Voltage sampling and amplification circuit and measurement method

Abstract

This invention relates to the field of semiconductor testing technology and provides a voltage sampling amplification circuit and measurement method. The circuit includes a measurement signal selection unit, a signal amplification unit, and a signal following unit. The measurement signal selection unit selects one of a first input signal and a second output signal from the circuit under test (DUT) as the first DUT signal and inputs it to the signal amplification unit as the second DUT signal, according to the measurement mode. The signal following unit generates a second measurement signal that follows the second DUT signal. The signal amplification unit amplifies the first DUT signal based on the second measurement signal to generate a first measurement signal. Since the forward and reverse measurements share the signal amplification unit and the signal following unit, the forward measurement value of the forward measurement signal and the reverse measurement value of the reverse measurement signal are obtained based on the first and second measurement signals to calculate the noise-reduced measurement value, accurately eliminating voltage errors caused by offset voltage and thermal noise voltage.

Description

Technical Field

[0001] This invention relates to the field of semiconductor testing technology, and more particularly to voltage sampling amplifier circuits and measurement methods. Background Technology

[0002] With the development of semiconductor processing and advanced manufacturing processes, in order to meet the requirements of nanoscale wafer processing and the development of new packaging technologies, it is necessary to test tiny voltage signals at the nanovolt level. During the test, the current value of the signal is required to be very small in order to avoid the influence of the measurement system on the object under test. Currently, voltage sampling amplifier circuits are mostly used to amplify small signals.

[0003] Existing voltage sampling circuits often employ precision operational amplifier chips to amplify signals. However, due to the offset voltage between the positive and negative input terminals of these chips, when the measured signal is a small signal at the microvolt level, the offset voltage is also amplified synchronously during sampling and amplification, potentially even overriding the input signal and causing measurement failures for nanovolt-level signals. Furthermore, when amplifying small voltages, such as from nanovolt to microvolt levels to 1mV to 1V, high-resistance resistors are inevitably used in such high-gain circuits. These high-resistance resistors generate thermal noise as the signal is amplified and the circuit temperature rises. This thermal noise interferes with the measured signal, easily leading to measurement failures for nanovolt-level signals. Summary of the Invention

[0004] The purpose of this invention is to provide a voltage sampling amplifier circuit and measurement method to avoid excessive voltage error in the output voltage caused by the offset voltage at the positive and negative input terminals and the thermal noise voltage of the gain resistor, which could lead to measurement failure.

[0005] The voltage sampling amplification circuit and measurement method provided in this application adopt the following technical solution: The voltage sampling amplifier circuit includes a measurement signal selection unit, a signal amplification unit, and a signal follower unit; The signal amplification unit is connected to the measurement signal selection unit and the signal follower unit. It is used to amplify the first test signal from the measurement signal selection unit by referring to the second measurement signal from the signal follower unit, and generate the first measurement signal. The signal follower unit is connected to the measurement signal selection unit and the signal amplification unit. It is used to generate a second measurement signal based on the second test signal from the measurement signal selection unit. The signal follower unit operates in follower mode. In the forward measurement, the first input signal connected to the measurement signal selection unit is used as the first test signal and connected to the signal amplification unit; the second input signal connected to the measurement signal selection unit is used as the second test signal and connected to the signal following unit; the first measurement signal and the second measurement signal are used to obtain the forward measurement signal to generate the forward measurement value. During reverse measurement, the second input signal connected to the measurement signal selection unit is used as the first signal to be measured and connected to the signal amplification unit; the first input signal connected to the measurement signal selection unit is used as the second signal to be measured and connected to the signal following unit; the first measurement signal and the second measurement signal are used to obtain the reverse measurement signal to generate the reverse measurement value; The forward and reverse measurements are used to calculate the noise-reduced measurement.

[0006] By adopting the above technical solution, in forward measurement, the first input signal is used as the first test signal and the second input signal is used as the second test signal. The first and second measurement signals are obtained through a signal amplification unit and a signal follower unit, thereby generating a forward measurement signal and a forward measurement value. In reverse measurement, the second input signal is used as the first test signal and the first input signal is used as the second test signal. The first and second measurement signals are obtained through a signal amplification unit and a signal follower unit, thereby generating a reverse measurement signal and a reverse measurement value.

[0007] In this case, since the forward and reverse measurements share the same signal amplification unit and signal follower unit, and the offset voltage and thermal noise voltage are consistent, the output voltage error is consistent. Therefore, in this case, the voltage error is eliminated by the noise-reduced measurement value obtained from the forward and reverse measurement values, thus ensuring the accuracy of the final measurement.

[0008] Optionally, the measurement signal selection unit includes a first switching switch and a second switching switch. During forward measurement, the first switching switch uses the first input signal as the first signal to be measured and connects it to the signal amplification unit, and the second switching switch uses the second input signal as the second signal to be measured and connects it to the signal following unit. During reverse measurement, the first switch connects the second input signal as the first signal to be measured to the signal amplification unit, and the second switch connects the first input signal as the second signal to be measured to the signal follower unit.

[0009] By adopting the above technical solution and setting a first switching switch and a second switching switch, it is easier to switch the signal during forward measurement and reverse measurement.

[0010] Optionally, the first switching switch includes a sub-switch, and the sub-switch in the first switching switch includes a first terminal, a second terminal and a third terminal. The first terminal is connected to a first input signal, the second terminal is connected to a second input signal, and the third terminal is connected to a signal amplification unit. In the forward measurement, the third terminal is connected to the first terminal, and in the reverse measurement, the third terminal is connected to the second terminal. Furthermore, the second switch includes a sub-switch, which comprises a fourth terminal, a fifth terminal, and a sixth terminal. The fourth terminal is connected to the second input signal, the fifth terminal is connected to the first input signal, and the sixth terminal is connected to the signal amplification unit. Specifically, during forward measurement, the sixth terminal is connected to the fourth terminal; during reverse measurement, the sixth terminal is connected to the fifth terminal. Alternatively, The first switching switch includes a first sub-switch and a second sub-switch. The first sub-switch is connected to a first input signal, and the second sub-switch is connected to a second input signal. The second switching switch includes a third sub-switch and a fourth sub-switch. The third sub-switch is connected to the first input signal, and the fourth sub-switch is connected to the second input signal. During forward measurement, the first sub-switch and the fourth sub-switch are turned on, and during reverse measurement, the second sub-switch and the third sub-switch are turned on.

[0011] By adopting the above technical solution, when both the first and second switching switches use a sub-switch, during forward measurement, the first switching switch transmits the first input signal as the first test signal to the signal amplification unit through its first and second conducting terminals, while the second switching switch transmits the second input signal as the second test signal to the signal follower unit through its fourth and fifth conducting terminals. During reverse measurement, the first switching switch transmits the second input signal as the first test signal to the signal amplification unit through its first and third conducting terminals, while the second switching switch transmits the first input signal as the second test signal to the signal follower unit through its fourth and sixth conducting terminals. This solution, using both the first and second switching switches, facilitates forward and reverse measurement. Each of the first and second switching switches can be implemented using a single-pole double-throw switch, ensuring that more complex circuits can be controlled with fewer components.

[0012] When the first and second switching switches employ two sub-switches, during forward measurement, the first input signal is transmitted as the first test signal to the signal amplification unit via the conducting first sub-switch, and the second input signal is transmitted as the second test signal to the signal follower unit via the conducting fourth sub-switch. During reverse measurement, the second input signal is transmitted as the first test signal to the signal amplification unit via the conducting second sub-switch, and the first input signal is transmitted as the second test signal to the signal follower unit via the conducting third sub-switch. This can be achieved using two single-pole single-throw switches, ensuring that different signals are transmitted to the signal amplification unit and signal follower unit through different switches, minimizing interference between signals and simplifying circuit implementation.

[0013] Optionally, the signal amplification unit has a first input terminal, a second input terminal, and a first output terminal; the signal follower unit has a third input terminal and a second output terminal. The third input terminal is used to receive the second signal under test, the second output terminal is used to output the second measurement signal generated following the second signal under test, the first input terminal is used to receive the first signal under test, the second input terminal is used to receive the second measurement signal as a reference to generate the first measurement signal, and the first output terminal is used to output the first measurement signal.

[0014] By adopting the above technical solution, the signal following unit outputs a second measurement signal following the second test signal received at the third input terminal through the second output terminal. The signal amplification unit amplifies the first test signal received at the first input terminal using the second measurement signal received at the second input terminal as a reference, and outputs the generated first measurement signal through the first output terminal. This achieves the generation of the first and second measurement signals during forward and reverse measurement processes, thereby obtaining the forward and reverse measurement signals.

[0015] Optionally, the signal amplification unit includes a first operational amplifier, a first resistor, and a second resistor; The non-inverting input of the first operational amplifier serves as the first input to receive the first signal to be measured, and the output of the first operational amplifier serves as the first output to output the first measurement signal. The output of the first operational amplifier is also connected to the inverting input of the first operational amplifier and the first end of the second resistor through a first resistor. The second end of the second resistor serves as the second input.

[0016] Through the above technical solution, the signal amplification unit amplifies the first signal to be measured according to the second measurement signal to obtain the first measurement signal, wherein the amplification gain is related to the resistance values ​​of the first resistor and the second resistor.

[0017] Optionally, the signal follower unit includes a second operational amplifier, the non-inverting input of the second operational amplifier is used as a third input to receive the second signal to be measured, the inverting input of the second operational amplifier is connected to the output of the second operational amplifier to ensure that the second operational amplifier operates in follower mode, and the output of the second operational amplifier is used as a second output to output the second measurement signal.

[0018] With the above technical solution, the gain of the second operational amplifier in the signal following unit is 1, and the signal following unit generates a second measurement signal to follow based on the second signal to be measured.

[0019] Optionally, the first resistor includes multiple first gain resistors connected in series, with the input terminal of the first gain resistor serving as the first terminal of the first resistor, and the output terminal of the last first gain resistor serving as the second terminal of the first resistor; and / or, The second resistor includes multiple second gain resistors connected in series. The input terminal of the first second gain resistor serves as the first terminal of the second resistor, and the output terminal of the last second gain resistor serves as the second terminal of the second resistor.

[0020] Through the above technical solution, the first resistor can be formed by multiple first gain resistors connected in series, and the second gain resistor can also be formed by multiple second gain resistors connected in series, supporting the combination of the first gain resistor and the second gain resistor.

[0021] The present invention also provides a measurement method applied to the voltage sampling amplification circuit described above, comprising the following steps: According to the measurement mode, one of the first input signal and the second input signal connected to the measurement signal selection unit is used as the first signal to be measured and sent to the signal amplification unit to generate the first measurement signal, and the other is used as the second signal to be measured and sent to the signal follower unit to generate the second measurement signal. Acquire a first measurement signal and a second measurement signal, and generate a positive measurement signal or a reverse measurement signal corresponding to the measurement mode based on the first measurement signal and the second measurement signal; The forward measurement value is obtained from the forward measurement signal, and the reverse measurement value is obtained from the reverse measurement signal. The noise reduction measurement value is calculated based on the forward and reverse measurement values.

[0022] Through the above technical solution, when the measurement mode is forward measurement, the first input signal and the second input signal are used as the first and second signals to be measured, respectively, to obtain the first measurement signal and the second measurement signal, generating a forward measurement signal and obtaining a forward measurement value. When the measurement mode is reverse measurement, the second input signal and the first input signal are used as the first and second signals to be measured, respectively, to obtain the first and second measurement signals, generating a reverse measurement signal and obtaining a reverse measurement value. Since the offset voltage and the thermal noise voltage are consistent, the output voltage error is consistent in both forward and reverse measurements. Therefore, the noise-reduced measurement value obtained based on the forward and reverse measurement values ​​has eliminated the aforementioned error.

[0023] Optionally, the measurement signal selection unit includes a first switching switch and a second switching switch; According to the measurement mode, one of the first input signal and the second input signal is used as the first signal to be measured to generate a first measurement signal, and the other is used as the second signal to be measured to generate a second measurement signal; the first measurement signal and the second measurement signal are acquired, and a positive measurement signal or a negative measurement signal corresponding to the measurement mode is generated based on the first measurement signal and the second measurement signal, including: During forward measurement, the first input signal is used as the first test signal and the second input signal is used as the second test signal. The first switching switch connects the first input signal as the first test signal to the signal amplification unit to generate the first measurement signal, and the second switching switch connects the second input signal as the second test signal to the signal follower module to generate the second measurement signal. The first measurement signal and the second measurement signal are collected, and the forward measurement signal is obtained based on the first measurement signal and the second measurement signal. During reverse measurement, the second input signal is used as the first test signal, and the first input signal is used as the second test signal. The first switch connects the second input signal as the first test signal to the signal amplification unit to generate the first measurement signal, and the second switch connects the first input signal as the second test signal to the signal follower module to generate the second measurement signal. The first measurement signal and the second measurement signal are acquired, and the reverse measurement signal is obtained based on the first measurement signal and the second measurement signal.

[0024] Optionally, the noise reduction measurement value is calculated based on the forward and reverse measurement values ​​by: calculating the difference between the forward and reverse measurement values, dividing the difference by 2, and obtaining the noise reduction measurement value.

[0025] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention uses a measurement signal selection unit to select one of the first input signal and the second input signal as the first test signal and the other as the second test signal, thereby realizing forward or reverse measurement of the circuit under test and obtaining a forward measurement signal or a reverse measurement signal.

[0026] 2. In the forward and reverse measurement modes of this invention, the signal amplification unit and the signal follower unit are shared. The current flowing through the first resistor and the second resistor is the same, making the thermal noise voltage corresponding to the first resistor the same during both forward and reverse measurements. Similarly, the thermal noise voltage of the second resistor is the same, ensuring that the offset voltage and thermal noise voltage in the signal amplification unit and the signal follower unit are consistent. Therefore, the output voltage error is consistent. In this invention, the voltage error is eliminated based on the denoised measurement value obtained from the forward and reverse measurement values, ensuring the accuracy of the final denoised measurement value. Therefore, when both the first and second input signals are small currents, the operational amplifiers in the signal amplification unit and the signal follower unit are configured to support small current inputs, enabling sampling of small voltage signals.

[0027] 3. In this invention, the first resistor and the second resistor, while meeting the gain requirements of the signal amplification unit, can reduce the error caused by thermal noise voltage on the forward measurement signal during forward measurement and the error caused by thermal noise voltage on the reverse measurement signal during reverse measurement by reducing the resistance values ​​of the first resistor and the second resistor. This improves the accuracy of obtaining the forward measurement value from the forward measurement signal and the reverse measurement value from the reverse measurement signal, thereby improving the accuracy of the noise-reduced measurement value. Attached Figure Description

[0028] Figure 1 A schematic diagram of a voltage sampling amplifier circuit provided in the first embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the measurement signal selection unit in the middle; Figure 3 for Figure 1 A circuit diagram of a medium voltage sampling amplifier circuit during forward sampling; Figure 4 for Figure 1 A circuit diagram of a medium voltage sampling amplifier circuit during reverse sampling; Figure 5 for Figure 1 Another circuit diagram of the medium voltage sampling amplifier circuit during forward sampling; Figure 6 for Figure 1 Another circuit diagram of the medium voltage sampling amplifier circuit during reverse sampling; Figure 7 for Figure 2 A circuit diagram of a signal amplification unit; Figure 8 for Figure 2 Another circuit diagram of the signal amplification unit; Figure 9 A flowchart of a measurement method provided for a second embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0030] A first embodiment of the present invention provides a voltage sampling amplifier circuit 10. (See reference...) Figure 1 As shown, the voltage sampling amplifier circuit 10 includes a measurement signal selection unit 1, a signal amplification unit 2, and a signal follower unit 3.

[0031] The measurement signal selection unit 1 is connected to the signal amplification unit 2 and the signal follower unit 3. It inputs one of the first input signal vih and the second input signal vil as the first signal to be tested into the signal amplification unit 2, and the other as the second signal to be tested into the signal follower unit 3. The first input signal vih and the second input signal vil can be obtained by sampling the signals at both ends of the circuit under test 20, meaning they can be input through the circuit under test 20. In this case, the circuit under test 20 can be connected to the measurement signal selection unit 1.

[0032] The signal following unit 3 is connected to the measurement signal selection unit 1 and the signal amplification unit 2. The signal following unit 3 operates in the following mode. The signal following unit 3 generates a second measurement signal vol that follows the second measurement signal according to the second measurement signal from the measurement signal selection unit 1. The second measurement signal vol is used as the reference signal of the signal amplification unit 2.

[0033] The signal amplification unit 2 is connected to the measurement signal selection unit 1 and the signal follower unit 3. The signal amplification unit 2 amplifies the first test signal from the measurement signal selection unit 1 by referring to the second measurement signal vol from the signal follower unit 3, and generates the first measurement signal voh.

[0034] The voltage sampling amplification circuit 10 in this embodiment has two measurement modes. In the forward measurement mode, the measurement signal selection unit 1 transmits the second input signal *vil* as the second signal to be measured to the signal follower unit 3, so that the signal follower unit 3 obtains the second measurement signal *vol*. The measurement signal selection unit 1 also transmits the first input signal *vih* as the first signal to be measured to the signal amplification unit 2, so that the signal amplification unit modulates the first signal to be measured according to the second measurement signal *vol* to obtain the first measurement signal *voh*. The measurement processing module 30 obtains the forward measurement signal *out* based on the first measurement signal *voh* from the signal amplification unit 2 and the second measurement signal *vol* from the signal follower unit 3. 正 To generate positive measurement values .

[0035] When the measurement mode is reverse measurement, the measurement signal selection unit 1 uses the first input signal vih as the second test signal and transmits it to the signal follower unit 3 so that the signal follower unit 3 can obtain the second measurement signal vol. The measurement signal selection unit 1 uses the second input signal vih as the first test signal and transmits it to the signal amplification unit 2 so that the signal amplification unit 2 can modulate the first test signal with the second measurement signal vol as a reference to obtain the first measurement signal voh. The measurement processing module 30 obtains the reverse measurement signal out based on the first measurement signal voh from the signal amplification unit 2 and the second measurement signal vol from the signal follower unit 3. 反 To generate reverse measurement values .

[0036] Furthermore, the measurement processing module 30 calculates the positive measurement value. and reverse measurement value Calculate the noise reduction measurement value In the voltage sampling amplifier circuit 10, since the forward and reverse measurements share the signal amplification unit 2 and the signal follower unit 3, the voltage error caused by the offset voltage across the amplifiers in the signal amplification unit 2 and the signal follower unit 3 is the same during forward measurement as during reverse measurement. The thermal noise voltage of the resistor in the signal amplification unit 2 is also the same during forward measurement as during reverse measurement. In other words, the offset voltage and thermal noise voltage in the signal amplification unit 2 and the signal follower unit 3 are consistent, resulting in consistent output voltage errors. Therefore, in this case, based on the forward measurement value... and reverse measurement value The obtained noise reduction measurement value Eliminating voltage errors ensures the accuracy of the final measurement.

[0037] In some embodiments, see Figure 2The measurement signal selection unit 1 includes a first switching switch and a second switching switch. During forward measurement, the first switching switch connects the first input signal vih as the first signal to be measured to the signal amplification unit, and the second switching switch connects the second input signal vil as the second signal to be measured to the signal follower unit. During reverse measurement, the first switching switch connects the second input signal vil as the first signal to be measured to the signal amplification unit, and the second switching switch connects the first input signal vih as the second signal to be measured to the signal follower unit.

[0038] In this embodiment, by setting a first switching switch and a second switching switch, during forward measurement, the first switching switch transmits the first input signal vih, and the second switching switch transmits the second input signal vil; during reverse measurement, the second switching switch transmits the second input signal vil, and the second switching switch transmits the first input signal vih. This makes it easier to switch signals between forward and reverse measurements. During each measurement, both the first and second switching switches transmit only one signal, avoiding mutual interference between signals.

[0039] In some examples, reference Figure 3 and Figure 4 As shown, when the first switch and the second switch each include a sub-switch, the sub-switch sw0 of the first switch has a first terminal, a second terminal, and a third terminal. The first terminal is connected to the first input signal vih from the circuit under test 20, the second terminal is connected to the second input signal vil from the circuit under test 20, and the third terminal is connected to the signal amplification unit 2. The sub-switch sw1 of the second switch has a fourth terminal, a fifth terminal, and a sixth terminal. The fourth terminal is connected to the second input signal vil from the circuit under test 20, the fifth terminal is connected to the first input signal vih from the circuit under test 20, and the sixth terminal is connected to the signal follower unit 3.

[0040] When the signals at both ends of the circuit under test 20 are sampled, that is, when the circuit under test 20 provides the first input signal vih and the second input signal vil, the circuit under test 20 outputs the first input signal vih and the second input signal vil. There is an original voltage difference V(vin) between the first input signal vih and the second input signal vil, which is V(vin) = V(vih) - V(vil). During forward measurement, the sub-switch sw0 in the first switching switch connects the third terminal to the first terminal and disconnects the third terminal from the second terminal. The first input signal vih is transmitted to the signal amplification unit 2 as the first test signal. The sub-switch sw1 in the second switching switch connects the sixth terminal to the fourth terminal and disconnects the sixth terminal from the fifth terminal. The second input signal vil is transmitted to the signal amplification unit 2 as the second test signal. The forward measurement signal out is obtained through the first measurement signal voh and the second measurement signal vol. 正 To generate positive measurement values This positive measurement value It is a positive number.

[0041] During reverse measurement, sub-sw0 in the first switching switch connects the third terminal to the second terminal and disconnects the third terminal from the first terminal, transmitting the second input signal vil as the first test signal to signal amplification unit 2. Sub-sw1 in the second switching switch connects the sixth terminal to the fifth terminal and disconnects the sixth terminal from the fourth terminal, transmitting the first input signal vih as the second test signal to signal amplification unit 2. The reverse measurement signal out is obtained through the first measurement signal voh and the second measurement signal vol. 反 To generate reverse measurement values The reverse measurement value It is a negative number.

[0042] In other embodiments, reference is made to... Figure 5 and Figure 6 As shown, the first and second switching switches each include two sub-switches. The first switching switch includes a first sub-switch sw11 and a second sub-switch sw12. The first sub-switch sw11 is connected to the first input signal vih, and the second sub-switch sw12 is connected to the second input signal vil. The second switching switch includes a third sub-switch sw21 and a fourth sub-switch sw22. The third sub-switch sw21 is connected to the first input signal vih, and the second sub-switch sw22 is connected to the second input signal vil. During forward measurement, the first sub-switch sw11 and the fourth sub-switch sw21 are turned on, so that the first input signal vih is transmitted to the signal amplification unit 2, and the second input signal vil is transmitted to the signal follower unit 3. During reverse measurement, the second sub-switch sw12 and the third sub-switch sw21 are turned on, so that the second input signal vil is transmitted to the signal amplification unit 2, and the first input signal vih is transmitted to the signal follower unit 3.

[0043] Specifically, for forward measurements, please refer to [link / reference]. Figure 5 In the first switching switch, the first sub-switch sw11 is turned on, and the second sub-switch sw12 is turned off. In the second switching switch, the fourth sub-switch sw22 is turned on, and the third sub-switch sw21 is turned off. The first input signal vih is passed to the signal amplification unit 2 as the first test signal, and the second input signal vil is passed to the signal amplification unit 2 as the second test signal. The positive measurement signal out is obtained through the first measurement signal voh and the second measurement signal vol. 正 To generate positive measurement values This positive measurement value It is a positive number.

[0044] For reverse measurement, please refer to Figure 6In the first switching switch, the first sub-switch sw11 is open and the second sub-switch sw12 is open; in the second switching switch, the third sub-switch sw21 is open and the fourth sub-switch sw22 is open. The second input signal vil is passed to the signal amplification unit 2 as the first test signal, and the first input signal vih is passed to the signal amplification unit 2 as the second test signal. The inverse measurement signal out is obtained through the first measurement signal voh and the second measurement signal vol. 反 To generate reverse measurement values The reverse measurement value It is a negative number.

[0045] In this embodiment, both the first and second switching switches operate using two sub-switches, ensuring that each sub-switch can only transmit one type of electrical signal. This avoids interference during the switching of different signals on the same line, guaranteeing the accuracy of signal transmission. Furthermore, by changing the on / off states of the first sub-switch sw11, the second sub-switch sw12, the third sub-switch sw21, and the fourth sub-switch sw22, the forward and reverse measurements of the combination of the first input signal vih and the second input signal vil are achieved.

[0046] In some embodiments, when both the first and second switching switches use a single sub-switch, the specific wiring reference is provided. Figure 3 and Figure 4 As shown, the first terminal of sub-sw0 in the first switching switch is connected to the fifth terminal of sub-sw1 in the second switching switch, and the first input signal vih is connected through the connection between the first terminal and the fifth terminal; the second terminal of sub-sw0 in the first switching switch is connected to the fourth terminal of sub-sw1 in the second switching switch, and the second input signal vil is connected through the connection between the second terminal and the fourth terminal, thereby optimizing the circuit layout.

[0047] When both the first and second changeover switches use two sub-switches, refer to the specific wiring diagram. Figure 5 and Figure 6 As shown, the first sub-switch sw11 in the first switching switch is connected to the third sub-switch sw21 in the second switching switch and then connected to the first input signal vih, and the second sub-switch sw12 in the first switching switch is connected to the fourth sub-switch sw22 in the second switching switch and then connected to the second input signal vil, which can also optimize the circuit layout.

[0048] In some embodiments, continue to refer to Figure 1Signal amplification unit 2 has a first input terminal, a second input terminal, and a first output terminal; signal following unit 3 has a third input terminal and a second output terminal. The third input terminal of signal following unit 3 receives a second test signal from measurement signal selection unit 1, and the second output terminal outputs a second measurement signal vol generated by following the second test signal. In signal amplification unit 2, the first input terminal receives the first test signal from measurement signal selection unit 1, and the second input terminal receives the second measurement signal vol from signal following unit 3. Signal amplification unit 2 generates a first measurement signal using the second measurement signal vol as a reference, and the first output terminal outputs a first measurement signal voh generated by amplifying the first test signal based on the second measurement signal vol.

[0049] In this embodiment, the same signal amplification unit 2 and signal following unit 3 are used in both forward and reverse measurements. The signal following unit 3 outputs a second measurement signal vol, which follows the second test signal, through its second output terminal, based on the second test signal input at the third input terminal. The signal amplification unit 2 amplifies the first test signal input at the first input terminal using the second measurement signal vol as a reference, and outputs a first measurement signal voh through its first output terminal. This enables the generation of the first measurement signal voh and the second measurement signal vol during both forward and reverse measurements, thereby obtaining the forward measurement signal out. 正 and reverse measurement signal out 反 .

[0050] As a detailed case study, refer to Figures 3 to 6 As shown, the signal amplification unit 2 includes a first operational amplifier OPA0, a first resistor R1, and a second resistor R0. The non-inverting input of the first operational amplifier OPA0 serves as the first input of the signal amplification unit 2 to receive the first signal to be measured, and the output of the first operational amplifier OPA0 serves as the first output of the signal amplification unit 2 to output the first measurement signal voh. The output of the first operational amplifier OPA0 is connected to the first terminal of the first resistor R1, the second terminal of the first resistor R1 is connected to the inverting input of the first operational amplifier OPA0 to transmit the first feedback signal vfbh, ​​and the second terminal of the first resistor R1 is connected to the first terminal of the second resistor R0. The second terminal of the second resistor R0 serves as the second input of the signal amplification unit 2 to receive the second measurement signal vol from the signal follower unit 3.

[0051] Continue to refer to Figures 3 to 6The signal follower unit 3 includes a second operational amplifier OPA1. The non-inverting input of the second operational amplifier OPA1 serves as the third input of the signal follower unit 3 to receive the second test signal from the measurement signal selection unit 1. The inverting input of the second operational amplifier OPA1 is connected to the output of the second operational amplifier OPA1 to transmit the second feedback signal vfbl, ensuring that the second operational amplifier OPA1 operates in follower mode. The output of the second operational amplifier OPA1 serves as the second output of the signal follower unit 3 to output the second measurement signal vol.

[0052] In this case, the amplification gain g of signal amplification unit 2 is determined by the first resistor R1 and the second resistor R0, that is, g = (R0 + R1) / R0; the amplification gain of signal follower unit 3 is 1, and the second measured signal follows the change of the second measured signal. Assume that the first operational amplifier OPA0 has an offset error e0, the second operational amplifier OPA1 has an offset error e1, and the second resistor R0 has a thermal noise voltage vt00. The thermal noise voltage vt01 of the first resistor R1, under constant ambient temperature, depends on the current I flowing through the second resistor R0. R0 The magnitude of vt01 depends on the current I flowing through the first resistor R1. R1 The magnitude of the voltage is the same in both forward and reverse measurements. The current flowing through the first resistor R1 and the second resistor R0 are the same. Therefore, the thermal noise voltage introduced by the first resistor R1 and the second resistor R0 are the same in both forward and reverse measurements. Furthermore, the operational amplifier's offset error remains unchanged in both forward and reverse measurements. Thus, due to the offset error and the thermal noise voltage introduced by the resistors, the voltage is the same in both forward and reverse measurements. In summary, the forward measurement voltage value is... The reverse measured voltage value is .

[0053] Because the thermal noise voltage introduced by the resistor, under constant ambient temperature, depends on the magnitude of the current I00 flowing through the resistor, the minimum resistance values ​​of the second resistor R0 and the first resistor R1 can be selected to reduce the thermal noise voltage while ensuring gain. In other words, the circuit in this design supports adjusting the resistance values ​​of the first resistor R1 and the second resistor R0 to reduce the overall thermal noise voltage. Furthermore, since the current I flowing through the second resistor R0 increases during forward and reverse measurements... R0 Therefore, in this case, the overall error caused by thermal noise pressure and offset error during forward measurement is equal to the overall error caused by thermal noise pressure and offset error during reverse measurement.

[0054] During forward measurement, the voltage sampling amplifier circuit 10 outputs a first measurement signal voh and a second measurement signal vol. The measurement processing module 30 obtains the forward measurement signal out based on the first measurement signal voh and the second measurement signal vol. 正 Thus, a positive measurement value is obtained. .

[0055] During reverse measurement, the voltage sampling amplifier circuit 10 outputs a first measurement signal voh and a second measurement signal vol. The measurement processing module 30 obtains the reverse measurement signal out based on the first measurement signal voh and the second measurement signal vol. 反 This leads to the reverse measurement value. .

[0056] Subsequently, the measurement processing module 30 calculates the positive measurement value. and reverse measurement value Then the noise reduction measurement value can be obtained. Specifically, this involves calculating the positive measurement value. The reverse measurement value The difference between , the difference Divide by 2 to obtain the noise reduction measurement value. In other words, since the overall error caused by thermal noise pressure and offset error during forward measurement is equal to the overall error caused by thermal noise pressure and offset error during reverse measurement, the forward measurement value is used. and reverse measurement value By taking the difference, the influence of measurement error can be eliminated.

[0057] As a detailed case study, based on the aforementioned cases, and referring to... Figure 7 As shown, the first resistor R1 comprises n first gain resistors R11, ..., R1n (n≥2) connected in series. The input terminal of the first first gain resistor R11 serves as the first terminal of the first resistor R1, and the output terminal of the last first gain resistor R1n serves as the second terminal of the first resistor R1. This example supports the effect of multiple first gain resistors connected in series to form the overall first resistor R1, which is suitable for scenarios where the overall resistance value of the first resistor R1 needs to be frequently adjusted.

[0058] As a detailed case study, based on the aforementioned cases, and referring to... Figure 8As shown, the second resistor R0 includes n interconnected second gain resistors R01, ..., R0n (n≥2). The input terminal of the first second gain resistor R01 serves as the first terminal of the second resistor R0, and the output terminal of the last second gain resistor R0n serves as the second terminal of the second resistor R0. This example supports the effect of multiple second gain resistors connected in series to form the overall second resistor R0, which is suitable for scenarios where the overall resistance value of the second resistor R0 needs to be frequently adjusted.

[0059] This embodiment also supports a first resistor R1 formed by multiple first gain resistors connected in series, and a second gain resistor R0 formed by multiple second gain resistors connected in series. It supports the combination of first gain resistors and second gain resistors. The resistance values ​​of these first gain resistors can be the same or different, and the resistance values ​​of the second gain resistors can be the same or different.

[0060] In this embodiment, when both the first input signal vih and the second input signal vil are small currents, the first operational amplifier OPA0 in the signal amplification unit 2 and the second operational amplifier OPA1 in the signal follower unit 3 are both configured to support small current inputs. At the same time, while ensuring that the gain g of the signal amplification unit 2 remains unchanged, the resistance values ​​of the first resistor R1 and the second resistor R0 in the signal amplification unit 2 are adjusted to reduce the thermal noise voltage generated by the first resistor R1 and the second resistor R0 during operation. This ensures accurate detection of the first measurement signal voh and the second measurement signal vol, achieves sampling of small voltages, and avoids the interference caused by thermal noise voltage from overwhelming the small input current, thus preventing the detection of the first measurement signal voh and the second measurement signal vol from failing.

[0061] The second embodiment of the present invention provides a measurement method applied to the voltage sampling amplifier circuit 10 described above, such as... Figure 9 As shown, it includes the following steps: Step 101: According to the measurement mode, one of the first input signal vih and the second input signal vil of the measurement signal selection unit 1 is used as the first test signal and sent to the signal amplification unit 2 to generate the first measurement signal voh, and the other is used as the second test signal and sent to the signal follower unit 3 to generate the second measurement signal vol. Step 102: Acquire the first measurement signal voh and the second measurement signal vol, and generate a positive measurement signal out corresponding to the measurement mode based on the first measurement signal voh and the second measurement signal vol. 正 Or reverse measurement signal out 反 ; Step 103, based on the positive measurement signal out 正 Obtain positive measurement value According to the reverse measurement signal out反 Obtain the reverse measurement value ; Step 104, based on the positive measurement value and reverse measurement value The noise reduction measurement value was calculated. .

[0062] When the measurement mode is forward measurement, the first input signal vih and the second input signal vil are used as the first and second signals to be measured, respectively, to obtain the first measurement signal voh and the second measurement signal vol, and generate the forward measurement signal out. 正 To obtain positive measurement values When the measurement mode is reverse measurement, the second input signal vih and the first input signal vil are used as the first and second signals to be measured, respectively, to obtain the first measurement signal voh and the second measurement signal vol, and to generate the reverse measurement signal out. 反 The reverse measurement value is obtained. To obtain positive measurement values and reverse measurement value This can be achieved through an analog-to-digital converter (ADC) circuit, such as a SAR (Successive Approximation) mode ADC circuit or a hybrid ADC circuit; no specific limitation is made here. Since the output voltage error caused by offset voltage and thermal noise voltage is consistent in both forward and reverse measurements, it can be determined based on the forward measurement value. and reverse measurement value The obtained noise reduction measurement value The error effects caused by offset voltage and thermal noise voltage have been eliminated.

[0063] Step 104 includes: calculating the positive measurement signal out. 正 positive measurement value With the reverse measurement signal out 反 Reverse measurement value The difference between Divide the difference by 2 to obtain the noise reduction measurement value. .

[0064] In both forward and reverse measurement modes, the signal amplification unit 2 and the signal follower unit 3 share the same current flowing through the first resistor R1 and the second resistor R2. This ensures that the thermal noise voltages generated by the first resistor R1 and the second resistor R2 are the same, resulting in consistent output voltage errors caused by the offset voltage and thermal noise voltage in the signal amplification unit 2 and the signal follower unit 3, based on the forward measurement value. and reverse measurement value The obtained noise reduction measurement value Eliminating voltage errors ensures the final noise-reduced measurement value. accuracy.

[0065] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A voltage sampling amplification circuit, characterized by, It includes a measurement signal selection unit, a signal amplification unit, and a signal follower unit; The signal amplification unit is connected to the measurement signal selection unit and the signal following unit, and is used to amplify the first signal to be measured from the measurement signal selection unit with reference to the second measurement signal from the signal following unit to generate the first measurement signal. The signal following unit is connected to the measurement signal selection unit and the signal amplification unit, and is used to generate the second measurement signal based on the second test signal from the measurement signal selection unit. The signal following unit operates in a following mode. In the forward measurement, the first input signal connected to the measurement signal selection unit is used as the first signal to be measured and connected to the signal amplification unit; the second input signal connected to the measurement signal selection unit is used as the second signal to be measured and connected to the signal following unit; the first measurement signal and the second measurement signal are used to obtain a forward measurement signal to generate a forward measurement value. During reverse measurement, the second input signal connected to the measurement signal selection unit is used as the first signal to be measured and connected to the signal amplification unit; the first input signal connected to the measurement signal selection unit is used as the second signal to be measured and connected to the signal following unit; the first measurement signal and the second measurement signal are used to obtain a reverse measurement signal to generate a reverse measurement value; The forward measurement value and the reverse measurement value are used to calculate the noise reduction measurement value.

2. The voltage sampling amplifier circuit of claim 1, wherein, The measurement signal selection unit includes a first switching switch and a second switching switch; During forward measurement, the first switching switch connects the first input signal as the first signal to be measured to the signal amplification unit, and the second switching switch connects the second input signal as the second signal to be measured to the signal following unit. During reverse measurement, the first switching switch connects the second input signal as the first signal to be tested to the signal amplification unit, and the second switching switch connects the first input signal as the second signal to be tested to the signal following unit.

3. The voltage sampling amplifier circuit according to claim 2, characterized in that, The first switching switch includes a sub-switch, and the sub-switch in the first switching switch includes a first terminal, a second terminal, and a third terminal. The first terminal is connected to the first input signal, the second terminal is connected to the second input signal, and the third terminal is connected to the signal amplification unit. In the forward measurement, the third terminal is connected to the first terminal, and in the reverse measurement, the third terminal is connected to the second terminal. Furthermore, the second switching switch includes a sub-switch, which comprises a fourth terminal, a fifth terminal, and a sixth terminal. The fourth terminal is connected to the second input signal, the fifth terminal is connected to the first input signal, and the sixth terminal is connected to the signal following unit. Specifically, during forward measurement, the sixth terminal is connected to the fourth terminal; during reverse measurement, the sixth terminal is connected to the fifth terminal. Alternatively, The first switching switch includes a first sub-switch and a second sub-switch, the first sub-switch being connected to the first input signal and the second sub-switch being connected to the second input signal; the second switching switch includes a third sub-switch and a fourth sub-switch, the third sub-switch being connected to the first input signal and the fourth sub-switch being connected to the second input signal; wherein, during forward measurement, the first sub-switch and the fourth sub-switch are turned on, and during reverse measurement, the second sub-switch and the third sub-switch are turned on.

4. The voltage sampling amplifier circuit of claim 1, wherein, The signal amplification unit has a first input terminal, a second input terminal, and a first output terminal; the signal follower unit has a third input terminal and a second output terminal. The third input terminal is used to receive the second signal to be tested, and the second output terminal is used to output the second measurement signal generated following the second signal to be tested. The first input terminal is used to receive the first signal under test, the second input terminal is used to receive the second measurement signal as a reference to generate the first measurement signal, and the first output terminal is used to output the first measurement signal.

5. The voltage sampling amplification circuit of claim 4, wherein: The signal amplification unit includes a first operational amplifier, a first resistor, and a second resistor; The non-inverting input terminal of the first operational amplifier serves as the first input terminal to receive the first signal under test, and the output terminal of the first operational amplifier serves as the first output terminal to output the first measurement signal. The output terminal of the first operational amplifier is also connected to the inverting input terminal of the first operational amplifier and the first terminal of the second resistor through the first resistor, and the second terminal of the second resistor serves as the second input terminal.

6. The voltage sampling amplifier circuit of claim 4, wherein: The signal following unit includes a second operational amplifier. The non-inverting input of the second operational amplifier serves as the third input to receive the second signal under test. The inverting input of the second operational amplifier is connected to the output of the second operational amplifier to ensure that the second operational amplifier operates in follower mode. The output of the second operational amplifier serves as the second output to output the second measurement signal.

7. The voltage sampling amplification circuit of claim 5, wherein: The first resistor includes a plurality of first gain resistors connected in series. The input terminal of the first gain resistor is the first terminal of the first resistor, and the output terminal of the last first gain resistor is the second terminal of the first resistor. And / or, The second resistor includes multiple second gain resistors connected in series. The input terminal of the first second gain resistor serves as the first terminal of the second resistor, and the output terminal of the last second gain resistor serves as the second terminal of the second resistor.

8. A measurement method, applied to the voltage sampling amplifier circuit as described in any one of claims 1-7, characterized in that, Includes the following steps: According to the measurement mode, one of the first input signal and the second input signal connected to the measurement signal selection unit is used as the first signal to be measured and sent to the signal amplification unit to generate the first measurement signal, and the other is used as the second signal to be measured and sent to the signal follower unit to generate the second measurement signal. The first measurement signal and the second measurement signal are acquired, and a positive measurement signal or a reverse measurement signal corresponding to the measurement mode is generated based on the first measurement signal and the second measurement signal. A positive measurement value is obtained based on the positive measurement signal, and a negative measurement value is obtained based on the negative measurement signal; The noise reduction measurement value is calculated based on the forward measurement value and the reverse measurement value.

9. The measurement method according to claim 8, characterized in that, The measurement signal selection unit includes a first switching switch and a second switching switch; The step of generating a first measurement signal by using one of the first and second input signals as the first test signal and the other as the second test signal according to the measurement mode; acquiring the first and second measurement signals, and generating a positive or negative measurement signal corresponding to the measurement mode based on the first and second measurement signals, includes: During forward measurement, the first input signal is used as the first test signal and the second input signal is used as the second test signal. The first switching switch connects the first input signal as the first test signal to the signal amplification unit to generate the first measurement signal, and the second switching switch connects the second input signal as the second test signal to the signal following module to generate the second measurement signal. The first measurement signal and the second measurement signal are collected, and the forward measurement signal is obtained based on the first measurement signal and the second measurement signal. During reverse measurement, the second input signal is used as the first test signal, and the first input signal is used as the second test signal. The first switching switch connects the second input signal as the first test signal to the signal amplification unit to generate the first measurement signal, and the second switching switch connects the first input signal as the second test signal to the signal following module to generate the second measurement signal. The first measurement signal and the second measurement signal are collected, and the reverse measurement signal is obtained based on the first measurement signal and the second measurement signal.

10. The measurement method according to claim 9, characterized in that, Based on the forward measurement value and the reverse measurement value, the noise reduction measurement value is calculated as follows: Calculate the difference between the forward measurement value and the reverse measurement value, and divide the difference by 2 to obtain the noise-reduced measurement value.

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