A short circuit protection circuit and device

Abstract

The application discloses a short-circuit protection circuit and device, when a load is short-circuited, a working voltage is instantaneously pulled down, at this time, a detection voltage output by a voltage division module according to the working voltage is also pulled down, the pulled-down detection voltage is smaller than a protection voltage, a detection module outputs a first control signal to a control module, the control module outputs a protection signal to an output power supply according to the first control signal, so that the output power supply stops outputting the working voltage to the load according to the protection signal, and thus, timely and accurate short-circuit protection is achieved on the load, and the reliability of short-circuit protection is improved.

Description

Technical Field

[0001] This application belongs to the field of electronic circuit technology, and in particular relates to a short-circuit protection circuit and device. Background Technology

[0002] Short circuit faults are a common and seriously hazardous condition in various electronic devices and power systems. During a short circuit, the current in the circuit increases dramatically, potentially causing equipment to overheat, burn out, or even trigger fires and other safety accidents. Existing short circuit protection technologies have some shortcomings, such as insufficient response speed, failing to quickly disconnect the circuit the instant a short circuit occurs, leading to significant equipment damage; and some protection devices lack sensitivity, making them prone to false alarms or missed detections.

[0003] Therefore, a highly reliable short-circuit protection circuit is needed to solve these problems. Utility Model Content

[0004] The purpose of this application is to provide a short-circuit protection circuit that aims to solve the problem of low reliability of traditional short-circuit protection circuits.

[0005] A first aspect of this application provides a short-circuit protection circuit connected to an output power supply, wherein the output power supply outputs a working voltage to a load, comprising: A voltage divider module is used to input the operating voltage and output a detection voltage based on the operating voltage. The detection module, electrically connected to the voltage divider module, is used to output a first control signal when the detected voltage is less than the protection voltage; and The control module, electrically connected to the detection module, is used to output a protection signal to the output power supply when the first control signal is input, so that the output power supply stops outputting the working voltage.

[0006] In one optional implementation, the detection module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, and an optocoupler; The first end of the first resistor is used to input a reference voltage. The second end of the first resistor, the first end of the first capacitor, the first end of the second resistor, and the first end of the third resistor are all connected together. The second end of the second resistor is connected to the secondary input end of the optocoupler. The second end of the third resistor and the first end of the fourth resistor are connected and used to output the first control signal. The primary input end of the optocoupler is used to input the detection voltage. The second end of the first capacitor, the second end of the fourth resistor, and the secondary output end of the optocoupler are connected to the first power supply ground. The primary output end of the optocoupler is connected to the second power supply ground.

[0007] In one optional implementation, the resistance value of the second resistor is in the ohm range.

[0008] In one alternative implementation, the control module includes a first field-effect transistor; The base of the first field-effect transistor is used to input the first control signal, the collector of the first field-effect transistor is used to output the protection signal, and the emitter of the first field-effect transistor is connected to the first power supply ground.

[0009] In one alternative implementation, the first field-effect transistor is a bipolar transistor.

[0010] In one optional implementation, the voltage divider module includes a fifth resistor and a sixth resistor; The first end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is used to input the working voltage, and the second end of the fifth resistor is connected to the second power supply ground.

[0011] In one optional implementation, the protection signal is a low-level signal.

[0012] A second aspect of this application provides a short-circuit protection device, including a short-circuit protection circuit as described in any of the first aspects.

[0013] The beneficial effects of this utility model embodiment compared with the prior art are as follows: When a short circuit occurs in the load, the working voltage is momentarily pulled down. At this time, the detection voltage output by the voltage divider module based on the working voltage will also be pulled down. The pulled-down detection voltage is less than the protection voltage. The detection module outputs a first control signal to the control module. The control module outputs a protection signal to the output power supply based on the first control signal, so that the output power supply stops outputting the working voltage to the load according to the protection signal. This provides timely and accurate short circuit protection for the load and improves the reliability of short circuit protection. Attached Figure Description

[0014] Figure 1 A schematic block diagram of the short-circuit protection circuit provided in the embodiments of this application; Figure 2 A schematic circuit diagram of a short-circuit protection circuit provided in an embodiment of this application. Detailed Implementation

[0015] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0016] Figure 1The diagram illustrates a first example principle block diagram provided by an embodiment of this application. For ease of explanation, only the parts relevant to this embodiment are shown, and are described in detail below: A short-circuit protection circuit is provided, which is connected to an output power supply 200, the output power supply 200 outputting an operating voltage to a load. The short-circuit protection circuit includes a voltage divider module 110, a detection module 120, and a control module 130.

[0017] Voltage divider module 110 is used to input the working voltage and output a detection voltage according to the working voltage; The detection module 120 is electrically connected to the voltage divider module and is used to output a first control signal when the detection voltage is less than the protection voltage. The control module 130 is electrically connected to the detection module 120 and is used to output a protection signal to the output power supply 200 when the first control signal is input, so that the output power supply 200 stops outputting the working voltage.

[0018] In this embodiment, the output power supply 200 outputs a working voltage to the load, which is powered on by the working voltage. When a short circuit occurs in the load, the working voltage is momentarily pulled down. At this time, the detection voltage output by the voltage divider module 110 based on the working voltage is also pulled down. Since the pulled-down detection voltage is less than the protection voltage, the detection module 120 outputs a first control signal to the control module 130. The control module 130 outputs a protection signal to the output power supply 200 based on the first control signal, so that the output power supply 200 stops outputting the working voltage to the load according to the protection signal, thereby providing timely and accurate short-circuit protection for the load and improving the reliability of the short-circuit protection.

[0019] like Figure 2 As shown, in one optional embodiment, the detection module 120 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, and an optocoupler OU1. The first terminal of the first resistor R1 is used to input a reference voltage. The second terminal of the first resistor R1, the first terminal of the first capacitor C1, the first terminal of the second resistor R2, and the first terminal of the third resistor R3 are connected together. The second terminal of the second resistor R2 is connected to the secondary input terminal of the optocoupler OU1. The second terminal of the third resistor R3 and the first terminal of the fourth resistor R4 are connected and used to output the first control signal. The primary input terminal of the optocoupler OU1 is used to input the detection voltage. The second terminal of the first capacitor C1, the second terminal of the fourth resistor R4, and the secondary output terminal of the optocoupler OU1 are connected to the first power supply ground. The primary output terminal of the optocoupler OU1 is connected to the second power supply ground.

[0020] In this embodiment, by setting the first capacitor C1, high-frequency noise can be eliminated, signal interference can be reduced, and the accuracy and stability of the detection module 120 can be improved; by setting the optocoupler OU1, strong and weak current isolation is achieved, the impact of high voltage on the fault side on the low voltage side circuit is reduced, and the overall reliability of the circuit is improved.

[0021] In one optional implementation, the resistance value of the second resistor R2 is in the ohm range, where the ohm range means the resistance value is between 1 and 999 ohms.

[0022] In one alternative implementation, the control module 130 includes a first field-effect transistor Q1; The base of the first field-effect transistor Q1 is used to input the first control signal, the collector of the first field-effect transistor Q1 is used to output the protection signal, and the emitter of the first field-effect transistor Q1 is connected to the first power supply ground.

[0023] In one alternative implementation, the first field-effect transistor Q1 is a bipolar transistor.

[0024] In one optional embodiment, the voltage divider module 110 includes a fifth resistor R5 and a sixth resistor R6; The first end of the fifth resistor R5 is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is used to input the working voltage, and the second end of the fifth resistor R5 is connected to the second power supply ground.

[0025] In one optional implementation, the protection signal is a low-level signal.

[0026] Combination Figure 2 As shown, the implementation process of one specific implementation method is explained.

[0027] When the output is working normally, the operating voltage is normal. The voltage division of the operating voltage by the fifth resistor R5 and the sixth resistor R6 is applied to the primary side of the optocoupler OU1, and this voltage division is greater than the conduction voltage of the primary side of the optocoupler OU1. At this time, the primary side of the optocoupler OU1 is turned on, and the secondary side of the optocoupler OU1 generates a current in the milliampere range. Moreover, the resistance of the second resistor R2 is relatively small, so the voltage division by the second resistor R2 is very small, so the voltage of the first capacitor C1 is also very low. After the voltage division by the third resistor R3 and the fourth resistor R4 in series, the output voltage cannot turn on the first field-effect transistor Q1. Therefore, at this time, the collector of the first field-effect transistor Q1 outputs a high-level signal to the output power supply 200. The output power supply 200 judges that the output is normal based on the high-level signal.

[0028] When the output is short-circuited, the operating voltage is momentarily pulled down. At this time, the voltage applied to the primary side of optocoupler OU1 after the voltage division of the operating voltage by the fifth resistor R5 and the sixth resistor R6 is insufficient to make the primary side of optocoupler OU1 conduct. The secondary side of optocoupler OU1 also becomes non-conducting. At this time, the reference voltage charges the first capacitor C1 instantaneously. The voltage division of the third resistor R3 and the fourth resistor R4 in series also rises instantaneously to become the first control signal. The first control signal makes the first field-effect transistor Q1 conduct. The high-level signal originally output by the collector is changed to a low-level signal (protection signal). The output power supply 200 judges that the output is short-circuited based on the low-level signal, so the output power supply 200 can stop outputting the operating voltage, thereby providing short-circuit protection for the load.

[0029] The short-circuit protection circuit in this embodiment is mainly composed of common electronic components such as optocoupler OU1, transistor, resistor, and capacitor. It does not require expensive dedicated integrated circuits, which reduces design and production costs and facilitates large-scale application. Furthermore, by using component parameters such as voltage divider resistors, it can flexibly adapt to load circuits with different supply voltages, making it suitable for short-circuit protection scenarios of various electronic devices, such as industrial control power supplies and consumer electronics power supply modules.

[0030] The reference voltage can be generated internally by the power management chip of the output power supply 200; the protection signal can be output to the error amplifier compensation pin of the power management chip of the output power supply 200, connected to the output terminal of the internal error amplifier E / A, or the I / O pin of other control chips. The power management chip can be a microcontroller chip such as UC3842, UC3843, UC3844, UC3845, etc. The specific model selected is determined by those skilled in the art based on the description in this application and common general knowledge.

[0031] This application also provides a short-circuit protection device, including the short-circuit protection circuit of any of the above embodiments. Since the short-circuit protection device of this embodiment includes the short-circuit protection circuit of any of the above embodiments, the short-circuit protection device of this embodiment has the beneficial effects corresponding to the short-circuit protection circuit of any of the above embodiments, which will not be repeated here.

[0032] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A short-circuit protection circuit, connected to an output power supply, wherein the output power supply outputs a working voltage to a load, characterized in that, include: A voltage divider module is used to input the operating voltage and output a detection voltage based on the operating voltage. A detection module, electrically connected to the voltage divider module, is used to output a first control signal when the detected voltage is less than the protection voltage. The detection module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, and an optocoupler. The first end of the first resistor is used to input a reference voltage. The second ends of the first resistor, the first ends of the first capacitor, the first ends of the second resistor, and the first ends of the third resistor are all connected together. The second end of the second resistor is connected to the secondary input end of the optocoupler. The second end of the third resistor and the first end of the fourth resistor are connected and used to output the first control signal. The primary input end of the optocoupler is used to input the detected voltage. The second ends of the first capacitor, the second ends of the fourth resistor, and the secondary output end of the optocoupler are connected to a first power supply ground. The primary output end of the optocoupler is connected to a second power supply ground. as well as The control module, electrically connected to the detection module, is used to output a protection signal to the output power supply when the first control signal is input, so that the output power supply stops outputting the working voltage.

2. The short-circuit protection circuit as described in claim 1, characterized in that, The resistance value of the second resistor is in the ohm range.

3. The short-circuit protection circuit as described in claim 1, characterized in that, The control module includes a first field-effect transistor; The base of the first field-effect transistor is used to input the first control signal, the collector of the first field-effect transistor is used to output the protection signal, and the emitter of the first field-effect transistor is connected to the first power supply ground.

4. The short-circuit protection circuit as described in claim 3, characterized in that, The first field-effect transistor is a triode.

5. The short-circuit protection circuit as described in claim 1, characterized in that, The voltage divider module includes a fifth resistor and a sixth resistor; The first end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is used to input the working voltage, and the second end of the fifth resistor is connected to the second power supply ground.

6. The short-circuit protection circuit as described in any one of claims 1-5, characterized in that, The protection signal is a low-level signal.

7. A short-circuit protection device, characterized in that, Includes the short-circuit protection circuit as described in any one of claims 1-5.

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