JPH0468820A - D/a converter - Google Patents

Abstract

PURPOSE:To execute a high-resolution D/A conversion processing without increasing cost by dividing an inputted digital signal into high-order and low-order digital signals, respectively latching these divided digital signals and executing the D/A conversion processing. CONSTITUTION:For a reference voltage VR at a four bit D/A converter 103, a Vref is selected by an analog switch 104 according to a high-order selective signal, and the D/A conversion processing is executed to the high-order digital signal outputted from the gate of a four bit-latch circuit 101. After the D/A conversion processing by the four bit D/A converter 103, an analog signal is inputted to a high-order VOUT latch circuit 105 and latched. Next, for the reference voltage VR at the four-bit D/A converter 103, a 1/6 Vref is selected by the analog switch 104 according to the input of a low-order selective signal, and the D/A conversion processing is executed to the low-order digital signal outputted from the gate of a four-bit latch circuit 102.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a digital signal converter that converts a digital signal into an analog signal.
Related to A converters, especially low-resolution and inexpensive D/A converters that perform high-resolution D/A conversion processing.
Regarding A converter.

[Conventional technology]

Conventionally, an 8-bit D/A converter 301 as shown in FIG. 3 has been used as a D/A converter for converting an 8-bit digital signal into an analog signal.

That is, the D/A converter 301 inputs an 8-bit digital signal from BO to B7, internally performs D/A conversion processing, and then outputs an analog signal corresponding to the digital signal. .

As mentioned above, the conventional D/A converter is a D/A converter corresponding to the number of bits of the input digital signal (for example, 8
An 8-bit D/A converter 301) was used to convert the bit digital signal to an analog signal.

[Problem to be solved by the invention]

However, conventionally, as mentioned above, a D/A converter corresponding to the bit number of the input digital signal (for example, in order to convert an 8-bit digital signal to an analog signal, an 8-bit D/A converter is used) converter), the problem was that the cost of the device itself increased.

The present invention has been made in view of the above, and an object of the present invention is to perform high-resolution D/A conversion processing without increasing the cost of the device.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a plurality of latch means that divides and launches an input digital signal, and a digital signal that inputs the digital signal latched to the latch means and converts it into an analog signal. /A conversion means and the D/A conversion means;
differentiation means for differentiating each of the plurality of digital signals in the latch means input to the A conversion means; and the D/A
an analog signal latch means for latching the analog signal after D/A conversion outputted from the conversion means; an analog signal outputted from the analog signal latch means;
The present invention provides a D/A converter including a power adding means for adding and outputting analog signals output from the converting means.

It is preferable that the differentiating means is a switching means that switches a reference voltage for the D/A converting means based on a select signal that selects a plurality of digital signals in the latch means input to the D/A converting means.

Further, it is preferable that the differentiation means is a division means that divides the specific digital signal in the latch means input to the /A conversion means by a predetermined magnification.

[For production]

The D/A converter according to the present invention divides an input digital signal into upper and lower parts, and causes each of the divided digital signals to be latched by a latch circuit.

After that, by inputting a select signal to the latch circuit, the upper digital signal inputted to the latch circuit is inputted to an inexpensive A/A converter with relatively low resolution, and after performing D/A conversion processing, the converted Outputs an analog signal. The output analog signal is further input to an analog signal latch circuit and latched.

Next, the lower digital signal that has been input to another latch circuit by inputting another select signal is input to the D/A converter, and after performing D/A conversion processing, the converted analog signal is output. do.

The analog output corresponding to the upper digital signal latched in the analog signal latch circuit and the analog output corresponding to the lower digital signal output directly from the D/A converter are differentiated and then input to an adder, and both are input to the adder. Analog values are added and output.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 1 is an explanatory diagram showing a first embodiment of the D/A converter according to the present invention, in which the upper 4-bit digital signal (BO-87) of the 8-bit digital signal (BO-87) input from the outside is ~B?) 4-bit latch circuit 101 that latches the lower 4-bit digital signal (BO-83)
A 4-bit latch circuit 102 latches the input 4-bit digital signal based on a plurality of reference voltages.
By inputting a select signal that selects the operation of the 4-bit D/A converter 103 that executes /A conversion processing and the 4-bit latch circuit 1101 or the 4-bit launch circuit 102, the standard of the 4-bit D/A converter 103 is determined. An analog switch 104 that switches the voltage value (switches the reference voltage according to the digital signal and performs addition processing) and an upper 4-bit digital signal that has been D/A converted by the 4-bit D/A converter 103. Upper V0υ latch circuit 1 that latches analog signals corresponding to (B4 to B7)
05 and the top V. An analog signal corresponding to the upper 4-bit digital signal (B4 to B7) from the LI7 latch circuit 105 and a lower 4-bit digital signal (BO to B3) output from the 4-bit D/A converter 103. An adder 106 inputs an analog signal and adds the analog values of both, and an input to the adder 106 of the lower 4-bit analog signal D/A converted by the 4-bit D/A converter 103 is switched. Analog switch 107 (upper ■).The upper 4-bit analog signal from the U7 latch circuit 105 and the analog switch 1
The lower 4-bit analog signals switched by 07 are each selected by a select signal.

The operation of the above configuration will be explained.

Of the input 8-bit digital signals, the upper digital signals (B4 to BT) are latched by a 4-bit latch circuit 101, and the lower digital signals (BO to B3) are latched by a 4-bit latch circuit 102.

The gate of the 4-bit latch circuit 101 is selected by inputting the upper select signal, and similarly, the reference voltage VR in the 4-bit D/A converter 103 is set to V2. , is selected, and the 4-bit D/A converter 103 receives the reference voltage Va.
=Lsr, D/A conversion processing is performed on the upper digital signals (84 to B7) output from the gate of the 4-bit latch circuit 101.

The analog signal after D/A conversion processing by the 4-pin I-D/A converter 103 is sent to the upper v out latch circuit 10.
5 and is latched.

Next, the gate of the 4-bit latch circuit 102 is selected by inputting the lower select signal, and similarly, the reference voltage V in the 4-bit D/A converter 103 is changed to 1/2 by the analog switch 104. 16
V,, f are selected, and the 4-bit D/A converter 103 outputs the lower digital signal (BO to B3) is subjected to D/A conversion processing.

Based on the input of the upper or lower select signal, the lower analog signal after D/A conversion processing by the 4-bit D/A converter 103 is input to the adder 106 via the analog switch 107. Also, the top V above. LI? The upper analog signal latched in the launch circuit 105 is also input to the adder 106 at the same time, and the adder 106 adds the analog values to obtain an analog output equivalent to 8 bits from the adder 106.

FIG. 2 is an explanatory diagram showing a second embodiment of the D/A converter according to the present invention, and the explanation of the same parts as those explained in FIG. 1 will be omitted.

The difference from the first embodiment shown in Fig. 1 is 4 pins)
There is no analog switch 104 for switching the reference voltage supplied to the D/A converter 103 (in the second embodiment, only the reference voltage V. is supplied), and instead, 4-bit D/A conversion is provided. A divider 201 that multiplies the lower analog signal output from the converter 103 by 1/16 is an adder 1.
Connected before 06.

In the above configuration, based on the input of the upper or lower select signal, the D/A converter 103
The lower analog signal after the conversion process is input to the divider 201 via the analog switch 107. The divider 2
The lower analog signal input at 01 is 1/16
The resultant signal is divided by a factor of 2 and input to the adder 106 . In addition, the upper analog signal latched in the upper Vouy-7"/child circuit 105 is simultaneously input to the adder 106, and the analog value is added in the adder 106. Analog output can be obtained.

In the above embodiment, an example was shown in which an 8-bit digital signal inputted by a 4-bit D/A converter is converted into an analog signal, but the number of latch circuits and the bits of the D/A converter are not limited to this. By selectively setting the number of adders and the number of adders, various combinations can be realized, and it is possible to realize even higher resolution D/A conversion processing by using an inexpensive A/A converter with lower resolution. Become.

〔Effect of the invention〕

As explained above, the D/A converter of the present invention includes a plurality of latch means for dividing and latching an input digital signal, and a plurality of latch means for dividing and latching the input digital signal, and for inputting the digital signal latched into the latch means and converting it into an analog signal. D/A to convert into signal
a converting means, a differentiating means for differentiating each of the plurality of digital signals in the latch means input to the D/A converting means, and an analog signal after D/A conversion output from the D/A converting means; The apparatus is equipped with an analog signal latch means for latching, and an adder □ stage for adding the analog signal output from the analog signal latch means and the analog signal output from the D/A conversion means and outputting the result. High-resolution D/A conversion processing can be performed without increasing costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of a D/A converter according to the present invention, FIG. 2 is a block diagram showing a second embodiment of a D/A converter according to the present invention, and FIG. FIG. 2 is an explanatory diagram showing the configuration of a conventional D/A converter. Explanation of symbols 101, 102--4-bit latch circuit 103-4-bit D/A converter 104, 107--analog switch 105--Upper ■. ut clutch path 106--adder 201-divider

Claims (3)

[Claims] (1) a plurality of latch means that divides and latches an input digital signal; a D/A conversion means that inputs the digital signal latched by the latch means and converts it into an analog signal; /A differentiation means for differentiating each of the plurality of digital signals in the latch means input to the A conversion means; and an analog signal latch means for latching the D/A converted analog signal output from the D/A conversion means. A D/A converter comprising: an addition means for adding and outputting an analog signal output from the analog signal latch means and an analog signal output from the D/A conversion means. (2) In claim 1, the differentiating means switches the reference voltage for the D/A converting means based on a select signal that selects a plurality of digital signals in the latch means input to the D/A converting means. A D/A converter characterized by being a switching means. (3) In the above-mentioned claim 1, the D/A device is characterized in that the differentiating means is a dividing means for dividing a specific digital signal in the latch means input to the D/A converting means by a predetermined magnification. converter.