JP2013133962A - Heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely cut off power supply to heating means by causing a power switch of a capacitance type touch key to operates even in a use environment in which a microcomputer runs away owing to external noise etc.SOLUTION: A power supply switch conversion circuit 6 converts capacitance changing by touching a power switch 5 with a finger into voltage change and outputs it, a differentiating circuit 7 outputs the positive and negative and quantity of the output voltage change, and a comparing amplifier circuit 8 outputs an H/L signal based upon which of the input from the differentiating circuit 7 and a predetermined value is larger. A power supply state switching circuit 9 switches a power-ON state and a power-OFF state based upon the input from the comparing amplifier circuit 8 to supply driving electric power to a power supply relay 2 in the power-ON state and to cut off the supply of the driving electric power to the power supply relay 2 in the power-OFF state, thereby securing cutting off the power supply to heating means 3 since the power switch operates even in the use environment in which the microcomputer runs away owing to external noise.

Description

  The present invention relates to a heating cooker used for a general kitchen or business use.

  In recent years, this type of cooking device, particularly induction cooking devices, has been recognized and has been widely used because of its excellent features of safety, cleanliness, and high efficiency. Among them, a capacitance type touch key is provided on the top plate on the upper surface of the device, the capacitance between the touch key and the ground is converted to a DC voltage, and the relative change of the DC voltage is performed by software processing such as a microcomputer. Is detected to detect that a finger touches a touch key (see, for example, Patent Document 1).

  Furthermore, both the power switch for turning on and off the main power supply and the heating related switch for instructing the output of the heating means are configured by a capacitance type touch key, and that the finger touches the power switch by software processing such as a microcomputer. There are also means for separately providing means for detecting and means for detecting that a finger touches the heating-related switch by software processing such as a microcomputer (for example, see Patent Document 2).

JP 2006-121168 A JP 2010-261656 A

  However, in the conventional configuration, the power switch is configured with a capacitive touch key, and it detects that the power switch is touched by software processing of the microcomputer or the like, so the microcomputer runs away due to external noise or the like. Under such a use environment, the power switch is not useful, and there is a problem that the energization to the heating means cannot be interrupted in an emergency.

  An object of the present invention is to solve the above-described conventional problem, and to detect the on / off of a power switch, which is a capacitive touch key, without using a means involving software processing and to cut off the power supply to the heating means. And

  In order to solve the above-described conventional problems, a heating cooker according to the present invention includes a power relay that opens and closes a connection between a power source and a heating unit, a drive power source that opens and closes a contact of the power relay, and a top plate. A power switch that is an electrostatic capacitance type touch key composed of electrodes, a power switch conversion circuit that converts a capacitance that changes when a finger touches the power switch into a voltage change, and the power switch conversion circuit From the differential circuit that detects and outputs the positive and negative voltage changes and the amount of change, and the comparison amplification circuit that outputs an H / L signal based on the magnitude of the input from the differentiation circuit and a predetermined value, and the comparison amplification circuit The power supply is switched between a power-on state and a power-off state based on the input, and the power supply relay and the driving power supply are connected in the power-on state, and the power supply is in the power-off state. In the configuration including the power supply state switching circuit that cuts off the connection between the relay and the drive power supply, the comparison amplifier circuit has a polarity and a change amount when a signal input from the differentiation circuit touches the power switch. When the output logic is inverted when it is larger than the first predetermined value, and when the signal input from the differentiating circuit has the polarity when the finger is released from the power switch and the variation is larger than the second predetermined value The output logic is restored.

  As a result, the power switch conversion circuit → differentiation circuit → comparison amplifier circuit → power supply state switching circuit can be used to place the finger on the power switch, which is a capacitive touch key, when the power is on, without using a means involving software processing. When touched, the connection between the power relay and the drive circuit is cut off, and the contact of the power relay is opened.

  The heating cooker of the present invention uses a capacitive touch key for the power switch to improve the design of the device, and the power switch works well even in a usage environment where the microcomputer runs away due to external noise etc. The energization to the heating means can be reliably cut off, and the safety of the device can be improved.

The block diagram of the heating cooker in Embodiment 1 of this invention The figure which shows the power switch conversion circuit 6 similarly The figure which shows the differentiation circuit 7 same as the above The figure which shows the comparison amplifier circuit 8 same as the above The figure which shows the power supply state switching circuit 9 similarly Figure showing input / output timing of each circuit

  According to a first aspect of the present invention, there is provided a heating means, a power supply relay for opening / closing a connection between a power supply and the heating means, a driving power supply for opening / closing a contact of the power supply relay, a top plate, and an electrode provided on the top plate A power switch that is a capacitive touch key composed of a power switch, a power switch conversion circuit that converts a capacitance that changes when a finger touches the power switch into a voltage change, and an input from the power switch conversion circuit A differential circuit that detects and outputs the positive and negative voltage changes and the amount of change, a comparison amplifier circuit that outputs an H / L signal based on the magnitude of an input from the differential circuit and a predetermined value, and an input from the comparison amplifier circuit The power supply on state and the power supply off state are alternately switched based on the power supply state, the power supply relay and the driving power supply are connected in the power supply on state, and the power supply in the power supply off state. In the configuration provided with a power supply state switching circuit for cutting off the connection between the power supply and the drive power supply, the comparison amplifier circuit has a polarity and a change amount when a signal input from the differentiation circuit touches the power switch. When the output logic is inverted when it is larger than the first predetermined value, and when the signal input from the differentiating circuit has the polarity when the finger is released from the power switch and the variation is larger than the second predetermined value By returning the output logic to the original state, when the power switch is touched when the power switch is turned on by the power switch conversion circuit → differential circuit → comparison amplifier circuit → power state switching circuit, the power relay and the drive circuit Even if the microcomputer runs away due to external noise, etc., the power supply can be disconnected without using software processing means. Switch can be reliably cut off the power supply to the heating means clever.

  In a second aspect of the invention, particularly in the first aspect of the invention, the power supply state switching circuit inverts the input logic from the comparison amplifier circuit when the power supply is in an off state and then returns to the original state when the power supply relay is restored. When the power supply is in the power-off state, the connection between the power relay and the drive power supply is cut off immediately after the input logic from the comparison amplifier circuit is inverted. Even if an object is placed on the power switch or if water is spilled and the power switch is in the same situation as when a finger touches the power switch, the power status switching circuit Until the spilled water is wiped off, the connection between the power supply relay and the driving power supply is kept disconnected, and the power supply to the heating means is kept off, thereby improving the safety of the product.

  In a third aspect of the invention, particularly in the second aspect of the invention, when the power switch is in a power-off state, a finger touches the power switch, and the input logic from the comparison amplifier circuit to the power state switching circuit is inverted. By prohibiting acceptance of an operation for starting energization to at least the heating means, an object is placed on the power switch when the power is off, or water is spilled on the power switch. Even if the situation is similar to when a finger is touched, it is prohibited to accept an operation to start energizing the heating means until the object is removed from the power switch or the spilled water is wiped off. Can improve the safety.

  In a fourth aspect of the invention, particularly in the first to third aspects of the invention, the first predetermined value is smaller when the contact of the power supply relay is closed than when the contact of the power supply relay is open. By doing so, the acceptance sensitivity of the power switch when the contact of the power relay is closed and the heating means is energized, the acceptance sensitivity of the power switch when the contact of the power relay is open and the heating means is not energized It is better than the reception sensitivity and prevents the power switch reception sensitivity from becoming dull due to noise when the heating means composed of the means for induction heating is energized, or the electric field strength near the radio tower is reduced. In high areas, it is possible to prevent a phenomenon in which the power relay can be closed but cannot be opened by operating the power switch.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.
(Embodiment 1)
FIG. 1 is a block diagram of a heating cooker according to Embodiment 1 of the present invention.

  FIG. 2 is a diagram showing the power switch conversion circuit 6.

  FIG. 3 is a diagram showing the differentiating circuit 7.

  FIG. 4 is a diagram showing the comparison amplifier circuit 8.

  FIG. 5 is a diagram showing the power supply state switching circuit 9.

  FIG. 6 is a diagram showing the input / output timing of each circuit.

  As shown in FIG. 1, the heating cooker according to Embodiment 1 of the present invention connects a commercial power source 1 and a heating means 3 via a power relay 2.

  The heating means 3 includes a heating coil 3a and an inverter circuit 3b. The switching element in the inverter circuit 3b is turned on and off, a high frequency current of several tens kHz is applied to the heating coil 3a, and the heating coil 3a is magnetically coupled to the heating coil 3a. The pot 22 placed on the top plate 4 is induction-heated.

  The power switch conversion circuit 6 converts the capacitance change of the power switch 5 that is a capacitive touch key arranged on the top plate 4 into a DC voltage change and outputs it.

  The differentiation circuit 7 detects and outputs the positive / negative and change amount of the DC voltage change input from the power switch conversion circuit 6.

  The comparison amplifier circuit 8 detects that the DC voltage change input from the differentiating circuit 7 is negative and the amount of change is larger than ΔV1, inverts the output signal from L → H, and then inputs from the differentiating circuit 7. It detects that the DC voltage change is positive and the change amount is larger than ΔV2, and returns the output signal from H → L.

  The power supply state switching circuit 9 has three states, a power-off state, a power-on state (power switch 5 on), and a power-on state (power switch 5 off), and two outputs of an F signal and an L signal. It is detected that the signal input from the comparison amplifier circuit 8 is inverted from L to H in the state, and the power is turned on (power switch 5 is turned on). Thereafter, the signal input from the comparison amplifier circuit 8 is H → When the signal returns to L, the power is turned on (power switch 5 off), and the signal input from the comparison amplifier circuit 8 is inverted from L to H when the power is on (power switch 5 off). Is detected and the power is turned off.

  The power supply state switching circuit 9 sets the F signal = L and the L signal = L in the power-off state, and sets the F signal = H and the L signal = L in the power-on state (power switch 5 on). When the switch 5 is off), F signal = H and L signal = H are output.

  The first constant voltage circuit 10 generates and outputs DC 20 V using the commercial power supply 1 as an input source, and the first constant voltage control circuit 11 outputs the first constant voltage when the F signal of the power supply state switching circuit 9 is H. DC 20V input from the voltage circuit 10 is output, the second constant voltage circuit 12 receives DC 20V from the first constant voltage control circuit 11, generates and outputs DC 5V, and the second constant voltage control circuit 13 When the L signal of the power supply state switching circuit 9 is H, DC 20 V input from the first constant voltage circuit 10 is output, and the third constant voltage circuit 14 receives DC 20 V from the first constant voltage circuit 10. To generate and output DC5V.

  The output DC 20V of the first constant voltage circuit 10 is supplied as drive power for the power switch conversion circuit 6, the differentiation circuit 7, the comparison amplifier circuit 8, and the power state switching circuit 9, and the third constant voltage circuit 14 It is supplied as a driving power source for the differentiation circuit 7 and the comparison amplification circuit 8.

  The heating off / on key 15a, the up key 15b, and the down key 15c are also arranged on the top plate 4. The heating off / on key 15a switches the heating means 3 between energization and the up key 15b is used to heat the heating means 3. And the down key 15c is operated to decrease the output of the heating means 3.

  The heating switch detection means 16 converts the capacitance that changes when a finger touches the heat off / on key 15a, the up key 15b, and the down key 15c into a voltage change and outputs the voltage change.

  The operating microcomputer 17 detects that a finger has touched the heating off / on key 15a, the up key 15b, and the down key 15c based on a signal input from the heating switch detection unit 16, and whether the heating unit 3 is energized or the heating power is small or large. The setting relating to the output of the heating means 3 is displayed, and information relating to the output of the heating means 3 is transmitted to the control microcomputer 18.

  Further, the operating microcomputer 17 inputs the F signal and the L signal output from the power supply state switching circuit 9 via the first voltage conversion circuit 20 and the second voltage conversion circuit 21, and the power supply OFF state, the power ON state ( The power switch 5 ON) and the power ON state (power switch 5 OFF) are identified, and information on the power supply state indicating whether the contact of the power supply relay 2 should be turned off or on is transmitted to the control microcomputer 18. To do.

  The control microcomputer 18 outputs a signal for turning on the contact of the power relay 2 to the power relay drive circuit 19 based on the information on the power state received from the operation microcomputer 17, and the output of the heating means 3 received from the operation microcomputer 17. On the basis of the information related to this, the presence or absence of energization of the heating means 3 and the magnitude of the heating power are controlled.

The output DC 20V of the first constant voltage control circuit 11 is supplied as a driving power source for the heating switch detection means 16, and the output 5V of the second constant voltage circuit 12 is the operation microcomputer 17, the control microcomputer 18, the first microcomputer. It is supplied as drive power for the voltage conversion circuit 20 and the second voltage conversion circuit 21.

  As shown in FIG. 2, the power switch conversion circuit 6 forms a high-frequency signal of several hundred kHz with a circuit composed of an inverter IC 61, resistors R611 and R612, and a capacitor C611, and supplies the power switch 5 via the transistor Q61. A high frequency voltage of several hundred kHz is applied to convert the capacitance between the power switch 5 and the ground into a DC voltage, and constants of the resistors R621, R622, R624, and R625 are set to the same value, and a predetermined voltage is obtained by a circuit such as an operational amplifier IC62. A voltage reduced by Va is output.

  As shown in FIG. 3, the differentiating circuit 7 superimposes and outputs a change in voltage input from the power switch conversion circuit 6 on a bias voltage obtained by dividing DC5V by resistors R73 and R74.

  As shown in FIG. 4, when the operational amplifier IC81 detects the signal input from the differentiation circuit 7 <(voltage obtained by dividing DC5V by resistors R811 and R812), the comparison amplifier circuit 8 inverts the output from L to H. At the same time, the transistors Q81 and Q82 are turned on, and the + input of the IC81 becomes a voltage obtained by dividing DC5V by the parallel resistance of the resistors R811 and R818 and the resistor R812.

  After that, the comparison amplifier circuit 8 returns the output from H → L when detecting the signal input from the differentiation circuit 7> (DC5V (voltage obtained by dividing the resistance of the resistors R811 and R818) and the resistor R812).

  In the comparison amplifier circuit 8, when the output signal = L and the L signal = H, the transistors Q83 and Q84 are turned on, and the + input of the IC 81 has a DC5V (parallel resistance of resistors R811 and R823) and a resistor. The voltage is divided by R812.

  As shown in FIG. 5, when DC 20V is applied from the first constant voltage circuit 10, the power supply state switching circuit 9 is turned on in the order of transistors Q913 → Q914, and the voltage (DDm−FF) = 20V. At this time, F signal = L and L signal = L are output. When the DC voltage input from the first constant voltage circuit 10 becomes low in a transient situation where the commercial power supply 1 is turned on and off, the transistor Q915 is turned on by the Zener diode ZD91, the comparator IC92, etc. DDm-FF) is greatly reduced to the divided voltage of the resistors R930 and R931.

  When the signal input from the comparison amplifier circuit 8 changes from L → H, the voltage (MSW) = L, and the transistors Q918 → Q919 → Q920 are turned on in this order, the F signal = H, and the diode D94 is turned on. Thus, transistors Q919 and Q920 are kept on.

  After that, when the signal input from the comparison amplifier circuit 8 returns from H → L, the voltage (MSW) changes from L → H, and the transistor Q921 → Q922 is turned on through the resistor R950 and the diode D96. , L signal = H and a voltage obtained by dividing the voltage (L-Lu) (= DC20V) by resistors R913 and R914 is applied to the negative input of the comparator IC91.

After that, when the signal input from the comparison amplifier circuit 8 changes from L to H, the + input of the comparator IC91 becomes a voltage obtained by dividing DC20V by the resistors R915 and R916, and the output of the comparator IC91 becomes L, Transistor Q913 → via diode D92
It turns off in the order of Q914, and the voltage (DDm−FF) = 0V, and the transistor Q916 turns off → Q917 turns on → Q919 turns off → Q920 turns off, and the F signal = L and the L signal = L. .

  About the cooking-by-heating machine comprised as mentioned above, the operation | movement and an effect | action are demonstrated using FIG.

  When the commercial power source 1 is applied to the device, the first constant voltage circuit 10 generates and outputs DC 20V, the third constant voltage circuit 14 generates and outputs DC 5V, the power switch conversion circuit 6, the differentiation circuit 7, The comparison amplifier circuit 8 and the power supply state switching circuit 9 start operation.

  When a person using the device touches the power switch 5 with his / her finger, the output voltage of the power switch conversion circuit 6 decreases and the output voltage of the differentiating circuit 7 becomes DC5V as shown at point A in FIG. After the output is obtained by superimposing the voltage drop on the bias voltage divided by the resistors R73 and R74, it returns to the original voltage with the CR time constant, and the negative input and the positive input of the IC 81 of the comparison amplifier circuit 8 (= DC5V is resistance) R811 and the voltage divided by R812) are larger than ΔV1, the output of IC81 changes from L to H, the F signal of power supply state switching circuit 9 changes from L to H, and the + The input is a voltage obtained by turning on transistors Q81 and Q82 and dividing DC5V (parallel resistance of resistors R811 and R818) by resistor R812, and bias voltage obtained by dividing DC5V by resistors R73 and R74. Higher by also △ V2 than.

  Then, the first constant voltage control circuit 11 receives the F signal = H, is turned on in the order of the transistors Q111 → Q112 and outputs DC 20V, and the second constant voltage circuit 12 outputs DC 5V, and heating The switch detection means 16, the operation microcomputer 17, and the control microcomputer 18 start operation.

  Then, the operating microcomputer 17 detects the F signal = H and the L signal = L through the first voltage conversion circuit 20 and the second voltage conversion circuit 21, and determines that the finger touches the power switch 5. Then, a notification to that effect and sound notification are performed.

  Thereafter, when a person using the device lifts his / her finger from the power switch 5, the output voltage of the power switch conversion circuit 6 rises and the output voltage of the differentiating circuit 7 becomes DC5V, as shown at point B in FIG. After an output in which the voltage increase is superimposed on the bias voltage divided by the resistors R73 and R74, it returns to the original voltage with the CR time constant, and the negative input and positive input of the IC 81 of the comparison amplifier circuit 8 (= DC5V ( The difference between the parallel resistance of the resistors R811 and R818) and the voltage divided by R812) is larger than ΔV2, so that the output of the IC 81 becomes H → L, and the L signal of the power supply state switching circuit 9 becomes L → H. At the same time, the + input of IC81 is a voltage obtained by dividing DC5V (parallel resistance of resistors R811 and R823) and resistor R812 by turning off transistors Q81 and Q82 and turning on Q83 and Q84. Than dividing the bias voltage at the DC5V resistor R73 and R74 is lower by △ V3.

  The second constant voltage control circuit 13 receives the L signal = H, is turned on in the order of the transistors Q131 → Q132, outputs DC 20V, and supplies drive power to the power relay drive circuit 19.

  Further, the operating microcomputer 17 detects the F signal = H and the L signal = H through the first voltage conversion circuit 20 and the second voltage conversion circuit 21 and determines that the finger is separated from the power switch 5. Then, information indicating that the power supply relay 2 should be turned on is transmitted to the control microcomputer 18, and the control microcomputer 18 outputs a signal for turning on the contact of the power supply relay 2 to the power supply relay drive circuit 19.

  The operation microcomputer 17 detects that the heating off / on key 15a, the up key 15b, and the down key 15c are operated based on a signal input from the heating switch detection unit 16, and whether the heating unit 3 outputs or not. And the setting related to the output amount are changed, and this information is transmitted to the control microcomputer 18, and the control microcomputer 18 controls the output of the heating means 3 based on the signal received from the operation microcomputer 17.

  After that, when a person using the device touches the power switch 5 to turn off the main power, the output voltage of the power switch conversion circuit 6 decreases as shown by a point C in FIG. The output voltage of 7 returns to the original voltage with a CR time constant after the output of the voltage drop is superimposed on the bias voltage obtained by dividing DC5V by the resistors R73 and R74. And + input (= DC5V (voltage divided by resistors R811 and R823) and voltage divided by resistor R812) is larger than ΔV3, so that the output of IC81 is changed from L to H, and the power supply state is switched. Both the F signal and L signal of the circuit 9 are changed from H → L, and the + input of the IC 81 is connected to DC5V (resistors R811 and R81) by turning on the transistors Q81 and Q82 and turning off Q83 and Q84. Parallel resistance) and becomes a voltage divided by the resistors R812, than dividing the bias voltage at the DC5V resistor R73 and R74 higher by △ V2 of.

  Then, the first constant voltage control circuit 11 receives the F signal = L and turns off in the order of the transistors Q111 → Q112 to cut off the output of DC 20V, and the second constant voltage circuit 12 cuts off the output of DC 5V. Then, the heating switch detection means 16, the operation microcomputer 17, and the control microcomputer 18 stop operating.

  Further, the second constant voltage control circuit 13 receives the L signal = L, and turns off in the order of the transistors Q131 → Q132 to cut off the output of DC 20V and cut off the supply of the driving power to the power relay driving circuit 19. To do.

  Thereafter, when a person using the device lifts his / her finger from the power switch 5, the output voltage of the power switch conversion circuit 6 rises and the output voltage of the differentiating circuit 7 becomes DC 5V as shown at point D in FIG. 6. After an output in which the voltage increase is superimposed on the bias voltage divided by the resistors R73 and R74, it returns to the original voltage with the CR time constant, and the negative input and positive input of the IC 81 of the comparison amplifier circuit 8 (= DC5V ( Since the difference between the parallel resistance of resistors R811 and R818) and the voltage divided by R812) is greater than ΔV2, the output of IC81 changes from H to L, and the + input of IC81 causes transistors Q81 and Q82 to be off. Thus, DC5V is divided by resistors R811 and R812, which is lower by ΔV1 than the bias voltage obtained by dividing DC5V by resistors R73 and R74.

  With the above configuration, when the power switch 5 is touched when the power is on, the power switch drive circuit 19 is driven by the power switch conversion circuit 6-> differentiation circuit 7-> comparison amplifier circuit 8-> power state switching circuit 9. Even if the operating microcomputer 17 or the control microcomputer 18 runs away due to external noise or the like, the device is used without using any means involving software processing by turning off the power supply and opening the contact of the power relay 2. A person can operate the power switch 5 to reliably cut off the power supply to the heating means 3.

In addition, even when an object is placed on the power switch 5 or when water is spilled when the power is turned off and the finger touches the power switch 5, the object is removed from the power switch 5. The second constant voltage control circuit 13 does not supply DC 20V to the power relay drive circuit 19 because the F signal = H and the L signal = L of the power state switching circuit 9 until the spilling or spilled water is wiped off. And since the control microcomputer 18 does not output a signal for turning on the contact of the power relay 2 to the power relay drive circuit 19, while maintaining the interruption of the energization to the heating means 3 in multiple,
The operating microcomputer 17 prohibits acceptance of an operation for starting energization of the heating means 3 until the object is removed from the power switch 5 or the spilled water is wiped off, thereby improving the safety of the product. it can.

  Further, the reception sensitivity ΔV3 of the power switch 5 in the power-on state is made better than the reception sensitivity ΔV1 of the power switch 5 in the power-off state, and noise when the heating means 3 is energized. It is possible to prevent the reception sensitivity of the power switch 5 from becoming dull, or to prevent a phenomenon in which the power relay 2 can be closed but cannot be opened by operating the power switch 5 in an area where the electric field strength is high, such as in the vicinity of a radio tower. .

  In the first embodiment, when the power supply state switching circuit 9 is in the power supply off state, only the power switch conversion circuit 6, the differentiation circuit 7, the comparison amplification circuit 8, and the power supply state switching circuit 9 are driven. There is also an effect that standby power can be reduced.

  In the first embodiment, when the power supply state switching circuit 9 shifts from the power-on state to the power-off state, both the first constant voltage control circuit 11 and the second constant voltage control circuit 13 output DC 20V. However, the operation microcomputer 17 or the control microcomputer 18 adds a circuit that turns on the transistor Q112 of the first constant voltage control circuit 11, and after the power is turned off, the first operation is performed for a while. The constant voltage control circuit 11 can output DC 20V, and the fan motor can be driven to display that the top plate 4 is in a high temperature state or to cool the inverter circuit 3b.

  Further, a part or all of the heating switch detection means 16, the operation microcomputer 17, and the control microcomputer 18 shown in the first embodiment may be integrated into one microcomputer.

  As described above, the heating cooker according to the present invention opens the contact of the power relay 2 by the operation of the power switch 5 → the power switch conversion circuit 6 → the differentiation circuit 7 → the comparison amplifier circuit 8 → the power state switching circuit 9. In the use environment where the operation microcomputer 17 and the control microcomputer 18 run away due to external noise or the like, the energization to the heating means 3 can be surely cut off, so that the means for induction heating, the radiant heater, the halogen heater In addition, the present invention can be applied to a multi-mouth cooking device using a sheathed heater or the like, or a combination thereof.

DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Power supply relay 3 Heating means 4 Top plate 5 Power switch 6 Power switch conversion circuit 7 Differentiation circuit 8 Comparison amplification circuit 9 Power supply state switching circuit

Claims (4)

An electrostatic device comprising a heating means, a power supply relay for opening / closing a connection between the power supply and the heating means, a driving power supply for opening / closing a contact of the power supply relay, a top plate, and an electrode provided on the top plate. A power switch that is a capacitive touch key, a power switch conversion circuit that converts a capacitance that changes when a finger touches the power switch into a voltage change, and a voltage change that is input from the power switch conversion circuit. A differential circuit that detects and outputs a change amount, a comparison amplifier circuit that outputs an H / L signal based on the magnitude of an input from the differential circuit and a predetermined value, and a power-on state based on an input from the comparison amplifier circuit; By alternately switching the power off state, the power relay and the driving power source are connected when the power is on, and the power relay and the drive are connected when the power is off. A power supply state switching circuit that cuts off the connection of the power supply, wherein the comparison amplification circuit has a polarity when a finger touches the power switch and a change amount is greater than a first predetermined value. The output logic is inverted when the value is larger than the output logic, and the output logic is restored when the signal input from the differentiating circuit has the polarity when the finger is released from the power switch and the change amount is larger than the second predetermined value. Like cooking device. The power supply state switching circuit inverts the input logic from the comparison amplifier circuit when the power supply is off, and then connects the power supply relay and the driving power supply when returning to the original state. The cooking device according to claim 1, wherein when the input logic from the comparison amplifier circuit is inverted, the connection between the power supply relay and the drive power supply is cut off immediately. When the input logic from the comparison amplifier circuit to the power supply state switching circuit is reversed by touching the power switch when the power supply is off, at least an operation for starting energization to the heating means The cooking device according to claim 2, wherein reception of the food is prohibited. 4. The device according to claim 1, wherein the first predetermined value is smaller when the contact of the power relay is closed than when the contact of the power relay is open. 5. Cooking cooker.