A dual-sensor-based anti-dry-burning control device

Abstract

This utility model provides a dual-sensor anti-dry-burning control device, relating to the fields of electronic circuits and medical devices. It includes: an anti-dry-burning control circuit, a water level sensor, an NTC sensor, and an LCD. The water level sensor specifically includes a capacitive liquid level probe and an infrared optical liquid level probe; the water level sensor is used to detect changes in liquid level. The anti-dry-burning control circuit specifically includes: a main control chip, a step-down circuit, a fan drive circuit, an atomization drive circuit, a heating drive circuit, a buzzer drive circuit, and a level conversion circuit. The step-down circuit, fan drive circuit, atomization drive circuit, heating drive circuit, buzzer drive circuit, and level conversion circuit are all connected to the main control chip, which is used to control the on / off state of the anti-dry-burning control circuit. Both the water level sensor and the NTC sensor are connected to the main control chip.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuits and medical device technology, and in particular to an anti-dry-burning control device based on dual sensors. Background Technology

[0002] A dual-sensor anti-dry-burning control device refers to a control system in equipment involving liquids, such as heating or atomization, that uses real-time detection of liquid level or temperature to achieve mutual complementarity and cross-verification. This ensures that the equipment can take timely protective measures such as power-off and alarm in the event of liquid shortage or overheating, thus preventing dry-burning.

[0003] If devices such as atomizers and heaters continue to operate without liquid, it is very easy to cause overheating, damage, or even safety accidents. Therefore, there is a need for an anti-dry-burning control device that can significantly improve the accuracy of liquid level detection, thereby providing a safer and more stable guarantee for use in fields such as medical care and home appliances.

[0004] However, in existing medical nebulizers, the anti-dry-burn function mostly relies on a single liquid level sensor to detect the remaining medication. When the sensor misjudges due to poor water quality, medication adhesion, air bubble interference, or device aging, the nebulizer may continue to work without water, causing the nebulizer plate to burn out. This not only shortens the lifespan of the device but may also pose a safety hazard. At the same time, although some devices use temperature sensors for protection, the response is delayed, and the sensor only activates when the nebulizer plate has already overheated, resulting in limited protection and failing to achieve timely and reliable prevention of dry burning. Utility Model Content

[0005] In view of the shortcomings of the prior art, the purpose of this utility model embodiment is to provide a dual-sensor anti-dry-burn control device, which can solve the problem that in existing medical nebulizers, the anti-dry-burn function mostly relies on a single liquid level sensor to detect the remaining liquid. When the sensor misjudges due to poor water quality, liquid adhesion, bubble interference, or device aging, the nebulizer may continue to work in a waterless state, causing the nebulizer plate to dry-burn. This not only shortens the life of the device but may also cause safety hazards. At the same time, although some devices use temperature sensors for protection, due to the lag in response, they only activate when the nebulizer plate has already overheated, resulting in limited protection and failing to achieve timely and reliable prevention of dry burning.

[0006] This utility model embodiment proposes a dual-sensor anti-dry-burning control device, including: an anti-dry-burning control circuit, a water level sensor, an NTC sensor, and an LCD;

[0007] The water level sensor specifically includes: a capacitive liquid level probe and an infrared optical liquid level probe;

[0008] The water level sensor is used to detect changes in liquid level;

[0009] The anti-dry-burning control circuit specifically includes: a main control chip, a step-down circuit, a fan drive circuit, an atomization drive circuit, a heating drive circuit, a buzzer drive circuit, and a level conversion circuit;

[0010] The step-down circuit, the fan drive circuit, the atomization drive circuit, the heating drive circuit, the buzzer drive circuit, and the level conversion circuit are all connected to the main control chip, which is used to control the on / off state of the anti-dry burning control circuit.

[0011] Both the water level sensor and the NTC sensor are connected to the main control chip;

[0012] The LCD is connected to the main control chip through the level conversion circuit;

[0013] When both the capacitive liquid level probe and the infrared optical liquid level probe detect water, the main control chip controls the switch to turn on, supplying power to the anti-dry burning control circuit for atomization.

[0014] When the capacitive liquid level probe or the infrared optical liquid level probe detects a waterless state, the main control chip controls the switch tube to turn off, cuts off the power supply to the anti-dry burning control circuit, stops atomization, and issues a warning through an audible and visual alarm.

[0015] The beneficial effects of the technical solution provided by this utility model embodiment include at least the following:

[0016] In this embodiment of the invention, a dual-sensor detection method using a capacitive liquid level probe and an infrared optical liquid level probe is adopted, achieving dual verification of liquid level information. This effectively avoids misjudgments caused by a single sensor due to water quality, air bubbles, or drug adhesion, thereby significantly improving the accuracy and reliability of anti-dry burning detection. Through the centralized control of the main control chip over the step-down circuit, fan drive circuit, atomization drive circuit, heating drive circuit, buzzer drive circuit, and level conversion circuit, the power supply can be cut off in time when the liquid level is insufficient to prevent the atomizing plate from dry burning. By setting an NTC sensor, real-time monitoring and over-temperature protection of the atomizing plate temperature are achieved, further improving system safety. The LCD provides an intuitive display of the working status and alarm information, allowing users to keep abreast of the equipment's operating status. Overall, the safety, stability, and user experience of the device are improved. Attached Figure Description

[0017] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this invention. Throughout the drawings, the same reference numerals denote the same components. Obviously, the drawings described below are merely some embodiments of this invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a dual-sensor anti-dry-burning control device provided in an embodiment of this utility model.

[0019] Figure 2 This is a schematic diagram of the structure of a 78M12 circuit provided in an embodiment of this utility model.

[0020] Figure 3 This is a schematic diagram of the structure of an AMS1117-3.3 circuit provided in an embodiment of this utility model.

[0021] Figure 4 This is a schematic diagram of the structure of an atomization driving circuit provided in an embodiment of this utility model.

[0022] Figure 5 This is a schematic diagram of the control circuit of a main control chip provided in an embodiment of the present invention.

[0023] Figure 6 This is a schematic diagram of the structure of a liquid level detection circuit provided in an embodiment of the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions in the embodiments of this utility model, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. It should be understood that these descriptions are exemplary only and are not intended to limit the scope of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0025] Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts disclosed in this utility model.

[0026] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this invention.

[0027] Reference manual attached Figures 1 to 6 The present invention provides a structure for a dual-sensor anti-dry-burning control device, comprising: an anti-dry-burning control circuit, a water level sensor, an NTC sensor, and an LCD.

[0028] Water level sensors specifically include: capacitive liquid level probes and infrared optical liquid level probes.

[0029] Water level sensors are used to detect changes in liquid level.

[0030] The anti-dry-burning control circuit specifically includes: a main control chip, a step-down circuit, a fan drive circuit, an atomization drive circuit, a heating drive circuit, a buzzer drive circuit, and a level conversion circuit.

[0031] The step-down circuit, fan drive circuit, atomization drive circuit, heating drive circuit, buzzer drive circuit, and level conversion circuit are all connected to the main control chip, which is used to control the on / off state of the anti-dry-burning control circuit.

[0032] Both the water level sensor and the NTC sensor are connected to the main control chip.

[0033] The LCD is connected to the main control chip via a level conversion circuit.

[0034] When both the capacitive liquid level probe and the infrared optical liquid level probe detect water, the main control chip controls the switching transistor to turn on, supplying power to the anti-dry-burning control circuit for atomization.

[0035] When the capacitive liquid level probe or the infrared optical liquid level probe detects a waterless state, the main control chip controls the switch tube to turn off, cuts off the power supply to the anti-dry burning control circuit, stops atomization, and issues a warning through an audible and visual alarm.

[0036] The beneficial effects of the technical solution provided by this utility model embodiment include at least the following:

[0037] In this embodiment of the invention, a dual-sensor detection method using a capacitive liquid level probe and an infrared optical liquid level probe is adopted, achieving dual verification of liquid level information. This effectively avoids misjudgments caused by a single sensor due to water quality, air bubbles, or drug adhesion, thereby significantly improving the accuracy and reliability of anti-dry burning detection. Through the centralized control of the main control chip over the step-down circuit, fan drive circuit, atomization drive circuit, heating drive circuit, buzzer drive circuit, and level conversion circuit, the power supply can be cut off in time when the liquid level is insufficient to prevent the atomizing plate from dry burning. By setting an NTC sensor, real-time monitoring and over-temperature protection of the atomizing plate temperature are achieved, further improving system safety. The LCD provides an intuitive display of the working status and alarm information, allowing users to keep abreast of the equipment's operating status. Overall, the safety, stability, and user experience of the device are improved.

[0038] In one possible implementation, the step-down circuit specifically includes a 78M12 circuit and an AMS1117-3.3 circuit.

[0039] The 78M12 circuit is used to step down a 24V voltage to a 12V voltage.

[0040] The AMS1117-3.3 circuit is used to step down a 12V voltage to a 3.3V voltage.

[0041] It should be noted that by stepping the 24V voltage down to 12V via a 78M12 circuit and then regulating it to 3.3V via an AMS1117-3.3 circuit, not only is a stable power supply to the main control chip and logic circuit achieved, but the chip damage and system instability that may be caused by direct high voltage power supply are also effectively avoided, thus improving the overall reliability and safety of the circuit.

[0042] In one possible implementation, the 78M12 circuit specifically includes: connector CN5, capacitors C18, C17, C8, and C10, resistors R8, R9, R10, R11, and R12, inductor L2, common-mode inductor U3, three-terminal voltage regulator chip U33, VCC_24V node, and VCC_12V node.

[0043] Pin 2 of connector CN5 is connected to the VCC_24V node to receive 24V voltage.

[0044] Pin 1 of connector CN5 is grounded.

[0045] One end of capacitor C18 is grounded, and the other end is connected to pin 2 of connector CN5.

[0046] Pins 1 and 2 of the common mode inductor U3 form a winding. Pin 2 is connected to one end of resistor R9, and the other end of resistor R9 is grounded.

[0047] Pins 3 and 4 of the common-mode inductor U3 form another set of windings. Pin 3 is connected to one end of resistor R8, and the other end of resistor R8 is connected to pin 4.

[0048] Pin 4 of the common-mode inductor U3 is used to output 24V voltage.

[0049] After capacitors C17 and C8 are connected in parallel, one end is connected to the VCC_24V node, and the other end is grounded.

[0050] One end of inductor L2 is connected to the VCC_24V node, and the other end is grounded.

[0051] Capacitors C17 and C8, together with inductor L2, form a power supply filter network used for filtering and buffering the 24V DC power supply.

[0052] The VCC_24V node is connected to one end of inductor L2, and the other end of inductor L2 is grounded.

[0053] After resistors R10, R11, and R12 are connected in parallel, one end is connected to the VCC_24V node, and the other end is connected to the IN pin of the three-terminal voltage regulator chip U33.

[0054] The GND pin of the three-terminal voltage regulator chip U33 is grounded, and the OUT pin is connected to one end of capacitor C10, while the other end of capacitor C10 is grounded.

[0055] The OUT pin of the three-terminal voltage regulator chip U33 is connected to the VCC_12V node, and the OUT pin is used to output the regulated 12V voltage.

[0056] It should be noted that the input filter capacitor, common-mode inductor, and parallel resistor network in the 78M12 circuit can not only effectively suppress input ripple and electromagnetic interference, but also provide stable power supply buffer. Combined with the three-terminal voltage regulator chip U33, it can achieve a regulated output from 24V to 12V, thereby ensuring the power supply stability of the subsequent circuits and the reliability of the system operation.

[0057] In one possible implementation, the AMS1117-3.3 circuit specifically includes: inductor L13, capacitors C53, C54, C58, C51, C55, and C59, a three-terminal voltage regulator chip U1, a ferrite bead L15, an LED1, a resistor R84, a VCC_12V node, and a VCC_3V3 node.

[0058] One end of capacitor C53 is connected to the VCC_12V node, and the other end of capacitor C53 is grounded.

[0059] The input terminal of inductor L13 is connected to the VCC_12V node. The output terminal of inductor L13 is connected to one end of capacitors C54, C58, and C51. The other ends of capacitors C54, C58, and C51 are all grounded.

[0060] The output terminal of inductor L13 is connected to the VIN pin of three-terminal voltage regulator chip U1.

[0061] The GND pin of the three-terminal voltage regulator chip U1 is grounded, and the VOUT pin outputs a voltage of 3.3V.

[0062] The VOUT pin of the three-terminal voltage regulator chip U1 is connected to one end of both capacitor C55 and capacitor C59, while the other end of capacitors C55 and C59 is grounded.

[0063] The VOUT pin of the three-terminal voltage regulator chip U1 is connected to the ferrite bead L15, and the other end of the ferrite bead L15 is connected to the VCC_3V3 node.

[0064] The VCC_3V3 node is connected to the anode of LED1, and the cathode of LED1 is connected to one end of resistor R84. The other end of resistor R84 is grounded.

[0065] It should be noted that the AMS1117-3.3 circuit regulates the 12V voltage to 3.3V and combines a multi-stage noise suppression design with input inductors, capacitors for filtering and output ferrite beads. This not only effectively reduces high-frequency interference and ensures a clean and stable voltage output, but also provides a safe and reliable low-voltage power supply for the main control chip and logic circuits. At the same time, the power status is visualized using LED indicators, which improves the maintainability and reliability of the circuit.

[0066] In one possible implementation, the atomization driving circuit specifically includes: resistors R1, R2, R3, R4, R13, R14, R15, and R99; capacitors C11, C12, C13, C14, C15, and C68; inductor L1; diodes D1 and D2; MOSFET Q3; driving chip U35; interface CN1; and VCC_24V node.

[0067] Resistor R1, resistor R2, and capacitor C12 are connected in parallel and then connected to the VCC_24V node and the input terminal of diode D1, respectively.

[0068] One end of inductor L1 is connected to the VCC_24V node, and the other end of inductor L1 is grounded.

[0069] The output terminal of diode D1 is connected to one end of capacitor C13 and capacitor C15, and the other end of capacitor C13 and capacitor C15 is grounded.

[0070] The source of MOSFET Q3 is grounded.

[0071] The drain of MOSFET Q3 is connected to the output terminal of diode D1. The drain of MOSFET Q3 is connected to one end of capacitors C13 and C15. The drain of MOSFET Q3 is connected to one end of capacitor C14 and pin 2 of interface CN1. The other end of capacitor C14 is grounded. Pin 1 of interface CN1 is grounded.

[0072] The source of MOSFET Q3 is grounded, and the drain of MOSFET Q3 is connected to the output terminal of diode D1.

[0073] The gate of MOSFET Q3 is grounded through resistor R3. The gate of MOSFET Q3 is connected to the parallel branch of resistor R4 and diode D2. The gate of MOSFET Q3 is connected to one end of resistor R99. The other end of resistor R99 is connected to one end of capacitor R68. The other end of capacitor R68 is grounded.

[0074] The VDD pin of the driver chip U35 is connected to the VCC_12V node, the GND pin of the driver chip U35 is grounded, the IN pin of the driver chip U35 receives the PWM signal from the MCU, and the OUT pin of the driver chip U35 is connected to the parallel branch of resistor R4 and diode D2.

[0075] Resistors R14 and R13 are connected in parallel and then connected to pin 1 of interface CN1 and ground, respectively.

[0076] Pin 1 of interface CN1 is connected to one end of resistor R15, the other end of resistor R15 is connected to one end of capacitor C11, and the other end of capacitor C11 is grounded.

[0077] It should be noted that the atomization drive circuit uses the driver chip U35 and the MOSFET Q3 in conjunction with a filtering and protection network composed of resistors, capacitors, inductors and diodes. This not only effectively amplifies the PWM signal output by the MCU into a high-frequency, high-power drive signal to achieve stable driving of the atomizing plate, but also suppresses interference and avoids damage to the devices caused by overcurrent and overvoltage in the circuit, thereby improving atomization efficiency and system safety and reliability.

[0078] In one possible implementation, the control circuit of the main control chip specifically includes: main control chip U23, capacitors C36, C37, C38, C43, C44, C45, C48, C56, C57, resistors R39, R68, R83, R94, LED5, inductor L11, crystal X3, debugging interface H2, and VCC_3V3 node.

[0079] The VDD pin of the main control chip U23 is connected to the VCC_3V3 node, the VSS pin of the main control chip U23 is grounded, and capacitors C37, C38, C48 and C56 are connected in parallel between the VDD pin and the VSS pin of the main control chip U23. The other ends of capacitors C37, C38, C48 and C56 are all grounded.

[0080] One end of the NRST pin of the main control chip U23 is connected to resistor R39 and capacitor C36. The other end of resistor R39 is connected to the VCC_3V3 node, and the other end of capacitor C36 is grounded, forming a reset circuit.

[0081] Crystal X3, capacitor C43, and capacitor C44 constitute a clock circuit. The two ends of crystal X3 are connected to the OSC_IN pin and OSC_OUT pin of the main control chip U23, respectively. One end of capacitors C43 and C44 are connected to the OSC_IN pin and OSC_OUT pin, respectively, and the other ends are grounded.

[0082] One end of inductor L11 is connected to the VCC_3V3 node, and the other end is connected to the VDDA pin of the main control chip U23. Capacitors C37 and C38 are connected in parallel between the VDDA pin and ground.

[0083] The anode of LED5 is connected to resistor R68, and the other end of resistor R68 is connected to the VCC_3V3 node. The cathode of LED5 is connected to the IO_RED pin of the main control chip U23.

[0084] The debugging interfaces SWDIO, SWCLK, and NRST of the main control chip U23 are connected to the corresponding pins of the debugging interface H2. The power supply pin of the debugging interface H2 is connected to the VCC_3V3 node, and the ground pin of the debugging interface H2 is grounded.

[0085] One end of capacitors C45 and C57 connected in parallel is connected to the main control chip U23, and the other end is grounded.

[0086] One end of resistor R83 is connected to the VCC_3V3 node, and the other end of resistor R83 is connected to the BOOT0 pin of the main control chip U23.

[0087] One end of resistor R94 is connected to the VOICE pin of the main control chip U23, and the other end is grounded.

[0088] It should be noted that by setting power decoupling capacitors, reset circuits, clock circuits, BOOT0 pull-up resistors, and debugging interfaces in the main control chip's control circuit, not only can the power supply stability and reliable startup of the main control chip be guaranteed during power-on and operation, but it can also provide a precise clock source and flexible program download function. At the same time, the operation status can be visualized with status indicator lights, thereby significantly improving the system's stability, maintainability, and overall reliability.

[0089] In this embodiment of the invention, the main control chip uses two ADCs to monitor the atomization power and NTC input respectively. The atomizing plate, fan, and heating tube are controlled by PWM. Connector H2 is connected to the programmer. The specific pin assignment is as follows:

[0090] 1. Microcontroller Core

[0091] Chip: STM32F030C8T6TR

[0092] The chip is the brain of the entire circuit, and all peripheral circuits serve it.

[0093] The package is LQFP-48, with 48 pins, providing multiple GPIOs, communication interfaces (USART, I2C, SPI, etc.), timers, and ADC resources.

[0094] 2. Power supply circuit

[0095] This is the cornerstone of ensuring stable MCU operation. From Figure 4 As can be seen in:

[0096] Power input: Figure 4 The inclusion of VCC_3V3 indicates that the system operates at 3.3V.

[0097] Decoupling capacitors: These are the most numerous components in the diagram (such as C36, C45, C57, C66, C37, C38, etc., with capacitance values ​​mostly around 100nF).

[0098] Filtering: Filtering out high-frequency noise on the power line.

[0099] Energy storage: Provides a local energy source for the MCU's instantaneous high current demand and stabilizes the voltage near the chip.

[0100] Design features: Typically, a 100nF ceramic capacitor is placed close to each power supply pin (VDD) and ground (VSS) of the MCU. This design is good engineering practice.

[0101] Power indicator: This may be indicated by an LED (such as LED5) and a current-limiting resistor to show whether the power is on properly.

[0102] 3. Reset circuit

[0103] Components: A typical power-on reset circuit is formed by resistor R39 (10kΩ) and capacitor C96 (100nF) and connected to the NRST pin of the MCU.

[0104] Upon power-up, capacitor C96 is essentially short-circuited, the NRST pin is pulled low, triggering an MCU reset.

[0105] The capacitor then charges through resistor R39, and the voltage gradually increases. Once it reaches a certain level, the MCU ends the reset state and begins operation.

[0106] Resistor R39 also provides a discharge circuit for the manual reset button (not explicitly shown in the diagram, but often reserved).

[0107] Function: To ensure that the MCU starts executing the program from a known initial state after the power supply is stable.

[0108] 4. Clock circuit

[0109] MCUs require a clock signal to synchronize all internal operations. This invention uses an internal clock: the STM32 also has a built-in RC oscillator, allowing it to operate without an external crystal oscillator.

[0110] 5. Program download and debugging interface

[0111] Interface: The diagram clearly marks the "programming port," which is a standard SWD interface.

[0112] SWD: It is the recommended 2-wire debug download interface for ARM Cortex-M core chips, which uses fewer pins than the traditional JTAG interface.

[0113] It mainly consists of two signal lines: SWDIO (data line) and SWCLK (clock line).

[0114] It also includes VCC (power supply), GND (ground) and an optional RESET line.

[0115] Function: Through this interface, engineers can use debuggers such as ST-Link and J-Link to burn the compiled program into the MCU's Flash memory and perform online debugging.

[0116] In one possible implementation, the water level sensor has a built-in liquid level detection circuit.

[0117] The liquid level detection circuit includes: a capacitive liquid level detection circuit and an infrared optical liquid level detection circuit.

[0118] The capacitive liquid level detection circuit specifically includes: capacitor C66, connector CN4, and signal line LIQD_DETECT2.

[0119] One end of capacitor C66 is connected to the signal line LIQD_DETECT2, and the other end is grounded.

[0120] Pin 3 of connector CN3 is connected to the VCC_3V3 node, pin 2 of connector CN3 is connected to the signal line LIQD_DETECT2, and pin 1 of connector CN3 is grounded.

[0121] The infrared optical liquid level detection circuit specifically includes: resistor R97, capacitor C65, connector CN3, signal line LIQD_DETECT, and VCC_3V3 node.

[0122] One end of resistor R97 is connected to the VCC_3V3 node, and the other end of resistor R97 is connected to one end of capacitor C65. The other end of capacitor C65 is connected to the signal line LIQD_DETECT. The signal line LIQD_DETECT is connected to pin 2 of connector CN3, and pin 1 of connector CN3 is grounded.

[0123] It should be noted that by incorporating a capacitive liquid level detection circuit and an infrared optical liquid level detection circuit into the water level sensor, and utilizing a dual detection mechanism to achieve cross-verification of the liquid level signal, not only can the misjudgment caused by a single sensor due to bubbles, water quality, or drug adhesion be effectively avoided, but the accuracy and reliability of water shortage detection can also be significantly improved. This ensures that the atomizer can stop in time and issue an alarm when there is no water, thereby improving the overall safety and stability of the system.

[0124] This utility model encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this utility model. To provide the public with a thorough understanding of this utility model, specific details are described in detail in the preferred embodiments; however, those skilled in the art can fully understand this utility model without these details. Furthermore, to avoid unnecessary confusion regarding the essence of this utility model, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model, and not to limit it. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present utility model. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A dual sensor based dry run prevention control device, characterized in that, include: Anti-dry-burning control circuit, water level sensor, NTC sensor, and LCD; The water level sensor specifically includes: a capacitive liquid level probe and an infrared optical liquid level probe; The water level sensor is used to detect changes in liquid level; The anti-dry-burning control circuit specifically includes: a main control chip, a step-down circuit, a fan drive circuit, an atomization drive circuit, a heating drive circuit, a buzzer drive circuit, and a level conversion circuit; The step-down circuit, the fan drive circuit, the atomization drive circuit, the heating drive circuit, the buzzer drive circuit, and the level conversion circuit are all connected to the main control chip, which is used to control the on / off state of the anti-dry burning control circuit. Both the water level sensor and the NTC sensor are connected to the main control chip; The LCD is connected to the main control chip through the level conversion circuit; When both the capacitive liquid level probe and the infrared optical liquid level probe detect water, the main control chip controls the switch to turn on, supplying power to the anti-dry burning control circuit for atomization. When the capacitive liquid level probe or the infrared optical liquid level probe detects a waterless state, the main control chip controls the switching transistor to turn off, cuts off the power supply to the anti-dry burning control circuit, stops atomization, and issues a warning.

2. The dual sensor based anti dry out control device as claimed in claim 1 wherein, The step-down circuit specifically includes: a 78M12 circuit and an AMS1117-3.3 circuit; The 78M12 circuit is used to step down the 24V voltage to 12V voltage; The AMS1117-3.3 circuit is used to step down the 12V voltage to 3.3V.

3. The dual sensor based anti dry out control device as claimed in claim 2 wherein, The 78M12 circuit specifically includes: connector CN5, capacitors C18, C17, C8, and C10, resistors R8, R9, R10, R11, and R12, inductor L2, common-mode inductor U3, three-terminal voltage regulator chip U33, VCC_24V node, and VCC_12V node. Pin 2 of connector CN5 is connected to the VCC_24V node to receive 24V voltage; Pin 1 of connector CN5 is grounded; One end of the capacitor C18 is grounded, and the other end is connected to pin 2 of the connector CN5; Pin 1 and pin 2 of the common mode inductor U3 form a winding, pin 2 is connected to one end of the resistor R9, and the other end of the resistor R9 is grounded; Pins 3 and 4 of the common mode inductor U3 form another set of windings. Pin 3 is connected to one end of resistor R8, and the other end of resistor R8 is connected to pin 4. Pin 4 of the common-mode inductor U3 is used to output 24V voltage; After capacitors C17 and C8 are connected in parallel, one end is connected to the VCC_24V node, and the other end is grounded. One end of the inductor L2 is connected to the VCC_24V node, and the other end is grounded; The capacitors C17 and C8 together with the inductor L2 form a power supply filtering network for filtering and buffering the DC 24V power supply. The VCC_24V node is connected to one end of inductor L2, and the other end of inductor L2 is grounded. After resistors R10, R11, and R12 are connected in parallel, one end is connected to the VCC_24V node, and the other end is connected to the IN pin of the three-terminal voltage regulator chip U33. The GND pin of the three-terminal voltage regulator chip U33 is grounded, the OUT pin is connected to one end of the capacitor C10, and the other end of the capacitor C10 is grounded. The OUT pin of the three-terminal voltage regulator chip U33 is connected to the VCC_12V node, and the OUT pin is used to output the regulated 12V voltage.

4. The dual sensor based anti dry out control device as claimed in claim 2 wherein, The AMS1117-3.3 circuit specifically includes: inductor L13, capacitors C53, C54, C58, C51, C55, and C59, a three-terminal voltage regulator chip U1, a ferrite bead L15, an LED1, a resistor R84, a VCC_12V node, and a VCC_3V3 node. One end of capacitor C53 is connected to the VCC_12V node, and the other end of capacitor C53 is grounded. The input terminal of the inductor L13 is connected to the VCC_12V node, and the output terminal of the inductor L13 is simultaneously connected to one end of the capacitors C54, C58, and C51. The other ends of the capacitors C54, C58, and C51 are all grounded. The output terminal of the inductor L13 is connected to the VIN pin of the three-terminal voltage regulator chip U1; The GND pin of the three-terminal voltage regulator chip U1 is grounded, and the VOUT pin outputs a voltage of 3.3V. The VOUT pin of the three-terminal voltage regulator chip U1 is connected to one end of both capacitor C55 and capacitor C59, and the other end of capacitor C55 and capacitor C59 is grounded. The VOUT pin of the three-terminal voltage regulator chip U1 is connected to the magnetic bead L15, and the other end of the magnetic bead L15 is connected to the VCC_3V3 node; The VCC_3V3 node is connected to the anode of the LED1, the cathode of the LED1 is connected to one end of the resistor R84, and the other end of the resistor R84 is grounded.

5. The dual sensor based anti dry out control device as claimed in claim 1 wherein, The atomization driving circuit specifically includes: resistors R1, R2, R3, R4, R13, R14, R15, R99, capacitors C11, C12, C13, C14, C15, and C68, inductor L1, diodes D1 and D2, MOSFET Q3, driver chip U35, interface CN1, and VCC_24V node; The resistor R1, the resistor R2, and the capacitor C12 are connected in parallel and then connected to the VCC_24V node and the input terminal of the diode D1, respectively. One end of the inductor L1 is connected to the VCC_24V node, and the other end of the inductor L1 is grounded; The output terminal of the diode D1 is connected to one end of the capacitors C13 and C15, and the other end of the capacitors C13 and C15 is grounded. The source of the MOS transistor Q3 is grounded; The drain of the MOSFET Q3 is connected to the output terminal of the diode D1. The drain of the MOSFET Q3 is connected to one end of the capacitor C13 and one end of the capacitor C15. The drain of the MOSFET Q3 is connected to one end of the capacitor C14 and pin 2 of the interface CN1. The other end of the capacitor C14 is grounded. Pin 1 of the interface CN1 is grounded. The source of the MOSFET Q3 is grounded, and the drain of the MOSFET Q3 is connected to the output terminal of the diode D1. The gate of the MOS transistor Q3 is grounded through the resistor R3. The gate of the MOS transistor Q3 is connected to the parallel branch of the resistor R4 and the diode D2. The gate of the MOS transistor Q3 is connected to one end of the resistor R99. The other end of the resistor R99 is connected to one end of the capacitor R68. The other end of the capacitor R68 is grounded. The VDD pin of the driver chip U35 is connected to the VCC_12V node, the GND pin of the driver chip U35 is grounded, the IN pin of the driver chip U35 receives the PWM signal from the MCU, and the OUT pin of the driver chip U35 is connected to the parallel branch of the resistor R4 and the diode D2. The resistors R14 and R13 are connected in parallel and then connected to pin 1 of the interface CN1 and ground, respectively. Pin 1 of the interface CN1 is connected to one end of the resistor R15, the other end of the resistor R15 is connected to one end of the capacitor C11, and the other end of the capacitor C11 is grounded.

6. The dual sensor based anti dry out control device as claimed in claim 1 wherein, The control circuit of the main control chip specifically includes: main control chip U23, capacitors C36, C37, C38, C43, C44, C45, C48, C56, C57, resistors R39, R68, R83, R94, LED5, inductor L11, crystal X3, debugging interface H2, and VCC_3V3 node; The VDD pin of the main control chip U23 is connected to the VCC_3V3 node, the VSS pin of the main control chip U23 is grounded, and capacitors C37, C38, C48 and C56 are connected in parallel between the VDD pin and the VSS pin of the main control chip U23. The other ends of capacitors C37, C38, C48 and C56 are all grounded. One end of the NRST pin of the main control chip U23 is connected to the resistor R39 and the capacitor C36, the other end of the resistor R39 is connected to the VCC_3V3 node, and the other end of the capacitor C36 is grounded, forming a reset circuit; The crystal X3, capacitor C43, and capacitor C44 constitute a clock circuit. The two ends of the crystal X3 are respectively connected to the OSC_IN pin and the OSC_OUT pin of the main control chip U23. One end of capacitor C43 and capacitor C44 are respectively connected to the OSC_IN pin and the OSC_OUT pin, and the other end is grounded. One end of the inductor L11 is connected to the VCC_3V3 node, and the other end is connected to the VDDA pin of the main control chip U23. The capacitors C37 and C38 are connected in parallel between the VDDA pin and ground. The anode of the light-emitting diode LED5 is connected to the resistor R68, the other end of the resistor R68 is connected to the VCC_3V3 node, and the cathode of the light-emitting diode LED5 is connected to the IO_RED pin of the main control chip U23. The debugging interfaces SWDIO, SWCLK, and NRST of the main control chip U23 are connected to the corresponding pins of the debugging interface H2, the power supply pin of the debugging interface H2 is connected to the VCC_3V3 node, and the ground pin of the debugging interface H2 is grounded. One end of the capacitor C45 and capacitor C57 connected in parallel is connected to the main control chip U23, and the other end is grounded; One end of the resistor R83 is connected to the VCC_3V3 node, and the other end of the resistor R83 is connected to the BOOT0 pin of the main control chip U23. One end of the resistor R94 is connected to the VOICE pin of the main control chip U23, and the other end is grounded.

7. The dual sensor based anti dry out control device as claimed in claim 1 wherein, The water level sensor has a built-in liquid level detection circuit. The liquid level detection circuit includes: a capacitive liquid level detection circuit and an infrared optical liquid level detection circuit; The capacitive liquid level detection circuit specifically includes: capacitor C66, connector CN4, and signal line LIQD_DETECT2; One end of the capacitor C66 is connected to the signal line LIQD_DETECT2, and the other end is grounded; Pin 3 of connector CN3 is connected to the VCC_3V3 node, pin 2 of connector CN3 is connected to the signal line LIQD_DETECT2, and pin 1 of connector CN3 is grounded. The infrared optical liquid level detection circuit specifically includes: resistor R97, capacitor C65, connector CN3, signal line LIQD_DETECT, and VCC_3V3 node; One end of the resistor R97 is connected to the VCC_3V3 node, the other end of the resistor R97 is connected to one end of the capacitor C65, the other end of the capacitor C65 is connected to the signal line LIQD_DETECT, the signal line LIQD_DETECT is connected to pin 2 of the connector CN3, and pin 1 of the connector CN3 is grounded.

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