JPH0229244B2 - TATSUCHISHIKIDENSHIBORIUMUNIOKERUGODOSABOSHIKAIRO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a malfunction prevention circuit for a touch-type electronic volume that can perform position detection and operation detection simultaneously.

Generally, as a touch-type electronic volume circuit, there is known an electronic volume circuit that is provided with a level up switch and a level down switch, and operates so that the level changes only while either of the switches is pressed.

However, with such an electronic volume circuit, when using it to set the recording level of a tape recorder to record a signal such as music, the above-mentioned up switch must be pressed to adjust the level of the signal to the optimum recording level. Subsequently, the recording level is raised or lowered by continuing to press the down switch, but at this time it takes some time to reach the desired level.

As is well known, the signal level of the above-mentioned music, etc. changes from moment to moment during this period of time, and it is extremely difficult to match it to the above-mentioned optimum recording level.
Another drawback is that it takes a lot of time.

Conventionally, devices have been devised in which the above-mentioned drawbacks are eliminated and the desired level can be obtained by simply pressing the position of the desired level scale with a finger or the like. Hereinafter, a conventional example will be explained with reference to FIGS. 1, 2, and 3. In Figure 1, 1
is a potentiometer, and its structure is as shown in FIG. 2, in which a strip resistor 3 produced by well-known carbon vapor deposition is attached to a substrate 2 made of an insulator, and lead wires 4 are connected from both ends of the strip resistor 3. and 5
is connected. The strip-shaped conductor 6 is attached to the substrate 2 approximately parallel to the strip-shaped resistor 3, and the lead wire 7
have. The spacer 8 is the strip resistor 3
and a strip conductor 9 facing the strip conductor 6, respectively.
and the strip-shaped conductor 10 so as to maintain a space between them. Note that the band-shaped conductor 9 and the band-shaped conductor 10 have lead lines 11 and 12, respectively. Nameplate 13 is made of plastic film, etc.
A level scale 14 is provided on its surface, and the strip conductor 9 and strip conductor 10 are attached to the opposite side thereof and bonded to the substrate 2 via the spacer 8.

Potentiometer 1 configured in this way
When not pressed by a person's finger 15, an appropriate space is maintained between the strip resistor 3 and the strip conductor 9, and between the strip conductor 6 and the strip conductor 10 by the spacer 8, and the finger 15 When pressed by the press, the vicinity of the pressed part of the nameplate 13 deforms as shown in FIG.
and the strip conductor 6 and the strip conductor 10 are in contact at the same time,
When the pressing is stopped, the name plate 13 returns to its original state due to its elasticity and the contact is released.

Therefore, the resistance value between the leader wire 5 and the leader wire 11 changes depending on the portion pressed, and the leader wire 7 and the leader wire 12 are brought into a conductive state.

That is, the potentiometer 1 has inside thereof a volume VR whose internal resistance is varied by the pressure of a person's finger and which is involved in position detection, and a switch S which is involved in the detection of conduction operation.

16 is a well-known A/D conversion circuit, 17 is a well-known microcomputer circuit, 18 is a well-known electronic volume that divides the value of the signal SG using an analog switch and outputs the value 0, +B is the power supply voltage of the circuit. It is.

Now, when a person's finger 15 presses an arbitrary position on the level scale 14 attached to the potentiometer 1, almost at the same time as the switch S turns on, both ends of the VR are connected to the circuit. Since the power supply voltage +B is applied, the leader line 7, that is, A/
A voltage value obtained by dividing the power supply voltage +B of the circuit is applied to the D converter 16.

The microcomputer circuit 17 gives a conversion operation instruction to the A/D conversion circuit 16 only once after some time has passed after the switch S is turned on. The A/D conversion circuit 16 converts the divided voltage value into digital data only when receiving the instruction, and the microcomputer circuit 17 converts the divided voltage value into digital data.
to communicate. When the microcomputer circuit 17 finishes receiving the digital data, it drives the electronic volume 18 and holds the previous digital data until the next digital data is input. The electronic volume 18 divides the voltage of the signal SG according to the digital data and outputs the value 0.

Therefore, the output level 0 obtained by dividing the signal SG set by the electronic volume 18 corresponds to the level value indicated at the position of the level scale 14 pressed by the finger 15.

Therefore, the touch-type electronic volume circuit according to this conventional example can set a level proportional to the value of the pressing portion on the level scale attached to the potentiometer.

However, the operation of the conventional device described above is based on the assumption that the strip resistor 3 and the strip conductor 9, and the strip conductor 6 and the strip conductor 10 are brought into contact at the same time by pressing the finger 15. There is a possibility that the band-shaped conductors and the like do not contact each other at the same time. In particular, if the pair of band-shaped conductor 6 and band-shaped conductor 10 contacts the pair of band-shaped resistor 3 and band-shaped conductor 9 before contacting, or if only the pair of band-shaped conductor 6 and band-shaped conductor 10 contacts, the first
Even though the switch S shown in the figure is conducting, the volume is
A state in which VR is not conductive occurs, and position detection is not performed even though operation detection has been performed, resulting in new drawbacks as described below.

As mentioned above, the microcomputer circuit 1
7 gives an instruction to the A/D converter 16 to perform a conversion operation some time after the switch S is turned on, and only when this instruction is received does the A/D converter 16 start the conversion operation.
The D converter 16 converts the divided voltage value into digital data and transmits it to the microcomputer circuit 17.
When the pair of strip resistor 3 and strip conductor 9 come into contact with each other far in advance, or when only the pair of strip conductor 6 and strip conductor 10 comes into contact, the A/D converter 16 is in the operating state, but the above-mentioned divided voltage value is not input, and instead disturbance noise emitted from the finger 15, etc., power supply hum, etc. are input, and these are A/D converted and input to the electronic volume 18. There is a risk that the electronic volume 18 may malfunction.

The present invention has been made in order to eliminate the drawbacks of the conventional ones as described above, and the present invention
By adding a capacitor of appropriate capacity to the input side of the means for converting voltage values such as 6 to digital signals, position detection becomes unstable even when only operation detection is performed. Malfunction in touch type electronic volume control. The purpose is to provide a prevention circuit.

An embodiment of the present invention will be described below with reference to FIG. The circuit configuration is A/D as shown in Figure 1.
A capacitor C is newly connected in parallel to the input side of the conversion circuit 16, and the mechanical configuration is the same as that shown in FIGS. 2 and 3. This capacitor C has a power supply voltage +
It is charged by the divided voltage of B. Next, when the pressing is finished and a space is maintained between the volume VR and the input side of the A/D converter 16 (that is, between the strip resistor 3 and the strip conductor 9), the charged capacitor C is begins to discharge. The above A/D converter 16
If the input impedance of the capacitor C is high, the input side of the A/D converter 16 will have a certain voltage (approximately the divided voltage that initially charged the capacitor C) due to the above discharge.
Since it is held stably for quite a long time, if you firmly press the potentiometer 1 with your finger 15 and it operates normally, the next time you press it with your finger, only operation detection will work. Since a certain amount of voltage is supplied to the electronic volume 18 and the volume is set at a certain arbitrary position, malfunction of the electronic volume 18 is prevented.

As mentioned above, this article describes a potentiometer 1 that can detect position and operation at the same time by disposing a strip conductor or a strip resistor in one container, and the resistance value of the output terminal of the potentiometer 1. Means (A/D conversion circuit 1
6), a touch-type electronic volume comprising means for storing the digital signal (microcomputer circuit 17), and means for changing internal resistance according to the digital signal (electronic volume 18), the voltage value is digitally stored. Since a capacitor C of an appropriate capacity is added to the input side of the means for converting into a signal (A/D conversion circuit 16), once the potentiometer 1 is firmly pressed with a finger 15, it will operate normally. Even if only the operation detection operates when you press it next time with your finger, the above electronic volume 18
Since a certain amount of voltage is supplied to and the volume is set at an arbitrary position, the electronic volume 1
8 malfunction is prevented and stable operation is obtained.

[Brief explanation of drawings]

Figure 1 is a block diagram showing a conventional example of a touch-type volume circuit, Figure 2 is an exploded perspective view showing the configuration of a potentiometer, and Figure 3 shows a person's finger pressing the potentiometer. FIG. 4, a partial cross-sectional view, is a block diagram showing one embodiment of the present invention. 1... Potentiometer, 16... A/D
Conversion circuit, 17...Microcomputer circuit, 18...Electronic volume, C...Capacitor.

Claims (1)

[Claims] 1 A potentiometer that can detect position and operation at the same time by arranging a strip conductor or a strip resistor in one device, and replacing the change in resistance value of the output terminal of the potentiometer due to level setting with a voltage value. Then, in a touch-type electronic volume equipped with means for converting the voltage value into a digital signal, means for storing the digital signal, and means for internally changing resistance according to the digital signal, the voltage value is converted into a digital signal. A malfunction prevention circuit for a touch-type electronic volume, characterized in that a capacitor of an appropriate capacity is added to the input side of the means for converting the voltage.