Self-powered overvoltage and undervoltage detection circuit
By designing a self-powered over-voltage and under-voltage detection circuit and utilizing a photocoupler and a voltage divider circuit, the problem of the existing circuit requiring independent power supply is solved, and the miniaturization of the circuit and high-precision detection are achieved.
Patent Information
- Application Number
- CN202422755584.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-09-09
- Estimated Expiration
- 2034-11-12
AI Technical Summary
Existing isolated overvoltage and undervoltage detection circuits require auxiliary power supply, which makes the circuit complex and bulky, making it difficult to meet the market demand for small and streamlined circuits.
A self-powered over- and under-voltage detection circuit design is adopted, and a voltage divider circuit composed of a photocoupler, a transistor, and a MOS tube is used to realize over- and under-voltage detection through the self-powered power supply of the detected circuit.
The circuit has good consistency, small size, high detection accuracy, and does not require independent power supply, and is suitable for multi-channel isolated output power supply.
Smart Images
Figure CN223320484U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of power electronics, and in particular relates to a self-powered over-voltage and under-voltage detection circuit. Background Art
[0002] An overvoltage or undervoltage protection circuit is a protective circuit installed in an electrical system to protect electrical equipment or circuits from damage or destruction caused by overvoltage or undervoltage conditions. Most existing isolated overvoltage or undervoltage detection circuits consist of a reference comparator and optocoupler, requiring auxiliary power supply at the detection end, resulting in a complex and bulky circuit. For example, overvoltage or undervoltage detection relies on a dual comparator, which requires an independent power supply from the detection voltage. Reducing the size and streamlining existing circuits while meeting detection technology requirements has become a new market requirement for this circuit and a new challenge facing technicians in this field. Utility Model Content
[0003] In response to the above technical problems, the utility model provides a self-powered over-voltage and under-voltage detection circuit, which uses the detected circuit for self-power supply, solving the technical problem that the existing circuit requires independent power supply. The circuit has good consistency and small size.
[0004] The utility model solves the above problems through the following technical means:
[0005] A self-powered over- and under-voltage detection circuit, characterized in that it includes a photocoupler, an under-voltage detection circuit, and an over-voltage detection circuit, wherein: the primary port of the photocoupler is connected to the positive electrode of the power input through a seventeenth resistor, the primary port of the photocoupler is connected to the C pole of a thirteenth transistor, the secondary port of the photocoupler is connected to a -5V power supply, and the secondary port of the photocoupler is divided into two paths: one path is connected to the +5V power supply through an eighteenth resistor, and the other path is connected to the signal port through a tenth diode and a nineteenth resistor connected in parallel; the under-voltage detection circuit includes a twelfth transistor, a thirteenth transistor, and an under-voltage divider circuit, the E pole of the twelfth transistor is connected to the positive electrode of the power input, and the C pole of the twelfth transistor is connected to the positive electrode of the power input. The B pole of the thirteenth transistor is connected through the thirty-second resistor and the thirty-third resistor, the positive pole of the power input is connected to the B pole of the twelfth transistor after being divided by the undervoltage divider circuit, and the E pole of the thirteenth transistor is connected to the negative pole of the power input; the overvoltage detection circuit includes a fifteenth transistor, a fourteenth MOS transistor, and an overvoltage divider circuit, the E pole of the fifteenth transistor is connected to the positive pole of the power input, the C pole of the fifteenth transistor is connected to the G pole of the fourteenth MOS transistor through the thirty-ninth resistor, the positive pole of the power input is connected to the B pole of the fifteenth transistor after being divided by the overvoltage divider circuit, the D pole of the fourteenth MOS transistor is connected between the thirty-second resistor and the thirty-third resistor, and the S pole of the fourteenth MOS transistor is connected to the negative pole of the power input.
[0006] Preferably, an eighth capacitor is connected between the signal port of the photoelectric coupler and the -5V power supply.
[0007] Preferably, a thirty-fifth resistor is connected between the E pole and the B pole of the thirteenth transistor.
[0008] Preferably, the undervoltage divider circuit includes a thirty-fourth resistor, a thirty-sixth resistor, a thirty-seventh resistor, a thirty-eighth resistor and a forty-fifth resistor, wherein: the thirty-sixth resistor and the thirty-seventh resistor are connected in parallel and then connected in series with the thirty-eighth resistor between the positive pole of the power input and the negative pole of the power input; the thirty-fourth resistor and the forty-fifth resistor are connected in series and then connected in parallel at both ends of the thirty-seventh resistor, and the voltage between the thirty-fourth resistor and the forty-fifth resistor is led to the B pole of the twelfth transistor.
[0009] Preferably, the overvoltage divider circuit includes a 40th resistor, a 42nd resistor, a 43rd resistor, a 44th resistor and a 46th resistor, wherein: the 42nd resistor and the 43rd resistor are connected in parallel and then connected in series with the 44th resistor between the positive pole of the power input and the negative pole of the power input; the 40th resistor and the 46th resistor are connected in series and then connected in parallel at both ends of the 43rd resistor, and the voltage between the 40th resistor and the 46th resistor is led to the B pole of the 15th transistor.
[0010] The self-powered over-voltage and under-voltage detection circuit of the utility model has the following beneficial effects:
[0011] The detection circuit includes a photoelectric coupler, an undervoltage detection circuit, and an overvoltage detection circuit. The primary port of the photoelectric coupler is connected to the positive pole of the power input, the primary port of the photoelectric coupler is connected to the C pole of the thirteenth transistor, the secondary port of the photoelectric coupler is connected to the -5V power supply, and the secondary port of the photoelectric coupler is divided into two paths. The undervoltage detection circuit includes the twelfth transistor, the thirteenth transistor, and the undervoltage divider circuit. The overvoltage detection circuit includes the fifteenth transistor, the fourteenth MOS transistor, and the overvoltage divider circuit. The circuit uses the detected circuit for self-power supply, solving the technical problem that the existing circuit requires independent power supply. When the detected voltage is out of the range, the TTL is reported as a high level. When the detected voltage is within the range, the TTL is reported as a low level. The circuit has obvious advantages in multi-channel isolated output power supply, good consistency, small size, and high detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the implementation. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0013] Figure 1 It is an overall circuit diagram of the utility model. DETAILED DESCRIPTION
[0014] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and 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, and therefore cannot be understood as a limitation on the present invention. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.
[0015] The present invention will be described in detail below with reference to the accompanying drawings.
[0016] like Figure 1 As shown, the self-powered over- and undervoltage detection circuit includes a photocoupler U4, an undervoltage detection circuit, an overvoltage detection circuit, and an isolation reporting circuit. In the figure, the core of the isolation reporting circuit is the photocoupler U4. Specifically, the primary port 1 of the photocoupler U4 is connected to the positive power input VIN+ through the seventeenth resistor R17, the primary port 2 of the photocoupler U4 is connected to the C pole of the thirteenth transistor Q13, the secondary port 3 of the photocoupler U4 is connected to the -5V power supply, and the secondary port 4 of the photocoupler U4 is divided into two paths: one path is connected to the +5V power supply through the eighteenth resistor R18, and the other path is connected to the signal port TTL through the parallel tenth diode D10 and the nineteenth resistor R19. An eighth capacitor C8 is connected between the signal port TTL of the photocoupler U4 and the -5V power supply.
[0017] In the figure, the undervoltage detection circuit includes a twelfth transistor Q12, a thirteenth transistor Q13, and an undervoltage divider circuit. The E terminal of the twelfth transistor Q12 is connected to the positive power input terminal VIN+, and the C terminal of the twelfth transistor Q12 is connected to the B terminal of the thirteenth transistor Q13 via a thirty-second resistor R32 and a thirty-third resistor R33. The positive power input terminal VIN+ is connected to the B terminal of the twelfth transistor Q12 after being divided by the undervoltage divider circuit. The E terminal of the thirteenth transistor Q13 is connected to the negative power input terminal VIN-. A thirty-fifth resistor R35 is connected between the E and B terminals of the thirteenth transistor Q13.
[0018] It should be noted that when the undervoltage detection circuit is actually working, when the detected voltage is lower than the undervoltage point, Q12 is not turned on, the primary of the optocoupler does not work, and the reported TTL signal is high.
[0019] In this embodiment, the undervoltage detection value is determined by resistors R36, R37, and R38. The undervoltage divider circuit includes a thirty-fourth resistor R34, a thirty-sixth resistor R36, a thirty-seventh resistor R37, a thirty-eighth resistor R38, and a forty-fifth resistor R45. The thirty-sixth resistor R36 and the thirty-seventh resistor R37 are connected in parallel and then connected in series with the thirty-eighth resistor R38 between the positive power input electrode VIN+ and the negative power input electrode VIN-. The thirty-fourth resistor R34 and the forty-fifth resistor R45 are connected in series and then connected in parallel across the thirty-seventh resistor R37. The voltage between the thirty-fourth resistor R34 and the forty-fifth resistor R45 is drawn to the B terminal of the twelfth transistor Q12.
[0020] In the figure, the overvoltage detection circuit includes a fifteenth transistor Q15, a fourteenth MOS transistor Q14, and an overvoltage divider circuit. The E-pole of the fifteenth transistor Q15 is connected to the positive power input electrode VIN+, the C-pole of the fifteenth transistor Q15 is connected to the G-pole of the fourteenth MOS transistor Q14 via the thirty-ninth resistor R39, the positive power input electrode VIN+ is connected to the B-pole of the fifteenth transistor Q15 after being divided by the overvoltage divider circuit, the D-pole of the fourteenth MOS transistor Q14 is connected between the thirty-second resistor R32 and the thirty-third resistor R33, and the S-pole of the fourteenth MOS transistor Q14 is connected to the negative power input electrode VIN-.
[0021] It should be noted that when the detected voltage is higher than the overvoltage point, Q15 conducts, the drain of Q14 is pulled low, Q13 is turned off, the optocoupler primary does not work, and the reported TTL signal is high. When the circuit detects a normal voltage, the optocoupler primary works and the TTL signal is pulled low.
[0022] Specifically, the overvoltage divider circuit includes a 40th resistor R40, a 42nd resistor R42, a 43rd resistor R43, a 44th resistor R44 and a 46th resistor R46, wherein: the 42nd resistor R42 and the 43rd resistor R43 are connected in parallel and then connected in series with the 44th resistor R44 between the positive power input electrode VIN+ and the negative power input electrode VIN-; the 40th resistor R40 and the 46th resistor R46 are connected in series and then connected in parallel at both ends of the 43rd resistor R43, and the voltage between the 40th resistor R40 and the 46th resistor R46 is led to the B pole of the 15th transistor Q15.
[0023] In specific applications, the circuit uses the detected circuit for self-power supply, solving the technical problem that the existing circuit requires independent power supply. When the detected voltage is out of the range, the TTL is reported as a high level, and when the detected voltage is within the range, the TTL is reported as a low level. This circuit has obvious advantages in multi-channel isolated output power supply, good consistency, small size, and high detection accuracy.
[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.
Claims
1. A self-powered over-voltage and under-voltage detection circuit, characterized in that: It includes a photocoupler (U4), an undervoltage detection circuit and an overvoltage detection circuit, wherein: The primary port 1 of the photocoupler (U4) is connected to the positive electrode of the power input (VIN+) through the seventeenth resistor (R17), the primary port 2 of the photocoupler (U4) is connected to the C pole of the thirteenth transistor (Q13), the secondary port 3 of the photocoupler (U4) is connected to the -5V power supply, and the secondary port 4 of the photocoupler (U4) is divided into two paths: one path is connected to the +5V power supply through the eighteenth resistor (R18), and the other path is connected to the signal port (TTL) through the tenth diode (D10) and the nineteenth resistor (R19) connected in parallel; The undervoltage detection circuit includes a twelfth transistor (Q12), a thirteenth transistor (Q13), and an undervoltage divider circuit, wherein the E-pole of the twelfth transistor (Q12) is connected to the positive electrode (VIN+) of the power input, the C-pole of the twelfth transistor (Q12) is connected to the B-pole of the thirteenth transistor (Q13) via a thirty-second resistor (R32) and a thirty-third resistor (R33), the positive electrode (VIN+) of the power input is connected to the B-pole of the twelfth transistor (Q12) after being divided by the undervoltage divider circuit, and the E-pole of the thirteenth transistor (Q13) is connected to the negative electrode (VIN-) of the power input; The overvoltage detection circuit comprises a fifteenth transistor (Q15), a fourteenth MOS transistor (Q14), and an overvoltage divider circuit, wherein the E-pole of the fifteenth transistor (Q15) is connected to the positive electrode (VIN+) of the power input, the C-pole of the fifteenth transistor (Q15) is connected to the G-pole of the fourteenth MOS transistor (Q14) via a thirty-ninth resistor (R39), the positive electrode (VIN+) of the power input is connected to the B-pole of the fifteenth transistor (Q15) after being divided by the overvoltage divider circuit, the D-pole of the fourteenth MOS transistor (Q14) is connected between the thirty-second resistor (R32) and the thirty-third resistor (R33), and the S-pole of the fourteenth MOS transistor (Q14) is connected to the negative electrode (VIN-) of the power input.
2. The self-powered over-voltage and under-voltage detection circuit according to claim 1, characterized in that: An eighth capacitor (C8) is connected between the signal port (TTL) of the photoelectric coupler (U4) and the -5V power supply.
3. The self-powered over-voltage and under-voltage detection circuit according to claim 1, characterized in that: A thirty-fifth resistor (R35) is connected between the E pole and the B pole of the thirteenth transistor (Q13).
4. The self-powered over-voltage and under-voltage detection circuit according to claim 1, characterized in that: The undervoltage divider circuit includes a thirty-fourth resistor (R34), a thirty-sixth resistor (R36), a thirty-seventh resistor (R37), a thirty-eighth resistor (R38) and a forty-fifth resistor (R45), wherein: The thirty-sixth resistor (R36) and the thirty-seventh resistor (R37) are connected in parallel and then connected in series with the thirty-eighth resistor (R38) between the positive power input electrode (VIN+) and the negative power input electrode (VIN-); The thirty-fourth resistor (R34) and the forty-fifth resistor (R45) are connected in series and then connected in parallel to the two ends of the thirty-seventh resistor (R37). The voltage between the thirty-fourth resistor (R34) and the forty-fifth resistor (R45) is led to the B pole of the twelfth transistor (Q12).
5. The self-powered over-voltage and under-voltage detection circuit according to claim 1, characterized in that: The overvoltage divider circuit includes a 40th resistor (R40), a 42nd resistor (R42), a 43rd resistor (R43), a 44th resistor (R44) and a 46th resistor (R46), wherein: The forty-second resistor (R42) and the forty-third resistor (R43) are connected in parallel and then connected in series with the forty-fourth resistor (R44) between the positive power input electrode (VIN+) and the negative power input electrode (VIN-); The 40th resistor (R40) and the 46th resistor (R46) are connected in series and then connected in parallel to the two ends of the 43rd resistor (R43). The voltage between the 40th resistor (R40) and the 46th resistor (R46) is led to the B pole of the 15th transistor (Q15).