JPH1131955A - Input circuit and decision equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an input circuit which enables a CPU to determine, without changing an element, that a switch is turned on even when a signal inputted when a precedent switch is turned on is different. SOLUTION: When a power terminal 7 of a switch 6 is connected to a high- potential side power source (12v), a node N1 is at 6v with a switch 4 off and at about 12v with the switch 4 off. Further, when the power terminal 7 is grounded, the node N1 is at 6v with the switch 4 off and at almost 0v with the switch 4 on. An operational amplifier 3 compares the potential (3v) at the node N3 with the potential at the node N1 and outputs a signal showing the on or off state of the switch 4 when the power terminal 7 is grounded to the CPU 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an input circuit, and more particularly to an input circuit suitable as an input interface connected to an input port of a CPU provided in a vehicle.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional input circuit 50. The vehicle includes, for example, a key unlock warning switch (hereinafter referred to as a warning switch) 5 that is turned on / off depending on whether or not a key is inserted into a key cylinder.
1 is provided. The warning switch 51 is connected to a central processing unit (hereinafter referred to as a CPU) 52 such as a radio key receiver via an input circuit 50.
Connected to.

The warning switch 51
Depending on the type of vehicle, for example, the power supply terminal 53 is connected to a high-potential power supply of a battery, and is connected to ground. That is, when the warning switch 51 is turned on, the signal input to the input circuit 50 becomes + B level (battery power) depending on the type of vehicle, and GN
Some are at D level (ground).

Therefore, when the power supply terminal 53 is connected to the ground, as shown in FIG. 3, for example, an input circuit 50 using a 0Ω resistor R connected from the time of manufacture is used.
And

In this case, when the warning switch 51 is turned off, a current from the battery power supply 55 is supplied to the base of the transistor 54 in the input circuit 50, so that the transistor 54 is turned on and the transistor 5 is turned on.
An H level signal as an off signal is output to the CPU 52 through the CPU 4. When the warning switch 51 is turned on, the current from the battery power supply 55 flows to the ground via the diode 56, the 0Ω resistor R, the power supply terminal 53, and the like, so that the transistor 54 is turned off, and an ON signal is sent to the CPU 52. Is output as the L level signal.

On the other hand, when the power supply terminal 53 is connected to the power supply on the high potential side of the battery, the 0Ω resistor R is removed and the circuit element 5 shown in a broken line in FIG.
7 is connected to the input circuit 50.

In this case, when the warning switch 51 is turned off, the transistor 58 in the circuit element 57 is turned off.
A current is supplied from a battery power supply 55, the transistor 54 is turned on, and an H level signal is output to the CPU 52 via the transistor 54 as an off signal. When the warning switch 51 is turned on, the transistor 58 in the circuit element 57 is turned on.
6 and the ground 58 via the transistor 58 and the like. Therefore, the transistor 54 is turned off, and an L level signal is output to the CPU 52 as an ON signal.

As described above, in the conventional input circuit 50, there are two types of signals that are input when the preceding-stage circuit is turned on, that is, the signal at the + B level and the signal at the GND level. Is changed, the ON signal output to the CPU 52 is set to a constant level so that the CPU 52 can determine the ON state.

[0009]

However, in the conventional input circuit 50, it is necessary to change the 0Ω resistor R and the circuit element 57 according to the type of vehicle and the like, so that the change work is complicated. There's a problem.

In addition, since it is necessary to prepare the 0Ω resistor R and the circuit element 57 in advance, the number of parts increases, and various managements and the like for the elements R and 57 increase costs. There's a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a semiconductor device without changing elements even when a signal inputted when a preceding switch is turned on is different. An object of the present invention is to provide an input circuit capable of causing a CPU to determine that the switch is turned on.

[0012]

The invention according to claim 1 is provided between a switch and a judging device, and outputs a signal to that effect to the judging device based on the ON / OFF state of the switch. In the input circuit, when one end of the switch is connected to a high potential side power supply, the switch outputs a first detection voltage when the switch is off, and outputs a second detection voltage when the switch is on. Also, when one end of the switch is connected to a low-potential-side power supply, a detection circuit section that outputs a first detection voltage when the switch is off and outputs a third detection voltage when the switch is on. And the first to third detection voltages are input from the detection circuit unit, and based on the input first and second detection voltages, the switch when one end is connected to the high-potential-side power supply On or off signal A first output to the determination apparatus 1 of the decision and the output circuit section, the first to third from the detection circuit unit
, And based on the input first and third detection voltages, a signal indicating that the switch is on or off when one end is connected to the low-potential-side power supply is determined by the determination device. And a second determination output circuit section that outputs the result to the second determination output circuit section.

According to a second aspect of the present invention, in the input circuit of the first aspect, the detection circuit section that outputs the first to third detection voltages to the first and second determination output circuit sections is provided. A voltage dividing circuit comprising a plurality of voltage dividing resistors connected between a high potential side power supply and a low potential side power supply, wherein the other end of the switch is connected between the voltage dividing resistors. The gist is that.

According to a third aspect of the present invention, in the input circuit according to the second aspect, the first determination output circuit generates a first comparison voltage having a value higher than the first detection voltage. A first comparison voltage generation unit that compares the first and second detection voltages input from the detection circuit unit with the first comparison voltage, and outputs a first comparison result signal to the determination device; A second comparison voltage generation unit configured to generate a second comparison voltage having a value lower than the first detection voltage; and a second comparison voltage generation unit configured to generate a second comparison voltage having a value lower than the first detection voltage. And a second comparison device for comparing the first and third detection voltages input from the second device with the second comparison voltage and outputting a second comparison result signal to the determination device. .

According to a fourth aspect of the present invention, there are provided first and second input ports, and the first input port is provided in the first aspect.
2. A signal indicating an ON state or an OFF state is input from the first determination output circuit unit according to claim 1, and the second input port is turned on or off from the second determination output circuit unit according to claim 1. A signal indicating the state is input, and the input port to which the signal indicating the ON state is input for the first time among the first and second input ports is stored, and thereafter, the input port is input to the stored input port. The gist of the invention is a judging device for judging the ON / OFF state of the switch based only on a signal indicating an ON state or an OFF state.

According to the first aspect of the present invention, when one end of the switch is connected to the high-potential-side power supply, the detection circuit outputs the first detection voltage when the switch is in the off state, The second detection voltage is output in the ON state of. When one end of the switch is connected to the low potential side power supply, a first detection voltage is output when the switch is off, and a third detection voltage is output when the switch is on. One end of the first determination output circuit is connected to a high-potential-side power supply based on first and second detection voltages of the first to third detection voltages input from the detection circuit. A signal indicating that the switch is in the ON state or the OFF state is output to the determination device. One end is connected to a low-potential-side power supply based on first and third detection voltages of the first to third detection voltages input from the detection circuit unit from the second determination output circuit unit. A signal indicating that the switch is in the ON state or the OFF state is output to the determination device. Therefore, even when the switch is connected to either the high-potential-side power supply or the low-potential-side power supply, the determination device can determine that the switch has been turned on or off.

According to the second aspect of the present invention, the detection circuit section is a voltage dividing circuit in which a plurality of voltage dividing resistors are connected between a high potential side power supply and a low potential side power supply, The other end of the switch is connected between the voltage dividing resistors. Therefore,
By simply setting the ratio of the voltage dividing resistors, a desired first detection voltage can be easily generated between the voltage dividing resistors. or,
When the switch is turned on when one end of the switch is connected to the high-potential-side power supply, a second detection voltage higher than the first detection voltage is generated between the voltage dividing resistors. Further, when the switch is turned on when one end of the switch is connected to the low potential side power supply, a third detection voltage lower than the first detection voltage is generated between the voltage dividing resistors.

According to the third aspect of the present invention, the first comparison voltage generator generates a first comparison voltage having a higher value than the first detection voltage. The first comparison device compares the first and second detection voltages input from the detection circuit with the first comparison voltage, and outputs a first comparison result signal to the determination device. Therefore, the switch is turned on when one end of the switch is connected to the high potential side power supply,
When the second detection voltage having a value higher than the first comparison voltage is input, the first comparison result signal is inverted, so that the determination device can determine that the switch has been turned on.

In the second comparison voltage generator, a second comparison voltage having a value lower than the first detection voltage is generated. In the second comparison device, the first and third signals input from the detection circuit
Is compared with the second comparison voltage, and a second comparison result signal is output to the determination device. Therefore, when the switch is turned on when one end of the switch is connected to the low-potential-side power supply and the third detection voltage having a value lower than the second comparison voltage is input, the second comparison result signal is inverted. Therefore, the determination device can determine that the switch has been turned on.

According to the invention described in claim 4, the judging device is provided with the first and second input ports. The first input port is supplied with a signal indicating an ON state or an OFF state from the first determination output circuit unit, and the second input port is supplied with an ON state or OFF signal from the second determination output circuit unit. A signal indicating the state is input. Then, of the first and second input ports, the input port to which the signal indicating the ON state is input for the first time is stored, and thereafter, the ON state or the OFF state input to the stored input port is stored. The ON / OFF state of the switch is determined based only on the signal.
Therefore, the process of determining whether the switch is on or off can be shortened.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the input circuit 1 includes a battery operational amplifier 2 as a first comparative device, a GND operational amplifier 3 as a second comparative device, and first to sixth resistors R1 to R6. I have.

In the present embodiment, the input circuit 1 determines the on / off state of the warning switch 4 provided in the vehicle by, for example, the CP of a radio key receiver as a determination device.
This is a circuit for outputting to U5. The warning switch 4 is a switch which is turned on / off depending on whether or not a key is inserted into a key cylinder.

In the input circuit 1, one end of the second resistor R2 is connected to the battery power supply 6 (12v), and the other end is connected to the ground GND via the third resistor R3. 4th
The resistor R4 has one end connected to the battery power source 6 and the other end connected to the ground GN via a fifth resistor R5 and a sixth resistor R6.
D.

The warning switch 4 is connected to the connection point between the second resistor R2 and the third resistor R3, that is, the node N1, via the first resistor R1. The node N1 is connected to an inverting input terminal of the battery operational amplifier 2 and to a non-inverting input terminal of the GND operational amplifier 3.

The connection point between the fourth resistor R4 and the fifth resistor R5, that is, the node N2, is connected to the non-inverting input terminal of the operational amplifier 2 for battery. The connection point between the fifth resistor R5 and the sixth resistor R6, that is, the node N3 is connected to the GN
It is connected to the inverting input terminal of the D operational amplifier 3.
In this embodiment, the second and third resistors R2, R
Reference numeral 3 constitutes a detection circuit section and a voltage dividing circuit. Also, the fourth
The sixth to sixth resistors R4 to R6 constitute first and second comparison voltage generators.

An output terminal of the battery operational amplifier 2 is connected to an input port P1 of the CPU 5,
The output terminal of the ND operational amplifier 3 is connected to the input port P2 of the CPU 5. In the present embodiment,
Battery operational amplifier 2 and fourth to sixth resistors R4 to R6
Constitute a first decision output circuit section, and the GND operational amplifier 3 and the fourth to sixth resistors R4 to R6 constitute a second decision output circuit section.

In this embodiment, the second and third resistors R
2 and R3 are resistance elements having the same resistance value, and the fourth and sixth resistances R4 and R6 are resistance elements having the same resistance value. Fifth resistor R
Reference numeral 5 denotes a resistance element having a resistance twice the resistance of the fourth resistance R4, and the first resistance R1 is a resistance element having a resistance sufficiently smaller than the other resistances R2 to R6.

The input circuit 1 in which the values of the second to sixth resistors R2 to R6 are set as described above is connected to the warning switch 4
Is turned off, the potential of the node N1 as the first detection voltage becomes 6V, and the node N2 as the first comparison voltage
Becomes 9 V, and the potential of the node N as the second comparison voltage
The potential of 3 becomes 3v. At this time, an H level signal as an off signal is output from the battery operational amplifier 2 to the input port P1 of the CPU 5, and an H level signal as an off signal is output from the GND operational amplifier 3 to the input port P2 of the CPU 5.
A level signal is output.

When the power supply terminal 7 is connected to the high-potential power supply (12v) of the battery, when the warning switch 4 is turned on, the potential of the node N1 as the second detection voltage becomes approximately 12v. . Then, the inverting input terminal of the battery operational amplifier 2 has a higher potential than the non-inverting input terminal, and the battery operational amplifier 2 outputs an L level signal as an ON signal to the input port P1 of the CPU 5.

When the power supply terminal 7 is connected to the ground, when the warning switch 4 is turned on, the potential of the node N1 as the third detection voltage becomes almost 0V. Then, in the GND operational amplifier 3, the inverting input terminal has a higher potential than the non-inverting input terminal,
From the GND operational amplifier 3, the input port P of the CPU 5
2 outputs an L level signal as an ON signal.

That is, the input circuit 1 outputs an L level signal as an ON signal to the input port P1 when the signal input when the warning switch 4 is turned on is 12V, and when the signal is at the GND level. , Input port P
2 outputs an L level signal as an ON signal.

The CPU 5 is also supplied with an on / off signal I of an ignition switch, an on / off signal K of a courtesy switch for door open / close detection, and the like. Next, the C
The main part of the determination process of the PU 5 will be described with reference to the flowchart shown in FIG. Here, this determination processing includes, for example,
This is a process for the CPU 5 to determine whether the key is inserted into the key cylinder, whether the door is closed, and the like. The result of the determination is that a signal for putting the engine into an idling state is transmitted from the radio key. It is used when it comes.

Note that the flowchart of this determination processing is a closed loop, and the determination processing of the CPU 5
U5 is set in a predetermined connector, and starts from an initial state when a predetermined power is turned on.

In step S1, the CPU 5 determines whether the signal I from the ignition switch is an ON signal. When it is determined that the signal I is an ON signal, an ignition flag (hereinafter, referred to as an ignition flag) is determined in step S2.
IG flag) is set to “1”, and step S
Move to 3. If it is determined that the signal I is an off signal, the IG flag is set to "0" in step S4, and the process proceeds to step S8.

In step S3, the CPU 5 sets the IG flag to "1" for the first time from the initial state when the power is turned on.
Is set. When it is determined that "1" is set to the IG flag for the first time, it is determined in step S5 whether the signal input to the input port P1 is an ON signal, that is, whether the signal is at the L level. Also I
If it is determined that "1" has been set in the G flag, the process proceeds to step S8.

When the CPU 5 determines in step S5 that the signal of the input port P1 is an ON signal (L level), it sets "1" in a battery flag (hereinafter, referred to as a B flag) in step S6. Move to S8. Also, the signal of the input port P1 is an off signal (H level).
When it is determined that "1" is set in the GND flag in step S7, the process proceeds to step S8.

That is, in the processing of steps S5 to S7, when the ignition is turned on for the first time from the initial state, and when the ignition is turned on, the key is of course inserted, so that the input port P1, P2 , Which is inverted and becomes an ON signal (L level), and stores the input port thereof.

The CPU 5 determines in step S8 that B
It is determined whether the use flag is “1”. If the B flag is determined to be "1", it is determined in step S9 whether the signal input to the input port P1 is an ON signal (L level).

When it is determined that the signal of the input port P1 is an ON signal (L level), a key unlock warning flag (hereinafter, referred to as a KW flag) is set to "1" in step S10, and the subsequent processing is performed. Move on to If it is determined in step S9 that the signal at the input port P1 is an off signal (H level), the process proceeds to step S11.
The flag for W is set to "0", and the process proceeds to the subsequent stage.

That is, in the process of step S8, it is determined whether the input port stored in steps S5 to S7 is the input port P1. If the stored input port is the input port P1, steps S9 to S11
In the above processing, it is determined whether the key is inserted into the key cylinder based only on the signal input to the input port P1, and the result is stored.

The CPU 5 determines in step S8 that B
When the use flag is determined to be “0”, G is determined in step S12.
It is determined whether the ND flag is “1”. And G
If the ND flag is determined to be "1", it is determined in step S13 whether the signal input to the input port P2 is an ON signal (L level).

If it is determined that the signal at the input port P2 is an ON signal (L level), at step S14 the K
The flag for W is set to "1", and the process proceeds to the subsequent stage.
If it is determined in step S13 that the signal of the input port P2 is an off signal, the KW flag is set to "0" in step S15, and the process proceeds to a subsequent stage.

That is, in the process of step S12,
It is determined whether the input port stored in steps S5 to S7 is the input port P2. When the stored input port is the input port P2, steps S13 to S13 are executed.
In the process of 15, it is determined whether the key is inserted into the key cylinder based only on the signal input to the input port P2, and the result is stored.

If the CPU 5 determines in step S12 that the GND flag is "0", the process proceeds to the subsequent stage. That is, in the processing of steps S8 and S12,
If it is determined that neither of the input ports P1 and P2 has been stored yet, the process proceeds to the subsequent stage without determining whether the key is inserted into the key cylinder.

In the subsequent processing, for example, it is determined whether or not the signal K from the courtesy switch is an ON signal. Next, the characteristic operation and effect of the above embodiment will be described below.

(1) In the present embodiment, when the warning switch 4 is turned off, the node N1 becomes 6v. When the power supply terminal 7 is connected to the high-potential power supply (12v) of the battery, when the warning switch 4 is turned on, the node N1 becomes almost 12v, and the signal output from the operational amplifier 2 for battery is inverted. Power supply terminal 7
Is connected to the ground, when the warning switch 4 is turned on, the node N1 becomes almost 0 V,
The signal output from the GND operational amplifier 3 is inverted.
Therefore, regardless of whether the signal input from the switch 4 is 12 V or the ground, the input circuit 1 allows the CPU 5 to turn on the warning switch 4 without changing the element as in the related art. Can be determined. As a result, there is no need for a conventional element changing operation. In addition, there is no need to prepare elements, and the number of components is reduced. Therefore, costs such as management costs can be reduced.

(2) In this embodiment, the CPU
In the judgment process, when the ignition is turned on from the initial state of power-on, the input ports P1, P
Which of the two has become the ON signal (L level) is determined and stored. Then, in the subsequent determination as to whether or not the key is inserted into the key cylinder, the determination is made based only on the signal input to the stored input port. Therefore, the processing for determining the ON / OFF state of the warning switch 4 can be shortened.

(3) In this embodiment, the battery power source 6
(12v) and the ground GND, the second and third resistors R2 and R3 are connected in series, and the second and third resistors R2 and R3 are connected in series.
Since the warning switch 4 is connected between R2 and R3, the potential of the node N1 when the warning switch 4 is turned off is set to a desired potential only by setting the resistance values of the second and third resistors R2 and R3. be able to. When the switch is turned on when the power supply terminal 7 is connected to the high-potential power supply (12v) of the battery, the potential of the node N1 becomes a desired high potential. Further, when the power supply terminal 7 is connected to the ground, the warning switch 4
Is turned on, the potential of the node N1 becomes a desired low potential.

(4) In this embodiment, the battery power source 6
(12v) and the ground GND, the fourth to sixth resistors R
Since the fourth to sixth resistors R4 to R6 are connected in series,
Only by setting the resistance value of R6, the potential of the node N2 and the potential of the node N3 can be set to desired potentials.

(5) In this embodiment, an operational amplifier is used to compare the potential of the node N1, the potential of the node N2, and the potential of the node N3. Since the operational amplifier has an extremely high input resistance, each node N
It does not affect the potentials of 1 to N3. Further, since almost no current flows in the operational amplifier, the voltage of the battery power supply does not drop.

The above embodiment may be modified and implemented as follows. In the above embodiment, the fourth to sixth resistors R4 to R6 connected between the battery power source 6 and the ground GND are connected to the potentials of the nodes N2 and N3 for comparison with the potential of the node N1.
However, any voltage generation circuit may be used as long as a desired potential is obtained.

In the above embodiment, the H level is output when the warning switch 4 is off, and the L level is output when the warning switch 4 is on. However, the operational amplifier 2 for battery and the operational amplifier for GND are output. 3 connected to respective inverting input terminals and non-inverting input terminals.
3 may be connected in reverse to output an L level when it is off and an H level when it is on.

In the above embodiment, the input circuit 1 is an input interface for transmitting the on / off state of the warning switch 4 to the CPU 5 of the radio key receiver. However, the present invention is not limited to this. If the input interface is different depending on various conditions, the input interface may be used for any device such as an electric product.

The first to sixth resistors R1 to R1 of the above embodiment
The resistance value of R6 is such that when the power supply terminal 7 is connected to the high-potential power supply of the battery and the warning switch 4 is turned on, the output of the battery operational amplifier 2 can be inverted, and the power supply terminal 7 is connected to the ground. If the output of the GND operational amplifier 3 can be inverted when the warning switch 4 is turned on, any resistance value may be used.

The technical ideas other than the claims that can be grasped from the above embodiment will be described below together with their effects. (A) The input circuit according to claim 3, wherein the first and second comparison devices (2, 3) are operational amplifiers (2, 3).

In this way, the potential of each of the nodes N1 to N3 due to the voltage dividing resistor does not affect. Also, there is no voltage drop in the battery power supply.

[0057]

As described above in detail, according to the first to third aspects of the present invention, even if the signal input when the preceding switch is turned on is different, the element is not changed without changing the element.
An input circuit which can cause the CPU to determine that the switch has been turned on can be provided.

According to the invention set forth in claim 4, according to claim 1
In the determination device to which the signal indicating the ON state or the OFF state is input from the input circuit described in (1), the process of determining the ON / OFF state of the switch can be shortened.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an input circuit in this embodiment.

FIG. 2 is a flowchart for explaining a determination process of a CPU of the radio key receiver according to the embodiment;

FIG. 3 is a circuit diagram showing an input circuit according to a conventional technique.

[Explanation of symbols]

2 ... Battery operational amplifier, 3 ... GND operational amplifier,
4 Warning switch 5 Radio key receiver C
PU, 6: battery power, GND: ground, R2 to R
6 ... second to sixth resistors, P1, P2 ... input ports.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masashi Sakurai 1 Noda, Toyota, Oguchi-machi, Oguchi-cho, Niwa-gun, Aichi Prefecture Inside Tokai Rika Electric Works

Claims (4)

[Claims] An input which is provided between a switch (4) and a judging device (5) and outputs a signal to that effect to the judging device (5) based on an on / off state of the switch (4). In the circuit, when one end of the switch (4) is connected to a high-potential-side power supply, a first detection voltage is output when the switch (4) is off, and the first detection voltage is output when the switch (4) is on. 2 and outputs a first detection voltage when the switch (4) is off when one end of the switch (4) is connected to a low-potential-side power supply. 4)
A detection circuit section (R
2, R3), the first to third detection voltages are input from the detection circuit section, and one end is connected to a high-potential-side power supply based on the input first and second detection voltages. A first determination output circuit section (2, R4 to R4) for outputting a signal to the effect that the switch (4) is in an ON state or an OFF state at the time to the determination device (5).
R6), the first to third detection voltages are input from the detection circuit unit, and based on the input first and third detection voltages, when one end is connected to the low potential side power supply. A second determination output circuit section (3, R4 to R4) for outputting a signal indicating that the switch (4) is on or off to the determination device (5);
R6). 2. The input circuit according to claim 1, wherein said detection circuit sections (R2, R3) for outputting first to third detection voltages to said first and second determination output circuit sections have a high level. A voltage dividing circuit comprising a plurality of voltage dividing resistors (R2, R3) connected between a potential side power supply (6) and a low potential side power supply (GND), wherein the other end of the switch (4) is An input circuit connected between the voltage dividing resistors (R2, R3). 3. The input circuit according to claim 2, wherein the first determination output circuit section (2, R4 to R6) generates a first comparison voltage having a value higher than the first detection voltage. A first comparison voltage generation unit (R4 to R6), and first and second detection voltages input from the detection circuit units (R2, R3) are compared with the first comparison voltage. A first comparison device (2) that outputs a comparison result signal to the determination device, wherein the second determination output circuit unit (3, R4 to R6) has a value lower than the first detection voltage. (2) a second comparison voltage generator (R4 to R6) for generating a comparison voltage; first and third detection voltages input from the detection circuit units (R2, R3); and a second comparison voltage. And a second comparison device (3) that outputs a second comparison result signal to the determination device. An input circuit characterized by: 4. The first and second input ports (P1, P2)
2), wherein the first input port (P1) receives a signal indicating an ON state or an OFF state from the first determination output circuit unit according to claim 1, and the second input port (P1). P2) receives a signal indicating an ON state or an OFF state from the second determination output circuit unit according to claim 1; and among the first and second input ports (P1, P2),
The input port (P1, P2) to which the signal indicating the ON state is input for the first time is stored, and thereafter, only the signal indicating the ON state or the OFF state input to the stored input port (P1, P2) is stored. A determination device for determining the on / off state of the switch based on the determination.