Alternating current input detection circuit, alternating current input detection board and water heater

Abstract

The utility model discloses an alternating current input detection circuit, an alternating current input detection board and a water heater, the alternating current input detection circuit comprises an alternating current access end, an alternating current detection circuit and a main control circuit, the alternating current detection circuit is electrically connected with the alternating current access end, the signal end of the main control circuit is electrically connected with the alternating current detection circuit, and the signal end of the main control circuit is electrically connected with the alternating current input end. Alternating current is accessed through the alternating current access end, parameters of the alternating current are detected through the alternating current detection circuit, corresponding alternating current parameter detection signals are output, and finally the parameters of the alternating current are determined according to the alternating current parameter detection signals. Therefore, according to the utility model, parameters of the alternating current can be detected, and the equipment can be correspondingly controlled through the main control circuit, so that the equipment can be suitable for being used in different regions or under the condition of voltage variation, and the high efficiency and accuracy of alternating current detection and control based on the alternating current are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of alternating current collection and control, in particular to an alternating current input detection circuit, an alternating current input detection board and a water heater. Background Art

[0002] There are differences in voltage standards among countries and regions in the world. For example, China's voltage standard is 220V / 50Hz, the United States' voltage standard is 120V / 60Hz, and Europe's voltage standard is 230V / 50Hz. The voltage may change during use. In the prior art, when equipment is used in different regions or the voltage changes, it is necessary to query the voltage standard of the corresponding region or understand the voltage change in advance, and it is necessary to manually adjust the control circuit corresponding to the voltage and frequency. The operation is complicated and inefficient, and it is easy to cause batch accidents due to operational errors. Utility Model Content

[0003] The main purpose of the utility model is to provide an alternating current input detection circuit, aiming to improve the efficiency and accuracy of alternating current detection and control based on alternating current.

[0004] To achieve the above object, the utility model provides an AC input detection circuit, which is applied to a water heater. The AC input detection circuit includes:

[0005] An alternating current power access terminal, the alternating current power access terminal being used to access alternating current;

[0006] an alternating current detection circuit, the alternating current detection circuit being electrically connected to the alternating current access terminal; the alternating current detection circuit being used to detect parameters of the alternating current and output a corresponding alternating current parameter detection signal; and

[0007] A main control circuit, wherein a signal end of the main control circuit is electrically connected to the alternating current detection circuit; the main control circuit is used to determine the parameters of the alternating current according to the alternating current parameter detection signal.

[0008] Optionally, the parameters of the alternating current include at least one of an alternating current frequency and an alternating current voltage.

[0009] Optionally, the AC power access terminal has a first AC input terminal and a second AC input terminal; and the AC power detection circuit includes:

[0010] An optocoupler detection circuit, wherein the first input end of the optocoupler detection circuit is connected to the first AC input end, the second input end of the optocoupler detection circuit is connected to the second AC input end, the first output end of the optocoupler detection circuit is connected to the signal end of the main control circuit, and the second output end of the optocoupler detection circuit is grounded.

[0011] Optionally, the AC detection circuit further includes:

[0012] A power supply terminal and a first resistor, wherein a first end of the first resistor is connected to the power supply terminal, and a second end of the first resistor is connected to a common end of the main control circuit and the optical coupler detection circuit.

[0013] Optionally, the AC detection circuit further includes:

[0014] A rectifier circuit, wherein the input end of the rectifier circuit is connected to the first AC input end, and the output end of the rectifier circuit is connected to the first input end of the optocoupler detection circuit.

[0015] Optionally, the rectifier circuit includes: a first diode; an anode of the first diode is connected to the first AC input terminal; and a cathode of the first diode is connected to the first input terminal of the optocoupler detection circuit.

[0016] Optionally, the AC detection circuit further includes:

[0017] A voltage clamping circuit, wherein a first end of the voltage clamping circuit is connected to a first input end of the optocoupler detection circuit, and a second end of the voltage clamping circuit is connected to a second input end of the optocoupler detection circuit;

[0018] The voltage clamping circuit is used to limit the voltage between the first input terminal and the second input terminal of the optocoupler detection circuit to below a preset voltage.

[0019] Optionally, the voltage clamping circuit comprises:

[0020] A second diode; an anode of the second diode is connected to the second input end of the optocoupler detection circuit, and a cathode of the second diode is connected to the first input end of the optocoupler detection circuit.

[0021] Optionally, the AC detection circuit further includes:

[0022] A filter circuit is connected to the signal end of the main control circuit; the filter circuit is used to filter and process the AC power parameter detection signal before outputting it.

[0023] Optionally, the filtering circuit includes:

[0024] a second resistor, wherein a first end of the second resistor is connected to the signal end of the main control circuit, and a second end of the second resistor is connected to the first output end of the alternating current detection circuit;

[0025] A filter capacitor, wherein a first end of the filter capacitor is connected to the signal end of the main control circuit, and a second end of the filter capacitor is grounded.

[0026] The utility model also provides an AC input detection board, which includes the AC input detection circuit.

[0027] The utility model also provides a water heater, the water heater comprising the AC input detection board;

[0028] or,

[0029] The water heater comprises the AC power input detection circuit.

[0030] The utility model AC input detection circuit includes an AC access terminal, an AC detection circuit and a main control circuit. The AC detection circuit is electrically connected to the AC access terminal, and the signal terminal of the main control circuit is electrically connected to the AC detection circuit. AC is connected through the AC access terminal, and then the parameters of the AC are detected through the AC detection circuit, and a corresponding AC parameter detection signal is output. Finally, the parameters of the AC are determined according to the AC parameter detection signal. In this way, the utility model can detect the parameters of the AC, and can control the device accordingly through the main control circuit, so that the device can adapt to the use in different regions or under voltage changes, and improve the efficiency and accuracy of AC detection and control based on AC. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0032] Figure 1 It is a structural schematic diagram of an embodiment of an AC input detection circuit of the utility model;

[0033] Figure 2 It is a structural schematic diagram of another embodiment of the AC input detection circuit of the utility model;

[0034] Figure 3 It is a structural schematic diagram of another embodiment of the AC input detection circuit of the utility model;

[0035] Figure 4 It is a structural schematic diagram of another embodiment of the AC input detection circuit of the utility model;

[0036] Figure 5 This is a structural schematic diagram of another embodiment of the AC input detection circuit of the utility model;

[0037] Figure 6 It is a structural schematic diagram of another embodiment of the AC input detection circuit of the utility model;

[0038] Figure 7 It is a structural schematic diagram of another embodiment of the AC input detection circuit of the utility model;

[0039] Figure 8 It is a structural schematic diagram of another embodiment of the AC input detection circuit of the utility model;

[0040] Fig. 9 This is a structural schematic diagram of another embodiment of the AC input detection circuit of the utility model;

[0041] Fig.10 It is a structural schematic diagram of another embodiment of the AC input detection circuit of the utility model;

[0042] Fig.11 It is a waveform diagram of the AC power parameter detection signal of the utility model.

[0043] Description of Figure Numbers:

[0044] Label name Label name 10 AC power input terminal 20 AC detection circuit 30 Main control circuit 11 First AC input terminal 12 Second AC input terminal 21 Optocoupler detection circuit VCC Power supply R1 First resistor 22 Rectification circuit D1 The first diode 23 Voltage clamp circuit D2 The second diode 40 Filter circuit R2 Second resistor C1 Filter capacitor T1 AC cycle T2 Detection cycle

[0045] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0047] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0049] There are differences in voltage standards among countries and regions in the world. For example, China's voltage standard is 220V / 50Hz, the United States' voltage standard is 120V / 60Hz, and Europe's voltage standard is 230V / 50Hz. The voltage may change during use. In the prior art, when equipment is used in different regions or the voltage changes, it is necessary to query the voltage standard of the corresponding region or understand the voltage change in advance, and it is necessary to manually adjust the control circuit corresponding to the voltage and frequency. The operation is complicated and inefficient, and it is easy to cause batch accidents due to operational errors.

[0050] In order to solve the above problems, the utility model proposes an AC input detection circuit to improve the efficiency and accuracy of AC detection and control based on AC.

[0051] Reference Figure 1 In one embodiment of the utility model, the AC input detection circuit is applied to a water heater, and the AC input detection circuit includes:

[0052] An AC power input terminal 10 , an AC power detection circuit 20 and a main control circuit 30 .

[0053] The AC power input terminal 10 is used to input AC power.

[0054] The AC power detection circuit 20 is electrically connected to the AC power access terminal 10; the AC power detection circuit 20 is used to detect the parameters of the AC power and output a corresponding AC power parameter detection signal;

[0055] The signal end of the main control circuit 30 is electrically connected to the AC detection circuit 20; the main control circuit 30 is used to determine the parameters of the AC according to the AC parameter detection signal.

[0056] In this embodiment, since the working principles and circuit designs of various types of electrical equipment, especially household appliances, are generally designed based on the voltage standards of the area of ​​use, the set working parameters are adapted to the actual working parameters of the voltage in the area of ​​use. For example, when the electrical equipment is directly connected to the grid voltage of different countries and regions, or is connected to the voltage after voltage conversion by the local grid, or when the connected voltage changes due to external conditions, the actual working parameters of the electrical equipment may not match the set working parameters, thereby seriously affecting the working performance of the electrical equipment, damaging the electrical equipment, and even causing safety accidents.

[0057] Thus, the actual working parameters of the electric device after the voltage is connected can be detected in advance. If the actual working parameters of the electric device after the voltage is connected are compatible with the set working parameters, the user device can work normally under the connected voltage; if the actual working parameters of the electric device after the voltage is connected are not compatible with the set working parameters, the connected voltage is adjusted through the corresponding driving circuit to make the actual working voltage compatible with the set working voltage, or the working mode of the electric device is adjusted to adapt to the current connected voltage. The working parameters of the electric device can be working parameters such as rated current, rated voltage or rated frequency.

[0058] In this embodiment, AC power is connected through the AC power access terminal 10, and the parameters of the AC power are detected through the AC power detection circuit 20, and a corresponding AC power parameter detection signal is output. Finally, the parameters of the AC power are determined according to the AC power parameter detection signal by the main control circuit 30. By matching the parameters of the AC power with the preset parameters, it is possible to indirectly determine whether the actual working parameters of the electrical equipment are adapted to the rated working parameters. When the actual working parameters of the electrical equipment after the voltage is connected are not compatible with the set working parameters, the main control circuit 30 can output a corresponding control signal to control the corresponding drive circuit to adjust the connected voltage so that the actual working voltage is adapted to the set working voltage, or adjust the working mode of the electrical equipment to adapt to the currently connected voltage.

[0059] Optionally, see Figure 2 In an embodiment of the utility model, the main control circuit includes at least one of a processor such as a CPU, a DSP, and an MCU; the AC power access terminal 10 has a first AC input terminal 11 and a second AC input terminal 12, and the first AC input terminal 11 and the second AC input terminal 12 are used to output a live line voltage and a neutral line voltage, respectively.

[0060] It should be understood that in the embodiment of the present utility model, the AC power access terminal 10 can be directly connected to the grid voltage of various countries and regions, and the AC power access terminal 10 can also be connected to the voltage obtained by voltage conversion from the grid voltage of various countries and regions. It only needs to calculate the voltage parameters finally determined by the AC power detection circuit 20 and the main control circuit 30 in combination with the voltage conversion coefficient to determine the grid voltage before the voltage conversion.

[0061] Optionally, see Fig.11 In one embodiment of the present invention, the parameters of the alternating current include: at least one of the alternating current frequency and the alternating current voltage.

[0062] When only the AC frequency is detected, it is only necessary to determine the AC cycle T2, match the corresponding AC parameter detection signal output by the AC detection circuit 20 with the signal terminal level of the main control circuit 30, and when the AC cycle T2 is detected to be a preset cycle, the corresponding AC frequency can be obtained according to the relationship between the cycle and the frequency. In this way, the embodiment of the utility model can detect the AC frequency, and can control the device accordingly through the main control circuit, so that the device can adapt to the power grid frequency of different countries or regions or be used under the change of AC frequency.

[0063] When only detecting the AC voltage, it is only necessary to determine the ratio of the detection period T1 to the AC period T2, match the corresponding AC parameter detection signal output by the AC detection circuit 20 with the signal terminal level of the main control circuit 30, and when it is detected that the ratio of the detection period T1 of the AC parameter detection signal to the AC period T2 is within the preset ratio range, the corresponding AC voltage can be obtained. In this way, the embodiment of the utility model can detect the AC voltage, and can control the device accordingly through the main control circuit, so that the device can adapt to the voltage of different countries or regions or be used under the change of AC voltage.

[0064] It is understandable that the grid voltage generally has a certain allowable fluctuation range. When the voltage difference before and after the voltage change is small, and the voltage before and after the change are both within the allowable fluctuation range of the grid voltage, the electrical equipment can still be guaranteed to work normally under the preset working parameters. When the voltage difference between different countries or regions is small, and their voltages are within the allowable fluctuation range of each other's voltage, the preset ratio ranges corresponding to the two can be set to the same preset ratio range. When the electrical equipment works in the AC voltage corresponding to the detection period T1 of the AC parameter detection signal and the AC period T2 within the same preset ratio range, the electrical equipment can be guaranteed to work normally under the preset working parameters; in this way, the voltage detection in different regions with small voltage differences or small voltage changes can be completed through the same preset ratio range, so that the electrical equipment can work normally under the preset working parameters, making AC detection more convenient and saving AC detection time.

[0065] When detecting the AC voltage and the AC frequency at the same time, it is necessary to simultaneously determine the AC cycle T2 and the ratio of the detection cycle T1 to the AC cycle T2, and match the corresponding AC parameter detection signal output by the AC detection circuit 20 with the signal end level of the main control circuit 30. Similarly, the corresponding AC voltage and AC frequency can be obtained. In this way, the AC input detection circuit of the embodiment of the utility model includes an AC access terminal 10, an AC detection circuit 20 and a main control circuit 30, the AC detection circuit 20 is electrically connected to the AC access terminal 10, the signal end of the main control circuit 30 is electrically connected to the AC detection circuit 20, the AC is connected through the AC access terminal 10, and the parameters of the AC are detected by the AC detection circuit 20, and the corresponding AC parameter detection signal is output, and finally the parameters of the AC are determined according to the AC parameter detection signal. In this way, the utility model can detect the parameters of AC power and can control the device accordingly through the main control circuit 30, so that the device can adapt to use in different regions or under voltage changes, thereby improving the efficiency and accuracy of AC power detection and control based on AC power.

[0066] Optionally, see Figure 2 , Fig.10 In another embodiment of the present utility model, the AC detection circuit 20 includes:

[0067] The optocoupler detection circuit 21 has a first input terminal connected to the first AC input terminal 11, a second input terminal connected to the second AC input terminal 12, a first output terminal connected to the signal terminal of the main control circuit 30, and a second output terminal of the optocoupler detection circuit 21 is grounded.

[0068] In an embodiment of the present utility model, the optocoupler detection circuit 21 includes a light emitter and a light receiver, wherein the light emitter is an element for emitting light, and its first end is the first input end of the optocoupler detection circuit 21, and its second end is the second input end of the optocoupler detection circuit 21; the light receiver is an element for receiving light emitted by the light emitter to turn on the circuit, and its first end is the first output end of the optocoupler detection circuit 21, and its second end is the second output end of the optocoupler detection circuit 21.

[0069] Optionally, the optocoupler detection circuit 21 can also directly use an optocoupler chip. Through the optocoupler detection circuit 21, it is possible to complete the acquisition of a higher grid voltage and convert the sinusoidal AC signal into a low-voltage square wave signal that can be collected by the main control circuit. At the same time, the optocoupler detection circuit 21 realizes the photoelectric isolation between the AC power access terminal 10 and the signal terminal of the main control circuit 30, improves the anti-interference ability of the AC input detection circuit, and thus improves the accuracy of AC detection.

[0070] As an optional solution but not a limitation, in this embodiment, the first cycle is preset to be 20ms, and the second cycle is preset to be 16.67ms. When only the AC frequency is detected, it is only necessary to determine the AC cycle T2, and the corresponding AC parameter detection signal output by the AC detection circuit 20 is matched with the signal terminal level of the main control circuit 30. When the AC cycle T2 is detected to be 20ms, according to the relationship between the cycle and the frequency f=1 / T, the corresponding AC frequency can be obtained as 50Hz. Similarly, when the AC cycle T2 is detected to be 16.67ms, the corresponding AC frequency can be obtained as 60Hz. In this way, the embodiment of the utility model can detect the AC frequency, and can control the device accordingly through the main control circuit, so that the device can adapt to the power grid frequency of different countries or regions or be used under the change of AC frequency.

[0071] As an optional solution but not a limitation, in this embodiment, the on-voltage of the optocoupler detection circuit 21 is 13V, the first preset ratio range is 48.65%-48.69%, the second preset ratio range is 48.68-48.83%, the third preset ratio range is 49.32-49.37%, and the fourth preset ratio range is 49.35%-49.40%. When only the AC voltage is detected, it is only necessary to determine the ratio of the detection period T1 to the AC period T2, and match the corresponding AC parameter detection signal output by the AC detection circuit 20 with the signal end level of the main control circuit 30. When it is detected that the ratio of the detection period T1 of the AC parameter detection signal to the AC period T2 is 48.5 When the ratio of the detection period T1 of the AC parameter detection signal to the AC period T2 is within the range of 8%-48.69%, the corresponding AC voltage is 110V. When the ratio of the detection period T1 of the AC parameter detection signal to the AC period T2 is within the range of 48.68%-48.83%, the corresponding AC voltage is 120V. When the ratio of the detection period T1 of the AC parameter detection signal to the AC period T2 is within the range of 49.32%-49.37%, the corresponding AC voltage is 220V. When the ratio of the detection period T1 of the AC parameter detection signal to the AC period T2 is within the range of 49.35%-49.40%, the corresponding AC voltage is 230V. In this way, the embodiment of the utility model can detect the AC voltage and can control the device accordingly through the main control circuit, so that the device can adapt to the voltage of different countries or regions or be used under the change of AC voltage.

[0072] It can be understood that when the allowable fluctuation range of the grid voltage is +7% to -10%, the 220V grid voltage and the 230V grid voltage are within the allowable fluctuation range of each other's voltage, so the above-mentioned preset third ratio range and the preset fourth ratio range can be set to the same preset ratio range, so the above-mentioned preset second ratio range and the preset third ratio range can be set to the same preset ratio range of 49.32%-49.40%, when the electrical equipment operates under the AC voltage corresponding to the ratio of the detection period T1 of the AC parameter detection signal to the AC period T2 within the range of 49.32%-49.40%, it can be ensured that the electrical equipment works normally while meeting the preset working parameters; in this way, voltage detection in different regions with small voltage differences or under small voltage fluctuations can be completed through the same preset ratio range, so that the electrical equipment works normally while meeting the preset working parameters, making AC detection more convenient and saving AC detection time.

[0073] Optionally, the AC power detection circuit 20 can also use an isolation transformer to perform voltage conversion through the isolation transformer to realize the collection of AC power parameters and output corresponding AC power parameter detection signals. After the main control circuit 30 determines the AC power parameters, it calculates the AC power parameters based on the isolation transformer coefficients to complete the detection of the AC power parameters.

[0074] Optionally, in another embodiment of the present utility model, the AC detection circuit 20 further includes:

[0075] A power supply terminal VCC and a first resistor R1 , a first end of the first resistor R1 is connected to the power supply terminal VCC, and a second end of the first resistor R1 is connected to a common end of the main control circuit 30 and the optical coupler detection circuit 21 .

[0076] In this embodiment, the power supply terminal VCC is an external DC voltage, which can also be a DC voltage after rectification and voltage reduction of the AC power connected to the AC power access terminal 10. The first resistor R1 is a pull-up resistor, which is used to pull up the signal end level of the main control circuit 30, so that the optical coupler detection circuit 21 can generate an AC parameter detection signal in the form of a square wave based on the AC power to match the signal end level of the main control circuit 30, thereby completing the AC power detection.

[0077] Optionally, refer to Figure 4 In yet another embodiment of the present utility model, the AC detection circuit 20 further includes:

[0078] The rectifier circuit 22 has an input end connected to the first AC input end 11, and an output end connected to the first input end of the optocoupler detection circuit 21; the rectifier circuit 22 rectifies the AC power into DC power, so as to adapt to the optocoupler detection circuit 21, thereby preventing the optocoupler detection circuit 21 from being affected by the AC power's excessively high frequency, large amplitude variation, and positive and negative half-cycle characteristics, thereby affecting the accuracy of the AC power detection.

[0079] Optionally, refer to Figure 5 In another embodiment of the utility model, the rectifier circuit 22 includes: a first diode D1; an anode of the first diode D1 is connected to the first AC input terminal 11; a cathode of the first diode D1 is connected to the first input terminal of the optocoupler detection circuit 21; the first diode D1 can realize unidirectional conduction of AC power, thereby rectifying the AC power into pulsed DC power, thereby adapting to the normal operation of the optocoupler detection circuit 21.

[0080] Optionally, refer to Figure 6 In another embodiment of the present invention, the AC detection circuit 20 further includes:

[0081] A voltage clamping circuit 23, wherein a first end of the voltage clamping circuit 23 is connected to a first input end of the optocoupler detection circuit 21, and a second end of the voltage clamping circuit 23 is connected to a second input end of the optocoupler detection circuit 21; the voltage clamping circuit 23 is used to limit the voltage between the first input end and the second input end of the optocoupler detection circuit 21 to below a preset voltage.

[0082] Optionally, refer to Figure 7 In yet another embodiment of the present invention, the voltage clamping circuit 23 comprises:

[0083] The second diode D2; the anode of the second diode D2 is connected to the second input terminal of the optocoupler detection circuit 21, and the cathode of the second diode D2 is connected to the first input terminal of the optocoupler detection circuit 21, and is used to limit the voltage between the first input terminal and the second input terminal of the optocoupler detection circuit 21 to below a preset voltage, thereby protecting the optocoupler detection circuit 21.

[0084] Optionally, refer to Figure 8 In another embodiment of the present invention, the AC detection circuit 20 includes a first diode D1 and a second diode D2, wherein the anode of the first diode D1 is connected to the first AC input terminal 11; the cathode of the first diode D1 is connected to the first input terminal of the optocoupler detection circuit 21, the anode of the second diode D2 is connected to the second input terminal of the optocoupler detection circuit 21, and the cathode of the second diode D2 is connected to the first input terminal of the optocoupler detection circuit 21. By providing the first diode D1 and the second diode D2, dual protection of the optocoupler detection circuit 21 can be achieved, thereby improving the safety and accuracy of the AC detection circuit 20.

[0085] Optionally, refer to Fig. 9 , the AC detection circuit 20 further includes:

[0086] The filter circuit 40 is connected to the signal end of the main control circuit 30 ; the filter circuit 40 is used for filtering the AC power parameter detection signal and then outputting it.

[0087] Optionally, refer to Fig.10 , the filter circuit 40 comprises:

[0088] A second resistor R2, wherein a first end of the second resistor R2 is connected to a signal end of the main control circuit 30, and a second end of the second resistor R2 is connected to a first output end of the AC detection circuit 20;

[0089] The filter capacitor C1 has a first end connected to the signal end of the main control circuit 30 and a second end connected to the ground.

[0090] The second resistor R2 and the filter capacitor C1 can filter the AC power parameter detection signal, thereby improving the anti-interference capability of the AC power input detection circuit and thus improving the accuracy of the AC power input detection circuit in detecting AC power.

[0091] refer to Fig.10 The AC input detection circuit of the embodiment of the utility model includes an AC power access terminal 10 to access AC power, and uses the unidirectional conduction characteristic of the first diode D1 to rectify the AC power into a pulsed DC power input to the optocoupler detection circuit 21 to ensure the normal operation of the optocoupler detection circuit, and limits the voltage between the first input terminal and the second input terminal of the optocoupler detection circuit 21 to below a preset voltage through the second diode D2 to protect the optocoupler detection circuit 21. At the same time, the power supply terminal VCC inputs an external DC voltage, and uses the first resistor R1 to pull up the common terminal level of the optocoupler detection circuit 21 and the main control circuit 30, so that the optocoupler detection circuit 21 generates an AC parameter detection signal in the form of a square wave based on the AC power, and uses the second resistor R2 and the filter capacitor C1 to filter the AC parameter detection signal to improve the anti-interference ability of the AC input detection circuit, and finally matches the AC parameter detection signal with the signal terminal level of the main control circuit 30, thereby completing the parameter detection of the AC power.

[0092] In this way, since the structure of the AC input detection circuit is simple, the utility model can detect the parameters of AC power at a relatively low cost, and the optocoupler detection circuit 21 realizes the photoelectric isolation between the AC power access terminal 10 and the signal terminal of the main control circuit 30. Combined with the filter circuit 40, the anti-interference ability of the AC input detection circuit is improved, thereby improving the accuracy of AC power detection, and the main control circuit 30 can indirectly determine whether the actual working parameters of the electrical equipment are adapted to the rated working parameters by matching the parameters of AC power with the preset parameters. When the actual working parameters of the electrical equipment after the voltage is connected are not compatible with the set working parameters, the main control circuit 30 can directly output the corresponding control signal to control the corresponding drive circuit to adjust the connected voltage so that the actual working voltage is adapted to the set working voltage, or adjust the working mode of the electrical equipment to adapt to the currently connected voltage, so that the electrical equipment can be adapted to use in different regions or under voltage changes, thereby improving the efficiency and accuracy of AC power detection and control based on AC power.

[0093] The utility model also proposes an AC input detection board, which includes an AC input detection circuit. The specific structure of the AC input detection circuit refers to the above embodiment. Since the AC input detection circuit adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0094] The utility model also proposes a water heater, including an AC input detection board, or the water heater includes the AC input detection circuit. The specific structures of the AC input detection circuit and the AC input detection board refer to the above-mentioned embodiments. Since the AC input detection circuit adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0095] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An AC input detection circuit, applied to a water heater, characterized in that: The AC input detection circuit comprises: An alternating current power access terminal, the alternating current power access terminal being used to access alternating current; an alternating current detection circuit, the alternating current detection circuit being electrically connected to the alternating current access terminal; the alternating current detection circuit being used to detect parameters of the alternating current and output a corresponding alternating current parameter detection signal; and A main control circuit, wherein a signal end of the main control circuit is electrically connected to the alternating current detection circuit; the main control circuit is used to determine the parameters of the alternating current according to the alternating current parameter detection signal.

2. The AC input detection circuit according to claim 1, characterized in that: The parameters of the alternating current include at least one of an alternating current frequency and an alternating current voltage.

3. The AC input detection circuit according to claim 1, characterized in that: The AC power access terminal has a first AC input terminal and a second AC input terminal; the AC power detection circuit includes: An optocoupler detection circuit, wherein the first input end of the optocoupler detection circuit is connected to the first AC input end, the second input end of the optocoupler detection circuit is connected to the second AC input end, the first output end of the optocoupler detection circuit is connected to the signal end of the main control circuit, and the second output end of the optocoupler detection circuit is grounded.

4. The AC input detection circuit according to claim 3, characterized in that: The AC detection circuit also includes: A power supply terminal and a first resistor, wherein a first end of the first resistor is connected to the power supply terminal, and a second end of the first resistor is connected to a common end of the main control circuit and the optical coupler detection circuit.

5. The AC input detection circuit as claimed in claim 3, characterized in that: The AC detection circuit also includes: A rectifier circuit, wherein the input end of the rectifier circuit is connected to the first AC input end, and the output end of the rectifier circuit is connected to the first input end of the optocoupler detection circuit.

6. The AC input detection circuit as claimed in claim 5, characterized in that: The rectifier circuit includes: a first diode; an anode of the first diode is connected to the first AC input terminal; and a cathode of the first diode is connected to the first input terminal of the optocoupler detection circuit.

7. The AC input detection circuit according to claim 3, characterized in that: The AC detection circuit also includes: A voltage clamping circuit, wherein a first end of the voltage clamping circuit is connected to a first input end of the optocoupler detection circuit, and a second end of the voltage clamping circuit is connected to a second input end of the optocoupler detection circuit; The voltage clamping circuit is used to limit the voltage between the first input terminal and the second input terminal of the optocoupler detection circuit to below a preset voltage.

8. The AC input detection circuit according to claim 7, characterized in that: The voltage clamping circuit comprises: A second diode; an anode of the second diode is connected to the second input terminal of the optocoupler detection circuit, and a cathode of the second diode is connected to the first input terminal of the optocoupler detection circuit.

9. The AC input detection circuit according to any one of claims 1 to 8, characterized in that: The AC detection circuit also includes: A filter circuit is connected to the signal end of the main control circuit; the filter circuit is used to filter and process the AC power parameter detection signal before outputting it.

10. The AC input detection circuit according to claim 9, characterized in that: The filtering circuit comprises: a second resistor, wherein a first end of the second resistor is connected to the signal end of the main control circuit, and a second end of the second resistor is connected to the first output end of the alternating current detection circuit; A filter capacitor, wherein a first end of the filter capacitor is connected to the signal end of the main control circuit, and a second end of the filter capacitor is grounded.

11. An AC input detection board, characterized in that: The AC input detection board comprises the AC input detection circuit as described in any one of claims 1-10.

12. A water heater, characterized in that: The water heater comprises the AC input detection board as claimed in claim 11; or, The water heater comprises the AC input detection circuit as described in any one of claims 1-10.

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