Dry-burning-resistant electric heating faucet and control circuit thereof

Abstract

The utility model relates to an anti-dry-burning electric heating faucet and a control circuit thereof. The control circuit is provided with a main control unit, a temperature detection sensor, a water volume detection module, a heating switch module and a power module. A power supply module is adopted to convert voltage provided by a commercial power grid into set voltage for supplying power to a main control unit, a temperature detection sensor, a water quantity detection module and a heating switch module; the main control unit is used for determining the current water temperature in the water cavity through the temperature detected by the multiple temperature detection sensors, determining the current liquid level in the water cavity through the liquid level detected by the multiple liquid level detection sensors, and controlling the temperature of the water cavity to be higher than the preset water temperature when the current liquid level is not lower than the preset liquid level and the current water temperature is not higher than the preset water temperature. According to the electric heating water faucet, the water quantity of the electric heating water faucet is detected, heating is conducted again when the electric heating water faucet is full of water, dry burning of the electric heating water faucet is prevented, and the service life of the electric heating water faucet is prolonged.

Description

Technical Field

[0001] This application relates to the field of instant hot water appliance control technology, and in particular to an anti-dry-burning electric hot water faucet and its control circuit. Background Technology

[0002] An instant electric water heater is a type of water heater that can quickly heat flowing water using electronic heating elements and can control water temperature, flow rate, power, etc. through circuitry to bring the water temperature to a suitable temperature for bathing. It heats water instantly without waiting, and can usually start heating within a few seconds.

[0003] Electric water faucets are a relatively new product with advantages such as small size and easy modification. However, in some technologies, electric water faucets do not detect whether the water heater is full when they are working. They heat water directly after being powered on, which can lead to dry burning when there is insufficient water. This can easily damage the electric water faucet and reduce its service life.

[0004] Currently, no effective solution has been proposed for the problems of electric water faucets being prone to dry burning and damage in related technologies. Utility Model Content

[0005] In view of this, it is necessary to provide an anti-dry-burning electric water faucet and its control circuit, so as to at least solve the problems of easy dry burning and easy damage of electric water faucets in related technologies.

[0006] In a first aspect, this application provides a technical solution as follows: a control circuit for an anti-dry-burning electric water faucet, comprising a power module electrically connected to the mains power grid, a main control unit, a temperature detection sensor, a water volume detection module, and a heating switch module. The main control unit is electrically coupled to multiple temperature detection sensors, the water volume detection module, and the heating switch module, respectively. The heating switch module is also electrically connected to the mains power grid and two heating wires disposed within the water cavity of the electric water faucet. Multiple temperature detection sensors and multiple liquid level detection sensors of the water volume detection module are all disposed within the water cavity. The power module is used to convert the voltage provided by the mains power grid into a set voltage and transmit it to... The main control unit, the temperature detection sensor, the water volume detection module, and the heating switch module are powered. The main control unit is used to determine the current water temperature in the water cavity based on the temperatures detected by the multiple temperature detection sensors, and to determine the current liquid level in the water cavity based on the liquid levels detected by the multiple liquid level detection sensors. The heating switch module is used to control the connection and disconnection of at least one heating wire with the mains power grid, thereby controlling the power supply to the corresponding heating wire. The main control unit is also used to control at least one heating wire to be energized and heated when the current liquid level is not lower than a preset liquid level and the current water temperature is not higher than a preset water temperature.

[0007] Secondly, embodiments of this application also provide an anti-dry-burning electric water faucet, including a faucet body and a control board disposed on the faucet body, the control board being provided with a control circuit, the control circuit including the control circuit described in the first aspect.

[0008] Compared with related technologies, the anti-dry-burning electric water faucet and its control circuit provided in this embodiment adopt a main control unit, a temperature detection sensor, a water volume detection module, a heating switch module, and a power supply module. The power supply module converts the voltage provided by the mains power grid into a set voltage and supplies power to the main control unit, temperature detection sensor, water volume detection module, and heating switch module. The main control unit uses the temperature detected by multiple temperature detection sensors to determine the current water temperature in the water chamber, and uses the liquid level detected by multiple liquid level detection sensors to determine the current liquid level in the water chamber. When the current liquid level is not lower than the preset liquid level and the current water temperature is not higher than the preset water temperature, the main control unit controls the heating switch module to control one of the multiple heating wires to be energized for heating. By detecting the water volume of the electric water faucet and heating only when the water is full, the electric water faucet is prevented from dry-burning, thus extending its lifespan and solving the problems of easy dry-burning, easy damage, and short service life of electric water faucets in related technologies.

[0009] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0010] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention.

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a structural block diagram of the control circuit of the anti-dry-burning electric water faucet according to an embodiment of this application;

[0013] Figure 2 This is a topology diagram of the main control unit in an embodiment of this application;

[0014] Figure 3 This is a topology connection diagram of the main control unit and the heating switch module in an embodiment of this application;

[0015] Figure 4This is a topology connection diagram of the main control unit and the water detection module in an embodiment of this application;

[0016] Figure 5 This is a topology diagram of the main control unit and the temperature detection sensor in an embodiment of this application.

[0017] Figure 6 This is a structural block diagram of the control circuit of the anti-dry-burning electric water faucet according to a preferred embodiment of this application;

[0018] Figure 7 This is a topology diagram of the power module according to an embodiment of this application;

[0019] Figure 8 This is a topology diagram of the zero-crossing detection circuit of the power module according to an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The anti-dry-burning electric water faucet and its control circuit of this application will be described below with reference to the accompanying drawings in the embodiments of this application and through specific embodiments.

[0022] refer to Figures 1 to 8 The control circuit for the anti-dry-burning water heater provided in this application embodiment includes a connection to the mains power grid (see reference). Figure 1 , Figure 3 , Figure 6 , Figure 7 The power module 500 is electrically connected to the ACN and ACL (main control unit 100, temperature detection sensor 200, water volume detection module 300, and heating switch module 400). The main control unit 100 is electrically coupled to multiple temperature detection sensors 200, water volume detection module 300, and heating switch module 400 respectively. The heating switch module 400 is also electrically connected to the mains power grid and two heating wires 600 located in the water cavity of the electric water faucet. Multiple liquid level detection sensors 31 of the multiple temperature detection sensors 200 and water volume detection module 300 are all located in the water cavity.

[0023] The power module 500 is used to convert the voltage provided by the mains power grid into a set voltage and supply power to the main control unit 100, the temperature detection sensor 200, the water volume detection module 300 and the heating switch module 400.

[0024] In this embodiment, the power module 500 is used to convert the AC power (AC230V) provided by the mains power grid into a first voltage (+12V) corresponding to the first power supply, a second voltage (+5V) corresponding to the second power supply, and a third voltage (+3.3V) corresponding to the third power supply. That is, it converts the AC mains power into DC power and supplies power to the corresponding modules.

[0025] The main control unit 100 is used to determine the current water temperature in the water chamber based on the temperature detected by multiple temperature detection sensors 300, and to determine the current liquid level in the water chamber based on the liquid level detected by multiple liquid level detection sensors 31.

[0026] In this embodiment, multiple temperature sensors 200 are distributed within the water cavity of the electric water faucet. Each temperature sensor 200 sends the real-time detected water temperature to the main control unit 100. The main control unit 100 processes the received multiple water temperatures, for example, by averaging the multiple water temperatures or performing linear regression, and then calculates and determines the current water temperature within the water cavity. In this embodiment, reference... Figure 5 The water chamber is equipped with 5 temperature sensors (200, reference). Figure 5 CN10-CN14), and the positive terminal of each temperature sensor 200 is connected to a corresponding pull-up resistor (reference). Figure 5 R39, R42, R53, R66, and R69 are electrically connected to the third power supply (corresponding to a third voltage of +3.3V), and connected in series with the corresponding pull-down resistors (see reference). Figure 5 R40, R43, R54, R66, and R70 are connected to the negative terminal of the temperature sensor 200 and ground, and are also connected in series with corresponding coupling resistors (see reference). Figure 5 R38, R41, R52, R65, R68) and main control unit 100 (reference) Figure 5 The temperature sensor is electrically connected to the port corresponding to U4 in this embodiment; in this embodiment, the temperature detection sensor includes, but is not limited to, an NTC thermistor.

[0027] In this embodiment, the current water volume in the water chamber is processed in the same way as the current water temperature measurement. However, it should be understood that in this embodiment, the water volume detection module 300 processes the relevant parameters detected by the liquid level detection sensor 31 (e.g., capacitance changes caused by changes in the liquid level in the water chamber) to determine the corresponding liquid level sensed by each liquid level detection sensor 31. Then, the water volume detection module 300 sends the detected multiple liquid level data to the main control unit 100 for processing to determine the current liquid level and water volume in the water chamber.

[0028] In this embodiment, the main control unit 100 can be a single-chip microcomputer (MCU), a digital signal processor (DSP), or a programmable logic device (FPGA). In some optional embodiments, the main control unit 200 preferably uses one of the following MCUs: R7F0C908B2 microprocessor, STC15F204 single-chip microcomputer, AT89S52 single-chip microcomputer, or ESP32 microprocessor.

[0029] The heating switch module 400 is used to control the connection and disconnection of at least one heating wire 600 with the mains power grid, so as to control the power supply of the corresponding heating wire 600.

[0030] In this embodiment, the heating switch module 400 is used to switch the corresponding heating wire 600 to the working state according to the demand, and also controls the connection and disconnection between the heating wire 600 and the mains power grid, that is, controls the connection and disconnection between the heating wire 600 and the neutral wire and the live wire; it should be understood that in this embodiment, only one heating wire 600 is allowed to be in the working state during heating.

[0031] The main control unit 100 is also used to control the heating switch module 400 to control at least one heating wire 600 to be energized and heated when the current liquid level is not lower than the preset liquid level and the current water temperature is not higher than the preset water temperature.

[0032] In this embodiment, when the current liquid level is lower than the preset liquid level, it indicates that the water chamber is not full of water. At this time, regardless of the water temperature, the main control unit 100 will control the heating switch module 400 to cut off the power supply from the neutral and live wires of the mains power grid to the heating wire 600, so that neither of the two heating wires 600 will be energized and heated. When the current liquid level is not lower than the preset liquid level, that is, when the water chamber is full of water, if the water temperature is higher than the preset water temperature, it indicates that the water has been heated to the set temperature and there is no need to heat the water. At this time, the main control unit 100 will also control the heating switch module 400 to cut off the power supply from the neutral and live wires of the mains power grid to the heating wire 600. When the current liquid level is not lower than the preset liquid level and the current water temperature is not higher than the preset water temperature, it means that the water needs to be heated and the water chamber is full of water, and the heating will not dry-burn. At this time, the main control unit 100 will control the heating switch module 400 to control the selected heating wire 600 to be energized and then heat it. When the current water temperature is higher than the preset water temperature, if the current liquid level is not higher than the preset liquid level, it means that although the water in the water chamber is consumed, the water temperature still meets the preset requirements. At this time, the main control unit 100 will control the heating switch module 400 to cut off the power supply from the neutral wire and the live wire of the mains power grid to the heating wire 600, that is, the heating will not be started.

[0033] It is important to understand that while the heating switch module 400 disconnects the power supply from the neutral and live wires of the mains power grid, the power supply module 500 remains operational. The power supply module 500 is isolated from the switching control of the heating switch module 400.

[0034] The control circuit of the aforementioned anti-dry-burning electric water faucet includes a main control unit 100, a temperature detection sensor 200, a water volume detection module 300, a heating switch module 400, and a power supply module 500. The power supply module 500 converts the voltage provided by the mains power grid into a set voltage and supplies power to the main control unit 100, the temperature detection sensor 200, the water volume detection module, and the heating switch module. The main control unit uses multiple temperature detection sensors to determine the current water temperature in the water chamber and multiple liquid level detection sensors to determine the current liquid level in the water chamber. When the current liquid level is not lower than the preset liquid level and the current water temperature is not higher than the preset water temperature, the main control unit controls the heating switch module to energize one of the multiple heating wires for heating. By detecting the water volume of the electric water faucet and heating only when the water is full, the electric water faucet is prevented from dry-burning, thus extending its lifespan and solving the problems of easy dry-burning, easy damage, and short service life of electric water faucets in related technologies.

[0035] To achieve switching and power-on / off control of heating wire 600, refer to Figures 1 to 3 The heating switch module 400 includes a heating switching unit 41 and a heating control switch unit 42. The heating switching unit 41 includes a positive input port, a negative input port, a first positive output port, a first negative output port, a second positive output port, a second negative output port, and a first controlled terminal. The heating control switch unit 42 includes a first input port, a first output port, and a second controlled port. The positive and negative input ports are electrically connected to the first output ports of the two heating control switch units 42, respectively. The first and second positive output ports are electrically connected to the first ends of the two heating wires 600, respectively. The first and second negative output ports are electrically connected to the second ends of the two heating wires 600, respectively. Both the first and second controlled terminals are electrically coupled to the main control unit 100. The first input ports of the two heating control switch units 42 are electrically connected to the live wire and neutral wire of the mains power grid, respectively.

[0036] The main control unit 100 is used to send a heating switching control signal to the heating switching unit 41, and / or send a heating off signal to the heating control switching unit 42.

[0037] In this embodiment, the main control unit 100 generates a corresponding heating switching control signal according to preset requirements or selection, thereby switching the heating wire 600 currently in operation to a state disconnected from the live wire and neutral wire, and switching another heating wire 600 to the operation state; at the same time, the main control unit 100 also generates a corresponding heating shutdown signal according to the detected current water temperature and current liquid level in the water cavity, and sends it to the heating control switch unit 42, thereby controlling the connection and disconnection of the live wire and neutral wire with the positive input port and negative input port of the heating switching switch unit 41.

[0038] The heating switching unit 41 is used to synchronously control the positive input port to connect with one of the first positive output port and the second positive output port and to control the negative input port to connect with one of the first negative output port and the second negative output port according to the level of the heating switching control signal received by the first controlled terminal, so that one of the two heating wires 600 switches to the working state.

[0039] In this embodiment, when the heating switching control signal is at a preset high level, the heating switching unit 41 is driven to conduct, that is, the heating switching unit 41 starts switching operation. At this time, the positive input port is switched to be connected to the first positive output port, and the negative output port is switched to be connected to the first negative output port. The heating wire 600, which was previously in the working state, is switched to be disconnected from the mains power grid, while the heating wire 600, which was previously disconnected from the mains power grid, is switched to be connected to the mains power grid, that is, switched to the working state. When the heating switching control signal is at a preset low level, the heating switching unit 41 is in the off state. At this time, the heating wire 600, which was originally in the working state, remains in the working state.

[0040] The heating control switch unit 42 is used to control the on / off state of the first input port and the first output port of the corresponding heating control switch unit 42 according to the level of the heating off signal received by the second controlled terminal, so as to control the on / off state of the positive input port and the live wire and the negative input port and the neutral wire respectively.

[0041] In this embodiment, both the live wire and neutral wire of the mains power grid are electrically connected to a heating control switch unit 42, and the heating control switch unit 42 is located between the mains power grid and the heating switching switch unit 41. The heating control switch unit 42 controls the connection and disconnection between the neutral wire or live wire of the mains power grid and the negative input port or positive input port of the heating switching switch unit 41. In this embodiment, the main control unit 100 synchronously controls the two heating control switch units 42 to perform power-on / off control operations, that is, by controlling the disconnection or connection of the live wire and neutral wire. Specifically, when the heating switching... After the switching unit 41 selects the corresponding heating wire 600 to work, when the current liquid level is not lower than the preset liquid level and the current water temperature is not higher than the preset water temperature, the two heating control switching units 42 are in the conducting state. At this time, the live wire and neutral wire of the mains power grid are connected to the corresponding heating wire 600, and the heating wire 600 is energized to heat. When the current liquid level is lower than the preset liquid level and / or the current water temperature is higher than the preset water temperature, the main control unit 100 controls the two heating control switching units 42 to be in the disconnected state. At this time, the corresponding heating wire 600 is de-energized and stops heating.

[0042] To further enable switching of the heating wire 600, in some embodiments, reference is made to... Figure 3The heating switching unit 41 includes a dual-channel switching switch RL1 and a first switch driving circuit. The dual-channel switching switch RL1 includes a first port, a second port, a third port, a fourth port, a fifth port, a sixth port, and a seventh port. The first port is electrically connected to a first controlled terminal via the first switch driving circuit. The second port is connected to the positive input port, the third port is connected to the first positive output port, the fourth port is connected to the second positive output port, the fifth port is connected to the negative input port, the sixth port is connected to the first negative output port, and the seventh port is connected to the second negative output port.

[0043] The first switch driving circuit is used to convert the heating switching control signal received by the first controlled terminal into a first control signal.

[0044] A dual-channel switching switch is used to synchronously control the connection of the second port with one of the third and fourth ports and the fifth port with one of the sixth and seventh ports, based on a first control signal received at its first port.

[0045] In some optional embodiments, the dual-channel switching switch RL1 includes a double-pole double-throw relay. The double-pole double-throw relay includes a first pin, a second pin, a third pin, a fourth pin, a fifth pin, a sixth pin, a seventh pin, and an eighth pin. The second pin, third pin, fourth pin, fifth pin, sixth pin, seventh pin, and eighth pin are sequentially connected to the first port, the second port, the third port, the fourth port, the fifth port, the sixth port, and the seventh port. The first switch driving circuit includes a first clamping diode D6, a first switching transistor Q1, a first resistor R26, and a second resistor R25. The eighth pin is electrically connected to the first power supply (+12V) and the anode of the first clamping diode D6. The second pin is electrically connected to the cathode of the first clamping diode D6 and the input terminal of the first switching transistor Q1. The output terminal of the first switching transistor Q1 is grounded. The controlled terminal of the first switching transistor Q1 is connected to the first controlled terminal through a series first resistor R26 and pulled down to ground through a series second resistor R26.

[0046] The first switch Q1 is used to control the on / off state of the input and output terminals of the first switch Q1 according to the level of the heating switching control signal received by its controlled terminal, so as to generate a corresponding first control signal.

[0047] A double-pole double-throw relay is used to synchronously control the connection between the third and fifth pins and the sixth and eighth pins when the level of the first control signal received at the second pin is a preset high level, and to synchronously control the connection between the third and fourth pins and the sixth and seventh pins when the level of the first control signal received at the second pin is a preset low level.

[0048] It is understood that the first switching transistor Q1 in the embodiments of this application includes, but is not limited to, transistors, MOSFETs, and field-effect transistors. Furthermore, based on the disclosure of this application, those skilled in the art can readily conceive of modifying the first switching transistor Q1 disclosed in this application into a first switching drive circuit adapted to the specific selection of the switching transistor. Therefore, this application can be implemented regardless of whether the switching transistor is an NPN or PNP transistor, an N-channel or P-channel switching MOSFET, or an N-type or P-type field-effect transistor. This application is not limited in the embodiments of this application.

[0049] To further achieve on / off control of the heating wire 600, refer to Figure 3 In some embodiments, the heating control switch unit 42 includes a first controlled switch (see reference 1). Figure 3 The first controlled switch includes a first terminal, a second terminal, a third terminal, and a fourth terminal, and the second switch driving circuit includes a second switching transistor (see reference). Figure 3 Q2 and Q3 in the middle), the third resistor (reference) Figure 3 (R28 and R30 in the middle) and the fourth resistor (reference) Figure 3 In the circuit (R27 and R29), the first terminal is electrically connected to the input terminal of the second switching transistor, the second terminal is electrically connected to the first power supply, the third terminal is connected to the first input port, the fourth terminal is connected to the first output port, the output terminal of the second switching transistor is grounded, and the controlled terminal of the second switching transistor is connected to the second controlled terminal through a series third resistor, and is also pulled down to ground through a series third resistor.

[0050] The second switch is used to control the on / off state of its input and output terminals according to the level of the heating off signal received at its controlled terminal, so as to generate a corresponding second control signal at the input terminal of the second switch.

[0051] The second switch driving circuit is used to generate a second control signal and output the second control signal to the first terminal of the first controlled switch.

[0052] The first controlled switch is used to control the on / off state of the third and fourth ports of the first controlled switch according to the level of the received second control signal, so as to control the on / off state of the positive input port and the live wire and the negative input port and the neutral wire respectively.

[0053] In this embodiment, the first controlled switch includes, but is not limited to, a single-pole single-throw relay. The second switching transistor in this embodiment includes, but is not limited to, a transistor, a MOSFET, or a field-effect transistor. Furthermore, based on the disclosure of this application, those skilled in the art can readily conceive of modifying the second switching transistor disclosed in this application into a second switching drive circuit adapted to the specific selection of the switching transistor. Therefore, this application can be implemented regardless of whether the switching transistor is an NPN or PNP transistor, an N-channel or P-channel switching MOSFET, or an N-type or P-type field-effect transistor. This application is not limited in this embodiment.

[0054] To detect the current liquid level within the water chamber, refer to Figure 1 and Figure 4 In some embodiments, the water level detection module 300 further includes a digital capacitive sensing control chip electrically connected to the power supply module 500 (see reference). Figure 4 The digital capacitive sensing control chip (U7) is also electrically connected to multiple liquid level detection sensors 31. The digital capacitive sensing control chip is used to sense the capacitance change when multiple liquid level detection sensors 31 are placed in the water cavity, and to measure the corresponding current liquid level in the water cavity according to the corresponding capacitance change.

[0055] In this embodiment, the digital capacitive sensing control chip includes, but is not limited to, one of the following: MC12G / T, NE5532DR, MC11, and MDC04.

[0056] To display the current water temperature and level, refer to Figure 6 In some embodiments, an LED display module 700 electrically connected to the main control unit 100 is also included. The LED display module 700 is used to display the current water temperature and the water volume information corresponding to the current liquid level.

[0057] In this embodiment, the LED display module 700 can be a display module composed of RGB display chips. It is understood that any existing RGB display chip can constitute the LED display module 700 in this application, and no limitation is made here.

[0058] In some embodiments, to convert AC power from the municipal power grid into DC power, reference is made. Figure 1 , Figures 6 to 8 The power module 500 includes:

[0059] The EMC rectifier circuit includes a varistor VR1, a filter capacitor X1, and a rectifier bridge B1. The varistor VR1 and filter capacitor X1 form a filter unit. The input of the filter unit is connected to the mains power grid, and its output is connected to the input of the rectifier bridge B1. The output of the rectifier bridge B1 is coupled to the high-voltage output port (reference) through a first inductor L1. Figure 7 (The electrical connection point between L1 and resistors R5 and R7).

[0060] In this embodiment, capacitors EC1 and EC2 are also provided at both ends of the first inductor L1, and the capacitors EC1 and EC2 together with the first inductor L1 form an LCπ-type filter network for output filtering; in this embodiment, the high voltage output from the high voltage output port corresponds to a level of 330V.

[0061] The inverter transformer TF1 includes a primary winding, a secondary winding, and an auxiliary winding. The primary winding is electrically coupled to the high-voltage output port.

[0062] The control circuit includes a switching power supply control chip U1. The power supply port VDD of the switching power supply control chip U1 is electrically connected to the high-voltage output port through a voltage divider circuit composed of multiple resistors (R5 and R6) connected in series. The power supply port VDD is also electrically connected to the corresponding terminal of the auxiliary winding through a voltage regulator circuit composed of a first diode D3 and a first current-limiting resistor R9 connected in series. The feedback port INV of the switching power supply control chip U1 is also electrically connected to the corresponding terminal of the auxiliary winding through a positive feedback circuit composed of multiple sampling resistors (R10 and R11) connected in series. The power switch control port of the switching power supply control chip U1 (reference)... Figure 7 Pin 8 of U1 is electrically connected to the same terminal of the primary winding. The secondary winding is electrically connected to the first power output port through the output rectifier circuit. The output rectifier circuit includes parallel rectifier diode D4, RC snubber network (composed of R14 and C4) and first common mode filter network (composed of C5, L2, EC5 and L3).

[0063] The voltage regulator module includes a cascaded first linear regulator chip U2 and a second linear regulator chip U3. The first power output port is electrically connected to the input terminal of the first linear regulator chip U2 via a series second current-limiting resistor (composed of R18 and R19). The output terminal of the first linear regulator chip U2 is electrically connected to the second power (+5V) output port and the input terminal of the second linear regulator chip U3 via a second common-mode filter network (composed of EC7, L4, EC8, and L5). The output terminal of the second linear regulator chip U3 is electrically connected to the third power output port (corresponding to a +3.3V output).

[0064] EMC rectifier circuits are used to convert mains voltage into a high voltage at a preset level.

[0065] The auxiliary winding is used to supply power to the switching power supply control chip U1 after it starts up based on high voltage.

[0066] The switching power supply control chip U1 is used to obtain a status signal reflecting the high voltage through a positive feedback circuit, so as to control the internal power switch to turn on / off, and enable the inverter transformer TF1 to convert the high voltage into a high-frequency square wave pulse voltage and output it along the secondary winding.

[0067] In this embodiment, the switching power supply control chip U1 includes, but is not limited to, the ME4057 chip.

[0068] The output rectifier circuit is used to rectify the high-frequency square wave pulse voltage into the first voltage corresponding to the first power supply and then output it along the first power supply port.

[0069] The first linear regulator chip U2 is used to regulate the first voltage to the second voltage corresponding to the second power supply.

[0070] The second linear regulator chip U3 is used to regulate the second voltage to the third voltage corresponding to the third power supply.

[0071] It should be noted that the reference Figure 8 The control circuit of this application is also provided with a corresponding zero-crossing detection circuit. The zero-crossing detection circuit is coupled and electrically connected to the main control unit 100 and the power module 500. The main control unit 100 generates a corresponding zero-crossing control signal according to the magnitude of the zero-crossing detection signal, and controls the power module 100 to work based on the corresponding zero-crossing control signal.

[0072] This application embodiment also provides an anti-dry-burning electric water faucet, including a faucet body and a control board disposed on the faucet body. The control board is provided with a control circuit, which is the control circuit of the anti-dry-burning electric water faucet in the above embodiment.

[0073] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive elements that are not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0074] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A control circuit for an anti-dry-burning electric water faucet, characterized in that, The system includes a power module (500) electrically connected to the mains power grid, a main control unit (100), a temperature sensor (200), a water level detection module (300), and a heating switch module (400). The main control unit (100) is electrically coupled to multiple temperature sensors (200), water level detection modules (300), and heating switch modules (400). The heating switch module (400) is also electrically connected to the mains power grid and two heating wires (600) located in the water cavity of the electric water faucet. Multiple temperature sensors (200) and multiple liquid level detection sensors (31) of the water level detection module (300) are located in the water cavity. The power module (500) is used to convert the voltage provided by the main grid into a set voltage and supply power to the main control unit (100), the temperature detection sensor (200), the water volume detection module (300) and the heating switch module (400); The main control unit (100) is used to determine the current water temperature in the water cavity based on the temperature detected by the multiple temperature detection sensors (200), and to determine the current liquid level in the water cavity based on the liquid level detected by the multiple liquid level detection sensors (31); The heating switch module (400) is used to control the connection and disconnection of at least one of the heating wires (600) with the mains power grid, so as to control the power supply of the corresponding heating wire (600). The main control unit (100) is also used to control at least one of the heating wires (600) to be energized and heated by the heating switch module (400) when the current liquid level is not lower than the preset liquid level and the current water temperature is not higher than the preset water temperature.

2. The control circuit according to claim 1, characterized in that, The heating switch module (400) includes a heating switching unit (41) and a heating control switch unit (42). The heating switching unit (41) includes a positive input port, a negative input port, a first positive output port, a first negative output port, a second positive output port, a second negative output port, and a first controlled terminal. The heating control switch unit (42) includes a first input port, a first output port, and a second controlled port. The positive input port and the negative input port are electrically connected to the first output ports of the two heating control switch units (42), respectively. The first positive output port and the second positive output port are electrically connected to the first ends of the two heating wires (600), respectively. The first negative output port and the second negative output port are electrically connected to the second ends of the two heating wires (600), respectively. The first controlled terminal and the second controlled terminal are both coupled and electrically connected to the main control unit (100). The first input ports of the two heating control switch units (42) are electrically connected to the live wire and the neutral wire of the mains power grid, respectively. The main control unit (100) is used to send a heating switching control signal to the heating switching unit (41) and / or send a heating off signal to the heating control switching unit (42); The heating switching unit (41) is used to synchronously control the positive input port to connect with one of the first positive output port and the second positive output port and control the negative input port to connect with one of the first negative output port and the second negative output port according to the level of the heating switching control signal received by the first controlled terminal, so that one of the two heating wires (600) switches to the working state; The heating control switch unit (42) is used to control the on / off state of the first input port and the first output port of the corresponding heating control switch unit (42) according to the level of the heating off signal received by the second controlled terminal, so as to control the on / off state of the positive input port and the live wire and the negative input port and the neutral wire respectively.

3. The control circuit according to claim 2, characterized in that, The heating switching unit (41) includes a dual-channel switching switch and a first switch driving circuit. The dual-channel switching switch includes a first port, a second port, a third port, a fourth port, a fifth port, a sixth port, and a seventh port. The first port is electrically connected to the first controlled terminal through the first switch driving circuit. The second port is connected to the positive input port, the third port is connected to the first positive output port, the fourth port is connected to the second positive output port, the fifth port is connected to the negative input port, the sixth port is connected to the first negative output port, and the seventh port is connected to the second negative output port. The first switch driving circuit is used to convert the heating switching control signal received by the first controlled terminal into a first control signal; The dual-channel switching switch is used to synchronously control the second port to connect with one of the third and fourth ports and the fifth port to connect with one of the sixth and seventh ports according to the first control signal received by its first port.

4. The control circuit according to claim 3, characterized in that, The dual-channel switching switch includes a double-pole double-throw relay, which includes a first pin, a second pin, a third pin, a fourth pin, a fifth pin, a sixth pin, a seventh pin, and an eighth pin. The second pin, the third pin, the fourth pin, the fifth pin, the sixth pin, the seventh pin, and the eighth pin are sequentially connected to the first port, the second port, the third port, the fourth port, the fifth port, the sixth port, and the seventh port, respectively. The first switch driving circuit includes a first clamping diode, a first switching transistor, a first resistor, and a second resistor. The eighth pin is electrically connected to a first power supply and the anode of the first clamping diode. The second pin is electrically connected to the cathode of the first clamping diode and the input terminal of the first switching transistor. The output terminal of the first switching transistor is grounded. The controlled terminal of the first switching transistor is connected to the first controlled terminal through series connection of the first resistor and pulled down to ground through series connection of the second resistor. The first switching transistor is used to control the on / off state of the input and output terminals of the first switching transistor according to the level of the heating switching control signal received by its controlled terminal, so as to generate the corresponding first control signal. The double-pole double-throw relay is used to simultaneously control the connection between the third pin and the fifth pin, and between the sixth pin and the eighth pin when the level of the first control signal received by the second pin is a preset high level, and to simultaneously control the connection between the third pin and the fourth pin, and between the sixth pin and the seventh pin when the level of the first control signal received by the second pin is a preset low level.

5. The control circuit according to claim 3, characterized in that, The heating control switch unit (42) includes a first controlled switch and a second switch driving circuit. The first controlled switch includes a first terminal, a second terminal, a third terminal, and a fourth terminal. The second switch driving circuit includes a second switching transistor, a third resistor, and a fourth resistor. The first terminal is electrically connected to the input terminal of the second switching transistor, the second terminal is electrically connected to a first power supply, the third terminal is connected to the first input port, the fourth terminal is connected to the first output port, the output terminal of the second switching transistor is grounded, and the controlled terminal of the second switching transistor is connected to the second controlled terminal through the third resistor in series and pulled down to ground through the third resistor in series. The second switching transistor is used to control the on / off state of the input and output terminals of the second switching transistor according to the level of the heating off signal received at its controlled terminal, so as to generate a corresponding second control signal at the input terminal of the second switching transistor. The second switch driving circuit is used to generate the second control signal and output the second control signal to the first terminal of the first controlled switch; The first controlled switch is used to control the on / off state of the third and fourth ports of the first controlled switch according to the level of the received second control signal, so as to control the on / off state of the positive input port and the live wire and the on / off state of the negative input port and the neutral wire respectively.

6. The control circuit according to claim 5, characterized in that, The first controlled switch includes a relay.

7. The control circuit according to claim 1, characterized in that, The water volume detection module (300) also includes a digital capacitive sensing control chip electrically connected to the power module (500). The digital capacitive sensing control chip is also electrically connected to multiple liquid level detection sensors (31). The digital capacitive sensing control chip is used to sense the capacitance change when multiple liquid level detection sensors (31) are placed in the water cavity, and to measure the corresponding current liquid level in the water cavity according to the corresponding capacitance change.

8. The control circuit according to any one of claims 1 to 7, characterized in that, It also includes an LED display module (700) electrically connected to the main control unit (100), the LED display module (700) being used to display the current water temperature and the water volume information corresponding to the current liquid level.

9. The control circuit according to claim 8, characterized in that, The power module (500) includes: The EMC rectifier circuit includes a varistor, a filter capacitor, and a rectifier bridge. The varistor and the filter capacitor form a filter unit. The input terminal of the filter unit is connected to the mains power grid, and its output terminal is connected to the input terminal of the rectifier bridge. The output terminal of the rectifier bridge is connected to the high-voltage output port through a first inductive coupling. The inverter transformer includes a primary winding, a secondary winding, and an auxiliary winding, wherein the primary winding is electrically coupled to the high-voltage output port; The control circuit includes a switching power supply control chip. The power supply port of the switching power supply control chip is electrically connected to the high-voltage output port through a voltage divider circuit composed of multiple resistors connected in series. The power supply port is also electrically connected to the same-name terminal of the auxiliary winding through a voltage regulator circuit composed of a first diode and a first current-limiting resistor connected in series. The feedback port of the switching power supply control chip is also electrically connected to the same-name terminal of the auxiliary winding through a positive feedback circuit composed of multiple sampling resistors connected in series. The power switch control port of the switching power supply control chip is electrically connected to the same-name terminal of the primary winding. The secondary winding is electrically connected to the first power output port through an output rectifier circuit. The output rectifier circuit includes a rectifier diode, an RC snubber network, and a first common-mode filter network connected in parallel. The voltage regulator module includes a cascaded first linear voltage regulator chip and a second linear voltage regulator chip. The first power output port is electrically connected to the input terminal of the first linear voltage regulator chip via a series second current-limiting resistor. The output terminal of the first linear voltage regulator chip is electrically connected to both the second power output port and the input terminal of the second linear voltage regulator chip via a second common-mode filter network. The output terminal of the second linear voltage regulator chip is electrically connected to a third power output port. The EMC rectifier circuit is used to convert the mains voltage into a high voltage at a preset level. The auxiliary winding is used to supply power to the switching power supply control chip after it starts up based on the high voltage. The switching power supply control chip is used to obtain a status signal reflecting the high voltage through the positive feedback circuit, so as to control the internal power switch to be turned on / off, and to make the inverter transformer convert the high voltage into a high-frequency square wave pulse voltage and output it along the secondary winding. The output rectifier circuit is used to rectify the high-frequency square wave pulse voltage into a first voltage corresponding to the first power supply and then output it along the first power supply port. The first linear voltage regulator chip is used to regulate the first voltage to the second voltage corresponding to the second power supply; The second linear voltage regulator chip is used to regulate the second voltage to the third voltage corresponding to the third power supply.

10. An anti-dry-burning electric water faucet, comprising a faucet body and a control board disposed on the faucet body, wherein the control board is provided with a control circuit, characterized in that, The control circuit includes the control circuit according to any one of claims 1 to 9.

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