JP2003045984A - Digital and analog converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive a degree of freedom of design and improvement of design efficiency when a single channel or multi-channels of a DA converter are contrived. SOLUTION: A digital and analog converter is provided with a DA conversion circuit macro cell 3 making a digital and analog (DA) conversion circuit having a current source outputting prescribed current and a logic circuit selecting the current source independent as a macro cell, and a reference voltage generation circuit macro cell 2 making a reference voltage generation circuit generating reference voltage potential determining an output current value of the DA conversion circuit independent as the macro cell. A multi-channel DA converter 7 is obtained by constituting a one-channel DA converter, making one reference voltage generation circuit macro cell 2, and arranging a plurality of the DA conversion circuit macro cells 3 so as to be adjacent thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital-analog converter mounted on a semiconductor device or a printed circuit board.

[0002]

2. Description of the Related Art In recent years, along with the widespread use of semiconductor devices for digital signal processing, digital-analog (hereinafter abbreviated as DA) converters are widely used as output means. Hereinafter, a conventional digital-analog converter will be described with reference to the drawings.

FIG. 6 is a diagram for explaining the structure of a conventional DA converter. From FIG. 6, the conventional DA converter 103
Is a reference voltage generation circuit unit 101 and a DA conversion circuit unit 102.
And are configured as the same macro cell (thick line in FIG. 6). The DA conversion circuit unit 102 has a current source that outputs a predetermined current and a logic circuit that selects the current source. The reference voltage generation circuit unit 101 determines the output current value of the DA conversion circuit unit 102. However, the reference voltage potential is generated.

According to the DA converter having such a configuration, D
When attempting to increase the number of channels based on the A converter 103, the following method is used.

First, FIG. 7 is a diagram for explaining the configuration of a conventional multi-channel DA converter. As shown in FIG. 7, the multi-channel DA converter 104 is configured by arranging the macro-cell DA converter 103 shown in FIG.

FIG. 8 shows another conventional multi-channel DA.
The figure for demonstrating the structure of a converter is shown. First, FIG.
As shown in FIG. 6A, the macrocell DA shown in FIG.
The converter 103 is divided into a reference voltage generation circuit unit 105 obtained by a new division process and a DA conversion circuit unit 106 obtained by a new division process. Then, as shown in FIG. 8B, the multi-channel DA converter 107 has the DA converter 103 obtained by the new division processing shown in FIG. 8A in the macrocell DA converter 103 shown in FIG. The circuit section 106 is configured by additionally arranging only for multiple channels.

[0007]

However, when attempting to increase the number of channels using the conventional DA converter, there are the following problems. First, in the case of configuring a multi-channel DA converter, it suffices that one common reference voltage generation circuit section 101 is provided in common.
According to the converter 104, the macrocell DA converter 1
Since 03 is placed as it is for multiple channels,
The extra reference voltage generating circuit section 101 for multiple channels is provided. As a result, the multi-channel DA converter 104 has a problem that the layout area increases. Further, there is a problem that the consumption current increases due to the presence of the extra reference voltage generation circuit section 101.

Further, according to the multi-channel DA converter 107 shown in FIG. 8, the reference voltage generating circuit section 101 and the DA conversion circuit section 102 are newly divided from the macrocell DA converter 103 shown in FIG. However, there is a problem that the design period is spent because it is necessary to make it possible. Further, when the number of channels is increased, only one reference voltage generation circuit section 101 is required in common, so that an extra reference voltage generation circuit section 105 is generated when the DA converter 103 is newly divided. There was a problem.

The present invention has been made to solve the above problems, and it is possible to improve not only the DA converter having a single channel but also the degree of freedom in design when increasing the number of channels and the design efficiency. It is an object of the present invention to provide a DA converter.

[0010]

In order to solve this problem, a digital-analog converter according to claim 1 of the present invention comprises a current source for outputting a predetermined current, and a logic circuit for selecting the current source. One digital-to-analog conversion circuit macrocell having a digital-to-analog conversion circuit as a macrocell and one independent reference-voltage generation circuit that generates a reference voltage potential for determining the output current value of the digital-to-analog conversion circuit as a macrocell. It is a single-channel digital-analog converter which is formed by combining the reference voltage generating circuit macrocell of 1.

According to a second aspect of the present invention, in the digital-analog converter, a plurality of independent digital-analog conversion circuits each having a current source for outputting a predetermined current and a logic circuit for selecting the current source as a macro cell are provided. A combination of the individual digital-to-analog conversion circuit macrocells and one independent reference-voltage generation circuit macrocell as a macrocell having a reference-voltage generation circuit that generates a reference-voltage potential that determines the output current value of the digital-analog conversion circuit. It is characterized by being a multi-channel digital-analog converter.

According to a third aspect of the present invention, in the digital-analog converter according to the first aspect or the second aspect, the reference voltage generating circuit macrocell and the digital-analog converting circuit macrocell are Extracting from a macrocell database including a reference voltage generation circuit macrocell group including a plurality of the reference voltage generation circuit macrocells and a digital-analog conversion circuit macrocell group including a plurality of the digital-analog conversion circuit macrocells. Is.

The digital-analog converter according to claim 4 of the present invention is the digital-analog converter according to claim 2 or 3, wherein the multi-channel digital-analog converter is the plurality of digital-analog converters. The analog conversion circuit macrocell is characterized by including a power supply wire extending from the power supply terminal and the ground terminal to the outside, and a power supply / ground wiring common macrocell that bundles the ground wires.

According to a fifth aspect of the present invention, there is provided the digital-analog converter according to the fourth aspect, wherein the power / ground wiring common macrocell is one of adjacent digital-analog conversion circuit macrocells. Of the power supply terminals to the intersections of the bundled power supply wires, and the distances from the ground terminals of the adjacent digital-analog conversion circuit macrocells to the intersections of the bundled ground wires are equalized. .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) A digital-analog (hereinafter abbreviated as DA) converter according to Embodiment 1 of the present invention is one in which a reference voltage generation circuit and a DA conversion circuit which constitute a DA converter are made into macrocells.

FIG. 1 shows a DA according to the first embodiment of the present invention.
It is a figure for demonstrating the structure of a converter. As shown in FIG. 1, the single-channel DA converter 1 includes a reference voltage generation circuit macrocell 2 and a DA conversion circuit macrocell 3. The DA conversion circuit macrocell 3 is an independent DA conversion circuit having a current source that outputs a predetermined current and a logic circuit that selects the current source, as a macrocell. The reference voltage generation circuit macrocell 2 is an independent macrocell that determines the output current value of the DA conversion circuit and generates a reference voltage potential.

In FIG. 1, the reference voltage generating circuit macrocell 2 and the DA converting circuit macrocell 3 are made to exist independently of each other. Therefore, when the single-channel DA converter 1 is constructed, the reference voltage generating circuit macrocell 2 is set to one. And DA
A single conversion circuit macrocell 3 was combined.

As described above, according to the DA converter of the first embodiment, the reference voltage generating circuit macrocell and the DA converting circuit macrocell are independently provided, so that the DA converter is easily configured. Can, in addition,
One of the reference voltage generating circuit macrocell and the DA converting circuit macrocell can be used as a component of another DA converter. In addition, it is possible to improve the degree of freedom in design and the design efficiency when increasing the number of channels.

(Embodiment 2) A DA converter according to a second embodiment of the present invention extracts the best reference voltage generation circuit macrocell and the DA conversion circuit macrocell in order to constitute the best DA converter. is there.

FIG. 2 shows a DA according to the second embodiment of the present invention.
It is a figure for demonstrating the macrocell database which extracts the macrocell which comprises a converter. As shown in FIG. 2, the macro cell database 6 stores a reference voltage generation circuit macro cell group 4 including a plurality of reference voltage generation circuit macro cells 2 and a DA conversion circuit macro cell group 5 including a plurality of DA conversion circuit macro cells 3.

In FIG. 2, in order to construct a desired DA converter, an optimum reference voltage generation circuit is selected from the reference voltage generation circuit macrocell group 4 and the DA conversion circuit macrocell group 5 stored in the macrocell database 6. Macro cell 2
And the DA conversion circuit macrocell 3 are extracted and combined.

As described above, according to the DA converter of the second embodiment, the DA converter stored in the macrocell database is
From each of the reference voltage generation circuit macrocell group and the DA conversion circuit macrocell group, each macrocell is extracted to obtain the best DA.
Since the converter is configured, it is possible to easily create an optimal combination of DA converters. In addition, it is possible to improve the degree of freedom in design and the design efficiency when increasing the number of channels.

In the second embodiment, the optimum DA converter is configured by combining the macro cell groups existing in the macro cell database. However, among the reference voltage generating circuit macro cell and the DA converting circuit macro cell, , Either one is extracted from the macrocell group in the existing macrocell database, and the other is a combination to which the newly created macrocell is applied.
A converter may be configured.

(Embodiment 3) A DA converter according to Embodiment 3 of the present invention constitutes a multi-channel DA converter. FIG. 3 shows a second embodiment of the present invention.
It is a figure for demonstrating the structure of a channel DA converter. As shown in FIG. 3, the 2-channel DA converter 7 includes one reference voltage generating circuit macrocell 2 and two DA converting circuit macrocells 3.

First, the macrocells which have been independently made in advance are
A reference voltage generating circuit macrocell 2 and a DA converting circuit macrocell 3 are prepared. One reference voltage generating circuit macrocell 2 is provided adjacent to it, and two DA converting circuit macrocells 3 are provided.
Place them individually. With this configuration, the 2-channel DA converter 7 can be obtained.

As described above, according to the DA converter of the third embodiment, the DA converter circuit macrocells having the required number of channels are arranged adjacent to one reference voltage generating circuit macrocell to perform multi-channel DA conversion. Since the converter is configured, a multi-channel DA converter can be easily created. Further, in the past, an extra reference voltage generating circuit section was generated in order to create a multi-channel DA converter, but the extra circuit is not constructed. Further, since the extra reference voltage generating circuit section can be reduced, the layout area can be reduced and the power consumption can be reduced as compared with the conventional case.

In the third embodiment, the two-channel DA converter has been described as an example. However, the number of channels is not limited to two, and a multi-channel DA converter having three or more channels has the same method. Can be created by using, and the same effect can be obtained.

Further, the reference voltage generating circuit macrocell and the DA converting circuit macrocell constituting the multi-channel DA converter are the same as those in the first and second embodiments.
As shown in, each macro cell may be configured by a newly created one, or selected from the macro cell database and configured.

(Fourth Embodiment) A DA converter according to a fourth embodiment of the present invention comprises a multi-channel DA converter in which a macro cell for common power / ground wiring is formed. FIG. 4 is a diagram for explaining the configuration of the DA converter according to the fourth embodiment of the present invention.

From FIG. 4, each of the two DA converter macro cells 3 has a power supply (hereinafter referred to as VDD) terminal 8
And a ground (hereinafter referred to as VSS) terminal 9. The VDD terminals 8 provided in the adjacent DA conversion macro cells 3 are bundled to form a VDD wiring 10 and V
It is connected to the DD pad 12. Also, the adjacent DA
The VSS terminals 9 provided in the conversion circuit macrocell 3 are bundled to form a VSS wiring 11 and connected to the VSS pad 13. The above-mentioned VDD / VSS wiring common macrocell 14 is composed of the VDD wiring 10 and the VSS wiring 11. In addition, the 2-channel DA converter 15 with the common macro cell for VDD / VSS wiring
Is composed of a 2-channel DA converter 7 and a VDD / VSS wiring common macrocell 14. Note that with respect to other configurations, the same parts as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

2 constituting the 2-channel DA converter 7
Since the DA conversion circuit macrocells 3 each have the same shape, the relative positional relationship between the VDD terminal 8 and the VSS terminal 9 is also maintained. Where VD
The D / VSS wiring common macrocell 14 has the VDD wiring 1
0 and the common impedance of the VSS wiring 11 are considered in advance, the VDD pad 12 and the VSS pad 13 to D
The wiring resistances to the VDD terminal 8 and the VSS terminal 9 provided in the A conversion circuit macrocell 3 are equalized.

FIG. 5 is a diagram for explaining the wiring configuration of the VDD / VSS wiring common macrocell of FIG. 4 to the VDD wiring. From FIG. 5, the wiring length a16 and the wiring length b17
Is the V provided in each of the adjacent DA converter macrocells.
It is the distance from the DD terminal to the intersection where the VDD wires extending to the outside are bundled. For other configurations,
The same parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 5, the wiring length a16 and the wiring length b
The lengths of 17 were made to be the same. With such a configuration, the common VDD / VSS wiring macrocell 14 in which the wiring resistance from the VDD pad 12 to the power supply terminals 8 provided in each of the two DA conversion circuit macrocells 3 is made uniform is configured. ing.

In the fourth embodiment, only the VDD wiring side is shown in the drawing for ease of explanation, but
The same configuration is applied to the VSS wiring side. As described above, according to the DA converter according to the fourth embodiment, VDD / VS provided in each of the adjacent DA conversion circuit macrocells.
Since the length from the S terminal to the intersection at which the VDD and VSS wirings extending to the outside are bundled is the same, the adjacent DA
It becomes easy to add the common VDD / VSS wiring macro cell in which the impedance of the VDD / VSS wiring from the VDD / VSS terminal of the conversion circuit macro cell to the LSI pad is equalized in advance. That is, it is possible to prevent characteristic fluctuation due to voltage drop of the adjacent DA conversion circuit macro cell.

In the fourth embodiment, the two-channel DA converter has been described as an example, but the number of channels is not limited to two, and the same method can be applied to a multi-channel DA converter having three or more channels. Can be created by using, and the same effect can be obtained.

[0036]

As described above, according to the digital-analog converter of the first aspect of the present invention, the digital-analog conversion having the current source that outputs a predetermined current and the logic circuit that selects the current source. One independent digital-analog conversion circuit macro circuit as a macro cell and one reference voltage generation circuit independent as a macro cell a reference voltage generation circuit for generating a reference voltage potential that determines the output current value of the digital-analog conversion circuit. Since it is a single-channel digital-analog converter combined with a macro cell, it becomes easy to use one of the reference voltage generating circuit macro cell and the DA converting circuit macro cell as a component of another DA converter. Therefore, the degree of freedom in design and the design efficiency can be improved.

Further, according to the digital-analog converter of the second aspect of the present invention, a digital-analog converter circuit having a current source for outputting a predetermined current and a logic circuit for selecting the current source is independently used as a macrocell. The plurality of digital-analog conversion circuit macrocells and a single reference-voltage generation circuit macrocell having a reference voltage generation circuit for generating a reference voltage potential that determines the output current value of the digital-analog conversion circuit as a macrocell are combined. Since it is a multi-channel digital-to-analog converter, it is possible to reduce the components of the reference voltage generating circuit section for multi-channels found in the conventional technology, which reduces the layout area and consumes less power. Can be realized.

According to a third aspect of the present invention, there is provided the digital-to-analog converter according to the first or second aspect, wherein the reference voltage generating circuit macrocell and the digital-to-analog conversion circuit are included. Since the macro cell is to be extracted from the macro cell database including the reference voltage generation circuit macro cell group including the plurality of reference voltage generation circuit macro cells and the digital analog conversion circuit macro cell group including the plurality of digital analog conversion circuit macro cells. It is possible to easily create an optimal combination of DA converters. Also,
It is possible to improve the degree of freedom in design and the design efficiency when increasing the number of channels.

According to a fourth aspect of the present invention, there is provided the digital-analog converter according to the second or third aspect, wherein the multi-channel digital-analog converter is a plurality of the plurality of digital-analog converters. Since the power supply wiring extending to the outside from each power supply terminal and the ground terminal of the digital-analog conversion circuit macrocell and the common power supply / ground wiring macrocell that bundles the ground wiring are provided, the voltage drop of the adjacent DA conversion circuit macrocell It is possible to prevent the characteristic variation due to.

According to a fifth aspect of the present invention, there is provided a digital-to-analog converter according to the fourth aspect, wherein the power / ground wiring common macrocells are adjacent digital-analog conversion circuit macrocells. Since the distance from each power supply terminal to the intersection where the power supply wires are bundled is made equal, and the distance from each ground terminal of the adjacent digital-analog conversion circuit macrocell to the intersection where the ground wires are bundled is made equal, It is possible to prevent the characteristic variation due to the voltage drop of the D / A conversion circuit macro cell.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a configuration of a DA converter according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a macrocell database for extracting macrocells included in the DA converter according to the second embodiment of the present invention.

FIG. 3 is a 2-channel DA according to a third embodiment of the present invention.
Diagram for explaining the configuration of the converter

FIG. 4 is a diagram for explaining the configuration of a DA converter according to a fourth embodiment of the present invention.

FIG. 5 is a diagram for explaining the wiring configuration of VDD wiring from the VDD / VSS wiring common macrocell of FIG. 4;

FIG. 6 is a diagram for explaining the configuration of a conventional DA converter.

FIG. 7 is a diagram for explaining the configuration of a conventional multi-channel DA converter.

FIG. 8 is a diagram for explaining the configuration of another conventional multi-channel DA converter.

[Explanation of symbols]

1 DA Converter 2 Reference Voltage Generation Circuit Macrocell 3 DA Conversion Circuit Macrocell 4 Reference Voltage Generation Circuit Macrocell Group 5 DA Conversion Circuit Macrocell Group 6 Macrocell Database 7 2 Channel DA Converter 8 VDD Terminal 9 VSS Terminal 10 VDD Wiring 11 VSS Wiring 12 VDD pad 13 VSS pad 14 VDD / VSS wiring common macro cell 15 2-channel DA converter with VDD / VSS wiring common macro cell 16 wiring length a 17 wiring length b 101 reference voltage generation circuit unit 102 DA conversion circuit unit 103 DA conversion Units 104 and 107 Multi-channel DA converter 105 Reference voltage generation circuit section 106 obtained by new division processing DA conversion circuit section obtained by new division processing

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Heiji Ikoma             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5F038 BB00 CA03 CD02 CD12 DF03                       DF08 EZ20                 5F064 AA06 BB40 DD13 DD20 DD24                       DD36 EE08 EE42 EE52                 5J022 AB06 BA06 CB01 CG01

Claims (5)

[Claims] 1. A single digital-analog conversion circuit macrocell, which independently has a digital-analog conversion circuit having a current source that outputs a predetermined current and a logic circuit that selects the current source as a macrocell, and the digital-analog conversion circuit. A single-channel digital-analog converter in which a reference voltage generating circuit for generating a reference voltage potential for determining an output current value is combined as a macro cell with one independent reference voltage generating circuit macro cell. Digital-to-analog converter. 2. A plurality of independent digital-analog conversion circuit macrocells, each of which has a digital-analog conversion circuit having a current source for outputting a predetermined current and a logic circuit for selecting the current source as a macrocell, and the digital-analog conversion circuit. A multi-channel digital-analog converter in which a reference voltage generating circuit for generating a reference voltage potential for determining an output current value is combined as a macro cell with one independent reference voltage generating circuit macro cell. Digital-to-analog converter. 3. The digital-analog converter according to claim 1 or 2, wherein the reference voltage generating circuit macrocell and the digital-analog converting circuit macrocell include a plurality of reference voltage generating circuit macrocells. A digital-analog converter characterized by extracting from a macrocell database comprising a macrocell group and a digital-analog conversion circuit macrocell group consisting of a plurality of the digital-analog conversion circuit macrocells. 4. The digital-to-analog converter according to claim 2 or 3, wherein the multi-channel digital-to-analog converter is external from power supply terminals and ground terminals of the plurality of digital-analog conversion circuit macrocells. A digital-to-analog converter characterized in that it comprises a power supply wiring extending to a line and a macrocell for common power supply / ground wiring that bundles the ground wiring. 5. The digital-analog converter according to claim 4, wherein the power / ground wiring common macrocells have equal distances from the respective power supply terminals of adjacent digital-analog conversion circuit macrocells to the intersections of the bundled power supply wirings. The digital-to-analog converter is characterized in that the distances from the ground terminals of adjacent digital-to-analog conversion circuit macrocells to the intersections where the ground wires are bundled are made equal.