JP2010056587A - D/a conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a D/A conversion device capable of setting an output voltage with high resolution by a plurality of D/A conversion devices having low resolution. <P>SOLUTION: The D/A conversion device includes the plurality of D/A conversion devices to which respective different output voltage ranges have been set, and a computing unit for adding or subtracting the output voltages of the D/A conversion devices. Also, the D/A conversion device includes the plurality of D/A conversion devices to which respective different output voltage ranges have been set, and a computing unit that has the output voltages of the D/A conversion devices input via an amplifier and adds or subtracts them. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a DA converter, and more particularly to a DA converter that can output a conversion voltage with high resolution.

  FIG. 5 is a configuration diagram illustrating an example of a conventional DA converter that is incorporated and used in various electronic devices. This DA converter is composed of a control device 1, a DA converter 2, an amplifier 3, and a control object 4. The control device 1 sets a predetermined voltage corresponding to the resolution within the voltage output range of the DA converter 2 in the DA converter 2. The bit width of the digital signal input to the DA converter 2 is controlled to a predetermined width. The amplifier 3 amplifies the voltage converted and output from the DA converter 2 so as to satisfy the voltage range required by the control target 4 and supplies the amplified voltage to the control target 4.

  For example, if the voltage range required by the control object 4 is 0 to 10 V, the output voltage range of the DA converter 2 is 0 to 5 V, and the bit width of the DA converter 2 is set to 3 bits by the control device 1, The DA converter 2 sets an output voltage of 0 to 5 V, and the amplifier 3 amplifies the difference from 6 to 10 V, which is the required range of the output voltage required by the control target 4.

  FIG. 6 is an explanatory diagram showing an example of the output range Out for the required range Re using the conventional 3-bit DA converter 2. FIG. 6A shows the output required range Re and the set target T, and FIG. The output range Out of the bit DA converter 2 and the set output voltage E are shown. As shown in (b), the settable output voltage of the DA converter 2 is only the voltage at the position of the scale line corresponding to the set resolution. That is, the control device 1 outputs the setting data to the DA converter 2 so that the setting output voltage E is as close as possible to the setting target T, and obtains a desired setting value as the output voltage of the amplifier 3.

  FIG. 7 is a diagram showing an example of the output range Outa with respect to the required range Re using the conventional 4-bit DA converter 2, where (a) shows the output required range Re and the set target T, and (b) shows 3 The output range Out of the bit DA converter 2 and the set output voltage Ea are shown. As shown in FIG. 7, the difference between the set output voltage Ea and the set target T can be made smaller than that in FIG. 6 by using a DA converter 2 having a higher resolution than that in FIG.

  Patent Document 1 uses a low-resolution / low-speed DA converter to achieve a high-resolution / high-speed DA converter by using a circuit configuration in which an integrator provided for each channel is shared. The circuit scale is reduced and the cost is reduced.

JP-A-8-228153

  However, there is a problem that the cost increases when the high-resolution DA converter 2 is used.

  The present invention solves these problems, and an object of the present invention is to provide a DA converter capable of setting an output voltage with high resolution by using a plurality of low-resolution DA converters.

In order to achieve the above object, claim 1 of the present invention provides:
A plurality of DA converters each having a different output voltage range;
An arithmetic unit for adding or subtracting the output voltage of these DA converters,
And a DA converter characterized by comprising:

Claim 2
A plurality of DA converters each having a different output voltage range;
An arithmetic unit that inputs or subtracts the output voltage of these DA converters through an amplifier,
And a DA converter characterized by comprising:

Claim 3 is the DA converter according to claim 1 or 2,
Among the plurality of DA converters, the output voltage range of the first DA converter is set to satisfy the output voltage range required for the DA converter, and the output voltage range of the second DA converter is the first DA converter. It is set to satisfy the resolution of the output voltage of the converter.

  With this configuration, the output voltage can be set with a high resolution using a plurality of conventional DA converters with a low resolution, and the cost can be reduced by substituting the DA converter with a high resolution with a plurality of DA converters with a low resolution. I can plan.

  The DA converter according to the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram illustrating an embodiment of the present invention, which includes a control device 10, DA converters 20A and 20B, a computing unit 30, and a control target 40.

  In such a configuration, the control device 10 sets desired voltages to the DA converters 20A and 20B, respectively. The computing unit 30 adds or subtracts the output voltages of the DA converters 20A and 20B and supplies the result to the control target 40.

  For example, the control device 10 controls the output range of one DA converter 20A to be OutA, and controls the output range of the other DA converter 20B to be OutB. As a result, the output range OutC of the computing unit 30 becomes OutC = OutA + OutB.

  FIG. 2 is a diagram for explaining the operation of FIG. 1, and shows an example in which DA converters 20A and 20B each having a resolution of 3 bits are used. 2A shows an output request range Re requested from the control target 40 and a set target T that is arbitrarily set, and FIG. 2B shows an output range OutA and a set output voltage EA of one DA converter 20A. (C) shows the output range OutB and set output voltage EB of the other DA converter 20B, and (d) shows the output range OutC and set output voltage EC of the computing unit 30.

  Specifically, the output range OutA of one DA converter 20A is set to be equal to the output request range Re, and the output request range Re is divided into eight. The output range OutB of the other DA converter 20B is set to be equal to the one scale width of the output range OutA of the one DA converter 20A, and the one scale width of the output range OutA is divided into eight.

  With this configuration, after roughly setting the set target T with a resolution of 1/8 with the set output voltage EA of one DA converter 20A, the set output voltage EB of the other DA converter 20B is set. Can be used for fine adjustment with a resolution of 1/64. By adding the set output voltages EA and EB by the computing unit 30, the voltage EC input to the control target 40 can be arbitrarily set with a high resolution of 1/64 within the output range OutC. The resolution of 1/64 corresponds to the resolution that can be obtained when a 6-bit DA converter is used.

  Note that the arbitrary voltage output range OutB of the DA converter 20B may be equal to or greater than one graduation width of the arbitrary voltage output range OutA of the DA converter 20A.

  Thus, by using a plurality of low-resolution DA converters, the output voltage can be set with high resolution, and by replacing the high-resolution DA converters conventionally used with the low-resolution DA converters 20A and 20B, Cost can be reduced.

  Furthermore, since a high resolution can be realized, the set output voltage EC input to the control object 40 can be set to a higher resolution than before. That is, by setting the set value for the set target T in two stages of coarse and fine, the same effect as using a DA converter with a higher resolution than in the past can be obtained.

  In the embodiment of FIG. 1, the case where the two DA converters 20A and 20B are used has been described, but the number of DA converters may be three or more.

  FIG. 3 is a block diagram showing another embodiment of the present invention, and the same reference numerals are given to portions common to FIG. In the embodiment of FIG. 3, the output signal of one DA converter 20A is input to one input terminal of an arithmetic unit 30 via an amplifier 50A, and the output signal of the other DA converter 20B is input to the arithmetic unit 30 via an amplifier 50B. To the other input terminal.

  In such a configuration, the amplifier 50A is adjusted so that its output voltage becomes a value in the output range OutA of any voltage, and the amplifier 50B is adjusted so that its output voltage becomes a value in the output range OutB of any voltage. .

  FIG. 4 is a flowchart for explaining the operation flow of the embodiment shown in FIG. First, the control device 10 sets a set target T (step SP1), inputs the set target T to the set value EA calculation unit, and inputs it to the difference (T-EA) calculation unit. The set value EA calculation unit calculates the set output voltage EA (step SP2) and inputs the set output voltage EA to the DA converter 20A and the difference (T-EA) calculation unit. The DA converter 20A outputs the analog conversion voltage of the set value EA to one input terminal of the arithmetic unit 30 via the amplifier 50A (step SP3).

  Next, the difference (T-EA) calculation unit calculates the difference between the set target T and the set output voltage EA (step SP4), and inputs the calculation result to the set value EB calculation unit. The set value EB calculator calculates the set output voltage EB (step SP5) and inputs it to the DA converter 20B. The DA converter 20B outputs the analog conversion voltage of the set value EB to the other input terminal of the arithmetic unit 30 via the amplifier 50B (step SP6). The calculator 30 calculates EC = EA + EB (step SP7), and outputs the calculation result to the control target 40 (step SP8).

  The computing unit 30 may be an adder or a subtracter.

  Furthermore, by using the configuration of the DA converter of the present invention, a DA converter having a resolution not commercially available can be realized.

  As described above, according to the present invention, an output voltage can be set with a high resolution by using a plurality of conventional low resolution DA converters, and a high resolution DA converter can be replaced with a plurality of low resolution DA converters. Thus, a DA converter capable of reducing the cost can be realized, and the practical effect is great as a DA converter incorporated in various electronic devices.

It is a block diagram which shows one Example of this invention. It is operation | movement explanatory drawing of FIG. It is a block diagram which shows the other Example of this invention. It is a flowchart explaining the flow of operation | movement of the Example shown in FIG. It is a block diagram which shows an example of the conventional DA converter. It is a figure which shows an example of the output range with respect to the request | requirement range using the conventional 3 bit DA converter 2. FIG. It is a figure which shows an example of the output range with respect to the request | requirement range using the conventional 4-bit DA converter 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control apparatus 20 DA converter 30 Calculator 40 Control object 50 Amplifier

Claims (3)

A plurality of DA converters each having a different output voltage range;
An arithmetic unit for adding or subtracting the output voltage of these DA converters,
A DA converter characterized by comprising: A plurality of DA converters each having a different output voltage range;
An arithmetic unit that inputs or subtracts the output voltage of these DA converters through an amplifier,
A DA converter characterized by comprising:   Among the plurality of DA converters, the output voltage range of the first DA converter is set to satisfy the output voltage range required for the DA converter, and the output voltage range of the second DA converter is the first DA converter. 3. The DA converter according to claim 1, wherein the DA converter is set so as to satisfy a resolution of an output voltage of the converter.

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