JPS6063632A - Analog-digital converter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] ~/- Reprint of specification (no change in content) 聚2ixn1q! Recently, when controlling various devices, half-quadruple micro-
Using computers is becoming mainstream.

However, in a microcomputer system, everything is 1"
Since the digital processing is based on binary values (@01 or @01), the photoelectric, magnetoelectric, or thermoelectric converted analog electrical quantities that inevitably occur in device control are processed outside the microcomputer by semiconductor linear integrated circuits, transistor resistance, The circuit had to be constructed using discrete components such as capacitors and coils. Therefore, the more analog lids you handle, the more parts there are9.
% The effect of using microcomputers to increase integration, improve reliability, and reduce costs will be diminished.

Therefore, with the recent spread of macro computers, a semiconductor integrated circuit (hereinafter referred to as an A-D converter) that converts the aforementioned analog quantity into digital quantity was developed in order to take advantage of its positive benefits. It is a sequential comparison type structure,
Since there are many circuit boards, there are disadvantages in that the mounting noise level is high when integrating circuit boards, and the cost is very high because the demand for the A-D converter itself has not yet been sufficiently stimulated.

Therefore, one aspect of the present invention is to process multiple analog signals with one A-D converter using an analog switch.
The use of the present invention has the advantage of being able to efficiently utilize an expensive A-D converter. All control systems can be processed by a micro computer, and the equipment control system is
It is a cure that can increase its added value.

An embodiment of an analog-to-digital converter according to the present invention will be described with reference to FIG.

11 is a microcomputer (rjcoM
Analog signal 1, which is a separate analog signal, is applied to terminal 12, and the analog signal 1, which is a separate analog signal, is applied to terminal 12. 2 is applied to terminal 13, and analog signal 3 is applied to terminal 14.

The respective terminals 12, 13, 14 are connected to analog switches 15, 16, 17, respectively, and the output lines of the respective analog switches 15, 16, 17, 18, 19, 20 are connected to analog-to-digital conversion via the signal line 21. is applied to the input terminal of the converter (A-D converter) 22.

0N- of the three analog switches 15, 16, and 17
OFF Control is by microcomputer 1117)
Output PORT- terminals PFXO, P'E1, PFi2
．． It is controlled by the above control signal.

That is, the terminal PEQ is connected to the control terminal of the analog switch 15 by the signal line 23, and the terminal PIC1 is connected to the signal line 24.
The terminal PH2 is connected to the control terminal of the analog switch 170 through the signal line 25. Therefore terminal PEO
When the logic signal "1" is derived from the terminal P], the analog switch 15 is turned ON, and the analog signal 1 is applied to the A-D converter 22, and the logic signal "1" is similarly applied to the terminal P]101.
When the logic signal "1" is derived from the terminal PK2, the analog signal 2 is applied to the A-D converter 22, and when the logic signal "1" is derived from the terminal PK2, the analog signal #3 is applied to the A-D converter 22.
It is applied to Note that the analog switch 1
5, 16, 17 are logic "" by signal lines 25, 24, 25.
It turns off when a 0- signal is applied, p1
Further, the analog switches 15, 16, and 17 are controlled so that a plurality of analog switches 15, 16, and 17 are never turned on at the same time, and only one analog switch is always turned on and the other two switches are turned off.

The analog value +Ei applied to the input terminal of the A-D converter 22 is converted into a digital quantity in a very short time. Since the resolution of this converter is 4 bits in the example shown in FIG. 1, the input port of the microcomputer for inputting these 4 bits is PORTA. The resolution of 4 bits means that if the maximum value of analog signals to be handled is 10V, it is possible to discriminate up to 10VX-4.

The operation of the circuit shown in FIG. 1 will be explained in more detail with reference to FIGS. 2 and 3. FIG. 5 shows the instruction code stored after address 100 in the read-only memory (ROM) in FIG.

First, in step 1, a logic 1 is placed on the port B terminal PICO.
11 signal to turn on the analog switch 12. In order to perform this operation, the analog switch 12 is turned on.

Set address 100 of flOM in Figure 1 to the program counter (
command code (01110100)
is read and a logic "1" is derived from the terminal pio of FORTIH. Therefore, only the analog switch 15 is ON.
The analog signal 1 is applied to the A-D converter 22. When an analog signal is applied to the A-D converter 22 in this way, a 4-bit digital signal is derived at the output terminal, but since this A-to-digital conversion takes some time, the addresses 101 to 104 are No operation (NOP)
) and waits for the next operation until a completely A-D converted digital signal is delivered to the output terminal of the A-D converter.

After waiting for a predetermined time in this way, gtep2vc
All the digital information to which the output of the Mo-D converter is applied is read, but for this purpose, read the instruction code 0100000 at address 105 and input the contents of port A to Ace. In this way, 5top By completing step 2, the analog signal 1 is converted to a 4-bit digital signal A1 and input to the AcC.
Thereafter, necessary processing routines can be executed using the converted digital signal A1 by 5top3. This processing routine is 1 example.

Any routine such as a routine for processing the digital signal A1 to derive a desired control signal may be used.

When the processing of address 199 is completed in this way, the next step is 5.
Portl in steps 4-5! :1 is specified, the analog switch 16 is turned ON, and the analog signal 2 is applied to the Mu-D converter 22, and then the contents of the port person are imported into the ice, but such atθps is the port I!
! Except for the designation of 1, the process is performed in exactly the same way as 5tep 1 to atep X.

In this way, Btep 4~5! The 4-bit digital signal taken into JAcC is the primary 5top 6
It is processed separately. This processing routine may be any processing routine, for example, a routine for processing the digital signal A2 to derive a desired control signal.

When the processing of address 299 is completed in this way, the next step is 5.
After specifying port B 2 in top 7 and 8 and turning on the analog switch 17 and applying the analog signal 5 to the A-D converter 22, the contents of port A are set to AccK.
After importing, necessary processing is performed in 5top 9.

Therefore, if the A-D converter shown in FIG. 1 is used,
A single AD converter can convert multiple analog signals into digital signals.

The analog switches 12, 13, and 14 are, for example, one.

It is possible to construct a circuit as shown in FIG.

That is, Ql and Q5 are P-channel MOB
Transistor, Q2. Q5 is N-channel
MOB ) −j 7 jistayo], so
The relative voltage level of the control terminal 26 is “L” (
The transistor Q1 (low level) is turned on, the transistor Q2 is turned off, and the voltage of the signal line 27 becomes "H" (high level), so the transistor q6 is not turned off and the terminal 26 is 1L''. Therefore, transistor Q4 is also O.
FF.

Therefore, the analog signal present at input terminal 28 is
It is not transferred to 9. On the other hand, when terminal 26 is @''HH level, transistor Q1 becomes 0IFF.

Since the transistor Q2 is turned on, the signal line 27 is 1L''
When the transistor Q3 is turned on and the transistor Q4 is turned on, the analog signal at the terminal 28 is transferred to the terminal 29.

Therefore, the analog signal at input terminal 28 is
9.

Since both such an analog switch and an A-D converter microcomputer are constructed using a MOB l'l'# structure, the circuit configuration shown in FIG. Microcomputer circuit 5
It is possible to configure one large-scale integrated circuit (hereinafter abbreviated as LSI) in which an A-D converter and an analog switch are mounted.

FIG. 5 shows an LSI constructed in this manner, and a portion 32 surrounded by a dotted line indicates the LSI.

In FIG. 5, members denoted by the same reference numerals as in FIG. 1 are constructed in the same manner.

Figure 5 shows an A-D converter with a resolution of 4 bits, which is installed inside the 30iLs factory.
-45 is connected to the data bus 61.

Also, terminals AI, A2 . A3 is an analog switch 15,
16 and 17, and the outputs of these analog switches are respectively applied to the A-D converter 3o.

The converted blades are derived from the analog switches 15, 15, 17 and the A-D converter 6o through the signal line oL02.0.
It is configured such that instructions stored in the ROM are decoded and controlled by an instruction decoder via j04.

Therefore, m 9M of instructions for a micro 1 computer
Id, microcomputer In addition to some control instructions,
Furthermore, (a) turn on the analog switch 15 to connect the terminal A1.
Read the analog signal 1 above into the A-D converter 3°. (
b) Turn on the analog switch 16 and read the analog signal 2 on the terminal A2 into the converter 3°. (c) Turn on the analog switch 17 and read the analog signal on the terminal A3 into the fcA-D converter 3o. (d) A-D
Read the contents of converter 30 into AQQ. 4'm class instructions will be added.

Such an instruction can use a vacant instruction code, so in the case of μ00M-43 above, 11010000 is used as the instruction code in (a) above, and 11010001 is used as the instruction code in (b) above.
f: Use. 110100 as the instruction code of (c) above
10, and the instruction code of (d) above is 11010.
011 can be used.

Therefore, if a part of the instruction decoder is configured as shown in FIG. 6, the instruction code read from the ROM is applied to the signal lines L1 to L8, so the instruction code (a) is When the ROM is read, a high level signal "H" is derived only on the signal line C1 (a low level @L' is derived on the other signal lines), the analog switch 15 is turned ON, and the above command is output. When the code (b) is read from the ROM, the signal H is derived only on the signal line C2 and the analog switch 16 is turned ON. When the AiJ instruction code (C) is read from the ROM The signal ■ is derived only on the signal -3 and the analog switch 17 is turned on.
) is read from the ROM, signal H is derived only on signal line C4, and the A-D converted digital signal is A.
ce tic is loaded.

Therefore, instruction code 11 of (a) is stored at address 100 of %ROM.
If you store 010000 and the instruction code 0010110n of (a) at address 101, the PC
Execute the command by specifying 100@ground and 101 as the first
By specifying the address and executing the command, analog signal 1 on terminal A1 can be converted to a 4-bit digital signal and read from AcciC.
．． The analog signal applied to A3 can also be read into the F) ice as a digital signal through two steps.

FIG. 7 shows an embodiment in which the LSI shown in FIG. 5 is used as a control section of a copying machine.

The lamps 37 and 0 (1834
Among them, apply the terminal voltage of the atla 54.

Terminal A2 is connected to a toner concentration detection unit (35't) and a corresponding lamp (38) of CaEl (36).
A terminal voltage of 56 is applied to the terminal A6, and a terminal voltage of a detection thermistor 37' for detecting the temperature of the heater of the fixing device is applied to the terminal A6.

Even if a plurality of analog signals are stored in the L8 unit 32 in this manner, the analog signals can be sequentially read, converted into digital signals, and after necessary processing, a control signal can be derived.

FIG. 8 shows an external view of a copying machine 40 having a built-in control unit as shown in FIG. A manuscript valve 43 is arranged on the top so as to be able to swing freely around a shaft 42'ft, and a keyboard 44 for setting the number of copies and a copy start button 45 are arranged in front of this manuscript valve 43. . Note that 46 is a paper feed cassette.

Reference numeral 47 indicates a copy completion paper ejection tray.

A triangular notch 4 is formed in a part of the corner 48 of the main body 41.
9 will be provided. This notch 49 is formed in the upper plate 5 as shown in FIG.
0. Lower plate 51. The upper board 50 consists of the standing board 52.
A light transmitting portion 55 is provided in a part of the light transmitting portion 53, and the Ca, which is a light receiving element, is provided at a position opposite to the notch 49 of the light transmitting portion 53.
Fixed at 534ft. On the other hand, a light-transmitting part 54 is provided in a part of the lower plate 51 facing the light-transmitting part 53, and the lamp 57, which is a light-emitting element, is fixed to a position opposite to the notch 49 of this light-transmitting part 54. .

Therefore, the light emitted from the rung 37 is configured to reach the CDS 54.

If the original 55 is inserted into this notch 49.

An output signal corresponding to the amount of light transmitted through the original 55 can be obtained from the CDS 34 .

In short, since it is possible to know the bank ground of the original, the copying apparatus can be controlled according to the back ground of the original based on the output of the detection unit.

Note that the detector 5 of the switch 56 is mounted on a part of the standing board 52.
7 is extended, and the original document 55 is placed.

If the switch 56 is configured to be turned on by inserting it into the notch 49 and pressing the detector 57 in the direction of the arrow T, the ON output of the switch 56 will be treated as a single signal as 54 It is also possible to convert the output into a digital signal. In this case, for example, the ON output of the switch 56 causes the RO shown in FIG.
All you have to do is specify address 100 of M.

With the above configuration, an inexpensive switching circuit can be provided in an expensive analog-to-digital converter, and one analog-to-digital converter can be used efficiently.

Furthermore, when a system in which a microcomputer and an analog-to-digital converter are connected is housed in one large-scale integrated circuit, there is a limit to the degree of integration in incorporating multiple analog-to-digital converters; If we adopt 1
A single analog-to-digital conversion circuit apparently has the same function as a system equipped with multiple analog-to-digital conversion circuits, which is very advantageous in terms of integration.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an analog-to-digital converter R according to the present invention, FIG. 2 is a flowchart showing the circuit operation of FIG. 1, FIG. 5 is an instruction code diagram stored in the ROM of FIG. The figure is a circuit diagram showing the switch used in Figure 1.
The figure is a circuit diagram showing an analog-to-digital converter according to another embodiment of the present invention, FIG. 6 is a circuit diagram showing a part of FIG. 5 in detail, and FIG. Figure 8 is an external view of a copying machine to which the present invention is applied;
9th m1A+B is a perspective view and a BB' cross-sectional view showing a background concentration detection unit that can be applied to the present invention. Here 11 is a microcomputer, 15°16.
17 is a switch, and 22.30 is an A-D converter. Figure 4 Procedural amendment (method) 1 Indication of the case 1982 Patent application No. 61332 2 Name of the invention Analog-to-digital converter 3 Relationship with the person making the amendment 1 Patent applicant 1 Place Tokyo 3-3 Shimomaruko, Dai 1n Ward (T-2 name)
(10(1) Canon Co., Ltd. Representative Ryu Kaku 3rd Department 4th Agent Residence) Kei 146 Tokyo Metropolitan University [3-30-2 Shimomaruko, N-ku
5. Date of amendment order: August 28, 1980 (shipment date) 6. Specification subject to amendment and drawings Engraving (no change in content) Procedural amendment (voluntary) April 27, 1980 Kazuo Wakasugi, Commissioner of the Patent Office T, 1-2, Name of invention analog-to-digital converter 3, case of person making amendment Relationship with Patent applicant address 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (100
) Canon Co., Ltd. Representative: Ryu Kaku, Department 4, Agent address: 3-30-25 Shimomaruko, Ota-ku, Tokyo 146, Specification subject to amendment: Document 6, Contents of the amendment: Scope of claims, as attached. to correct. 2. Scope of Claims Conversion means for converting analog data into digital data, processing means for performing processing based on digital data from the conversion means, and timer means for controlling input of the digital data to the processing means. An analog-to-digital conversion device characterized by having:

Claims (1)

[Claims] It has a conversion means for converting analog data into digital data, a processing means for performing processing based on the digital data from the conversion means, and a timer means for controlling the input of the digital data to the processing means described in item 2 above. An analog-to-digital conversion device characterized by: a converting means, a processing means for processing digital data from the converting means, and a timer means for controlling input of the digital data to the processing means. An analog-to-digital conversion device featuring: