JPH0566884A - Composit switch module and dynamic scanning circuit - Google Patents

Abstract

PURPOSE:To improve reliability of equipments by simplifying a matrix structure of a mechanical switch and a light emitting display element such as LED and reducing the number of parts of a control circuit. CONSTITUTION:Whether to drive an LED 102 or to make a mechanical switch 108 control is selected by a transistor 107 based upon the control signal to a control changeover terminal 114. The driving of the LED 102 is controlled by an AND circuit consisting of transistors 103 and 104 with a line control input/output terminal 112 and a column control input terminal 113 taken as inputs. The operational output from the mechanical switch 108 is applied to the line control input/output terminal 112 by a transistor 110. The configuration of a matrix dynamic scan control circuit which uses plural composite switch module, thus constituted, can be significantly simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch for equipment which requires a plurality of switches such as a button telephone and a light emitting display element such as a plurality of light emitting diodes (hereinafter referred to as LEDs) corresponding to the switches. The present invention relates to a display switch, a composite switch module necessary for inputting switch information while dynamically scanning them, and controlling LED lighting, and a dynamic scan control circuit using the same.

[0002]

2. Description of the Related Art In recent years, the spread of information equipment has spread widely to ordinary households. Therefore, simplification of the configuration and improvement of information property have been demanded. Similar improvements have been made to the conventional dynamic scan control circuit including switches and LEDs. An example of this conventional dynamic scan control circuit is shown in FIG.

In FIG. 5, the matrix structure of the LED and the matrix structure of the mechanical switch has a 4 × 4 structure. The anode side of the display LEDs 501 to 516 has a current limiting resistor 553 that sets the brightness of the LED for each row.
Through 552 to emitter-follower type transistors 549 through 552, respectively, capable of supplying a sufficient drive current to the LED. On the other hand, the cathodes that make the columns of the LEDs 501 to 516 equal to each other are connected to the collectors of the transistors 565 to 568 whose emitters are grounded. The bases of the transistors 565 to 568 are output terminals of the microcomputer 581. The first row LED row control terminal 569, the second row LED row control terminal 570 and the third row LED
The row LED row control terminals 571 and the fourth row LED row control terminals 572 are respectively connected.

The mechanical switches 517 to 532 form a matrix via reverse bias prevention diodes 533 to 548, respectively. The cathodes in the same row of the reverse bias prevention diodes 533 to 548 are connected to each other, and are connected to the preceding transistors 565 to 568, respectively. On the other hand, one ends of the mechanical switches of the same row are connected to each other, and are the input terminals of the microcomputer 581, that is, the row control terminal 573 for the first row mechanical switch, the row control terminal 574 for the second row mechanical switch, and the third row mechanical switch. Row control terminal 575, row control terminal 5 for the fourth row mechanical switch
76 respectively. Bias resistors 557 to 560 for pull-up are connected to the respective control terminals, and if there is no input to the mechanical switches 517 to 532, the row control terminals 573 to 576 are respectively provided.
Is always in a high level (hereinafter abbreviated as H) state. on the other hand,
The bases of the transistors 565 to 568 are connected via the current limiting resistors 561 to 564 for limiting the base current to the first column control terminal 577 of the microcomputer 581.
It is connected to the second column control terminal 578, the third column control terminal 579, and the fourth column control terminal 580.

Next, the operation will be described with reference to FIGS. 6 and 7. The LEDs on the matrix and the state of the mechanical switch are shown, and the LEDs at the positions 601 to 605 in FIG. 6 are turned on, and all the other LEDs are turned off. On the other hand, five mechanical switch positions 606 to 610 are conducting (hereinafter referred to as ON), and all other mechanical switches are cut off (hereinafter referred to as OFF).

When dynamic scan control is performed on the LED matrix and the mechanical switch matrix in the above-described state, a control signal is output to the column selected by each column control terminal as shown in FIG. For example, in the case of the first row, the LED row control terminals of the first row and the third row are set to “H” to turn on the LEDs at the positions 601 and 603 (both timings of periods T701 and T703 shown in FIG. 7). Is output, and a low level (hereinafter abbreviated as L) is output to the other LEDs. Similarly, regarding the mechanical switches in the first column, the input information from the mechanical switches at the positions 606 and 608 is "L" at the mechanical switch row control terminals of the first and third rows (in the periods T706 and T708 shown in FIG. 7). Both timings).

Similar to the above, the operations shown in FIGS. 6 and 7 are performed at other column control timings.

[0008]

However, in the conventional structure as described above, it is necessary to form a matrix of a plurality of LEDs and a plurality of mechanical switches respectively, and the row control terminal and the column control terminal from the microcomputer are provided. On the other hand, LEs that require a large number and consume a large amount of current
For D, it is necessary to provide transistors for driving on the row control terminals and the column control terminals for the number of constituent rows plus the number of constituent columns. Therefore, in designing the device, a microcomputer having a large number of input / output control lines must be used. There is a problem in that the number of mounted parts is increased due to the lack of a transistor and the necessity of a driving transistor.

The present invention has been made in view of the above problems, and an object thereof is to provide a composite switch module in which a light emitting display element and a mechanical switch are composited, and a highly reliable dynamic scan control circuit with a small number of parts. To do.

[0010]

In order to achieve the above object, in a composite switch module in which a light emitting display element and a mechanical switch are combined, either the operation of the driving means of the light emitting display element or the operation of the mechanical switch is effective. Selecting switch means having a first control terminal for making a selection, and obtaining a logical product output for controlling the light emitting display element to emit light when this selecting switch means enables the operation of the driving means of the light emitting display element. AND operation means having second and third control terminals, and when the selection switch means selects the operation of the mechanical switch to be effective, the output signal by the operation of the mechanical switch is the second or third control. It has an output means for outputting to any of the terminals. Further, it is a dynamic scan control circuit when a plurality of the composite switch modules are used and arranged in a matrix to form an operation display panel.

[0011]

The composite switch module and the dynamic scan control circuit using the same of the present invention having the above-described structure are switched by inputting a control switching signal to the first control terminal of the selection switch selection means, and are switched to LEDs or the like. The display control function of the light emitting display element and the control function of the mechanical switch are simultaneously realized. In particular, when display control of the light emitting display element is performed, logical product control is performed using the second and third control terminals, and control by mechanical switches is performed by the output means connected to the second and third control terminals. In that case, since the control output can be obtained from any one of the second and third control terminals, a highly reliable composite switch module having a simple structure and a dynamic scan control circuit using the same can be realized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A composite switch module according to an embodiment of the present invention and a dynamic scan control circuit using the same will be described below with reference to FIGS. 1 of FIG.
Reference numeral 0 is a composite switch module according to the present invention.

The anode of the LED 102 as a light emitting display element is connected to the power supply terminal 111, and the power supply terminal 111 is
It is connected to the power supply via a limiting resistor 116 outside the module that determines the drive current of the LED 102. Meanwhile LED
The cathode of 102 is connected to the collector of transistor 103. The base of the transistor 103 is connected to the row control input / output terminal 112 via the current limiting resistor 101 that limits the base current, and is externally biased to the power supply potential by the bias resistor 117. The emitter of the transistor 103 is connected to the collector of another transistor 104. The base of the transistor 104 is connected to the column control input terminal 11 via a current limiting resistor 105 that limits the base current.
Connect to 3. The emitter of the transistor 104 is connected to the collector of the transistor 107. The series circuit of the transistors 103 and 104 operates as a logical product calculating means having the row control input / output terminal 112 and the column control input terminal 113 as inputs.

The base of the transistor 107 is connected to the control switching input terminal 114 via the current limiting resistor 106 that limits the base current, and the emitter of the transistor 107 is connected to the ground terminal 115 and is grounded outside the module. The transistor 107 operates as a selection switch means according to a control signal input to the control switching input terminal 114.

One end of the mechanical switch 108 is connected to the row control input / output terminal 112, the other end is connected to the anode of the reverse bias prevention diode 109 with respect to the collector of the transistor 110, and its cathode is connected to the collector of the transistor 110. .. The base of the transistor 110 is connected to the base of the transistor 104 described above, and the current limiting resistor 105 is also used for limiting the base current. Also,
The emitter of the transistor 110 is connected to the control switching input terminal 114. This transistor 110 is configured as an output means for the operation of the mechanical switch 108, and an output signal appears at the row control input / output terminal 112. The row control input / output terminal 112, the column control input terminal 113, and the control switching terminal 114 are respectively the row control terminal 119 and the column control terminal 120 of the microcomputer 118 that controls the device.
And the control switching terminal 121, respectively.

The function of the reverse bias prevention diode 109 is that the emitter of the transistor 110 is at "H" level, the column control terminal 120 of the microcomputer 118 connected to the column control input terminal 113 is at "H" level, and the row is in the row. Row control terminal 119 to which the control input / output terminal 112 is connected
Is in the “L” level state, the mechanical switch 108 is ON.
In this case, the reverse transistor characteristic of the transistor 110 prevents a phenomenon in which an excessive current flows from the control switching terminal 121 of the microcomputer 118 to the row control terminal 119 via the emitter and collector of the transistor 110.

In the operation of the composite switch module configured as described above, when the LED 102 is turned on, the output level of the control switching terminal 121 is set to "H" and the transistor 107 is turned on. On the other hand, transistor 1
Since the emitter of 10 also becomes “H”, the transistor 110 can no longer be turned on regardless of the input level of the base, and the mechanical switch 108 connected to its collector is in the cut-off state. Next, when the column control terminal 120 outputs the level "H" in the column selected state, the transistor 104 is turned on. Next, when the row control terminal 119 for driving the LED outputs "H" level, the transistor 103 is turned on and the transistors 103, 104, 1
A current flows through the LED 102 via 07, and the LED 102 is turned on.

On the other hand, when inputting the ON / OFF state of the mechanical switch 108, the previous control switching terminal 121 is set to the "L" level and the previous LED drive transistor 107 is turned off. This transistor 107 is OF
When F, the transistor 104 connected to its collector
Also, since the emitter current of the transistor 103 stops flowing, the LED 102 does not light regardless of the base input level of these transistors. By the way, since the transistor 110 is in a grounded emitter state,
In the column selected state, the column control terminal 120 outputs the “H” level, so that the base current flows through the transistor 110 and the transistor 110 is saturated. In such a state, the microcomputer 118 needs to switch the terminal mode of the row control terminal 119 to the input mode inside the microcomputer 118 in advance. In this input mode, the bias resistor 117 works effectively, and when the mechanical switch 108 is in the OFF state, the row control terminal 119 is kept at the “H” level. At this time, if the mechanical switch 108 is pressed and is in the ON state, the collector output level “L” of the transistor 110 biases the reverse bias prevention diode 109 in the forward direction,
The "L" level is output on the row control terminal 119.

FIG. 2 shows a dynamic scan circuit in which the composite switch module 100 of FIG. 1 configured as described above is arranged in a matrix of 4 rows and 4 columns. Reference numerals 201 to 216 are equivalent to the composite switch module 100 described in FIG. Power supply terminal 1 of FIG. 1 of the composite switch module located in the same row
The terminals corresponding to 11 are connected to each other, and current limiting resistors 217 to 220 that limit the current that determines the brightness of the LED.
Are respectively connected to the power source via. Similarly, terminals corresponding to the row control input / output terminal 112 of FIG. 1 located in the same row are also connected to each other, and the first row row control terminal 225, the second row row control terminal 226 of the microcomputer 234 as a control means. The third row row control terminal 227 and the fourth row row control terminal 228 are respectively connected and configured as row control means. Then, to each row control terminal of the microcomputer 234, the bias resistors 221 to 224 for biasing the power supply potential are connected, respectively.

On the other hand, the terminals corresponding to the column control input terminals 120 in FIG. 1 of the composite switch module located in the same row are connected to each other, and the first of the microcomputer 234 is connected.
The column control unit 229, the second column control terminal 230, the third column control terminal 231, and the fourth column control terminal 232 are connected to each other to constitute a column control unit. Further, terminals corresponding to the control switching input terminals 121 of FIG. 1 of all the composite switch modules on the matrix are connected to each other,
Control switching terminal 233 of the microcomputer 234
Connected as a control switching means. Figure 1
All terminals corresponding to the ground terminal 115 of are also grounded.

The control will be described with reference to FIGS. 3 and 4. Positions 301 to 305 on the matrix of FIG. 3 indicate the portions where the LEDs are lit, and positions 306 to 310.
Indicates the part where the mechanical switch is ON. Turn on / off the mechanical switch by lighting the LED as described above.
Control for reading the state is performed from the period T401 to T shown in FIG.
The timing of 410 corresponds.

First, the first column is the first column control terminal 229.
When the control switching terminal 233 is at the “H” level, the LED control state is set and the row control terminals from the first row 225 to the fourth row 228 are internally set to the output mode state by the microcomputer 234. To be done. At this time, the first row row control terminal 2 which should turn on the LED
25 and the output of the third row row control terminal 227 are set to "H" level (corresponding to the periods T401 and T403 in FIG. 4), and the other rows are set to "L" level. Next, in order to input the state of the mechanical switch, the control switching terminal 233 is set to "L" level, and at the same time, the microcomputer 234 as a control means.
Internally sets all row control terminals to input mode.
In this case, the row where the mechanical switch is not turned on is pulled up to the power supply potential by the bias resistor, but the portion where the mechanical switch is turned on (periods T406 and T in FIG. 4).
(Corresponding to 408), "L" level appears.

As described above, the column control terminals 229 to 232
By switching the control switching terminal 233 and switching the input / output modes of the row control terminals 225 to 228, the LED lighting control and the mechanical switch information input can be performed at each column control timing. In addition, the transistor, reverse bias prevention diode, and LED of Fig. 1
The resistors and resistors can all be formed on the same silicon wafer. By doing so, not only the reliability of the circuit can be further improved, but also the cost for mass production can be improved. It is a clear fact that it will be a high performance configuration.

[0024]

As is apparent from the above description, the present invention provides a composite switch module in which a light emitting display element such as an LED and a mechanical switch are combined with a function of selecting driving of the light emitting display element and control of the mechanical switch. As a result, when a switch such as a button telephone and a display matrix circuit are formed by using this composite switch module, not only the connection with the microcomputer as the control body is simplified, but also a transistor for driving an LED, etc. There is an effect that it is possible to significantly reduce the number of parts of the device, simplify the circuit configuration, and significantly improve the reliability of the device, without separately preparing.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a composite switch module according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a dynamic scan control circuit using the composite switch module of the same embodiment.

FIG. 3 is a state diagram showing states of LEDs and mechanical switches on a dynamic scan control circuit of the same embodiment.

FIG. 4 is a timing chart showing control signals of each control terminal of the embodiment.

FIG. 5 is a circuit diagram showing a configuration example of a conventional dynamic scan control circuit.

FIG. 6 shows an L on the conventional dynamic scan control circuit.
State diagram showing the state of ED and mechanical switch

FIG. 7 is a timing chart showing a control signal of a control terminal of the conventional dynamic scan control circuit.

[Explanation of symbols]

 100 composite switch module 102 LED 103, 104, 107, 110 transistor 108 mechanical switch 109 reverse bias prevention diode 112 row control input / output terminal 113 column control input terminal 114 control switching terminal

Claims (2)

[Claims] 1. A light emitting display element, a mechanical switch, a driving means for causing the light emitting display element to emit light, and a first control terminal for selectively enabling operation of either the driving means or the mechanical switch. Select switch means having the second and second obtaining a logical product output for controlling the light emitting display device to emit light by the drive means when the operation of the drive means is selected by the select switch means Three
AND operation means having a control terminal of, and when the selection switch means selects the operation of the mechanical switch to be effective, the output signal due to the operation of the mechanical switch outputs the second and third output signals. A composite switch module having output means for outputting to any of the control terminals. 2. A plurality of composite switch modules according to claim 1, which are arranged in a matrix, control switching means to which respective first control terminals of the composite switch modules are connected together, and the composite switch module. Of the second and third control terminals of each column are collectively connected for each column, and the control terminals of the second and third control terminals which are not connected to the column control means are provided for each row. And a row control means connected collectively to the column control means and the row control means when the control switching means performs selection control for validating the operation of the driving means of the composite switch module. Lighting control of the light emitting display element is performed by control, and the operation of the mechanical switch of the composite switch module is enabled by the control switching means. When the selection control is performed, the control for obtaining the output signal by the operation of the mechanical switch at the control terminal connected to the row control means of the composite switch module of the corresponding column by the dynamic scan control by the column control means. Dynamic scan control circuit having means.