Protection device, method and heating kitchen appliance based on heating load on-off control

Abstract

The present invention relates to the technical field of protection circuits, and discloses a protection device, method and heating kitchen appliance based on on-off control of a heating load. The device comprises: a voltage acquisition circuit, a monitoring control circuit and a heating circuit, wherein: the monitoring control circuit is used to determine the operating state of the heating circuit; according to the operating state, a target monitoring voltage threshold matching the operating state is determined, and the voltage value of the target voltage acquired by the monitoring voltage acquisition circuit from the power supply circuit is obtained, so as to perform on-off control on the heating circuit according to the target monitoring voltage threshold and the voltage value, so as to put the heating circuit in the target state. In this way, the voltage value corresponding to the voltage acquisition circuit can be monitored by the monitoring control circuit to perform on-off control on the heating circuit, and there is no need to perform temperature monitoring on the heating load, thereby improving the reliability and accuracy of monitoring the operating state of the heating load, thereby improving the timeliness of on-off control of the heating load, and improving the overall circuit safety performance.

Description

Technical Field

[0001] The present invention relates to the technical field of protection circuits, and in particular to a protection device and method based on on-off control of a heating load, and a heating kitchen appliance. Background Art

[0002] In existing heating kitchen appliances, such as kettles and electric stew pots, a protection circuit for on-off control of the heating load is usually configured. In the current commonly used protection circuit, since the temperature value of the thermistor (i.e., the heating load) of the heating kitchen appliance will increase when the heating kitchen appliance is working, a temperature detection element will be used to monitor the temperature of the thermistor. If the thermistor is in an abnormally high temperature state (such as the heating kitchen appliance is in a dry-burning state without water), the temperature detection element will feedback the disconnection control signal to the single-chip microcomputer, and then the single-chip microcomputer will disconnect the thermistor, so that the heating kitchen appliance stops working. However, this solution requires the temperature detection element to be tightly installed on the heat transfer substrate (such as an aluminum pressing sheet) corresponding to the thermistor and coated with thermal conductive silicone grease. If it is slightly loose, it will be difficult to accurately detect the temperature, and the heating load cannot be timely controlled on and off, which is easy to cause safety hazards. Therefore, there is an urgent need for a circuit protection solution that can improve the accuracy of on-off control of the heating load. Summary of the invention

[0003] The present invention provides a protection device, method and heating kitchen appliance based on on-off control of a heating load, which eliminates the need for temperature monitoring of the heating load, thereby improving the reliability and accuracy of monitoring the operating status of the heating load, thereby improving the timeliness of on-off control of the heating load and enhancing the overall circuit safety performance.

[0004] In order to solve the above technical problems, the first aspect of the present invention discloses a protection device based on on-off control of a heating load, the protection device comprising a voltage acquisition circuit, a monitoring control circuit and a heating circuit, wherein:

[0005] The voltage acquisition terminal of the voltage acquisition circuit is used to electrically connect to the voltage terminal of the power supply circuit, the monitoring terminal of the monitoring control circuit is electrically connected to the voltage terminal of the voltage acquisition circuit, the control terminal of the monitoring control circuit is electrically connected to the controlled terminal of the heating circuit, and the ground terminal of the heating circuit is used to be grounded;

[0006] The monitoring control circuit is used to determine the operating state of the heating circuit; according to the operating state, determine the target monitoring voltage threshold matching the operating state, and monitor the voltage value of the target voltage acquired by the voltage acquisition circuit from the power supply circuit, so as to control the on-off of the heating circuit according to the target monitoring voltage threshold and the voltage value, so that the heating circuit is in a matching target state; the operating state is a working state or a standby state; the standby state is used to indicate that the heating circuit is in a waiting state for response when powered on.

[0007] As an optional implementation, in the first aspect of the present invention, the monitoring control circuit includes a voltage detection subcircuit, a main control subcircuit and an on / off control subcircuit, wherein:

[0008] The monitoring end of the voltage detection subcircuit is electrically connected to the voltage end of the voltage acquisition circuit, the electrical signal sending end of the voltage detection subcircuit is electrically connected to the electrical signal receiving end of the main control subcircuit, the control end of the main control subcircuit is electrically connected to the controlled end of the on-off control subcircuit, the control end of the on-off control subcircuit is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the on-off control subcircuit is electrically connected to the voltage end of the voltage acquisition circuit;

[0009] The main control subcircuit is used to determine a working monitoring voltage threshold matching the working state when the running state is the working state;

[0010] The voltage detection subcircuit is used to monitor the voltage value of the target voltage obtained by the voltage acquisition circuit from the power supply circuit, and transmit the voltage value to the main control subcircuit;

[0011] The main control subcircuit is further used to determine whether the voltage value is greater than the working monitoring voltage threshold; when it is determined that the voltage value is less than or equal to the working monitoring voltage threshold, determine a conduction control signal, and transmit the conduction control signal to the on-off control subcircuit;

[0012] The on-off control subcircuit is used to control the on-off of the heating circuit when receiving the on-off control signal, so that the heating circuit continues to be in the working state;

[0013] The main control subcircuit is further configured to determine a cutoff control signal when it is determined that the voltage value is greater than the working monitoring voltage threshold, and transmit the cutoff control signal to the on-off control subcircuit;

[0014] The on-off control subcircuit is further used to perform disconnection control on the heating circuit when receiving the cut-off control signal, so that the heating circuit is in a power-off state.

[0015] As an optional implementation, in the first aspect of the present invention, the on-off control subcircuit includes a switch control module and a heating on-off control module, wherein:

[0016] The controlled end of the switch control module is electrically connected to the control end of the main control subcircuit, the control end of the switch control module is electrically connected to the controlled end of the heating on-off control module, the grounding end of the switch control module is used for grounding, the control end of the heating on-off control module is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the heating on-off control module is electrically connected to the voltage end of the voltage acquisition circuit;

[0017] The switch control module is used to be in a conduction state when receiving the conduction control signal, and drive the heating on-off control module to conduct; the conduction state is used to indicate that the switch control module conducts electricity;

[0018] The heating on-off control module is used to drive the heating circuit to be turned on when in the on state, so that the heating circuit continues to be in the working state;

[0019] The switch control module is further configured to be in a cut-off state when receiving the cut-off control signal, and control the heating on-off control module to be turned off; the cut-off state is used to indicate that the switch control module is not conducting electricity;

[0020] The heating on-off control module is used to control the heating circuit to be disconnected when in the disconnected state, so that the heating circuit is in a power-off state.

[0021] As an optional implementation, in the first aspect of the present invention, the on-off control subcircuit further includes a first current limiting module, a second current limiting module and a first clamping module, wherein:

[0022] The first end of the first current limiting module is electrically connected to the control end of the main control sub-circuit, the second end of the first current limiting module is electrically connected to the controlled end of the switch control module and the first end of the first clamping module, and the second end of the first clamping module is electrically connected to the ground end of the switch control module;

[0023] The first end of the second current limiting module is electrically connected to the control end of the switch control module, and the second end of the second current limiting module is electrically connected to the controlled end of the heating on-off control module.

[0024] As an optional implementation, in the first aspect of the present invention, the voltage detection subcircuit includes a rectifier module, a third current limiting module, a fourth current limiting module, a second clamping module and a filtering module, wherein:

[0025] The monitoring end of the rectifier module is electrically connected to the voltage end of the voltage acquisition circuit, the electrical signal sending end of the rectifier module is electrically connected to the first end of the third current limiting module, the second end of the third current limiting module is electrically connected to the first end of the second clamping module and the first end of the fourth current limiting module, the second end of the second clamping module is used to electrically connect to the voltage end of the power supply circuit, the second end of the fourth current limiting module is electrically connected to the first end of the filter module and the electrical signal receiving end of the main control sub-circuit, and the second end of the filter module is used for grounding.

[0026] As an optional implementation, in the first aspect of the present invention, the switch control module includes an N-type transistor, wherein:

[0027] The base of the N-type transistor is electrically connected to the second end of the first current limiting module and the first end of the first clamping module, the collector of the N-type transistor is electrically connected to the first end of the second current limiting module, and the emitter of the N-type transistor is electrically connected to the second end of the first clamping module and is grounded;

[0028] The heating on-off control module includes a thyristor device, wherein:

[0029] The cathode of the thyristor device is electrically connected to the controlled end of the heating circuit, the anode of the thyristor device is electrically connected to the voltage end of the voltage acquisition circuit, and the gate of the thyristor device is electrically connected to the second end of the second current limiting module;

[0030] The rectifier module comprises a first diode, wherein:

[0031] The cathode of the first diode is electrically connected to the voltage end of the voltage acquisition circuit, and the anode of the first diode is electrically connected to the first end of the third current limiting module;

[0032] The second clamping module comprises a second diode, wherein:

[0033] The anode of the second diode is electrically connected to the second end of the third current limiting module, and the cathode of the second diode is electrically connected to the voltage end of the power supply circuit.

[0034] The second aspect of the present invention discloses a protection method based on power supply on-off control, which is applied to a protection device based on heating load on-off control, wherein the protection device includes a voltage acquisition circuit, a monitoring control circuit and a heating circuit, wherein:

[0035] The voltage acquisition terminal of the voltage acquisition circuit is used to electrically connect to the voltage terminal of the power supply circuit, the monitoring terminal of the monitoring control circuit is electrically connected to the voltage terminal of the voltage acquisition circuit, the control terminal of the monitoring control circuit is electrically connected to the controlled terminal of the heating circuit, and the ground terminal of the heating circuit is used to be grounded;

[0036] The method comprises:

[0037] The monitoring control circuit determines the operating state of the heating circuit; based on the operating state, determines a target monitoring voltage threshold that matches the operating state, and monitors the voltage value of the target voltage acquired by the voltage acquisition circuit from the power supply circuit, so as to control the on-off of the heating circuit according to the target monitoring voltage threshold and the voltage value, so that the heating circuit is in a matching target state; the operating state is a working state or a standby state; the standby state is used to indicate that the heating circuit is in a waiting state for response when powered on.

[0038] As an optional implementation, in the second aspect of the present invention, the monitoring control circuit includes a voltage detection subcircuit, a main control subcircuit and an on / off control subcircuit, wherein:

[0039] The monitoring end of the voltage detection subcircuit is electrically connected to the voltage end of the voltage acquisition circuit, the electrical signal sending end of the voltage detection subcircuit is electrically connected to the electrical signal receiving end of the main control subcircuit, the control end of the main control subcircuit is electrically connected to the controlled end of the on-off control subcircuit, the control end of the on-off control subcircuit is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the on-off control subcircuit is electrically connected to the voltage end of the voltage acquisition circuit;

[0040] The monitoring control circuit determines a target monitoring voltage threshold matching the operating state according to the operating state, and monitors the voltage value of the target voltage acquired by the voltage acquisition circuit from the power supply circuit, so as to control the on-off of the heating circuit according to the target monitoring voltage threshold and the voltage value, so that the heating circuit is in a matching target state, including:

[0041] When the running state is the working state, the main control subcircuit determines a working monitoring voltage threshold that matches the working state;

[0042] The voltage detection subcircuit monitors the voltage value of the target voltage acquired by the voltage acquisition circuit from the power supply circuit, and transmits the voltage value to the main control subcircuit;

[0043] The main control subcircuit determines whether the voltage value is greater than the working monitoring voltage threshold; when it is determined that the voltage value is less than or equal to the working monitoring voltage threshold, determines a conduction control signal, and transmits the conduction control signal to the on-off control subcircuit; when the on-off control subcircuit receives the conduction control signal, conducts conduction control on the heating circuit so that the heating circuit continues to be in the working state;

[0044] When it is determined that the voltage value is greater than the working monitoring voltage threshold, a cut-off control signal is determined and the cut-off control signal is transmitted to the on-off control subcircuit; when the on-off control subcircuit receives the cut-off control signal, the heating circuit is disconnected to put the heating circuit in a power-off state.

[0045] As an optional implementation, in the second aspect of the present invention, the on-off control subcircuit includes a switch control module and a heating on-off control module, wherein:

[0046] The controlled end of the switch control module is electrically connected to the control end of the main control subcircuit, the control end of the switch control module is electrically connected to the controlled end of the heating on-off control module, the grounding end of the switch control module is used for grounding, the control end of the heating on-off control module is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the heating on-off control module is electrically connected to the voltage end of the voltage acquisition circuit;

[0047] When the on-off control subcircuit receives the on-control signal, the on-control of the heating circuit is performed so that the heating circuit continues to be in the working state, including:

[0048] When the switch control module receives the conduction control signal, it is in the conduction state and drives the heating on-off control module to conduct; the conduction state is used to indicate that the switch control module conducts electricity;

[0049] When the heating on-off control module is in the on state, driving the heating circuit to be turned on so that the heating circuit continues to be in the working state;

[0050] And, when the on-off control subcircuit receives the cut-off control signal, the heating circuit is disconnected to put the heating circuit in a power-off state, including:

[0051] When the switch control module receives the cut-off control signal, it is in the cut-off state and controls the heating on-off control module to be turned off; the cut-off state is used to indicate that the switch control module is not conducting electricity;

[0052] When the heating on-off control module is in the off state, the heating circuit is controlled to be off so that the heating circuit is in the off state.

[0053] A third aspect of the present invention discloses a heating kitchen appliance, the heating kitchen appliance comprising a circuit board, the circuit board comprising a protection device based on heating load on-off control as described in any one of the first aspect of the present invention.

[0054] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0055] In an embodiment of the present invention, the protection device based on on-off control of the heating load includes: a voltage acquisition circuit, a monitoring control circuit and a heating circuit, wherein: the monitoring control circuit is used to determine the operating state of the heating circuit; according to the operating state, a target monitoring voltage threshold matching the operating state is determined, and the voltage value of the target voltage acquired by the monitoring voltage acquisition circuit from the power supply circuit is obtained, so as to control the on-off of the heating circuit according to the target monitoring voltage threshold and the voltage value, so as to put the heating circuit in the target state. In this way, the voltage value corresponding to the voltage acquisition circuit can be monitored by the monitoring control circuit to control the on-off of the heating circuit, and there is no need to monitor the temperature of the heating load, thereby improving the reliability and accuracy of the operating state monitoring of the heating load, thereby improving the timeliness of the on-off control of the heating load and improving the overall circuit safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0057] Figure 1 It is a structural schematic diagram of a protection device based on heating load on-off control disclosed in an embodiment of the present invention;

[0058] Figure 2 It is a structural schematic diagram of another protection device based on heating load on-off control disclosed in an embodiment of the present invention;

[0059] Figure 3 It is a flow chart of a protection method based on heating load on-off control disclosed in an embodiment of the present invention;

[0060] Figure 4 It is a structural schematic diagram of a heating kitchen appliance disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] It should be noted that, unless otherwise clearly specified and limited, the term "electrical connection" in the specification and claims of the present invention and the above-mentioned drawings should be understood in a broad sense. For example, it can be a fixed electrical connection, a detachable electrical connection, or an integral electrical connection; it can be a mechanical electrical connection, an electrical electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements.

[0063] In addition, the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, device, product or end including a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units inherent to these processes, methods, products or ends.

[0064] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0065] The present invention discloses a protection device, method and heating kitchen appliance based on on-off control of a heating load, which eliminates the need for temperature monitoring of the heating load, thereby improving the reliability and accuracy of monitoring the operating status of the heating load, thereby improving the timeliness of on-off control of the heating load and enhancing the overall circuit safety performance.

[0066] Embodiment 1

[0067] See also Figure 1 , Figure 1 The figure is a schematic diagram of a protection device based on heating load on-off control disclosed in an embodiment of the present invention. The protection device can be applied to various types of heating kitchen appliances for heating load on-off control, such as: hot water kettles, electric stew pots, electric cooking pots, etc. Figure 1 As shown, the protection device includes a voltage acquisition circuit 101, a monitoring control circuit 102 and a heating circuit 103, wherein:

[0068] The voltage acquisition terminal of the voltage acquisition circuit 101 is used to electrically connect to the voltage terminal of the power supply circuit 104, the monitoring terminal of the monitoring control circuit 102 is electrically connected to the voltage terminal of the voltage acquisition circuit 101, the control terminal of the monitoring control circuit 102 is electrically connected to the controlled terminal of the heating circuit 103, and the ground terminal of the heating circuit 103 is used to be grounded;

[0069] The monitoring control circuit 102 is used to determine the operating state of the heating circuit 103; according to the operating state, a target monitoring voltage threshold matching the operating state is determined, and the voltage value of the target voltage acquired by the monitoring voltage acquisition circuit 101 from the power supply circuit 104 is controlled to on and off the heating circuit 103 according to the target monitoring voltage threshold and the voltage value, so that the heating circuit 103 is in a matching target state.

[0070] In the embodiment of the present invention, the operating state is a working state or a standby state (the standby state indicates that the heating circuit is in a state of waiting for response when powered). For example, since the heating kitchen appliance will generate heat transfer interaction with the water or food in the container when it is working (such as a kettle boiling water, or a cooking machine cooking), the heat of the heating load is continuously absorbed by the water or food in the container, so that the heating load is in a stable high temperature state with little fluctuation, and is also in a stable high impedance state with little fluctuation. Then, by monitoring the change of the voltage value corresponding to the voltage acquisition circuit 101, and according to the target detection voltage threshold matched with the operating state determined in real time, it can be determined whether the heating load (i.e., the heating circuit 103) has a high temperature abnormality. If not, it continues to be in the working / standby state. If so, the power supply between the heating load and the power circuit is immediately disconnected to stop the heating load from working.

[0071] It can be seen that the embodiment of the present invention can monitor the voltage value corresponding to the voltage acquisition circuit through the monitoring control circuit to control the on-off of the heating circuit, without the need to monitor the temperature of the heating load, thereby improving the reliability and accuracy of monitoring the operating status of the heating load, thereby improving the timeliness of the on-off control of the heating load and enhancing the overall circuit safety performance.

[0072] In an optional embodiment, if Figure 2 As shown, Figure 2 This is a schematic diagram of the structure of another protection device based on heating load on-off control disclosed in an embodiment of the present invention, wherein the monitoring control circuit 102 includes a voltage detection subcircuit, a main control subcircuit and an on-off control subcircuit, wherein:

[0073] The monitoring end of the voltage detection subcircuit is electrically connected to the voltage end of the voltage acquisition circuit 101, the electrical signal sending end of the voltage detection subcircuit is electrically connected to the electrical signal receiving end of the main control subcircuit, the control end of the main control subcircuit is electrically connected to the controlled end of the on-off control subcircuit, the control end of the on-off control subcircuit is electrically connected to the controlled end of the heating circuit 103, and the voltage receiving end of the on-off control subcircuit is electrically connected to the voltage end of the voltage acquisition circuit 101;

[0074] The main control subcircuit is used to determine a working monitoring voltage threshold that matches the working state when the operating state is the working state;

[0075] A voltage detection subcircuit, used to monitor the voltage value of the target voltage obtained by the voltage acquisition circuit 101 from the power supply circuit 104, and transmit the voltage value to the main control subcircuit;

[0076] The main control subcircuit is also used to determine whether the voltage value is greater than the working monitoring voltage threshold; when it is determined that the voltage value is less than or equal to the working monitoring voltage threshold, a conduction control signal is determined and the conduction control signal is transmitted to the on-off control subcircuit;

[0077] The on-off control subcircuit is used to control the heating circuit 103 to be on when receiving the on-control signal, so that the heating circuit 103 continues to be in the working state;

[0078] The main control subcircuit is further used to determine a cutoff control signal when it is determined that the voltage value is greater than the working monitoring voltage threshold, and transmit the cutoff control signal to the on-off control subcircuit;

[0079] The on-off control subcircuit is further used to perform disconnection control on the heating circuit 103 when receiving a cut-off control signal, so that the heating circuit 103 is in a power-off state.

[0080] In this optional embodiment, further, the main control subcircuit is also used to determine a standby monitoring voltage threshold matching the standby state when the operating state is the standby state;

[0081] The voltage detection sub-circuit is also used to monitor the voltage value of the target voltage obtained by the voltage acquisition circuit 101 from the power supply circuit 104, and transmit the voltage value to the main control sub-circuit;

[0082] The main control subcircuit is also used to determine whether the voltage value is greater than the standby monitoring voltage threshold; when it is determined that the voltage value is less than or equal to the standby monitoring voltage threshold, a cutoff control signal is determined and the cutoff control signal is transmitted to the on-off control subcircuit;

[0083] The on-off control subcircuit is further used to control the heating circuit 103 to be turned off when receiving a cut-off control signal, so that the heating circuit 103 continues to be in a standby state.

[0084] For example, if Figure 1 As shown, when the kettle is boiling water normally, its heating load is in a stable high-impedance state with little fluctuation, then the voltage detection subcircuit will monitor that the voltage value of the target voltage obtained by the voltage acquisition circuit 101 is 2~3V, and feed it back to the main control subcircuit, and then the main control subcircuit determines the working monitoring voltage threshold value according to the working state of the heating load, such as 3.2V, and can determine that the voltage value is less than the working monitoring voltage threshold value, and then send a conduction control signal to the on-off subcircuit, so that the on-off subcircuit controls the conduction of the heating load, so that the heating load of the kettle continues to be in a working state.

[0085] When the kettle is dry-boiling without water, since it cannot generate heat transfer with the water in the container, its heating load will be in a fluctuating high-impedance state. The voltage detection subcircuit will monitor that the voltage value of the target voltage obtained by the voltage acquisition circuit 101 is between 3.5 and 4.5 V, and feed it back to the main control subcircuit. Then the main control subcircuit determines the working monitoring voltage threshold value according to the working state of the heating load, such as 3.2 V, and can determine that the voltage value is greater than the working monitoring voltage threshold value. Then, a cutoff control signal is sent to the on-off subcircuit, and then the on-off subcircuit disconnects the heating load, so that the heating load of the kettle is in a power-off state, thereby the heating load stops working to achieve a protective effect.

[0086] When the heating load of the kettle is in a standby state (such as the power supply circuit supplies power to the heating load in a low-power mode so that the heating load can respond to subsequent work instructions at any time), the voltage detection subcircuit will monitor that the voltage value of the target voltage acquired by the voltage acquisition circuit 101 is 5V, and feed it back to the main control subcircuit. Then the main control subcircuit determines the standby monitoring voltage threshold value, such as 5V, according to the standby state of the heating load. It can be determined that the voltage value is equal to the standby monitoring voltage threshold value, and then sends a cut-off control signal to the on-off subcircuit, so that the on-off subcircuit disconnects the heating load, so that the heating load of the kettle continues to be in a standby state.

[0087] It can be seen that this optional embodiment can monitor the voltage value corresponding to the voltage acquisition circuit through the voltage detection sub-circuit, and compare the voltage value and the determined target monitoring voltage threshold matching the operating state through the main control sub-circuit, and then determine whether the heating circuit is in an abnormally high temperature state, thereby achieving flexible on-off control of the heating circuit. In this way, the reliability and accuracy of the on-off control of the heating circuit can be improved, and then the timeliness of the on-off control of the heating circuit can be improved, thereby reducing the occurrence of dry burning of the equipment and improving the protection effect of the heating kitchen appliances; at the same time, there is no need to use a thermostat, which can effectively reduce the heat transfer packaging materials required for assembly and save costs.

[0088] In another optional embodiment, the on-off control subcircuit includes a switch control module and a heating on-off control module, wherein:

[0089] The controlled end of the switch control module is electrically connected to the control end of the main control sub-circuit, the control end of the switch control module is electrically connected to the controlled end of the heating on-off control module, the grounding end of the switch control module is used for grounding, the control end of the heating on-off control module is electrically connected to the controlled end of the heating circuit 103, and the voltage receiving end of the heating on-off control module is electrically connected to the voltage end of the voltage acquisition circuit 101;

[0090] The switch control module is used to be in a conduction state when receiving a conduction control signal, and drive the heating on-off control module to conduct; the conduction state is used to indicate that the switch control module conducts electricity;

[0091] A heating on-off control module, used to drive the heating circuit 103 to be turned on when in the on state, so that the heating circuit 103 continues to be in the working state;

[0092] The switch control module is also used to be in a cut-off state when receiving a cut-off control signal, and control the heating on-off control module to be turned off; the cut-off state is used to indicate that the switch control module is not conducting electricity;

[0093] The heating on-off control module is used to control the heating circuit 103 to be disconnected when in the disconnected state, so that the heating circuit 103 is in the power-off state.

[0094] In this optional embodiment, further, the on-off control subcircuit also includes a first current limiting module R5, a second current limiting module R3 / R4 and a first clamping module R6, wherein:

[0095] A first end of the first current limiting module R5 is electrically connected to the control end of the main control subcircuit, a second end of the first current limiting module R5 is electrically connected to the controlled end of the switch control module and the first end of the first clamping module R6, and a second end of the first clamping module R6 is electrically connected to the ground end of the switch control module;

[0096] A first end of the second current limiting module R3 / R4 is electrically connected to a control end of the switch control module, and a second end of the second current limiting module R3 / R4 is electrically connected to a controlled end of the heating on-off control module.

[0097] Optionally, the first current limiting module R5, the second current limiting module R3 / R4 and the first clamping module R6 may each include a corresponding single resistor, or include a plurality of resistors connected in series, or include a plurality of resistors connected in parallel (eg, Figure 2 as shown).

[0098] In this optional embodiment, if Figure 2As shown, further, the switch control module includes an N-type transistor Q1, wherein:

[0099] The base of the N-type transistor Q1 is electrically connected to the second end of the first current limiting module R5 and the first end of the first clamping module R6, the collector of the N-type transistor Q1 is electrically connected to the first end of the second current limiting module R3 / R4, and the emitter of the N-type transistor Q1 is electrically connected to the second end of the first clamping module R6 and is grounded.

[0100] And, the heating on-off control module includes a thyristor device T1, wherein:

[0101] The cathode of the thyristor device T1 is electrically connected to the controlled end of the heating circuit 103 , the anode of the thyristor device T1 is electrically connected to the voltage end of the voltage acquisition circuit 101 , and the gate of the thyristor device T1 is electrically connected to the second end of the second current limiting module R3 / R4 .

[0102] For example, if Figure 2 As shown, when the heating load RL of the kettle is in a dry-boiling state without water, its temperature will gradually increase, that is, the resistance value of RL is dynamically increasing, so the current flowing through the voltage acquisition circuit 101 will dynamically decrease, the voltage detection subcircuit detects the corresponding value and feeds back to the main control subcircuit, and the main control subcircuit gives an instruction to control the on-off control subcircuit to be disconnected, that is, the N-type transistor Q1 is in a cut-off state, the thyristor device T1 is not turned on and does not work, and the load RL is disconnected, thereby stopping heating; and when the heating load RL of the kettle is in a normal water-boiling state, its temperature will be relatively stable, that is, the resistance value of RL is stable and does not fluctuate much, so the current flowing through the voltage acquisition circuit 101 also fluctuates little, the voltage detection subcircuit detects the corresponding value and feeds back to the main control subcircuit, and the main control subcircuit gives an instruction to control the on-off control subcircuit to be turned on, that is, the N-type transistor Q1 is in a conducting state, the thyristor device T1 and the load RL are also in a conducting state, so that the load RL continues to be in a working state.

[0103] Optionally, the switch control module may include other components or assemblies capable of realizing the above-mentioned on-off control function in addition to the N-type transistor Q1; similarly, the heating on-off control module may include other components or assemblies capable of realizing the above-mentioned on-off control function in addition to the thyristor.

[0104] In this optional embodiment, if Figure 2 As shown, further, the voltage acquisition circuit 101 may include a corresponding single resistor, or include multiple resistors connected in series, or include multiple resistors connected in parallel (such as Figure 2 RX1 / RX2 in); and the heating circuit 103 may include a corresponding single thermistor (such as Figure 2RL in the figure), or includes multiple thermistors connected in series, or includes multiple thermistors connected in parallel; and the main control subcircuit may include components or assemblies that can realize the above-mentioned voltage value comparison and on-off control functions.

[0105] It can be seen that this optional embodiment can flexibly construct the on-off control subcircuit, so as to realize the on-off control process of the heating circuit. In this way, the reliability, accuracy and efficiency of the on-off control of the heating circuit are improved, and then the timeliness of the on-off control of the heating circuit is improved, so that the heating kitchen appliances can be effectively protected and the safety performance of the equipment can be improved.

[0106] In yet another optional embodiment, the voltage detection subcircuit includes a rectifier module, a third current limiting module R2, a fourth current limiting module R1, a second clamping module and a filtering module C1, wherein:

[0107] The monitoring end of the rectifier module is electrically connected to the voltage end of the voltage acquisition circuit 101, the electrical signal sending end of the rectifier module is electrically connected to the first end of the third current limiting module R2, the second end of the third current limiting module R2 is electrically connected to the first end of the second clamping module and the first end of the fourth current limiting module R1, the second end of the second clamping module is used to electrically connect to the voltage end of the power supply circuit 104, the second end of the fourth current limiting module R1 is electrically connected to the first end of the filter module C1 and the electrical signal receiving end of the main control subcircuit, and the second end of the filter module C1 is used for grounding.

[0108] In this optional embodiment, further, the rectifier module includes a first diode D1, wherein:

[0109] The cathode of the first diode D1 is electrically connected to the voltage end of the voltage acquisition circuit 101 , and the anode of the first diode D1 is electrically connected to the first end of the third current limiting module R2 .

[0110] And, the second clamping module includes a second diode D2, wherein:

[0111] An anode of the second diode D2 is electrically connected to the second end of the third current limiting module R2 , and a cathode of the second diode D2 is electrically connected to the voltage end of the power supply circuit 104 .

[0112] Optionally, the third current limiting module R2 and the fourth current limiting module R1 may include a corresponding single resistor, or include multiple resistors connected in series, or include multiple resistors connected in parallel; and the filtering module C1 may include components or assemblies capable of realizing a filtering function.

[0113] It can be seen that this optional embodiment can flexibly construct the voltage detection sub-circuit, so as to realize the monitoring process of the voltage value corresponding to the voltage acquisition circuit. In this way, the monitoring reliability and accuracy of the voltage value corresponding to the voltage acquisition circuit are improved, and then the reliability and accuracy of the subsequent main control sub-circuit for abnormal judgment of the voltage value are improved, thereby improving the on-off control accuracy of the on-off control sub-circuit and reducing the occurrence of dry burning of equipment.

[0114] Embodiment 2

[0115] See also Figure 3 , Figure 3 1 is a flow chart of a protection method based on power on-off control disclosed in an embodiment of the present invention, wherein the method is applied to a protection device based on heating load on-off control, the protection device comprising a voltage acquisition circuit, a monitoring control circuit and a heating circuit, wherein:

[0116] The voltage acquisition end of the voltage acquisition circuit is used to electrically connect to the voltage end of the power supply circuit, the monitoring end of the monitoring control circuit is electrically connected to the voltage end of the voltage acquisition circuit, the control end of the monitoring control circuit is electrically connected to the controlled end of the heating circuit, and the grounding end of the heating circuit is used for grounding; Figure 3 As shown, the method may include the following steps:

[0117] 301. The monitoring control circuit determines the operating state of the heating circuit;

[0118] 302. According to the operating state, determine the target monitoring voltage threshold that matches the operating state, and monitor the voltage value of the target voltage acquired by the voltage acquisition circuit from the power supply circuit, so as to control the on-off of the heating circuit according to the target monitoring voltage threshold and the voltage value, so that the heating circuit is in a matching target state.

[0119] In the embodiment of the present invention, the operating state is a working state or a standby state; the standby state is used to indicate that the heating circuit is in a state of waiting for a response when powered.

[0120] It can be seen that the implementation of the embodiment of the present invention can monitor the voltage value corresponding to the voltage acquisition circuit through the monitoring control circuit to control the on-off of the heating circuit, without the need to monitor the temperature of the heating load, thereby improving the reliability and accuracy of monitoring the operating status of the heating load, thereby improving the timeliness of the on-off control of the heating load and enhancing the overall circuit safety performance.

[0121] In an optional embodiment, the monitoring control circuit includes a voltage detection subcircuit, a main control subcircuit and an on / off control subcircuit, wherein:

[0122] The monitoring end of the voltage detection subcircuit is electrically connected to the voltage end of the voltage acquisition circuit, the electrical signal sending end of the voltage detection subcircuit is electrically connected to the electrical signal receiving end of the main control subcircuit, the control end of the main control subcircuit is electrically connected to the controlled end of the on-off control subcircuit, the control end of the on-off control subcircuit is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the on-off control subcircuit is electrically connected to the voltage end of the voltage acquisition circuit.

[0123] The monitoring control circuit determines a target monitoring voltage threshold value matching the operating state according to the operating state, and the voltage value of the target voltage obtained by the monitoring voltage acquisition circuit from the power supply circuit, so as to control the on-off of the heating circuit according to the target monitoring voltage threshold value and the voltage value, so that the heating circuit is in a matching target state, including:

[0124] When the operation state is the working state, the main control subcircuit determines a working monitoring voltage threshold that matches the working state;

[0125] The voltage detection subcircuit monitors the voltage value of the target voltage obtained by the voltage acquisition circuit from the power supply circuit, and transmits the voltage value to the main control subcircuit;

[0126] The main control subcircuit determines whether the voltage value is greater than the working monitoring voltage threshold; when it is determined that the voltage value is less than or equal to the working monitoring voltage threshold, a conduction control signal is determined, and the conduction control signal is transmitted to the on-off control subcircuit; when the on-off control subcircuit receives the conduction control signal, the heating circuit is controlled to be on, so that the heating circuit continues to be in a working state;

[0127] When it is determined that the voltage value is greater than the working monitoring voltage threshold, a cut-off control signal is determined and transmitted to the on-off control subcircuit; when the on-off control subcircuit receives the cut-off control signal, the heating circuit is disconnected to put the heating circuit in a power-off state.

[0128] It can be seen that this optional embodiment can monitor the voltage value corresponding to the voltage acquisition circuit through the voltage detection sub-circuit, and compare the voltage value and the determined target monitoring voltage threshold matching the operating state through the main control sub-circuit, and then determine whether the heating circuit is in an abnormally high temperature state, thereby achieving flexible on-off control of the heating circuit. In this way, the reliability and accuracy of the on-off control of the heating circuit can be improved, and then the timeliness of the on-off control of the heating circuit can be improved, thereby reducing the occurrence of dry burning of the equipment and improving the protection effect of the heating kitchen appliances; at the same time, there is no need to use a thermostat, which can effectively reduce the heat transfer packaging materials required for assembly and save costs.

[0129] In another optional embodiment, the on-off control subcircuit includes a switch control module and a heating on-off control module, wherein:

[0130] The controlled end of the switch control module is electrically connected to the control end of the main control subcircuit, the control end of the switch control module is electrically connected to the controlled end of the heating on-off control module, the grounding end of the switch control module is used for grounding, the control end of the heating on-off control module is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the heating on-off control module is electrically connected to the voltage end of the voltage acquisition circuit.

[0131] When the on-off control subcircuit receives the on-control signal, the heating circuit is controlled to be on, so that the heating circuit continues to be in a working state, including:

[0132] When the switch control module receives the conduction control signal, it is in the conduction state and drives the heating on-off control module to conduct; the conduction state is used to indicate that the switch control module conducts electricity;

[0133] When the heating on-off control module is in the on state, the heating circuit is driven to be turned on so that the heating circuit continues to be in the working state;

[0134] And, when the on-off control subcircuit receives the cut-off control signal, the heating circuit is disconnected to put the heating circuit in a power-off state, including:

[0135] When the switch control module receives the cut-off control signal, it is in the cut-off state and controls the heating on-off control module to be turned off; the cut-off state is used to indicate that the switch control module is not conducting;

[0136] When the heating on-off control module is in the off state, the heating circuit is controlled to be off so that the heating circuit is in the off state.

[0137] It can be seen that this optional embodiment can realize the on-off control process of the heating circuit by flexibly constructing the on-off control subcircuit, thereby improving the reliability, accuracy and efficiency of the on-off control of the heating circuit, and further improving the timeliness of the on-off control of the heating circuit, thereby effectively protecting the heating kitchen appliances and improving the safety performance of the equipment.

[0138] Embodiment 3

[0139] See also Figure 4 , Figure 4 1 is a schematic diagram of a heating kitchen appliance disclosed in an embodiment of the present invention, the heating kitchen appliance includes a circuit board, the circuit board includes any protection device based on heating load on-off control as in the first embodiment, and the heating kitchen appliance includes but is not limited to a kettle, an electric stew pot, an electric cooking pot, etc. It should be noted that for a detailed description of the protection device based on heating load on-off control, please refer to the specific description of the relevant content in the first embodiment, which will not be repeated in this embodiment.

[0140] It can be seen that implementation Figure 4The described heating kitchen appliance can obtain the voltage value corresponding to the circuit by monitoring the control circuit to control the on and off of the heating circuit, without the need to monitor the temperature of the heating load, thereby improving the reliability and accuracy of monitoring the operating status of the heating load, thereby improving the timeliness of the on and off control of the heating load and improving the overall equipment safety performance.

[0141] The above is a detailed introduction to a protection device, method and heating kitchen appliance based on on-off control of a heating load disclosed in an embodiment of the present invention. Specific embodiments are used in this article to illustrate the principle and implementation mode of the present invention, but the above preferred embodiments are not used to limit the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for a general technician in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and the scope of application without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is defined by the claims.

Claims

1. A protection device based on heating load on-off control, characterized in that: The protection device comprises a voltage acquisition circuit, a monitoring control circuit and a heating circuit, wherein: The voltage acquisition terminal of the voltage acquisition circuit is used to electrically connect to the voltage terminal of the power supply circuit, the monitoring terminal of the monitoring control circuit is electrically connected to the voltage terminal of the voltage acquisition circuit, the control terminal of the monitoring control circuit is electrically connected to the controlled terminal of the heating circuit, and the ground terminal of the heating circuit is used to be grounded; The monitoring control circuit is used to determine the operating state of the heating circuit; according to the operating state, determine a target monitoring voltage threshold matching the operating state, and monitor the voltage value of the target voltage acquired by the voltage acquisition circuit from the power supply circuit, so as to control the on-off of the heating circuit according to the target monitoring voltage threshold and the voltage value, so that the heating circuit is in a matching target state; the operating state is a working state or a standby state; the standby state is used to indicate that the heating circuit is in a waiting state for response when powered on; And, the monitoring control circuit includes a voltage detection subcircuit, a main control subcircuit and an on-off control subcircuit, wherein: The monitoring end of the voltage detection subcircuit is electrically connected to the voltage end of the voltage acquisition circuit, the electrical signal sending end of the voltage detection subcircuit is electrically connected to the electrical signal receiving end of the main control subcircuit, the control end of the main control subcircuit is electrically connected to the controlled end of the on-off control subcircuit, the control end of the on-off control subcircuit is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the on-off control subcircuit is electrically connected to the voltage end of the voltage acquisition circuit; The main control subcircuit is used to determine a working monitoring voltage threshold matching the working state when the running state is the working state; The voltage detection subcircuit is used to monitor the voltage value of the target voltage obtained by the voltage acquisition circuit from the power supply circuit, and transmit the voltage value to the main control subcircuit; The main control subcircuit is further used to determine whether the voltage value is greater than the working monitoring voltage threshold; when it is determined that the voltage value is less than or equal to the working monitoring voltage threshold, determine a conduction control signal, and transmit the conduction control signal to the on-off control subcircuit; The on-off control subcircuit is used to control the on-off of the heating circuit when receiving the on-off control signal, so that the heating circuit continues to be in the working state; The main control subcircuit is further configured to determine a cutoff control signal when it is determined that the voltage value is greater than the working monitoring voltage threshold, and transmit the cutoff control signal to the on-off control subcircuit; The on-off control subcircuit is further used to perform disconnection control on the heating circuit when receiving the cut-off control signal, so that the heating circuit is in a power-off state.

2. The protection device based on heating load on-off control according to claim 1 is characterized in that: The on-off control subcircuit includes a switch control module and a heating on-off control module, wherein: The controlled end of the switch control module is electrically connected to the control end of the main control subcircuit, the control end of the switch control module is electrically connected to the controlled end of the heating on-off control module, the grounding end of the switch control module is used for grounding, the control end of the heating on-off control module is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the heating on-off control module is electrically connected to the voltage end of the voltage acquisition circuit; The switch control module is used to be in a conduction state when receiving the conduction control signal, and drive the heating on-off control module to conduct; the conduction state is used to indicate that the switch control module conducts electricity; The heating on-off control module is used to drive the heating circuit to be turned on when in the on state, so that the heating circuit continues to be in the working state; The switch control module is further configured to be in a cut-off state when receiving the cut-off control signal, and control the heating on-off control module to be turned off; the cut-off state is used to indicate that the switch control module is not conducting electricity; The heating on-off control module is used to control the heating circuit to be disconnected when in the disconnected state, so that the heating circuit is in a power-off state.

3. The protection device based on heating load on-off control according to claim 2 is characterized in that: The on-off control subcircuit further includes a first current limiting module, a second current limiting module and a first clamping module, wherein: The first end of the first current limiting module is electrically connected to the control end of the main control sub-circuit, the second end of the first current limiting module is electrically connected to the controlled end of the switch control module and the first end of the first clamping module, and the second end of the first clamping module is electrically connected to the ground end of the switch control module; The first end of the second current limiting module is electrically connected to the control end of the switch control module, and the second end of the second current limiting module is electrically connected to the controlled end of the heating on-off control module.

4. The protection device based on heating load on-off control according to claim 3 is characterized in that: The voltage detection subcircuit includes a rectifier module, a third current limiting module, a fourth current limiting module, a second clamping module and a filtering module, wherein: The monitoring end of the rectifier module is electrically connected to the voltage end of the voltage acquisition circuit, the electrical signal sending end of the rectifier module is electrically connected to the first end of the third current limiting module, the second end of the third current limiting module is electrically connected to the first end of the second clamping module and the first end of the fourth current limiting module, the second end of the second clamping module is used to electrically connect to the voltage end of the power supply circuit, the second end of the fourth current limiting module is electrically connected to the first end of the filter module and the electrical signal receiving end of the main control sub-circuit, and the second end of the filter module is used for grounding.

5. The protection device based on heating load on-off control according to claim 4 is characterized in that: The switch control module includes an N-type transistor, wherein: The base of the N-type transistor is electrically connected to the second end of the first current limiting module and the first end of the first clamping module, the collector of the N-type transistor is electrically connected to the first end of the second current limiting module, and the emitter of the N-type transistor is electrically connected to the second end of the first clamping module and is grounded; The heating on-off control module includes a thyristor device, wherein: The cathode of the thyristor device is electrically connected to the controlled end of the heating circuit, the anode of the thyristor device is electrically connected to the voltage end of the voltage acquisition circuit, and the gate of the thyristor device is electrically connected to the second end of the second current limiting module; The rectifier module comprises a first diode, wherein: The cathode of the first diode is electrically connected to the voltage end of the voltage acquisition circuit, and the anode of the first diode is electrically connected to the first end of the third current limiting module; The second clamping module comprises a second diode, wherein: The anode of the second diode is electrically connected to the second end of the third current limiting module, and the cathode of the second diode is electrically connected to the voltage end of the power supply circuit.

6. A protection method based on power on / off control, characterized in that: The method is applied to a protection device based on heating load on-off control, the protection device comprising a voltage acquisition circuit, a monitoring control circuit and a heating circuit, wherein: The voltage acquisition terminal of the voltage acquisition circuit is used to electrically connect to the voltage terminal of the power supply circuit, the monitoring terminal of the monitoring control circuit is electrically connected to the voltage terminal of the voltage acquisition circuit, the control terminal of the monitoring control circuit is electrically connected to the controlled terminal of the heating circuit, and the ground terminal of the heating circuit is used to be grounded; The method comprises: The monitoring control circuit determines the operating state of the heating circuit; according to the operating state, determines a target monitoring voltage threshold matching the operating state, and monitors the voltage value of the target voltage acquired by the voltage acquisition circuit from the power supply circuit, so as to control the on-off of the heating circuit according to the target monitoring voltage threshold and the voltage value, so as to make the heating circuit in a matching target state; the operating state is a working state or a standby state; the standby state is used to indicate that the heating circuit is in a waiting state for response when powered on; And, the monitoring control circuit includes a voltage detection subcircuit, a main control subcircuit and an on-off control subcircuit, wherein: The monitoring end of the voltage detection subcircuit is electrically connected to the voltage end of the voltage acquisition circuit, the electrical signal sending end of the voltage detection subcircuit is electrically connected to the electrical signal receiving end of the main control subcircuit, the control end of the main control subcircuit is electrically connected to the controlled end of the on-off control subcircuit, the control end of the on-off control subcircuit is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the on-off control subcircuit is electrically connected to the voltage end of the voltage acquisition circuit; The step of placing the heating circuit in a matching target state comprises: When the running state is the working state, the main control subcircuit determines a working monitoring voltage threshold that matches the working state; The voltage detection subcircuit monitors the voltage value of the target voltage acquired by the voltage acquisition circuit from the power supply circuit, and transmits the voltage value to the main control subcircuit; The main control subcircuit determines whether the voltage value is greater than the working monitoring voltage threshold; when it is determined that the voltage value is less than or equal to the working monitoring voltage threshold, determines a conduction control signal, and transmits the conduction control signal to the on-off control subcircuit; when the on-off control subcircuit receives the conduction control signal, conducts conduction control on the heating circuit so that the heating circuit continues to be in the working state; When it is determined that the voltage value is greater than the working monitoring voltage threshold, a cut-off control signal is determined and the cut-off control signal is transmitted to the on-off control subcircuit; when the on-off control subcircuit receives the cut-off control signal, the heating circuit is disconnected to put the heating circuit in a power-off state.

7. The protection method based on power on / off control according to claim 6, characterized in that: The on-off control subcircuit includes a switch control module and a heating on-off control module, wherein: The controlled end of the switch control module is electrically connected to the control end of the main control subcircuit, the control end of the switch control module is electrically connected to the controlled end of the heating on-off control module, the grounding end of the switch control module is used for grounding, the control end of the heating on-off control module is electrically connected to the controlled end of the heating circuit, and the voltage receiving end of the heating on-off control module is electrically connected to the voltage end of the voltage acquisition circuit; When the on-off control subcircuit receives the on-control signal, the on-control of the heating circuit is performed so that the heating circuit continues to be in the working state, including: When the switch control module receives the conduction control signal, it is in the conduction state and drives the heating on-off control module to conduct; the conduction state is used to indicate that the switch control module conducts electricity; When the heating on-off control module is in the on state, driving the heating circuit to be turned on so that the heating circuit continues to be in the working state; And, when the on-off control subcircuit receives the cut-off control signal, the heating circuit is disconnected to put the heating circuit in a power-off state, including: When the switch control module receives the cut-off control signal, it is in the cut-off state and controls the heating on-off control module to be turned off; the cut-off state is used to indicate that the switch control module is not conducting electricity; When the heating on-off control module is in the off state, the heating circuit is controlled to be off so that the heating circuit is in the off state.

8. A heating kitchen appliance, comprising a circuit board, characterized in that: The circuit board includes a protection device based on on-off control of a heating load as described in any one of claims 1 to 5.

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