal;
the first input end of the voltage-current conversion module is connected with the output end of the alternating current coupling module; the second input end of the voltage-current conversion module is used for acquiring a voltage adjustment signal; the voltage-current conversion module correspondingly converts the high-frequency voltage signal and the voltage adjustment signal into current signals and sums the current signals to generate a first current signal;
the series current-voltage conversion module is connected to the voltage-current conversion module; the first output end of the series current-voltage conversion module is used for outputting the first current signal, and the second output end of the series current-voltage conversion module is used for converting the first current signal into a first voltage signal;
the parallel current-voltage conversion module is connected to the first output end of the series current-voltage conversion module; the first output end of the parallel current-voltage conversion module is used for converting the first current signal into a second voltage signal so as to generate an output voltage signal; the second output end of the parallel current-voltage conversion module is used for outputting reference voltage;
the amplifying module is used for acquiring an input signal and a direct current offset signal, amplifying and summing the input signal and the direct current offset signal to generate an amplified signal;
the first input end of the integrator module is connected with the amplifying module; the second input end of the integrator module is connected with the second output end of the series current-voltage conversion module; the third input end of the integrator module is connected with the second output end of the parallel current-voltage conversion module; the integrator module obtains the reference voltage to comparatively integrate the amplified signal, the first voltage signal, and the reference voltage to generate the voltage adjustment signal.
In one embodiment, the voltage-to-current conversion module includes a resistor R6, a transistor Q2, a resistor R7, and a filter capacitor C3;
the first end of the resistor R6 is connected with the output end of the alternating current coupling module, and the second end of the resistor R6 is used for obtaining working voltage; the control end of the transistor Q2 is connected with the first end of the resistor R6, the first end of the transistor Q2 is connected with the first end of the resistor R7, the second end of the transistor Q2 is connected with the series current voltage conversion module, the second end of the resistor R7 is connected with the first end of the filter capacitor C3, the second end of the filter capacitor C3 is grounded, and the second end of the resistor R7 is also used for acquiring the voltage adjustment signal.
In one embodiment, the series current-to-voltage conversion module includes a sampling resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, and an amplifier U3;
the first end of the current collecting resistor R8 is connected with the voltage-current conversion module, and the second end of the current collecting resistor R8 is used as a first output end of the series current-voltage conversion module; the second end of the current collection resistor R8 is also connected with the first end of a resistor R9, the first end of the current collection resistor R8 is also connected with the first end of a resistor R10, the second end of the resistor R9 is connected with the inverting input end of the amplifier U3, the second end of the resistor R10 is connected with the non-inverting input end of the amplifier U3, the second end of the resistor R9 is also connected with the first end of a resistor R12, the second end of the resistor R12 is connected with the output end of the amplifier U3, the second end of the resistor R10 is also connected with the first end of a resistor R11, and the second end of the resistor R11 is grounded; the output end of the amplifier U3 is also connected with the first end of a resistor R13, and the second end of the resistor R13 is used as the second output end of the series current-voltage conversion module.
In one embodiment, the parallel current-to-voltage conversion module includes a resistor R14 and a resistor R15;
the first end of the resistor R14 is connected with the first output end of the series current-voltage conversion module, and the first end of the resistor R14 is also used as the first output end of the parallel current-voltage conversion module; the second end of the resistor R14 is connected with the first end of the resistor R15, the first end of the resistor R15 is also connected with a reference voltage, and the second end of the resistor R15 is used as the second output end of the parallel current-voltage conversion module.
In one embodiment, the amplifying module includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, and an amplifier U1;
the first end of the resistor R1 is used for acquiring an input signal, the second end of the resistor R1 is connected with the first end of the resistor R2, the second end of the resistor R2 is grounded, the first end of the resistor R2 is also connected with the non-inverting input end of the amplifier U1, the first end of the resistor R4 is used for acquiring a direct current bias signal, the second end of the resistor R4 is connected with the inverting input end of the amplifier U1, the output end of the amplifier U1 is connected with the first end of the resistor R5, and the second end of the resistor R5 is used for outputting the amplified signal; the first end of the resistor R3 is connected with the second end of the resistor R4, and the second end of the resistor R3 is connected with the first end of the resistor R5.
In one embodiment, the integrator module includes an amplifier U2, a capacitor C2, and a transistor Q3;
the non-inverting input end of the amplifier U2 is grounded, the inverting input end of the amplifier U2 is connected with the amplifying module, the inverting input end of the amplifier U2 is also connected with the second output end of the series current voltage conversion module, the inverting input end of the amplifier U2 is also connected with the second output end of the parallel current voltage conversion module, the output end of the amplifier U2 is connected with the control end of the transistor Q3, the first end of the transistor Q3 is connected with the working voltage, and the second end of the transistor Q3 is used for outputting the voltage regulating signal; the first end of the capacitor C2 is connected with the output end of the amplifier U3, and the second end of the capacitor C2 is connected with the inverting input end of the amplifier U3.
In one embodiment, the ac coupling module includes a capacitor C1, a first end of the capacitor C1 is used to obtain the input signal, and a second end of the capacitor C1 is used to output the high-frequency voltage signal.
In one embodiment, the impedance transformation circuit determines a low frequency gain of the impedance transformation circuit from the series current-to-voltage conversion module, the parallel current-to-voltage conversion module, the amplification module, and the integrator module; the impedance transformation circuit determines the high-frequency gain of the impedance transformation circuit according to the voltage-current transformation module and the parallel current-voltage transformation module.
According to a second aspect, in one embodiment there is provided an oscilloscope front end circuit comprising:
the direct current bias circuit is used for outputting a direct current bias signal;
an impedance transformation circuit, wherein the impedance transformation circuit is any one of the impedance transformation circuits according to the embodiments;
and the variable gain amplifier is used for carrying out voltage amplification or voltage attenuation on the signal output by the impedance change circuit.
According to a third aspect, an embodiment provides an oscilloscope, comprising:
the data acquisition module comprises the oscilloscope front-end circuit described in the embodiment and is used for acquiring signal data of each channel;
the data processing module is connected with the data acquisition module and is used for processing the acquired signal data;
and the waveform generation module is connected with the data processing module and is used for generating waveform image data according to the processed signal data.
According to the embodiment, the impedance transformation circuit, the front-end circuit of the oscilloscope and the oscilloscope. The impedance transformation circuit comprises an alternating current coupling module, a voltage-current conversion module, a series current-voltage conversion module, a parallel current-voltage conversion module, an amplifying module and an integrator module. The voltage-current conversion module acquires a high-frequency voltage signal and a voltage adjustment signal to generate a first current signal; the series current-voltage conversion module is connected with the voltage-current conversion module to transmit a first current signal and convert the first current signal into a first voltage signal; the parallel current-voltage conversion module is connected to the series current-voltage conversion module to generate an output voltage signal and a reference voltage. The integrator module is connected with the amplifying module, the series current-voltage conversion module and the parallel current-voltage conversion module to generate a voltage adjustment signal and input the voltage adjustment signal to the voltage-current conversion module. The integrator module is connected with the series voltage conversion module so that the series voltage conversion module is in current type negative feedback, under the negative feedback, the output impedance of the impedance change circuit in the low frequency band is only determined by the parallel current voltage conversion module, meanwhile, as the integrator module needs to obtain a better integration result, the integrator module works in the low frequency band and does not work in the high frequency band, and therefore, the output impedance of the high frequency band is also determined by the parallel current voltage conversion module only, and the output impedance of the integrator module in the low frequency band is the same as the output impedance of the integrator module in the high frequency band.
Drawings
FIG. 1 is a schematic diagram of an analog front-end circuit of an oscilloscope according to the prior art;
FIG. 2 is a schematic diagram of an impedance transformation circuit according to an embodiment;
FIG. 3 is a schematic diagram of an impedance transformation circuit according to an embodiment;
fig. 4 is a circuit schematic of an oscilloscope analog front end circuit according to another embodiment.
Detailed Description
The invention will be described in further detail below with reference to the drawings by means of specific embodiments. Wherein like elements in different embodiments are numbered alike in association. In the following embodiments, numerous specific details are set forth in order to provide a better understanding of the present application. However, one skilled in the art will readily recognize that some of the features may be omitted, or replaced by other elements, materials, or methods in different situations. In some instances, some operations associated with the present application have not been shown or described in the specification to avoid obscuring the core portions of the present application, and may not be necessary for a person skilled in the art to describe in detail the relevant operations based on the description herein and the general knowledge of one skilled in the art.
Furthermore, the described features, operations, or characteristics of the description may be combined in any suitable manner in various embodiments. Also, various steps or acts in the method descriptions may be interchanged or modified in a manner apparent to those of ordinary skill in the art. Thus, the various orders in the description and drawings are for clarity of description of only certain embodiments, and are not meant to be required orders unless otherwise indicated.
The numbering of the components itself, e.g. "first", "second", etc., is used herein merely to distinguish between the described objects and does not have any sequential or technical meaning. The terms "coupled" and "connected," as used herein, are intended to encompass both direct and indirect coupling (coupling), unless otherwise indicated.
In order to solve the problem that the output impedance of the impedance transformation circuit in the prior art is inconsistent with the output impedance of the impedance transformation circuit in the high frequency, the application provides an impedance transformation circuit, and the following description is made.
Referring to fig. 2, in one embodiment, the impedance transformation circuit 100 of the present application includes an ac coupling module 110, a voltage-to-current conversion module 120, a series current-to-voltage conversion module 130, a parallel current-to-voltage conversion module 140, an amplifying module 150, and an integrator module 160, and is developed one by one.
Referring to fig. 3, in one embodiment, the ac coupling module 110 includes a capacitor C1, and a first end of the capacitor C1 is used to obtain an input signal and block dc and low frequency signals in the input signal from entering the voltage-to-current conversion module, that is, extract a high frequency voltage signal in the input signal.
In one embodiment, the voltage-to-current conversion module 120 includes two input terminals and one output terminal, wherein a first input terminal of the voltage-to-current conversion module 120 is connected to the output terminal of the ac coupling module 110, i.e., a second terminal of the capacitor C1, and a second input terminal of the voltage-to-current conversion module 120 is used for obtaining the voltage adjustment signal. The voltage-current conversion module converts the high-frequency voltage signal and the voltage adjustment signal into current signals, respectively, and then sums the converted current signals to generate a first current signal, and outputs the first current signal from the output end of the voltage-current conversion module 120.
Referring to fig. 3, in one embodiment, the voltage-to-current conversion module 120 includes a resistor R6, a transistor Q2, a resistor R7, and a filter capacitor C3. The first end of the resistor R6 is connected to the second end of the capacitor C1, and the second end of the resistor R6 is used for obtaining the operating voltage (i.e. VEE1 in fig. 3, VEE1 provides the static operating voltage to the transistor Q2 through the resistor R6). The control terminal of the transistor Q2 is connected to the first terminal of the resistor R6, the first terminal of the transistor Q2 is connected to the first terminal of the resistor R7, and the second terminal of the transistor Q2 is used as the output terminal of the voltage-to-current conversion module 120 and connected to the series current-to-voltage conversion module 130. The second end of the resistor R7 is connected to the first end of the filter capacitor C3, the second end of the filter capacitor C3 is grounded, and the second end of the resistor R7 is further configured to obtain a voltage adjustment signal, where the resistor R7 is configured to provide a conversion gain of the voltage-to-current conversion module 120. The relationship between the sum of the high frequency voltage signal and the voltage adjustment signal and the first current signal in the voltage-to-current conversion module 120 is: i=v/R R7 . Wherein I is the current corresponding to the first current signal, V is the sum of voltages corresponding to the high-frequency voltage signal and the voltage adjustment signal, R R7 Is the resistance of the resistor R7.
In one embodiment, the series current to voltage conversion module 130 includes one input terminal and two output terminals, and the input terminal of the series current to voltage conversion module 130 is connected to the output terminal of the voltage to current conversion module. The first output end of the series current-voltage conversion module 130 directly outputs the first current signal output by the voltage-current conversion module, and the second output end of the series current-voltage conversion module 130 converts the first current signal into a first voltage signal and outputs the first voltage signal.
Referring to fig. 3, in one embodiment, the series current-to-voltage conversion module 130 includes a sampling resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, and an amplifier U3. The first end of the current collecting resistor R8 is used as the input end of the series current-voltage conversion module 130, is connected with the voltage-current conversion module 120, and the second end of the current collecting resistor R8 is used as the first output end of the series current-voltage conversion module 130, so that a first current signal is directly output. The second end of the current collecting resistor R8 is further connected with the first end of a resistor R9, the first end of the current collecting resistor R8 is further connected with the first end of a resistor R10, the second end of the resistor R9 is connected with the inverting input end of the amplifier U3, the second end of the resistor R10 is connected with the non-inverting input end of the amplifier U3, the second end of the resistor R9 is further connected with the first end of a resistor R12, the second end of the resistor R12 is connected with the output end of the amplifier U3, the second end of the resistor R10 is further connected with the first end of a resistor R11, the second end of the resistor R11 is grounded, the output end of the amplifier U3 is further connected with the first end of a resistor R13, and the second end of the resistor R13 serves as the second output end of the series current voltage conversion module to output a first voltage signal.
In the series current-voltage conversion module 130, the current sampling resistor R8 is used for converting the first current signal into the first voltage signal, and the operational amplifier U3 and the peripheral resistor are used for extracting the first voltage signal converted by the current sampling resistor R8, amplifying the first voltage signal, and outputting the amplified first voltage signal to the integrator module 160 through the resistor R13. In one embodiment, the resistance of the resistor R9 is equal to the resistance of the resistor R10, and the resistance of the resistor R12 is equal to the resistance of the resistor R11.
In one embodiment, the parallel current-to-voltage conversion module 140 includes one input terminal and two output terminals, and the input terminal of the parallel current-to-voltage conversion module 140 is connected to the first output terminal of the series current-to-voltage conversion module, for obtaining the first current signal and converting the first current signal into the second voltage signal, so as to generate the output voltage signal, and output the output voltage signal from the first output terminal of the parallel current-to-voltage conversion module 140. The second output terminal of the parallel current-voltage conversion module 140 is used for outputting a reference voltage.
Referring to fig. 3, in one embodiment, the parallel current-to-voltage conversion module 140 includes a resistor R14 and a resistor R15. The first end of the resistor R14 is connected to the first output end of the series current-voltage conversion module 130, and the first end of the resistor R14 is also used as the first output end of the parallel current-voltage conversion module 140 to output an output voltage signal. The second terminal of the resistor R14 is connected to the first terminal of the resistor R15, the first terminal of the resistor R15 is further connected to a reference voltage (i.e., VCC in fig. 3), and the second terminal of the resistor R15 is used as the second output terminal of the parallel current-voltage conversion module 140 to output the reference voltage (i.e., VCC in fig. 3).
The resistor R14 converts the first current signal into the second voltage signal, and determines the output impedance of the output voltage signal. The reference voltage VCC is connected to the integrator module 160 through a resistor R15 for the purpose of providing a quiescent operating current for the voltage to current conversion module 120. The static operating current is calculated using the following formula:
；
wherein VCC represents a reference voltage, R R13 Represents the resistance value of the resistor R13, R R9 Represents the resistance value of the resistor R9, R R15 Represents the resistance value of the resistor R15, R R8 Represents the resistance value of the resistor R8, R R12 The resistance of the resistor R12 is shown.
In one embodiment, the amplifying module 150 includes two input terminals and one output terminal, the first input terminal of the amplifying module 150 is used for obtaining an input signal, the second input terminal of the amplifying module 150 is used for obtaining a dc offset signal, and the amplifying module 150 amplifies and sums the input signal and the dc offset signal, thereby generating an amplified signal, and outputs the amplified signal through the output terminal of the amplifying module 150. In one embodiment, the amplification module 150 employs a low frequency amplifier.
Referring to fig. 3, in one embodiment, the amplifying module 150 includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, and an amplifier U1. The first end of the resistor R1 is used as a first input end of the amplifying module 150 for obtaining an input signal, the second end of the resistor R1 is connected to the first end of the resistor R2, and the second end of the resistor R2 is grounded. The first end of the resistor R2 is further connected to the non-inverting input end of the amplifier U1, the first end of the resistor R4 is used as the second input end of the amplifying module 150, and is used for obtaining a dc bias signal, the second end of the resistor R4 is connected to the inverting input end of the amplifier U1, the output end of the amplifier U1 is connected to the first end of the resistor R5, and the second end of the resistor R5 is used as the output end of the amplifying module 150, and is used for outputting an amplified signal. The first end of the resistor R3 is connected with the second end of the resistor R4, and the second end of the resistor R3 is connected with the first end of the resistor R5.
In one embodiment, the integrator module 160 includes three inputs and one output, and a first input of the integrator module 160 is connected to the output of the amplifying module 150 to obtain an amplified signal; a second input terminal of the integrator module 160 is connected to a second output terminal of the series current-voltage conversion module 130 to obtain a first voltage signal; a third input terminal of the integrator module 160 is connected to a third output terminal of the parallel current-to-voltage conversion module 140 to obtain a reference voltage, which is a quiescent operating current provided to the voltage-to-current conversion module 120. The integrator module 160 compares and integrates the obtained amplified signal, the first voltage signal, and the reference voltage to generate a voltage adjustment signal, and inputs the voltage adjustment signal to the second input terminal of the voltage-to-current conversion module 120.
Referring to fig. 3, the integrator module 160 includes an amplifier U2, a capacitor C2 and a transistor Q3. The non-inverting input end of the amplifier U2 is grounded, and the inverting input end of the amplifier U2 is used as a first input end of the integrator module 160 and is connected with the amplifying module 150; the inverting input of the amplifier U2 is also used as a second input of the integrator module 160, and is connected to the second output of the series current-voltage conversion module 130; the inverting input of amplifier U2 also serves as a third input of integrator block 160, connected to a second output of parallel current-to-voltage conversion block 140. The output end of the amplifier U2 is connected to the control end of the transistor Q3, the first end of the transistor Q3 is connected to the operating voltage, and the second end of the transistor Q3 serves as the output end of the integrator module 160, and outputs a voltage adjustment signal. The first end of the capacitor C2 is connected with the output end of the amplifier U3, and the second end of the capacitor C2 is connected with the inverting input end of the amplifier U3.
In one embodiment, the amplifier U2 in the integrator module 160 operates in the low frequency mode, and the non-inverting input terminal of the amplifier U2 is grounded, and the inverting input terminal of the amplifier U2 is connected to the amplifying module 150, the series current-voltage converting module 130, and the parallel current-voltage converting module 140, where the voltage of the output voltage signal output by the parallel current-voltage converting module 140 is the voltage of the resistor R14 multiplied by the current flowing through the sampling resistor R8, so that it is known that the current of the sampling resistor R8 is the voltage of the output voltage signal divided by the resistance value of the resistor R14, and the series current-voltage converting module 130 amplifies the current flowing through the sampling resistor R8 and then inputs the amplified current to the inverting input terminal of the amplifier U2, so that the first voltage signal input to the inverting input terminal of the amplifier U2 by the series current-voltage converting module 130 includes the output voltage signal. Meanwhile, the inverting input terminal of the amplifier U2 also obtains an input signal through the amplifying module 150. The voltages at the non-inverting input and the inverting input of the amplifier U2 are forced to be equal in the integrator module 160, but in the present application, the non-inverting input of the amplifier U2 is grounded, so that only the inverting input of the amplifier U2 needs to be zero, that is, the relationship between the input signal passing through the amplifying module 150 and the output voltage signal passing through the series current-voltage converting module 130 and the parallel current-voltage converting module 140 is established at the inverting input of the amplifier U2, and the sum is zero, and if the sum is not zero, the non-inverting input and the inverting input of the amplifier U2 are adjusted according to the voltage adjustment signal output by the output of the amplifier U2. As a result, the low frequency gain of the impedance transformation circuit 100 is determined by the loads of the series current-voltage conversion module 130, the parallel current-voltage conversion module 140, the amplification module 150, the integrator module 160, and the output voltage signal, and the relationship between the input signal and the output voltage signal is rectified to obtain the low frequency gain of the impedance transformation circuit 100, which is expressed as follows:
；
wherein GL represents the low frequency gain, R, of the impedance transformation circuit 100 R2 Represents the resistance value of the resistor R2, R R3 Represents the resistance value of the resistor R3, R R4 Represents the resistance value of the resistor R4, R R13 Represents the resistance value of the resistor R13, R R14 The resistance of the resistor R14, the resistance of the load of the output voltage signal represented by RL, R R9 Represents the resistance value of the resistor R9, R R1 Represents the resistance value of the resistor R1, R R5 Represents the resistance value of the resistor R5, R R8 Represents the resistance value of the resistor R8, R R12 The resistance of the resistor R12 is shown.
It should be noted that, in the low frequency band, the series current-voltage conversion module 130 is used to provide the current-type deep negative feedback, so that the output impedance of the impedance conversion circuit 100 in the low frequency band is only determined by the parallel current-voltage conversion module 140. That is, since the non-inverting input terminal and the inverting input terminal of the amplifier U2 are equal at the time of the amplifier U2, the current flowing through the sampling resistor R8 in the series current-voltage conversion module 130 is always constant. Then, the series current-voltage conversion module 130 and the integrator module 160, which take part in the current resistor R8, correspond to one constant current source with an impedance of infinity, as seen from the output voltage signal toward the series current-voltage conversion module 130. Therefore, in the low frequency band, the output impedance corresponding to the output voltage signal is an infinite resistor connected in parallel to the resistor R14 in the parallel current-voltage conversion module 140, and finally the output impedance of the low frequency band is the resistance value of the resistor R14. In one embodiment, the resistance of resistor R14 is designed to be 50Ω.
In one embodiment, when the impedance transformation circuit 100 is operated in the high frequency mode, the amplifier U2 in the integrator module 160 is not operated, and the high frequency gain is determined only by the voltage-to-current conversion module 120, the parallel current-to-voltage conversion module 140, and the load of the output voltage signal, which is specifically determined by the resistor R7, the resistor R14, and the load of the output voltage signal together:
；
where GH denotes the low frequency gain, R, of the impedance transformation circuit 100 R14 The resistance of the resistor R14, the resistance of the load of the output voltage signal represented by RL, R R7 The resistance of the resistor R7 is shown.
It should be noted that, in the high frequency band, since the integrator module 160 fails to operate, the impedance seen from the output voltage signal toward the series current-voltage conversion module 130 is the impedance seen by the collector of the transistor Q2 added to the current-collecting resistor R8, and since the transistor Q2 operates in the linear region, the impedance seen from the collector of the transistor Q2 is much larger than 50Ω. At this time, the output impedance corresponding to the output voltage signal is that the resistor R14 in the parallel current-voltage conversion module 140 is connected in parallel with a resistor (i.e. equivalent to an infinite resistor) that is far greater than 50Ω, so that the output impedance of the high frequency band is the resistance value of the resistor R14. In one embodiment, the resistance of resistor R14 is designed to be 50Ω. When designing parameters of each hardware in the impedance conversion circuit 100, gl=gh is set.
Accordingly, the impedance conversion circuit 100 provided in the present application has the impedance of the signal output at the low frequency band consistent with the impedance of the signal output at the high frequency band, and when the load driven by the circuit changes, the amount of change of the low frequency gain is consistent with the amount of change of the high frequency gain, so that the flatness of the frequency response no longer changes with the change of the load driven by the circuit.
In an embodiment, referring to fig. 4, the oscilloscope front end circuit further includes a dc bias circuit 200, an impedance transformation circuit 100 and a variable gain amplifier 300, where the dc bias circuit 200 is used for outputting a dc bias signal, and the impedance transformation circuit 100 adopts the impedance transformation circuit 100 in any of the above embodiments, which is not described herein again. The variable gain amplifier 300 acquires a signal output from the impedance transformation circuit 100, and performs voltage amplification or voltage attenuation on the signal.
In an embodiment, the application further provides an oscilloscope, where the oscilloscope includes a data acquisition module, a data processing module and a waveform generation module, and the data acquisition module adopts the front-end circuit of the oscilloscope in the above embodiment, so that signal data of each acquisition channel of the oscilloscope is acquired, and since the front-end circuit of the oscilloscope has already been described in the above embodiment, the description is omitted here. The data processing module is connected with the data acquisition module and is used for processing the acquired signal data. The waveform generation module is connected with the data processing module and is used for generating waveform image data according to the processed signal data.
The foregoing description of the invention has been presented for purposes of illustration and description, and is not intended to be limiting. Several simple deductions, modifications or substitutions may also be made by a person skilled in the art to which the invention pertains, based on the idea of the invention.
Claims (10)
1. An impedance transformation circuit, comprising:
the alternating current coupling module is used for acquiring an input signal and extracting a high-frequency voltage signal of the input signal;
the first input end of the voltage-current conversion module is connected with the output end of the alternating current coupling module; the second input end of the voltage-current conversion module is used for acquiring a voltage adjustment signal; the voltage-current conversion module correspondingly converts the high-frequency voltage signal and the voltage adjustment signal into current signals and sums the current signals to generate a first current signal;
the series current-voltage conversion module is connected to the voltage-current conversion module; the first output end of the series current-voltage conversion module is used for outputting the first current signal, and the second output end of the series current-voltage conversion module is used for converting the first current signal into a first voltage signal;
the parallel current-voltage conversion module is connected to the first output end of the series current-voltage conversion module; the first output end of the parallel current-voltage conversion module is used for converting the first current signal into a second voltage signal so as to generate an output voltage signal; the second output end of the parallel current-voltage conversion module is used for outputting reference voltage;
the amplifying module is used for acquiring an input signal and a direct current offset signal, amplifying and summing the input signal and the direct current offset signal to generate an amplified signal;
the first input end of the integrator module is connected with the amplifying module; the second input end of the integrator module is connected with the second output end of the series current-voltage conversion module; the third input end of the integrator module is connected with the second output end of the parallel current-voltage conversion module; the integrator module obtains the reference voltage to comparatively integrate the amplified signal, the first voltage signal, and the reference voltage to generate the voltage adjustment signal.
2. The impedance transformation circuit according to claim 1, wherein the voltage-to-current conversion module comprises a resistor R6, a transistor Q2, a resistor R7, and a filter capacitor C3;
the first end of the resistor R6 is connected with the output end of the alternating current coupling module, and the second end of the resistor R6 is used for obtaining working voltage; the control end of the transistor Q2 is connected with the first end of the resistor R6, the first end of the transistor Q2 is connected with the first end of the resistor R7, the second end of the transistor Q2 is connected with the series current voltage conversion module, the second end of the resistor R7 is connected with the first end of the filter capacitor C3, the second end of the filter capacitor C3 is grounded, and the second end of the resistor R7 is also used for acquiring the voltage adjustment signal.
3. The impedance transformation circuit according to claim 2, wherein the series current-to-voltage conversion module comprises a sampling resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, and an amplifier U3;
the first end of the current collecting resistor R8 is connected with the voltage-current conversion module, and the second end of the current collecting resistor R8 is used as a first output end of the series current-voltage conversion module; the second end of the current collection resistor R8 is also connected with the first end of a resistor R9, the first end of the current collection resistor R8 is also connected with the first end of a resistor R10, the second end of the resistor R9 is connected with the inverting input end of the amplifier U3, the second end of the resistor R10 is connected with the non-inverting input end of the amplifier U3, the second end of the resistor R9 is also connected with the first end of a resistor R12, the second end of the resistor R12 is connected with the output end of the amplifier U3, the second end of the resistor R10 is also connected with the first end of a resistor R11, and the second end of the resistor R11 is grounded; the output end of the amplifier U3 is also connected with the first end of a resistor R13, and the second end of the resistor R13 is used as the second output end of the series current-voltage conversion module.
4. The impedance transformation circuit according to claim 3, wherein the parallel current-to-voltage conversion module includes a resistor R14 and a resistor R15;
the first end of the resistor R14 is connected with the first output end of the series current-voltage conversion module, and the first end of the resistor R14 is also used as the first output end of the parallel current-voltage conversion module; the second end of the resistor R14 is connected with the first end of the resistor R15, the first end of the resistor R15 is also connected with a reference voltage, and the second end of the resistor R15 is used as the second output end of the parallel current-voltage conversion module.
5. The impedance transformation circuit according to claim 4, wherein the amplifying module comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, and an amplifier U1;
the first end of the resistor R1 is used for acquiring an input signal, the second end of the resistor R1 is connected with the first end of the resistor R2, the second end of the resistor R2 is grounded, the first end of the resistor R2 is also connected with the non-inverting input end of the amplifier U1, the first end of the resistor R4 is used for acquiring a direct current bias signal, the second end of the resistor R4 is connected with the inverting input end of the amplifier U1, the output end of the amplifier U1 is connected with the first end of the resistor R5, and the second end of the resistor R5 is used for outputting the amplified signal; the first end of the resistor R3 is connected with the second end of the resistor R4, and the second end of the resistor R3 is connected with the first end of the resistor R5.
6. The impedance transformation circuit according to claim 5, wherein the integrator module comprises an amplifier U2, a capacitor C2, and a transistor Q3;
the non-inverting input end of the amplifier U2 is grounded, the inverting input end of the amplifier U2 is connected with the amplifying module, the inverting input end of the amplifier U2 is also connected with the second output end of the series current voltage conversion module, the inverting input end of the amplifier U2 is also connected with the second output end of the parallel current voltage conversion module, the output end of the amplifier U2 is connected with the control end of the transistor Q3, the first end of the transistor Q3 is connected with the working voltage, and the second end of the transistor Q3 is used for outputting the voltage regulating signal; the first end of the capacitor C2 is connected with the output end of the amplifier U3, and the second end of the capacitor C2 is connected with the inverting input end of the amplifier U3.
7. The impedance transformation circuit according to claim 1, wherein the ac coupling module comprises a capacitor C1, a first end of the capacitor C1 being used for obtaining the input signal, and a second end of the capacitor C1 being used for outputting the high frequency voltage signal.
8. The impedance transformation circuit according to claim 1, wherein the impedance transformation circuit determines a low frequency gain of the impedance transformation circuit from the series current-to-voltage conversion module, the parallel current-to-voltage conversion module, the amplification module, and the integrator module; the impedance transformation circuit determines the high-frequency gain of the impedance transformation circuit according to the voltage-current transformation module and the parallel current-voltage transformation module.
9. An oscilloscope front-end circuit, comprising:
the direct current bias circuit is used for outputting a direct current bias signal;
an impedance transformation circuit employing the impedance transformation circuit according to any one of claims 1 to 8;
and the variable gain amplifier is used for carrying out voltage amplification or voltage attenuation on the signal output by the impedance transformation circuit.
10. An oscilloscope, comprising:
the data acquisition module comprises the oscilloscope front-end circuit according to claim 9, and is used for acquiring signal data of each channel;
the data processing module is connected with the data acquisition module and is used for processing the acquired signal data;
and the waveform generation module is connected with the data processing module and is used for generating waveform image data according to the processed signal data.
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| CN202410115551.6A CN117650767B (en) | 2024-01-29 | 2024-01-29 | Impedance transformation circuit, oscilloscope front-end circuit and oscilloscope |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007006302A (en) * | 2005-06-27 | 2007-01-11 | Sony Corp | Impedance conversion circuit, and high pass filter circuit and frequency conversion circuit employing the same |
| CN110346630A (en) * | 2018-04-03 | 2019-10-18 | 日置电机株式会社 | Current detection means and current-flow test set |
| CN212255421U (en) * | 2020-05-13 | 2020-12-29 | 深圳市鼎阳科技股份有限公司 | Probe circuit of oscilloscope |
| WO2023140566A1 (en) * | 2022-01-18 | 2023-07-27 | 가천대학교 산학협력단 | Serial-connection differential power conditioning system for photovoltaic module equipped with work condition circuit and bypass circuit |
| CN117394805A (en) * | 2022-07-05 | 2024-01-12 | 网络通信与安全紫金山实验室 | Multi-stage monolithic microwave integrated circuit power amplifier |
-
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- 2024-01-29 CN CN202410115551.6A patent/CN117650767B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007006302A (en) * | 2005-06-27 | 2007-01-11 | Sony Corp | Impedance conversion circuit, and high pass filter circuit and frequency conversion circuit employing the same |
| CN110346630A (en) * | 2018-04-03 | 2019-10-18 | 日置电机株式会社 | Current detection means and current-flow test set |
| CN212255421U (en) * | 2020-05-13 | 2020-12-29 | 深圳市鼎阳科技股份有限公司 | Probe circuit of oscilloscope |
| WO2023140566A1 (en) * | 2022-01-18 | 2023-07-27 | 가천대학교 산학협력단 | Serial-connection differential power conditioning system for photovoltaic module equipped with work condition circuit and bypass circuit |
| CN117394805A (en) * | 2022-07-05 | 2024-01-12 | 网络通信与安全紫金山实验室 | Multi-stage monolithic microwave integrated circuit power amplifier |
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