Analog voltage high-precision measurement method and system

Abstract

The invention discloses an analog voltage high-precision measurement method and system, and belongs to the technical field of electronic measurement, and the analog voltage high-precision measurement method comprises the following steps: (1) taking a preset interval as a search interval; (2) continuously distributed N reference voltage intervals are divided in the search interval, the N reference voltage intervals are adopted to compare the input voltage at the same time, a result interval of the input voltage is obtained, the result interval is one of the N reference voltage intervals, and N is a preset integer larger than 1; (3) if the width of the current result interval is smaller than or equal to the voltage value corresponding to the least significant bit of the single DAC, entering the step (4); otherwise, taking the current result interval as a search interval, and then returning to the step (2); and (4) taking the median voltage of the current result interval as the measurement result Vmeasure of this round, and recording the measurement result Vmeasure. According to the invention, high-precision measurement approaching the theoretical limit can be realized at a configurable speed, and the fluctuation characteristics of the voltage can be synchronously obtained.

Description

Technical Field

[0001] This invention belongs to the field of electronic measurement technology, specifically relating to a high-precision, fast digital measurement system and method for analog voltage, which is particularly suitable for applications that are space-sensitive and require high-precision voltage ripple and dynamic characteristic analysis. Background Technology

[0002] In fields such as integrated circuit testing, power quality monitoring, and precision sensor reading, high-precision measurement of analog voltage is a fundamental requirement. Traditional measurement methods mainly rely on benchtop oscilloscopes or handheld digital multimeters. However, oscilloscopes are bulky and inconvenient, and their vertical resolution is usually limited; while handheld multimeters, although portable, have low sampling rates and cannot capture and analyze the dynamic characteristics of voltage ripple and transient fluctuations, and their accuracy is difficult to guarantee below the microvolt level. Existing solutions based on monolithic integrated analog-to-digital converters (ADCs) often face a trade-off between conversion speed, power consumption, and cost when pursuing high resolution (such as 20 bits or more), and their fixed conversion architecture makes it difficult to flexibly configure speed and accuracy. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a measurement and calculation method that combines high precision, high flexibility, relatively simple structure and easy analysis of voltage dynamic characteristics.

[0004] The technical solution adopted by the present invention to solve the aforementioned technical problem is a high-precision analog voltage measurement method, characterized by comprising the following steps:

[0005] (1) Use a preset interval as the search interval;

[0006] (2) Divide the search interval into N consecutively distributed reference voltage intervals, and use the N reference voltage intervals to compare the input voltage simultaneously to obtain the result interval of the input voltage. The result interval is one of the N reference voltage intervals, where N is a preset integer greater than 1.

[0007] (3) If the width of the current result interval is less than or equal to the voltage value corresponding to the least significant bit of a single DAC, proceed to step (4); otherwise, use the current result interval as the search interval and return to step (2).

[0008] (4) Take the median voltage of the current result interval as the measurement result V_measured for this round and record it.

[0009] Furthermore, it also includes step (5): after waiting for the predetermined time, return to step (2).

[0010] In step (2), the N reference voltage ranges are uniformly distributed.

[0011] The present invention also provides a high-precision analog voltage measurement system employing the aforementioned high-precision analog voltage measurement method, characterized in that it includes a processing unit and N parallel measurement branches, each measurement branch being connected to the processing unit; each measurement branch includes a voltage comparator and a DAC unit, the first input terminal of the voltage comparator serving as the input terminal of the voltage to be measured, the second input terminal being connected to the output terminal of the DAC unit, the input terminal of the DAC unit being connected to the processor unit, and the output terminal of the voltage comparator being connected to the processor unit.

[0012] It also includes a storage unit connected to the processing unit for storing the measurement results of each round.

[0013] This invention provides a high-precision analog voltage measurement system and method based on the principle of parallel successive approximation. Through a unique parallel comparison and iterative convergence mechanism, it can achieve high-precision measurement close to the theoretical limit at a configurable speed and simultaneously acquire the voltage fluctuation characteristics.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] High precision: By selecting a high-resolution DAC and a high-precision reference source, the system has extremely low background noise and quantization error. Combined with the iterative convergence mechanism, the final measurement accuracy can approach the theoretical resolution limit of the DAC.

[0016] High speed and flexibility: By using multiple comparators working in parallel, the search range can be significantly narrowed in a single comparison, resulting in a substantial improvement in convergence speed compared to the traditional binary search method's successive approximation. Measurement speed (number of iterations) and accuracy can be flexibly configured via software.

[0017] Dynamic analysis capability: It can not only output high-precision single measurement values, but also provide the time-domain fluctuation characteristics of voltage signals through continuous sampling, thus partially realizing the analysis function of an oscilloscope.

[0018] Simple structure: The core of the system consists of standardized digital and analog chips, eliminating the need for complex analog front-end conditioning circuits or dedicated high-speed, high-precision ADC chips, thus reducing the complexity of hardware design and procurement. Attached Figure Description

[0019] Figure 1 This is a block diagram of the measurement system provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the voltage range during the iterative convergence process in the measurement method provided in this embodiment of the invention.

[0021] Figure 3 A flowchart of the measurement method provided in an embodiment of the present invention. Detailed Implementation

[0022] See Figures 1-3 The high-precision analog voltage measurement system of the present invention includes:

[0023] The microcontroller unit (MCU) serves as the core of the system's control and computation.

[0024] N high-precision voltage comparators, where N is an integer greater than or equal to 2;

[0025] N high-precision digital-to-analog converters (DACs) correspond one-to-one with the N comparators;

[0026] A high-precision reference voltage source;

[0027] The system is connected as follows: the output of the high-precision reference voltage source is connected to the voltage reference input of all N DACs; the analog voltage output of each DAC is connected to the inverting input of a corresponding comparator; the non-inverting inputs of all N comparators are connected in parallel and are connected to the analog voltage signal being measured; the digital outputs of all N comparators are connected to the input ports of the MCU; and the MCU controls the output voltage values ​​of all N DACs through a digital interface.

[0028] The high-precision analog voltage measurement method of the present invention includes the following steps:

[0029] Step S1: System initialization and range setting. The MCU sets the initial voltage upper limit V_high and lower limit V_low based on the estimated range of the measured voltage.

[0030] Step S2: Parallel Comparison and Coarse Range Localization. The MCU controls N DACs to output N reference voltages evenly distributed within the range [V_low, V_high], while simultaneously reading the output states of the N comparators. Based on the comparison results, the measured voltage is locked between two adjacent reference voltages, and the search range is updated to [V_low_new, V_high_new].

[0031] Step S3: Iterative convergence and fine measurement. Using the new search interval obtained in step S2 as the current global search interval, repeat the parallel comparison process of step S2 to further narrow down the interval where the measured voltage is located.

[0032] Step S4: Result Determination and Output. Repeat step S3 until the width of the search interval is less than or equal to the voltage value corresponding to the least significant bit (LSB) of a single DAC. Take the median voltage of the current search interval as the final measurement result V_measured.

[0033] Optional step S5: Dynamic characteristic analysis. In continuous measurement mode, the MCU repeats steps S1 to S4 at fixed time intervals to obtain the voltage sequence V_measured(t), and performs statistical analysis on the sequence to obtain the average value, RMS value, peak-to-peak value, ripple coefficient, and fluctuation frequency characteristics of the measured voltage.

[0034] Example

[0035] To make the technical solution of this invention clearer and easier to understand, the complete implementation process of this invention is described in detail below with reference to specific embodiments (taking N=4 16-bit DACs and a high-precision reference source of 5.0V as an example):

[0036] Implementation prerequisites: Prepare a microcontroller (such as the STM32 series), four high-precision comparators with input offset voltages in the range of ±5μV, four DACs with a resolution of 16 bits or higher (such as the AD5664), and a 5V reference voltage source with an initial accuracy better than ±0.1% (such as the REF5050). Build the hardware circuit according to the system connection relationship.

[0037] Single high-precision measurement implementation steps:

[0038] 1. Range setting: Estimate the voltage to be measured to be between 0-5V, and set V_low=0V and V_high=5V.

[0039] 2. First Parallel Comparison: The MCU controls four DACs to output reference voltages of 1V, 2V, 3V, and 4V respectively (i.e., uniformly distributed). The outputs of the four comparators are read. Assuming the comparator results from low to high correspond to [0, 0, 1, 1] for the DACs, this indicates that the measured voltage is between 2V and 3V. The search interval is updated to V_low_new=2V, V_high_new=3V.

[0040] 3. Iterative Convergence: Within the new interval [2V, 3V], control the DAC output again to 2.2V, 2.4V, 2.6V, 2.8V. Read the comparison results and further narrow down the interval. Repeat this process.

[0041] 4. Output Results: The iteration stops when the interval width is less than the voltage value corresponding to one LSB of the DAC (approximately 76μV for a 16-bit DAC at a 5V range). The median value of the current interval is taken as the measurement result V_measured.

[0042] Dynamic characteristic analysis:

[0043] 1. Set the MCU timer to trigger the complete measurement process described in 6.2 every 10ms for 1 second to obtain 100 high-precision voltage data points V_measured(t).

[0044] 2. The MCU performs software analysis on this data sequence to calculate the average value, effective value, peak-to-peak value (maximum value - minimum value), ripple coefficient (peak-to-peak value / average value) of the voltage within this 1 second, and can perform simple frequency domain analysis to determine the main fluctuation frequency.

[0045] The number of parallel comparators N (within the hardware's capabilities), the termination conditions for iterative convergence (such as interval width or a fixed number of iterations), and the time interval for continuous sampling can be easily adjusted via software to adapt to measurement scenarios with different requirements for accuracy, speed, and dynamic analysis.

Claims

1. A high-precision analog voltage measurement method, characterized in that, Includes the following steps: (1) Use a preset interval as the search interval; (2) Divide the search interval into N consecutively distributed reference voltage intervals, and use the N reference voltage intervals to compare the input voltage simultaneously to obtain the result interval of the input voltage. The result interval is one of the N reference voltage intervals, where N is a preset integer greater than 1. (3) If the width of the current result interval is less than or equal to the voltage value corresponding to the least significant bit of a single DAC, proceed to step (4); otherwise, use the current result interval as the search interval and return to step (2). (4) Take the median voltage of the current result interval as the measurement result V_measured for this round and record it.

2. The high-precision analog voltage measurement method as described in claim 1, characterized in that, It also includes step (5): After waiting for the scheduled time, return to step (1).

3. The high-precision analog voltage measurement method as described in claim 1, characterized in that, In step (2), the N reference voltage ranges are uniformly distributed.

4. A high-precision analog voltage measurement system employing the high-precision analog voltage measurement method according to claim 1, characterized in that, It includes a processing unit and N parallel measurement branches, each measurement branch being connected to the processing unit; each measurement branch includes a voltage comparator and a DAC unit, the first input terminal of the voltage comparator is used as the input terminal of the voltage to be measured, the second input terminal is connected to the output terminal of the DAC unit, the input terminal of the DAC unit is connected to the processor unit, and the output terminal of the voltage comparator is connected to the processor unit.

5. The high-precision analog voltage measurement system as described in claim 4, characterized in that, It also includes a storage unit connected to the processing unit for storing the measurement results of each round.

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