Heating control circuit and electric kettle

Abstract

The utility model discloses a heating control circuit and an electric kettle. The heating control circuit can be applied to the electric kettle. The heating control circuit comprises a control chip, a relay, a silicon controlled rectifier and a zero cross detection circuit; a control chip is used for heating a heating wire controlled by a silicon controlled rectifier and a relay which are connected in parallel, when the power of a heating control circuit meets a first preset condition, the control chip controls the silicon controlled rectifier to be switched on according to a zero crossing point of a zero crossing detection circuit, and controls the relay to be switched off after the silicon controlled rectifier is switched on, so that frequent on-load start and stop of the relay are reduced; and when the power of the heating control circuit meets a second preset condition, the control chip controls the relay to be closed, and after the relay is closed, the silicon controlled rectifier is controlled to be cut off according to the zero crossing point of the zero crossing detection circuit, so that rapid heating is realized. According to the technical scheme, the problem of electric arc ablation of the relay caused by on-load start and stop of the relay can be solved, and the service life of the relay can be further prolonged.

Description

Technical Field

[0001] This application relates to the technical field of heating control, and particularly to a heating control circuit and an electric kettle. Background Art

[0002] With the increasing improvement of people's living standards, the requirements for high-quality life for household appliances such as electric kettles are also getting higher and higher. Electric kettles are also developing in the direction of multi-function and intelligence. Many electric kettle products on the market have the function of automatic constant temperature. This function keeps the temperature in the kettle constant, allowing users to drink warm water at any time and bringing a good experience to users.

[0003] Currently, the automatic constant temperature function of existing electric kettles generally controls the heating wire through a relay for automatic constant temperature. However, since achieving automatic constant temperature will cause the relay to repeatedly start and stop under load, this will cause the contacts of the relay to be easily arced and eroded, which will in turn affect the service life of the relay contacts. Summary of the Utility Model

[0004] The purpose of this application is to provide a heating control circuit and an electric kettle to solve the problem in related technologies that the relay repeatedly switches between the closed and open states, which will in turn affect the service life of the relay.

[0005] To achieve the above purpose, this application provides the following technical solutions:

[0006] In the first aspect, this application provides a heating control circuit, including: a control chip, a relay, a thyristor, and a zero-crossing detection circuit; there are multiple I / O ports on the control chip, the relay and the thyristor are connected in parallel, the relay and the thyristor are electrically connected to different I / O ports of the control chip, and the control chip is used to control the working states of the relay and the thyristor; the input end of the zero-crossing detection circuit is electrically connected to an external AC power supply, and the output end of the zero-crossing detection circuit is electrically connected to an I / O port of the control chip; the zero-crossing detection circuit is used to provide a switching signal for the control chip to switch the working states of the relay and the thyristor; when the power of the heating control circuit meets the first preset condition, the control chip controls the thyristor to conduct and controls the relay to disconnect; when the power of the heating control circuit meets the second preset condition, the control chip controls the relay to close and controls the thyristor to cut off.

[0007] Preferably, the heating control circuit further includes: a thyristor drive circuit and a relay drive circuit; an input end of the thyristor drive circuit is electrically connected to an I / O port of the control chip, an output end of the thyristor drive circuit is electrically connected to the thyristor, and the thyristor drive circuit is configured to receive a first control instruction from the control chip and control conduction and cut-off of the thyristor according to the first control instruction; an input end of the relay drive circuit is electrically connected to the I / O port of the control chip, an output end of the relay drive circuit is electrically connected to the relay, and the relay drive circuit is configured to receive a second control instruction from the control chip and control disconnection and closure of the relay according to the second control instruction.

[0008] Preferably, the heating control circuit further includes: a load open-circuit detection circuit, and the load open-circuit detection circuit is electrically connected to the I / O port of the control chip; the load open-circuit detection circuit is configured to detect whether there is a load open-circuit in the heating control circuit.

[0009] Preferably, the first preset condition is that: the heating control circuit switches from a high-power heating state to a low-power heating state; the second preset condition is that: the heating control circuit switches from a low-power heating state to a high-power heating state.

[0010] Preferably, the zero-crossing detection circuit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first diode, a first transistor, and a first capacitor; a first end of the first resistor is connected to an input end of the zero-crossing detection circuit, and a second end of the first resistor is connected to a first end of the second resistor; a first end of the third resistor is connected to a second end of the second resistor, and a second end of the third resistor is grounded; a cathode of the first diode is connected to the first end of the third resistor, and an anode of the first diode is grounded; a first end of the first transistor is connected to the cathode of the first diode, a second end of the first transistor is connected to a second end of the fourth resistor and a first end of the fifth resistor, and a third end of the first transistor is grounded; a first end of the fourth resistor is connected to an external first DC regulated power supply; a first end of the first capacitor is connected to a second end of the fifth resistor and an output end of the zero-crossing detection circuit, and a second end of the first capacitor is grounded.

[0011] Preferably, the first transistor is an NPN-type triode; the first end of the first transistor is the base, the second end of the first transistor is the collector, and the third end of the first transistor is the emitter.

[0012] Preferably, the thyristor drive circuit includes: a sixth resistor, a second capacitor, a seventh resistor, a second transistor, an eighth resistor, a ninth resistor, a third transistor, a tenth resistor, a third capacitor, and an eleventh resistor; a first end of the sixth resistor is connected to a first end of the thyristor, and a second end of the sixth resistor is connected to a control end of the thyristor; the second capacitor is connected in parallel with the sixth resistor; a first end of the seventh resistor is connected to a second end of the second capacitor, and a second end of the seventh resistor is connected to a second end of the second transistor; a first end of the second transistor is connected to a first end of the eighth resistor and a first end of the ninth resistor, and a third end of the second transistor is connected to a second end of the eighth resistor and an external second DC regulated power supply; a first end of the third transistor is connected to a second end of the tenth resistor, a second end of the third transistor is connected to a second end of the ninth resistor, and a third end of the third transistor is connected to a first end of the tenth resistor and a ground terminal; the third capacitor is connected in parallel with the tenth resistor; a first end of the eleventh resistor is connected to a first end of the third transistor, and a second end of the eleventh resistor is connected to a signal input terminal of the thyristor drive circuit.

[0013] Preferably, the relay drive circuit includes: a second diode, a fourth transistor, a twelfth resistor, and a thirteenth resistor, wherein; the second diode is connected in parallel to two ends of the coil of the relay; a first end of the fourth transistor is connected to a second end of the twelfth resistor, a second end of the fourth transistor is connected to an anode of the second diode, and a third end of the fourth transistor is connected to a first end of the twelfth resistor and a ground terminal; a first end of the thirteenth resistor is connected to a second end of the twelfth resistor, and a second end of the thirteenth resistor is connected to a signal input terminal of the relay drive circuit.

[0014] Preferably, the load open - circuit detection circuit includes: a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a fourth capacitor, a third diode, a fifth transistor, a seventeenth resistor, an eighteenth resistor, and a fifth capacitor; a first end of the fourteenth resistor is connected to a detection end of the load open - circuit detection circuit, and a second end of the fourteenth resistor is connected to a first end of the fifteenth resistor; a first end of the sixteenth resistor is connected to a second end of the fifteenth resistor, and a second end of the sixteenth resistor is grounded; the fourth capacitor is connected in parallel with the sixteenth resistor, and the three - diode is connected in parallel with the fourth capacitor; a first end of the fifth transistor is connected to a cathode of the third diode, a second end of the fifth transistor is connected to a first end of the eighteenth resistor, and a third end of the fifth transistor is grounded; a first end of the seventeenth resistor is connected to an external first DC regulated power supply, and a second end of the seventeenth resistor is connected to the second end of the fifth transistor; a first end of the fifth capacitor is connected to a second end of the eighteenth resistor, and a second end of the fifth capacitor is grounded.

[0015] In a second aspect, the present application also provides an electric kettle, including a kettle body and a kettle base, and the above - mentioned heating control circuit is provided on the kettle base.

[0016] Compared with the prior art, the present application has the following technical effects: The heating control circuit of the present application can be applied to an electric kettle. The control chip controls the heating wire by controlling the thyristor and the relay connected in parallel. When the power of the heating control circuit meets the first preset condition, the control chip controls the thyristor to conduct according to the zero - crossing point of the zero - crossing detection circuit, and after the thyristor conducts, controls the relay to disconnect, so as to reduce the frequent load - starting and stopping of the relay; when the power of the heating control circuit meets the second preset condition, the control chip controls the relay to close, and after the relay closes, controls the thyristor to cut off according to the zero - crossing point of the zero - crossing detection circuit to achieve rapid heating. Through the technical solution of the present application, the problem of arc ablation of the relay contacts caused by the load - starting and stopping of the relay can be solved, and thus the service life of the relay can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the architecture of a heating control circuit according to an embodiment of the present application;

[0018] Figure 2 is a schematic diagram of the architecture of another heating control circuit according to an embodiment of the present application;

[0019] Figure 3 is a schematic diagram of the architecture of yet another heating control circuit according to an embodiment of the present application;

[0020] Figure 4 is a schematic diagram of the structure of the zero - crossing detection circuit in an embodiment of the present application;

[0021] Figure 5 is a schematic structural diagram of the thyristor drive circuit in the embodiment of the present application;

[0022] Figure 6 is a schematic structural diagram of the relay drive circuit in the embodiment of the present application;

[0023] Figure 7 is a schematic structural diagram of the load open - circuit detection circuit in the embodiment of the present application.

[0024] Description of the reference numerals: 100, heating control circuit; 1O, control chip; 20, relay; 30, thyristor; 40, zero - crossing detection circuit; 50, relay drive circuit; 60, thyristor drive circuit; RX1, first resistor; RX2, second resistor; RX3, third resistor; R9, fourth resistor; R11, fifth resistor; D4, first diode; Q1, first transistor; C6, first capacitor; R27, sixth resistor; C8, second capacitor; R30, seventh resistor; Q3, second transistor; R31, eighth resistor; R35, ninth resistor; Q4, third transistor; R28, tenth resistor; C9, third capacitor; R33, eleventh resistor; D5, second diode; Q6, fourth transistor; R40, twelfth resistor; R48, thirteenth resistor; RX4, fourteenth resistor; RX5, fifteenth resistor; RX6, sixteenth resistor; C29, fourth capacitor; D6, third diode; Q7, fifth transistor; R56, seventeenth resistor; R62, eighteenth resistor; C25, fifth capacitor. Detailed implementation manners

[0025] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts belong to the scope of protection of the present application.

[0026] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. On the contrary, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration.

[0027] In this application, unless otherwise clearly defined and limited, terms such as "install", "connect", "link", "fix", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0028] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "a plurality" is two or more, unless otherwise clearly and specifically defined.

[0029] The terms used in one or more embodiments of this application are only for the purpose of describing specific embodiments and are not intended to limit one or more embodiments of this application. The singular forms of "a", "the", and "said" used in one or more embodiments of this application are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this template are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] It should be understood that although the terms first, second, etc. may be used in one or more embodiments of this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of this application, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. Depending on the context, the word "if" as used herein can be interpreted as "when" or "while".

[0032] Please refer to Figure 1 , an embodiment of this application provides a heating control circuit, which can be applied to an electric kettle. Specifically, it can be applied to the kettle base of the electric kettle. The heating control circuit includes: a control chip 10, a relay 20, a thyristor 30, and a zero-crossing detection circuit 40.

[0033] It should be noted that the thyristor 30 is a high-power semiconductor device with a four-layer structure having three PN junctions, also known as a thyristor. It has the characteristics of small volume, relatively simple structure, strong functions, etc., and is one of the relatively commonly used semiconductor devices. This device is widely used in various electronic devices and electronic products, and is mostly used for controllable rectification, inversion, frequency conversion, voltage regulation, non-contact switches, etc.

[0034] The relay 20 is an electrical control device with contacts. When the change of the input quantity (excitation quantity) reaches the specified requirement, it is an electrical appliance that causes a predetermined step change in the controlled quantity in the electrical output circuit. It has an interaction relationship between the control system (also known as the input circuit) and the controlled system (also known as the output circuit). It is usually applied to the automatic control circuit. It is actually an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays roles such as automatic regulation, safety protection, and circuit conversion in the circuit.

[0035] It should be noted that for the relay 20, the number of times its contacts are used is limited, and when the relay 20 starts and stops with a load, electric arcs will be generated on the contacts, which will further affect the service life of the contacts of the relay 20.

[0036] There are multiple I / O ports on the control chip 10. The relay 20 and the thyristor 30 are connected in parallel, and the relay 20 and the thyristor 30 are electrically connected to different I / O ports of the control chip 10. The control chip 10 is used to control the working states of the relay 20 and the thyristor 30.

[0037] It should be noted that the control methods of the thyristor 20 are generally divided into PWM chopper control and dropout control with the time interval between AC zero-crossings as the cycle. In this embodiment, dropout control with the time interval between AC zero-crossings as the cycle is adopted.

[0038] It can be understood that there are multiple I / O ports on the control chip 10 for connecting to different electronic components. The control chip receives signals from different electronic components or sends control signals to different electronic components through these I / O ports.

[0039] In this embodiment, the relay 20 and the thyristor 30 are electrically connected to different I / O ports on the control chip 10. The control chip 10 can send corresponding control signals to the relay 20 and the thyristor 30 through the I / O ports to realize the control of the working states of the relay 20 and the thyristor 30 by the control chip 10.

[0040] It should be noted that when the relay 20 starts and stops with a load, electric arcs will be generated on the contacts, which will further reduce the service life of the contacts of the relay 20. In this embodiment, by designing a parallel connection structure for the relay 20 and the thyristor 30, when the relay 20 starts, the thyristor 30 can be made to conduct first, and then the relay 20 can be closed. Similarly, when the relay 20 stops working, the thyristor 30 can also be made to conduct first, and then the relay 20 can be disconnected, so as to avoid the relay 20 starting and stopping with a load.

[0041] The input end of the zero-crossing detection circuit 40 is electrically connected to an external AC power supply, and the output end of the zero-crossing detection circuit 40 is electrically connected to the I / O port of the control chip 10; the zero-crossing detection circuit 40 is used to provide a switching signal for the control chip 10 to switch the working states of the relay 20 and the thyristor 30.

[0042] Wherein, when the power of the heating control circuit 100 meets the first preset condition, the control chip 10 controls the thyristor 30 to conduct and controls the relay 20 to disconnect; when the power of the heating control circuit 100 meets the second preset condition, the control chip 10 controls the relay to close and controls the thyristor 30 to cut off.

[0043] Specifically, the input end of the zero-crossing detection circuit 40 is connected to an external AC power supply, which is used to detect the zero-crossing point in the alternating current and send the electrical signal of the zero-crossing point to the control chip 10 through the output end, so that the control chip 10 can switch the working states of the relay 20 and the thyristor 30 according to the zero-crossing signal.

[0044] In some alternative embodiments, the first preset condition is that the heating control circuit 100 switches from a high-power heating state to a low-power heating state; the second preset condition is that the heating control circuit 100 switches from a low-power heating state to a high-power heating state.

[0045] Exemplarily, when the heating control circuit 100 is applied to an electric kettle, when the electric kettle changes from the heating state to the heat preservation state, since it is in the heat preservation state, the heating control circuit only needs to output a low power to maintain the heat preservation state. At this time, the relay 20 in the heating control circuit 100 can be controlled to heat by the thyristor 30. Conversely, the thyristor 30 in the heating control circuit 100 can be controlled to heat by the relay 20.

[0046] The heating control circuit 100 of the present application can be applied to an electric kettle. The control chip 10 controls the heating wire through the thyristor 30 and the relay 20 connected in parallel. When the power of the heating control circuit 100 meets the first preset condition, the control chip 10 controls the thyristor 30 to conduct according to the zero-crossing point of the zero-crossing detection circuit 40, and after the thyristor 30 conducts, controls the relay 20 to disconnect, so as to reduce the frequent load-on and load-off of the relay 20; when the power of the heating control circuit 100 meets the second preset condition, the control chip 10 controls the relay 20 to close, and after the relay 20 closes, controls the thyristor 30 to cut off according to the zero-crossing point of the zero-crossing detection circuit 40 to achieve rapid heating. Through the technical solution of the present application, the problem of arc ablation of the contacts of the relay 20 caused by the load-on and load-off of the relay 20 can be solved, and thus the service life of the relay 20 can be improved.

[0047] Please refer to Figure 2 In some alternative embodiments, the heating control circuit 100 further includes: a thyristor drive circuit 60 and a relay drive circuit 50; the input end of the thyristor drive circuit 60 is electrically connected to the I / O port of the control chip 10, the output end of the thyristor drive circuit 60 is electrically connected to the thyristor 30, and the thyristor drive circuit 60 is configured to receive the first control instruction of the control chip 10 and control the conduction and cut-off of the thyristor 30 according to the first control instruction; the input end of the relay drive circuit 50 is electrically connected to the I / O port of the control chip 10, the output end of the relay drive circuit 50 is electrically connected to the relay 20, and the relay drive circuit 50 is configured to receive the second control instruction of the control chip 10 and control the disconnection and closure of the relay 20 according to the second control instruction.

[0048] Exemplarily, the working process of the thyristor drive circuit 60 is as follows: the control chip 10 sends the first control instruction to the thyristor drive circuit 60, and the thyristor drive circuit 60 controls the working state of the thyristor 30 according to the first control instruction. Similarly, the working process of the relay drive circuit 50 is as follows: the control chip 10 sends the second control instruction to the relay drive circuit 50, and the relay drive circuit 50 controls the working state of the relay 20 according to the second control instruction.

[0049] In this embodiment, the heating control circuit 100 is configured to amplify the control signal sent from the control chip 10 to the thyristor 30 by setting a thyristor drive circuit 60 between the control chip 10 and the thyristor 30, so that the control signal can drive the thyristor 30 to conduct and cut off. Similarly, the heating control circuit 100 is configured to amplify the control signal sent from the control chip 10 to the relay 20 by setting a relay drive circuit 50 between the control chip 10 and the relay 30, so that the control signal can drive the relay 20 to close and open.

[0050] Please refer to Figure 3 , in some alternative embodiments, the heating control circuit 100 further includes: a load open - circuit detection circuit 70, which is electrically connected to the I / O port of the control chip 10; the load open - circuit detection circuit 70 is configured to detect whether there is a load open - circuit in the heating control circuit.

[0051] Exemplarily, the working process of the load open - circuit detection circuit is as follows: the load open - circuit detection circuit 70 can judge whether there is a load open - circuit in the heating control circuit 100 by detecting the voltage and / or current in the heating control circuit 100. If there is a load open - circuit, a corresponding signal will be transmitted to the control chip 10. After receiving the detection signal of the load open - circuit detection, the control chip 10 can take corresponding protection measures, such as shutting down the power supply, sending out a warning signal, etc., to protect the safety of the device and the operator.

[0052] Please refer to Figure 4 , in some alternative embodiments, the zero - crossing detection circuit 40 includes: a first resistor RX1, a second resistor RX2, a third resistor RX3, a fourth resistor R9, a fifth resistor R11, a first diode D4, a first transistor Q1, and a first capacitor C6; the first end of the first resistor RX1 is connected to the input end of the zero - crossing detection circuit 40, and the second end of the first resistor RX1 is connected to the first end of the second resistor RX2; the first end of the third resistor RX3 is connected to the second end of the second resistor RX2, and the second end of the third resistor RX3 is grounded; the cathode of the first diode D4 is connected to the first end of the third resistor RX3, and the anode of the first diode D4 is grounded; the first end of the first transistor Q1 is connected to the cathode of the first diode D4, the second end of the first transistor Q1 is connected to the second end of the fourth resistor and the first end of the fifth resistor R11, and the third end of the first transistor Q1 is grounded; the first end of the fourth resistor R9 is connected to an external first DC regulated power supply; the first end of the first capacitor C6 is connected to the second end of the fifth resistor R11 and the output end of the zero - crossing detection circuit 40, and the second end of the first capacitor C6 is grounded.

[0053] Specifically, the working process of the zero-crossing detection circuit 40 is as follows: The detection points of the zero-crossing detection circuit 40 are respectively connected to the output terminals of the external AC power supply. In each sine wave cycle of the external AC power supply, when the sine wave at the AC-Check terminal (the detection terminal of the zero-crossing detection circuit 40) drops and the sine voltage is lower than the conduction voltage of the BE junction of the first transistor Q1, the first transistor Q1 is cut off, and the Zero terminal (the output terminal of the zero-crossing detection circuit) outputs a high level. The current in the external first DC regulated power supply flows through the fourth resistor R9 and the fifth resistor R11 to the Zero terminal. The Zero terminal is connected to the I / O port of the control chip 10, and the control chip 10 obtains a high-level signal, thereby obtaining the zero-crossing point of the power supply sine wave. When the sine wave at the AC-Check terminal rises and the sine voltage is higher than the conduction voltage of the BE junction of the first transistor Q1, the first transistor Q1 conducts, the Zero terminal outputs a low level, and the current in the external DC regulated power supply flows through the fourth resistor R9 and the fifth resistor R11 to VSS (ground terminal), and the high level at the I / O port of the control chip 10 disappears. At this time, the sine wave is at a non-zero point.

[0054] In this embodiment, the heating control circuit 100 detects the zero-crossing point of the alternating current in the circuit by setting the zero-crossing detection circuit 40. When the zero-crossing detection circuit 40 detects the zero-crossing point of the alternating current, it will transmit the zero-crossing signal to the control chip 10, so that the control chip 10 can judge whether to switch the working states of the thyristor 30 and / or the relay 20 according to the zero-crossing point signal.

[0055] In some alternative embodiments, the first transistor Q1 is an NPN-type triode; the first end of the first transistor Q1 is the base, the second end of the first transistor Q1 is the collector, and the third end of the first transistor Q1 is the emitter.

[0056] In some alternative embodiments, please refer to Figure 5, the thyristor drive circuit 60 includes: a sixth resistor R27, a second capacitor C8, a seventh resistor R30, a second transistor Q3, an eighth resistor R31, a ninth resistor R35, a third transistor Q4, a tenth resistor R28, a third capacitor C9, and an eleventh resistor R33; a first end of the sixth resistor R27 is connected to a first end of the thyristor 30, and a second end of the sixth resistor R27 is connected to a control end of the thyristor; the second capacitor C8 is connected in parallel with the sixth resistor R27; a first end of the seventh resistor R30 is connected to a second end of the second capacitor C8, and a second end of the seventh resistor R30 is connected to a second end of the second transistor Q3; a first end of the second transistor Q3 is connected to a first end of the eighth resistor R31 and a first end of the ninth resistor, and a third end of the second transistor Q3 is connected to a second end of the eighth resistor R31 and an external second DC regulated power supply; a first end of the third transistor Q4 is connected to a second end of the tenth resistor R28, a second end of the third transistor Q4 is connected to a second end of the ninth resistor R35, and a third end of the third transistor Q4 is connected to a first end of the tenth resistor R28 and a ground terminal; the third capacitor C9 is connected in parallel with the tenth resistor R28; a first end of the eleventh resistor R33 is connected to a first end of the third transistor Q4, and a second end of the eleventh resistor R33 is connected to a signal input terminal of the thyristor drive circuit 60.

[0057] It should be noted that the thyristor 30 is a current-driven high-speed switching component. When the current between the control end (G end) of the thyristor 30 and the first end of the thyristor 30 is greater than the drive current required by the component, the anode terminal and the cathode terminal of the thyristor 30 are turned on; the external second DC regulated power supply can be set according to the actual situation, for example, it can be 5V, 3.3V, etc.

[0058] In this embodiment, the first end of the thyristor 30 can be an input terminal (anode) or an output terminal (cathode). When the first end of the thyristor 30 is an input terminal, the second end of the thyristor 30 is an output terminal; when the first end of the thyristor 30 is an output terminal, the second end of the thyristor 30 is an input terminal.

[0059] Exemplarily, the working process of the thyristor drive circuit 60 is as follows: the I / O port of the control chip 10 injects a high level into the Triac terminal (the information input terminal of the thyristor drive circuit 60) to turn on the third transistor Q4, and the second transistor Q3 is driven to turn on simultaneously by the conduction of the third transistor Q4. After the second transistor Q3 is turned on, it provides a conduction drive current for the thyristor 30, thereby turning on the thyristor 30.

[0060] In this embodiment, the heating control circuit 100 controls the conduction and cut-off of the thyristor 30 by setting the thyristor drive circuit 60. When it is necessary for the thyristor 30 to conduct, the I / O port of the control chip 10 inputs a high-level signal to the thyristor drive circuit 60. Conversely, the I / O port of the control chip 10 inputs a low-level signal to the thyristor drive circuit 60. Through the thyristor drive circuit 60 in this embodiment, the conduction and cut-off of the thyristor 30 can be quickly controlled, thereby realizing the control and adjustment of the circuit.

[0061] In some alternative embodiments, please refer to Figure 6 , the relay drive circuit 50 includes: a second diode D5, a fourth transistor Q6, a twelfth resistor R40, and a thirteenth resistor R48; the second diode D5 is connected in parallel to both ends of the coil of the relay 20; the first end of the fourth transistor Q6 is connected to the second end of the twelfth resistor R40, the second end of the fourth transistor Q6 is connected to the anode of the second diode D5, and the third end of the fourth transistor Q6 is connected to the first end of the twelfth resistor R40 and the ground terminal; the first end of the thirteenth resistor R48 is connected to the second end of the twelfth resistor R40, and the second end of the thirteenth resistor R48 is connected to the signal input terminal of the relay drive circuit 50.

[0062] It should be noted that since the relay 20 is inserted after the thyristor 30, there is no need for a zero-crossing signal for coordinated drive. Its starting principle is that the I / O port of the control chip 10 injects a high level into the Relay terminal (the signal input terminal of the relay drive circuit 50) to make the fourth transistor Q6 conduct. After the fourth transistor Q6 conducts, the relay 20 is then attracted.

[0063] In this embodiment, the heating control circuit 100 controls the closing and opening of the relay 20 by setting the relay drive circuit 50. When it is necessary for the relay 20 to conduct, the I / O port of the control chip 10 inputs a high-level signal to the relay drive circuit 50. Conversely, the I / O port of the control chip 10 inputs a low-level signal to the relay drive circuit 50. Through the relay drive circuit 50 in this embodiment, the closing and opening of the relay 30 can be quickly controlled, thereby realizing the control and adjustment of the circuit.

[0064] In some alternative embodiments, please refer to Figure 7, the load open - circuit detection circuit 70 includes: the fourteenth resistor RX4, the fifteenth resistor RX5, the sixteenth resistor RX6, the fourth capacitor C29, the third diode D6, the fifth transistor Q7, the seventeenth resistor R56, the eighteenth resistor R62, and the fifth capacitor C25; the first end of the fourteenth resistor RX4 is connected to the detection end of the load open - circuit detection circuit 70, and the second end of the fourteenth resistor RX4 is connected to the first end of the fifteenth resistor RX5; the first end of the sixteenth resistor RX6 is connected to the second end of the fifteenth resistor, and the second end of the sixteenth resistor RX6 is grounded; the fourth capacitor C29 is in parallel with the sixteenth resistor RX6, and the three - diode D6 is in parallel with the fourth capacitor C29; the first end of the fifth transistor Q7 is connected to the cathode of the third diode D6, the second end of the fifth transistor D6 is connected to the first end of the eighteenth resistor R62, and the third end of the fifth transistor Q7 is grounded; the first end of the seventeenth resistor R56 is connected to the first DC regulated power supply, and the second end of the seventeenth resistor R56 is connected to the second end of the fifth transistor Q7; the first end of the fifth capacitor C25 is connected to the second end of the eighteenth resistor R62, and the second end of the fifth capacitor C25 is grounded.

[0065] It should be noted that Figure 7 the HT - Check terminal in is connected to the I / O port of the control chip 10, VSS is the ground terminal, and the voltage of the external first DC regulated power supply can be set to 3.3V.

[0066] In this embodiment, the load open - circuit detection circuit 70 monitors the load in the heating control circuit 100 in real - time. When a load open - circuit occurs, it can send a load open - circuit signal to the control chip 10, so that the control chip 10 can trigger corresponding processing measures, such as shutting down the power supply, sending out warning signals, etc., to protect the safety of the device and the operator.

[0067] The embodiment of the present application also provides an electric kettle, which includes a kettle body and a kettle base, and the kettle base is provided with the above - mentioned heating control circuit 100.

[0068] In this embodiment, the heating control circuit 100 is provided on the kettle base of the electric kettle. Since the heating control circuit 100 includes two ways of controlling heating, that is, the relay 20 controls heating and the thyristor 30 controls heating. Compared with the electric kettle that only uses the relay 20 for heating control, the electric kettle in this example is more flexible in controlling heating and can avoid the arc hazard caused by the frequent start - stop of the relay 20, thereby making the service life of the electric kettle longer.

[0069] In all of the examples shown and described herein, any specific values should be construed as merely exemplary and not as limitations. Thus, other examples of the exemplary embodiments may have different values.

[0070] It should be noted that like reference numerals and letters refer to like items in the following figures. Thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

[0071] In addition, each functional module or unit in various embodiments of the present application may be integrated together to form an independent part, or each module may exist alone, or two or more modules may be integrated to form an independent part.

[0072] As described above, the foregoing are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application.

Claims

1. A heating control circuit, characterized in that: include: Control chip, relay, thyristor and zero-crossing detection circuit; The control chip has a plurality of I / O ports, the relay is connected in parallel with the thyristor, the relay and the thyristor are electrically connected to different I / O ports of the control chip, and the control chip is used to control the working state of the relay and the working state of the thyristor; The input end of the zero-crossing detection circuit is electrically connected to an external AC power supply, and the output end of the zero-crossing detection circuit is electrically connected to an I / O port of the control chip; the zero-crossing detection circuit is used to provide a switching signal for the control chip to switch the working state of the relay and the working state of the thyristor; Wherein, when the power of the heating control circuit meets the first preset condition, the control chip controls the thyristor to be turned on, and controls the relay to be turned off; When the power of the heating control circuit meets the second preset condition, the control chip controls the relay to close and controls the thyristor to cut off.

2. The heating control circuit according to claim 1, characterized in that: The heating control circuit also includes: a thyristor drive circuit and a relay drive circuit; The input end of the thyristor drive circuit is electrically connected to the I / O port of the control chip, the output end of the thyristor drive circuit is electrically connected to the thyristor, and the thyristor drive circuit is used to receive a first control instruction of the control chip and control the conduction and cutoff of the thyristor according to the first control instruction; The input end of the relay drive circuit is electrically connected to the I / O port of the control chip, and the output end of the relay drive circuit is electrically connected to the relay. The relay drive circuit is used to receive the second control instruction of the control chip and control the opening and closing of the relay according to the second control instruction.

3. The heating control circuit according to claim 1, characterized in that: The heating control circuit further includes: a load open circuit detection circuit, wherein the load open circuit detection circuit is electrically connected to the I / O port of the control chip; The load open circuit detection circuit is used to detect whether there is a load open circuit in the heating control circuit.

4. The heating control circuit according to claim 1, characterized in that: The first preset condition is that the heating control circuit switches from a high-power heating state to a low-power heating state; the second preset condition is that the heating control circuit switches from a low-power heating state to a high-power heating state.

5. The heating control circuit according to claim 1, characterized in that: The zero-crossing detection circuit comprises: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first diode, a first transistor and a first capacitor; The first end of the first resistor is connected to the input end of the zero-crossing detection circuit, and the second end of the first resistor is connected to the first end of the second resistor; The first end of the third resistor is connected to the second end of the second resistor, and the second end of the third resistor is grounded; The cathode of the first diode is connected to the first end of the third resistor, and the anode of the first diode is grounded; A first end of the first transistor is connected to the cathode of the first diode, a second end of the first transistor is connected to the second end of the fourth resistor and the first end of the fifth resistor, and a third end of the first transistor is grounded; The first end of the fourth resistor is connected to an external first DC regulated power supply; A first end of the first capacitor is connected to a second end of the fifth resistor and an output end of the zero-crossing detection circuit, and a second end of the first capacitor is grounded.

6. The heating control circuit according to claim 5, characterized in that: The first transistor is an NPN-type triode; the first end of the first transistor is a base, the second end of the first transistor is a collector, and the third end of the first transistor is an emitter.

7. The heating control circuit according to claim 2, characterized in that: The thyristor driving circuit includes: a sixth resistor, a second capacitor, a seventh resistor, a second transistor, an eighth resistor, a ninth resistor, a third transistor, a tenth resistor, a third capacitor and an eleventh resistor; The first end of the sixth resistor is connected to the first end of the thyristor, and the second end of the sixth resistor is connected to the control end of the thyristor; The second capacitor is connected in parallel with the sixth resistor; The first end of the seventh resistor is connected to the second end of the second capacitor, and the second end of the seventh resistor is connected to the second end of the second transistor; The first end of the second transistor is connected to the first end of the eighth resistor and the first end of the ninth resistor, and the third end of the second transistor is connected to the second end of the eighth resistor and an external second DC regulated power supply; The first end of the third transistor is connected to the second end of the tenth resistor, the second end of the third transistor is connected to the second end of the ninth resistor, and the third end of the third transistor is connected to the first end of the tenth resistor and the ground end; The third capacitor is connected in parallel with the tenth resistor; The first end of the eleventh resistor is connected to the first end of the third transistor, and the second end of the eleventh resistor is connected to the signal input end of the thyristor driving circuit.

8. The heating control circuit according to claim 2, characterized in that: The relay driving circuit comprises: a second diode, a fourth transistor, a twelfth resistor and a thirteenth resistor; The second diode is connected in parallel to two ends of the coil of the relay; The first end of the fourth transistor is connected to the second end of the twelfth resistor, the second end of the fourth transistor is connected to the anode of the second diode, and the third end of the fourth transistor is connected to the first end of the twelfth resistor and the ground end; The first end of the thirteenth resistor is connected to the second end of the twelfth resistor, and the second end of the thirteenth resistor is connected to the signal input end of the relay driving circuit.

9. The heating control circuit according to claim 3, characterized in that: The load open circuit detection circuit comprises: a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a fourth capacitor, a third diode, a fifth transistor, a seventeenth resistor, an eighteenth resistor and a fifth capacitor; The first end of the fourteenth resistor is connected to the detection end of the load open circuit detection circuit, and the second end of the fourteenth resistor is connected to the first end of the fifteenth resistor; The first end of the sixteenth resistor is connected to the second end of the fifteenth resistor, and the second end of the sixteenth resistor is grounded; The fourth capacitor is connected in parallel with the sixteenth resistor, and the three diodes are connected in parallel with the fourth capacitor; A first terminal of the fifth transistor is connected to the cathode of the third diode, a second terminal of the fifth transistor is connected to the first terminal of the eighteenth resistor, and a third terminal of the fifth transistor is grounded; The first end of the seventeenth resistor is connected to the external first DC regulated power supply, and the second end of the seventeenth resistor is connected to the second end of the fifth transistor; A first end of the fifth capacitor is connected to a second end of the eighteenth resistor, and a second end of the fifth capacitor is grounded.

10. An electric kettle, characterized in that: The invention comprises a kettle body and a kettle base, wherein the kettle base is provided with a heating control circuit as claimed in any one of claims 1 to 9.

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