Control circuit and air fryer

Abstract

The utility model discloses a control circuit and an air fryer, and relates to the technical field of household appliances, the control circuit comprises an isolation power supply circuit, a display control circuit and a heating circuit, the display control circuit comprises a touchable display screen, the display control circuit is electrically connected with the isolation power supply circuit, and the heating circuit is electrically connected with the isolation power supply circuit. The heating circuit is electrically connected with an external alternating current power supply and the display control circuit. An external alternating-current power source is converted into a direct-current power source through an isolation power source circuit, the direct-current power source is output to a display control circuit in an isolated mode to supply power to the display control circuit, and the display control circuit can output a heating control signal to a heating circuit so that the heating circuit can conduct or disconnect a heating loop of the external alternating-current power source to the air fryer according to the heating control signal. Thus, electrical isolation is achieved between the display control circuit and the external alternating current power source, when a user controls the working state of the air fryer through the touchable display screen, harm to the user under the condition of circuit faults or misoperation can be effectively prevented, and the safety of the air fryer is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of household appliances, in particular to a control circuit and an air fryer. Background Art

[0002] With the advancement of technology and the improvement of people's living standards, kitchen appliances are constantly being updated. Among them, air fryers, as a new type of cooking tool, are gradually favored by consumers because of their health, convenience and speed. The working principle of air fryers is to use high-speed circulating hot air instead of traditional frying oil, and use a mechanical fan to circulate the hot air around the food at high speed, thereby achieving the purpose of cooking food.

[0003] However, most air fryers currently use non-isolated power supplies to drive external knobs or buttons to control the working status, and the above design has certain safety hazards. Utility Model Content

[0004] The main purpose of the utility model is to provide a control circuit and an air fryer, aiming to improve the safety of the air fryer.

[0005] To achieve the above object, the control circuit proposed in the utility model is applied to an air fryer, and the control circuit comprises:

[0006] An isolated power supply circuit; the isolated power supply circuit is used to convert an external AC power supply into a DC power supply and isolate the output;

[0007] A display control circuit, comprising a touch display screen, the display control circuit being electrically connected to the isolated power supply circuit; the display control circuit being used to display the working state of the air fryer and output a control signal to control the working state of the air fryer;

[0008] A heating circuit, wherein the heating circuit is electrically connected to the external AC power supply and the display control circuit respectively; the control signal includes a heating control signal, and the heating circuit is used to turn on or off the heating circuit of the air fryer by the external AC power supply according to the heating control signal.

[0009] In one embodiment, the air fryer further includes a furnace door, and the control circuit further includes:

[0010] An oven door detection circuit, the oven door detection circuit being electrically connected to the external AC power supply and the display control circuit respectively; the oven door detection circuit is used to detect the switch state of the oven door, generate a corresponding oven door detection signal and output it to the display control circuit;

[0011] The display control circuit is also used to output a heating control signal to the heating circuit when the oven door is in an open state, so as to disconnect the heating circuit of the air fryer from the external AC power supply.

[0012] In one embodiment, the isolated power supply circuit includes:

[0013] A rectifier circuit, the rectifier circuit is connected to an external AC power source; the rectifier circuit is used to rectify the external AC power source into a DC power source;

[0014] A transformer circuit, the transformer circuit is connected to the rectifier circuit; the transformer circuit is used to isolate and output the DC power supply.

[0015] In one embodiment, the voltage conversion circuit includes a transformer;

[0016] The isolated power supply circuit also includes a power supply protection circuit, and the power supply protection circuit is electrically connected to the transformer.

[0017] In one embodiment, the transformer circuit further includes a pulse protection circuit, which is connected in parallel with the primary coil of the transformer; the pulse protection circuit is used to absorb the high-voltage pulse generated by the transformer when the power supply to the primary coil of the transformer is disconnected.

[0018] In one embodiment, the isolated power supply circuit further includes a power regulating circuit, which is electrically connected to the power supply protection circuit and the transformer respectively; the power regulating circuit is used to regulate the output power of the isolated power supply circuit.

[0019] In one embodiment, the control circuit also includes a temperature detection circuit, which is electrically connected to the display control circuit; the temperature detection circuit is used to detect the temperature inside the air fryer, generate a temperature detection signal, and output it to the display control circuit.

[0020] In one embodiment, the air fryer further includes a fan and an oven light, and the control circuit further includes:

[0021] A fan circuit, the fan circuit is electrically connected to the display control circuit; the control signal also includes a fan control signal; the fan circuit is used to control the rotation speed of the fan according to the fan control signal.

[0022] and / or,

[0023] A furnace lamp circuit, the furnace lamp circuit is electrically connected to the display control circuit; the control signal also includes a furnace lamp control signal; the furnace lamp circuit is used to control the brightness of the furnace lamp according to the furnace lamp control signal.

[0024] In one embodiment, the control circuit further includes:

[0025] A buzzer circuit is electrically connected to the display control circuit; the control signal also includes a buzzer control signal; the buzzer circuit is used to issue a sound prompt according to the buzzer control signal.

[0026] The utility model also provides an air fryer, which comprises the control circuit.

[0027] The technical solution of the utility model adopts an isolated power supply circuit, a display control circuit and a heating circuit. The display control circuit includes a touch screen, and the display control circuit is electrically connected to the isolated power supply circuit. The heating circuit is electrically connected to the external AC power supply and the display control circuit respectively. The external AC power supply is converted into a DC power supply through the isolated power supply circuit, and the output is isolated to the display control circuit to supply power for the display control current. The display control circuit can output a heating control signal to the heating circuit, so that the heating circuit can turn on or off the heating circuit of the air fryer by the external AC power supply according to the heating control signal. In this way, electrical isolation is achieved between the display control circuit and the external AC power supply. When the user controls the working state of the air fryer through the touch screen, it can effectively prevent the circuit failure or misoperation from causing harm to the user, thereby improving the safety of the air fryer. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the structure of an embodiment of a control circuit provided by the utility model;

[0030] Figure 2 A schematic diagram of the structure of another embodiment of the control circuit provided by the utility model;

[0031] Figure 3 A structural schematic diagram of another embodiment of the control circuit provided by the utility model;

[0032] Figure 4 A structural schematic diagram of another embodiment of the control circuit provided by the utility model;

[0033] Figure 5 A structural schematic diagram of another embodiment of the control circuit provided by the utility model;

[0034] Figure 6 A schematic diagram of the structure of another embodiment of the control circuit provided by the utility model;

[0035] Figure 7 A structural schematic diagram of another embodiment of the control circuit provided by the utility model;

[0036] Figure 8 A structural schematic diagram of another embodiment of the control circuit provided by the utility model;

[0037] Fig. 9 This is a structural schematic diagram of another embodiment of the control circuit provided by the utility model.

[0038] Description of Figure Numbers:

[0039] 10. Isolation power supply circuit; 20. Display control circuit; 30. Heating circuit; 11. Rectification circuit; 12. Voltage conversion circuit; 13. Power protection circuit; U33. Rectification bridge; T3. Transformer; EC1. First filter capacitor; EC2. Second filter capacitor; U32. Power protection chip; R40. First resistor; R71. Second resistor; R41. Third resistor; C10. First capacitor; D8. First diode, F1. Fuse; EC5. Second capacitor; EC6. Third capacitor; R79. Magnetic bead; R60. Fourth resistor; R61. Fifth resistor; K1. Relay; U16. First optocoupler chip; R48. Sixth resistor; Q1. First switch tube; U1. Second optocoupler chip; Q6. Second switch tube; U34. Third optocoupler chip; U15. Buzzer.

[0040] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0042] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0043] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0044] With the advancement of technology and the improvement of people's living standards, kitchen appliances are constantly being updated. Among them, air fryers, as a new type of cooking tool, are gradually favored by consumers because of their health, convenience and speed. The working principle of air fryers is to use high-speed circulating hot air instead of traditional frying oil, and use a mechanical fan to circulate the hot air around the food at high speed, thereby achieving the purpose of cooking food.

[0045] However, most air fryers currently use a non-isolated power supply to drive an external knob or button to control the working state. In the above design, when the user controls the working state of the air fryer through the touch screen, once a circuit fails or the user misoperates, it is easy to cause an electric shock accident, so there is a certain safety hazard.

[0046] In order to solve the above problems, the utility model proposes a control circuit and an air fryer, aiming to improve the safety of the air fryer.

[0047] See also Figure 1 In one embodiment of the utility model, the control circuit is applied to an air fryer, and the control circuit includes an isolation power supply circuit 10, a display control circuit 20 and a heating circuit 30.

[0048] In this embodiment, reference Figure 2 , the power input end of the isolated power supply circuit 10 is connected to the external AC power supply, and the external AC power supply is converted into a DC power supply through the isolated power supply, and the output is isolated, thereby providing a stable DC power supply for other circuits of the air fryer. In this embodiment, the external AC power supply can be AC220V / 50HZ or AC110V / 60HZ, which can be selected according to the actual application scenario. In this embodiment, the isolated power supply circuit 10 uses a transformer T3 to step down and electrically isolate the external AC power supply to ensure the safe operation of the circuit.

[0049] In another embodiment of the utility model, the isolated power supply circuit 10 includes a rectifier circuit 11, which is connected to an external AC power supply; the rectifier circuit 11 rectifies the external AC power supply into a DC power supply. In this embodiment, the rectifier circuit 11 includes a rectifier bridge U33, which rectifies the external AC power supply into a pulsating DC power supply. In this embodiment, the isolated power supply circuit also includes a first filter capacitor EC1 and a second filter capacitor EC2, and the first filter capacitor EC1 and the second filter capacitor EC2 are respectively electrically connected to the output end of the rectifier circuit 11, so as to filter the pulsating DC power supply and then convert it into a stable DC power supply. Further, the isolated power supply circuit 10 also includes a transformer circuit 12, and the transformer circuit 12 includes a transformer T3, and the primary coil of the transformer T3 is electrically connected to the rectifier circuit 11, and the transformer circuit 12 is used to step down the stable DC power supply after filtering by the first filter capacitor EC1 and the second filter capacitor EC2 to output a stable DC power supply of 5V. Through the cooperation of the rectifier circuit 11 and the transformer circuit 12 , the isolation and voltage-stabilized output of the external AC power supply are achieved, thereby providing a stable DC power supply for the display control circuit 20 .

[0050] In addition, in another embodiment of the utility model, in order to improve the stability of the circuit, the isolated power supply circuit 10 also includes a power supply protection circuit 13, the power supply protection circuit 13 is connected to the transformer circuit 12, and the power supply protection circuit 13 includes a power supply protection chip U32, the power supply protection chip U32 is used to control the output voltage of the isolated power supply and perform overcurrent protection, overvoltage protection, undervoltage protection and overtemperature protection on the DC power supply to ensure the safe operation of the circuit. When the current, voltage or temperature exceeds the preset safety range, the power supply protection chip U32 will promptly disconnect the current on the primary coil of the transformer T3 to prevent equipment damage or fire and other safety accidents.

[0051] Optionally, in one embodiment of the utility model, the transformer circuit 12 also includes a pulse protection circuit, which is connected in parallel with the primary coil of the transformer T3; the pulse protection circuit is used to absorb the high-voltage pulse generated by the transformer T3 when the power supply to the primary coil of the transformer T3 is disconnected.

[0052] In this embodiment, the pulse protection circuit includes a first resistor R40, a second resistor R71, a third resistor R41, a first capacitor C10 and a first diode D8; the first resistor R40 and the second resistor R71 are respectively connected in parallel with the primary coil of the transformer T3, and the third resistor R41, the first capacitor C10 and the first diode D8 are connected in series and connected in parallel with the transformer T3. When the power supply between the primary coil of the transformer T3 is disconnected, the pulse protection circuit can absorb the high-voltage pulse generated by the coil of the transformer T3, thereby effectively protecting the MOS tube inside the power chip and preventing it from being damaged by the high-voltage pulse, thereby improving the reliability and stability of the entire circuit.

[0053] Optionally, in another embodiment of the utility model, the isolated power supply circuit 10 further includes a fuse F1, which is arranged between the external AC power supply and the rectifier circuit 11. Through the fuse F1, the current can be automatically cut off when the circuit is overloaded or short-circuited to protect the safety of the circuit and the device. In this embodiment, a power protection circuit 13 is added to the isolated power supply circuit 10 to control the stable output of the 5V DC power supply, and the power supply is cut off when the power supply voltage is abnormal, thereby avoiding damage to the device due to voltage instability and ensuring the normal operation of the control circuit.

[0054] Optionally, in another embodiment of the utility model, the control circuit further includes a filter circuit, which is electrically connected to the output end of the isolation power supply circuit 10; the filter circuit is used to filter and output the power after being transformed by the transformer circuit 12.

[0055] In this embodiment, the filter circuit includes a second capacitor EC5, a third capacitor EC6 and a magnetic bead R79, the first ends of the second capacitor EC5, the third capacitor EC6 and the magnetic bead R79 are respectively electrically connected to the output end of the isolation power supply circuit 10, and the second ends of the second capacitor EC5, the third capacitor EC6 and the magnetic bead R79 are grounded. In this embodiment, the second capacitor, the third capacitor EC6 and the magnetic bead R79 constitute a π-type filter circuit, which can effectively reduce the ripple of the output power of the isolation power supply circuit.

[0056] Optionally, in another embodiment of the present invention, the isolated power supply circuit 10 also includes a power regulation circuit, which is electrically connected to the power supply protection circuit 13 and the transformer T3 respectively; the power regulation circuit is used to regulate the output power of the isolated power supply circuit 10.

[0057] In this embodiment, the power regulation circuit includes a fourth resistor R60 and a fifth resistor R61, the first end of the fourth resistor R60 is electrically connected to the transformer circuit 12, the second end of the fourth resistor R60 is connected to the first end of the fifth resistor R61, and the second end of the fifth resistor R61 is electrically connected to the power protection chip U32. In this embodiment, the power regulation circuit can adjust the output current of the isolated power supply circuit by changing the resistance value of the fourth resistor R60 and / or the fifth resistor R61, and then adjust the output power of the isolated power supply circuit 10 according to actual needs. At the same time, the power regulation circuit can also effectively protect the power supply circuit and equipment to prevent safety accidents caused by excessive or insufficient power.

[0058] In this embodiment, reference Figure 3 The display control circuit 20 is electrically connected to the isolated power supply circuit 10, and the isolated power supply circuit 10 provides a stable DC power supply for the display control circuit 20 to ensure the normal operation of the display control circuit 20. The display control circuit 20 includes a touch screen, and the user can control the working state of the air fryer through the touch screen, such as setting parameters such as cooking time and temperature, and starting, pausing, canceling, etc. The display control circuit 20 generates a corresponding heating control signal by receiving the user's operation instruction to control the working state of the heating circuit 30.

[0059] Optionally, in another embodiment of the present invention, the display control circuit 20 may include an MCU. Of course, the main control circuit 10 may also use a CPU, a DSP or other types of processing chips, which can receive and process operation instructions from the touch screen, as well as signals detected by various detection circuits, and generate corresponding control signals according to preset programs and algorithms to control the working state of the air fryer. In another embodiment of the present invention, the display control circuit 20 may also include a host computer, which may communicate with the air fryer through wireless communication methods such as Bluetooth, WIFI, infrared, or through a wired connection to receive and process operation instructions from the touch screen, as well as signals detected by various detection circuits, and generate corresponding control signals according to preset programs and algorithms to control the working state of the air fryer.

[0060] In this embodiment, the heating circuit 30 is electrically connected to the external AC power supply and the display control circuit 20 respectively; the control signal includes a heating control signal, and the heating circuit 30 is used to turn on or off the heating circuit of the air fryer by the external AC power supply according to the heating control signal.

[0061] In this embodiment, reference Figure 4The heating circuit 30 includes a relay K1 and an electric heating element. The input end of the relay K1 is connected to an external AC power source, the output end of the relay K1 is electrically connected to the electric heating element, and the controlled end of the heating circuit 30 is connected to the display control circuit 20. When the controlled end of the heating circuit 30 receives a heating control signal, the relay K1 is turned on, thereby turning on or off the heating circuit of the external AC power source to the air fryer, so that the electric heating element heats the air fryer.

[0062] In this embodiment, the isolation power supply circuit 10 converts the external AC power supply into a DC power supply, and isolates and outputs it to the display control circuit 20 to supply power to the display control current. The display control circuit 20 can output a heating control signal to the heating circuit 30, so that the heating circuit 30 can turn on or off the heating circuit of the air fryer by the external AC power supply according to the heating control signal. In this way, the display control circuit 20 is electrically isolated from the external AC power supply. When the user controls the working state of the air fryer through the touch screen, it can effectively prevent the circuit failure or misoperation from causing harm to the user, thereby improving the safety of the air fryer.

[0063] It is understandable that when the air fryer door is opened, in order to ensure safety, the heating circuit 30 is generally stopped to heat the air fryer. When a non-isolated power supply is used, stopping the heating will cause the entire system to lose power, thereby turning off the display screen. The display screen can only be lit again by restarting through an externally controlled knob or button, which seriously affects the user experience.

[0064] To solve the above problem, in one embodiment, the air fryer further includes an oven door, and the control circuit further includes an oven door detection circuit, which is electrically connected to the external AC power supply and the display control circuit 20. The oven door detection circuit is used to detect the switch state of the oven door, generate a corresponding oven door detection signal and output it to the display control circuit 20. The display control circuit 20 is also used to output a heating control signal to the heating circuit 30 when the oven door is in an open state, so as to disconnect the heating circuit of the air fryer from the external AC power supply.

[0065] Optional, reference Figure 5In one embodiment, the oven door detection circuit includes a first optocoupler chip U16, wherein a first input end of the first optocoupler chip U16 is connected to a live input end of an external AC power source, a second input end of the first optocoupler chip U16 is connected to a neutral input end of an external AC power source, a first output end of the first optocoupler chip U16 is electrically connected to the display control circuit 20, and a second output end of the first optocoupler chip U16 is grounded. In this way, the external AC power source is converted into a square wave signal that can be read by the display control circuit 20 through the first optocoupler chip U16, and the display control circuit 20 reads and processes the square wave signal to further determine the switch state of the oven door. When the oven door is in the open state, a heating control signal is output to the heating circuit 30 to disconnect the heating circuit of the air fryer from the external AC power source; at the same time, due to the disconnection of the heating circuit of the air fryer from the external AC power source, the zero-crossing detection signal of the oven door detection circuit disappears, and the touch screen can display a corresponding warning.

[0066] Optionally, in another embodiment of the utility model, relay K1 cooperates with the furnace door detection circuit to realize its state switching. The furnace door detection circuit detects the zero point of the voltage. When the controlled end of the heating circuit 30 receives the heating control signal, it ensures that relay K1 is turned on when the voltage is near 0V, thereby effectively protecting relay K1 and extending the service life of relay K1.

[0067] In this embodiment, through the oven door detection circuit, when the oven door is opened, the display control circuit 20 can automatically disconnect the heating circuit 30, thereby preventing the user from being harmed by the high temperature heat source when operating the oven door, and because the oven door detection circuit and the display control circuit 20 are also electrically isolated, the safety of the entire air fryer can be further improved. At the same time, when the oven door is opened, disconnecting the heating circuit 30 will not affect the normal operation of the display control circuit 20, that is, the touch screen can remain lit, and the user can continue to perform other operations through the touch screen without restarting the system, such as checking the cooking progress, setting new cooking parameters, etc., thereby improving the user experience.

[0068] Optional, reference Figure 6 In one embodiment, the control circuit further includes a temperature detection circuit, and the temperature detection circuit is electrically connected to the display control circuit 20. The temperature detection circuit is used to detect the temperature in the air fryer, generate a temperature detection signal, and output it to the display control circuit 20.

[0069] Optionally, in this embodiment, the air fryer further includes an NTC module, the temperature detection circuit includes a sixth resistor R48, and the temperature detection circuit is electrically connected to the NTC module. In this embodiment, the resistance value of the NTC module (negative temperature coefficient thermistor) decreases with increasing temperature, so by measuring the resistance value of the NTC module, the current temperature value can be accurately calculated.

[0070] In this embodiment, the voltage value of the NTC module is read by the sixth resistor R48 to calculate the resistance value of the NTC, and then the temperature value of the air fryer is obtained. In this embodiment, the temperature in the air fryer can be monitored in real time through the temperature detection circuit to ensure accurate temperature control during the cooking process. After receiving the temperature detection signal, the display control circuit 20 can adjust the heating circuit 30 accordingly according to the preset program and algorithm to maintain the set cooking temperature. In this way, not only the cooking efficiency and taste are improved, but also the safety problems caused by too high or too low temperature can be avoided.

[0071] refer to Figure 7 In one embodiment, the air fryer also includes a fan, the control circuit also includes a fan circuit, and the fan circuit is electrically connected to the display control circuit 20; the control signal also includes a fan control signal; the fan circuit is used to control the rotation speed of the fan according to the fan control signal.

[0072] In this embodiment, the fan circuit includes a first switch tube Q1 and a second optocoupler chip U1; the control circuit is connected to the controlled end of the first switch tube Q1, the first end of the first switch tube Q1 is electrically connected to the second optocoupler chip U1, and the second end of the second switch tube Q6 is grounded. In this embodiment, when the display control circuit 20 outputs a fan control signal to the controlled end of the first switch tube Q1, the conduction state of the first switch tube Q1 can be controlled, and the conduction state of the second optocoupler chip U1 can be controlled, thereby controlling the speed of the fan.

[0073] In this embodiment, through the fan circuit, the rotation speed of the fan can be accurately controlled according to the needs of cooking to achieve better cooking effects. For example, at different stages of cooking, different wind speeds may be required or the fan may be turned off in time to cooperate with the heating element to achieve effects such as uniform heating and flipping ingredients. The display control circuit 20 can control the fan circuit by outputting a fan control signal, thereby adjusting the rotation speed of the fan to meet cooking needs. In addition, the fan circuit in this embodiment also uses an optocoupler chip for electrical isolation, which effectively improves the safety of the entire air fryer. Even in the event of a circuit failure or misoperation, it can effectively prevent harm to the user.

[0074] In one embodiment, the air fryer also includes an oven lamp, the control circuit also includes an oven lamp circuit, and the oven lamp circuit is electrically connected to the display control circuit 20; the control signal also includes an oven lamp control signal; the oven lamp circuit is used to control the brightness of the oven lamp according to the oven lamp control signal.

[0075] In this embodiment, the furnace lamp circuit includes a second switch tube Q6 and a third optocoupler chip U34; the control circuit is connected to the controlled end of the second switch tube Q6, the first end of the second switch tube Q6 is electrically connected to the third optocoupler chip U34, and the second end of the second switch tube Q6 is electrically connected to the furnace lamp. When the display control circuit 20 outputs a furnace lamp control signal to the controlled end of the second switch tube Q6, the conduction state of the second switch tube Q6 can be controlled, and then the conduction state of the third optocoupler chip U34 can be controlled, thereby controlling the brightness of the furnace lamp.

[0076] In this embodiment, through the oven light circuit, the brightness of the oven light or its on or off can be accurately controlled according to the needs of cooking. In addition, the oven light circuit in this embodiment also uses an optocoupler chip for electrical isolation, which improves the safety of the entire air fryer.

[0077] In one embodiment, the control circuit further includes a buzzer circuit, and the buzzer circuit is electrically connected to the display control circuit 20; the control signal further includes a buzzer control signal; and the buzzer circuit is used to issue a sound prompt according to the buzzer control signal.

[0078] Optionally, in this embodiment, the buzzer circuit includes a buzzer U15. As an optional solution but not a limitation, the buzzer U15 is a piezoelectric buzzer, which can have no obvious sound changes under an environment of 80°C. In this embodiment, through the buzzer circuit, a sound prompt is issued under specific circumstances, such as when the oven door is opened, cooking is completed, or a fault occurs. The display control circuit 20 can control the switch of the buzzer circuit by outputting a buzzer control signal, thereby issuing a corresponding sound prompt, so that the user can promptly understand the working status of the air fryer or receive warning information.

[0079] In this embodiment, the external AC power supply is converted into a DC power supply through the isolation power supply circuit 10, and the DC power supply is isolated and output to the display control circuit 20 to supply power to the display control circuit. The display control circuit 20 can output a heating control signal to the heating circuit 30, so that the heating circuit 30 can turn on or off the heating circuit of the air fryer by the external AC power supply according to the heating control signal. In this way, the display control circuit 20 is electrically isolated from the external AC power supply. When the user controls the working state of the air fryer through the touch display screen, it can effectively prevent the circuit failure or misoperation from causing harm to the user, thereby improving the safety of the air fryer.

[0080] The utility model also proposes an air fryer, which includes the control circuit. The specific structure of the control circuit refers to the above embodiment. Since the air fryer adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0081] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A control circuit, applied to an air fryer, characterized in that: The control circuit comprises: An isolated power supply circuit; the isolated power supply circuit is used to convert an external AC power supply into a DC power supply and isolate the output; A display control circuit, comprising a touch display screen, the display control circuit being electrically connected to the isolated power supply circuit; the display control circuit being used to display the working state of the air fryer and output a control signal to control the working state of the air fryer; A heating circuit, the heating circuit being electrically connected to the external AC power supply and the display control circuit respectively; the control signal comprises a heating control signal, and the heating circuit is used to turn on or off the heating circuit of the air fryer by the external AC power supply according to the heating control signal; A filter circuit is electrically connected to the isolation power supply circuit.

2. The control circuit according to claim 1, characterized in that: The air fryer further includes a furnace door, and the control circuit further includes: An oven door detection circuit, the oven door detection circuit being electrically connected to the external AC power supply and the display control circuit respectively; the oven door detection circuit is used to detect the switch state of the oven door, generate a corresponding oven door detection signal and output it to the display control circuit; The display control circuit is also used to output a heating control signal to the heating circuit when the oven door is in an open state, so as to disconnect the heating circuit of the air fryer from the external AC power supply.

3. The control circuit according to claim 1, characterized in that: The isolated power supply circuit comprises: A rectifier circuit, the rectifier circuit is connected to an external AC power source; the rectifier circuit is used to rectify the external AC power source into a DC power source; A transformer circuit, the transformer circuit is connected to the rectifier circuit; the transformer circuit is used to isolate and output the DC power supply.

4. The control circuit according to claim 3, characterized in that: The voltage conversion circuit includes a transformer; The isolated power supply circuit also includes a power supply protection circuit, and the power supply protection circuit is electrically connected to the transformer.

5. The control circuit according to claim 4, characterized in that: The voltage conversion circuit also includes a pulse protection circuit, which is connected in parallel with the primary coil of the transformer; the pulse protection circuit is used to absorb the high-voltage pulse generated by the transformer when the power supply to the primary coil of the transformer is disconnected.

6. The control circuit according to claim 5, characterized in that: The isolated power supply circuit also includes a power regulation circuit, which is electrically connected to the power supply protection circuit and the transformer respectively; the power regulation circuit is used to regulate the output power of the isolated power supply circuit.

7. The control circuit according to claim 1, characterized in that: The control circuit also includes a temperature detection circuit, which is electrically connected to the display control circuit; the temperature detection circuit is used to detect the temperature inside the air fryer, generate a temperature detection signal, and output it to the display control circuit.

8. The control circuit according to claim 1, characterized in that: The air fryer also includes a fan and a furnace lamp, and the control circuit also includes: A fan circuit, the fan circuit being electrically connected to the display control circuit; the control signal further comprising a fan control signal; the fan circuit being used to control the rotation speed of the fan according to the fan control signal; and / or, A furnace lamp circuit, the furnace lamp circuit is electrically connected to the display control circuit; the control signal also includes a furnace lamp control signal; the furnace lamp circuit is used to control the brightness of the furnace lamp according to the furnace lamp control signal.

9. The control circuit according to claim 1, characterized in that: The control circuit further comprises: A buzzer circuit is electrically connected to the display control circuit; the control signal also includes a buzzer control signal; the buzzer circuit is used to issue a sound prompt according to the buzzer control signal.

10. An air fryer, characterized in that: The air fryer comprises a control circuit as claimed in any one of claims 1 to 9.

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