JP2009008495A - Voltage measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a voltage measuring device capable of shortening measuring time when there are many measurement values for being average-processed so that many measuring times are required. <P>SOLUTION: Taking-in operation of storing analog voltage signals as measurement values after converting by an A/D convertor is performed predetermined times and the average values of the measurement values stored in the recording part after the taking-in operation in this voltage measuring device. This device is provided with: a comparison determining part determining whether the analog voltage signals are within the reference voltage range or not; and a computing control part storing the intermediate values of the reference voltage in the recording part and performing average-processing using the measurement values and the intermediate values when the analog voltage signals are determined to be within the reference voltage range. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, an analog voltage signal is converted by an A / D converter and stored in a storage unit as a measurement value a predetermined number of times, and an average value of the measurement values stored in the storage unit is obtained after the acquisition operation. The present invention relates to a voltage measuring device, and more particularly to a voltage measuring device capable of shortening the measurement time when there are many measurement values to be averaged, that is, when measuring many times.

  Examples of the voltage measuring device include a digital oscilloscope and a semiconductor testing device. In such an apparatus, measurement value averaging processing is performed for the purpose of removing noise components of the analog voltage signal to be measured. That is, as many measurement values as the number to be averaged are taken in, and after taking them in, the average value of the measurement values is obtained.

  Further, in the semiconductor test apparatus, it is possible to test many devices by reducing the test time of the device under test, so that the device price can be reduced. That is, the test time has a great influence on the cost of the device.

  Prior art documents related to conventional voltage measuring devices include the following.

Japanese Utility Model Publication No. 04-054461

  FIG. 4 is a block diagram showing the configuration of such a conventional voltage measuring apparatus. In FIG. 4, the A / D converter 1 converts an input analog voltage signal into digital data (measurement value). The arithmetic control unit 2 is configured by a CPU (Central Processing Unit) or the like, stores the measurement value converted by the A / D converter 1 in the storage unit 3, and uses this measurement value to calculate the voltage value of the analog voltage signal. An operation for obtaining an average value is performed. The storage unit 3 is configured by a RAM (Random Access Memory) or the like.

  An output terminal of the A / D converter 1 is connected to an input terminal of the arithmetic control unit 2, and an input / output terminal of the arithmetic control unit 2 is connected to an input / output terminal of the storage unit 3. The A / D converter 1, the calculation control unit 2 and the storage unit 3 constitute a voltage measuring device 100.

  The operation of the conventional example shown in FIG. 4 will be described. The analog voltage signal input to the A / D converter 1 is output as a measured value of digital data, and the arithmetic control unit 2 stores this measured value in the storage unit 3. This series of capturing operations is performed a predetermined number of times (average number).

  Then, after the capturing operation is completed, the calculation control unit 2 sequentially takes out the measurement values stored in the storage unit 3 and obtains an average value.

However, in the conventional example shown in FIG. 4, the acquisition time “T” of all measured values takes the time shown in Equation (1), and the acquisition time “T” of all measured values becomes longer as the average number of times increases. There was a problem of becoming.
T = one conversion time of A / D converter 1 × average number of times (1)

In particular, in a semiconductor test apparatus, if the test time (measurement time) becomes long as described above, the cost of the device increases.
Therefore, the problem to be solved by the present invention is to realize a voltage measuring device capable of shortening the measurement time when there are many measurement values to be averaged, that is, when measuring many times.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
In a voltage measuring apparatus that performs an acquisition operation for converting an analog voltage signal by an A / D converter and storing the analog voltage signal in a storage unit as a measurement value a predetermined number of times, and obtaining an average value of the measurement values stored in the storage unit after the acquisition operation. ,
A comparison / determination unit that determines whether or not the analog voltage signal is in the comparison voltage range, and an intermediate value of the comparison voltage when the analog voltage signal is determined to be in the comparison voltage range. And an arithmetic control unit that performs averaging processing using the measured value and the intermediate value.

The invention according to claim 2
The voltage measuring device according to claim 1,
The arithmetic control unit is
Of the measured values acquired by the A / D converter up to the second time, data having a large voltage value is set as the upper limit value of the comparison voltage, and data having a small voltage value is set as the lower limit value of the comparison voltage. It is characterized by.

The invention described in claim 3
In the voltage measuring device according to claim 1 or 2,
The arithmetic control unit is
When the measured value falls within the comparison voltage range, the comparison determination unit is controlled to narrow the comparison voltage range.

The invention according to claim 4
In the voltage measuring device according to any one of claims 1 to 3,
The arithmetic control unit is
When it is determined that the analog voltage signal is within the comparison voltage range, the number of measurements is counted as two.

The invention according to claim 5
In the voltage measuring device according to any one of claims 1 to 4,
The comparison determination unit
An H-side comparator and an L-side comparator to which the analog signals are input, a determination unit that performs the determination based on outputs of the H-side comparator and the L-side comparator, and the H-side by control from the arithmetic control unit And a voltage setting unit that outputs the comparison voltage of the L-side comparator.

The present invention has the following effects.
According to the first to fifth aspects of the present invention, the analog voltage signal is converted by the A / D converter and stored in the storage unit as a measurement value a predetermined number of times. After the acquisition operation, the analog voltage signal is stored in the storage unit. In the voltage measuring device for obtaining an average value of the measured values, a comparison determination unit for determining whether or not the analog voltage signal is in the comparison voltage range, and the analog voltage signal is in the comparison voltage range An arithmetic control unit that stores an intermediate value of the comparison voltage in the storage unit when determined and performs an averaging process using the measured value and the intermediate value. Since two pieces of data can be acquired, the measurement time can be shortened when there are many measurement values to be averaged, that is, when many times of measurement are performed.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a voltage measuring apparatus according to an embodiment of the present invention. Components common to those in FIG.

  In FIG. 4, the arithmetic control unit 4 is constituted by a CPU or the like, stores the measurement value converted by the A / D converter 1 in the storage unit 3, and uses this measurement value to average the voltage values of the analog voltage signal. Performs operations such as obtaining values. It also has a counter for counting the remaining number of measurements (hereinafter referred to as the remaining measurement number counter). The number of measurements is the same as the average number of measurement values.

  A high-side comparator (hereinafter referred to as an H-side comparator) 5 and a low-side comparator (hereinafter referred to as an L-side comparator) 6 compare an analog voltage signal with a comparison voltage. The determination unit 7 determines whether the analog voltage signal is in the comparison voltage range based on the outputs of the H-side comparator 5 and the L-side comparator 6. The voltage setting unit 8 outputs comparison voltages of the H-side comparator 5 and the L-side comparator 6 under the control of the arithmetic control unit 4.

  The analog voltage signal is connected to the input terminal of the A / D converter 1, the negative input terminal of the H-side comparator 5, and the positive input terminal of the L-side comparator 6. An output terminal of the A / D converter 1 is connected to one input terminal of the arithmetic control unit 4, and an input / output terminal of the arithmetic control unit 4 is connected to an input / output terminal of the storage unit 3.

  The output terminal of the arithmetic control unit 4 is connected to the input terminal of the voltage setting unit 8. One output terminal of the voltage setting unit 8 is connected to the positive side input terminal of the H side comparator 5, and the other output terminal of the voltage setting unit 8 is connected to the negative side input terminal of the L side comparator 6.

  The output terminal of the H-side comparator 5 is connected to one input terminal of the determination unit 7, and the output terminal of the L-side comparator 6 is connected to the other input terminal of the determination unit 7. The output terminal of the determination unit 7 is connected to the other input terminal of the calculation control unit 4.

  The H-side comparator 5, L-side comparator 6, determination unit 7, and voltage setting unit 8 constitute a comparison determination unit 50. The A / D converter 1, the storage unit 3, the calculation control unit 4, and the comparison / determination unit 50 constitute a voltage measuring device 101.

  The operation of the embodiment shown in FIG. 1 will be described with reference to FIGS. FIG. 2 is a flowchart showing the operation of the voltage measuring apparatus 101, and FIG. 3 is an explanatory diagram for explaining the operation of the voltage measuring apparatus 101.

  In “S001” in FIG. 2, the arithmetic control unit 4 determines whether or not the set average number is 3 or more. If the set average number is not 3 or more, “S002” in FIG. Proceed to. Also, the number of measurements is set in the remaining measurement number counter.

  Then, in “S002” in FIG. 2, the arithmetic control unit 4 performs the operation of storing the measurement value converted by the A / D converter 1 in the storage unit 3 for the average number of times (once or twice), and the average number of times If the average number of times is 1, the process ends. If the average number is 2, the average value is calculated and the process ends.

  On the other hand, in “S001” in FIG. 2, the arithmetic control unit 4 determines whether or not the set average number is 3 or more, and if the set average number is 3 or more, FIG. Proceed to middle "S003". And the operation | movement which stores the measured value converted in the A / D converter 1 in the memory | storage part 3 is performed sequentially.

  In “S003” in FIG. 2, the arithmetic control unit 4 determines whether or not the next measurement is the third time, and if the next measurement is not the third time (the first time or the second time), in FIG. Proceed to "S004". Then, in “S004” in FIG. 2, the arithmetic control unit 4 stores the measurement value converted by the A / D converter 1 in the storage unit 3.

  On the other hand, in “S003” in FIG. 2, the arithmetic control unit 4 determines whether or not the next measurement is the third time. If the next measurement is the third time, the operation proceeds to “S005” in FIG. Then, in “S005” in FIG. 2, the arithmetic control unit 4 determines whether or not the number of measurements remains, and if it remains, proceeds to “S006” in FIG. 2.

  In “S006” in FIG. 2, the arithmetic control unit 4 sets the larger voltage value of the measured values measured at the first time and the second time as the comparison voltage of the H side comparator, and sets the smaller voltage value as the L side comparator. Set to the comparison voltage. Then, the measurement is restarted, and in “S007” in FIG. 2, the arithmetic control unit 4 determines whether or not the measured value is within the range of the comparison voltage, and if it is within the range, The value of the remaining measurement number counter is decreased by “2”, and the process proceeds to “S008” in FIG.

  Specifically, when the analog voltage signal is within the comparison voltage range of the comparator, a high level voltage is output from each of the H side comparator and the L side comparator. The determination unit 7 determines whether or not the output voltages from the H-side comparator and the L-side comparator are each at a high level.

  When the output signals from the H-side comparator and the L-side comparator are each at a high level, the determination unit 7 outputs a determination signal to the calculation control unit 4. The arithmetic control unit 4 receives this determination signal and recognizes that the analog voltage signal is in the comparison voltage range.

  On the other hand, in “S007” in FIG. 2, the arithmetic control unit 4 determines whether or not the measured value is within the range of the comparison voltage. The value is decreased by “1” and the process returns to “S005” in FIG.

  In “S008” in FIG. 2, the arithmetic control unit 4 uses the intermediate value between the comparison voltage set in the H-side comparator and the comparison voltage set in the L-side comparator for the averaging process (hereinafter referred to as averaging data). Said).

  Then, in “S009” in FIG. 2, the arithmetic control unit 4 calculates an intermediate value between the comparison voltage set in the H-side comparator and the immediately preceding measurement value (hereinafter referred to as “H-side reset voltage”). Similarly, an intermediate value between the comparison voltage set in the L-side comparator and the previous measurement value (hereinafter referred to as L-side reset voltage) is calculated.

  The H-side reset voltage and the L-side reset voltage are respectively generated by the voltage setting unit 8 under the control of the arithmetic control unit 4 and output to the H-side comparator and the L-side comparator. In addition, after the process of “S009” in FIG. 2, when returning to “S005” and repeating the same process, that is, when the number of measurements remains, the H side calculated in “S009” in “S006” The reset voltage is set as a new comparison voltage for the H-side comparator, and the L-side reset voltage is set as a new comparison voltage for the L-side comparator.

  Then, in “S005” in FIG. 2, the arithmetic control unit 4 determines whether or not the number of measurements remains, and if not, the operation proceeds to “S010” in FIG. In “S010” in FIG. 2, the arithmetic control unit 4 takes out the measurement values stored in the storage unit 3 in the previous measurement and executes an averaging process. Thereby, the average value of the measured values is obtained.

  The operation will be described more specifically with reference to FIG. In FIG. 3, the horizontal axis represents time, and the time progresses as it moves to the right as viewed in the drawing. The vertical axis represents voltage, and represents the voltage of the measured value and the level of the comparison voltage set in the comparator. In FIG. 3, the average number is 7 times.

  First, when the measurement is started, the A / D converter 1 measures the first measurement value “M1” and the second measurement value “M2”. Since the voltage value of the first measurement value “M1” is larger than that of the second measurement value “M2”, the first measurement value “M1” is set as the comparison voltage “CH1” of the H-side comparator 5. Further, the second measurement value “M2” is set to the comparison voltage “CL1” of the L-side comparator 6.

  Since the third measurement value “M3” is in the comparison voltage range, that is, between “CL1” and “CH1”, the intermediate value “IM1” of the comparison voltage is used as the fourth average data. . The first to third average data are the first measurement value “M1”, the second measurement value “M2”, and the third measurement value “M3”, respectively.

  An intermediate value “CH2” between the comparison voltage “CH1” of the H-side comparator 5 and the third measurement value “M3” is set as the comparison voltage of the H-side comparator 5. Similarly, an intermediate value “CL2” between the comparison voltage “CL1” of the L-side comparator 6 and the third measurement value “M3” is set as the comparison voltage of the L-side comparator 6.

  Since the fourth measurement value “M4” is in the comparison voltage range, that is, between “CL2” and “CH2”, the intermediate value “IM2” of the comparison voltage is used as the sixth average data. . An intermediate value “CH3” between the comparison voltage “CH2” of the H-side comparator 5 and the fourth measurement value “M4” is set as the comparison voltage of the H-side comparator 5. Similarly, an intermediate value “CL3” between the comparison voltage “CL2” of the L-side comparator 6 and the fourth measurement value “M4” is set as the comparison voltage of the L-side comparator 6.

  Although the fifth measurement value “M5” is the seventh average data, it is not used for the comparison voltage correction of the comparator because it is not within the comparison voltage range, that is, between “CL3” and “CH3”. . Therefore, the comparison voltage of the H-side comparator 5 remains “CH2” and the comparison voltage of the L-side comparator 6 remains “CL2”.

Here, since seven pieces of average data have been acquired, the measurement is completed. The arithmetic control unit 4 takes out the data for averaging stored in the storage unit 3 and obtains the average value. Specifically, the average value AV is obtained by executing the calculation shown in the equation (2).
Average value AV = (M1 + M2 + M3 + IM1 + M4 + IM2 + M5) / 7 (2)

  Conventionally, seven times of measurement are required to obtain seven pieces of average data, but in the present invention, five times of measurement are sufficient. In the example of FIG. 3, the average number of times is as small as 7, so there is not much difference between the measurement time and the conventional example. However, for example, when the average number is 100 times, the minimum number of measurements is 51 (the third time). In the subsequent measurement, assuming that two data for averaging can be acquired in one measurement), the measurement time is about ½ compared with the conventional measurement.

  As a result, when the A / D converter 1 acquires the measurement value and the analog voltage signal is included in the comparison voltage range using the H-side comparator 5 and the L-side comparator 6, the intermediate value of the comparison voltage is also the average data. By doing so, two pieces of data for averaging can be acquired in one measurement. Therefore, when there are a large number of measurement values to be averaged, that is, when measuring many times, the measurement time can be shortened.

  In the embodiment shown in FIGS. 1 to 3, when the measured value is in the comparison voltage range, the comparison voltage range is narrowed to perform the next measurement. However, this is not always necessary. When the voltage measurement accuracy is not required, or when the noise of the analog voltage signal to be measured is low, the comparison voltage range may be fixed.

  In the embodiment shown in FIGS. 1 to 3, when a measured value is included in the comparison voltage range, an intermediate value between the comparison voltage of the comparator and the previous measured value is set as a new comparison voltage value. Is not required to be a new comparison voltage value, and the rate of narrowing the comparison voltage range is not particularly limited.

1 is a configuration block diagram showing an embodiment of a voltage measuring apparatus according to the present invention. It is a flowchart which shows operation | movement of a voltage measuring device. It is explanatory drawing explaining operation | movement of a voltage measuring device. It is a block diagram showing a conventional voltage measuring device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 A / D converter 2, 4 Arithmetic control part 3 Memory | storage part 5 H side comparator 6 L side comparator 7 Judgment part 8 Voltage setting part 50 Comparison judgment part 100,101 Voltage measuring apparatus

Claims (5)

In a voltage measuring apparatus that performs an acquisition operation for converting an analog voltage signal by an A / D converter and storing the analog voltage signal in a storage unit as a measurement value a predetermined number of times, and obtaining an average value of the measurement values stored in the storage unit after the acquisition operation. ,
A comparison determination unit for determining whether or not the analog voltage signal is in a comparison voltage range;
Arithmetic control for storing an intermediate value of the comparison voltage in the storage unit when the analog voltage signal is determined to be in the comparison voltage range, and performing an averaging process using the measured value and the intermediate value And a voltage measuring device. The arithmetic control unit is
Of the measured values acquired by the A / D converter up to the second time, data having a large voltage value is set as the upper limit value of the comparison voltage, and data having a small voltage value is set as the lower limit value of the comparison voltage. The voltage measuring device according to claim 1. The arithmetic control unit is
3. The voltage measuring device according to claim 1, wherein when the measured value is in the comparison voltage range, the comparison determination unit is controlled to narrow the comparison voltage range. 4. The arithmetic control unit is
4. The voltage measuring device according to claim 1, wherein when the analog voltage signal is determined to be within the comparison voltage range, the number of measurements is counted as two times. 5. The comparison determination unit
An H-side comparator and an L-side comparator to which the analog signals are respectively input;
A determination unit that performs the determination based on outputs of the H-side comparator and the L-side comparator;
The voltage setting part which outputs the said comparison voltage of the said H side comparator and the said L side comparator by control from the said arithmetic control part is comprised, The one in any one of Claims 1-4 characterized by the above-mentioned. Voltage measuring device.

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