High-precision voltage acquisition module for SOC test

Abstract

The invention relates to the technical field of SOC testing, and particularly discloses a high-precision voltage acquisition module for SOC testing, and the module comprises a signal acquisition module which enables a to-be-acquired voltage to enter a programmable attenuation network, obtains a voltage value of the to-be-acquired voltage, selects an attenuation module based on the voltage value of the to-be-acquired voltage, and outputs the to-be-acquired voltage in a differential signal mode; generating an equation that the differential signal changes along with time, and selecting a gain multiple of a gain module; inputting the amplified differential signal into a GIC filter for filtering, and converting the filtered differential signal into a digital signal; and the self-calibration module is used for generating calibration voltage, realizing multiple output of the calibration voltage and calculating an error coefficient gain error and an offset error. Through the GIC filter, the influence of the filter on the collected voltage is reduced, so that the influence on the DC precision of the whole module is reduced, and the precision of the whole system is improved.

Description

Technical Field

[0001] This invention relates to the field of SOC testing technology, and more specifically to a high-precision voltage acquisition module for SOC testing. Background Technology

[0002] In advanced automated test equipment systems, the high-precision measurement module plays a crucial role, serving as one of the core test components of the entire system. This module possesses voltage measurement capabilities, enabling it to acquire voltage data with extremely high accuracy, thereby providing data support for semiconductor testing needs.

[0003] However, there are several pressing issues with currently widely used conventional voltage acquisition modules. First, conventional voltage acquisition modules lack self-calibration functionality. In long-term practical applications, due to environmental factors, component aging, and other influences, the performance of relevant components gradually drifts over time, inevitably leading to a loss of measurement accuracy and severely impacting the accuracy and reliability of test results. Furthermore, in circuit design, a single-ended structure is typically used to achieve low-noise characteristics. However, this single-ended signal transmission method is extremely sensitive to external interference and easily affected by the surrounding electromagnetic environment, introducing additional noise components and degrading signal quality. Generally, while the designed filter removes clutter, it inevitably introduces some DC noise. More problematic is that this DC noise cannot be effectively compensated for using conventional calibration methods, and its value is unstable, fluctuating with time and changing operating conditions, further exacerbating measurement errors and posing a significant challenge to testing. Summary of the Invention

[0004] The purpose of this invention is to provide a high-precision voltage acquisition module for SOC testing, thereby solving the above-mentioned technical problems.

[0005] The objective of this invention can be achieved through the following technical solutions: A high-precision voltage acquisition module for SOC testing includes: Signal acquisition module: The voltage to be acquired is fed into a preset programmable attenuation network, wherein the programmable attenuation network includes attenuation module A and attenuation module B, the voltage value U of the voltage to be acquired is obtained, the attenuation module is selected based on the voltage value U of the voltage to be acquired, and the voltage to be acquired through the programmable attenuation network is output in the form of a differential signal. Generate an equation U(t) representing the difference signal as a function of time t, and obtain the maximum value U of the difference signal in equation U(t). max and minimum value U min Obtain the conversion range of the ADC [V] - V +], where V - V represents the voltage value of the smallest analog signal that the ADC can resolve. + This represents the voltage value of the largest analog signal that the ADC can resolve, based on the ADC's range [V]. - V + Select the gain factor X for the gain module; The differential signal is input to the gain module and amplified by X times before being output. The amplified differential signal is then input to the GIC filter for filtering. The filtered differential signal is then converted into a digital signal by the ADC. Self-calibration module: Generates calibration voltage based on calibration voltage generator, and outputs calibration voltage at multiples of N through digital potentiometer, where N represents the preset amplification factor; The amplified calibration voltage is filtered by the GIC filter bank and then output to the input section of the voltage acquisition through the switch array; The attenuation level D of the controller is preset, and the attenuation level D is decremented by 1 in sequence. The ADC output signal at each attenuation level is collected and compared with the digital signal in the signal acquisition module. The error coefficients, gain error and offset error of each level are calculated. The voltage obtained by subtracting the gain error and offset error from the voltage to be collected is the high-precision voltage.

[0006] As a further aspect of the present invention: in the signal acquisition module, the method for selecting the attenuation module based on the voltage value U of the voltage to be acquired includes: A first voltage threshold U1 and a second voltage threshold U2 are preset, and 0 < U1 < U2; When the voltage value U < U1, select attenuation module A and let attenuation module A output the voltage to be collected in a direct-through manner; When U1 < U < U2, select attenuation module A to attenuate the voltage value U of the voltage to be collected by 10 times before outputting it; When U > U2, select attenuation module B to attenuate the voltage value U of the voltage to be collected by 100 times before outputting it.

[0007] As a further aspect of the present invention: in the signal acquisition module, based on the ADC range [V - V + Methods for selecting the gain factor X of the gain module include: If the initial gain factor CX is preset and CX=1, and the constraint condition is met... Update the initial gain factor to CX+1, and repeat the above operation until the constraint is no longer met. Then set the gain factor X to the initial gain factor at the time of stopping.

[0008] As a further aspect of the present invention: in the signal acquisition module, a limit voltage is preset, and when the voltage value U of the voltage to be acquired is greater than the limit voltage, the subsequent steps are stopped.

[0009] As a further aspect of the present invention: in the self-calibration module, when the filtered differential signal is converted into a digital signal by the ADC, the temperature of the entire system is kept constant.

[0010] As a further aspect of the present invention: in the self-calibration module, when the calibration voltage is output as a multiple of N by means of a digital potentiometer, N ≤ X is ensured.

[0011] As a further aspect of the present invention: in the signal acquisition module, if the minimum value U of the differential signal... min >0, change the constraint to X×U max <V + .

[0012] As a further aspect of the present invention: in the self-calibration module, a sampling rate greater than or equal to 150kHz is designated as a high-speed state, and a sampling rate less than 150kHz is designated as a low-speed state. It is stipulated that a 5.5-bit sampling result is obtained in the high-speed state, and a 6.5-bit sampling result is obtained in the low-speed state.

[0013] The beneficial effects of this invention are as follows: First, the GIC filter can reduce the influence of the filter on the sampled voltage without the need for additional DC bias, thereby reducing the impact on the DC accuracy of the entire filter module.

[0014] Furthermore, the self-calibration module can calibrate the acquisition module after warm-up and before use, greatly reducing the use of external instruments and thus lowering downtime for maintenance. The maintenance interval can be reduced from every 3 months to annually for a complete calibration of the module.

[0015] Finally, the acquisition module uses differential input and the self-calibration module uses differential output, thereby reducing the impact of common-mode noise on voltage during transmission. In traditional single-ended signal transmission, changes in the signal reference introduce noise during transmission, while differential transmission does not cause this problem. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the structure of a high-precision voltage acquisition module for SOC testing according to the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figure 1 As shown, the present invention is a high-precision voltage acquisition module for SOC testing, comprising: Signal acquisition module: The voltage to be acquired is fed into a preset programmable attenuation network, wherein the programmable attenuation network includes attenuation module A and attenuation module B, the voltage value U of the voltage to be acquired is obtained, the attenuation module is selected based on the voltage value U of the voltage to be acquired, and the voltage to be acquired through the programmable attenuation network is output in the form of a differential signal. Generate an equation U(t) representing the difference signal as a function of time t, and obtain the maximum value U of the difference signal in equation U(t). max and minimum value U min Obtain the conversion range of the ADC [V] - V + ], where V - V represents the voltage value of the smallest analog signal that the ADC can resolve. + This represents the voltage value of the largest analog signal that the ADC can resolve, based on the ADC's range [V]. - V + Select the gain factor X for the gain module; The differential signal is input to the gain module and amplified by X times before being output. The amplified differential signal is then input to the GIC filter for filtering. The filtered differential signal is then converted into a digital signal by the ADC. Self-calibration module: Generates calibration voltage based on calibration voltage generator, and outputs calibration voltage at multiples of N through digital potentiometer, where N represents the preset amplification factor; The amplified calibration voltage is filtered by the GIC filter bank and then output to the input section of the voltage acquisition through the switch array; The attenuation level D of the controller is preset, and the attenuation level D is decremented by 1 in sequence. The ADC output signal at each attenuation level is collected and compared with the digital signal in the signal acquisition module. The error coefficients, gain error and offset error of each level are calculated. The voltage obtained by subtracting the gain error and offset error from the voltage to be collected is the high-precision voltage.

[0020] It's important to note that GIC filters possess a particularly outstanding and practically valuable characteristic: they can achieve highly efficient filtering without the need for additional DC bias. Specifically, when filtering the sampled voltage, traditional filters often introduce additional DC components due to their inherent characteristics, inevitably interfering with and affecting the original sampled voltage. However, GIC filters, through their operating principle, avoid this problem. Unlike some conventional filters, they do not rely on adding additional DC bias to maintain normal operation, thus minimizing disturbances to the sampled voltage.

[0021] This interference reduction effect is directly related to the DC accuracy of the entire filter module. In practical applications, DC accuracy is one of the key indicators for evaluating filter performance, affecting the accuracy and reliability of subsequent data processing, analysis, and control. Because the GIC filter does not introduce unnecessary DC offset, the DC component of the sampled voltage maintains a high degree of authenticity and accuracy after filtering. This significantly improves the DC accuracy of the entire filter module when processing signals, effectively avoiding measurement errors and signal distortion caused by DC bias. Whether in precision measuring instruments, industrial automation control systems, or other applications with extremely high signal quality requirements, this characteristic of the GIC filter ensures that the system obtains a more accurate and stable DC signal, providing strong support for subsequent data analysis, decision-making, and equipment operation.

[0022] Furthermore, this advanced self-calibration module is highly intelligent and automated. After the system starts up and completes its warm-up process, and before the data acquisition module is officially put into use, it can automatically perform calibration. This innovative design brings many significant advantages and greatly optimizes the equipment's operation and maintenance process.

[0023] In existing technologies, to ensure the accuracy and reliability of collected data, staff frequently need to manually calibrate the acquisition module using external specialized instruments. This not only increases operational complexity but also consumes a significant amount of time and effort. Now, with the self-calibration module, the reliance on and frequency of use of external instruments are greatly reduced. The benefits of this change are particularly evident in actual operation. Previously, using the traditional method, a dedicated downtime for calibration might have been scheduled every three months, undoubtedly impacting production efficiency. However, thanks to the efficient operation of the self-calibration module, the maintenance cycle is significantly extended; only a complete calibration of the module once a year is needed to meet the system's accuracy requirements.

[0024] This improvement not only effectively reduces the risk of production interruptions caused by frequent downtime for maintenance, and improves the overall utilization rate and production efficiency of equipment, but also reduces the workload of staff, allowing them to devote more energy to other critical tasks. Furthermore, by reducing the use of external instruments, it also reduces potential risks introduced by improper human operation or instrument errors, further enhancing the stability and reliability of the entire system. In the long run, this optimization measure saves the company significant costs and enhances its competitiveness in the market.

[0025] Finally, the acquisition module employs differential input, while the corresponding self-calibration module utilizes differential output. This design combination significantly reduces the interference of common-mode noise on the voltage signal during signal transmission.

[0026] In traditional single-ended signal transmission, signals are transmitted based on a single reference point. However, real-world applications are often complex and variable, with various environmental factors easily causing this reference point to change. Once the signal reference changes, a significant amount of noise is inevitably introduced during signal transmission. This noise mixes with the useful signal, severely degrading signal quality and consequently affecting the accuracy and reliability of subsequent data processing, analysis, and control. For example, in industrial settings, numerous sources of electromagnetic interference and frequent fluctuations in environmental conditions such as temperature and humidity can destabilize the reference point of single-ended signals, exacerbating noise problems.

[0027] In stark contrast, differential transmission offers unique advantages. It transmits two signals with opposite phases and equal amplitudes simultaneously; the difference between these two signals is the quantity that truly carries the effective information. Since common-mode noise affects both signals in the same direction and at similar magnitudes, it cancels out when the two signals are subtracted to extract the effective information. In other words, even if external environmental factors cause fluctuations in the overall signal level, as long as the two differential signals are affected equally, common-mode noise will not affect the final result after differential processing.

[0028] Specifically, in the acquisition and self-calibration modules of this system, differential input ensures that the signal entering the system is accurately captured in a differential form from the outset, while differential output guarantees that the processed signal retains this anti-interference characteristic during transmission. Interference from power lines, electromagnetic radiation from space, and other forms of common-mode noise are effectively suppressed under this differential transmission mechanism. This enables the entire system to operate stably and reliably under harsh environmental conditions, providing a strong guarantee for acquiring high-precision, low-noise voltage signals. Whether in precision measurement fields, such as the detection of weak signals in laboratory instruments, or in complex industrial automation control systems for long-distance transmission of sensor signals, this design based on differential input and differential output significantly improves system performance and reliability, ensuring accurate data acquisition and processing.

[0029] In another preferred embodiment of the present invention, the method for selecting the attenuation module based on the voltage value U of the voltage to be acquired includes: A first voltage threshold U1 and a second voltage threshold U2 are preset, and 0 < U1 < U2; When the voltage value U < U1, select attenuation module A and let attenuation module A output the voltage to be collected in a direct-through manner; When U1 < U < U2, select attenuation module A to attenuate the voltage value U of the voltage to be collected by 10 times before outputting it; When U > U2, select attenuation module B to attenuate the voltage value U of the voltage to be collected by 100 times before outputting it.

[0030] It is worth noting that a signal conditioning mechanism based on automatically switching attenuation paths according to the input voltage amplitude is described. Its significance lies in achieving precise adaptation and standardized processing of a wide range of input signals by dynamically matching different ranges with corresponding attenuation coefficients. First, two key inflection point voltage values ​​are pre-set, dividing the entire possible input voltage range into three consecutive operating intervals. When the measured voltage U is detected to be in different intervals, the system automatically selects the corresponding hardware channel for processing. For small signals below the lower threshold, the attenuation module A is directly output in pass-through mode, avoiding excessive attenuation of weak signals and reducing quantization errors. When U1 < U < U2, the 10x attenuation function of the same module is activated to compress the signal amplitude. For high-amplitude signals exceeding the upper threshold, the system switches to a dedicated attenuation module B for 100x amplified attenuation. This graded attenuation strategy essentially constructs a multi-range automatic switching system, ensuring that regardless of whether the input signal is a tiny potential in the millivolt range or a high voltage close to the power rail, it can be adjusted to the optimal operating range of the analog-to-digital converter.

[0031] In another preferred embodiment of the invention, based on the ADC range [V] - V+ Methods for selecting the gain factor X of the gain module include: If the initial gain factor CX is preset and CX=1, and the constraint condition is met... Update the initial gain factor to CX+1, and repeat the above operation until the constraint is no longer met. Then set the gain factor X to the initial gain factor at the time of stopping.

[0032] Understandably, by incrementally increasing the gain level, the system automatically matches the most suitable amplification factor for input signals of different amplitudes, ensuring that the measured voltage always falls within the effective range of the ADC. Specifically, the system starts testing from the minimum gain CX=1, checking whether increasing the gain by one level causes the amplified signal to exceed the maximum measurable range of the ADC. Iteration stops when further increasing the gain would cause the signal to exceed the limit. The final selected gain factor X is the optimal solution that fully utilizes the ADC resolution without causing saturation distortion. This design achieves intelligent configuration of hardware resources, avoiding the problem of insufficient resolution for weak signals under fixed gain, and preventing nonlinear distortion caused by overload for strong signals, thus expanding the system's dynamic adaptability while ensuring measurement accuracy. This mechanism is particularly suitable for applications with large variations in input signal amplitude, automatically balancing the conflict between sensitivity and range, and improving the reliability and effectiveness of the data acquisition system.

[0033] In another preferred embodiment of the present invention, a limit voltage is preset, and when the voltage value U of the voltage to be collected is greater than the limit voltage, the subsequent steps are stopped.

[0034] It is important to note that from a hardware protection perspective, excessively high voltage can cause irreversible damage to sensitive electronic components in the system, such as breaking down semiconductor devices or burning out critical components like precision resistors. By promptly stopping subsequent steps when the voltage exceeds the limit, these potential hardware failures can be effectively avoided, extending the equipment's lifespan and reducing maintenance costs.

[0035] In another preferred embodiment of the present invention, when the filtered differential signal is converted into a digital signal by the ADC, the temperature of the entire system is kept constant.

[0036] It is important to note that maintaining a constant system temperature is crucial and requires a series of rigorous measures to ensure this process of converting the filtered differential signal into a digital signal. From a fundamental perspective, temperature changes significantly impact the performance of electronic components. For an ADC, the characteristics of its internal semiconductor devices, such as threshold voltage and carrier mobility, are closely related to temperature. Large temperature fluctuations will drastically reduce the ADC's conversion accuracy, causing the digital signal to fail to accurately reflect the original analog differential signal. Increased temperature may lower the threshold voltage, leading to increased conversion errors; conversely, excessively low temperatures may slow down the device's response speed, affecting conversion efficiency and real-time performance. Similarly, other related circuit components surrounding the ADC, including amplifiers and reference sources, will experience parameter drift due to temperature changes, thus interfering with the accuracy and stability of the entire signal conversion chain.

[0037] In another preferred embodiment of the present invention, when the calibration voltage is output as a multiple of N by means of a digital potentiometer, N ≤ X is ensured.

[0038] Understandably, from a circuit design and safety perspective, a digital potentiometer, as a programmable electronic component, has a maximum permissible operating range determined by its electrical characteristics and performance parameters. Here, X represents the maximum multiple at which the digital potentiometer can operate stably and reliably without damage or performance degradation. If N exceeds X, it may cause the internal resistance wire of the digital potentiometer to overheat, accelerating its aging process, and even potentially leading to serious malfunctions such as short circuits. This would not only cause abnormal calibration voltage output but could also cause irreversible damage to the entire circuit system. For example, under high current conditions, an excessively high multiple would cause the digital potentiometer to consume too much power, exceeding its heat dissipation capacity, thereby affecting the normal operating environment of surrounding components and reducing the reliability and stability of the entire system.

[0039] In another preferred embodiment of the present invention, if the minimum value U of the differential signal min >0, change the constraint to X×U max <V + .

[0040] In another preferred embodiment of the present invention, a sampling rate greater than or equal to 150kHz is referred to as a high-speed state, and a sampling rate less than 150kHz is referred to as a low-speed state. It is stipulated that a 5.5-bit sampling result is obtained in the high-speed state and a 6.5-bit sampling result is obtained in the low-speed state.

[0041] It is worth noting that when the system operates at high speed, i.e., a sampling rate ≥ 150kHz, a 5.5-bit sampling result is required. At high sampling rates, a large number of data points need to be processed per unit time. To ensure data processing efficiency and real-time performance, using a 5.5-bit sampling precision effectively controls the growth of data volume while maintaining a certain level of measurement accuracy. On the one hand, a higher sampling rate means the system can capture the details of signal changes more quickly, making it suitable for monitoring and analyzing signals that are sensitive to dynamic changes. On the other hand, a 5.5-bit resolution is sufficient to meet the needs of extracting basic signal features in most high-speed application scenarios, such as quality assessment of high-frequency carrier signals in the communications field and real-time feedback of fast response processes in control systems. Moreover, a relatively moderate precision setting also helps reduce the computational burden on the data processing module, improving the overall system speed and responsiveness.

[0042] Conversely, when the system operates at low speeds, i.e., a sampling rate <150kHz, it acquires 6.5-bit sampling results. Low-speed sampling typically corresponds to relatively stable, slowly changing signal environments. In such cases, increasing sampling accuracy becomes both possible and necessary. 6.5-bit high-precision sampling provides finer signal quantization, enabling the system to detect minute signal fluctuations and differences. This is crucial for applications with extremely high measurement accuracy requirements, such as precise measurement of weak physical quantities in scientific experiments and high-sensitivity detection of human physiological signals in medical devices. Increasing the sampling bit depth improves the signal-to-noise ratio and reduces quantization errors, thus more accurately reproducing the true nature of the measured signal. Simultaneously, due to the lower sampling rate, the data processing speed is relatively less demanding, allowing the system sufficient time and resources to process higher-resolution data, fully leveraging the advantages of high-precision sampling.

[0043] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A high-precision voltage acquisition module for SOC testing, characterized in that, include: Signal acquisition module: The voltage to be acquired is fed into a preset programmable attenuation network, wherein the programmable attenuation network includes attenuation module A and attenuation module B, the voltage value U of the voltage to be acquired is obtained, the attenuation module is selected based on the voltage value U of the voltage to be acquired, and the voltage to be acquired through the programmable attenuation network is output in the form of a differential signal. Generate an equation U(t) representing the difference signal as a function of time t, and obtain the maximum value U of the difference signal in the equation U(t). max and minimum value U min Obtain the conversion range of the ADC [V] - V + ], where V - V represents the voltage value of the smallest analog signal that the ADC can resolve. + This represents the voltage value of the largest analog signal that the ADC can resolve, based on the ADC's range [V]. - V + Select the gain factor X for the gain module; The differential signal is input to the gain module and amplified by X times before being output. The amplified differential signal is then input to the GIC filter for filtering. The filtered differential signal is then converted into a digital signal by the ADC. Self-calibration module: Generates calibration voltage based on calibration voltage generator, and outputs calibration voltage at multiples of N through digital potentiometer, where N represents the preset amplification factor; The amplified calibration voltage is filtered by the GIC filter bank and then output to the input section of the voltage acquisition through the switch array; The attenuation level D of the controller is preset, and the attenuation level D is decremented by 1 in sequence. The ADC output signal at each attenuation level is collected and compared with the digital signal in the signal acquisition module. The error coefficients, gain error and offset error of each level are calculated. The voltage obtained by subtracting the gain error and offset error from the voltage to be collected is the high-precision voltage.

2. The high-precision voltage acquisition module for SOC testing according to claim 1, characterized in that, In the signal acquisition module, the method for selecting the attenuation module based on the voltage value U of the voltage to be acquired includes: A first voltage threshold U1 and a second voltage threshold U2 are preset, and 0 < U1 < U2; When the voltage value U < U1, select attenuation module A and let attenuation module A output the voltage to be collected in a direct-through manner; When U1 < U < U2, select attenuation module A to attenuate the voltage value U of the voltage to be collected by 10 times before outputting it; When U > U2, select attenuation module B to attenuate the voltage value U of the voltage to be collected by 100 times before outputting it.

3. A high-precision voltage acquisition module for SOC testing according to claim 1, characterized in that, In the signal acquisition module, the range [V] of the ADC is used. - V + Methods for selecting the gain factor X of the gain module include: presetting the initial gain factor CX and CX=1, if the constraints are met. Update the initial gain factor to CX+1, and repeat the above operation until the constraint is no longer met. Then set the gain factor X to the initial gain factor at the time of stopping.

4. A high-precision voltage acquisition module for SOC testing according to claim 1, characterized in that, In the signal acquisition module, a preset limit voltage is set. When the voltage value U of the voltage to be acquired is greater than the limit voltage, the subsequent steps are stopped.

5. A high-precision voltage acquisition module for SOC testing according to claim 1, characterized in that, In the self-calibration module, when the filtered differential signal is converted into a digital signal by the ADC, the temperature of the entire system is kept constant.

6. A high-precision voltage acquisition module for SOC testing according to claim 1, characterized in that, In the self-calibration module, when the calibration voltage is output as a multiple of N using a digital potentiometer, N ≤ X is ensured.

7. A high-precision voltage acquisition module for SOC testing according to claim 1, characterized in that, In the signal acquisition module, if the minimum value U of the differential signal... min >0, change the constraint to X×U max <V + .

8. A high-precision voltage acquisition module for SOC testing according to claim 1, characterized in that, In the self-calibration module, a sampling rate greater than or equal to 150kHz is designated as a high-speed state, and a sampling rate less than 150kHz is designated as a low-speed state. It is stipulated that a 5.5-bit sampling result is obtained in the high-speed state and a 6.5-bit sampling result is obtained in the low-speed state.

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