Power supply protection circuit and equipment

Abstract

The utility model relates to the technical field of power supply circuit protection, in particular to a power supply protection circuit and equipment, the power supply protection circuit optimizes the existing power supply protection mode, and specifically, the circuit comprises an overvoltage protection module, an undervoltage protection module and an overcurrent protection module which are electrically connected in sequence; in addition, a power supply end of an industrial product is electrically connected with the overvoltage protection module and the under-voltage protection module, and the power supply end is electrically connected with a power utilization end of the industrial product through the under-voltage protection module and the overcurrent protection module in sequence. The utility model aims to improve the accuracy of power supply protection detection through the circuit, thereby ensuring the stable operation of industrial products.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply circuit protection, in particular to a power supply protection circuit and equipment. Background Art

[0002] With the continuous advancement of industrial technology, the application fields of industrial products are becoming increasingly extensive, and the requirements for power supply environment are becoming increasingly stringent. Especially in some small workshops with harsh conditions, due to the uneven quality of the power supply equipment used, the output voltage accuracy error is large, which often causes the input voltage of industrial products to exceed the specification range, thereby greatly shortening the service life of the product and increasing the probability of failure.

[0003] At present, the existing power supply protection method mainly uses the overcurrent protection of the fuse or the conduction threshold of the MOS tube for overvoltage or undervoltage protection. However, this solution has many disadvantages. On the one hand, due to the low protection accuracy of the fuse and the MOS tube, it is impossible to provide fast and effective protection for industrial products connected to the power supply equipment; on the other hand, the fuse and the MOS tube are greatly affected by the ambient temperature and have poor stability, which can easily lead to misjudgment or missed judgment.

[0004] In summary, how to improve the accuracy of existing power supply protection detection to ensure the stable operation of industrial products is a technical problem that urgently needs to be solved. Utility Model Content

[0005] The main purpose of the utility model is to provide a power supply protection circuit and equipment, aiming to improve the accuracy of power supply protection detection to ensure the stable operation of industrial products.

[0006] To achieve the above object, the utility model provides a power supply protection circuit, the power supply protection circuit comprising: an overvoltage protection module, an undervoltage protection module and an overcurrent protection module electrically connected in sequence;

[0007] The power supply end of the industrial product is electrically connected to the overvoltage protection module and the undervoltage protection module respectively, and the power supply end is electrically connected to the power consumption end of the industrial product through the undervoltage protection module and the overcurrent protection module in turn;

[0008] The undervoltage protection module is used to access the supply voltage output by the power supply end and perform undervoltage protection after dividing the supply voltage;

[0009] The overvoltage protection module is used to connect the circuit from the undervoltage protection module to the overvoltage protection module after determining that the connected power supply voltage is overvoltage, and to ground the divided voltage output by the undervoltage protection module, wherein the divided voltage is the divided power supply voltage;

[0010] The overcurrent protection module is used to collect the power supply current flowing to the power consumption end through the undervoltage protection module after the circuit connection between the undervoltage protection module and the overcurrent protection module is turned on, and perform overcurrent protection on the power supply current.

[0011] Optionally, the undervoltage protection module includes an undervoltage voltage dividing unit and an undervoltage diagnosis unit which are electrically connected;

[0012] The undervoltage voltage dividing unit is electrically connected to the power supply end and the overvoltage protection module respectively, and the undervoltage diagnosis unit is electrically connected to the power supply end and the overcurrent protection module respectively;

[0013] The undervoltage divider unit is used to divide the connected power supply voltage and output the obtained divided voltage to the undervoltage diagnosis unit so that the undervoltage diagnosis unit can perform undervoltage protection on the divided voltage.

[0014] Optionally, the undervoltage voltage dividing unit includes a first voltage dividing resistor, a second voltage dividing resistor and a first capacitor;

[0015] The second voltage-dividing resistor is connected in parallel with the first capacitor, the first end of the first voltage-dividing resistor is electrically connected to the power supply end, the first end of the second voltage-dividing resistor is electrically connected to the second end of the first voltage-dividing resistor, the undervoltage diagnosis unit and the overvoltage protection module respectively; the second end of the second voltage-dividing resistor is grounded.

[0016] Optionally, the undervoltage diagnosis unit includes: a first MOS tube, a first resistor, a second resistor, a first comparator, a first light emitting diode and a second capacitor;

[0017] The first resistor is connected in parallel with the second capacitor, and the first pin of the first comparator is electrically connected to the first end of the second voltage-dividing resistor;

[0018] The first resistor, the second resistor, the second pin of the first comparator, the third pin of the first comparator and the anode of the first light-emitting diode are connected in series in sequence, and the cathode of the first light-emitting diode is grounded;

[0019] One end of the first resistor connected in series with the second resistor is electrically connected to the gate of the first MOS tube, one end of the first resistor not connected in series with the second resistor is electrically connected to the source of the first MOS tube and the overcurrent protection module, and the drain of the first MOS tube is electrically connected to the power supply end.

[0020] Optionally, the overvoltage protection module includes an overvoltage divider unit and an overvoltage diagnosis unit which are electrically connected;

[0021] The overvoltage voltage dividing unit is electrically connected to the power supply end, and the overvoltage diagnosis unit is electrically connected to the undervoltage protection module;

[0022] The overvoltage divider unit is used to divide the connected power supply voltage and apply it to the overvoltage diagnosis unit for driving, to connect the circuit between the overvoltage diagnosis unit and the undervoltage protection module, and to ground the divided voltage output by the undervoltage protection module.

[0023] Optionally, the overvoltage dividing unit includes a third voltage dividing resistor, a fourth voltage dividing resistor and a third capacitor;

[0024] The third voltage-dividing resistor is connected in series with the fourth voltage-dividing resistor, and the third capacitor is connected in parallel with the fourth voltage-dividing resistor;

[0025] One end of the fourth voltage-dividing resistor connected in series with the third voltage-dividing resistor is electrically connected to the overvoltage diagnosis unit, and one end of the fourth voltage-dividing resistor not connected in series with the third voltage-dividing resistor is grounded.

[0026] Optionally, the overvoltage diagnostic unit includes a second light emitting diode and a second comparator;

[0027] The first pin of the second comparator is electrically connected to the fourth voltage-dividing resistor which is connected in series with one end of the third voltage-dividing resistor;

[0028] The first end of the second voltage-dividing resistor, the second pin of the second comparator, the third pin of the second comparator, and the anode of the second light-emitting diode are electrically connected in sequence, and the cathode of the second light-emitting diode is grounded.

[0029] Optionally, the overcurrent protection module is also electrically connected to the overvoltage protection module;

[0030] The overcurrent protection module includes an overcurrent detection unit and an overcurrent diagnosis unit which are electrically connected. The overcurrent detection unit is electrically connected to the undervoltage protection module, and the overcurrent diagnosis unit is electrically connected to the power consumption end and the overvoltage protection module respectively.

[0031] Optionally, the overcurrent detection unit includes a detection resistor, and the overvoltage protection module includes a second MOS tube, a first transistor, a second transistor, a third resistor, a fourth resistor, a fourth capacitor, a third light-emitting diode and a crystal diode;

[0032] The first end of the detection resistor is electrically connected to the undervoltage protection module and the first end of the third resistor respectively, the second end of the detection resistor is electrically connected to the first end of the fourth resistor and the source of the second MOS tube respectively, the undervoltage protection module is electrically connected to the gate of the second MOS tube, and the drain of the second MOS tube is electrically connected to the power-using end;

[0033] The second end of the third resistor is electrically connected to the emitter of the first triode, and the collector of the first triode is electrically connected to the base of the second triode and the cathode of the third light emitting diode respectively;

[0034] The second end of the fourth resistor is electrically connected to the base of the first transistor and the collector of the second transistor, the first end of the fourth capacitor is electrically connected to the cathode of the third light-emitting diode, and the emitter of the second transistor and the first end of the fourth capacitor are grounded respectively;

[0035] The anode of the third light emitting diode, the first end of the crystal diode, the second end of the crystal diode, and the overvoltage protection module are electrically connected in sequence.

[0036] In addition, to achieve the above-mentioned purpose, the present application also provides a power supply protection device, and the power supply protection device at least includes any of the power supply protection circuits described above.

[0037] The utility model provides a power supply protection circuit that optimizes the fault detection of the existing power supply protection mode. That is, the present application constructs a comprehensive and sophisticated power supply protection circuit by sequentially electrically connecting an overvoltage protection module, an undervoltage protection module, and an overcurrent protection module. The design of this power supply protection circuit can accurately monitor and control the power supply voltage of industrial products, and effectively prevent equipment failure and performance degradation caused by overvoltage, undervoltage, or overcurrent.

[0038] Specifically, the voltage-dividing protection function of the undervoltage protection module of the present application can accurately determine whether the power supply voltage is lower than the preset undervoltage threshold. Once the undervoltage condition is detected, the protection mechanism can be quickly started to ensure the stable operation of the industrial product; and the overvoltage protection module can quickly conduct the circuit connection between the undervoltage protection module and the overcurrent protection module when the power supply voltage is too high, and the divided voltage output after the power supply voltage flows through the undervoltage protection module is grounded, thereby effectively preventing the damage caused by overvoltage to the industrial product. In addition, the present application also designs an overcurrent protection module to further enhance the safety and reliability of the power supply protection circuit. The overcurrent protection module can monitor the power supply current flowing to the power consumption end through the undervoltage protection module in real time. Once the overcurrent condition is detected, the power supply can be quickly cut off to prevent the current overload from causing damage to the industrial product. Compared with the traditional fuse or MOS tube protection scheme, the power supply protection circuit designed in the present application has higher protection accuracy and response speed, can protect the electrical devices of industrial products more quickly, and reduce the possibility of failure. At the same time, the power supply protection circuit designed in the present application is less affected by ambient temperature and can work stably in various harsh environments. When a power failure occurs on site, the power supply protection circuit of the present application can quickly and accurately locate the cause of the failure, which not only reduces the time for troubleshooting, but also effectively improves the accuracy of power supply protection detection, thereby ensuring the stable and reliable operation of industrial products. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the structure of the power supply protection circuit of the present application;

[0040] Figure 2 A schematic diagram of a specific circuit involved in the embodiment of the present application;

[0041] Figure 3 This is a schematic diagram of the undervoltage protection module circuit involved in the embodiment of the present application;

[0042] Figure 4 This is a schematic diagram of an overvoltage protection module circuit involved in an embodiment of the present application;

[0043] Figure 5 This is a schematic diagram of the overcurrent protection module circuit involved in the embodiment of the present application.

[0044] Description of Figure Numbers:

[0045] Label name Label name 100 Power supply protection circuit 10 Overvoltage protection module 20 Undervoltage protection module 30 Overcurrent protection module VCC1 Power supply for industrial products VCC2 Power consumption of industrial products 201 Undervoltage divider unit 202 Undervoltage diagnostic unit Rv1 The first voltage divider resistor Rv2 The second voltage divider resistor C1 First capacitor Q1 The first MOS tube R1 First resistor R2 Second resistor U1 First comparator LED1 First light emitting diode C2 Second capacitor CON1 External input power supply port 101 Overvoltage divider unit 102 Overvoltage diagnostic unit Rv3 The third voltage dividing resistor Rv4 The fourth voltage divider resistor C3 The third capacitor LED2 The second light emitting diode U1 Second comparator 301 Overcurrent detection unit 302 Overcurrent diagnostic unit Ri Sense resistor Q1 The second MOS tube T1 The first transistor T2 The second transistor R3 The third resistor R4 The fourth resistor C4 The fourth capacitor LED3 The third LED D1 Crystal diode

[0046] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0047] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0050] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] In addition, in this application, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0052] Industrial products are applied in more and more fields, and face various industrial power supply environments. Especially in some small workshops with harsh environments, the output voltage accuracy error of the power supply used is large, which is easy to exceed the input voltage specification of industrial products, resulting in a very rapid reduction in product life and many product failures. In addition, when many customers have power failures on site, it is very difficult to determine whether it is a machine problem of the product itself or a power problem without power measurement tools. Through overvoltage and undervoltage detection and diagnosis, the cause of the failure can be quickly located, improving the efficiency of on-site support.

[0053] The existing power supply protection technology solution is to protect against overvoltage or undervoltage through overcurrent protection of fuses or conduction threshold of MOS tubes. However, this existing solution has many disadvantages, such as very poor accuracy, inability to quickly protect devices, being greatly affected by ambient temperature, and difficulty in troubleshooting when a fault occurs. For current automated production equipment (i.e., industrial products), the environmental limitations are high. Once a fault occurs, the troubleshooting time is long, causing great economic losses to customers, affecting customer product experience, and increasing technical support costs.

[0054] In view of the above defects, the utility model proposes a power supply protection circuit and equipment.

[0055] The utility model provides a power supply protection circuit 100, referring to Figure 1 , Figure 1 This is a schematic diagram of a power supply protection circuit of the present application. The power supply protection circuit 100 comprises: an overvoltage protection module 10, an undervoltage protection module 20 and an overcurrent protection module 30 which are electrically connected in sequence;

[0056] The power supply terminal VCC1 of the industrial product is electrically connected to the overvoltage protection module 10 and the undervoltage protection module 20 respectively, and the power supply terminal VCC1 is electrically connected to the power consumption terminal VCC2 of the industrial product through the undervoltage protection module 20 and the overcurrent protection module 30 in turn;

[0057] The undervoltage protection module 20 is used to access the supply voltage output by the power supply terminal VCC1 and perform undervoltage protection after dividing the supply voltage;

[0058] The overvoltage protection module 10 is used to connect the circuit between the undervoltage protection module 20 and the overvoltage protection module 10 after determining that the connected power supply voltage is overvoltage, and to ground the divided voltage output by the undervoltage protection module 20, wherein the divided voltage is the divided power supply voltage;

[0059] The overcurrent protection module 30 is used to collect the power supply current flowing to the power terminal VCC2 through the undervoltage protection module 20 after the circuit connection between the undervoltage protection module 20 and the overcurrent protection module 30 is turned on, and perform overcurrent protection on the power supply current.

[0060] In this embodiment, refer to Figure 2 , Figure 2The specific circuit diagram involved in the embodiment scheme of the present application. The industrial product of the present application is also provided with an electrically connected external input power supply port CON1 and an EMC (Electro Magnetic Compatibility) protection circuit. The power output of the power supply device generally supplies power to the industrial product after being electrically connected to the external input power supply port CON1 and the EMC protection circuit. Specifically, after the undervoltage protection module 20 is connected to the power supply voltage output by the power supply terminal VCC1, the power supply voltage is divided to obtain a divided voltage, and then it can accurately determine whether the power supply voltage is lower than the preset undervoltage threshold. Once the undervoltage condition is detected, the protection mechanism can be quickly started to ensure the stable operation of the industrial product. The overvoltage protection module 10 can monitor the power supply voltage output by the power supply terminal VCC1 in real time. After determining that the power supply voltage is too high, the circuit connection between the undervoltage protection module 20 and the overcurrent protection module 10 can be quickly turned on to ground the divided voltage output after the power supply voltage flows through the undervoltage protection module, thereby effectively preventing the damage caused by overvoltage to the industrial product. In addition, the overcurrent protection module 30 can monitor the power supply current flowing to the power terminal VCC2 through the undervoltage protection module 10 in real time. Once an overcurrent condition is detected, the power supply can be quickly cut off to prevent the current overload from causing damage to the industrial product. In other words, the present application realizes the rapid and accurate positioning of the power failure type of the industrial product through the overvoltage protection module 10, the undervoltage protection module 20 and the overcurrent protection module 30 which are electrically connected in sequence. When the power supply is abnormal, the power supply relationship between the power supply and the industrial product can be quickly cut off to ensure that the industrial product is not damaged, thereby ensuring the stable and reliable operation of the industrial product.

[0061] It should be noted that industrial products include but are not limited to automated production equipment, and this application does not impose any restrictions here.

[0062] In summary, the present application constructs a comprehensive and sophisticated power supply protection circuit 100 by means of an overvoltage protection module 10, an undervoltage protection module 20 and an overcurrent protection module 30 which are electrically connected in sequence. The design of this power supply protection circuit 100 can accurately monitor and control the power supply voltage of industrial products, and effectively prevent equipment failure and performance degradation caused by excessive voltage, too low voltage or excessive current. Specifically, the voltage division protection function of the undervoltage protection module 20 of the present application can accurately determine whether the power supply voltage is lower than the preset undervoltage threshold. Once the undervoltage condition is detected, the protection mechanism can be quickly started to ensure the stable operation of the industrial product; and the overvoltage protection module 30 can quickly conduct the circuit connection between the undervoltage protection module 20 and the overcurrent protection module 30 when the power supply voltage is too high, and the divided voltage output after the power supply voltage flows through the undervoltage protection module 20 is grounded, thereby effectively preventing the damage caused by overvoltage to industrial products. In addition, the present application also designs an overcurrent protection module 30 to further enhance the safety and reliability of the power supply protection circuit 100. The overcurrent protection module 30 can monitor the power supply current flowing to the power consumption terminal VCC2 via the undervoltage protection module 20 in real time. Once an overcurrent condition is detected, the power supply can be quickly cut off to prevent the current overload from causing damage to the industrial product. Compared with the traditional fuse or MOS tube protection scheme, the power supply protection circuit 100 designed in the present application has higher protection accuracy and response speed, can protect the electrical components of industrial products more quickly, and reduce the possibility of failure. At the same time, the power supply protection circuit designed in the present application is less affected by the ambient temperature, can work stably in various harsh environments, and when a power failure occurs on site, the power supply protection circuit 100 of the present application can quickly and accurately locate the cause of the failure, which can not only reduce the time for troubleshooting, but also effectively improve the accuracy of power supply protection detection, thereby ensuring the stable and reliable operation of industrial products.

[0063] Further, in some feasible embodiments, the undervoltage protection module 20 includes an undervoltage voltage dividing unit 201 and an undervoltage diagnosis unit 202 which are electrically connected;

[0064] The undervoltage voltage dividing unit 201 is electrically connected to the power supply terminal VCC1 and the overvoltage protection module 10 respectively, and the undervoltage diagnosis unit 202 is electrically connected to the power supply terminal VCC1 and the overcurrent protection module 30 respectively;

[0065] The undervoltage dividing unit 201 is used to divide the connected power supply voltage and output the obtained divided voltage to the undervoltage diagnosis unit 202 so that the undervoltage diagnosis unit 202 can perform undervoltage protection on the divided voltage.

[0066] Further, in some other feasible embodiments, the undervoltage voltage dividing unit 201 includes a first voltage dividing resistor Rv1, a second voltage dividing resistor Rv2 and a first capacitor C1;

[0067] The second voltage-dividing resistor Rv2 is connected in parallel with the first capacitor C1, the first end of the first voltage-dividing resistor Rv1 is electrically connected to the power supply end VCC1, the first end of the second voltage-dividing resistor Rv2 is electrically connected to the second end of the first voltage-dividing resistor Rv1, the undervoltage diagnosis unit 202 and the overvoltage protection module 10 respectively; the second end of the second voltage-dividing resistor Rv2 is grounded.

[0068] Further, in some feasible embodiments, the undervoltage diagnosis unit 202 includes: a first MOS tube Q1, a first resistor R1, a second resistor R2, a first comparator U1, a first light emitting diode LED1 and a second capacitor C2;

[0069] The first resistor R1 is connected in parallel with the second capacitor C2, and the first pin of the first comparator U1 is electrically connected to the first end of the second voltage-dividing resistor Rv2;

[0070] The first resistor R1, the second resistor R2, the second pin of the first comparator U1, the third pin of the first comparator U1 and the anode of the first light emitting diode LED1 are connected in series in sequence, and the cathode of the first light emitting diode LED1 is grounded;

[0071] One end of the first resistor R1 connected in series with the second resistor R2 is electrically connected to the gate of the first MOS transistor Q1, one end of the first resistor R1 not connected in series with the second resistor R2 is electrically connected to the source of the first MOS transistor Q1 and the overcurrent protection module 10, and the drain of the first MOS transistor Q1 is electrically connected to the power supply terminal VCC1.

[0072] In this embodiment, refer to Figures 2 to 3 , Figure 3The schematic diagram of the circuit of the undervoltage protection module involved in the embodiment of the present application is shown in FIG. The power output of the power supply device is connected to the power supply system of the industrial product through the external input power supply port CON1, and after passing through the EMC protection circuit, the power supply VCC1 is provided to the industrial product through the power supply terminal VCC1 of the industrial product. The power supply VCC1 is divided by the first voltage-dividing resistor Rv1 and the second voltage-dividing resistor Rv2 in the undervoltage voltage-dividing unit 201 to form a divided voltage, which is the opening threshold voltage of the first comparator U1. When the divided voltage exceeds the undervoltage threshold set by the first comparator U1, the first comparator U1 is turned on, and the current flows from the body diode of the first MOS tube Q1 in the undervoltage diagnosis unit 202 through the loop formed by the first resistor R1, the second resistor R2, the first comparator U1 and the first light-emitting diode LED1, enabling the first light-emitting diode LED1 to emit light, and after the first light-emitting diode LED1 emits light, it is determined that the industrial product is in a normal power consumption state, that is, the industrial product is in a normal working state.

[0073] It should be noted that, refer to Figures 2 to 3 ; From Ie*Re=U0, it can be known that the first resistor R1 forms a voltage value, and when this voltage value exceeds the preset threshold voltage of the first MOS transistor Q1 and the first MOS transistor Q2, the first MOS transistor Q1 and the first MOS transistor Q2 are turned on. Wherein, Re is the resistance value of the first resistor R1, Ie refers to the current value flowing through the first resistor R1, and U0 refers to the voltage across the first resistor R1.

[0074] The undervoltage threshold set by the first comparator U1 can be customized according to application requirements, and the undervoltage threshold of 2.5V is a feasible implementation method in the embodiment of the present application, and the present application does not make any limitation here.

[0075] In a specific embodiment, the present application provides an implementation method for achieving undervoltage protection, which is specifically referred to as follows:

[0076] 1. The power supply VCC1 is divided by the first voltage-dividing resistor Rv1 and the second voltage-dividing resistor Rv2. The divided voltage formed on the second voltage-dividing resistor Rv2 is the opening threshold voltage of the first comparator U1. The first capacitor C1 plays a role in preventing false triggering in the circuit and is used for parameter configuration of protection response time and interval. The protection response time can be preliminarily calculated using t=R*C, where t is the protection response time, R is the resistance value of the calculated resistor in parallel with the calculated capacitor, and C is the capacity of the calculated capacitor. The calculated capacitor can be the first capacitor C1, the second capacitor C2, and the third capacitor C3; the calculated resistor can be the second voltage-dividing resistor Rv2, the first resistor R1, and the fourth voltage-dividing resistor Rv4.

[0077] 2. When the voltage of the power supply VCC1 does not exceed the minimum voltage threshold VCCmin (i.e., the undervoltage threshold) set by the first comparator U1, that is, the voltage on the second voltage-dividing resistor Rv2 does not exceed the undervoltage threshold 2.5V of the first comparator U1, the first comparator U1 is not turned on, and the current cannot flow from the body diode of the first MOS tube Q1 through the loop formed by the first resistor R1, the second resistor R2, the first comparator U1 and the first light-emitting diode LED1. The first resistor R1 cannot form a voltage that can turn on the first MOS tube Q1 and the second MOS tube Q2, that is, the gate and source of the first MOS tube Q1 and the second MOS tube Q2 cannot be turned on, forming an undervoltage protection function, that is, the first light-emitting diode LED1 cannot be lit at this time, so as to ensure that the industrial product is not damaged, thereby effectively improving the service life of the industrial product.

[0078] Further, in some feasible embodiments, the overvoltage protection module 10 includes an overvoltage dividing unit 101 and an overvoltage diagnosis unit 102 which are electrically connected;

[0079] The overvoltage dividing unit 101 is electrically connected to the power supply terminal VCC1, and the overvoltage diagnosis unit 102 is electrically connected to the undervoltage protection module 20;

[0080] The overvoltage divider unit 101 is used to divide the connected power supply voltage and apply it to the overvoltage diagnosis unit 102 for driving, to connect the circuit between the overvoltage diagnosis unit 102 and the undervoltage protection module 20, and to ground the divided voltage output by the undervoltage protection module 20.

[0081] Further, in some other feasible embodiments, the overvoltage dividing unit includes a third voltage dividing resistor Rv3, a fourth voltage dividing resistor Rv4 and a third capacitor C3;

[0082] The third voltage-dividing resistor Rv3 is connected in series with the fourth voltage-dividing resistor Rv4, and the third capacitor C3 is connected in parallel with the fourth voltage-dividing resistor Rv4;

[0083] One end of the fourth voltage-dividing resistor Rv4 connected in series with the third voltage-dividing resistor Rv3 is electrically connected to the overvoltage diagnosis unit 102 , and one end of the fourth voltage-dividing resistor Rv4 not connected in series with the third voltage-dividing resistor Rv3 is grounded.

[0084] Further, in some feasible embodiments, the overvoltage diagnosis unit 102 includes a second light emitting diode LED2 and a second comparator U1;

[0085] The first pin of the second comparator U2 is electrically connected to the fourth voltage-dividing resistor Rv4 which is connected in series with one end of the third voltage-dividing resistor Rv3;

[0086] The first end of the second voltage-dividing resistor Rv2, the second pin of the second comparator U2, the third pin of the second comparator U2, and the anode of the second light-emitting diode LED2 are electrically connected in sequence, and the cathode of the second light-emitting diode LED2 is grounded.

[0087] In this embodiment, refer to Figure 2 as well as Figure 4 , Figure 4 This is a schematic diagram of the overvoltage protection module circuit involved in the embodiment of the present application. This application provides an implementation method for implementing the overvoltage protection module, which is specifically referred to as follows:

[0088] 1. When the divided voltage formed on the second voltage-dividing resistor Rv2 exceeds the undervoltage threshold 2.5V of the first comparator U1, the first comparator U1 is turned on, and the current flows from the body diode of the first MOS tube Q1 in the undervoltage diagnosis unit 202 through the loop formed by the first resistor R1, the second resistor R2, the first comparator U1 and the first light-emitting diode LED1. At this time, the first light-emitting diode LED1 continues to remain in a light-emitting state, and a voltage that can turn on the first MOS tube Q1 and the second MOS tube Q2 is formed on the first resistor R1, that is, the gate and source of the first MOS tube Q1 and the second MOS tube Q2 are turned on, forming a power supply VCC2 to power the industrial product.

[0089] 2. If the voltage value of the power supply VCC1 continues to rise, the current of the power supply VCC1 through the third voltage-dividing resistor Rv3 and the fourth voltage-dividing resistor Rv4 increases, that is, the voltage of the fourth voltage-dividing resistor Rv4 continues to rise. When the power supply VCC1 reaches the maximum voltage Vmax limited by the power supply, the voltage of the fourth voltage-dividing resistor Rv4 exceeds the threshold voltage 2.5V of the second comparator U2, and the second comparator U2 is turned on. Constrained by the low on-resistance of the second comparator U2, the voltage formed on the second voltage-dividing resistor Rv2 is pulled down to the ground end, that is, the voltage formed on the second voltage-dividing resistor Rv2 drops sharply to nearly 0V, so that the first comparator U1 cannot be turned on, thereby turning off the light of the first light-emitting diode LED1. At this time, the first resistor R1 cannot form a voltage that can turn on the first MOS tube Q1 and the second MOS tube Q2. The first MOS tube Q1 and the second MOS tube Q2 form an overvoltage protection function. In addition, after the second comparator U2 is turned on, the second light-emitting diode LED2 generates a voltage drop, thereby enabling the second light-emitting diode LED2 to light up.

[0090] Further, in some feasible embodiments, the overcurrent protection module 30 is also electrically connected to the overvoltage protection module 10;

[0091] The overcurrent protection module 30 includes an overcurrent detection unit 301 and an overcurrent diagnosis unit 302 which are electrically connected. The overcurrent detection unit 301 is electrically connected to the undervoltage protection module 20 , and the overcurrent diagnosis unit 302 is electrically connected to the power end and the overvoltage protection module 10 , respectively.

[0092] Further, in some other feasible embodiments, the overcurrent detection unit includes a detection resistor Ri, and the overvoltage protection module includes a second MOS tube Q1, a first transistor T1, a second transistor T2, a third resistor R3, a fourth resistor R4, a fourth capacitor C4, a third light-emitting diode LED3 and a crystal diode D1;

[0093] The first end of the detection resistor Ri is electrically connected to the undervoltage protection module 20 and the first end of the third resistor R3 respectively, the second end of the detection resistor Ri is electrically connected to the first end of the fourth resistor R4 and the source of the second MOS transistor Q2 respectively, the undervoltage protection module 20 is electrically connected to the gate of the second MOS transistor Q2, and the drain of the second MOS transistor Q2 is electrically connected to the power-using end;

[0094] The second end of the third resistor R3 is electrically connected to the emitter of the first transistor T1, and the collector of the first transistor T1 is electrically connected to the base of the second transistor T2 and the cathode of the third light emitting diode LED3 respectively;

[0095] The second end of the fourth resistor R4 is electrically connected to the base of the first transistor T1 and the collector of the second transistor T2, the first end of the fourth capacitor C4 is electrically connected to the cathode of the third light emitting diode LED3, and the emitter of the second transistor T2 and the first end of the fourth capacitor C4 are grounded respectively;

[0096] The anode of the third light emitting diode LED3, the first end of the crystal diode D1, the second end of the crystal diode D1, and the overvoltage protection module 10 are electrically connected in sequence.

[0097] In this embodiment, refer to Figure 2 as well as Figure 5 , Figure 5 This is a schematic diagram of the overcurrent protection module circuit involved in the embodiment of the present application. This application provides an implementation method for overcurrent protection, which is specifically referred to as follows:

[0098] 1. When VCCmin<power supply VCC1 is less than VCCmax, the power supply system of the industrial product is in a normal power supply state. When the current of the detection resistor Ri does not exceed the maximum current Imax of the system, the voltage across the detection resistor Ri does not reach the turn-on voltage of the first transistor T1. At this time, the first transistor T1 is in a cut-off state;

[0099] 2. When the current of the detection resistor Ri exceeds I max, the voltage across the detection resistor Ri exceeds the turn-on voltage of the first transistor T1, the first transistor T1 and the second transistor T2 are turned on successively, and the power supply VCC1 passes through the current loop formed by the third resistor R3, the first transistor T1, the crystal diode D1, the third light-emitting diode LED3 and the fourth voltage-dividing resistor Rv4, enabling the third light-emitting diode LED3 to emit light. At this time, in the current loop formed by the third resistor, the first triode T1, the crystal diode D1, the third light-emitting diode LED3 and the fourth voltage-dividing resistor Rv4, the resistance value of the third resistor R3 is adjusted, so that the voltage formed on the fourth voltage-dividing resistor Rv4 rises rapidly and exceeds the threshold voltage of the second comparator U2, and the threshold voltage of U2 is turned on to change the voltage drop of the second light-emitting diode, so that the second light-emitting diode can emit light; in addition, due to the constraint of the low on-resistance of the second comparator U2, the voltage formed on the second voltage-dividing resistor Rv2 is pulled down to the ground end, so that the first comparator U1 is not turned on, thereby causing the first MOS tube Q1 and the second MOS tube Q2 to be disconnected;

[0100] 3. When the first MOS tube Q1 and the second MOS tube Q2 are disconnected, no current flows through, and there is no voltage drop across the detection resistor Ri. However, the second transistor T2 is already turned on, and the base of the first transistor T1 is pulled to a low potential, so that the first transistor T1 continues to be turned on, forming an interlock, and remains in the overcurrent protection state. The third light-emitting diode LED3 is always on unless the power supply is disconnected externally.

[0101] 4. After the power supply is disconnected externally, the circuit discharges through the third capacitor C3 and the fourth capacitor C4. The time parameters of the third capacitor C3 / fourth capacitor C4 / fourth voltage-dividing resistor Rv4 can be adjusted to achieve the function of interval protection. After the discharge is completed, the power supply can be reconnected to the external input power supply port CON1 to power on again.

[0102] It should be noted that, refer to Figure 2 ,like Figure 2 The first to fourth voltage-dividing resistors Rv1-Rv4, the first to fourth resistors R1-R4 and the detection resistor Ri shown can be discrete resistors; the first to fourth capacitors C1-C4 can be discrete ceramic capacitors; the first to second comparators U1-U2 can be comparators with integrated reference sources; the first to second MOS tubes Q1-Q2 can be N-type MOS tubes, and the first transistor T1 and the second transistor T2 can be PNP transistors.

[0103] In addition, since the accuracy of overcurrent protection will increase with the increase of temperature and the discreteness of the device, the error is large; this application can use a comparator or op amp instead Figure 2The first transistor T1 and the second transistor T2 involved can further reduce the error.

[0104] In summary, due to different industrial product fields, the voltage of power supply for control products may be different, and it is only necessary to adjust the design parameters of different electrical components in the power supply protection circuit to adapt. The power supply protection circuit designed in this application can be used when using a normal specification power supply. When the power supply is abnormal, the cause of the fault can be quickly located according to the detection logic of the power supply protection circuit based on this application, and the power supply relationship between the power supply and the industrial product can be quickly cut off based on the hardware connection of the power supply protection circuit to ensure that the industrial product is not damaged.

[0105] It should be noted that the detection logic based on the power supply protection circuit is as follows:

[0106] 1. When the first light-emitting diode LED1 is on, the second light-emitting diode LED2 is off, and the third light-emitting diode LED3 is off, the power supply system of the industrial product is in normal operation;

[0107] 2. When the first light-emitting diode LED1 is off, the second light-emitting diode LED2 is off, and the third light-emitting diode LED3 is off, the power supply system of the industrial product is in an undervoltage protection state;

[0108] 3. When the first light-emitting diode LED1 is off, the second light-emitting diode LED2 is on, and the third light-emitting diode LED3 is off, the power supply system of the industrial product is in an overvoltage protection state;

[0109] 4. When the first light-emitting diode LED1 is off, the second light-emitting diode LED2 is on, and the third light-emitting diode LED3 is on, the power supply system of the industrial product is in an overcurrent state.

[0110] That is to say, the power supply protection circuit provided by the present application has a high degree of protection effect and reliability, can ensure the stable operation of industrial products in various complex power supply environments, and has important practical application value. When a power failure occurs on site, the power supply protection circuit 100 provided by the present application can quickly locate the cause of the failure and improve the efficiency of on-site support. This can not only reduce the time for troubleshooting and reduce the economic losses of customers, but also improve the product experience of customers and reduce the cost of technical support.

[0111] In addition, the present application also provides a power supply protection device, which includes at least the power supply protection circuit 100 described in any one of the above items.

[0112] In this embodiment, the power supply protection device can be a safety functional circuit device with high precision, fast detection, protection and diagnosis of power supply over-voltage and under-voltage and over-current protection. The power supply protection circuit 100 designed in this application reduces the circuit's dependence on the environment and increases the breadth of industrial applications.

[0113] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural changes made by using the contents of the present application specification and drawings under the technical concept of the present application, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A power supply protection circuit, characterized in that: The power supply protection circuit comprises: an overvoltage protection module, an undervoltage protection module and an overcurrent protection module which are electrically connected in sequence; The power supply end of the industrial product is electrically connected to the overvoltage protection module and the undervoltage protection module respectively, and the power supply end is electrically connected to the power consumption end of the industrial product through the undervoltage protection module and the overcurrent protection module in turn; The undervoltage protection module is used to access the supply voltage output by the power supply end and perform undervoltage protection after dividing the supply voltage; The overvoltage protection module is used to connect the circuit from the undervoltage protection module to the overvoltage protection module after determining that the connected power supply voltage is overvoltage, and to ground the divided voltage output by the undervoltage protection module, wherein the divided voltage is the divided power supply voltage; The overcurrent protection module is used to collect the power supply current flowing to the power consumption end through the undervoltage protection module after the circuit connection between the undervoltage protection module and the overcurrent protection module is turned on, and perform overcurrent protection on the power supply current.

2. The power supply protection circuit according to claim 1, characterized in that: The undervoltage protection module includes an undervoltage voltage dividing unit and an undervoltage diagnosis unit which are electrically connected; The undervoltage voltage dividing unit is electrically connected to the power supply end and the overvoltage protection module respectively, and the undervoltage diagnosis unit is electrically connected to the power supply end and the overcurrent protection module respectively; The undervoltage divider unit is used to divide the connected power supply voltage and output the obtained divided voltage to the undervoltage diagnosis unit so that the undervoltage diagnosis unit can perform undervoltage protection on the divided voltage.

3. The power supply protection circuit according to claim 2, characterized in that: The undervoltage voltage dividing unit includes a first voltage dividing resistor, a second voltage dividing resistor and a first capacitor; The second voltage-dividing resistor is connected in parallel with the first capacitor, the first end of the first voltage-dividing resistor is electrically connected to the power supply end, the first end of the second voltage-dividing resistor is electrically connected to the second end of the first voltage-dividing resistor, the undervoltage diagnosis unit and the overvoltage protection module respectively; the second end of the second voltage-dividing resistor is grounded.

4. The power supply protection circuit according to claim 3, characterized in that: The undervoltage diagnosis unit includes: a first MOS tube, a first resistor, a second resistor, a first comparator, a first light emitting diode and a second capacitor; The first resistor is connected in parallel with the second capacitor, and the first pin of the first comparator is electrically connected to the first end of the second voltage-dividing resistor; The first resistor, the second resistor, the second pin of the first comparator, the third pin of the first comparator and the anode of the first light-emitting diode are connected in series in sequence, and the cathode of the first light-emitting diode is grounded; One end of the first resistor connected in series with the second resistor is electrically connected to the gate of the first MOS tube, one end of the first resistor not connected in series with the second resistor is electrically connected to the source of the first MOS tube and the overcurrent protection module, and the drain of the first MOS tube is electrically connected to the power supply end.

5. The power supply protection circuit according to claim 3, characterized in that: The overvoltage protection module includes an overvoltage divider unit and an overvoltage diagnosis unit which are electrically connected; The overvoltage dividing unit is electrically connected to the power supply end, and the overvoltage diagnosis unit is electrically connected to the undervoltage protection module; The overvoltage divider unit is used to divide the connected power supply voltage and apply it to the overvoltage diagnosis unit for driving, to connect the circuit between the overvoltage diagnosis unit and the undervoltage protection module, and to ground the divided voltage output by the undervoltage protection module.

6. The power supply protection circuit according to claim 5, characterized in that: The overvoltage dividing unit includes a third voltage dividing resistor, a fourth voltage dividing resistor and a third capacitor; The third voltage-dividing resistor is connected in series with the fourth voltage-dividing resistor, and the third capacitor is connected in parallel with the fourth voltage-dividing resistor; One end of the fourth voltage-dividing resistor connected in series with the third voltage-dividing resistor is electrically connected to the overvoltage diagnosis unit, and one end of the fourth voltage-dividing resistor not connected in series with the third voltage-dividing resistor is grounded.

7. The power supply protection circuit according to claim 6, characterized in that: The overvoltage diagnosis unit includes a second light emitting diode and a second comparator; The first pin of the second comparator is electrically connected to the fourth voltage-dividing resistor which is connected in series with one end of the third voltage-dividing resistor; The first end of the second voltage-dividing resistor, the second pin of the second comparator, the third pin of the second comparator, and the anode of the second light-emitting diode are electrically connected in sequence, and the cathode of the second light-emitting diode is grounded.

8. The power supply protection circuit according to claim 1, characterized in that: The overcurrent protection module is also electrically connected to the overvoltage protection module; The overcurrent protection module includes an overcurrent detection unit and an overcurrent diagnosis unit which are electrically connected. The overcurrent detection unit is electrically connected to the undervoltage protection module, and the overcurrent diagnosis unit is electrically connected to the power consumption end and the overvoltage protection module respectively.

9. The power supply protection circuit according to claim 8, characterized in that: The overcurrent detection unit includes a detection resistor, and the overvoltage protection module includes a second MOS tube, a first transistor, a second transistor, a third resistor, a fourth resistor, a fourth capacitor, a third light emitting diode and a crystal diode; The first end of the detection resistor is electrically connected to the undervoltage protection module and the first end of the third resistor respectively, the second end of the detection resistor is electrically connected to the first end of the fourth resistor and the source of the second MOS tube respectively, the undervoltage protection module is electrically connected to the gate of the second MOS tube, and the drain of the second MOS tube is electrically connected to the power-using end; The second end of the third resistor is electrically connected to the emitter of the first triode, and the collector of the first triode is electrically connected to the base of the second triode and the cathode of the third light emitting diode respectively; The second end of the fourth resistor is electrically connected to the base of the first transistor and the collector of the second transistor, the first end of the fourth capacitor is electrically connected to the cathode of the third light-emitting diode, and the emitter of the second transistor and the first end of the fourth capacitor are grounded respectively; The anode of the third light emitting diode, the first end of the crystal diode, the second end of the crystal diode, and the overvoltage protection module are electrically connected in sequence.

10. A power supply protection device, characterized in that: The power supply protection device at least includes the power supply protection circuit as described in any one of claims 1-9.

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