JP2011023252A - Input circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an input circuit which is easy to carry out the input operation, while suppressing increase in power consumption and increase in the number of resistive elements. <P>SOLUTION: The input circuit 100 includes a first circuit part 10 having resistive elements 11, 12, 13; a second circuit part 20, arranged in parallel to the first circuit part 10 and having resistive elements 21, 22; a plurality of switches 30a-30i which can individually form a plurality of mutually different electric pathways from a power supply 110 to a ground 120, by connecting nodes N1-N3 of the first circuit part 10 and nodes N4-N6 of the second circuit part 20, and respectively go into non-connecting states in normal state; and an output terminal 40 for outputting a voltage divided by the resistive element of the first circuit part 10 and the resistive element of the second circuit part 20, corresponding to a predetermined electric pathway, when a predetermined electric pathway is formed by connecting one switch out of the plurality of switches. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an input circuit, and more particularly to an input circuit having a plurality of switches.

  Conventionally, an input circuit including a plurality of switches is known (see, for example, Patent Documents 1 to 3).

  Patent Document 1 discloses an input circuit in which five resistance elements, a first resistance element to a fifth resistance element, are connected in series from a power supply side between a power supply and a ground (ground terminal). An output terminal for outputting a divided voltage is provided between the third resistance element and the fourth resistance element of the input circuit. The input circuit includes a first switch connected in parallel to the first resistance element and the second resistance element, a second switch connected in parallel to the second resistance element and the third resistance element, A third switch connected in parallel to the fourth resistance element is provided. This input circuit combines the first to third switches when all of the first to third switches are turned off (one way), when the first to third switches are turned on separately (three ways). In this case, the voltage at the output terminal is different from each other when the first switch is turned on (three ways) and when all the first to third switches are turned on (one way). Thereby, the input circuit according to Patent Document 1 is configured to be able to obtain a total of eight different output voltages depending on the combination of the five resistance elements and the three switches.

  Further, in Patent Document 2, a first switch unit including a first movable contact that is selectively connected to four first resistance elements connected in series between a power source and a ground (ground terminal), and 4 There is disclosed an input circuit including a second switch portion including a second movable contact that is selectively connected to two second resistance elements. The first movable contact of the first switch unit is selectively connected to one of the terminals of the four first resistance elements by sliding the first switch unit. That is, one first movable contact is provided so that it can be used in common for the four first resistance elements. For this reason, the four voltages divided by one or more of the four first resistance elements are applied to the first movable contact by switching the connection position. The four second resistance elements of the second switch unit are configured to receive the voltage applied to the first movable contact. The second movable contact of the second switch unit is selectively connected to any one of the power supply side terminals of the four second resistance elements by sliding the second switch unit. That is, one second movable contact is provided so that it can be used in common for the four second resistance elements. For this reason, the four voltages divided by one or more of the four second resistance elements are applied to the second movable contact by switching the connection position. As a result, a combination of the position (four ways) of the first movable contact of the first switch part and the position (four ways) of the second movable contact of the second switch part is combined (four first movements of the first switch part). Contact connection position) × 4 ways (connection position of the second movable contact of the second switch part) = 16 kinds of voltages are output from the second movable contact of the second switch part.

  Further, in Patent Document 3, five resistance elements connected in series between a power supply and a ground (ground terminal), five switches connected to the power supply side terminal of each resistance element, and five switches, respectively. And an input circuit having a voltage detection circuit connected in common. When any one of the five switches is connected, the voltage divided by one or a plurality of resistance elements according to the connection position of the switch is input to the voltage detection circuit. In other words, in the input circuit disclosed in Patent Document 3, a switch is provided for each of the five resistance elements connected in series, and the five voltages are supplied to the voltage detection circuit by changing the extraction position of the voltage divided by the resistance elements. It is configured to output.

Japanese Patent Laid-Open No. 10-12080 Japanese Utility Model Publication No. 5-4240 Japanese Patent Laid-Open No. 9-45171

  However, in the input circuit disclosed in Patent Document 1, it is possible to output eight kinds of voltages using five resistance elements by a combination of on / off of three switches. Even if the 3 switch is in an on / off state, an electric path from the power source to the ground is formed, so that a current continues to flow through the input circuit. For this reason, there exists a problem that power consumption will increase. Further, since the output voltage output from the output terminal is changed depending on the combination of ON / OFF of the three switches, in order to obtain a desired output voltage, each of the ON / OFF of the three switches becomes a predetermined combination. It is necessary to switch each switch. For this reason, in order to perform an operation input for outputting a desired output voltage, a maximum of three input operations (operations for turning on or off the switch) are required, and there is a problem that the input operation is complicated.

  The input circuit disclosed in Patent Document 2 uses a total of eight resistance elements by combining four variable first and second switch portions (first movable contact and second movable contact). 16 voltages can be output, while the first movable contact of the first switch part and the second movable contact of the second switch part are in any connection position from the power source to the ground. In this state, current continues to flow through the input circuit. For this reason, there exists a problem that power consumption will increase. Further, since the output voltage is changed depending on the combination of the connection position of the first movable contact of the first switch section and the connection position of the second movable contact of the second switch section, two switches are used to obtain a desired output voltage. It is necessary to perform the switching operation of each of the two switch units so that the connection positions of the movable contacts of the unit become a predetermined combination. For this reason, in order to perform an operation input for outputting a desired output voltage, a maximum of two input operations are required, and there is a problem that the input operation is complicated.

  Further, in the input circuit disclosed in Patent Document 3, it is possible to output five kinds of voltages using five resistance elements by putting any of the five switches in a connected state. Even when all the two switches are turned off (disconnected state), an electric path from the power supply to the ground is formed, so that current continues to flow through the input circuit. For this reason, there exists a problem that power consumption will increase. Further, since switches are provided at the power supply side terminals of the five resistance elements and the extraction positions of the voltages divided by the resistance elements are changed, it is only possible to provide the same number of switches as the number of resistance elements. For this reason, there is a problem that the number of resistance elements increases by the number of switches required for the input circuit.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an input circuit that allows easy input operation while suppressing an increase in power consumption and an increase in the number of resistance elements. Is to provide.

Means for Solving the Problems and Effects of the Invention

  An input circuit according to one aspect of the present invention is connected to a power source, includes a first circuit unit including at least one resistance element, and at least one connected in parallel to the first circuit unit and connected to a ground terminal. From the power source by connecting the second circuit part including one resistance element, one of the one terminal and the other terminal of the resistance element of the first circuit part, and one of the one terminal and the other terminal of the resistance element of the second circuit part A plurality of different electrical paths leading to the ground terminal can be individually formed, and each is arranged on a path from the power source to the ground terminal, with a plurality of switches configured to be in a disconnected state in the normal state. When a predetermined electrical path is formed by connecting one of the plurality of switches, the resistance element of the first circuit unit and the resistance element of the second circuit unit corresponding to the predetermined electrical path And an output terminal for outputting a more divided voltage.

  In the input circuit according to one aspect of the present invention, as described above, the first circuit unit connected to the power source and including at least one resistance element is provided in parallel to the first circuit unit, and is connected to the ground terminal. A second circuit portion including at least one resistance element to be connected, and one of one terminal and the other terminal of the resistance element of the first circuit portion and one of the one terminal and the other terminal of the resistance element of the second circuit portion And a plurality of different electrical paths from the power source to the ground terminal are individually formed by a plurality of switches. By configuring in this way, when any one of the plurality of switches is connected, the resistance element disposed on the power supply side with respect to the switch connection position in the first circuit unit, and the first circuit In the second circuit part provided in parallel with the part, a predetermined electric path passing through the resistance element arranged on the ground side from the connection position of the switch is individually formed. As a result, in the entire input circuit, the number of resistance elements for dividing the power supply voltage and the combination of the resistance elements can be made different by setting any one of the switches to the connected state. Accordingly, even when the number of resistance elements is small, by appropriately setting the combination of resistance values of the resistance elements, it is possible to output voltages (divided voltages) of many patterns by combining these resistance elements. In addition, since one electrical path different from each other is determined by setting one switch to a connected state (on state), an input operation is facilitated by not combining a plurality of switches on / off. Further, by configuring each of the plurality of switches so as to be disconnected in the normal state, the first circuit unit and the second circuit unit individually connected by the plurality of switches are electrically connected in the normal state. There is no connection. As a result, since current flows only when the switch is connected, it is possible to suppress an increase in power consumption.

  In the input circuit according to the one aspect described above, preferably, each of the plurality of switches includes a set of fixed contacts and a movable contact, and is connected by connecting each set of the movable contacts to the corresponding fixed contact. When the predetermined electrical path is formed by connecting the movable contact of one of the plurality of individual switches to the corresponding fixed contact, the predetermined electrical path is formed. A voltage corresponding to one individual switch is output from the output terminal by dividing the voltage of the power supply by the respective resistance elements of the first circuit unit and the second circuit unit corresponding to the path. Yes. With this configuration, it is possible to easily determine which individual switch is turned on (connected state) by detecting the voltage of the output terminal.

  In the configuration in which each of the plurality of switches is an individual switch, preferably, the individual switch includes a push-down switch. If comprised in this way, it will be comprised so that it may be in a connection state by connecting each set of movable contact to a corresponding fixed contact while it contains a set of fixed contacts and a movable contact, and it is not in a normal state. An individual switch configured to be in a connected state can be easily configured.

  In the input circuit according to the above aspect, the resistance element preferably includes a first resistance element provided on the power supply side with respect to the output terminal, and a second resistance element provided on the ground terminal side with respect to the output terminal. Each of the switches connected to each other by changing the combination of the second resistance elements arranged on the electric path formed individually by connecting each of the plurality of switches. The combined resistance values of the second resistance elements arranged on the electrical path are different from each other. If comprised in this way, the synthetic resistance value by the side of a grounding terminal can be changed with respect to an output terminal for every electric path formed by each of a plurality of switches. When any one switch forms an electrical path in which the first resistance element and the second resistance element are connected from the power supply side to the ground side, the output voltage from the output terminal is equal to the resistance value of the first resistance element and the first resistance value. It is determined by the ratio with the combined resistance value of each second resistance element of the circuit unit and the second circuit unit. As a result, by changing the combined resistance value on the ground terminal side with respect to the output terminal, a voltage having a different magnitude is output from the output terminal for each of the plurality of switches. Can be determined individually.

  In the input circuit according to the above aspect, the resistance element preferably includes a first resistance element provided on the power supply side with respect to the output terminal, and a second resistance element provided on the ground terminal side with respect to the output terminal. The one terminal and the other terminal of all the second resistance elements of the first circuit portion are individually connected to the one terminal and the other terminal of all the second resistance elements of the second circuit portion by a plurality of switches, respectively. It is configured to be connectable. If comprised in this way, all the combinations which can be combined with the 2nd resistive element of the 1st circuit part and the 2nd resistive element of the 2nd circuit part are made into each electric path connected individually by a plurality of switches. It can be configured by switching. Thereby, it is possible to easily output a large number of patterns of voltage (divided voltage) with a small number of resistance elements.

  In the configuration in which the resistance element includes the first resistance element and the second resistance element, preferably, the first circuit portion and the second circuit portion each include a plurality of second resistance elements, and the second resistance of the first circuit portion. The difference between the number of elements and the number of second resistance elements of the second circuit unit is 0 or 1. If comprised in this way, compared with the case where the difference of the number of the 2nd resistive elements of a 1st circuit part and the number of the 2nd resistive elements of a 2nd circuit part is larger than 2, one terminal of each 2nd resistive element In addition, the number of combinations of the second resistance elements that can be arranged on the electric path formed by individually connecting the other terminals one by one can be increased. Thus, by appropriately setting the resistance value of each second resistance element, it is possible to output different voltages from the output terminal depending on the combination of the second resistance elements arranged on the electrical path. That is, the number of switches that can be determined by outputting different voltages from the output terminals can be increased.

  In the input circuit according to the one aspect, preferably, the switch is connected to the output terminal and, based on the magnitude of the voltage output from the output terminal, which of the plurality of switches is connected. The determination part is further provided. According to this configuration, when the plurality of switches are configured to output different voltages from the output terminal according to the above configuration, which switch is turned on (connected). Can be easily determined by the determination unit.

1 is a circuit diagram illustrating an input circuit according to a first embodiment of the present invention. 2 is a table showing a relationship between each switch of the input circuit shown in FIG. 1 and an output voltage. FIG. 6 is a circuit diagram illustrating an input circuit according to a second embodiment of the present invention. 4 is a table showing a relationship between each switch of the input circuit shown in FIG. 3 and an output voltage. It is the circuit diagram which showed the input circuit by the modification of 1st Embodiment of this invention. It is the circuit diagram which showed the input circuit by the modification of 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the configuration of the input circuit 100 according to the first embodiment of the present invention will be described with reference to FIG. 1 and FIG. In the first embodiment, the input circuit 100 of the present invention is provided with various operation keys (power button, volume adjustment key, channel operation key, recording key, playback key, etc.) provided in the operation unit of a DVD recorder or a digital television receiver, for example. A description will be given of an example applied to an input circuit that receives the input of).

  As shown in FIG. 1, the input circuit 100 according to the first embodiment of the present invention includes a first circuit unit 10 (see the broken line portion), a second circuit unit 20 (see the broken line portion), the first circuit unit 10, and Nine switches 30a to 30i that connect the second circuit unit 20 and an output terminal 40 that outputs nine different voltages corresponding to the switches 30a to 30i are provided. A power supply 110 is connected to the first circuit unit 10. The second circuit unit 20 is connected to a ground (ground terminal) 120. The output terminal 40 is connected to a predetermined input port of a microcomputer 50 such as a DVD recorder or a digital television receiver. In the first embodiment, a microcomputer (microcomputer) determines which of the nine switches 30a to 30i is turned on based on the magnitudes of nine different voltages output from the output terminal 40. 50) can be determined. In the first embodiment, by using these switches 30a to 30i in association with various operation keys provided in the operation unit of a DVD recorder or a digital television receiver, the microcomputer 50 side inputs a user operation key (switches 30a to 30a). 30i on and off). The power source 110 is connected to the end of the first circuit unit 10. The power supply 110 is configured to input a predetermined voltage V0 to the input circuit 100. In the first embodiment, the power supply 110 will be described as a constant voltage source with V0 = 3.3 [V]. The ground (ground terminal) 120 is an example of the “ground terminal” in the present invention. The microcomputer 50 is an example of the “determination unit” in the present invention.

  The first circuit unit 10 includes three resistance elements 11, 12 and 13. The resistance elements 11 to 13 of the first circuit unit 10 are connected in series in the order of the resistance elements 11, 12 and 13 from the power supply 110 side. That is, one terminal 11a of the resistance element 11 is connected to the power supply 110, and the other terminal 11b of the resistance element 11 is connected to the one terminal 12a of the resistance element 12 via the node N1. The other terminal 12b of the resistance element 12 is connected to one terminal 13a of the resistance element 13 via the node N2. The other terminal 13b of the resistance element 13 is connected to the node N3. In the first embodiment, the resistance values of the resistance element 11, the resistance element 12, and the resistance element 13 are R0 (about 10 kΩ), R3 (about 4 kΩ), and R4 (about 4 kΩ), respectively. An output terminal 40 is connected to a node N1 between the other terminal 11b of the resistance element 11 and one terminal 12a of the resistance element 12. The nodes N1 to N3 are connected to three of the switches 30a to 30i, respectively. Specifically, the node N1 is connected to the switches 30a, 30b, and 30g. Node N2 is connected to switches 30c, 30d and 30h. Node N3 is connected to switches 30e, 30f and 30i. The resistance element 11 is an example of the “first resistance element” in the present invention. The resistance elements 12 and 13 are examples of the “second resistance element” in the present invention. The switches 30a to 30i are examples of the “individual switch” and the “push-down switch” of the present invention, respectively.

  The second circuit unit 20 is provided in parallel to the first circuit unit 10 and includes two resistance elements 21 and 22. The resistance elements 21 and 22 are connected in series to the ground (ground terminal) 120. That is, one terminal 21a of the resistance element 21 is connected to the node N6, and the other terminal 21b of the resistance element 21 is connected to the one terminal 22a of the resistance element 22 via the node N5. The other terminal 22b of the resistive element 22 is connected to the ground (ground terminal) 120 via the node N4. In the first embodiment, the resistance values of the resistance element 21 and the resistance element 22 are R1 (about 12 kΩ) and R2 (about 2 kΩ), respectively. The nodes N4 to N6 are connected to three of the switches 30a to 30i, respectively. Specifically, the node N4 is connected to the switches 30a, 30c, and 30e. The node N5 is connected to the switches 30b, 30d, and 30f. Node N6 is connected to switches 30g, 30h and 30i. The resistance elements 21 and 22 are examples of the “second resistance element” in the present invention.

  In the first embodiment, the number of resistance elements (resistance elements 12 and 13) provided on the ground 120 side with respect to the output terminal 40 of the first circuit section 10 and the resistance elements 21 and 22 of the second circuit section 20 are described. The difference from the number of is configured to be zero.

  Each of the nine switches 30a to 30i includes a set of fixed contacts and a movable contact, and is configured to be connected by connecting each set of the movable contacts to the corresponding fixed contact. Each of the switches 30a to 30i individually connects one of all the nodes N1 to N3 of the first circuit unit 10 and one of all the nodes N4 to N6 of the second circuit unit 20 respectively. It is connected. Each of the switches 30a to 30i is a push-down switch (so-called a contact) configured to be in a disconnected state in a normal state. That is, only when one of the switches 30a to 30i is pressed by the user, the pressed switch (any one of 30a to 30i) electrically connects the first circuit unit 10 and the second circuit unit 20 to each other. Configured to connect to. For this reason, the input circuit 100 is configured such that an electric path from the power supply 110 to the ground 120 is formed only when there is an input from the user (switch depression).

  Each of the switches 30a to 30i individually connects one of the nodes N1 to N3 of the first circuit unit 10 and one of the nodes N4 to N6 of the second circuit unit 20, respectively. Different electric paths from the power source 110 to the ground 120 can be individually formed. At this time, one of the one terminal (12a or 13a) and the other terminal (11b, 12b or 13b) of the resistance element (11, 12 or 13) connected to the nodes N1 to N3 and the nodes N4 to N6 are connected. One terminal (21a or 22a) and one of the other terminals (21b or 22b) of the resistance element (21 or 22) are connected by a switch (any one of 30a to 30i). That is, when any one of the nine switches 30a to 30i is connected (on state), the connection positions of the switches 30a to 30i (any one of the nodes N1 to N3) in the first circuit unit 10. Further, the resistor elements (11, 12 and 13) arranged on the power supply 110 side and the connection positions of the switches 30a to 30i (any one of the nodes N4 to N6) in the second circuit unit 20 are arranged on the ground 120 side. An electrical path is formed through the resistive elements (21, 22).

  With such a configuration, when any of the plurality of switches 30a to 30i is pushed down and the first circuit unit 10 and the second circuit unit 20 are connected, they are arranged on an electric path from the power source 110 to the ground 120. The combination of the resistance elements 12, 13, 21, and 22 to be performed is changed. That is, when the electrical path is formed, the power supply 110 is formed by the combination of the resistance element 11 on the power supply 110 side with respect to the output terminal 40 and the resistance elements 12, 13, 21, and 22 on the ground 120 side with respect to the output terminal 40. Is divided. As a result, a voltage having a magnitude corresponding to the ratio between the resistance value R 0 of the resistance element 11 and the combined resistance value of the resistance elements 12, 13, 21 and 22 on the ground 120 side is output from the output terminal 40. It is configured. Here, even when any of the switches 30a to 30i is depressed, the resistance value R0 of the resistance element 11 on the power supply 110 side is not changed, so that the output voltage from the output terminal 40 is on each connected electric path. It is determined by a combined resistance value Rx by a combination of the arranged resistance elements 12, 13, 21, and 22 (resistance elements on the ground 120 side with respect to the output terminal 40). That is, the voltage output from the output terminal 40 to the microcomputer 50 is RxV0 / (R0 + Rx). In the first embodiment, when the input circuit 100 presses any of the switches 30a to 30i, the resistance elements 12, 13, 21 and 22 (output terminals) arranged on the respective electric paths to be connected are provided. 40, the combined resistance values Rx by the combination of the resistance elements on the ground 120 side with respect to 40 are different from each other. In this way, by detecting the output voltage of the output terminal 40 on the microcomputer 50 side, it is possible to determine which switch 30a to 30i has been pushed down.

  Further, as shown in FIG. 1, the output terminal 40 is electrically connected to the fixed contact corresponding to the movable contact of one of the nine switches 30 a to 30 i (any one of 30 a to 30 i). When the path is formed, it is separated by a combination of the resistance element 11 on the power supply 110 side with respect to the output terminal 40 and the resistance elements 12, 13, 21, and 22 on the electrical path on the ground 120 side with respect to the output terminal 40. The compressed voltage of the power supply 110 is output to the microcomputer 50.

  The microcomputer 50 is configured to determine which of the nine switches 30a to 30i is pressed based on the magnitude of the voltage output from the output terminal 40. For example, when the voltage output from the output terminal 40 is about 1.24 [V], the microcomputer 50 determines that the switch 30d is pressed down. In this way, the microcomputer 50 determines which of the operation keys (power button, volume control key, channel operation key, recording key, playback key, etc.) associated with each of the switches 30a to 30i has been pressed. It is possible.

  Next, the operation of the input circuit 100 according to the first embodiment of the present invention will be described with reference to FIG. 1 and FIG.

  As shown in FIG. 1, by turning on the switch 30a, the node N1 of the first circuit unit 10 and the node N4 of the second circuit unit 20 are connected, and the output terminal 40 is connected to the ground 120. Thereby, as shown in FIG. 2, the voltage (voltage output from the output terminal 40) detected by the input port of the microcomputer 50 becomes about 0 [V].

  Further, by turning on the switch 30b, the node N1 of the first circuit unit 10 and the node N5 of the second circuit unit 20 are connected, and an electric path passing through the resistance elements 11 and 22 is formed in the input circuit 100. The At this time, the resistance value of the electrical path (resistive element 22) on the ground 120 side with respect to the output terminal 40 is R2 = about 2 kΩ. As a result, the voltage detected by the input port of the microcomputer 50 (voltage output from the output terminal 40) is about 0.55 [V].

  Also, by turning on the switch 30c, the node N2 of the first circuit unit 10 and the node N4 of the second circuit unit 20 are connected, and an electric path passing through the resistance elements 11 and 12 is formed in the input circuit 100. The At this time, the resistance value of the electrical path (resistive element 12) on the ground 120 side with respect to the output terminal 40 is R3 = about 4 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 0.94 [V].

  Further, by turning on the switch 30d, the node N2 of the first circuit unit 10 and the node N5 of the second circuit unit 20 are connected, and an electric path passing through the resistance elements 11, 12, and 22 is connected to the input circuit 100. It is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R2 + R3 = about 6 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 1.24 [V].

  Also, by turning on the switch 30e, the node N3 of the first circuit unit 10 and the node N4 of the second circuit unit 20 are connected, and an electric path passing through the resistance elements 11, 12, and 13 is connected to the input circuit 100. It is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R3 + R4 = about 8 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 1.47 [V].

  Further, by turning on the switch 30f, the node N3 of the first circuit unit 10 and the node N5 of the second circuit unit 20 are connected, and the electric current passing through the resistance elements 11, 12, 13, and 22 is connected to the input circuit 100. A path is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R2 + R3 + R4 = about 10 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 1.65 [V].

  Further, by turning on the switch 30g, the node N1 of the first circuit unit 10 and the node N6 of the second circuit unit 20 are connected, and an electric path passing through the resistance elements 11, 21, and 22 is connected to the input circuit 100. It is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R1 + R2 = about 14 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 1.93 [V].

  Further, by turning on the switch 30h, the node N2 of the first circuit unit 10 and the node N6 of the second circuit unit 20 are connected, and the electric current passing through the resistance elements 11, 12, 21, and 22 to the input circuit 100 A path is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R1 + R2 + R3 = about 18 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 2.12 [V].

  Further, by turning on the switch 30i, the node N3 of the first circuit unit 10 and the node N6 of the second circuit unit 20 are connected, and all the resistive elements 11, 12, 13, 21, and 21 are connected to the input circuit 100. An electrical path through 22 is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R1 + R2 + R3 + R4 = about 22 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 2.27 [V].

  In the state where none of the switches 30a to 30i is pressed down (off state), the first circuit unit 10 and the second circuit unit 20 are not electrically connected, so the voltage output from the output terminal 40 is It becomes V0 (about 3.3 [V]) which is the same as the voltage of the power supply 110. Thus, in the first embodiment, one switch that is pressed down by changing the combination of the resistance elements 11, 12, 21, and 22 arranged on the electric path by each of the switches 30a to 30i. A voltage having a magnitude corresponding to 30 a to 30 i is output from the output terminal 40.

  In the first embodiment, as described above, the first circuit unit 10 that is connected to the power source 110 and includes the three resistance elements 11, 12, and 13 is provided in parallel with the first circuit unit 10. The second circuit section 20 including two resistance elements 21 and 22 connected to the (ground terminal) 120 is provided, and the resistance elements 11, 12, and 13 of the first circuit section 10 are provided by nine switches 30a to 30i. 9 different electrical paths are individually connected to each other by respectively connecting nodes N1 to N3 respectively connecting nodes N1 to N6 respectively connecting resistance elements 21 and 22 of the second circuit section 20 respectively. To form. With this configuration, when any one of the nine switches 30a to 30i is connected (on state), the connection position (node N1) of the switches 30a to 30i in the first circuit unit 10 To any one of N3) and the connection position of the switches 30a to 30i in the second circuit unit 20 provided in parallel to the first circuit unit 10 (nodes N4 to N4). An electrical path that passes through the resistance element disposed on the ground 120 side with respect to any one of N6) is formed. As a result, the input circuit 100 as a whole has the number of resistance elements (12, 13, 21, and 22) for dividing the voltage of the power supply 110 by connecting any one of the switches 30a to 30i, and the resistance elements. The combination of (12, 13, 21, and 22) can be different. Accordingly, even when the number of resistance elements is small, by appropriately setting the combination of the resistance values R0 to R4 of the resistance elements (12, 13, 21, and 22), these resistance elements (12, 13, 21, and 22) can be set. In combination, many patterns of voltage (divided voltage) can be output. Also, since one electrical path different from each other is determined by turning on one of the switches 30a to 30i, an input operation is facilitated by not combining a plurality of switches on / off. Further, by configuring each of the switches 30a to 30i to be in a disconnected state in a normal state, the first circuit unit 10 and the second circuit unit 20 connected by the plurality of switches 30a to 30i are in a normal state. Then there is no electrical connection. As a result, since current flows only when the switches 30a to 30i are connected, it is possible to suppress an increase in power consumption.

  In the first embodiment, as described above, the movable contact of one of the nine switches 30a to 30i (any one of 30a to 30i) is connected to the corresponding fixed contact, thereby causing an electrical path. Is formed by dividing the voltage V0 of the power supply 110 by the respective resistance elements 12 to 22 of the first circuit unit 10 and the second circuit unit 20 corresponding to the electric path to be formed. By configuring so that a voltage corresponding to one switch (any one of 30a to 30i) is output from the output terminal 40, by detecting the voltage of the output terminal 40, which switch (30a to 30i) It is possible to easily determine whether any of them is turned on (connected state).

  In the first embodiment, as described above, the switches 30a to 30i are formed of push-down switches, thereby including a set of fixed contacts and movable contacts, and each set of movable contacts corresponding to a fixed contact. It is possible to easily configure the switches 30a to 30i that are configured to be in a connected state by being connected to each other and configured to be in a non-connected state in a normal state.

  Moreover, in 1st Embodiment, a connection state is changed by changing each combination of the resistive element (12, 13, 21, and 22) arrange | positioned on the electrical path | route connected by each of nine switches 30a-30i. For each of the switches 30a to 30i, the combined resistance values of the resistance elements (12, 13, 21 and 22) arranged on the respective electric paths to be connected are different from each other, thereby providing nine The combined resistance value of the electrical path on the ground 120 side with respect to the output terminal 40 can be changed according to each of the switches 30a to 30i. When an electrical path in which the resistance element 11 and the resistance elements (12, 13, 21, and 22) are connected from the power supply 110 side to the ground 120 side by any one of the switches 30a to 30i is output from the output terminal 40 The voltage is determined by the ratio between the resistance value R0 of the resistance element 11 and the combined resistance value of the resistance elements (12, 13, 21, and 22). As a result, each of the nine switches 30a to 30i can be individually determined based on the fact that voltages of different magnitudes are output from the output terminal 40 for each of the nine switches 30a to 30i.

  In the first embodiment, as described above, the nodes N1 to N3 of the resistance elements 12 and 13 of the first circuit unit 10 are replaced with the nodes N4 to N4 of all the resistance elements 21 and 22 of the second circuit unit 20, respectively. By connecting N6 individually by nine switches 30a to 30i, all of the combinations of the resistance elements 12 and 13 of the first circuit unit 10 and the resistance elements 21 and 22 of the second circuit unit 20 are possible. These combinations can be configured by switching electrical paths respectively connected by the nine switches 30a to 30i. Thereby, it is possible to easily output a large number of patterns of voltage (divided voltage) with a small number of resistance elements (12, 13, 21, and 22).

  In the first embodiment, the number (two) of resistance elements (12 and 13) arranged on the ground 120 side with respect to the output terminal 40 of the first circuit unit 10 and the output terminal of the second circuit unit 20 With respect to the output terminal 40 of the first circuit unit 10, the difference from the number (two) of the resistance elements (21 and 22) arranged on the ground 120 side with respect to 40 is zero. Each node N1 is compared with a case where the difference between the number of resistance elements arranged on the ground 120 side and the number of resistance elements arranged on the ground 120 side with respect to the output terminal 40 of the second circuit unit 20 is larger than two. It is possible to increase the number of combinations (9 types) of resistance elements (12, 13, 21, and 22) that can be arranged on the electrical path formed by individually connecting N6 to N6 individually. Accordingly, the resistance value of each resistance element (12, 13, 21, and 22) is appropriately set, and thus varies depending on the combination of the resistance elements (12, 13, 21, and 22) arranged on the electric path. A voltage having a magnitude can be output from the output terminal 40. That is, the number (9) of switches 30a to 30i that can be determined by outputting different voltages from the output terminal 40 can be increased.

  Moreover, in 1st Embodiment, while being connected to the output terminal 40, based on the magnitude | size of the voltage output from the output terminal 40, any switch (30a-30i) of nine switches 30a-30i. By providing the microcomputer 50 that determines whether or not the connection state is established, each of the nine switches 30a to 30i outputs a voltage having a different magnitude from the output terminal 40. It can be easily determined by the microcomputer 50 whether 30a to 30i) are turned on (connected).

(Second Embodiment)
Next, an input circuit 200 according to a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the first embodiment is configured to output output voltages respectively corresponding to the nine switches 30a to 30i using a total of five resistance elements (11 to 13, 21 and 22). Differently, an example will be described in which a total of six resistance elements (11, 212 to 214, 221 and 222) are used to output output voltages respectively corresponding to 12 switches 230a to 230l.

  In the second embodiment, as shown in FIG. 3, the first circuit portion 210 (see the broken line portion) of the input circuit 200 includes one resistive element 11 provided on the power supply 110 side with respect to the output terminal 40 and an output. Three resistance elements 212, 213, and 214 provided on the ground 120 side with respect to the terminal 40 are included. The three resistance elements 212, 213 and 214 on the ground 120 side are connected in series in the order of the resistance elements 212, 213 and 214 from the power supply 110 side. That is, one terminal 11a of the resistive element 11 is connected to the power source 110, and the other terminal 11b of the resistive element 11 is connected to one terminal 212a of the resistive element 212 via the node N11. The other terminal 212b of the resistance element 212 is connected to one terminal 213a of the resistance element 213 via the node N12. The other terminal 213b of the resistance element 213 is connected to one terminal 214a of the resistance element 214 via the node N13. The other terminal 214b of the resistance element 214 is connected to the node N14. In the second embodiment, the resistance values of the resistance elements 212, 213, and 214 are R7 (about 5 kΩ), R8 (about 5 kΩ), and R9 (about 5 kΩ), respectively. A node N11 on the power supply 110 side of the resistance element 212 is connected to the switches 230a, 230b, and 230i. The node N12 is connected to the switches 230c, 230d, and 230j. The node N13 is connected to the switches 230e, 230f, and 230k. The node N14 is connected to the switches 230g, 230h, and 230l. The resistance elements 212, 213, and 214 are examples of the “second resistance element” in the present invention. The switches 230a to 230l are examples of the “individual switch” and the “push-down switch” of the present invention, respectively.

  The second circuit part 220 (see the broken line part) is provided in parallel to the first circuit part 210 and includes two resistance elements 221 and 222. The resistance elements 221 and 222 are connected in series to the ground (ground terminal) 120. That is, one terminal 221a of the resistance element 221 is connected to the node N17, and the other terminal 221b of the resistance element 221 is connected to the one terminal 222a of the resistance element 222 via the node N16. The other terminal 222b of the resistance element 222 is connected to the ground (ground terminal) 120 via the node N15. In the second embodiment, the resistance values of the resistance element 221 and the resistance element 222 are R5 (about 20 kΩ) and R6 (about 2.5 kΩ), respectively. The node N15 on the ground 120 side of the resistance element 222 is connected to the switches 230a, 230c, 230e, and 230g. The node N16 is connected to the switches 230b, 230d, 230f, and 230h. Node N17 is connected to switches 230i, 230j, 230k, and 230l. The resistance elements 221 and 222 are examples of the “second resistance element” in the present invention.

  In the second embodiment, the number (three) of resistance elements (resistance elements 212, 213, and 214) provided on the ground 120 side with respect to the output terminal 40 of the first circuit section 210, and the second circuit section 220. The number of the resistance elements 221 and 222 (two) is set to be 1.

  Each of the twelve switches 230a to 230l has a pair of one of all the nodes N11 to N14 of the first circuit unit 210 and one of all the nodes N15 to N17 of the second circuit unit 220, respectively. Connected individually. Each of the switches 230a to 230l individually connects one of the nodes N11 to N14 of the first circuit unit 210 and one of the nodes N15 to N17 of the second circuit unit 220, respectively. Different electric paths from the power source 110 to the ground 120 can be individually formed. That is, when any one of the twelve switches 230a to 230l is connected (ON state), the connection position of the switches 230a to 230l (any one of the nodes N11 to N14) in the first circuit unit 210. In the second circuit section 220, the resistance elements (11, 212, 213, and 214) arranged on the power supply 110 side and the connection positions of the switches 230a to 230l (any one of the nodes N15 to N17) are closer to the ground 120 side. An electrical path is formed through the arranged resistance elements (221, 222). In the second embodiment, the input circuit 200 has the resistance elements 212, 213, 214, 221 and 222 (on the respective electric paths to be connected, even when any of the switches 230a to 230l is depressed. The combined resistance values Rx by the combination of the resistance elements on the ground 120 side with respect to the output terminal 40 are different from each other.

  In addition, the other structure of 2nd Embodiment is the same as that of the said 1st Embodiment.

  Next, the operation of the input circuit 200 according to the second embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 4, in a state where none of the switches 230a to 230l is pressed down (off state), the first circuit unit 210 and the second circuit unit 220 are not electrically connected. The voltage to be applied is V0 (about 3.3 [V]) which is the same as the voltage of the power supply 110.

  As shown in FIG. 3, by turning on the switch 230a, the node N11 of the first circuit unit 210 and the node N15 of the second circuit unit 220 are connected, and the output terminal 40 is connected to the ground 120. Thereby, as shown in FIG. 3, the voltage (voltage output from the output terminal 40) detected by the input port of the microcomputer 50 becomes about 0 [V].

  Also, by turning on the switch 230b, the node N11 of the first circuit unit 210 and the node N16 of the second circuit unit 220 are connected, and an electric path passing through the resistance elements 11 and 222 is formed in the input circuit 200. The At this time, the resistance value of the electrical path (resistive element 222) on the ground 120 side with respect to the output terminal 40 is R6 = about 2.5 kΩ. Thereby, the voltage detected by the input port of the microcomputer 50 (voltage output from the output terminal 40) is about 0.66 [V].

  Also, by turning on the switch 230c, the node N12 of the first circuit unit 210 and the node N15 of the second circuit unit 220 are connected, and an electric path passing through the resistance elements 11 and 212 is formed in the input circuit 200. The At this time, the resistance value of the electrical path (resistive element 212) on the ground 120 side with respect to the output terminal 40 is R7 = about 5 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 1.1 [V].

  Further, by turning on the switch 230d, the node N12 of the first circuit unit 210 and the node N16 of the second circuit unit 220 are connected, and an electric path passing through the resistance elements 11, 212, and 222 is connected to the input circuit 200. It is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R6 + R7 = about 7.5 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 1.41 [V].

  Further, by turning on the switch 230e, the node N13 of the first circuit unit 210 and the node N15 of the second circuit unit 220 are connected, and an electric path passing through the resistance elements 11, 212, and 213 is connected to the input circuit 200. It is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R7 + R8 = about 10 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 1.65 [V].

  Further, by turning on the switch 230f, the node N13 of the first circuit unit 210 and the node N16 of the second circuit unit 220 are connected, and the electric current passing through the resistance elements 11, 212, 213, and 222 to the input circuit 200 is connected. A path is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R6 + R7 + R8 = about 12.5 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 1.83 [V].

  Also, by turning on the switch 230g, the node N14 of the first circuit unit 210 and the node N15 of the second circuit unit 220 are connected, and the electric power passing through the resistance elements 11, 212, 213, and 214 to the input circuit 200 A path is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R7 + R8 + R9 = about 15 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 1.98 [V].

  Further, by turning on the switch 230h, the node N14 of the first circuit unit 210 and the node N16 of the second circuit unit 220 are connected, and the resistance elements 11, 212, 213, 214, and 222 are connected to the input circuit 200. An electrical path through is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R6 + R7 + R9 = about 17.5 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 2.1 [V].

  Also, by turning on the switch 230i, the node N11 of the first circuit unit 210 and the node N17 of the second circuit unit 220 are connected, and an electric path passing through the resistance elements 11, 221 and 222 is connected to the input circuit 200. It is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R5 + R6 = about 22.5 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 2.28 [V].

  Further, by turning on the switch 230j, the node N12 of the first circuit unit 210 and the node N17 of the second circuit unit 220 are connected, and the electric current passing through the resistance elements 11, 212, 221 and 222 to the input circuit 200 is connected. A path is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R5 + R6 + R7 = about 27.5 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 2.42 [V].

  Further, by turning on the switch 230k, the node N13 of the first circuit unit 210 and the node N17 of the second circuit unit 220 are connected, and the resistance elements 11, 212, 213, 221 and 222 are connected to the input circuit 200. An electrical path through is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R5 + R6 + R7 + R8 = about 32.5 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 2.52 [V].

  Also, by turning on the switch 230l, the node N14 of the first circuit unit 210 and the node N17 of the second circuit unit 220 are connected, and all the resistive elements 11, 212, 213, 214, An electrical path through 221 and 222 is formed. At this time, the combined resistance value of the electric path on the ground 120 side with respect to the output terminal 40 is Rx = R5 + R6 + R7 + R8 + R9 = about 37.5 kΩ. Thereby, the voltage output from the output terminal 40 becomes about 2.61V].

  In this way, each of the twelve switches 230a to 230l is turned on by changing the combination of the resistance elements 11, 212, 212, 213, 221 and 222 arranged on the electric path. A voltage having a magnitude corresponding to the two switches 230 a to 230 l is output from the output terminal 40.

  In the second embodiment, as described above, the first circuit unit 210 including the four resistance elements 11, 212, 213, and 214 and the two resistance elements 221 provided in parallel to the first circuit unit 210 are provided. And the second circuit unit 220 including the second circuit unit 220, and the nodes N11 to N14 respectively connecting the resistance elements 11 and 212 to 214 of the first circuit unit 210 by the twelve switches 230a to 230l, and the second circuit unit. Twelve different electrical paths are individually formed by individually connecting a pair of nodes N15 to N17 respectively connecting 220 resistance elements 221 and 222. With this configuration, when any one of the twelve switches 230a to 230l is connected (ON state), the connection position (node N11) of the switches 230a to 230l in the first circuit unit 210. To any one of N14) and the second circuit unit 220 provided in parallel to the first circuit unit 210 and the connection position of the switches 230a to 230l (nodes N15 to N14). An electrical path that passes through the resistance element disposed on the ground 120 side with respect to any one of N17) is formed. As a result, in the input circuit 200 as a whole, the number of resistance elements (212 to 214, 221 and 222) for dividing the voltage of the power supply 110 by setting any one of the switches 230a to 230l to the connected state (ON state). And the combination of the resistance elements (212 to 214, 221 and 222) can be made different. Thereby, six resistance elements (212 to 214, 221 and 222) can be combined to output 12 patterns of voltages (voltage division) corresponding to the switches 230a to 230l.

  In the second embodiment, the number (three) of resistance elements (212 to 214) arranged on the ground 120 side with respect to the output terminal 40 of the first circuit unit 210 and the output terminal of the second circuit unit 220 40. The nodes N11 to N17 are individually connected to each other by configuring so that the difference from the number (two) of the resistance elements (221 and 222) arranged on the ground 120 side with respect to 40 is 1. Thus, the number of combinations (12 types) of resistance elements (212 to 214, 221 and 222) that can be arranged on the electric path formed can be increased. That is, for example, four resistance elements arranged on the ground 120 side with respect to the output terminal 40 are provided on the first circuit portion side, and only one is provided on the second circuit portion side. In this case, there are 5 × 2 = 10 combinations of resistance elements obtained by connection between the terminals. On the other hand, by providing three resistance elements (212 to 214) in the first circuit section 210 and providing two resistance elements (221 and 222) in the second circuit section 220, combinations of twelve resistance elements are possible. Can be obtained. Accordingly, different voltages can be output from the output terminal 40 depending on the combination of the resistance elements (212 to 214, 221 and 222) arranged on the electric path. That is, the number (12) of switches 230a to 230l that can be determined by outputting different voltages from the output terminal 40 can be increased.

  The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first and second embodiments, the input circuit 100 of the present invention is applied to an input circuit that accepts input of various operation keys provided in an operation unit of a DVD recorder or a digital television receiver. The present invention is not limited to this. The input circuit of the present invention can be widely applied to an input circuit of an operation unit of a device other than a DVD recorder or a digital television receiver.

  Moreover, in the said 1st and 2nd embodiment, although switch 30a-30i (230a-230l) showed the example comprised with the push switch which will be in a non-connection state in a normal state, this invention is not limited to this. . For example, a toggle switch other than the push-down switch may be used as the switch.

  In the first and second embodiments, an example is shown in which the number and combination of resistance elements on the electrical path on the ground 120 side with respect to the output terminal 40 are changed using a plurality of switches. However, the present invention is not limited to this. In the present invention, the number and combination of resistance elements on the electric path on the power source side with respect to the output terminal may be changed using a plurality of switches.

  In the first and second embodiments, the example in which one second circuit unit 20 is provided in parallel with respect to the first circuit unit 10 connected to the power supply is shown. Not limited. In the present invention, a plurality of second circuit units may be provided in parallel to the first circuit unit. In this case, each node of the first circuit unit (one of the one terminal and the other terminal of each resistor element) and each node of the plurality of second circuit units (one of the one terminal and the other terminal of each resistor element) are switched. Each can be connected individually using

  In the first and second embodiments, the first circuit unit and the second circuit unit are configured as one electrical path in which resistance elements are connected in series, and the first circuit unit and the second circuit unit. Are illustrated as being connected by a plurality of switches (see FIGS. 1 and 3), but the present invention is not limited to this. For example, as in the modification of the first embodiment shown in FIG. 5 and the modification of the second embodiment shown in FIG. 6, the first circuit portion and the second circuit portion are respectively divided into three pieces A, B, and C. A parallel path may be included, and the parallel paths of A, B, and C may be connected by switches. In the input circuit 100a of the modification of the first embodiment shown in FIG. 5, the same reference numerals as those of the input circuit 100 of the first embodiment are used for the resistance elements and the nine switches. The combination of resistance elements on the electrical path when each switch is pressed down and the magnitude of the voltage output from the output terminal are configured to be the same as in the first embodiment. In the input circuit 200a of the modification of the second embodiment shown in FIG. 6, the same reference numerals as those of the input circuit 200 of the second embodiment are used for the resistance elements and the twelve switches. The combination of resistance elements on the electrical path when each switch is pressed down and the magnitude of the voltage output from the output terminal are configured to be the same as in the second embodiment.

  In the first embodiment, the input circuit 100 is provided with five resistance elements. In the second embodiment, the input circuit 200 is provided with six resistance elements. The present invention is not limited to this. The number of resistance elements used in the input circuit may be 4 or less, or 7 or more. The number of resistance elements may be determined according to the number of switches.

  In the first embodiment, all the nodes N1 to N3 connected to one terminal and the other terminal of each of the resistance elements 12 and 13 of the first circuit unit 10, and the resistance element 21 of the second circuit unit 20 and Although an example is shown in which all nodes N4 to N6 connected to one terminal and the other terminal of 22 are individually connected one by one using the switches 30a to 30i, the present invention is not limited to this. . In the present invention, it is not necessary to connect all the terminals (all nodes) of the resistance elements of the first circuit section and all the terminals (all nodes) of the resistance elements of the second circuit section. The input circuit may be configured to individually connect only a part of the terminals (nodes) of the first circuit unit and the second circuit unit one by one using a switch.

  In the first embodiment, the difference between the number of resistance elements on the ground 120 side of the output terminal 40 of the first circuit unit 10 and the number of resistance elements of the second circuit unit 20 is configured to be zero. For example, in the second embodiment, the difference between the number of resistance elements on the ground 120 side of the output terminal 40 of the first circuit unit 210 and the number of resistance elements of the second circuit unit 220 is 1. Although the example which comprised was shown, this invention is not limited to this. You may comprise so that the difference of the number of the resistive elements of the ground side rather than the output terminal of a 1st circuit part and the number of the resistive elements of a 2nd circuit part may be two or more. However, for example, in the first embodiment, only one resistance element (two terminals) closer to the ground 120 than the output terminal 40 of the first circuit section 10 is provided, and three resistance elements of the second circuit section 20 are provided. (4 terminals) are provided. In this case, since there are 2 terminals × 4 terminals = 8 combinations that can be connected by switches, the number of switches with respect to the number of resistance elements is reduced.

10 1st circuit part 11 Resistance element (1st resistance element)
12, 13, 21, 22, 212, 213, 214, 221, 222 Resistance element (second resistance element)
20 2nd circuit part 30a-30i, 230a-230l switch (push-down switch)
40 Output terminal 50 Microcomputer (determination unit)
100, 100a, 200, 200a Input circuit 110 Power supply 120 Ground (ground terminal)

Claims (7)

A first circuit unit connected to a power source and including at least one resistive element;
A second circuit unit including at least one resistance element provided in parallel to the first circuit unit and connected to a ground terminal;
By connecting one of the one terminal and the other terminal of the resistance element of the first circuit portion and one of the one terminal and the other terminal of the resistance element of the second circuit portion, each other from the power source to the ground terminal is connected. A plurality of different electrical paths can be individually formed, and a plurality of switches each configured to be disconnected in a normal state;
It is arranged on a path from the power source to the ground terminal, and when the predetermined electric path is formed by connecting one switch of the plurality of switches, the predetermined electric path corresponds to the predetermined electric path An input circuit comprising: a resistance element of a first circuit unit; and an output terminal that outputs a voltage divided by the resistance element of the second circuit unit. Each of the plurality of switches includes a set of fixed contacts and movable contacts, and is an individual switch configured to be connected by connecting each set of movable contacts to a corresponding fixed contact.
When the predetermined electrical path is formed by connecting the movable contact of one of the plurality of individual switches to the corresponding fixed contact, the first corresponding to the predetermined electrical path. The voltage corresponding to the one individual switch is output from the output terminal by dividing the voltage of the power supply by the resistance element of each of the one circuit unit and the second circuit unit. The input circuit according to claim 1.   The input circuit according to claim 2, wherein the individual switch includes a push-down switch. The resistance element includes a first resistance element provided on the power supply side with respect to the output terminal, and a second resistance element provided on the ground terminal side with respect to the output terminal,
Each of the plurality of switches is connected to each of the switches to be connected by changing the combination of the second resistance elements arranged on the electric path formed individually by connecting each of the plurality of switches. The input circuit according to claim 1, wherein combined resistance values of the second resistance elements arranged on the respective electric paths are different from each other. The resistance element includes a first resistance element provided on the power supply side with respect to the output terminal, and a second resistance element provided on the ground terminal side with respect to the output terminal,
The one terminal and the other terminal of each of the second resistance elements of all the first circuit units are connected to the one terminal and the other terminal of all the second resistance elements of the second circuit unit. The input circuit according to any one of claims 1 to 4, wherein each of the input circuits is configured to be individually connectable. Each of the first circuit unit and the second circuit unit includes a plurality of second resistance elements,
6. The input circuit according to claim 4, wherein a difference between the number of the second resistance elements of the first circuit unit and the number of the second resistance elements of the second circuit unit is 0 or 1. 7.   And a determination unit that is connected to the output terminal and that determines which of the plurality of switches is connected based on a magnitude of a voltage output from the output terminal. Item 7. The input circuit according to any one of Items 1 to 6.

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