JPS60204122A - Digital-analog converting circuit - Google Patents

Abstract

PURPOSE:To attain the standardization of a board by applying an external reference voltage required for a D/A converter externally from the board to increase the degree of freedom of the reference voltage applied to the converter. CONSTITUTION:The D/A converting circuit 4 is mounted on the board 1 and a digital signal from a device 2 such as a microcomputer is inputted to a digital input terminal 3 of the converting circut 4. An output from an analog output terminal 5 of the converting circuit 4 is outputted to analog signal output terminal 6 of the board 1. Further, a reference voltage input external terminal 10 of the board 1 is connected to a reference voltage input terminal 7 of the converting circuit 4 and the reference voltage from a reference voltage source 8 is fed to the external terminal 10 from a reference voltage selecting terminal 9. Then the reference voltage applied to the converting circuit 4 is fed from the outside of the board 1 to increase the degree of freedom of the reference voltage applied to the converting circuit 4 thereby attaining the standardization of the board 1.

Description

[Detailed description of the invention] [Technical field of invention] This invention is a D/A conversion circuit (Digital t.

The present invention relates to analog conversion circuits), and particularly relates to improvements in processing for supplying necessary reference voltages to the circuits.

[Prior art]

As a conventional D/A conversion circuit of this type, the one shown in FIG. 1 is known. In the figure, code (1) is a board on which a D/A conversion circuit (4) is mounted, (2) is a device that outputs digital signals such as a microcomputer, and (3)
is a D/A that inputs the digital signal from the above device (2).
Digital signal input terminal of conversion circuit (4), (5) is D/
This is an analog signal output terminal of the A conversion circuit (4), and the D
The analog signal input to the /A conversion circuit is converted into a digital signal and output. (6) is an analog signal output external terminal connected to the analog signal output terminal, and (7) is a reference voltage input terminal for inputting the reference voltage necessary for the D/A conversion circuit (4), as shown in the figure. It is connected to the reference voltage #(8) in the same board rII via the reference voltage selection terminal (9). Further, a conductor pattern on the substrate C1l is connected between the reference voltage source (8) and the reference voltage selection terminal (9).
The reference voltage to be applied to the reference voltage selection terminal is selected by changing signal connections using lead wires or the like.

Next, the operation of the D/A conversion circuit explained with reference to FIG. 1 above will be explained. In FIG. 1, there are six digital signal input terminals (3), and a voltage of 8V is applied to the reference voltage input terminal (7).

A digital signal corresponding to the controlled object is input to the digital signal input terminal (? +
Enter +. The input digital signal is 1 or 0
The level signal is 6 bits (t), (000)z=0,
(001)2=1, (010)+=2, (011)2=
3, (100)2=4, (101)2=5, (110)
2=6, (111)i=7, and so on, which are sent to the D/A conversion circuit (4) as eight signals p. Same board (11
The reference voltage output from the reference voltage source (8) is input to the reference voltage input terminal (manually input to the digital signal), and the input reference voltage is input to the D/A conversion circuit (4). D
/A After conversion, the analog signal becomes 0/8.1/8
．． 2/8.3/8.4/8.5/8.6/8.7/8V
This signal is output to the analog signal output terminal (5), and this signal is output to the analog signal output external terminal (6) and output to the outside of the board full.

When changing the output 1ZJJ of the above D/A conversion circuit (4), input the reference voltage input from the reference oil and pressure selection terminal (9) on the same board (1) to the reference voltage input terminal (F). It is sufficient to change the reference voltage, and in order to change the reference voltage, the reference phase is changed using a connection switch, a lead wire, a pattern wire, etc. between the voltage selection terminal (9) and the reference voltage source (8). .

Note that the number of digital input terminals (3) mentioned above is not limited to six, but can be as many as necessary, and the reference voltage is also 8V.
Any kind of candy can be used as needed.

Since the reference Ichikawa required for the conventional D/A conversion circuit (4) is configured to be supplied as described above, depending on the controlled object! l) When changing the output range of the D/A converter circuit (4), the reference box and pressure '? ffl”
In order to change the switch, within the same board (1),
It is necessary to change the connections of lead wires, pattern wires, etc. Therefore, it is difficult to standardize the board (1), and the range of variation within one board is limited, so it is difficult to standardize the board (1). Since the selection and change of voltage cannot be changed externally, there are drawbacks such as the need to change the design of the board (11).

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones, and the external reference pressure required for the D/A conversion circuit is supplied from outside the board instead of within the same board, and thereby, The present invention provides a D/A converter circuit which increases the degree of freedom in the reference voltage applied to the D/A converter circuit and allows standardization of the substrate.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. Second
In the figure, the symbol (Fl) is a board on which a D/A conversion circuit (4) is mounted, (2) is a device that outputs a digital signal such as a microcomputer, and (3) is the above device Hg (2
) D/A conversion circuit (4) that inputs the digital signal from
The digital signal input terminal (5) is the D/A conversion circuit (
At the analog signal output terminal 4), the analog signal input to the #D/A conversion circuit is converted into a digital signal and output. (6) is an analog signal output external terminal connected to the analog signal output terminal, and (7) is a reference voltage input terminal for inputting the reference voltage necessary for the D/A conversion circuit (4). are the same as those shown with the same reference numerals in FIG. 1 described above.

The above reference voltage input terminal (7) is connected to the reference voltage input external terminal 00) as shown in the figure, and the reference voltage input external terminal is connected to the reference voltage source (8) outside the board ffl. 9).

It should be noted that the number of digital signal input terminals (3) input to the D/A conversion circuit (4) in FIG. 2 is not limited to six, but can be as many as necessary.

Next, the operation of the D/A conversion Oki 1 route explained with reference to FIG. 2 above will be explained. In Figure 2, there are three digital signal input terminals (3), and a reference voltage input terminal (7).
A voltage of 8V is applied to.

A digital signal input terminal (3) receives a digital signal corresponding to one controlled object from a device (2) that outputs a digital signal such as a microcomputer to the D/A conversion circuit (4).
Enter. The input digital signal is a 0-level signal that spans 6 bits (1'), (000)2=0, (
001)2=1, (010)2=2, (011)2=3
, (100)2 = 4, (101)2 = 5, (110)
The signal is given to the D/A conversion circuit (4) as eight signals such as 2=6 and (111)2=7. The above board (1
The reference voltage input from the external reference voltage source (8) of 1 to the pressure input external terminal (10) is input to the reference voltage selection terminal (force), and the voltage input by the digital signal is The reference voltage is D/A converted by the D/A conversion circuit (4), and the analog signal is 0/8.1/8.2/8.6/
8.4/8.5/8.6/8.7/8 V is output to the analog signal output terminal (5), this signal is output to the analog signal output external terminal (6), and the signal is output to the board ( 1
) is output to the outside.

When changing the output range of the above D/A conversion circuit (a), connect the reference voltage input terminal (7) to the reference voltage input external terminal (
10), the reference voltage output from the reference voltage selection terminal (9) is changed from the substrate rJl outer layer. This standard/r
To change the 1i pressure, connect the reference voltage selection terminal (9) and the reference voltage. l￥ EE # (Change the connection to 81 using a switch, lead wire, pattern wire, etc.)

Furthermore, the number of digital input terminals (3) is not limited to 6, and any number of terminals can be used as needed, and the reference pressure is not limited to 87, but any number can be used as necessary. The name i11 is also iJJ's death.

In the above embodiment, the reference yi (1 + reference 4 pressure is input directly from the outside to the D/A conversion circuit (4)), but as shown in Fig. 6, the same board (1 ) is standard 1 (
1 voltage output (81 is mounted, the output πJ is sent out from the reference voltage output external S terminal U to the external board (11), and this heavy pressure is externally connected to other 1L other circuits, etc. Apply appropriate partial pressure, amplification, etc. internally to the carp, and then apply the resulting quasi-voltage to the external terminal (1).
2, and the reference 4. of the D/A conversion circuit (4). It can also be input to the pressure input terminal (7).

In addition, in the above explanation, we have explained the case where a simple signal is simply input to the reference voltage and piezo input terminal (7), but when the reference voltage and the piezo input terminal are input to the reference voltage and the piezo input terminal, a sine wave-like signal that changes every moment with time (No. 8 may be input, and in this case, the same effect as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, in a D/A conversion circuit that converts a digital signal into an analog signal, the external reference voltage required for D/A conversion is
) is mounted on the board (external reference voltage input terminal f7) is provided on the # board so that it can be received from a board other than 17, and the external reference τi pressure is input to the above D/ Since the external reference voltage of the D/A conversion circuit can be arbitrarily selected without changing the substrate 11), the D/A conversion circuit can be applied by changing the reference voltage. Even when changing the output range of the conversion circuit, there is no need to change the base & Effects such as this can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a circuit board and the like constituting a conventional D/A conversion circuit, and FIG. 2 is a D/A conversion circuit showing an embodiment of the present invention.
A. Schematic configuration diagram of a conversion circuit board, etc. FIG. 6 is a schematic configuration diagram showing another embodiment of the present invention. (1): Board, (41: D/A conversion circuit, (7): Reference voltage input terminal, (81: Reference voltage source, (91: Reference voltage selection terminal, 0[: Reference voltage input external terminal 5) The same reference numerals in each figure indicate the same or similar parts. Agent Patent Attorney Mitsuro Kimura Figure 1 Figure 2 WE3 Figure 3 Procedural Amendment (Voluntary) July 30, 1980 Commissioner of the Patent Office 1 General 1; Indication of the case Japanese Patent Application No. 59-59605 2, Name of the invention D/A conversion circuit: 3. Part 4 to the person making the amendment Representative Kata Yuhito 4, Agent 5, Target of Masaru Kyo-sode 6, Contents of the amendment ( 1) Correct "analog signal to digital signal" on page 2, lines 9-10 of Specification A to "digital signal to analog signal". (2) Correct "digital signal to analog signal" on page 5, line 19 of the specification. The analog signal is a digital signal, and the digital signal is an analog signal.

Claims (1)

[Claims] In a D/A conversion circuit that converts digital signals to analog signals, the external reference voltage required for D/A conversion is
An external reference voltage input terminal is provided on the board so that it can be received from a board other than the board on which the /A conversion circuit is mounted, and the external reference voltage is input to the D/A conversion circuit through the external reference voltage input terminal.
The voltage is applied to the A conversion circuit, thereby causing the above/
A D/A characterized in that the external reference voltage of the A conversion circuit can be arbitrarily selected without changing the board.
conversion circuit.