A metal electrode oxidation protection circuit based on alternating power supply

Abstract

The utility model discloses a metal electrode oxidation protection circuit based on alternating power supply belongs to domestic appliance electronic circuit technical field, including control unit, temperature sensor and signal acquisition unit, the temperature sensor passes through the first metal electrode and second metal electrode of kettle body coupler and access circuit, the control unit includes first output pin and second output pin, the first output pin is connected to the second metal electrode, the second output pin is connected to the first metal electrode through first resistance, the input of signal acquisition unit is connected on the node between first resistance and second metal electrode, the utility model discloses through the low -frequency alternating power supply of unidirectional direct current power supply change, makes two metal electrode's polarity periodic exchange, no longer as anode continuously, thereby thoroughly eliminated electrochemical oxidation reaction's condition, fundamentally solved the contact oxidation problem.

Description

Technical Field

[0001] This utility model belongs to the field of electronic circuit technology of household appliances, and in particular relates to a metal electrode oxidation protection circuit based on alternating power supply. Background Technology

[0002] In products such as health-preserving kettles and tea makers, a coupler is usually installed at the bottom of the kettle body. This coupler connects to corresponding contacts on the base to provide power and control. The coupler typically contains five metal rings, two of which are dedicated to connecting to the temperature sensor (usually an NTC thermistor) inside the kettle.

[0003] like Figure 4 As shown in the conventional solution, in the existing technology, VCC is the positive power supply, CN1 is connected to pin 1 / 2 of the temperature sensor, GND is the negative power supply, and NTC is connected to the control chip pin to read the temperature signal. During operation, the main circuit is from VCC to CN1, then to resistor R18, and back to GND. NTC is the voltage signal used to read the temperature.

[0004] However, in actual use, moisture easily accumulates between the bottom of the kettle and the coupler on the base due to water evaporation and a humid environment. In the aforementioned unidirectional continuous power supply circuit, a continuous DC potential difference exists between the two metal contacts, creating conditions for water electrolysis. Under electrolysis, the metal contacts acting as the anode gradually undergo an oxidation reaction, generating a non-conductive oxide layer. This leads to increased contact resistance, ultimately causing problems such as inaccurate temperature sampling, control malfunction, or even complete poor contact, severely affecting the product's lifespan and reliability.

[0005] To address the electrode oxidation problem, several solutions have been proposed in the prior art. For example, prior art document 1 (CN114244342A) discloses a method for periodically switching the polarity of the two ends of the protected device using an H-bridge circuit composed of four switching transistors. However, this solution has a complex circuit structure, a large number of components, and high cost, making it difficult to widely apply in cost-sensitive small household appliances. Prior art document 2 (CN217202989U) uses a dual-relay scheme to switch the polarity of the electrodes in water electrolysis equipment, which also suffers from large size, high cost, and unsuitability for low-power signal sampling circuits.

[0006] Therefore, this utility model proposes a metal electrode oxidation protection circuit based on alternating power supply. Utility Model Content

[0007] The purpose of this invention is to provide a metal electrode oxidation protection circuit based on alternating power supply in order to solve at least one problem existing in the background technology.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a metal electrode oxidation protection circuit based on alternating power supply, comprising a control unit, a temperature sensor, and a signal acquisition unit, wherein the temperature sensor is connected to the circuit through the first metal electrode and the second metal electrode of the kettle body coupler, and the control unit includes a first output pin and a second output pin; The first output pin is connected to the second metal electrode; The second output pin is connected to the first metal electrode through a first resistor; The input terminal of the signal acquisition unit is connected to the node between the first resistor and the second metal electrode; The control unit is configured to periodically switch the level states of the first output pin and the second output pin so that the direction of the current flowing through the temperature sensor, the first metal electrode and the second metal electrode alternates.

[0009] As a further description of the above technical solution: The control unit is a microcontroller, and the output of the signal acquisition unit is connected to the ADC pin of the microcontroller.

[0010] As a further description of the above technical solution: The control logic executed by the control unit includes an alternating sampling phase and a reverse cleaning phase: During the sampling phase, the first output pin outputs a high level and the second output pin outputs a low level. During this period, the control unit reads the voltage signal through the signal acquisition unit. During the reverse cleaning phase, the first output pin outputs a low level, and the second output pin outputs a high level.

[0011] As a further description of the above technical solution: The duration of the sampling phase is equal to that of the reverse cleaning phase.

[0012] As a further description of the above technical solution: The time interval between the start of the sampling phase and the start of the next sampling phase constitutes a complete work cycle, the duration of which is 0.5 seconds to 10 seconds.

[0013] As a further description of the above technical solution: The temperature sensor is a negative temperature coefficient thermistor.

[0014] As a further description of the above technical solution: The circuit is used in health pots, tea makers, or electric kettles to protect the metal electrodes connecting the temperature sensor between the pot body and the base.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are: 1. Effectively prevents oxidation: By changing the unidirectional DC power supply to a low-frequency alternating power supply, the polarity of the two metal electrodes is periodically interchanged, and they no longer continuously act as the anode, thereby completely eliminating the conditions for electrochemical oxidation reaction and fundamentally solving the problem of contact oxidation.

[0016] 2. Simple circuit structure: No additional relays, switching transistors or complex H-bridge circuits are required. It can be implemented using only two general-purpose I / O ports of the MCU and a small number of external resistors, which greatly simplifies the circuit design and reduces hardware costs. Attached Figure Description

[0017] Figure 1 This is a circuit schematic diagram of an embodiment of the present invention.

[0018] Figure 2 This is a circuit diagram of the temperature sensor in an embodiment of this utility model.

[0019] Figure 3 This is a circuit diagram of the control unit in an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of a traditional unidirectional power supply circuit as described in the background art.

[0021] Legend: CN1-1, First metal electrode; CN1-2, Second metal electrode; NTC_N, First output pin; NTC_L, Second output pin; R18, First resistor; R19, Second resistor; C9, Capacitor; RT1, Temperature sensor; MCU, Microcontroller. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figures 1-4 This utility model provides a technical solution: such as Figure 1As shown, a metal electrode oxidation protection circuit based on alternating power supply includes a control unit, a temperature sensor RT1, and a signal acquisition unit. The temperature sensor RT1 is connected to the circuit through the first metal electrode CN1-1 and the second metal electrode CN1-2 of the kettle body coupler. The control unit includes a first output pin NTC_N and a second output pin NTC_L. The first output pin NTC_N is connected to the second metal electrode CN1-2; The second output pin NTC_L is connected to the first metal electrode CN1-1 through the first resistor R18; The input terminal of the signal acquisition unit is connected to the node between the first resistor R18 and the second metal electrode CN1-2; The control unit is configured to periodically switch the level states of the first output pin NTC_N and the second output pin NTC_L so that the direction of the current flowing through the temperature sensor RT1, the first metal electrode CN1-1 and the second metal electrode CN1-2 alternates. It also includes a second resistor R19 and a capacitor C9, wherein the first resistor R18, the second resistor R19 and the capacitor C9 are connected in series, and this structure is the same as that in the prior art.

[0024] In the specific embodiments of this application, such as Figure 3 As shown, Figure 3 In existing technology, the control unit is a microcontroller (MCU), and the output of the signal acquisition unit is connected to the ADC pin of the MCU.

[0025] In a specific embodiment of this application, the control logic executed by the control unit includes an alternating sampling phase and a reverse cleaning phase: During the sampling phase, the first output pin NTC_N outputs a high level and the second output pin NTC_L outputs a low level. During this period, the control unit reads the voltage signal through the signal acquisition unit. During the reverse cleaning phase, the first output pin NTC_N outputs a low level, and the second output pin NTC_L outputs a high level.

[0026] In a specific embodiment of this application, the duration of the sampling phase is equal to that of the reverse cleaning phase.

[0027] In a specific embodiment of this application, the time interval between the start of the sampling phase and the start of the next sampling phase constitutes a complete working cycle, and the duration of the working cycle is 0.5 seconds to 10 seconds.

[0028] In the specific embodiments of this application, such as Figure 2 As shown, Figure 2The circuit diagram shown is from the prior art, and the temperature sensor (RT1) is a negative temperature coefficient thermistor.

[0029] In a specific embodiment of this application, the circuit is applied in a health pot, tea maker, or electric kettle to protect the metal electrode connecting the temperature sensor between the pot body and the base.

[0030] The microcontroller MCU internal program follows Figure 3 The timing diagram shown periodically controls the voltage levels of the NTC_N and NTC_L pins.

[0031] Working principle: During operation, the main circuit flows from NTC_N (control chip output high level) to CN1, then to resistor R18, and back to NTC_L (control chip output low level). NTC is the voltage signal used to read the temperature. The levels are then reversed: NTC_N (control chip output low level), then NTC_L (control chip output high level). At this point, the NTC signal is not read; this cycle is repeated to avoid ionization issues.

[0032] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A metal electrode oxidation protection circuit based on alternating power supply, comprising a control unit, a temperature sensor (RT1), and a signal acquisition unit, wherein the temperature sensor (RT1) is connected to the circuit via a first metal electrode (CN1-1) and a second metal electrode (CN1-2) of a kettle body coupler, characterized in that: The control unit includes a first output pin (NTC_N) and a second output pin (NTC_L). The first output pin (NTC_N) is connected to the second metal electrode (CN1-2); The second output pin (NTC_L) is connected to the first metal electrode (CN1-1) through the first resistor (R18). The input terminal of the signal acquisition unit is connected to the node between the first resistor (R18) and the second metal electrode (CN1-2); The control unit is configured to periodically switch the level states of the first output pin (NTC_N) and the second output pin (NTC_L) so that the direction of the current flowing through the temperature sensor (RT1), the first metal electrode (CN1-1), and the second metal electrode (CN1-2) alternates.

2. The metal electrode oxidation protection circuit based on alternating power supply according to claim 1, characterized in that, The control unit is a microcontroller (MCU), and the output of the signal acquisition unit is connected to the ADC pin of the microcontroller (MCU).

3. The metal electrode oxidation protection circuit based on alternating power supply according to claim 1, characterized in that, The control logic executed by the control unit includes an alternating sampling phase and a reverse cleaning phase: During the sampling phase, the first output pin (NTC_N) outputs a high level, and the second output pin (NTC_L) outputs a low level. During this period, the control unit reads the voltage signal through the signal acquisition unit. During the reverse cleaning phase, the first output pin (NTC_N) outputs a low level, and the second output pin (NTC_L) outputs a high level.

4. The metal electrode oxidation protection circuit based on alternating power supply according to claim 3, characterized in that, The duration of the sampling phase is equal to that of the reverse cleaning phase.

5. The metal electrode oxidation protection circuit based on alternating power supply according to claim 3, characterized in that, The time interval between the start of the sampling phase and the start of the next sampling phase constitutes a complete work cycle, the duration of which is 0.5 seconds to 10 seconds.

6. The metal electrode oxidation protection circuit based on alternating power supply according to claim 1, characterized in that, The temperature sensor (RT1) is a negative temperature coefficient thermistor.

7. A metal electrode oxidation protection circuit based on alternating power supply according to any one of claims 1-6, characterized in that, The circuit is used in health pots, tea makers, or electric kettles to protect the metal electrodes connecting the temperature sensor between the pot body and the base.

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