Alternating current phase and impedance detection circuit

Abstract

The embodiment of the utility model provides an alternating current phase and impedance detection circuit which can judge the phase of alternating current based on a signal output by a first comparison module and control one of a first voltage division module and a second voltage division module to realize voltage division based on the signal output by the first comparison module. A first impedance branch circuit or a second impedance branch circuit is further formed, the voltage of a second clamp voltage end in the first impedance branch circuit is compared with a preset threshold value through a second comparison module, or the voltage of a first clamp voltage end in the second impedance branch circuit is compared with the preset threshold value, and the magnitude of the current alternating current impedance is judged through a signal output by the second comparison module. Therefore, two sets of circuits do not need to be specially designed to respectively detect the phase and impedance of the alternating current, the complexity of the circuit structure is reduced, and the chip area is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of integrated circuits, in particular to an alternating current phase and impedance detection circuit. Background Art

[0002] At present, the mains electricity usually needs to be rectified before it can be used to supply power to electrical equipment. In order to be able to drive the electrical equipment normally, it is generally necessary to detect the power supply status of the mains electricity first. In some specific application scenarios, it is necessary not only to detect the phase of the AC power, but also to detect the impedance information of the AC power. In the existing technology, different circuits are generally used to achieve detection separately. Obviously, this detection method will lead to problems such as complex circuit structure and large chip area. Utility Model Content

[0003] The purpose of the embodiment of the utility model is to provide an AC phase and impedance detection circuit to solve the above problems. The embodiment of the utility model achieves the above purpose through the following technical solutions.

[0004] The embodiment of the utility model provides an AC phase and impedance detection circuit, comprising: a first connection end and a second connection end for connecting to the neutral and live wires; a first clamping module, wherein the first clamping end of the first clamping module is connected to the first connection end; a second clamping module, wherein the second clamping end of the second clamping module is connected to the second connection end; a first comparison module, which compares a signal representing the voltage of the first clamping end and a signal representing the voltage of the second clamping end with a preset voltage, and outputs a signal representing the phase information of the AC power; a first voltage dividing module connected to the first clamping end, and a second voltage dividing module connected to the second clamping end; a control module, which is respectively connected to the output end of the first comparison module, the controlled end of the first voltage dividing module, and the controlled end of the second voltage dividing module; controlled by the control module, the first clamping module, the AC impedance of the AC power, and the second voltage dividing module form a first impedance branch, or the second clamping module, the AC impedance, and the first voltage dividing module form a second impedance branch; a second comparison module, which compares the signal representing the voltage of the first clamping end and the signal representing the voltage of the second clamping end with a preset threshold, and outputs a signal representing the AC impedance information.

[0005] In some embodiments, the AC power phase and impedance detection circuit further includes: a first resistor connected between the first connection terminal and the first clamping terminal; and a second resistor connected between the second connection terminal and the second clamping terminal.

[0006] In some embodiments, the first resistor and the second resistor have the same resistance value.

[0007] In some embodiments, the first voltage divider module includes a first switch tube and a third resistor connected in series, and the controlled end of the first switch tube serves as the controlled end of the first voltage divider module; the second voltage divider module includes a second switch tube and a fourth resistor connected in series, and the controlled end of the second switch tube serves as the controlled end of the second voltage divider module.

[0008] In some embodiments, the third resistor and the fourth resistor have the same resistance value.

[0009] In some embodiments, the clamping range of the first clamping module and the second clamping module is from a first voltage to a second voltage, and the first voltage is greater than the second voltage.

[0010] In some embodiments, the first clamping module includes a third switch tube and a fourth switch tube, the first end of the third switch tube and the first end of the fourth switch tube are connected to the power supply voltage end, the second end of the third switch tube is connected to the power supply voltage end, the third end of the third switch tube and the second end of the fourth switch tube are connected to the first clamping end, and the third end of the fourth switch tube is connected to the reference ground end.

[0011] In some embodiments, the first clamping module also includes: a first unidirectional switch tube, connected between the power supply voltage end and the second end of the third switch tube, and the conduction direction of the first unidirectional switch tube is from the power supply voltage end to the second end of the third switch tube; a second unidirectional switch tube, connected between the third end of the fourth switch tube and the reference ground end; the conduction direction of the second unidirectional switch tube is from the third end of the fourth switch tube to the reference ground end.

[0012] In some embodiments, the third switch tube is an NMOS transistor, and the fourth switch tube is a PMOS transistor.

[0013] In some embodiments, the first comparison module includes a first comparison unit and a second comparison unit; the first input end of the first comparison unit is connected to the first clamping end, the first input end of the second comparison unit is connected to the second clamping end, and the second input end of the first comparison unit and the second input end of the second comparison unit are connected to the first reference end;

[0014] And / or, the second comparison module includes a third comparison unit and a fourth comparison unit; the first input end of the third comparison unit is connected to the first clamping end, the first input end of the fourth comparison unit is connected to the second clamping end, and the second input end of the third comparison unit and the second input end of the fourth comparison unit are connected to the second reference end.

[0015] The AC phase and impedance detection circuit provided in this embodiment can determine the phase of the AC based on the signal output by the first comparison module, and control one of the first voltage divider module and the second voltage divider module to achieve voltage division based on the signal output by the first comparison module, thereby forming a first impedance branch or a second impedance branch. The voltage of the second clamping end in the first impedance branch is compared with a preset threshold value through the second comparison module, or the voltage of the first clamping end in the second impedance branch is compared with a preset threshold value. The signal output by the second comparison module determines the size of the AC impedance at this time. Therefore, there is no need to specially design two sets of circuits to detect the phase and impedance of the AC respectively. At the same time, it is also suitable for detecting the situation where the live wire and the neutral wire are connected reversely, which reduces the complexity of the circuit structure and reduces the chip area. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments of the utility model will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 is a schematic diagram of a module of the AC phase and impedance detection circuit provided in this embodiment;

[0018] Figure 2 Schematic diagram of a circuit structure of an AC phase and impedance detection circuit provided in this embodiment. DETAILED DESCRIPTION

[0019] 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 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.

[0020] like Figure 1As shown, this embodiment provides an AC phase and impedance detection circuit, which includes: a first connection terminal A and a second connection terminal B for connecting to the neutral and live wires; a first clamping module 11, wherein the first clamping terminal M of the first clamping module 11 is connected to the first connection terminal A; a second clamping module 12, wherein the second clamping terminal N of the second clamping module 12 is connected to the second connection terminal B; a first comparison module 13 compares a signal representing a voltage at the first clamping terminal M and a signal representing a voltage at the second clamping terminal N with a preset voltage, and outputs a signal representing AC phase information; a first voltage divider module 15 connected to the first clamping terminal M and a second voltage divider module 16 connected to the second clamping terminal N; A second voltage-dividing module 16 connected to the voltage terminal N; a control module 14, which is respectively connected to the output end of the first comparison module 13, the controlled end of the first voltage-dividing module 15, and the controlled end of the second voltage-dividing module 16; controlled by the control module 14, the first clamping module 11, the AC impedance Rac of the AC power, and the second voltage-dividing module 16 form a first impedance branch, or the second clamping module 12, the AC impedance Rac, and the first voltage-dividing module 15 form a second impedance branch; a second comparison module 17, compares the signal representing the voltage of the first clamping terminal M and the signal representing the voltage of the second clamping terminal N with a preset threshold value, and outputs a signal representing the information of the AC impedance Rac.

[0021] In this embodiment, the first connection terminal A can be connected to either the live wire or the neutral wire, and the second connection terminal B can be connected to the other of the live wire and the neutral wire. The AC phase and impedance detection circuit provided in this embodiment is applicable to the case where the live wire and the neutral wire are reversely connected.

[0022] In this embodiment, the first clamping module 11 can limit the voltage of the first clamping terminal M to a first preset range, and the second clamping module 12 can limit the voltage of the second clamping terminal N to a second preset range. The first preset range and the second preset range can be set according to actual circuit requirements.

[0023] In this embodiment, the first comparison module 13 can be connected to the first clamping terminal M to obtain the voltage of the first clamping terminal M, which is equivalent to obtaining a signal representing the voltage of the first clamping terminal M, wherein the signal representing the voltage of the first clamping terminal M can be regarded as obtaining a signal representing the voltage of the first clamping terminal M. The first comparison module 13 can be connected to the second clamping terminal N to obtain the voltage of the second clamping terminal N, which is equivalent to obtaining a signal representing the voltage of the second clamping terminal N, wherein the signal representing the voltage of the second clamping terminal N can be regarded as obtaining a signal representing the voltage of the second clamping terminal N.

[0024] In addition, when the voltage difference between the voltage of the first connection terminal A and the voltage of the second connection terminal B is greater than the preset voltage difference, the first clamping module 11 can limit the voltage of the first clamping terminal M to the maximum value in the first preset range, and the second clamping module 12 can limit the voltage of the second clamping terminal N to the minimum value in the second preset range. When the voltage difference between the voltage of the second connection terminal B and the voltage of the first connection terminal A is greater than the preset voltage difference, the first clamping module 11 can limit the voltage of the first clamping terminal M to the minimum value in the first preset range, and the second clamping module 12 can limit the voltage of the second clamping terminal N to the maximum value in the second preset range.

[0025] It should be noted that the preset voltage may include a first preset voltage and a second preset voltage, and the first comparison module 13 compares the signal representing the voltage of the first clamping terminal M with the first preset voltage, and the first comparison module 13 compares the signal representing the voltage of the second clamping terminal N with the second preset voltage. The first preset voltage and the second preset voltage may be the same or different. Specifically, when the circuit structure of the first clamping module 11 is consistent with that of the second clamping module 12, the first preset voltage and the second preset voltage are consistent. When the circuit structure of the first clamping module 11 is inconsistent with that of the second clamping module 12, the first preset voltage and the second preset voltage are inconsistent.

[0026] In this embodiment, when detecting the phase of the alternating current, if the voltage of the first clamping terminal M is the maximum value in the first preset range and the voltage of the second clamping terminal N is the minimum value in the second preset range, the first comparison module 13 compares the voltage of the first clamping terminal M with the first preset voltage and the voltage of the second clamping terminal N with the second preset voltage. The signal output by the first comparison module 13 can represent the magnitude relationship between the voltage of the first clamping terminal M and the first preset voltage and the magnitude relationship between the voltage of the second clamping terminal N and the second preset voltage. When the signal output by the first comparison module 13 represents that the voltage of the first clamping terminal M is greater than the first preset voltage and the voltage of the second clamping terminal N is less than the second preset voltage, it indicates that the voltage difference between the voltage of the first connection terminal A and the voltage of the second connection terminal B is greater than the preset voltage. When the signal output by the first comparison module 13 represents that the voltage of the first clamping terminal M is less than the first preset voltage and the voltage of the second clamping terminal N is greater than the second preset voltage, it indicates that the voltage difference between the voltage of the second connection terminal B and the voltage of the first connection terminal A is greater than the preset voltage.

[0027] In this embodiment, the control module 14 can obtain the signal output by the first comparison module 13, and then determine the phase information of the alternating current connected to the first connection terminal A and the second connection terminal B.

[0028] When the control module 14 obtains that the voltage difference between the voltage of the first connection terminal A and the voltage of the second connection terminal B is less than the preset voltage difference, or the voltage difference between the voltage of the second connection terminal B and the voltage of the first connection terminal A is less than the preset voltage difference, the control module 14 can send a signal to the controlled end of the first voltage divider module 15 and the controlled end of the second voltage divider module 16 to control one of the first voltage divider module 15 and the second voltage divider module 16 to realize the voltage dividing function.

[0029] In this embodiment, the second comparison module 17 can be connected to the first clamping terminal M, or to the element in the first voltage dividing module 15 that actually has a voltage dividing function, and obtains the voltage of the first clamping terminal M, which is equivalent to obtaining a signal representing the voltage of the first clamping terminal M, wherein the signal representing the voltage of the first clamping terminal M can be regarded as obtaining a signal representing the voltage of the first clamping terminal M. The second comparison module 17 can be connected to the second clamping terminal N, or to the element in the first voltage dividing module 15 that actually has a voltage dividing function, and obtains the voltage of the second clamping terminal N, which is equivalent to obtaining a signal representing the voltage of the second clamping terminal N, wherein the signal representing the voltage of the second clamping terminal N can be regarded as obtaining a signal representing the voltage of the second clamping terminal N.

[0030] In this embodiment, the first clamping module 11, the AC impedance Rac of the AC power, and the second voltage divider module 16 are controlled by the control module 14 to form a first impedance branch, or the second clamping module 12, the AC impedance Rac, and the first voltage divider module 15 form a second impedance branch, which can be expressed as follows: at a certain moment, the control module 14 forms the first impedance branch or the second impedance branch by controlling the first voltage divider module 15 and the second voltage divider module 16. The second comparison module 17 can determine the current AC impedance Rac based on the voltage of the second clamping terminal N in the first impedance branch or the voltage of the first clamping terminal M in the second impedance branch, and is suitable for detecting the reverse connection of the live wire and the neutral wire.

[0031] It should be noted that the preset threshold may include a first preset threshold and a second preset threshold, and the second comparison module 17 compares the signal representing the voltage at the first clamping terminal M with the first preset threshold, and the second comparison module 17 compares the signal representing the voltage at the second clamping terminal N with the second preset threshold. The first preset threshold and the second preset threshold may be the same or different. Specifically, when the circuit structure of the first clamping module 11 is consistent with that of the second clamping module 12, and the circuit structure of the first voltage divider module 15 is consistent with that of the second voltage divider module 16, the first preset threshold and the second preset threshold are consistent. When the circuit structure of the first clamping module 11 is inconsistent with that of the second clamping module 12, and / or the circuit structure of the first voltage divider module 15 is inconsistent with that of the second voltage divider module 16, the first preset threshold and the second preset threshold are inconsistent.

[0032] Specifically, when the control module 14 controls the first voltage divider module 15 to realize the voltage divider function, at this time, the voltage of the first clamp terminal M is the minimum value of the first preset range, and the first clamp module 11, the AC impedance Rac, and the second voltage divider module 16 form a first impedance branch. At this time, the voltage of the second clamp terminal N is inversely proportional to the size of the AC impedance Rac, that is, the larger the voltage of the second clamp terminal N, the smaller the AC impedance Rac. The second comparison module 17 compares the voltage of the second clamp terminal N with the second preset threshold value. If the voltage of the second clamp terminal N is greater than the second preset threshold value, it indicates that the AC impedance Rac is small at this time. Therefore, when the signal output by the second comparison module 17 indicates that the voltage of the second clamp terminal N is greater than the second preset threshold value, it indicates that the AC impedance Rac is less than or equal to the preset AC impedance Rac threshold value.

[0033] In addition, when the control module 14 controls the second voltage divider module 16 to realize the voltage divider function, at this time, the voltage of the second clamping terminal N is the minimum value of the first preset range, and the second clamping module 12, the AC impedance Rac, and the first voltage divider module 15 form a second impedance branch. At this time, the voltage of the first clamping terminal M is inversely proportional to the size of the AC impedance Rac, that is, the larger the voltage of the first clamping terminal M, the smaller the AC impedance Rac. The second comparison module 17 compares the voltage of the first clamping terminal M with the first preset threshold value. If the voltage of the first clamping terminal M is greater than the first preset threshold value, it indicates that the AC impedance Rac is small at this time. Therefore, when the signal output by the second comparison module 17 indicates that the voltage of the first clamping terminal M is greater than the first preset threshold value, it indicates that the AC impedance Rac is less than or equal to the preset AC impedance Rac threshold value.

[0034] It can be seen from the above description that in the present embodiment, there is no specific restriction on the specific manner in which the first comparison module 13 and the second comparison module 17 obtain the signal representing the voltage of the first clamping terminal M and the signal representing the voltage of the second clamping terminal N. That is, those skilled in the art can adaptively configure the connection positions of the input terminals of the first comparison module 13 and the second comparison module 17, and the signals at the connection positions satisfy the conditions of following the changes of the voltage of the first clamping terminal M and the voltage of the second clamping terminal N.

[0035] Through the implementation of this embodiment, the phase of the alternating current can be determined based on the signal output by the first comparison module 13, and based on the signal output by the first comparison module 13, one of the first voltage divider module 15 and the second voltage divider module 16 can be controlled to achieve voltage division, thereby forming a first impedance branch or a second impedance branch. The voltage of the second clamping terminal N in the first impedance branch is compared with a preset threshold value through the second comparison module 17, or the voltage of the first clamping terminal M in the second impedance branch is compared with a preset threshold value. The signal output by the second comparison module 17 determines the size of the AC impedance Rac at this time. Therefore, there is no need to specially design two sets of circuits to detect the phase and impedance of the alternating current respectively. At the same time, it is also suitable for detecting the situation where the live wire and the neutral wire are connected in reverse, which reduces the complexity of the circuit structure and reduces the chip area.

[0036] In some embodiments, Figure 1 As shown, the AC phase and impedance detection circuit may further include: a first resistor R1 connected between the first connection terminal A and the first clamping terminal M; and a second resistor R2 connected between the second connection terminal B and the second clamping terminal N.

[0037] In this embodiment, the first resistor R1 may be a single resistor or a resistor element formed by connecting a plurality of resistors in series and / or in parallel, and the specific embodiment of the first resistor R1 is not specifically limited. The same applies to the following resistors.

[0038] In this embodiment, the first resistor R1 and the second resistor R2 can be regarded as current limiting resistors.

[0039] In some embodiments, the resistance values ​​of the first resistor R1 and the second resistor R2 may be the same.

[0040] In some embodiments, Figure 2 As shown, the first voltage-dividing module 15 may include a first switch tube M1 and a third resistor R3 connected in series, and the controlled end S1 of the first switch tube M1 serves as the controlled end of the first voltage-dividing module 15; the second voltage-dividing module 16 may include a second switch tube M2 and a fourth resistor R4 connected in series, and the controlled end S2 of the second switch tube M2 serves as the controlled end of the second voltage-dividing module 16.

[0041] In this embodiment, the first switch tube M1 is controlled by the control module 14, and the control module 14 controls the current to flow through the first switch tube M1 and the third resistor R3. The first switch tube M1 can be a triode, a field effect tube, etc. In actual application, the manufacturer can select the corresponding switch type according to the actual application requirements of the AC phase and the impedance detection circuit, and then determine the connection relationship of the switch. The following switch tubes are the same, and will not be repeated here.

[0042] In some embodiments, the first end of the first switch tube M1 serves as the controlled end S1 of the first switch tube M1 and the controlled end of the first voltage divider module 15. The first end of the first switch tube M1 is connected to the control module 14, the second end of the first switch tube M1 is connected to the first clamping end M, the third end of the first switch tube M1 is connected to the first end of the third resistor R3, and the second end of the third resistor R3 can be connected to the reference ground end. Alternatively, preferably, the second end of the first switch tube M1 can also be connected to the second end of the third resistor R3, the third end of the first switch tube M1 can also be connected to the reference ground end, and the first end of the third resistor R3 can be connected to the first clamping end M. When the control module 14 controls the first switch tube M1 to turn on, the third resistor R3 can play a voltage dividing role, and the second comparison module 17 can compare the voltage of the first clamping end M with the voltage of the second reference end Y based on the voltage dividing effect of the third resistor R3, and then determine the size of the current AC impedance Rac. Figure 2 As shown, the first switch tube M1 can be an NMOS transistor, the drain end of the NMOS transistor serves as the second end of the first switch tube M1, and the source end of the NMOS transistor serves as the third end of the first switch tube M1. When the NMOS transistor is turned on, the voltage across the third resistor R3 can be basically consistent with the voltage of the first clamping end M.

[0043] In some embodiments, the first end of the second switch tube M2 serves as the controlled end S2 of the second switch tube M2 and the controlled end of the second voltage divider module 16. The first end of the second switch tube M2 is connected to the control module 14, the second end of the second switch tube M2 is connected to the second clamping end N, the third end of the second switch tube M2 is connected to the first end of the fourth resistor R4, and the second end of the fourth resistor R4 can be connected to the reference ground end. Alternatively, preferably, the second end of the second switch tube M2 can also be connected to the second end of the fourth resistor R4, the third end of the second switch tube M2 can also be connected to the reference ground end, and the first end of the fourth resistor R4 can be connected to the second clamping end N. When the control module 14 controls the second switch tube M2 to turn on, the fourth resistor R4 can play a voltage dividing role, and the second comparison module 17 can compare the voltage of the second clamping end N with the voltage of the second reference end Y based on the voltage dividing effect of the fourth resistor R4, and then determine the size of the current AC impedance Rac. Figure 2 As shown, the second switch tube M2 can be an NMOS transistor, the drain end of the NMOS transistor serves as the second end of the second switch tube M2, and the source end of the NMOS transistor serves as the third end of the second switch tube M2. When the NMOS transistor is turned on, the voltage across the fourth resistor R4 can be basically consistent with the voltage of the second clamping end N.

[0044] In some embodiments, the input end of the second comparison module 17 can be connected to the first end of the third resistor R3 and the first end of the fourth resistor R4 respectively, so as to obtain a signal representing the voltage of the first clamping terminal M and a signal representing the voltage of the second clamping terminal N.

[0045] In some embodiments, the resistance values ​​of the third resistor R3 and the fourth resistor R4 may be the same.

[0046] In some embodiments, the clamping range of the first clamping module 11 and the second clamping module 12 is from a first voltage to a second voltage, and the first voltage is greater than the second voltage.

[0047] In some embodiments, the resistance values ​​of the first resistor R1 and the second resistor R2 may be the same, the resistance values ​​of the third resistor R3 and the fourth resistor R4 may be the same, and the clamping ranges of the first clamping module 11 and the second clamping module 12 are both from the first voltage to the second voltage, and the first voltage is greater than the second voltage. At this time, the preset voltage may be one, that is, the first preset voltage described in the above embodiment is the same as the second preset voltage. The preset threshold may be one, that is, the first preset threshold described in the above embodiment is the same as the second preset threshold.

[0048] In some embodiments, Figure 2 As shown, the first clamping module 11 may include a third switch tube M3 and a fourth switch tube M4, the first end of the third switch tube M3 and the first end of the fourth switch tube M4 are connected to the power supply voltage terminal VDD, the second end of the third switch tube M3 is connected to the power supply voltage terminal VDD, the third end of the third switch tube M3 and the second end of the fourth switch tube M4 are connected to the first clamping terminal M, and the third end of the fourth switch tube M4 is connected to the reference ground terminal.

[0049] In this embodiment, the third switch tube M3 may be an NMOS transistor, and the fourth switch tube M4 may be a PMOS transistor. The drain end of the NMOS transistor serves as the second end of the third switch tube M3, and the source end of the NMOS transistor serves as the third end of the third switch tube M3. The drain end of the PMOS transistor serves as the second end of the fourth switch tube M4, and the source end of the PMOS transistor serves as the third end of the fourth switch tube M4.

[0050] In this embodiment, during the detection of the AC impedance Rac, as the voltage of the first connection terminal A gradually increases, the voltage of the first clamping terminal M follows the increase and reaches the conduction condition of the fourth switch tube M4, so that the third switch tube M3 is turned off and the fourth switch tube M4 is turned on. At this time, the voltage of the first clamping terminal M is the first voltage. At this time, the first voltage is the sum of the voltage of the power supply voltage terminal VDD and the voltage drop of the fourth switch tube M4, and the maximum voltage of the first clamping terminal M is limited to the sum of the voltage of the power supply voltage terminal VDD and the voltage drop of the fourth switch tube M4. During the detection of the AC impedance Rac, as the voltage of the first connection terminal A gradually decreases, the voltage of the first clamping terminal M follows the decrease and reaches the conduction condition of the third switch tube M3, so that the fourth switch tube M4 is turned off and the third switch tube M3 is turned on. At this time, the voltage of the first clamping terminal M is the second voltage. At this time, the second voltage is the difference between the voltage of the power supply voltage terminal VDD and the voltage drop of the third switch tube M3, and the minimum voltage of the first clamping terminal M is limited to the difference between the voltage of the power supply voltage terminal VDD and the voltage drop of the third switch tube M3.

[0051] Therefore, through the above-mentioned third switch tube M3 and the fourth switch tube M4, the voltage range of the first clamping terminal M can be limited to the first voltage to the second voltage, and the voltage range of the first clamping terminal M is relatively close to the voltage of the power supply voltage terminal VDD. In the AC phase and impedance detection circuit, the voltage difference between the first comparison module 13, the second comparison module 17, the first voltage divider module 15, the second voltage divider module 16, the first clamping module 11, and the second clamping module 12 is small, reducing the difficulty of circuit design.

[0052] In some embodiments, Figure 2 As shown, the first clamping module 11 may also include: a first unidirectional switch tube N1, connected between the power supply voltage terminal VDD and the second end of the third switch tube M3, and the conduction direction of the first unidirectional switch tube N1 is from the power supply voltage terminal VDD to the second end of the third switch tube M3; a second unidirectional switch tube N2, connected between the third end of the fourth switch tube M4 and the reference ground terminal; and the conduction direction of the second unidirectional switch tube N2 is from the third end of the fourth switch tube M4 to the reference ground terminal.

[0053] In this embodiment, when the third switch tube M3 is turned on, the first unidirectional switch tube N1 is turned on synchronously; when the fourth switch tube M4 is turned on, the second unidirectional switch tube N2 is turned on synchronously. Figure 2 As shown, the first unidirectional switch tube N1 can be a PMOS transistor with a gate-source connection, and the second unidirectional switch tube N2 can be an NMOS transistor with a drain-gate connection. The PMOS transistor and the NMOS transistor can be regarded as diodes. In addition, the first unidirectional switch tube N1 and the second unidirectional switch tube N2 can be set as diodes.

[0054] In some embodiments, the third switch transistor M3 may be an NMOS transistor, and the fourth switch transistor M4 may be a PMOS transistor.

[0055] In some embodiments, Figure 2 As shown, the second clamping module 12 may include a fifth switch tube M5 and a sixth switch tube M6, the first end of the fifth switch tube M5 and the first end of the sixth switch tube M6 are connected to the power supply voltage terminal VDD, the second end of the fifth switch tube M5 is connected to the power supply voltage terminal VDD, the third end of the fifth switch tube M5 and the second end of the sixth switch tube M6 are connected to the second clamping terminal N, and the third end of the sixth switch tube M6 is connected to the reference ground terminal.

[0056] In this embodiment, the fifth switch tube M5 may be an NMOS transistor, and the sixth switch tube M6 may be a PMOS transistor. The drain end of the NMOS transistor serves as the second end of the fifth switch tube M5, and the source end of the NMOS transistor serves as the third end of the fifth switch tube M5. The drain end of the PMOS transistor serves as the second end of the sixth switch tube M6, and the source end of the PMOS transistor serves as the third end of the sixth switch tube M6.

[0057] In this embodiment, during the detection of the AC impedance Rac, as the voltage of the first connection terminal A gradually increases, the voltage of the second clamping terminal N follows the increase and reaches the conduction condition of the sixth switch tube M6, so that the fifth switch tube M5 is turned off and the sixth switch tube M6 is turned on. At this time, the voltage of the second clamping terminal N is the first voltage. At this time, the first voltage is the sum of the voltage of the power supply voltage terminal VDD and the voltage drop of the sixth switch tube M6, and the maximum voltage of the second clamping terminal N is limited to the sum of the voltage of the power supply voltage terminal VDD and the voltage drop of the sixth switch tube M6. During the detection of the AC impedance Rac, as the voltage of the first connection terminal A gradually decreases, the voltage of the second clamping terminal N follows the decrease and reaches the conduction condition of the fifth switch tube M5, so that the sixth switch tube M6 is turned off and the fifth switch tube M5 is turned on. At this time, the voltage of the second clamping terminal N is the second voltage. At this time, the second voltage is the difference between the voltage of the power supply voltage terminal VDD and the voltage drop of the fifth switch tube M5, and the minimum voltage of the second clamping terminal N is limited to the difference between the voltage of the power supply voltage terminal VDD and the voltage drop of the fifth switch tube M5.

[0058] Therefore, through the fifth switch tube M5 and the sixth switch tube M6, the voltage range of the second clamping terminal N can be limited to the first voltage to the second voltage, and the voltage range of the second clamping terminal N is relatively close to the voltage of the power supply voltage terminal VDD. In the AC phase and impedance detection circuit, the voltage difference between the first comparison module 13, the second comparison module 17, the first voltage divider module 15, the second voltage divider module 16, the first clamping module 11, and the second clamping module 12 is small, reducing the difficulty of circuit design.

[0059] In some embodiments, Figure 2 As shown, the second clamping module 12 may further include: a third unidirectional switch tube N3, connected between the power supply voltage terminal VDD and the second end of the fifth switch tube M5, and the conduction direction of the third unidirectional switch tube N3 is from the power supply voltage terminal VDD to the second end of the fifth switch tube M5; a fourth unidirectional switch tube N4, connected between the third end of the sixth switch tube M6 and the reference ground terminal; the conduction direction of the fourth unidirectional switch tube N4 is from the third end of the sixth switch tube M6 to the reference ground terminal.

[0060] In this embodiment, when the fifth switch tube M5 is turned on, the third unidirectional switch tube N3 is turned on synchronously; when the sixth switch tube M6 is turned on, the fourth unidirectional switch tube N4 is turned on synchronously. Figure 2 As shown, the third unidirectional switch tube N3 can be a PMOS transistor with a gate-source connection, and the fourth unidirectional switch tube N4 can be an NMOS transistor with a drain-gate connection. The PMOS transistor and the NMOS transistor can be regarded as diodes. In addition, the third unidirectional switch tube N3 and the fourth unidirectional switch tube N4 can be set as diodes.

[0061] In some embodiments, the fifth switch transistor M5 may be an NMOS transistor, and the sixth switch transistor M6 may be a PMOS transistor.

[0062] In some embodiments, the specification parameters of the first switch tube M1 and the second switch tube M2 are consistent, the specification parameters of the third switch tube M3 and the fifth switch tube M5 are consistent, the specification parameters of the fourth switch tube M4 and the sixth switch tube M6 are consistent, the specification parameters of the first unidirectional switch tube N1 and the third unidirectional switch tube N3 are consistent, and the specification parameters of the second unidirectional switch tube N2 and the fourth unidirectional switch tube N4 are consistent. That is, the circuit structure and relative connection relationship of the first voltage divider module 15 and the second voltage divider module 16, and the first clamping module 11 and the second clamping module 12 are consistent.

[0063] In some embodiments, the control module 14 may determine the phase information of the AC power based on the signal output by the first comparison module 13 at a certain moment, or may determine the phase information of the AC power based on the continuously changing signal output by the first comparison module 13 over a period of time.

[0064] In some embodiments, Figure 2 As shown, the first comparison module 13 may include a first comparison unit CMP1 and a second comparison unit CMP2; the first input terminal of the first comparison unit CMP1 is connected to the first clamping terminal M, the first input terminal of the second comparison unit CMP2 is connected to the second clamping terminal N, and the second input terminal of the first comparison unit CMP1 and the second input terminal of the second comparison unit CMP2 are connected to the first reference terminal X;

[0065] And / or, the second comparison module 17 may include a third comparison unit CMP3 and a fourth comparison unit CMP4; the first input terminal of the third comparison unit CMP3 is connected to the first clamping terminal M, the first input terminal of the fourth comparison unit CMP4 is connected to the second clamping terminal N, and the second input terminal of the third comparison unit CMP3 and the second input terminal of the fourth comparison unit CMP4 are connected to the second reference terminal Y.

[0066] In some embodiments, the signals outputted by the output terminals of the first comparison unit CMP1 and the second comparison unit CMP2 may represent the phase information of the alternating current, and the output terminals of the first comparison unit CMP1 and the second comparison unit CMP2 may also be connected to the control module 14, and the phase information of the alternating current may be expressed in other forms through the control module 14. The signals outputted by the output terminals of the third comparison unit CMP3 and the fourth comparison unit CMP4 may represent the impedance information of the alternating current, and the output terminals of the third comparison unit CMP3 and the fourth comparison unit CMP4 may also be connected to the control module 14, and the impedance information of the alternating current may be expressed in other forms through the control module 14.

[0067] Based on the above description of the AC phase and impedance detection circuit provided in this embodiment, it can be known that the phase information can be obtained based on the signal output by the first comparison module 14, and the AC impedance information can be obtained based on the signal output by the second comparison module 17. Therefore, the desired phase and impedance signals can be directly obtained based on the signals output by the two comparison modules. In addition, the first comparison module 14 and the second comparison module 17 can be connected to the control module 14, and the control module 14 outputs other forms of signals based on the signals output by the two comparison modules to characterize the desired phase and impedance signals. In this embodiment, the specific form of expression of the phase and impedance signals is not specifically limited.

[0068] In this embodiment, the first reference terminal X can provide a voltage corresponding to a preset threshold. The second reference terminal Y can provide a voltage corresponding to a preset voltage. When performing AC phase detection, the first comparison module 13 can compare the signal representing the voltage of the first clamp terminal M and the signal representing the voltage of the second clamp terminal N with the preset threshold, and obtain AC phase information through the signal output by the first comparison module 13. When performing AC impedance detection, the second comparison module 17 can compare the signal representing the voltage of the first clamp terminal M and the signal representing the voltage of the second clamp terminal N with the preset voltage, and obtain AC impedance information through the signal output by the second comparison module 17.

[0069] In order to more clearly understand the working mode of the AC phase and impedance detection circuit provided in this embodiment, the following is an example Figure 2The circuit structure shown is used as a basis to describe the AC phase and impedance detection process. At this time, the first input terminal of the first comparison unit CMP1 and the first input terminal of the second comparison unit CMP2 are both used as the non-phase input terminal of the comparator, the second input terminal of the first comparison unit CMP1 and the second input terminal of the second comparison unit CMP2 are both used as the inverting input terminal of the comparator, the first input terminal of the third comparison unit CMP3 and the first input terminal of the third comparison unit CMP3 are both used as the non-phase input terminal of the comparator, and the second input terminal of the third comparison unit CMP3 and the second input terminal of the fourth comparison unit CMP4 are both used as the inverting input terminal of the comparator.

[0070] When the voltage difference between the voltage at the first connection terminal A and the voltage at the second connection terminal B is greater than the preset voltage difference, the voltage at the first connection terminal A is larger, so that the third switch tube M3 is turned off, the fourth switch tube M4 is turned on, and the voltage at the first clamping terminal M is VDD+Vthp, where Vthp is the voltage drop of the fourth switch tube M4; the voltage at the second connection terminal B is smaller, so that the fifth switch tube M5 is turned on, the sixth switch tube M6 is turned off, and the voltage at the second clamping terminal N is VDD-Vthn, where Vthn is the voltage drop of the fifth switch tube M5; the first comparison unit CMP1 compares the voltage at the first clamping terminal M with the preset voltage, and outputs a signal (high level) indicating that the voltage at the first clamping terminal M is greater than the preset voltage, and the second comparison unit CMP2 compares the voltage at the second clamping terminal N with the preset voltage, and outputs a signal (low level) indicating that the voltage at the second clamping terminal N is less than the preset voltage, and the control module 14 obtains a signal that the voltage difference between the voltage at the first connection terminal A and the voltage at the second connection terminal B is greater than the preset voltage difference, and then determines the phase signal of the alternating current at this time.

[0071] When the voltage difference between the voltage at the second connection terminal B and the voltage at the first connection terminal A is greater than the preset voltage difference, the voltage at the second connection terminal B is relatively large, so that the third switch tube M3 is turned on, the fourth switch tube M4 is turned off, and the voltage at the first clamping terminal M is VDD-Vthn, where Vthn is the voltage drop of the third switch tube M3; the voltage at the second connection terminal B is relatively large, so that the fifth switch tube M5 is turned off, the sixth switch tube M6 is turned on, and the voltage at the second clamping terminal N is VDD+Vthp, where Vthp is the voltage drop of the sixth switch tube M6; the first comparison unit CMP1 compares the voltage at the first clamping terminal M with the preset voltage, and outputs a signal (low level) indicating that the voltage at the first clamping terminal M is less than the preset voltage, and the second comparison unit CMP2 compares the voltage at the second clamping terminal N with the preset voltage, and outputs a signal (high level) indicating that the voltage at the second clamping terminal N is greater than the preset voltage, and the control module 14 obtains a signal that the voltage difference between the voltage at the second connection terminal B and the voltage at the first connection terminal A is greater than the preset voltage difference, and then determines the phase signal of the alternating current at this time.

[0072] When the first comparison module 13 outputs a signal indicating that the voltage difference between the voltage at the second connection terminal B and the voltage at the first connection terminal A is less than a preset voltage difference, or a signal indicating that the voltage difference between the voltage at the first connection terminal A and the voltage at the second connection terminal B is less than a preset voltage difference, the control module 14 may send a control signal to the first switch tube M1 and the second switch tube M2 to control one of the first switch tube M1 and the second switch tube M2 to be turned on.

[0073] When the first switch tube M1 is turned off and the second switch tube M2 is turned on, the voltage at the first connection terminal A decreases and reaches the turn-on condition of the third switch tube M3. The first unidirectional switch tube N1 and the third switch tube M3 are turned on, and the fourth switch tube M4 and the second unidirectional switch tube N2 are turned off. The power supply voltage terminal VDD, the first unidirectional switch tube N1, the third switch tube M3, the first resistor R1, the AC impedance Rac, the second resistor R2, the second switch tube M2, the fourth resistor R4, and the reference ground terminal form a path. At this time, the voltage of the first clamping terminal M is VDD-Vthn, Vthn is the voltage drop of the third switch tube M3, and the second clamping module 12 is considered to be non-operating.

[0074] At this time, the voltage of the second clamping terminal N is (VDD-Vthn)*R4 / (R1+Rac+R2+R4), the third comparison unit CMP3 compares the voltage of the first clamping terminal M with the preset threshold, and the fourth comparison unit CMP4 compares the voltage of the second clamping terminal N with the preset threshold. Since the voltage of the second clamping terminal N is inversely proportional to the AC impedance Rac at this time, if the output of the fourth comparison unit CMP4 indicates that the voltage of the second clamping terminal N is greater than the preset threshold, the signal output by the fourth comparison unit CMP4 is reversed, indicating that the AC impedance Rac is smaller at this time.

[0075] Similarly, when the first switch tube M1 is turned on and the second switch tube M2 is turned off, the voltage at the second connection terminal B decreases and reaches the turn-on condition of the fifth switch tube M5, the third unidirectional switch tube N3 and the fifth switch tube M5 are turned on, the sixth switch tube M6 and the fourth unidirectional switch tube N4 are turned off, and the power supply voltage terminal VDD, the third unidirectional switch tube N3, the fifth switch tube M5, the second resistor R2, the AC impedance Rac, the first resistor R1, the first switch tube M1, the third resistor R3, and the reference ground terminal form a path. At this time, the voltage of the second clamping terminal N is VDD-Vthn, Vthn is the voltage drop of the fifth switch tube M5, and the first clamping module 11 is considered to be non-operating.

[0076] At this time, the voltage of the first clamping terminal M is (VDD-Vthn)*R3 / (R1+Rac+R2+R3), the third comparison unit CMP3 compares the voltage of the first clamping terminal M with the preset threshold, and the fourth comparison unit CMP4 compares the voltage of the second clamping terminal N with the preset threshold. Since the voltage of the first clamping terminal M is inversely proportional to the AC impedance Rac at this time, if the output of the third comparison unit CMP3 indicates that the voltage of the first clamping terminal M is greater than the preset threshold, the signal output by the third comparison unit CMP3 is reversed, indicating that the AC impedance Rac is smaller at this time.

[0077] The embodiment of the utility model can also provide an AC phase and impedance detection chip, which includes the AC phase and impedance detection circuit provided by any of the above embodiments.

[0078] Since the circuit structure and working mode of the AC power phase and impedance detection circuit in the AC power phase and impedance detection chip in this embodiment are the same as those of the AC power phase and impedance detection circuit in the previous embodiment, they will not be described in detail here.

[0079] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. An AC phase and impedance detection circuit, characterized in that: include: A first connection end and a second connection end for connecting to the neutral and live wires; A first clamping module, wherein a first clamping end of the first clamping module is connected to the first connecting end; A second clamping module, wherein a second clamping end of the second clamping module is connected to the second connecting end; A first comparison module compares the signal representing the first clamping terminal voltage and the signal representing the second clamping terminal voltage with a preset voltage, and outputs a signal representing the phase information of the alternating current; A first voltage dividing module connected to the first clamping end, and a second voltage dividing module connected to the second clamping end; A control module, connected to the output end of the first comparison module, the controlled end of the first voltage divider module, and the controlled end of the second voltage divider module respectively; controlled by the control module, the first voltage clamping module, the AC impedance of the AC power, and the second voltage divider module form a first impedance branch, or the second voltage clamping module, the AC impedance, and the first voltage divider module form a second impedance branch; The second comparison module compares the signal representing the first clamping terminal voltage and the signal representing the second clamping terminal voltage with a preset threshold value, and outputs a signal representing the AC impedance information.

2. The AC phase and impedance detection circuit according to claim 1, characterized in that: Also includes: A first resistor connected between the first connection end and the first clamping end; The second resistor is connected between the second connection end and the second clamping end.

3. The AC phase and impedance detection circuit according to claim 2, characterized in that: The first resistor and the second resistor have the same resistance value.

4. The AC phase and impedance detection circuit according to claim 1, characterized in that: The first voltage divider module includes a first switch tube and a third resistor connected in series, and the controlled end of the first switch tube serves as the controlled end of the first voltage divider module; the second voltage divider module includes a second switch tube and a fourth resistor connected in series, and the controlled end of the second switch tube serves as the controlled end of the second voltage divider module.

5. The AC phase and impedance detection circuit according to claim 4, characterized in that: The third resistor and the fourth resistor have the same resistance value.

6. The AC phase and impedance detection circuit according to claim 1, characterized in that: The clamping range of the first clamping module and the second clamping module is from a first voltage to a second voltage, and the first voltage is greater than the second voltage.

7. The AC phase and impedance detection circuit according to claim 6, characterized in that: The first clamping module includes a third switch tube and a fourth switch tube, wherein the first end of the third switch tube and the first end of the fourth switch tube are connected to the power supply voltage end, the second end of the third switch tube is connected to the power supply voltage end, the third end of the third switch tube and the second end of the fourth switch tube are connected to the first clamping end, and the third end of the fourth switch tube is connected to the reference ground end.

8. The AC phase and impedance detection circuit according to claim 7, characterized in that: The first clamping module further includes: A first unidirectional switch tube is connected between the power supply voltage terminal and the second end of the third switch tube, and the conduction direction of the first unidirectional switch tube is from the power supply voltage terminal to the second end of the third switch tube; The second unidirectional switch tube is connected between the third end of the fourth switch tube and the reference ground end; the conduction direction of the second unidirectional switch tube is from the third end of the fourth switch tube to the reference ground end.

9. The AC phase and impedance detection circuit according to claim 7, characterized in that: The third switch tube is an NMOS transistor, and the fourth switch tube is a PMOS transistor.

10. The AC phase and impedance detection circuit according to claim 1, characterized in that: The first comparison module includes a first comparison unit and a second comparison unit; the first input end of the first comparison unit is connected to the first clamping end, the first input end of the second comparison unit is connected to the second clamping end, and the second input end of the first comparison unit and the second input end of the second comparison unit are connected to the first reference end; And / or, the second comparison module includes a third comparison unit and a fourth comparison unit; the first input end of the third comparison unit is connected to the first clamping end, the first input end of the fourth comparison unit is connected to the second clamping end, and the second input end of the third comparison unit and the second input end of the fourth comparison unit are connected to the second reference end.

Images