Voltage detection circuit

Abstract

The utility model relates to the technical field of power supply, in particular to a voltage detection circuit, which comprises a full-bridge rectification circuit used for rectifying an input alternating-current voltage signal into a pulsating direct-current voltage signal; the first filter circuit is used for carrying out filtering processing and voltage division processing on the pulsating direct-current voltage signal or an input direct-current voltage signal so as to output a direct-current voltage signal after voltage division processing; the second filter circuit is used for buffering the direct-current voltage signal output by the first filter circuit so as to reduce the ripple peak value; the amplitude limiting clamping circuit is connected with the output end of the first filter circuit and is used for carrying out voltage clamping and / or delay on the direct-current voltage signal input into the second filter circuit; and the hysteresis comparison circuit is connected with the output end of the second filter circuit and the output end of the amplitude limiting clamping circuit, and is used for comparing the voltage signals and outputting digital signals. According to the scheme, the alternating current and the direct current can be detected at the same voltage point only by using hardware.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply, and particularly relates to a voltage detection circuit. Background Art

[0002] With the development of DC power supply technology, there is a need to meet certain DC detection requirements in electrical equipment; at the same time, there is also a need to meet AC detection requirements. However, in the related technical solutions, when there is a need for AC and DC constant voltage detection at the same time, generally an MCU (Microcontroller Unit) is required, and the software control method is used to achieve the requirement that the detection time remains consistent at the same voltage point for AC and DC. However, at present, it is still impossible to achieve the consistency of the detection time at the same voltage point for AC and DC only by using a set of hardware devices.

[0003] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0004] The utility model provides a voltage detection circuit, which can effectively overcome the defects existing in the prior art.

[0005] Other characteristics and advantages of the utility model will become apparent through the following detailed description, or will be partially learned through the practice of the present disclosure.

[0006] According to the first aspect of the utility model, a voltage detection circuit is provided, including: a full-bridge rectifier circuit, a first filter circuit, a second filter circuit, a limiting and clamping circuit, and a hysteresis comparison circuit; wherein,

[0007] The full-bridge rectifier circuit is used to rectify the input AC voltage signal into a pulsating DC voltage signal;

[0008] The first filter circuit is connected to the output end of the full-bridge rectifier circuit, and is used to filter and divide the voltage of the pulsating DC voltage signal or the input DC voltage signal, so as to output the DC voltage signal after voltage division processing;

[0009] The second filter circuit is connected to the output end of the first filter circuit, and is used to buffer the DC voltage signal output by the first filter circuit, so as to reduce the peak-to-peak value of the ripple;

[0010] The limiting and clamping circuit is connected to the output end of the first filter circuit, and is used to clamp the voltage and / or delay the DC voltage signal input to the second filter circuit;

[0011] A hysteresis comparison circuit, connected to the output terminals of the second filter circuit and the limiter clamping circuit, for comparing voltage signals and outputting digital signals.

[0012] In some exemplary embodiments, the first filter circuit is an RC filter circuit; the second filter circuit is a follower filter circuit.

[0013] In some exemplary embodiments, the RC filter circuit includes: a first diode D1, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, and a second capacitor C2;

[0014] The first end of the first diode D1 is connected to the output terminal of the full-bridge rectifier circuit, and the second end of the first diode D1 is connected to the first end of the first resistor R1; the second end of the first resistor R1 is respectively connected to the first end of the first capacitor C1 and the first end of the second resistor R2; the second end of the first capacitor C1 is connected to the ground terminal; the second end of the second resistor R2, the first end of the third resistor R3, and the first end of the second capacitor C2 are connected to the input terminal of the second filter circuit and the input terminal of the limiter clamping circuit; the second end of the third resistor R3 and the second end of the second capacitor C2 are respectively connected to the ground terminal.

[0015] In some exemplary embodiments, the follower filter circuit includes: a first amplifier U1, a second amplifier U2, a magnetic bead L1, a third capacitor C3, and a fourth capacitor C4;

[0016] The first end of the magnetic bead L1 is connected to the power supply terminal, the second end of the magnetic bead L1 is connected to the second end of the third capacitor C3 and the power supply terminal of the first amplifier U1, and the first end of the third capacitor C3 is connected to the ground terminal; the non-inverting input terminal of the first amplifier U1 is connected to the output terminal of the RC filter circuit and the input terminal of the hysteresis comparison circuit; the output terminal of the first amplifier U1 is connected to the inverting input terminal of the first amplifier U1 and the first end of a fourth resistor R4; the ground terminal of the first amplifier U1 is connected to the ground terminal; the second end of the fourth resistor R4 is connected to the first end of the fourth capacitor C4 and the non-inverting input terminal of the second amplifier U2; the second end of the fourth capacitor C4 is connected to the ground terminal; the inverting input terminal of the second amplifier U2 is connected to the output terminal.

[0017] In some exemplary embodiments, the limiter clamping circuit includes a first limiter clamping circuit and a second limiter clamping circuit connected in series.

[0018] In some exemplary embodiments, the limiter clamping circuit includes: a second diode D2, a third diode D3, a fourth diode D4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a fifth capacitor C5;

[0019] The first end of the second diode D2 is connected to the first end of the third diode D3; the second end of the second diode D2 and the first end of the fifth resistor are connected to the power supply terminal; the second end of the fifth resistor R5 is connected to the second end of the third diode D3 and the first end of the sixth resistor R6; the second end of the sixth resistor R6 is connected to the first end of the fourth diode D4, the first end of the fifth capacitor C5, and the first end of the seventh resistor R7, and is also connected to the power supply terminal; the second end of the fourth diode D4 and the second end of the fifth capacitor C5 are connected to the ground terminal; the second end of the seventh resistor R7 is connected to the input terminal of the hysteresis comparator circuit.

[0020] In some exemplary embodiments, 7. the hysteresis comparator circuit includes: an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a third amplifier U3, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, and a fifth diode D5;

[0021] The second end of the eighth resistor R8, the first end of the ninth resistor R9, and the first end of the sixth capacitor C6 are connected to the non-inverting input terminal of the third amplifier U3; the first end of the eighth resistor R8 is connected to the output terminal of the second filter circuit; the inverting input terminal of the third amplifier U3 is connected to the output terminal of the limiting and clamping circuit; the output terminal of the third amplifier U3 is connected to the second end of the sixth capacitor C6, the second end of the ninth resistor R9, the first end of the seventh capacitor C7, the first end of the eighth capacitor C8, and the first end of the fifth diode D5; the second end of the seventh capacitor C7 and the second end of the eighth capacitor C8 are connected to the ground terminal; the second end of the fifth diode D5 is connected to the first end of the tenth resistor R10; the second end of the tenth resistor R10 is connected to the power supply terminal.

[0022] The voltage detection circuit provided by the embodiments of the present invention can input alternating current or direct current. By setting a full-bridge rectifier circuit, the input alternating voltage signal can be rectified into a pulsating direct voltage signal. The first filter circuit can filter and divide the pulsating direct voltage signal or the input direct voltage signal to filter it into a direct voltage with small fluctuations. Then, the limiting and clamping circuit is used to protect the second filter circuit on the one hand and limit the peak value of the voltage signal after rectification and filtering on the other hand to narrow the gap between the AC and DC voltage points, so that AC and DC can be detected at the same voltage point. By setting a hysteresis comparator circuit, the hysteresis range is compatible with a wider range of AC and DC voltages, thereby realizing that AC and DC are detected at the same voltage point.

[0023] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 A schematic diagram showing the module composition of a voltage detection circuit in an exemplary embodiment of the present utility model;

[0026] Figure 2 A schematic circuit diagram showing a voltage detection circuit in an exemplary embodiment of the present utility model;

[0027] Figure 3 A schematic diagram showing a full-bridge rectifier circuit in an exemplary embodiment of the present utility model;

[0028] Figure 4 A schematic diagram showing an RC filter circuit in an exemplary embodiment of the present utility model;

[0029] Figure 5 A schematic diagram showing a follower filter circuit in an exemplary embodiment of the present utility model;

[0030] Figure 6 A schematic diagram showing a limiting and clamping circuit in an exemplary embodiment of the present utility model;

[0031] Figure 7 A schematic diagram showing a hysteresis comparison circuit in an exemplary embodiment of the present utility model. Detailed implementation manners

[0032] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more complete and comprehensive, and will fully convey the concept of the example embodiments to those skilled in the art. The features, structures, or characteristics described can be combined in any suitable manner in one or more embodiments.

[0033] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repeated description will be omitted.

[0034] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be completely conveyed to those skilled in the art. It should be understood that in the disclosure of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention. Unless otherwise clearly defined and limited, the terms "installation", "connection", "coupling", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. It can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly defined. Those of ordinary skill in the art should be able to understand the specific meaning of the above terms in the present invention according to the specific situation.

[0035] In view of the disadvantages and deficiencies of the prior art, a voltage detection circuit is provided in this exemplary embodiment. Refer to Figure 1 As shown, the voltage detection circuit includes: a full-bridge rectifier circuit 11, a first filter circuit 12, a second filter circuit 13, a clamping circuit 14, and a hysteresis comparison circuit 15. Among them, the full-bridge rectifier circuit 11 can be used to rectify the input AC voltage signal into a pulsating DC voltage signal; the first filter circuit 12 is connected to the output end of the full-bridge rectifier circuit and can be used to filter and divide the pulsating DC voltage signal or the input DC voltage signal to output the DC voltage signal after voltage division processing; the second filter circuit 13 is connected to the output end of the first filter circuit and can be used to buffer the DC voltage signal output by the first filter circuit to reduce the peak-to-peak value of the ripple; the clamping circuit 14 is connected to the output end of the first filter circuit and can be used to clamp and / or delay the DC voltage signal input to the second filter circuit; the hysteresis comparison circuit 15 is connected to the output end of the second filter circuit 13 and the output end of the clamping circuit 14 and can be used to compare the voltage signal and output a digital signal.

[0036] Exemplarily, refer to Figure 2As shown, an anti-interference circuit can also be connected upstream of the full-bridge rectifier circuit, including: terminal P1, capacitor C9, and varistor RV1. Among them, the first end and the fourth end of terminal P1 are connected and connected to the second end of capacitor C11 and the second end of capacitor C10 of the full-bridge rectifier circuit, and then connected to the ground terminal (EARTH terminal). After the second end and the fifth end of terminal P1 are connected, they are connected to the second end of varistor RV1, the second end of the ninth capacitor C9, and the first end of transformer L2; the third end and the sixth end of terminal P1 are connected to the first end of varistor RV1 and the first end of the ninth capacitor C9 and connected to transformer L2; the varistor RV1 and the ninth capacitor C9 are in a parallel structure.

[0037] Exemplarily, the full-bridge rectifier circuit can be used to convert an AC signal into a DC signal. For example, the full-bridge rectifier circuit can include four power switch elements, a transformer, and output filter capacitors. Among them, the power switch elements are usually diodes or power MOSFETs and form a full-wave rectifier bridge. For example, it can be two pairs of symmetric power diodes or power MOSFETs, each pair connected in a half-bridge configuration. In the full-bridge rectifier circuit, when the positive half-cycle of the input AC signal is present, one pair of diodes or MOSFETs conducts, directing the current to the output terminal; when the negative half-cycle of the input AC signal is present, the other pair of diodes or MOSFETs conducts, also directing the current to the output terminal. By means of alternating conduction, the full-bridge rectifier circuit can achieve complete rectification of the input AC signal.

[0038] For example, referring to Figure 3As shown in the figure, the full-bridge rectifier circuit may include: a plurality of diodes (diode D7, diode D8), a plurality of capacitors (capacitor C10, capacitor C11, capacitor C12, capacitor C13, capacitor C14, capacitor C15, capacitor C16; capacitor C15, capacitor C16 may be polarized capacitors), a rectifier bridge D6, a transformer L2, and a plurality of resistors (resistor R51, resistor R52). Among them, the third terminal of the transformer L2 is respectively connected to the first terminal of the seventh diode D7, the first terminal of the capacitor C11, the first terminal of the capacitor C12, and the second terminal of the rectifier bridge D6; the second terminal of the transformer L2 is respectively connected to the first terminal of the eighth diode D8, the first terminal of the capacitor C10, the second terminal of the capacitor C12, and the fourth terminal of the rectifier bridge D6; the second terminals of the capacitor C10 and the capacitor C11 are connected to the ground terminal (EARTH). The second terminals of the seventh diode D7 and the eighth diode D8 are connected as the output terminal of the full-bridge rectifier circuit. After the capacitor C12 is connected in series with the capacitor C10, it forms a parallel structure with the capacitor C11. The first terminal of the rectifier bridge D6 is respectively connected to the first terminal of the capacitor C14, the positive electrode of the capacitor C15, and the first terminal of the resistor R51, and is connected to the power supply terminal VEE. The third terminal of the rectifier bridge D6 is respectively connected to the first terminal of the capacitor C13, the negative electrode of the capacitor C16, and the second terminal of the resistor R52, and is connected to the GND terminal. The negative electrode of the capacitor C15 is connected to the positive electrode of the capacitor C16, the second terminal of the resistor R51, and the first terminal of the resistor R52. The second terminals of the capacitor C13 and the capacitor C14 are connected and connected to the ground terminal (EARTH). The capacitor C15 and the capacitor C16 are connected in series to form a series structure; the resistor R51 and the resistor R52 are in a series structure.

[0039] By setting the full-bridge rectifier circuit, when powered by current, the full-bridge rectifier circuit can full-wave rectify alternating current into pulsating direct current, and there is no other change for the input direct current. The average value of the pulsating direct current is 0.9Urms, which is 0.1Urms different from the magnitude of the direct current power supply. The average value of the pulsating direct current of half-wave rectification is 0.45Urms, which is 0.55Urms different from the magnitude of the direct current power supply. At the same time, the ripple of full-wave rectification is also smaller than that of half-wave rectification, so that the full-wave only needs a smaller filter capacitor to be close to direct current. At the same time, using a smaller filter capacitor can make the operation time easier to meet within 35ms; using full-wave rectification can eliminate the need to consider the problem of positive and negative DC wiring.

[0040] Exemplarily, the first filter circuit is an RC filter circuit. Specifically, refer to Figure 4As shown in the figure, the RC filter circuit includes: a first diode D1, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, and a second capacitor C2. Among them, the first end of the first diode D1 is connected to the second end of the seventh diode D7 and the second end of the eighth diode D8 of the full-bridge rectifier circuit. The second end of the first diode D1 is connected to the first end of the first resistor R1; the second end of the first resistor R1 is respectively connected to the first end of the first capacitor C1 and the first end of the second resistor R2; the second end of the first capacitor C1 is connected to the GND terminal; the second end of the second resistor R2, the first end of the third resistor R3, and the first end of the second capacitor C2 are connected and used as the output terminal of the RC filter circuit, which is connected to the input terminal of the second filter circuit and the input terminal of the clamping circuit; the second end of the third resistor R3 and the second end of the second capacitor C2 are respectively connected to the GND terminal. Among them, the GND terminal to which the first capacitor C1 is connected and the GND terminal to which the second capacitor C2 is connected can be different GND terminals.

[0041] Specifically, by setting the RC filter circuit, RC filtering is performed on the signal after full-bridge rectification and voltage division is performed on the voltage signal. The voltage division needs to be compatible with both DC power supply and AC power supply. First, the minimum DC power supply (for example, 160V) can be used to adjust the resistor voltage division and then enter the follower, and finally enter the non-inverting terminal of the hysteresis comparator. It is necessary to make the input voltage greater than the upper limit value of the hysteresis comparator to make the hysteresis comparator output a high level. After adjusting the resistor voltage division through DC, when using AC power supply, only the value of the filter capacitor needs to be adjusted so that the DC voltage after filtering and voltage division of the minimum AC power supply (for example, 160Vac) is close to that after voltage division of the minimum DC power supply, then the hysteresis comparator can be triggered to output a high level. The charging time constant of the RC filter is less than the discharging time constant. In this solution, the charging time constant can be 1 / 8 of the discharging time constant, which is convenient for making the DC voltage after RC filtering close to that during DC power supply.

[0042] Exemplarily, the second filter circuit is a follower filter circuit. Refer to Figure 5 As shown in the figure, among them, the follower filter circuit includes: a first amplifier U1, a second amplifier U2, a magnetic bead L1, a third capacitor C3, and a fourth capacitor C4.

[0043] The non-inverting input terminal of the first amplifier U1 can serve as the input terminal of the follower filter circuit, and is connected to the output terminal of the RC filter circuit and the input terminal of the hysteresis comparator circuit; the output terminal of the first amplifier U1 is connected to the inverting input terminal of the first amplifier U1 and the first terminal of the fourth resistor R4; the ground terminal of the first amplifier U1 is connected to the ground terminal; the second terminal of the fourth resistor R4 is connected to the first terminal of the fourth capacitor C4 and the non-inverting input terminal of the second amplifier U2; the second terminal of the fourth capacitor C4 is connected to the ground terminal; the inverting input terminal of the second amplifier U2 is connected to the output terminal and serves as the output terminal of the follower filter circuit. In addition, the first terminal of the bead L1 is connected to the power supply terminal VDD, the second terminal of the bead L1 is connected to the second terminal of the third capacitor C3 and the power supply terminal of the first amplifier U1, and the first terminal of the third capacitor C3 is connected to the ground terminal GND.

[0044] Among them, the follower filter circuit can achieve high input impedance and low output impedance, and has little influence on the current of the front and rear stages during voltage signal transmission; the filter is mainly used to further reduce the peak-to-peak value of the ripple during AC power supply filtering, so as to meet the requirement that the minimum value of the ripple will not be lower than the lower limit value of the hysteresis comparator when powered by 160Vac.

[0045] Exemplarily, the limiting and clamping circuit includes a series-connected first limiting and clamping circuit and a second limiting and clamping circuit. Refer to Figure 6 As shown, the limiting and clamping circuit includes: the second diode D2, the third diode D3, the fourth diode D4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the fifth capacitor C5. Among them, the first terminal of the second diode D2 is connected to the first terminal of the third diode D3, serves as the input terminal of the limiting and clamping circuit, and is connected to the non-inverting input terminal of the first amplifier U1 in the follower filter circuit and the first terminal of the second capacitor C2. The second terminal of the second diode D2 and the first terminal of the fifth resistor are connected to the power supply terminal VDD; the second terminal of the fifth resistor R5 is connected to the second terminal of the third diode D3 and the first terminal of the sixth resistor R6; the second terminal of the sixth resistor R6 is connected to the first terminal of the fourth diode D4, the first terminal of the fifth capacitor C5, and the first terminal of the seventh resistor R7, and is connected to the power supply terminal; the second terminal of the fourth diode D4 and the second terminal of the fifth capacitor C5 are connected to the ground terminal; the second terminal of the seventh resistor R7 serves as the output terminal of the limiting and clamping circuit and is connected to the input terminal of the hysteresis comparator circuit.

[0046] Specifically, for the two-stage clamping circuit, the first stage connects the K pole of diode D2 to the power supply terminal VDD and the A pole to the input terminal of the follower. At the same time, the power supply terminal VDD is also the voltage for powering the follower, clamping the voltage input to the follower to be one forward voltage drop of a diode larger than VDD, protecting the follower from being damaged due to high input voltage. This clamping diode can be a Schottky diode with a low forward voltage drop.

[0047] In addition, the second-stage clamping can be composed of the reference voltage VCC for the hysteresis comparator and diode D4. The reference voltage generation circuit can generate the reference voltage VCC by connecting two resistors (the fifth resistor R5 and the sixth resistor R6) in series with a high-precision reference voltage chip to the power supply terminal VDD. The selection of the current-limiting resistor can be configured according to the minimum regulated current of the reference voltage chip and the generation of the clamping reference voltage. In this solution, the reference voltage for the second-stage clamping can be obtained from the second series resistor of the reference voltage Vcc circuit provided to the hysteresis comparator, clamping the input voltage to this reference voltage plus the forward voltage drop of the diode. This stage of clamping is mainly to clamp the maximum value of the ripple voltage when powered by alternating current, making the delay generated on the RC filter after entering the follower close to the delay when powered by direct current. If the above second-stage clamping is missing, the presence of the peak value of the voltage ripple during AC power supply will cause the upper limit value of the hysteresis comparator to be reached faster under the same RC time constant, resulting in a relatively large difference in delay time.

[0048] Exemplarily, referring to Figure 7 As shown, the hysteresis comparison circuit includes: the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, the third amplifier U3, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8, and the fifth diode D5. Specifically, the second end of the eighth resistor R8, the first end of the ninth resistor R9, and the first end of the sixth capacitor C6 are connected to the non-inverting input terminal of the third amplifier U3; the first end of the eighth resistor R8 is connected to the output terminal of the second amplifier U2 of the second filtering circuit. The inverting input terminal of the third amplifier U3 is connected to the second end of the seventh resistor R7 of the limiting and clamping circuit; the output terminal of the third amplifier U3 is connected to the second end of the sixth capacitor C6, the second end of the ninth resistor R9, the first end of the seventh capacitor C7, the first end of the eighth capacitor C8, and the first end of the fifth diode D5; the second ends of the seventh capacitor C7 and the eighth capacitor C8 are connected to the ground terminal GND; the seventh capacitor C7 and the eighth capacitor C8 are in a parallel structure. The second end of the fifth diode D5 is connected to the first end of the tenth resistor R10; the second end of the tenth resistor R10 is connected to the power supply terminal VCC.

[0049] For the voltage detection circuit of the present utility model, when there is AC or DC input, after full-bridge rectification, the AC is rectified into pulsating DC, and the pulsating DC is filtered into DC with small fluctuations through an RC filtering circuit. Before entering the follower filtering circuit, the limiting and clamping circuit protects the follower filtering circuit on the one hand, and limits the peak value of the signal after rectification and filtering on the other hand, so as to narrow the gap between the AC and DC voltage points, enabling the AC and DC to be detected at the same voltage point. For example, an AC effective value of 220 VAC and a DC of 220 V can be detected simultaneously, causing the hysteresis comparison circuit to finally output a high level. The hysteresis range of the hysteresis comparison circuit is compatible with a wider range of AC and DC voltages, which helps to achieve the detection of AC and DC at the same voltage point. This solution can achieve the detection of AC and DC at the same voltage point on the same set of hardware without software implementation, reducing the investment in software development and the software maintenance cost.

[0050] After considering the specification and the practice of the invention disclosed herein, those skilled in the art will readily conceive of other embodiments of the present disclosure. This application is intended to cover any variations, uses, or adaptations of the present disclosure, which follow the general principles of the present disclosure and include well-known knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of the present disclosure are pointed out by the claims.

[0051] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

Claims

1. A voltage detection circuit, characterized in that, Comprising: Full-bridge rectifier circuit, first filter circuit, second filter circuit, limiting and clamping circuit, hysteresis comparison circuit; wherein, The full-bridge rectifier circuit is used to rectify the input AC voltage signal into a pulsating DC voltage signal; The first filter circuit is connected to the output end of the full-bridge rectifier circuit and is used to filter and divide the pulsating DC voltage signal or the input DC voltage signal to output the DC voltage signal after voltage division processing; The second filter circuit is connected to the output end of the first filter circuit and is used to buffer the DC voltage signal output by the first filter circuit to reduce the peak-to-peak ripple; The limiting and clamping circuit is connected to the output end of the first filter circuit and is used to clamp the voltage and / or delay the DC voltage signal input to the second filter circuit; The hysteresis comparison circuit is connected to the output end of the second filter circuit and the output end of the limiting and clamping circuit and is used to compare the voltage signal and output a digital signal.

2. The voltage detection circuit according to claim 1, wherein The first filter circuit is an RC filter circuit; the second filter circuit is a follower filter circuit.

3. The voltage detection circuit according to claim 2, wherein The RC filter circuit includes: first diode D1, first resistor R1, second resistor R2, third resistor R3, first capacitor C1 and second capacitor C2; The first end of the first diode D1 is connected to the output end of the full-bridge rectifier circuit, and the second end of the first diode D1 is connected to the first end of the first resistor R1; the second end of the first resistor R1 is respectively connected to the first end of the first capacitor C1 and the first end of the second resistor R2; the second end of the first capacitor C1 is connected to the ground terminal; the second end of the second resistor R2, the first end of the third resistor R3, and the first end of the second capacitor C2 are connected to the input end of the second filter circuit and the input end of the limiting and clamping circuit; the second end of the third resistor R3 and the second end of the second capacitor C2 are respectively connected to the ground terminal.

4. The voltage detection circuit according to claim 2, characterized in that The follower filter circuit includes: first amplifier U1, second amplifier U2, magnetic bead L1, third capacitor C3, fourth capacitor C4; The first end of the magnetic bead L1 is connected to the power supply terminal, the second end of the magnetic bead L1 is connected to the second end of the third capacitor C3 and the power supply terminal of the first amplifier U1, and the first end of the third capacitor C3 is connected to the ground terminal; the non-inverting input terminal of the first amplifier U1 is connected to the output end of the RC filter circuit and the input end of the hysteresis comparison circuit; the output end of the first amplifier U1 is connected to the inverting input terminal of the first amplifier U1 and the first end of the fourth resistor R4; the ground terminal of the first amplifier U1 is connected to the ground terminal; the second end of the fourth resistor R4 is connected to the first end of the fourth capacitor C4 and the non-inverting input terminal of the second amplifier U2; the second end of the fourth capacitor C4 is connected to the ground terminal; the inverting input terminal of the second amplifier U2 is connected to the output terminal.

5. The voltage detection circuit according to claim 1, wherein The limiting and clamping circuit includes a series-connected first limiting and clamping circuit and a second limiting and clamping circuit.

6. The voltage detection circuit according to claim 1 or 5, characterized in that, The limiting and clamping circuit includes: second diode D2, third diode D3, fourth diode D4, fifth resistor R5, sixth resistor R6, seventh resistor R7, fifth capacitor C5; The first end of the second diode D2 is connected to the first end of the third diode D3; the second end of the second diode D2 and the first end of the fifth resistor are connected to the power supply terminal; the second end of the fifth resistor R5 is connected to the second end of the third diode D3 and the first end of the sixth resistor R6; the second end of the sixth resistor R6 is connected to the first end of the fourth diode D4, the first end of the fifth capacitor C5, and the first end of the seventh resistor R7, and is also connected to the power supply terminal; the second end of the fourth diode D4 and the second end of the fifth capacitor C5 are connected to the ground terminal; the second end of the seventh resistor R7 is connected to the input terminal of the hysteresis comparison circuit.

7. The voltage detection circuit according to claim 1, wherein The hysteresis comparison circuit includes: an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a third amplifier U3, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, and a fifth diode D5. The second end of the eighth resistor R8, the first end of the ninth resistor R9, and the first end of the sixth capacitor C6 are connected to the non-inverting input terminal of the third amplifier U3; the first end of the eighth resistor R8 is connected to the output terminal of the second filter circuit; the inverting input terminal of the third amplifier U3 is connected to the output terminal of the limiting and clamping circuit; the output terminal of the third amplifier U3 is connected to the second end of the sixth capacitor C6, the second end of the ninth resistor R9, the first end of the seventh capacitor C7, the first end of the eighth capacitor C8, and the first end of the fifth diode D5; the second end of the seventh capacitor C7 and the second end of the eighth capacitor C8 are connected to the ground terminal; the second end of the fifth diode D5 is connected to the first end of the tenth resistor R10; the second end of the tenth resistor R10 is connected to the power supply terminal.

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