JP2014033713A - Opening/closing detection circuit and electric device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opening/closing detection circuit, when it is impossible to accurately receive a detection signal from a detection part representing whether a lid body is in one of an open state or a closed state, capable of determining the state, and an electric device including the same.SOLUTION: Each of hall ICs 56a and 56b detects an open state or a closed state of a lid body and outputs a signal. When the lid body is in the open state, a potential of a signal is a high level, and when the lid body is in the closed state, the potential of the signal is a low level. When the transmission of a detection signal s1 is stopped, a pullup circuit 18a pulls up the potential of a transmission passage of the detection signal s1 to a high level. When the transmission of a detection signal s2 is stopped, a pull-down circuit 18b pulls down the potential of the transmission passage of the detection signal s2 to a low level. When the potentials of the detection signals s1 and s2 are mutually different, a main CPU 10a determines an occurrence of a failure in the detection of the open state and the closed state of the lid body.

Description

  The present invention relates to an open / close detection circuit and an electric device including the same.

  An open / close detection circuit is used to detect whether the lid or the door is in an open state or a closed state. In an electric device including an open / close detection circuit, the control is changed according to the detection result of the open / close detection circuit. An example of such an electric device is disclosed in Japanese Patent Laid-Open No. 8-154814 (Patent Document 1). The rice cooker disclosed in Patent Document 1 detects a pan that accommodates an object to be heated, a pan heating coil that induction-heats the pan, a lid that is attached to the top of the pan, and an open state and a closed state of the lid. And a heating unit provided on the lid, an inverter circuit that supplies a high-frequency output to the pan heating coil, and a control circuit that receives the signal from the detection unit and controls the heating unit and the inverter circuit.

  When storing an object to be heated while keeping the temperature in the rice cooker, steam generated from the object to be heated adheres to the lid as water droplets. For this reason, this water droplet is evaporated by energizing the heating part of the lid. However, when the lid is in the open state, water droplets do not adhere. Therefore, the detection unit outputs a signal to the control circuit when detecting that the lid is in the open state. Thereby, the energization to the heating part of the lid is stopped. As a result, unnecessary power consumption can be reduced.

JP-A-8-154814

  The detection unit needs to be provided around the opening or on the lid. If possible, it is desirable to mount a control circuit (for example, a CPU (Central Processing Unit)) that receives a detection signal from the detection unit on the same substrate as the detection unit. However, in general, the control circuit requires a larger substrate area than the detection unit. Therefore, there may be a case where a sufficient space for arranging the control circuit in addition to the detection unit cannot be secured around the opening or the lid.

  In this case, the control circuit is mounted on a separate substrate from the detection unit. Thereby, it is possible to provide the detection unit around the opening and the lid, and to provide the control circuit away from the detection unit. On the other hand, a connection part (for example, a connector and a harness) for electrically connecting the detection part and the control circuit is essential.

  When opening and closing the lid, vibration and impact often occur. Due to this vibration or impact, there is a possibility that a problem occurs in the connection state of the connection portion. Specifically, there is a possibility that the connection of the connector is loosened and a contact failure occurs in the connector terminal. As a result, the control circuit cannot accurately receive the detection signal from the detection unit. As a result, the control circuit cannot appropriately control the electric device depending on whether the lid is in the open state or the closed state.

  Therefore, the present invention has been made in order to solve the above-described problems, and an object of the present invention is to accurately detect a detection signal from a detection unit indicating whether the lid is in an open state or a closed state. It is an object to provide an open / close detection circuit capable of determining that and an electric device including the same.

  According to an aspect of the present invention, an open / close detection circuit used in an electric device including a main body and a lid attached to the main body so as to be openable / closable includes a first and a second detection section, a control circuit, , A connection unit, a pull-up circuit, and a pull-down circuit. Each of the first and second detection units detects a lid open state and a closed state and outputs a signal, and the lid is in a first state corresponding to one of the open state and the closed state. In some cases, the signal potential is at a high level, and when the lid is in the second state corresponding to the other of the open state and the closed state, the signal potential is at a low level. The control circuit receives the signal of the first detection unit as the first detection signal, receives the signal of the second detection unit as the second detection signal, and the lid is in the first and second states. Judge which one it is. The connection unit electrically connects each of the first and second detection units and the control circuit. The pull-up circuit is provided in the transmission path of the first detection signal between the connection unit and the control circuit, and when the transmission of the first detection signal is interrupted, the pull-up circuit sets the potential of the transmission path of the first detection signal. Pull up to high level. The pull-down circuit is provided in the transmission path of the second detection signal between the connection unit and the control circuit, and when the transmission of the second detection signal is interrupted, the potential of the transmission path of the second detection signal is lowered. Pull down to level. The control circuit determines that the lid is in the first state when the potentials of the first and second detection signals are both at a high level. The control circuit determines that the lid is in the second state when the potentials of the first and second detection signals are both at a low level. The control circuit determines that a problem has occurred in detecting the open state and the closed state of the lid when the potentials of the first and second detection signals are different from each other.

  According to the present invention, the control circuit can determine that it cannot accurately detect whether the lid is in the open state or the closed state.

  Preferably, the control circuit determines that a failure has occurred in the connection state of the connection portion when the potential of the first detection signal is high and the potential of the second detection signal is low. .

  According to the present invention, when the open / close detection circuit cannot accurately detect whether the lid is in the open state or the closed state, it is possible to identify the location where the malfunction of the open / close detection circuit occurs.

  Preferably, the control circuit has at least one of the first detection unit and the second detection unit when the potential of the first detection signal is low and the potential of the second detection signal is high. It is determined that a problem has occurred.

  According to the present invention, when the open / close detection circuit cannot accurately detect whether the lid is in the open state or the closed state, it is possible to identify the location where the malfunction of the open / close detection circuit occurs.

  Preferably, the control circuit has at least one of the first detection unit and the second detection unit when the potential of the first detection signal is high level and the potential of the second detection signal is low level. Is determined to have failed.

  According to the present invention, when the open / close detection circuit cannot accurately detect whether the lid is in the open state or the closed state, it is possible to identify the location where the malfunction of the open / close detection circuit occurs.

Preferably, the control circuit is configured such that when the potential of the first detection signal is at a low level and the potential of the second detection signal is at a high level, the potential of the first and second detection signals by the control circuit. According to the present invention, when the open / close detection circuit cannot accurately detect whether the lid is in the open state or the closed state, the failure occurrence point of the open / close detection circuit is determined. Can be identified.

  An electric device according to another aspect of the present invention includes a main body, a lid, and the open / close detection circuit.

  ADVANTAGE OF THE INVENTION According to this invention, the electric equipment which a control circuit can judge that an open / close detection circuit cannot detect correctly whether it is an open state or a closed state is realizable.

  Preferably, the electrical device further includes a notification unit that notifies the user of the occurrence location of the malfunction of the electrical device. When it is determined that a malfunction has occurred in the open / close detection circuit, the control circuit controls the notification unit so as to notify the user to that effect.

According to the present invention, the user can know the occurrence of a malfunction in the open / close detection circuit.
Preferably, the electric device further includes a heating chamber for accommodating the object to be heated and heating the object to be heated. The heating chamber is provided inside the main body so as to be opened and closed by the lid. The control circuit controls the heating chamber so as to stop heating when it is determined that a malfunction has occurred in the open / close detection circuit.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent more reliably that a to-be-heated material is heated when a cover body is an open state.

  Preferably, the electric device further includes a drive unit controlled by the control circuit and a driven body driven by the drive unit. The driven body is provided inside the main body so as to be opened and closed by the lid. The control circuit controls the drive unit to stop driving the driven body when it is determined that a failure has occurred in the open / close detection circuit.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent more reliably that a to-be-driven body drives when a cover body is an open state.

  According to the present invention, the open / close detection circuit can determine that it cannot accurately detect whether the lid is in the open state or the closed state.

It is a schematic perspective view in the closed state of the lid of the rice cooker concerning an embodiment. It is a schematic perspective view in the open state of the cover of a rice cooker. It is a schematic bottom view of the rotary body of a rice cooker. It is a schematic perspective view for demonstrating the stirring state of a 1st, 2nd stirring body. It is a schematic top view of a rice cooker. It is an enlarged view of the liquid crystal display part of a rice cooker. It is a schematic sectional drawing of a rice cooker. It is a block diagram showing the outline | summary of the structure of the control system of a rice cooker. It is a block diagram showing the detail of the main control system in the control system structure of FIG. It is a block diagram showing the detail of the sub control system in the control structure of FIG. FIG. 10 is a circuit diagram illustrating details of a circuit of the lid opening / closing detection unit of FIG. 9. It is a flowchart showing an example of the flow of judgment at the time of receiving a detection signal in the control circuit. 12 is a diagram illustrating combinations of potentials of detection signals s1 and s2 and causes that are considered to cause each of the combinations in the lid open / close detection circuit illustrated in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  In the following examples, a rice cooker that is a cooking device will be described as a specific example of the electric device according to the present invention. Of course, the electric device is not limited to a rice cooker, and may be another cooking device such as an oven or a microwave oven, or is not limited to a cooking device, and may be other household appliances such as a washing machine or a vacuum cleaner. It may also be a general electric device such as a CD player or a mobile phone without being limited to the home appliance. The electrical device according to the present invention may be any electrical device as long as it has an open state and a closed state, for example, by opening and closing a lid.

  Such an electric device is a form for accommodating an object such as a rice cooker, a washing machine, a dryer, a mixer, a refrigerator, a CD player, etc., and has a lid with respect to a main body having an accommodation space for accommodation. Refers to those that can be opened and closed. In the case of an apparatus that does not store an object inside, one housing that is opened and closed can be referred to as a “main body”, and the other housing can be referred to as a “lid”. For example, in the case where the electrical device is an openable / closable mobile phone, the casing on the side provided with numeric keys and the like is referred to as a “main body”, and the casing provided with the liquid crystal screen is referred to as a “lid”. be able to. For example, when the electric device is a fan, a wire mesh provided so as to surround the fan can be referred to as a “lid”. A state in which the fan cannot touch the fan by the wire mesh corresponds to the closed state, and a state in which all or part of the wire mesh is removed and the fan can be touched corresponds to the open state. The fan is an example of a driven body.

<Device configuration>
FIG. 1 is a schematic perspective view of rice cooker 100 according to the present embodiment as viewed obliquely from above.

  With reference to FIG. 1, rice cooker 100 includes rice cooker body 1 and lid 2 attached to rice cooker body 1 so as to be openable and closable. The rice cooker body 1 is located below the lid 2. An opening 1 a (see FIG. 2) is formed on the upper surface of the rice cooker body 1. The opening 1 a is opened and closed by the lid 2. The rice cooker body 1 is an example of a “main body”.

  An open button 3 for opening the lid 2 is arranged on the front surface of the rice cooker body 1. A power cord 47 is disposed on the rear surface of the rice cooker body 1. Most of the power cord 47 is wound around a cord reel (not shown) in the rice cooker body 1 so that it can be pulled out.

  A liquid crystal display unit 5 for displaying a cooking method, a cooking name, and the like and a plurality of operation switches 6 are arranged on the front part of the upper surface of the lid 2. Furthermore, the operation switch 6 is provided with an LED (Light Emitting Diode) indicator 61 for indicating an operation state. The operation switch 6 may be a switch that accepts a physical press, or may be a capacitive touch key. When the operation switch 6 is a capacitive touch key, the backlight of the touch key may be used instead of the LED indicator 61.

  A steam discharge port 2a for discharging the steam in the inner pot 7 (see FIG. 2) is provided at the rear part of the upper surface of the lid 2.

FIG. 2 is a schematic perspective view of the rice cooker 100 in the open state of the lid 2.
With reference to FIG. 2, the rice cooker main body 1 accommodates an inner pot 7 for accommodating rice or water as an example of an object to be heated.

  A locked portion 8 is provided at the front portion of the upper surface of the rice cooker body 1. A locking portion 23 is provided at the front portion of the lower surface of the lid 2. The locking portion 23 is releasably locked to the locked portion 8.

  In the rice cooker body 1, a lid lock portion 9 for locking the lid 2 is provided. When the lid lock portion 9 does not lock the lid body 2, when the open button 3 is pressed, the locked portion 8 moves backward. For this reason, the locking of the locking portion 23 with respect to the locked portion 8 is released. When the lid lock portion 9 locks the lid body 2, the locked portion 8 does not move rearward even if the open button 3 is pressed. For this reason, the locking of the locking portion 23 with respect to the locked portion 8 is not released.

  The lid body 2 includes an outer lid 21 located on the opposite side to the inner pot 7 side in the closed state of the lid body 2 and an inner lid 22 located on the inner pot 7 side in the closed state of the lid body 2.

  A stirring motor 24 is installed in the outer lid 21. A connecting shaft (not shown) is rotatably installed in the central portion of the outer lid 21 and receives the rotational driving force generated by the stirring motor 24 via a pulley (not shown) and a belt (not shown). Rotate.

  A rotating body 25 is rotatably disposed between the rice cooker body 1 and the lid body 2 and is detachably attached to the lid body 2. More specifically, one end of the rotating shaft 29 protrudes from the portion of the rotating body 25 on the lid 2 side (see FIG. 4). One end of the rotating shaft 29 is detachably connected to the connecting shaft of the outer lid 21 and rotates integrally with the connecting shaft. The rotating shaft 29 is rotatable with respect to the rotating body 25.

  The rotating body 25 is provided with first and second stirring bodies 26A and 26B (which are also referred to as stirring bodies 26 as representative). The first and second stirring bodies 26A and 26B are adjacent to the rotating body 25 in the radial direction and are in contact with the rice in the inner pot 7 and the non-separated from the rice in the inner pot 7 and the like. The state of stirring can be switched. That is, each of the first and second agitating bodies 26A and 26B has one end rotatably attached to the rotating body 25 and the other end separated from the rotating body 25 or attached to the rotating body 25. It is possible to approach. The first and second stirring bodies 26A and 26B are examples of “stirring bodies”.

FIG. 3 is a schematic view of the rotating body 25 viewed from the inner pot 7 side.
FIG. 4 is a schematic perspective view for explaining the stirring state of the first and second stirring bodies.

  With reference to FIG. 3 and FIG. 4, the rotating body 25 includes a lid body side member 27 and an inner pot side member 28 detachably attached to the surface of the lid body side member 27 on the inner pot 7 side. Yes. Between the lid-side member 27 and the inner pot-side member 28, the first and second agitator and umbrella gears 30, the first agitator gears 31A, 32A, and 33A, and the second agitator gear 31B, 32B and 33B are arranged. The rotational drive of the rotary shaft 29 is transmitted to the first agitator rotating shaft 34A via the first and second agitator / umbrella gears 30 and the first agitator gears 31A, 32A, 33A, It is transmitted to the second agitator rotating shaft 34B via the second agitator / umbrella gear 30 and the second agitator gears 31B, 32B, 33B. Thus, when the rotating shaft 29 rotates, the first and second stirring bodies 26A and 26B are rotated around the first and second stirring body rotating shafts 34A and 34B. It is possible to switch from the non-stirring state shown to the stirring state shown in FIG. 4 or from the stirring state to the non-stirring state.

  In addition, in FIG. 4, illustration of the rice cooker main body 1 and the cover body 2 is abbreviate | omitted so that 1st, 2nd stirring body 26A, 26B can be visually recognized.

FIG. 5 is a schematic top view of the rice cooker 100 as viewed from above.
Referring to FIG. 5, a liquid crystal display unit 5 and a plurality of operation switches 6 arranged so as to surround liquid crystal display unit 5 are provided on the front part of the upper surface of lid 2.

  The operation switch 6 includes a warm / cancel switch 6A, a dish selection switch 6B, a rice cooking selection switch 6C, a rice cooking / start switch 6D, a rice washing switch 6E, a reservation switch 6F, a downward switch 6G, and an upward direction. Switch 6H. The operation switches 6A to 6H are provided with LED indicators 61A to 61H, respectively.

  The heat retention / cancellation switch 6A is a switch for instructing the start of the heat retention or the cancellation of the started cooking or selected contents, and indicates that the heat retention state is present when the LED indicator 61A is lit.

  The dish selection switch 6B is a switch for selecting a cooking menu to be executed from the cooking menu stored in advance, and the cooking menu is selected in a predetermined order each time it is pressed. The LED indicator 61B is lit, indicating that the cooking menu has been selected.

  The rice cooking selection switch 6C is a switch for selecting a rice cooking menu to be executed from pre-stored rice cooking menus, and each time the button is pressed, the rice cooking menu is selected in a predetermined order. The LED indicator 61C is lit, indicating that the rice cooking menu is selected.

  The rice cooking / start switch 6D is a switch for instructing the start of the rice cooking menu, the cooking menu, and the rice washing menu, which will be described later. Etc.) is started. When the LED indicator 61D is lit, this indicates that the rice cooking menu, cooking menu, or rice washing menu is being executed.

  The rice washing switch 6E is a switch for selecting a rice washing menu which is an operation menu for washing the rice contained in the inner pot 7 with water. The LED indicator 61E is lit to indicate that the rice washing menu is selected.

  The reservation switch 6F is a switch for instructing the start reservation of the rice cooking menu, the cooking menu, the rice washing menu, and the like, and accepts the time (reservation time) until the start of the previously selected menu when pressed. It becomes a state. The fact that the LED indicator 61F is lit indicates that the start of the rice cooking menu, cooking menu, rice washing menu, etc. is reserved.

  The down direction switch 6G and the up direction switch 6H are switches for instructing to send the selected content and set time forward or backward (forward feed, backward feed). The LED indicators 61G and 61H are lit to indicate that a post-feed operation or a post-feed operation is being performed.

  FIG. 6 is an enlarged view of the liquid crystal display unit 5 and shows all characters and figures that can be displayed on the liquid crystal display unit 5.

  With reference to FIG. 6, the liquid crystal display unit 5 displays a rice display unit 5a for displaying the type of rice, a cooking method display unit 5b for displaying how to cook rice, and a cooking menu. The cooking display section 5c, the internal state display section 5d for displaying the stirring state in the inner pot 7 by the rotating body 25 and the first and second stirring bodies 26A, 26B, the time display section 5e, and the operation switch 6 And an operation state display unit 5f for displaying the operation state.

  As an example, the rice display unit 5a displays one of “white rice”, “washless rice”, “brown rice”, “germinated brown rice”, and “split rice”.

  As an example, the cooking method display portion 5b includes “rice”, “superior”, “oisagi”, “cooking”, “rice porridge”, “gomi-gayu”, “curry”, “small amount”, “grill” ”,“ Sushimeshi ”and“ Eco-cooked rice ”are displayed.

  As an example, the cooking display unit 5c displays one of “boiled food”, “stew”, “steamed food”, “confectionery”, “my menu”, “reservation 1”, and “reservation 2”.

  The display of the rice display unit 5a, the cooking method display unit 5b, and the cooking display unit 5c changes according to the operation of the operation switch 6.

  The display of the internal state display unit 5d changes according to the state of the rotating body 25 and the first and second stirring bodies 26A and 26B.

The display of the time display part 5e changes with progress of time or a cooking process.
The operation state display unit 5f displays that the operation with the operation switch 6 is in an invalid state. The liquid crystal display unit 5 is an example of a “notification unit”.

FIG. 7 is a schematic view of a cross section of the rice cooker 100 cut along a vertical plane.
Referring to FIG. 7, a rice cooker 100 is attached to the above rice cooker body 1, an inner pot 7 housed in the rice cooker body 1, and an upper portion of the rice cooker body 1 so as to be openable and closable. The lid 2 that can be closed to cover, the outer lid 21 that is located on the opposite side of the inner pan 7 when the lid 2 is closed, and the inner pan 7 side when the lid 2 is closed The inner lid 22 positioned, the lid heater 4a for heating the inner lid 22, the heat retaining heater 4b for retaining the heated object in the inner pan 7 by heating the side surface of the inner pan 7, and the rice cooker An induction coil 4c for inductively heating the inner pan 7, a temperature sensor 15a for detecting the temperature of the inner pan 7, and a heated object housed in the inner pan 7 A weight sensor 15b for detecting the weight and a rotating body 25 detachably attached to the lid body 2 are included. The inner pot 7, the lid heater 4a, the heat retaining heater 4, and the induction coil 4c are examples of a “heating chamber”.

  A stirring motor 24 is installed in the outer lid 21. A rotating shaft 29 of the rotating body 25 passes through the inner lid 22 and one end thereof is connected to the stirring motor 24 via a pulley or a belt (not shown).

  A liquid crystal display unit 5 and an operation switch 6 are provided on the surface of the outer lid 21. The outer lid 21 includes a main control unit that is connected to the liquid crystal display unit 5 and the operation switch 6 and controls the entire rice cooker 100 according to the operation. The main control unit includes a main CPU 10a and a storage unit such as a main ROM (Read Only Memory) 11a and a main RAM (Random Access Memory) 12a. Each unit included in the main control unit is mounted on the main board 70. A connector 17 a is further mounted on the main board 70. The main CPU 10a is an example of a “control circuit”.

  In addition, Hall ICs (Integrated Circuits) 56a and 56b and a connector 17b are provided at the front portion in the outer lid 21. The Hall ICs 56a and 56b and the connector 17b are mounted on the detection board 71. The detection board 71 is electrically connected to the main board 70 via the harness 17c. In the rice cooker body 1, a magnet 56c is disposed in the vicinity of a position facing the Hall ICs 56a and 56b when the lid 2 is closed.

  In the space between the rice cooker body 1 and the inner pot 7, a sub-control unit for receiving control signals from the main CPU 10a and controlling each part included in the rice cooker body 1 such as induction heating by the induction coil 4c. Is included. The sub control unit includes a sub CPU 10b and a storage unit such as a sub ROM 11b and a sub RAM 12b.

  A cooling fan 13 for cooling these heat generations is disposed in the vicinity of the sub-control unit and the induction coil 4c.

<Functional configuration>
FIG. 8 is a block diagram showing an outline of the configuration of the control system of the rice cooker 100.

  Referring to FIG. 8, the control system of rice cooker 100 is broadly divided into a main control system on the lid 2 side and a sub-control system on the rice cooker body 1 side. The main control system on the lid 2 side includes a main CPU 10a, and the sub control system on the rice cooker body 1 side includes a sub CPU 10b.

  In addition to controlling each function included in the main control system, the main CPU 10a outputs a control signal to the sub CPU 10b to cause the sub CPU 10b to control each function included in the sub control system. The sub CPU 10b outputs various signals to the main CPU 10a.

  The main CPU 10a and the sub CPU 10b are electrically separated (insulated). Therefore, the communication of the signal between the main CPU 10a and the sub CPU 10b preferably uses wireless communication. As an example, a photocoupler may be used. That is, the main control system and the sub control system each include communication units 54a and 54b and exchange the above signals. The communication units 54a and 54b preferably perform wireless communication, and a photo coupler is an example.

  The main control system includes a power supply circuit 50a, and the sub control system includes power supply circuits 50b and 50c. The AC power supplied from the commercial power source 470 via the power cord 47 (not shown) included in the rice cooker body 1 is provided to the power supply circuits 50b and 50c of the sub-control system.

  The sub-control system power supply circuit 50c converts the supplied AC power into DC power and supplies it to the sub CPU 10b. The sub-control system power supply circuit 50b is a power supply circuit for supplying power to the main control system. After the supplied AC power is converted into DC power, it is converted into AC power for supply to the main control system and insulated. Pass to the transformer 40. The AC power is transformed by the insulation transformer 40 and then input to the power circuit 50a of the main control system. The main control system power supply circuit 50a converts the input AC power into DC power and supplies it to the main CPU 10a. That is, the power supply circuit 50a and the power supply circuit 50b are electrically insulated by the insulating transformer 40, and transmit electric energy from the power supply circuit 50a to the power supply circuit 50b by electromagnetic induction.

  FIG. 9 is a block diagram showing details of the main control system in the control system configuration of FIG. For the sake of explanation, the configuration of the sub-control system is also illustrated.

  Referring to FIG. 9, the main control system includes a main CPU 10a. The main CPU 10a operates with power supplied from the power supply circuit 50a.

  The main CPU 10a is electrically connected to a main ROM 11a for storing a program executed by the main CPU 10a and a main RAM 12a serving as a work area for executing the program.

  The main CPU 10a further includes a communication unit 54a, a liquid crystal display unit 5, an operation switch 6, an LED indicator 61, a buzzer 14, a timer 16, an attachment / detachment detection unit 55, a motor drive circuit 57, and a lid open / close detection unit 56. It is connected.

  The main CPU 10a selects and executes a corresponding program by receiving an operation signal input from the operation switch 6. The main CPU 10a controls the display on the liquid crystal display unit 5, lighting / extinguishing of the LED indicator 61, and ringing of the buzzer 14 by executing a program. Moreover, the control signal for controlling the structure used as a control object based on execution of the said program among each part contained in a sub control system is passed to the communication part 54a, and it outputs with respect to sub CPU10b.

  The motor drive circuit 57 is a mechanism for driving the agitation motor 24. The main CPU 10a controls the motor drive circuit 57 so as to drive the agitation motor 24 at a necessary timing and at a necessary drive amount in accordance with the execution of the program. Note that a detection signal from a lid opening / closing detection unit 56 described later may also be input to the motor drive circuit 57, and the agitation motor 24 may be driven / not driven in response to the detection signal. The motor drive circuit 57 is an example of a “drive unit”, and the stirring motor 24, the rotating body 25 (see FIG. 3), and the stirring body 26 are examples of a “driven body”.

  The attachment / detachment detection unit 55 is a mechanism for detecting attachment / detachment of the rotating body 25 configured to be attachable / detachable to / from the lid body 2. Although the specific configuration is not limited to a specific configuration, as an example, the amount of rotation is determined based on the pulse signal of the agitation motor 24 that transmits power to the rotation shaft 29 of the rotating body 25, and the rotating body 25. The structure which detects attachment / detachment of a is mentioned. As another configuration, for example, a sensor for detecting attachment / detachment may be used.

  The lid open / close detection unit 56 is a mechanism for detecting the open / closed state of the lid 2 with respect to the rice cooker body 1. The lid opening / closing detection unit 56 will be described in detail later with reference to FIG.

  In addition to the configuration of FIG. 9, a mechanism for detecting the state (stirring state, non-stirring state) of the stirring body 26 with respect to the rotating body 25 may be included. The configuration of this mechanism is not limited to a specific configuration. For example, a sensor may be used, and the state of the stirring body 26 may be determined by determining the rotation amount based on the pulse signal of the stirring motor 24. May be detected.

These detection signals are input to the main CPU 10a and used for control as necessary.
FIG. 10 is a block diagram showing details of a sub-control system in the control configuration of FIG. For the sake of explanation, the structure of the main control system is also shown.

  Referring to FIG. 10, the sub control system includes a sub CPU 10b. The sub CPU 10b operates by receiving power supply from the power supply circuit 50c.

  The sub CPU 10b includes a synchronization detection unit 43, an IGBT (Insulated Gate Bipolar Transistor) 45, a current transformer 59, relays 51a and 51b, an oscillation circuit 52 for generating a pulse signal, a lid lock drive unit 44, A fan drive circuit 58, a temperature detection circuit 41, and a reset circuit 53 for performing reset control are electrically connected.

  The power line from the commercial power source 470 is connected to the rectifier circuit 48 via the relay 51c. A current transformer 59 is inserted and connected to the power line connecting the commercial power source 470 and the rectifier circuit 48. The current transformer 59 is arranged between the connection node between the power line and the diodes D1 and D2 and the connection node between the power line and the rectifier circuit 48, detects a current flowing through the power line, and outputs the detected value to the sub CPU 10b.

  The rectifier circuit 48 includes four diodes (not shown) connected in a bridge, and full-wave rectifies the AC voltage from the commercial power source 470. The rectifier circuit 48 outputs the rectified DC power to a smoothing circuit including a choke coil and a capacitor 49. The smoothing circuit smoothes the rectified DC power and supplies it to the parallel circuit of the induction coil 4 c and the resonance capacitor 46.

  The IGBT 45 constitutes a “power control element” for controlling the power supplied to the induction coil 4 c. A diode D3 is connected to the IGBT 45 in antiparallel. An IGBT is exemplified as the power control element, but a power switching element such as a power MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) may be used.

  The IGBT 45 switches between supply and interruption of power to the induction coil 4c by turning on / off in response to a control signal from the sub CPU 10b. Specifically, when the IGBT 45 is turned on, power is supplied from the rectifier circuit 48 to the induction coil 4c. When the IGBT 45 is turned off, a current flows in the resonance circuit including the induction coil 4 c and the resonance capacitor 46. The inner pot 7 is induction-heated in a state where resonance occurs in the resonance circuit.

  Furthermore, the power line from the commercial power source 470 is connected to the lid heater 4a and the heat retaining heater 4b via the diodes D1 and D2, and power is supplied to these heaters. Relays 51a and 51b are connected to a power supply path to the lid heater 4a and the heat retaining heater 4b. Relays 51a and 51b are turned ON / OFF in response to a control signal from sub CPU 10b. The relays 51a and 51b constitute an “opening / closing device” capable of interrupting the power supply path to the lid heater 4a and the heat retaining heater 4b.

  A communication unit 54b is further electrically connected to the sub CPU 10b. The communication unit 54b receives a control signal from the main CPU 10a and controls each unit according to the control signal. At this time, the sub CPU 10b may read the program stored in the sub ROM 11b and execute it while developing it in the sub RAM 12b.

  That is, the sub CPU 10b controls heating of the induction coil 4c by controlling ON / OFF of the IGBT 45 in accordance with a control signal from the main CPU 10a. At this time, the synchronization detection unit 43 extracts a synchronization signal from the AC power supplied from the commercial power supply 470 and inputs it to the sub CPU 10b. The sub CPU 10b controls ON / OFF of the IGBT 45 at a timing based on the synchronization signal.

  Further, the sub CPU 10b controls the heating and heat retention in the lid heater 4a and the heat retaining heater 4b by controlling ON / OFF of the relays 51a and 51b in accordance with a control signal from the main CPU 10a.

  The lid lock drive unit 44 is a mechanism for driving the lid lock unit 9, and the sub CPU 10b controls the lid lock drive unit 44 to lock / unlock the lid lock unit 9 according to a control signal from the main CPU 10a.

  The fan drive circuit 58 is a mechanism for driving the cooling fan 13, and the sub CPU 10b controls the fan drive circuit 58 to drive the cooling fan 13 in accordance with a control signal from the main CPU 10a.

  The temperature detection circuit 41 is a mechanism for detecting the temperature in the inner pot 7, detects the temperature based on the sensor signal from the temperature sensor 15a, and inputs the detection signal to the sub CPU 10b.

  The relay 51c cuts off the supply of power supplied from the commercial power source 470 to the lid heater 4a, the heat retaining heater 4b, and the induction coil 4c. The exciting coil of the relay 51c is connected to the main CPU 10a of the main control system. When power is supplied from the main CPU 10a to the exciting coil, the contact of the relay 51c is closed (OFF). When the exciting coil is not energized, the contact is opened (ON) to the relay 51c. That is, the main CPU 10a of the main control system can perform control for directly shutting off the supply of power to the lid heater 4a, the heat retaining heater 4b, and the induction coil 4c according to the program to be executed.

<Overview of operation>
FIG. 11 is a circuit diagram showing details of the lid opening / closing detection unit 56 of FIG.

  Referring to FIG. 11, lid opening / closing detection unit 56 includes a main CPU 10a, Hall ICs 56a and 56b, a connection unit 17, a pull-up circuit 18a, and a pull-down circuit 18b.

  Hall ICs 56a and 56b detect the open and closed states of lid 2 and output signals. When the lid 2 is in the open state, the potential of the signal is at a high level. When the lid 2 is in a closed state, the potential of the signal is at a low level. That is, in the present embodiment, the lid 2 being in the open state corresponds to the “first state” of the lid, and the lid 2 being in the closed state is the “second state” of the lid. Corresponding to The Hall IC 56a is an example of a “first detection unit”, and the Hall IC 56b is an example of a “second detection unit”.

  The connection unit 17 electrically connects each of the Hall ICs 56a and 56b and the main CPU 10a. The connection part 17 includes connectors 17a and 17b and a harness 17c.

  The main CPU 10a receives the signal from the Hall IC 56a as the detection signal s1 (first detection signal), and receives the signal from the Hall IC 56b as the detection signal s2 (second detection signal). Based on the detection signals s1 and s2, the main CPU 10a determines whether the lid 2 is in an open state or a closed state. This corresponds to the control circuit determining whether the lid is in the first state or the second state.

  The pull-up circuit 18a is provided in the transmission path of the detection signal s1 between the connection unit 17 and the main CPU 10a. Pull-up circuit 18a includes a pull-up resistor R1. When the transmission of the detection signal s1 is interrupted, the pull-up circuit 18a pulls up the potential of the transmission path of the detection signal s1 to a high level (potential Vdd).

  The pull-down circuit 18b is provided in the transmission path of the detection signal s2 between the connection unit 17 and the main CPU 10a. The pull-down circuit 18b includes a pull-down resistor R2. When the transmission of the detection signal s2 is interrupted, the pull-down circuit 18b pulls down the potential of the transmission path of the detection signal s2 to a low level (potential Vss).

  There are a total of four combinations of potentials of the detection signals s1 and s2. For each of these four combinations, the main CPU 10a determines as follows.

  Regarding the first combination, when the potentials of the detection signals s1 and s2 are both high, the main CPU 10a determines that the lid body 2 is in the open state.

  Regarding the second combination, when the potentials of the detection signals s1 and s2 are both at a low level, the main CPU 10a determines that the lid 2 is in a closed state.

  With respect to the third combination, when the potential of the detection signal s1 is high and the potential of the detection signal s2 is low, the main CPU 10a determines that a problem has occurred in the connection state of the connection unit 17. . The malfunction in the connection state of the connection unit 17 refers to a state in which the Hall ICs 56a and 56b and the main CPU 10a are not electrically connected. As this factor, for example, it is conceivable that the connection failure of the connectors 17a and 17b or at least one of the connectors 17a and 17b is disconnected due to an impact generated each time the lid 2 is opened and closed.

  Regarding the fourth combination, when the potential of the detection signal s1 is low and the potential of the detection signal s2 is high, the main CPU 10a has a problem with at least one of the Hall ICs 56a and 56b. Judge.

  The first and second combinations are judgments at normal times. The third and fourth combinations are judgments when a failure occurs. The reason why the above determination can be made for the third combination will be described.

  It is assumed that the lid body 2 is in an open state. Each of the Hall ICs 56a and 56b detects that the lid 2 is open and outputs a signal. The potentials of these signals are all at a high level. The main CPU 10a receives the signal from the Hall IC 56a as the detection signal s1, and receives the signal from the Hall IC 56b as the detection signal s2. Since the potentials of the detection signals s1 and s2 are both high, the main CPU 10a determines that the lid 2 is open.

  When a failure occurs in the connection state of the connection unit 17 (for example, the connection of the connector 17a is disconnected), both the detection signal s1 is transmitted from the Hall IC 56a to the main CPU 10a and the detection signal s2 is transmitted from the Hall IC 56b to the main CPU 10a. Disappears. The potential of the transmission path of the detection signal s1 is pulled up to a high level by the pull-up circuit 18a. That is, the potential of the detection signal s1 does not change from the high level. On the other hand, the potential of the transmission path of the detection signal s2 is pulled down to a low level by the pull-down circuit 18b. That is, the potential of the detection signal s2 is switched from the high level to the low level. Therefore, the main CPU 10 a can determine that a problem has occurred in the connection state of the connection unit 17.

  The same applies to the case where the lid 2 is in the closed state. Initially, the potentials of the detection signals s1 and s2 are both at a low level. When a problem occurs in the connection state of the connection unit 17, the potential of the transmission path of the detection signal s1 is pulled up to a high level by the pull-up circuit 18a. On the other hand, the potential of the transmission path of the detection signal s2 is pulled down to a low level by the pull-down circuit 18b. Therefore, the main CPU 10 a can determine that a problem has occurred in the connection state of the connection unit 17.

  For comparison with the present embodiment, a case where a pull-up circuit (not shown) is provided in the transmission path of the detection signal s2 instead of the pull-down circuit 18b will be described. That is, a pull-up circuit is provided in each transmission path of the detection signals s1 and s2.

  It is assumed that the lid body 2 is in an open state. The potentials of the detection signals s1 and s2 are both high level. When a failure occurs in the connection state of the connection unit 17, the transmission of the detection signals s1 and s2 is interrupted. However, the potentials of the transmission paths for the detection signals s1 and s2 are both pulled up. For this reason, the potentials of the detection signals s1 and s2 do not change from the high level. Therefore, even if a problem occurs in the connection state of the connection unit 17 when the lid 2 is in the open state, the main CPU 10a cannot determine that fact.

  Next, it is assumed that the lid 2 is in a closed state. The potentials of the detection signals s1 and s2 are both low level. When a failure occurs in the connection state of the connection unit 17, the transmission of the detection signals s1 and s2 is interrupted. The potentials of the transmission paths for the detection signals s1 and s2 are both pulled up. Therefore, the potentials of the detection signals s1 and s2 are both switched from the low level to the high level. Therefore, the main CPU 10a determines that the lid 2 has been opened. That is, even if a failure occurs in the connection state of the connection portion 17 when the lid body 2 is in the closed state, the lid body 2 switches from the closed state to the open state, whether a failure occurs in the connection state of the connection portion 17. The main CPU 10a cannot determine whether it has occurred.

  Also in the case where a pull-down circuit is provided in each transmission path of the detection signals s1 and s2, if the potential of the detection signals s1 and s2 and the open state and the closed state of the lid 2 are interchanged, they are exactly the same as the above case. is there. Therefore, detailed description will not be repeated.

  In the above, the case where a malfunction has occurred in both of the transmission paths of the detection signals s1 and s2 has been described. However, the third combination similarly occurs when a failure occurs in only one of the transmission paths of the detection signals s1 and s2. When a failure occurs only in the transmission path of the detection signal s1, the transmission of the detection signal s1 is interrupted. For this reason, the potential of the detection signal s1 is fixed to a high level by the pull-up circuit 18a. On the other hand, the potential of the transmission path of the detection signal s2 is switched between a high level and a low level as the lid 2 is opened and closed. Therefore, when the lid body 2 is in the closed state, the potential of the transmission path of the detection signal s2 is at a low level. Thus, a third combination occurs. On the contrary, the same applies to the case where a failure occurs only in the transmission path of the detection signal s2, and thus the detailed description will not be repeated.

  Next, the reason why the above determination can be made regarding the fourth combination will be described. In this combination, there is no problem in the connection state of the connection portion 17. This is because the potential of the detection signals s1 and s2 becomes the third combination when a problem occurs in the connection state of the connection unit 17. The possibility of the Hall ICs 56a and 56b may be considered as other locations where the malfunction occurs.

  More specifically, when the lid 2 is in the open state, the potentials of the detection signals s1 and s2 must be at a high level. However, the potential of the detection signal s1 is at a low level. For this reason, it is considered that a defect has occurred in the Hall IC 56a. On the other hand, when the lid 2 is in the closed state, the potentials of the detection signals s1 and s2 must both be at a low level. However, the potential of the detection signal s2 is high level. For this reason, it is considered that a defect has occurred in the Hall IC 56b. The lid opening / closing detection unit 56 is an example of a “lid opening / closing detection circuit”.

<Operation flow>
FIG. 12 is a flowchart illustrating an example of a determination flow when the main CPU 10a receives a detection signal.

  Referring to FIG. 12, in step S1, main CPU 10a receives detection signals s1 and s2. The main CPU 10a determines whether the potential of each of the detection signals s1 and s2 is high level or low level.

  In step S2, the main CPU 10a determines whether or not the potentials of the detection signals s1 and s2 are at a high level. If the main CPU 10a determines that the potentials of the detection signals s1 and s2 are both high, the process proceeds to step S21. In this case, the main CPU 10a determines that the lid 2 is in the open state.

  On the other hand, if the main CPU 10a determines that at least one of the potentials of the detection signals s1 and s2 is not at the high level, the process proceeds to step S3.

  In step S3, the main CPU 10a determines whether or not the potentials of the detection signals s1 and s2 are both at a low level. If the main CPU 10a determines that the potentials of the detection signals s1 and s2 are both low, the process proceeds to step S31. In this case, the main CPU 10a determines that the lid 2 is in the closed state.

  On the other hand, if the main CPU 10a determines that at least one of the potentials of the detection signals s1 and s2 is not at a low level, the process proceeds to step S4.

  In step S4, the main CPU 10a determines whether or not the potential of the detection signal s1 is at a high level and the potential of the detection signal s2 is at a low level. If the main CPU 10a determines that the potential of the detection signal s1 is high and the potential of the detection signal s2 is low, the process proceeds to step S41. In this case, the main CPU 10a determines that the connection state of the connection unit 17 is defective.

  On the other hand, when the main CPU 10a determines that the potentials of the detection signals s1 and s2 are not the above combination (that is, the potential of the detection signal s1 is low level and the potential of the detection signal s2 is high level), the processing is performed. Proceed to step S42. In this case, the main CPU 10a determines that at least one of the Hall ICs 56a and 56b has a problem.

  Control in the case where the main CPU 10a determines that a failure has occurred in any part of the lid opening / closing detection unit 56 in steps S41 and S42 will be described.

  The main CPU 10a notifies the user to that effect by the liquid crystal display unit 5 (see FIG. 6). Specifically, the main CPU 10a controls the liquid crystal display unit 5 so as to display, for example, an error code indicating a position where the malfunction of the lid opening / closing detection unit 56 occurs on the time display unit 5e. The user who sees the error code can take a response such as requesting a repairer (for example, the manufacturer of the rice cooker 100) to repair. The repair shop can easily identify the location where the failure occurs by using the error code. Therefore, the time required for repair can be shortened.

  It is more preferable to display different error codes when a failure occurs in the connection state of the connection unit 17 (step S41) and when a failure occurs in at least one of the Hall ICs 56a and 56b (step S42). . This makes it easier for the repairer to identify the location where the malfunction occurred. Instead of the liquid crystal display unit 5, a dedicated LED indicator (not shown) may be provided. Further, this may be notified by voice using the buzzer 14 or the like.

  Even when it is determined that a problem has occurred in the lid opening / closing detection unit 56, the main CPU 10a can control the lid heater 4a, the heat retaining heater 4b, and the induction coil 4c so as to stop heating. Thereby, it can prevent more reliably that it heats by said each part when the cover body 2 is an open state. Note that the main CPU 10a may control only a part of the lid heater 4a, the heat retaining heater 4b, and the induction coil 4c to stop heating.

  Each of the third and fourth combinations has been described in the embodiment as being caused by a single cause. However, there may be multiple causes for the occurrence of each of the third and fourth combinations.

  FIG. 13 is a diagram illustrating combinations of potentials of the detection signals s1 and s2 and causes that may cause each of the combinations in the lid opening / closing detection circuit illustrated in FIG.

  Referring to FIG. 13, the first and second combinations are similar to the description of FIG. 12, and thus the detailed description will not be repeated.

  Regarding the third combination, when the potential of the detection signal s1 is high level and the potential of the detection signal s2 is low level, the main CPU 10a determines that the location where the failure occurs is the connection state of the connection unit 17. This has been described with reference to FIG. However, the possibility of the occurrence of the defect being at least one of the Hall ICs 56a and 56b is also considered as a cause of the occurrence of the third combination.

  Specifically, when the lid 2 is in the open state, the potentials of the detection signals s1 and s2 are both high. However, if a malfunction occurs in the Hall IC 56b, the potential of the detection signal s2 may become low level. Similarly, when the lid 2 is in the closed state, the potentials of the detection signals s1 and s2 are both at a low level. However, when a malfunction occurs in the Hall IC 56a, the potential of the detection signal s1 may become a high level.

  In this case, the CPU 10a may cause the liquid crystal display unit 5 to display an error code indicating that the location where the failure occurs is at least one of the connection state of the connection unit 17 and the Hall ICs 56a and 56b. When the repairer who sees this error code investigates the connection state of the connecting portion 17 and finds no malfunction, the repair company may determine that the location of the malfunction is at least one of the Hall IC 56a and the Hall IC 56b. it can. Therefore, there is a high possibility that the location where the defect occurs can be specified.

  Subsequently, with respect to the fourth combination, when the potential of the detection signal s1 is low level and the potential of the detection signal s2 is high level, the main CPU 10a determines that the failure occurs as the Hall ICs 56a and 56b. This has been described with reference to FIG. However, for example, the possibility that the main CPU 10a detects a potential of the detection signals s1 and s2 due to a problem with an input terminal (not shown) of the main CPU 10a is also considered as a cause of the fourth combination.

  Specifically, a failure occurs in the input terminal that receives the detection signal s1, while the transmission path of the detection signal s2 is normal. In this case, when the lid 2 is in the open state, the potential of the detection signal s1 is at a high level. However, since a problem has occurred in the input terminal that receives this signal, the main CPU 10a determines that the potential of the detection signal s1 is at a low level. Note that the same applies to the case where the input terminal that receives the detection signal s2 has a defect and the lid 2 is in the closed state, and thus detailed description will not be repeated.

  In this case, the CPU 10a may cause the liquid crystal display unit 5 to display an error code indicating that the location of occurrence of the malfunction is one of the detection of the potentials of the detection signals s1 and s2 by the Hall ICs 56a and 56b and the main CPU 10a. The repairer who has seen this error code may determine that the location of the failure is the detection of the potentials of the detection signals s1 and s2 by the main CPU 10a if there is no failure by examining the Hall ICs 56a and 56b. it can. Therefore, there is a high possibility that the location where the defect occurs can be specified.

  As described above, when the potentials of the detection signals s1 and s2 are different from each other (third and fourth combinations), the main CPU 10a determines that a problem has occurred in the detection of the open state and the closed state of the lid body 2. To do. In addition, when the potential of the detection signal s1 is high level and the potential of the detection signal s2 is low level (third combination), the main CPU 10a determines the connection state of the connection unit 17 and the Hall IC 56a. , 56b is determined to be a defect occurrence location. On the other hand, when the potential of the detection signal s1 is low level and the potential of the detection signal s2 is low level (fourth combination), the main CPU 10a is connected to the input terminals of the Hall ICs 56a and 56b and the main CPU 10a. It is determined that at least one of them is a defect occurrence location. Thereby, it is possible to identify the location where the problem occurs.

  In addition, it demonstrated using Hall IC as a 1st and 2nd detection part. However, these detection units may be anything as long as they detect the open state and the closed state of the lid body 2 and output detection signals. The detection unit may detect the open state and the closed state of the lid 2 electrically or optically. Further, a mechanical mechanism for detecting the open state and the closed state of the lid 2 may be provided. Or you may detect the vibration or impact at the time of the cover body 2 opening and closing.

  Although the open state of the lid body 2 corresponds to the first state of the lid body and the closed state of the lid body 2 corresponds to the second state of the lid body, these correspondence relationships may be interchanged.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 Rice cooker body, 2 lid, 2a steam outlet, 3 open button, 4a lid heater, 4b warming heater, 4c induction coil, 5 liquid crystal display, 6, 6A-6H operation switch, 7 inner pan, 8 engaged Stop part, 9 Lid lock part, 10a main CPU, 10b sub CPU, 11a main ROM, 11b sub ROM, 12a main RAM, 12b sub RAM, 13 cooling fan, 14 buzzer, 15a temperature sensor, 15b weight sensor, 16 timer, 17 connection part, 17a, 17b connector, 17c harness, 18a pull-up circuit, 18b pull-down circuit, 21 outer lid, 22 inner lid, 23 locking part, 24 stirring motor, 25 rotating body, 26 stirring body, 27 lid body side member 228 Inner pan side member, 29 Rotating shaft, 30 Stirrer combined umbrella gear, 31A, 32A, 33A First stirrer gear, 31B, 32B, 33B Second stirrer gear, 34A First stirrer rotating shaft, 34B Second stirrer rotating shaft, 40 Insulation transformer, 41 Temperature detection circuit, 42 , 51a, 51b Relay, 43 Sync detection unit, 44 Lid lock drive unit, 45 IGBT, 46, 49 Capacitor, 47 Power cord, 48 Rectifier circuit, 50a, 50b, 50c Power circuit, 52 Oscillator circuit, 53 Reset circuit, 54a , 54b communication unit, 55 attachment / detachment detection unit, 56 lid open / close detection unit, 56a, 56b Hall IC, 57 motor drive circuit, 58 fan drive circuit, 59 current transformer, 61, 61A to 61H LED indicator, 70 main board, 71 detection Substrate, 100 rice cooker, 470 commercial power supply, s1, s2 detection signal, R1 pull-up resistor , R2 pull-down resistor.

Claims (9)

An open / close detection circuit used in an electric device including a main body and a lid attached to the main body so as to be openable / closable,
Each detects an open state and a closed state of the lid, and outputs a signal. When the lid is in a first state corresponding to one of the open state and the closed state, the signal is output. The first and second potentials of the signal are at a low level when the potential of the signal is at a high level and the lid is in a second state corresponding to the other of the open state and the closed state The detector of
The first detection unit receives the signal from the first detection unit as a first detection signal, receives the signal from the second detection unit as a second detection signal, and the lid body is in the first and second states. A control circuit for determining which one of
A connection part for electrically connecting each of the first and second detection parts and the control circuit;
Provided in the transmission path of the first detection signal between the connection unit and the control circuit, and when the transmission of the first detection signal is interrupted, the potential of the transmission path of the first detection signal A pull-up circuit for pulling up to a high level;
Provided in the transmission path of the second detection signal between the connection unit and the control circuit, and when the transmission of the second detection signal is interrupted, the potential of the transmission path of the second detection signal And a pull-down circuit that pulls down to the low level,
The control circuit determines that the lid is in the first state when the potentials of the first and second detection signals are both at the high level;
When the potentials of the first and second detection signals are both at the low level, it is determined that the lid is in the second state;
An open / close detection circuit that determines that a failure has occurred in detecting the open state and the closed state of the lid when the potentials of the first and second detection signals are different from each other.   In the control circuit, when the potential of the first detection signal is at the high level and the potential of the second detection signal is at the low level, a failure has occurred in the connection state of the connection portion. The open / close detection circuit according to claim 1, wherein:   The control circuit is configured to detect the first detection signal and the second detection unit when the potential of the first detection signal is the low level and the potential of the second detection signal is the high level. The open / close detection circuit according to claim 1, wherein it is determined that a failure has occurred in at least one of them.   The control circuit is configured to detect the first detection signal and the second detection unit when the potential of the first detection signal is the high level and the potential of the second detection signal is the low level. The open / close detection circuit according to claim 1, wherein it is determined that a failure has occurred in at least one of them.   When the potential of the first detection signal is at the low level and the potential of the second detection signal is at the high level, the control circuit performs the first and the second by the control circuit. The open / close detection circuit according to claim 1, wherein it is determined that a failure has occurred in detecting the potential of the detection signal. The body portion;
The lid;
An electric device comprising the open / close detection circuit according to claim 1. The electrical device further includes a notification unit for notifying the user of the occurrence location of the malfunction of the electrical device,
The electrical device according to claim 6, wherein the control circuit controls the notifying unit so as to notify a user to that effect when it is determined that the malfunction has occurred in the open / close detection circuit. The electric device further includes a heating chamber for accommodating the object to be heated and heating the object to be heated.
The heating chamber is provided inside the main body so as to be opened and closed by the lid body,
The said control circuit is an electric equipment of Claim 6 which controls the said heating chamber so that heating may be stopped, when it is judged that the said malfunction has generate | occur | produced in the said opening-and-closing detection circuit. The electrical equipment is
A drive unit controlled by the control circuit;
And a driven body driven by the driving unit,
The driven body is provided inside the main body so as to be opened and closed by the lid body,
The electrical device according to claim 6, wherein the control circuit controls the drive unit to stop driving the driven body when it is determined that the malfunction has occurred in the open / close detection circuit.

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