NTC resistor protection circuits, surge protection circuits, power supply circuits, and household appliances

Abstract

This invention provides an NTC resistor protection circuit, a surge protection circuit, a power supply circuit, and a household appliance. In the NTC resistor protection circuit, at least two NTC resistor paths are connected in parallel between a first power input terminal and a first power output terminal. Each NTC resistor path includes a control switch and an NTC resistor, which are connected in series between the first power input terminal and the first power output terminal. The control terminal of the control switch is electrically connected to the main control chip. A temperature detection unit is electrically connected to the main control chip. The temperature detection unit detects the temperature of the NTC resistor in each NTC resistor path and sends a temperature detection signal to the main control chip. The main control chip switches the conduction or deactivation of each NTC resistor path based on the temperature detection signal. This invention solves the problem that due to prolonged operation, the NTC resistor heats up, and upon restarting, the resistance decreases due to the higher temperature, resulting in a reduced surge current suppression capability and hindering rapid startup.

Description

Technical Field

[0001] This utility model relates to the field of surge protection technology, specifically to an NTC resistor protection circuit, a surge protection circuit using the NTC resistor protection circuit, a power supply circuit using the surge protection circuit, and a household appliance using the power supply circuit. Background Technology

[0002] At the moment of power-on, the input capacitor charges rapidly, resulting in a large peak value of the input inrush current, which may damage components in the circuit. An NTC resistor is typically connected in series in the circuit to suppress the inrush current. However, NTC resistors are more effective at suppressing inrush current at low temperatures due to their higher resistance; as the temperature increases, their resistance decreases, and their suppression capability weakens.

[0003] In an existing NTC surge protection circuit, there is a risk of damage to the NTC itself due to overheating. Therefore, a relay switch is connected in parallel across the NTC resistor to protect the NTC resistor by detecting its temperature. When the temperature is too high, the relay is directly switched to short-circuit the NTC resistor, thus protecting it. However, this solution cannot effectively suppress surge current when the power is repeatedly turned on and off and the NTC temperature is too high, which can easily lead to circuit failure.

[0004] Therefore, a more optimized NTC resistor protection circuit needs to be considered. Utility Model Content

[0005] The primary objective of this invention is to provide an NTC resistor protection circuit that can solve the problem of NTC resistors overheating during prolonged operation, causing their resistance to decrease upon restarting due to higher temperatures, resulting in a reduced ability to suppress surge current and thus preventing rapid startup.

[0006] The second objective of this invention is to provide a surge protection circuit that can solve the problem of NTC resistors heating up during long-term operation, causing their resistance to decrease upon restarting due to higher temperature, resulting in a reduced ability to suppress surge current and thus preventing rapid startup.

[0007] The third objective of this invention is to provide a power supply circuit that can solve the problem of NTC resistors overheating during long-term operation, causing their resistance to decrease upon restarting due to higher temperatures, resulting in a reduced ability to suppress surge current and thus preventing rapid startup.

[0008] The fourth objective of this invention is to provide a household appliance that can solve the problem of NTC resistors overheating during prolonged operation, causing their resistance to decrease upon restarting due to higher temperatures, resulting in a reduced ability to suppress surge current and thus preventing rapid startup.

[0009] To achieve the aforementioned first objective, the NTC resistor protection circuit provided by this utility model includes at least two NTC resistor paths, a first power input terminal, a first power output terminal, a temperature detection unit, and a main control chip; at least two NTC resistor paths are connected in parallel between the first power input terminal and the first power output terminal; each NTC resistor path includes a control switch and an NTC resistor, which are connected in series between the first power input terminal and the first power output terminal, and the control terminal of the control switch is electrically connected to the main control chip; the temperature detection unit is electrically connected to the main control chip; the temperature detection unit is used to detect the temperature of the NTC resistor in each NTC resistor path and send a temperature detection signal to the main control chip; the main control chip is used to switch the conduction or deactivation of each NTC resistor path according to the temperature detection signal.

[0010] As can be seen from the above solution, the NTC resistor protection circuit of this utility model sets up at least two parallel NTC resistor paths. Each NTC resistor path is equipped with a control switch and an NTC resistor. The temperature detection unit detects the temperature of each NTC resistor, and the main control chip switches the conduction or deactivation of the NTC resistor path according to the temperature detection signal. This enables the circuit to disconnect the corresponding path when the temperature of the NTC resistor is too high and conduct the path corresponding to the NTC resistor with a lower temperature. This solves the problem that the NTC resistor heats up after long-term operation, and the resistance decreases when restarting due to the high temperature, which reduces the ability to suppress surge current and prevents rapid restart.

[0011] In a further embodiment, the temperature detection unit includes a number of temperature sensing elements equal to the number of NTC resistors. Each temperature sensing element detects the temperature of one NTC resistor, and each temperature sensing element is electrically connected to the main control chip.

[0012] Therefore, it can be seen that the temperature detection unit can detect each NTC resistor by setting an equal number of temperature sensing elements on the NTC resistors, thus ensuring the accuracy of temperature detection.

[0013] In a further embodiment, the temperature sensing element includes a temperature sensor or a thermistor.

[0014] Therefore, the temperature sensing element uses a temperature sensor or a thermistor, which can easily output analog or digital signals according to temperature changes for temperature detection.

[0015] In a further embodiment, the first end of the control switch is electrically connected to the first power input terminal, the second end of the control switch is electrically connected to the first end of the NTC resistor, and the second end of the NTC resistor is electrically connected to the first power output terminal.

[0016] Therefore, placing the control switch before the NTC resistor can further protect the NTC resistor.

[0017] In a further proposed design, the control switch is a single-pole single-throw relay switch.

[0018] In a further embodiment, the first switching terminal of the single-pole single-throw relay switch is electrically connected to the first power input terminal, the second switching terminal of the single-pole single-throw relay switch is electrically connected to the first terminal of the NTC resistor, the first electromagnetic terminal of the single-pole single-throw relay switch is electrically connected to the power supply terminal, and the first electromagnetic terminal of the single-pole single-throw relay switch is electrically connected to the main control chip.

[0019] Therefore, using a relay switch as the control switch can ensure the effectiveness of the switch on / off control.

[0020] In a further proposed solution, the control switch is a switching transistor.

[0021] In a further embodiment, the first terminal of the switching transistor is electrically connected to the first power input terminal, the second terminal of the switching transistor is electrically connected to the first terminal of the NTC resistor, and the control terminal of the switching transistor is electrically connected to the main control chip.

[0022] Therefore, using a switching transistor as a control switch can improve the control response speed and the power supply start-up speed.

[0023] To achieve the second objective of this utility model, the surge protection circuit provided by this utility model includes an NTC resistor protection circuit, an energy storage capacitor, a first terminal, a second terminal, a first load output terminal, and a second load output terminal. The first terminal is electrically connected to the first load output terminal, and the second terminal is electrically connected to the second load output terminal. The energy storage capacitor is connected in parallel between the first load output terminal and the second load output terminal. The NTC resistor protection circuit is connected in series between the first terminal and the first terminal of the energy storage capacitor or between the second terminal and the second terminal of the energy storage capacitor. The NTC resistor protection circuit uses the aforementioned NTC resistor protection circuit.

[0024] To achieve the third objective of this utility model, the power supply circuit provided by this utility model includes a surge protection circuit, which applies the surge protection circuit described above.

[0025] To achieve the fourth objective of this utility model, the household appliance provided by this utility model includes a power supply circuit, which uses the power supply circuit described above. Attached Figure Description

[0026] Figure 1 This is a circuit diagram of the first embodiment of the surge protection circuit of this utility model.

[0027] Figure 2 This is a circuit diagram of the NTC resistor protection circuit in the first embodiment of the surge protection circuit of this utility model.

[0028] Figure 3This is a circuit diagram of the NTC resistor protection circuit in the first embodiment of the surge protection circuit of this utility model.

[0029] Figure 4 This is a circuit diagram of the NTC resistor protection circuit in the second embodiment of the surge protection circuit of this utility model.

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0031] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present invention or its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0032] The terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0033] In this invention, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not exist between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may not be directly connected to the other devices but may have an intermediary device.

[0034] All terms used in this invention (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0035] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0036] First embodiment of surge protection circuit:

[0037] like Figure 1 As shown, in this embodiment, the surge protection circuit includes an NTC resistor protection circuit 1, an energy storage capacitor C, a first terminal AL, a second terminal AN, a first load output terminal AL0, and a second load output terminal AN0. The first terminal AL is electrically connected to the first load output terminal AL0, and the second terminal AN is electrically connected to the second load output terminal AN0. The energy storage capacitor C is connected in parallel between the first load output terminal AL0 and the second load output terminal AN0. The NTC resistor protection circuit 1 is connected in series between the first terminal of the energy storage capacitor C and the first terminal AL. A fuse F is provided between the second terminal of the energy storage capacitor C and the second terminal AN.

[0038] Of course, the NTC resistor protection circuit 1 can also be connected in series between the second terminal of the energy storage capacitor C and the second terminal AN.

[0039] In this embodiment, see Figure 2 The NTC resistor protection circuit 1 includes at least two NTC resistor paths 11, a first power input terminal L1, a first power output terminal L2, a temperature detection unit 12, and a main control chip 13. The at least two NTC resistor paths 11 are connected in parallel between the first power input terminal L1 and the first power output terminal L2. The number of NTC resistor paths 11 can be set as needed; preferably, there are two NTC resistor paths 11.

[0040] Each NTC resistor path 11 includes a control switch 111 and an NTC resistor R1. The control switch 111 and the NTC resistor R1 are connected in series between the first power input terminal L1 and the first power output terminal L2. The control terminal of the control switch 111 is electrically connected to the main control chip 13. The first power input terminal L1 is electrically connected to the first terminal AL, and the first power output terminal L2 is electrically connected to the first terminal of the energy storage capacitor C. The temperature detection unit 12 is electrically connected to the main control chip 13. The temperature detection unit 12 is used to detect the temperature of the NTC resistor R1 in each NTC resistor path 11 and send a temperature detection signal to the main control chip 13. The main control chip 13 is used to switch the conduction or deactivation of each NTC resistor path 11 according to the temperature detection signal.

[0041] In this embodiment, the temperature detection unit 12 includes temperature sensing elements 121 in a number equal to the number of NTC resistors R1. Each temperature sensing element 121 detects the temperature of one NTC resistor R1, and each temperature sensing element 121 is electrically connected to the main control chip 13. The temperature sensing element 121 includes a temperature sensor or a thermistor. By using a number of temperature sensing elements 121 equal to the number of NTC resistors R1, the temperature detection unit 12 can detect the temperature of each NTC resistor R1, ensuring the accuracy of temperature detection. The use of temperature sensors or thermistors in the temperature sensing elements 121 facilitates the output of analog or digital signals based on temperature changes for temperature detection.

[0042] In this embodiment, the first terminal of the control switch 111 is electrically connected to the first power input terminal L1, the second terminal of the control switch 111 is electrically connected to the first terminal of the NTC resistor R1, and the second terminal of the NTC resistor R1 is electrically connected to the first power output terminal L2. By placing the control switch 111 before the NTC resistor R1, the NTC resistor R1 can be further protected.

[0043] In this embodiment, see Figure 3 The control switch 111 is a single-pole single-throw relay switch K1. The first switching terminal of the single-pole single-throw relay switch K1 is electrically connected to the first power input terminal L1, the second switching terminal of the single-pole single-throw relay switch K1 is electrically connected to the first terminal of the NTC resistor R1, the first electromagnetic terminal of the single-pole single-throw relay switch K1 is electrically connected to the power supply terminal, and the first electromagnetic terminal of the single-pole single-throw relay switch K1 is electrically connected to the main control chip 13 through terminal RLT1. Using a relay switch as the control switch 111 ensures the effectiveness of the switch on / off control.

[0044] In this embodiment, when the surge protection circuit is powered on, the temperature detection unit 12 detects the temperature of each NTC resistor R and sends the data to the main control chip 13. The main control chip 13 outputs a relay control signal to the control switch 111 based on the actual temperature. When the temperature of all NTC resistors R is lower than a preset temperature value (which ensures the NTC resistance meets the charging current limit), the main control chip 13 outputs a control signal to the control switch 111 corresponding to one NTC resistor R1 in a preset order, causing the control switch 111 to turn on the corresponding NTC resistor path 11. Simultaneously, it controls the other NTC resistor paths 11 to turn off.

[0045] As the NTC resistor R1 operates within the circuit, its temperature gradually increases. When the power supply experiences a load anomaly or a short circuit in the downstream circuit, the temperature of the NTC resistor R1 may exceed the second preset temperature. In this case, the main control chip 13 outputs a control signal to the control switch 111 corresponding to the NTC resistor R1, causing the control switch 111 to disconnect the corresponding NTC resistor path 11. Simultaneously, a disconnected NTC resistor path 11 can be switched on according to a preset sequence, thus achieving the switching of the NTC resistor path 11. This method ensures that even after prolonged operation and when one NTC resistor R1 heats up to a high temperature, a suitable NTC resistor path 11 can be activated upon power restart to suppress inrush current and achieve rapid startup.

[0046] Second embodiment of surge protection circuit:

[0047] The surge protection circuit in this embodiment differs from that in the first embodiment only in the control switch 111. The differences will be described below, and the reference numerals will follow those of the first embodiment.

[0048] See Figure 4 In this embodiment, the control switch 111 is a switching transistor Q1. The first terminal of the switching transistor Q1 is electrically connected to the first power input terminal L1, the second terminal of the switching transistor Q1 is electrically connected to the first terminal of the NTC resistor R1, and the control terminal of the switching transistor Q1 is electrically connected to the main control chip 13 through terminal A1. The switching transistor Q1 can be a MOSFET or a field-effect transistor. Using the switching transistor Q1 as the control switch 111 can improve the control response speed and the power-on speed.

[0049] As described above, the NTC resistor protection circuit 1 of this utility model sets at least two parallel NTC resistor paths 11. Each NTC resistor path 11 is equipped with a control switch 111 and an NTC resistor R1. The temperature detection unit 12 detects the temperature of each NTC resistor R1, and the main control chip 13 switches the NTC resistor path 11 on or off according to the temperature detection signal. This enables the circuit to disconnect the corresponding path when the temperature of the NTC resistor R1 is too high, and to turn on the path corresponding to the NTC resistor R1 with a lower temperature. This solves the problem that the NTC resistor R1 heats up after long-term operation, and the resistance decreases when restarting due to the high temperature, which reduces the ability to suppress surge current and prevents it from starting up quickly.

[0050] Power supply circuit example:

[0051] In this embodiment, the power supply circuit includes a surge protection circuit, which applies the surge protection circuit described in the above embodiment.

[0052] Example of household appliances:

[0053] Household appliances include power supply circuits, which utilize the power supply circuits described in the above embodiments. Household appliances include air conditioners, washing machines, televisions, fans, range hoods, air purifiers, humidifiers, dehumidifiers, and other similar appliances.

[0054] It should be noted that the above are only preferred embodiments of the present utility model, but the design concept of the utility model is not limited thereto. Any non-substantial modifications made to the present utility model using this concept shall also fall within the protection scope of the present utility model.

Claims

1. An NTC resistance protection circuit, characterized by: It includes at least two NTC resistor paths, a first power input terminal, a first power output terminal, a temperature detection unit, and a main control chip; At least two of the NTC resistor paths are connected in parallel between the first power input terminal and the first power output terminal; Each NTC resistor path includes a control switch and an NTC resistor. The control switch and the NTC resistor are connected in series between the first power input terminal and the first power output terminal. The control terminal of the control switch is electrically connected to the main control chip. The temperature detection unit is electrically connected to the main control chip; The temperature detection unit is used to detect the temperature of the NTC resistor in each NTC resistor path and send a temperature detection signal to the main control chip. The main control chip is used to switch the NTC resistor paths on or off according to the temperature detection signal.

2. The NTC resistor protection circuit according to claim 1, characterized in that: The temperature detection unit includes temperature sensing elements equal in number to the NTC resistors. Each temperature sensing element detects the temperature of one NTC resistor, and each temperature sensing element is electrically connected to the main control chip.

3. The NTC resistor protection circuit according to claim 2, characterized in that: The temperature sensing element includes a temperature sensor or a thermistor.

4. The NTC resistor protection circuit according to any one of claims 1 to 3, characterized in that: The first end of the control switch is electrically connected to the first power input terminal, the second end of the control switch is electrically connected to the first end of the NTC resistor, and the second end of the NTC resistor is electrically connected to the first power output terminal.

5. The NTC resistor protection circuit according to claim 4, characterized in that: The control switch is a single-pole single-throw relay switch.

6. The NTC resistor protection circuit according to claim 5, characterized in that: The first switch terminal of the single-pole single-throw relay switch is electrically connected to the first power input terminal, the second switch terminal of the single-pole single-throw relay switch is electrically connected to the first terminal of the NTC resistor, the first electromagnetic terminal of the single-pole single-throw relay switch is electrically connected to the power supply terminal, and the first electromagnetic terminal of the single-pole single-throw relay switch is electrically connected to the main control chip.

7. The NTC resistor protection circuit according to claim 4, characterized in that: The control switch is a switching transistor.

8. The NTC resistor protection circuit according to claim 7, characterized in that: The first terminal of the switching transistor is electrically connected to the first power input terminal, the second terminal of the switching transistor is electrically connected to the first terminal of the NTC resistor, and the control terminal of the switching transistor is electrically connected to the main control chip.

9. A surge protection circuit, comprising an NTC resistor protection circuit, an energy storage capacitor, a first terminal, a second terminal, a first load output terminal, and a second load output terminal, wherein the first terminal is electrically connected to the first load output terminal, the second terminal is electrically connected to the second load output terminal, the energy storage capacitor is connected in parallel between the first load output terminal and the second load output terminal, and the NTC resistor protection circuit is connected in series between the first terminal of the energy storage capacitor and the first terminal or between the second terminal of the energy storage capacitor and the second terminal. Its features are: The NTC resistor protection circuit uses the NTC resistor protection circuit described in any one of claims 1 to 8.

10. A power supply circuit comprising a surge protection circuit, characterized by: The surge protection circuit uses the surge protection circuit described in claim 9.

11. An electric household appliance comprising a power supply circuit, characterized by: The power supply circuit uses the power supply circuit described in claim 10.

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