JPS58123131A - Input device - Google Patents

Abstract

PURPOSE:To reduce noise and unnecessary radiation and to decrease the number of wirings between a switch group and a digital circuit 4, by constituting such a matrix that DC voltages are applied to key contacts. CONSTITUTION:Row lines 2a, 2b, 2c, and 2d of the key switch group 1 are connected to one terminal +V of a power source through resistances 5a, 5b, 5c, and 5d respectively. Further, the row lines 2a-2d are connected to input terminals of voltage comparators 6a-6d having a threshold voltage V1 and their outputs are connected to the input terminal part 4c of the digital circuit 4. Column lines 3a-3d, on the other hand, are connected to the other terminal G of the power source through resistance groups 7a, 7b, 7c, and 7d as well as the row lines 2 and further connected to the input terminal part 4D of the digital circuit 4 through voltage comparators 8a-8d.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called matrix 11 input device that has contact points at the intersections of a plurality of column lines and row lines, and provides an input device that is less likely to generate noise, has less noise, and has less unnecessary radiation. It is something to do.

Conventionally, there are static and dynamic types of key input devices that make contacts (keys) at the intersections of multiple column lines and row lines.The static type has no noise because a direct current is applied to the contacts. However, it has the disadvantage that it requires a large number of wires between the switch that opens and closes the contact and the digital circuit that inputs it.

FIG. 1 shows a conventional example of a dynamic input device. Reference numeral 1 denotes a key switch group having contacts arranged in a matrix, and its row line group 2 is connected to an output terminal section 4A of a digital circuit 4. Here, the digital circuit 4 is, for example, a microcomputer.

The 10,000 column (13 is connected to the input terminal section 4B of the digital circuit 4. A pulse voltage as shown in FIG. 2 is applied to the output terminal section 4A of the digital circuit. However, the above dynamic type Since the contacts are arranged in a matrix, the number of wires between the switch that opens and closes the contacts and the digital circuit is small, but since a pulsed AC voltage is applied to the contacts, it is easy to generate itt and unnecessary radiation. It has the disadvantage that it can also cause

The present invention solves the above-mentioned conventional drawbacks, eliminates the cause of noise and unnecessary radiation by applying a DC voltage to the contacts, and provides a novel input device in which the contacts are arranged in a matrix. An embodiment of the present invention will be described below based on the drawings.

Is Figure 3 the first implementation? 11, the row lines 2a, 2b, 2c, 2d of the key switch group 1 are connected to one end of the power supply + via resistors 5a, 6b, 5c, 5d, respectively.
■Connected to. Also, row line 2a.

2b, 2c, 2d are voltage comparators 6 with a threshold voltage of vl.
The voltage comparators 6a, 6b, 6c are connected to the respective input terminals of the voltage comparators 6a, 6b, 6c, and 6d.

The output of 6d is connected to the input terminal section 4C of the digital circuit 4. On the other hand, column lines 3a, 3b, 3c.

Similarly to row line group 2 and i, 3d is a resistance group 7a.

It is connected to the other end G of the power supply via 7b, 7G, and 7d, and is also connected to the input terminal section of the aromatic circuit 4 through the voltage comparators aa, ab, be, and sci, respectively, which have a threshold voltage of 2. Connected to 4D.

Here, voltage comparators 6a, 6b...C, conhalator I
Although it is possible to easily configure the inverter by using a CMOS inverter, an operational amplifier, etc., in this embodiment, a CMOS inverter is used. In this case, the threshold voltage v1°v2 can be easily set by changing the power supply voltage applied to the CMOS inverter.

If no key is pressed, line 2a.

... becomes the power supply voltage V of the key switch section.

Here, the threshold voltage V of the voltage comparators 6a...6d is vl
<When set to V, the row lines 2a...2d all become H" level. Also, the voltage of the column line group 3 becomes Ov, and the threshold voltage v2 of the voltage comparators 8a...-a d is set to ■2>o When set to , the column line group 3 becomes "L" level.

Next, consider the case where a key switch is pressed.

For example, consider a case where key switch 1bC is pressed.

Pass the resistor 6b from the power supply +V to the row line 2b.

Current flows through switch Ibc column line 3C and through resistor 7C. Therefore, the resistance value of the resistor 6b is set to R1゜vl・v
2 is set to , the row line 2b is "L" level and the column line (support) is "
H level, and it is possible to detect that the key switch 1 ha has been pressed.

That is, the above-mentioned 1IA1111￥1. By combining with the voltage condition and setting vl and v2, it is possible to detect whether the switch has been pressed.

According to the above configuration, since a DC voltage is applied to the key switches 1aa to 1dd, it is possible to realize an input device that does not generate noise or unnecessary radiation unlike the conventional input device.

Furthermore, unlike the conventional static type, the key switches are arranged in a matrix, so the digital circuit 4
It has the great advantage of requiring less number of devices.

FIG. 4 shows a g2 embodiment of the present invention, which is a further improvement of the first embodiment and is characterized by a pixel configuration that does not use voltage comparators with different threshold voltages.

Rows d3a, 3b, 3a, sd of key switch group 1
is connected to the power supply G through a resistor 7 and directly to the input terminal of the digital 1o circuit 4.

One row of lines 2a to 2d connects the resistors 6a to 6d with the power supply +
V, and is also connected to the power supply G through a series circuit of a diode 61a and a resistor 62a (others 61b, 62b, etc.), and connects the digital circuit 4 (microcomputer in this embodiment) from the connection point of the diode 61a and resistor 62a. is input to the input terminal section 4C.

Here, it is assumed that the threshold voltage of the input terminal portion 4C of the digital circuit 4 is V, r, and the forward direction' voltage of the diodes 61a to 61d is vL). Furthermore, if the resistance value R3 of the resistors 62a to 62d is made sufficiently larger than the resistance value H1 of the resistors 6a to 6d, the voltage of the rows d2a to 2d input to the digital circuit 4 when no key is pressed is V -V, and the voltage of the lead wire becomes 0.

From this, as a condition for the threshold voltage vT, 0 (VT(:V-VL) becomes.

becomes.

Therefore, if R1 and R2 are selected so that the threshold voltage vT satisfies the above two conditions, it is possible to detect that the key isona is pressed. Further, the diodes 61a to 61d can be replaced with resistors if there is margin in the range of the threshold voltages v and r.

1. FIG. 6 shows a third embodiment of the present invention in which dl and R2 are selected with more leeway than in the second embodiment. In this embodiment, the row line group has the same structure as in the second embodiment. Furthermore, the drawing line group has exactly the same structure as the row line group. That is, the column line 3a is connected to '41.' through the resistor 7&. It is connected to one end G of the power supply, and is connected to this power supply G through a series circuit of a reverse diode 81a and a resistor 82a, and further connected to the power supply G through a series circuit of a reverse diode 81a and a resistor 82a.
The signal is input to the input terminal section 4D of the digital circuit 4 from the connection point a. The same applies to the other column lines 3b to 3d.

Here, as a pressure condition for the threshold +1[i', when the key is not pressed, if the resistance l1fR4 of the resistors 82a to 82d is made sufficiently large compared to the resistance value H2, vD<v,
(If the v-vD key is pressed, then Furthermore, the diodes 81a to g1d can be replaced with resistors as in the second embodiment.

As is clear from the embodiment described in L, the present invention uses a method in which a direct current voltage is applied to the key contacts and forms a matrix, so noise and unnecessary radiation are extremely low. A key human-powered device with fewer wires can be realized.

The present invention is also particularly useful when the digital circuit is a microcomputer or the like. Since the number of input terminals and the number of output terminals are set in advance in a one-chip microcombinator, depending on the application, there may be a shortage of output terminals and a surplus of input terminals. In conventional matrix-type manual devices, both output terminals and input terminals are conveniently used, but the present invention has a connection port only at the input terminal.
It is possible to construct the human-powered device f1 without necessarily requiring complicated circuits.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional human-powered device, Fig. 2 is a waveform diagram of its main parts, dXa diagram is a circuit diagram of an embodiment of the present invention, Fig. 4,
FIG. 5 is a circuit diagram of each other embodiment. 1...Key switch group, 2-...Row line column, 2a, 2b, 2c, 2d 60
600m row line, 3-------column line group, 3a, 3b
, 3c , ad *, , , , column line, 4C14D
, ---- Input terminal section, 5a, 5b, 6c, 5d・
...Resistance, 6a, 8b, 6c, 6d...
Voltage comparator, 7a, end, 7c, 7d... Resistor, 8 a, 8 b, 8 c, 8 d --
----Voltage comparator, 61a. 61b, 61C, 61d---diode, 62a. 62b, 62C, 62d, -,,, resistance, 81
a, 81 b. 81 c 81 d = diode, 82a+, 82
b. 82c 82d...Resistance. Name of agent: Patent attorney Toshio Nakao and one other person Wk
1 Figure 2

Claims (3)

[Claims] (1) It has a plurality of column lines and a plurality of row lines, and a contact point that can be opened and closed is provided at each intersection of the column line and the row line, and the column line is connected through a first resistor group, and a power supply is provided. and to the input terminal of a first group of voltage comparators having a first threshold voltage, the row lines being respectively connected to a second terminal of the power supply through a second group of resistors. terminal and to an input terminal of a second voltage comparator group having a second threshold voltage; An input device characterized in that the open/close state of the contact is output to the output terminal of the second voltage comparator group. (2) A plurality of column lines and a plurality of row lines are provided, contacts that can be opened and closed are provided at the intersections of the column lines and the lines, respectively, and the front 8 row lines are connected to the first resistance group. is connected to the first terminal of the power supply through a second resistor or a first diode and a third resistor, and is connected to the second terminal of the power supply through a second resistor or a first diode and a third resistor; Connect the connection point between the diode and the third resistor with a digital
! :! connected to the first input terminal portion of the circuit, and the row line is connected to the first input terminal portion of the circuit;
An input device characterized in that the input device is connected to a second terminal of the power source through a fourth group of resistors, and is also connected to a second input terminal section of the digital circuit. (3) Connect the row lines to the second terminal of the power supply through the fourth resistor group, and connect them to the first terminal of the power supply through the fifth resistor or the second diode and the sixth resistor. and the connection point between the sixth resistor or the second diode of MiJ and the sixth resistor is connected to the second input terminal of the digital circuit. The input device according to item 2.