Short circuit protection circuit and power supply thereof

Abstract

The utility model discloses an embodiment of a short circuit protection circuit and a power supply thereof, and the circuit comprises a current detection unit, a signal processing unit and a control unit. The current detection unit is used for detecting the load current output by the power supply module, generating and outputting a current sampling signal to the signal processing unit; the signal processing unit is used for amplifying the current sampling signal by a preset multiple, and when the amplified current sampling signal exceeds a preset voltage threshold, generating and outputting a short circuit protection signal to the control unit; the control unit is used for outputting an enable closing signal to the enable pin of the power supply module after a preset time delay in response to the short circuit protection signal, so as to make the power supply module close. In the above manner, the utility model embodiment can solve the problem of short circuit protection inaction caused by wide input range and output range, realize fast and reliable protection of point power supply, and improve the safety and reliability of the power supply system.

Description

Technical Field

[0001] This utility model relates to the field of short circuit protection, and in particular to a short circuit protection circuit and its power supply. Background Technology

[0002] With the rapid development and widespread application of chips, the reliability and safety requirements for power management chips are becoming increasingly stringent. In power systems, short-circuit protection is a crucial function to ensure safe system operation, enabling timely power cut-off upon detection of a short-circuit fault to prevent device damage and safety accidents.

[0003] However, existing chips have some technical shortcomings in short-circuit protection. While their input and output voltage ranges are relatively wide, this wide range design, while improving applicability, also leads to insufficient short-circuit protection accuracy. Specifically, the trigger points for short-circuit and overcurrent protection vary significantly under different power input and load current conditions, lacking consistency and precision.

[0004] More seriously, under certain operating conditions, the short-circuit protection function may fail to activate. This means that when a short-circuit fault occurs at the load end, the chip's internal protection circuitry may fail to respond promptly, causing the short-circuit current to persist. This could lead to device overheating, damage, or even a safety accident. Traditional solutions primarily rely on the chip's internal protection mechanisms, but due to limitations in chip design and variations in manufacturing processes, internal protection often cannot meet the requirements for precise protection. Utility Model Content

[0005] The main technical problem solved by this utility model embodiment is to provide a short-circuit protection circuit and its power supply, which can solve at least some of the defects of existing short-circuit protection circuits.

[0006] In a first aspect, this utility model provides a short-circuit protection circuit, comprising: a current detection unit, a signal processing unit, and a control unit. The current detection unit is connected to a power supply module and the signal processing unit, the signal processing unit is connected to the control unit, and the control unit is also connected to the power supply module. The current detection unit is used to detect the load current output by the power supply module, generate and output a current sampling signal to the signal processing unit. The signal processing unit is used to amplify the current sampling signal by a preset factor, and when the amplified current sampling signal exceeds a preset voltage threshold, generate and output a short-circuit protection signal to the control unit. The control unit is used to respond to the short-circuit protection signal, delay for a preset time, and output an enable / disable signal to the enable pin of the power supply module to turn off the power supply module.

[0007] Optionally, when the preset time is greater than a preset time threshold, a switching unit is further included. The switching unit is connected to the control unit and the power module. The switching unit is used to output a compensation shutdown signal to the compensation pin of the power module in response to the enable shutdown signal, so as to shut down the power module.

[0008] Optionally, the switching unit includes a switching transistor Q1, the gate of which is connected to the output terminal of the control unit, the drain of which is connected to the compensation pin of the power module, and the source of which is connected to reference ground.

[0009] Optionally, the current detection unit includes resistor R4, resistor R5, and capacitor C1; wherein, the first end of resistor R4 is connected to the first end of the current sampling resistor of the power supply module, the first end of resistor R5 is connected to the second end of the current sampling resistor, the second end of resistor R4 is connected to the first end of capacitor C1 and the differential input positive terminal of the signal processing unit, and the second end of resistor R5 is connected to the second end of capacitor C1 and the differential input negative terminal of the signal processing unit.

[0010] Optionally, the signal processing unit includes resistors R2 and R3, and a signal processor U2; wherein, the positive differential input pin of the signal processor U2 is connected to the first output terminal of the signal sampling unit, the negative differential input pin of the signal processor U2 is connected to the second output terminal of the signal sampling unit, the power supply pin of the signal processor U2 is connected to the input power supply, the amplification output pin of the signal processor U2 is connected to the first end of the resistor R2, the comparison input pin of the signal processor U2 is connected to the second end of the resistor R2 and the first end of the resistor R3, the comparison output pin of the signal processor U2 is connected to the input terminal of the control unit, and the ground pin of the signal processor U2 and the second end of the resistor R3 are connected to the reference ground.

[0011] Optionally, the control unit includes a controller U1 and a resistor R1; wherein, the power input pin of the controller U1 is connected to the drive voltage, the control input pin of the controller U1 is connected to the signal output terminal of the signal processing unit, the output terminal of the controller U1 is connected to the second terminal of the resistor R1 and the enable pin of the power module, the ground pin of the controller U1 is connected to the reference ground, and the first terminal of the resistor R1 is connected to the input power supply.

[0012] Optionally, the preset multiple is 20.

[0013] Optionally, the preset voltage threshold is 0.6V.

[0014] Optionally, the preset time threshold is 5µs.

[0015] Secondly, this utility model provides a power supply, including: a power module; and the short-circuit protection circuit described in the first aspect.

[0016] The beneficial effects of this utility model embodiment are: unlike the prior art, this utility model embodiment can solve the problem of short circuit protection not operating due to a wide input and output range, realize fast and reliable protection of the power supply, and improve the safety and reliability of the power supply system. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1 This is a schematic diagram of a short-circuit protection circuit provided by an embodiment of the present invention;

[0019] Figure 2 It shows Figure 1 The circuit structure of the current detection unit and the signal processing unit is shown.

[0020] Figure 3 It shows Figure 1 The circuit structure of the control unit shown;

[0021] Figure 4 This is a schematic diagram of another short-circuit protection circuit provided by an embodiment of the present invention;

[0022] Figure 5 It shows Figure 4 The circuit structure of the control unit and the switching unit is shown. Detailed Implementation

[0023] To facilitate understanding of this utility model, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this specification are for illustrative purposes only.

[0024] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0025] In some embodiments of this application, reference is made to Figure 1 As shown, a basic implementation of a short-circuit protection circuit is provided. The short-circuit protection circuit 10 includes a current detection unit 110, a signal processing unit 120, and a control unit 130.

[0026] The current detection unit 110 is connected to the power supply module 20 and the signal processing unit 120, forming a current signal detection and transmission path. The main function of the current detection unit 110 is to acquire the load current output by the power supply module 20 in real time and convert the load current into a corresponding current sampling signal through an internal current detection mechanism. When the power supply module 20 supplies power to the load, the load current passes through the current detection unit 110, which can accurately capture current changes and convert the current information into an electrical signal.

[0027] Specifically, the current detection unit 110 adopts a non-invasive current detection method, which can acquire accurate current sampling signals without affecting the normal operation of the power module 20. The current sampling signal reflects the real-time status of the load current, including the amplitude change and waveform characteristics of the current. When the load is working normally, the current sampling signal remains within the normal range; when a short circuit fault occurs, the load current increases sharply, and the current sampling signal will also change significantly accordingly.

[0028] The signal processing unit 120 is connected to the current detection unit 110 and the control unit 130. The signal processing unit 120 receives the current sampling signal from the current detection unit 110 and amplifies the received signal by a preset factor. By amplifying the signal, the system's sensitivity to minute current changes is improved, ensuring that even small overcurrent conditions can be accurately detected.

[0029] In some embodiments of this application, the signal processing unit 120 internally includes a signal amplification circuit and a comparison and judgment circuit. The signal amplification circuit amplifies the current sampling signal by a preset factor, resulting in a signal with a higher signal-to-noise ratio and better processing characteristics. The comparison and judgment circuit is responsible for comparing the amplified current sampling signal with a preset voltage threshold. When the amplified current sampling signal exceeds the preset voltage threshold, the comparison and judgment circuit outputs a short-circuit protection signal.

[0030] Setting the preset voltage threshold is a key parameter for the accuracy of the protection system. The preset voltage threshold is set based on the rated current and load characteristics of the power module 20, ensuring that the protection is not falsely triggered during normal operation while also ensuring a timely response to short-circuit faults. When the load current exceeds the safe range, the amplified current sampling signal will exceed the preset voltage threshold, triggering the short-circuit protection mechanism.

[0031] Control unit 130 is connected to signal processing unit 120 and power module 20. Control unit 130 receives short-circuit protection signals from signal processing unit 120 and executes corresponding protection actions according to the state of the short-circuit protection signal. When control unit 130 detects a short-circuit protection signal, it indicates that the system has identified a short-circuit fault and that immediate protection measures are required.

[0032] In some embodiments of this application, the control unit 130, in response to a short-circuit protection signal, outputs an enable / disable signal to the enable pin of the power module 20 after a preset delay. The preset time is set considering the response characteristics of the power module 20 and the stability requirements of the system. The delay time must ensure that the system has sufficient time to confirm the fault state and avoid malfunctions due to momentary interference, while also ensuring that the power supply can be cut off in a timely manner in the event of a real short-circuit fault.

[0033] In some embodiments of this application, the enable / disable signal is a key signal controlling the start / stop state of the power module 20. Upon receiving the enable / disable signal, the enable pin of the power module 20 immediately stops supplying power to the load, thereby cutting off the short-circuit current and protecting the power module 20 and the load from damage caused by short-circuit faults. The enable / disable signal has a fast response characteristic, enabling reliable power shutdown in a short time.

[0034] It is easy to understand that the entire short-circuit protection circuit 10 operates as a closed-loop monitoring and protection process. The current detection unit 110 continuously monitors the load current, the signal processing unit 120 processes and judges the current status in real time, and the control unit 130 executes protection actions based on the judgment results.

[0035] Specifically, when the power module 20 is working normally, the load current remains within a safe range. The current sampling signal output by the current detection unit 110, after being processed by the signal processing unit 120, will not exceed the preset voltage threshold, thus not triggering the short-circuit protection mechanism, and the power module 20 continues to supply power normally. When a short-circuit fault occurs at the load end, the load current increases sharply, and the current detection unit 110 immediately detects the current abnormality and outputs a corresponding current sampling signal.

[0036] After receiving an abnormal current sampling signal, the signal processing unit 120 amplifies the signal by a preset factor to further increase its amplitude, and then compares it with a preset voltage threshold. When the amplified signal exceeds the threshold, the signal processing unit 120 immediately generates a short-circuit protection signal and transmits it to the control unit 130. After receiving the short-circuit protection signal, the control unit 130, after a preset time delay, outputs an enable / disable signal to the enable pin of the power module 20, causing the power module 20 to stop working, thereby realizing the short-circuit protection function.

[0037] In some embodiments of this application, reference is made to Figure 2 As shown, another specific implementation of the short-circuit protection circuit is provided, which provides a detailed circuit design for the internal structure of the current detection unit 110 and the signal processing unit 120.

[0038] In this embodiment, the current detection unit 110 includes resistors R4 and R5 and capacitor C1. Resistors R4 and R5 form the critical path for current sampling, while capacitor C1 provides the necessary filtering function. The first end of resistor R4 is connected to the first end of the current sampling resistor of the power module, establishing an input channel for the current signal. The first end of resistor R5 is connected to the second end of the current sampling resistor, forming another path for differential signal sampling.

[0039] Specifically, the second terminal of resistor R4, the first terminal of capacitor C1, and the positive terminal of the differential input of signal processing unit 120 are connected to form a positive signal transmission path, ensuring that the current sampling signal can be accurately transmitted to signal processing unit 120. At the same time, the addition of capacitor C1 can effectively filter out high-frequency noise and improve signal quality. The second terminal of resistor R5, the second terminal of capacitor C1, and the negative terminal of the differential input of signal processing unit 120 are connected to form a complete differential signal sampling circuit.

[0040] Capacitor C1 plays a crucial filtering role in the current detection unit 110. When a voltage difference occurs across the current sampling resistor, the signal may contain various high-frequency interference components after transmission through resistors R4 and R5. Capacitor C1, through its filtering characteristics, can effectively suppress high-frequency noise, making the signal transmitted to the signal processing unit 120 purer and more stable. The capacitance value of capacitor C1 needs to balance filtering effect and signal response speed, ensuring that noise is filtered out without affecting the fast response characteristics of short-circuit protection.

[0041] In some embodiments of this application, the signal processing unit 120 includes resistors R2 and R3, and a signal processor U2. The signal processor U2 is responsible for amplifying and comparing the current sampling signal. The positive differential input pin of the signal processor U2 is connected to the first output terminal of the current detection unit 110, receiving the positive terminal signal of the differential signal. The negative differential input pin of the signal processor U2 is connected to the second output terminal of the current detection unit 110, receiving the negative terminal signal of the differential signal.

[0042] By using differential input, signal processor U2 can effectively suppress common-mode interference and extract the true current change signal. The positive differential input pin and the negative differential input pin receive two signals from the current detection unit 110, respectively. The differential amplifier circuit inside signal processor U2 amplifies the difference between the two signals.

[0043] Specifically, the power supply pin of signal processor U2 is connected to the input power supply to provide a stable power voltage for the normal operation of signal processor U2. The stability of the power supply directly affects the accuracy and reliability of signal processing; therefore, the input power supply needs to have good voltage regulation characteristics and low ripple characteristics.

[0044] The amplified output pin of signal processor U2 is connected to the first end of resistor R2, establishing an output path for the amplified signal. The amplified output pin outputs a current sampling signal amplified by a preset factor, the amplitude of which is proportional to the original current sampling signal. Resistor R2 plays a role in impedance matching and signal conditioning in the signal transmission path, ensuring that the amplified signal can be accurately transmitted to the subsequent comparison circuit.

[0045] As an example rather than a limitation, the default multiplier is 20x.

[0046] In some embodiments of this application, the comparison input pin of the signal processor U2 is connected to the second end of resistor R2 and the first end of resistor R3, forming an input node for signal comparison. This connection introduces the amplified current sampling signal into the comparison circuit, and simultaneously provides a suitable input level to the comparison circuit through the voltage division effect of resistors R2 and R3. The resistance ratio of resistors R2 and R3 determines the signal amplitude input to the comparison circuit, which needs to be precisely designed according to the requirements of a preset voltage threshold.

[0047] The comparator output pin of signal processor U2 is connected to the input terminal of control unit 130, establishing a transmission channel for the protection signal. When the comparator circuit detects that the input signal exceeds a preset voltage threshold, the comparator output pin outputs a short-circuit protection signal, which is directly transmitted to control unit 130 to trigger subsequent protection actions. The comparator output signal is typically a digital signal, possessing good anti-interference characteristics and transmission reliability.

[0048] As an example rather than a limitation, the preset voltage threshold is 0.6V.

[0049] Specifically, the ground pin of signal processor U2 and the second terminal of resistor R3 are connected to reference ground, providing a stable potential reference for the entire signal processing circuit. The connection of the reference ground ensures that all parts of the circuit have a unified potential reference, avoiding signal distortion or misinterpretation caused by ground potential differences. The second terminal of resistor R3, connected to reference ground, also provides a stable low-potential reference point for the voltage divider circuit.

[0050] As an example, and not a limitation, the signal processor U2 integrates several functional circuits, including a differential amplifier, a comparator, and a reference voltage source. The differential amplifier amplifies the differential input signal by a preset factor, which is selected based on the accuracy requirements of the current detection and the needs of subsequent processing. The comparator compares the amplified signal with an internal reference voltage; when the input signal exceeds the reference voltage, it outputs a high-level short-circuit protection signal.

[0051] In some embodiments of this application, the voltage divider network formed by resistors R2 and R3 plays an important role in signal processing. This voltage divider network not only adjusts the amplitude of the signal input to the comparator but also provides a suitable operating point for the comparator. By adjusting the resistance ratio of resistors R2 and R3, the trigger threshold of the comparator can be flexibly set to adapt to different protection requirements and application scenarios.

[0052] Specifically, when the load current changes, the voltage difference across the current sampling resistor changes accordingly. This voltage difference is transmitted to the signal processor U2 via a sampling circuit consisting of resistors R4 and R5 and capacitor C1. After receiving the differential signal, the signal processor U2 first amplifies it by a preset factor using an internal differential amplifier, and then transmits the amplified signal to the comparator via resistor R2. The comparator compares the received signal with a reference voltage. When the signal amplitude exceeds a preset voltage threshold, it immediately outputs a short-circuit protection signal to the control unit 130, initiating the protection program.

[0053] In some embodiments of this application, reference is made to Figure 3 As shown, a detailed circuit implementation scheme for the control unit 130 in the short-circuit protection circuit is provided. The control unit 130 includes a controller U1 and a resistor R1. The controller U1 is the core component of the control unit 130, possessing integrated functions of signal reception, processing, and output control. The resistor R1, as an auxiliary component, plays an important role in the control circuit for pull-up and signal conditioning.

[0054] Specifically, the power input pin of controller U1 is connected to the drive voltage, providing the necessary power supply for the normal operation of controller U1. The drive voltage needs to meet the operating voltage requirements of controller U1, typically a stable DC voltage with good voltage regulation characteristics and sufficient power capacity. The connection of the power input pin ensures that controller U1 can obtain a stable power supply under various operating conditions, thereby guaranteeing the reliability and stability of the control function.

[0055] The control input pin of controller U1 is connected to the signal output terminal of signal processing unit 120, establishing a receiving channel for protection signals. The control input pin is specifically used to receive short-circuit protection signals from signal processing unit 120. When signal processing unit 120 detects a short-circuit fault and outputs a protection signal, the control input pin immediately receives the signal and transmits it to the control logic circuit inside controller U1. The control input pin has high input impedance and good signal reception characteristics, enabling it to accurately identify changes in the state of the protection signal.

[0056] In some embodiments of this application, the output terminal of the controller U1 is connected to the second terminal of the resistor R1 and the enable pin of the power module 20, forming an output path for the control signal. This connection method enables the controller U1 to directly control the power module 20. When the controller U1 needs to turn off the power module 20, it sends an enable / disable signal through its output terminal, which is simultaneously transmitted to the resistor R1 and the enable pin of the power module 20. The output terminal has sufficient drive capability to provide the control signal required by the enable pin of the power module 20.

[0057] The ground pin of controller U1 is connected to the reference ground, providing a stable potential reference for controller U1. A properly connected reference ground is a fundamental requirement for the normal operation of electronic circuits, ensuring that all functional circuits within controller U1 have a unified potential reference. A good connection of the ground pin also helps improve the circuit's anti-interference performance, reducing signal interference and malfunctions caused by ground potential fluctuations. The reference ground is typically connected to the common ground of the entire system, forming a complete ground network.

[0058] Specifically, the first end of resistor R1 is connected to the input power supply, and the second end of resistor R1 is connected to the output terminal of controller U1 and the enable pin of power module 20. Resistor R1 acts as a pull-up resistor in the control circuit, providing a stable high-level state for the enable pin. When the output terminal of controller U1 is in a high-impedance state or outputs a high level, resistor R1 pulls the enable pin to the input power supply voltage, keeping power module 20 in normal operation. When controller U1 outputs a low level, the enable pin is pulled low, and power module 20 enters the off state.

[0059] The selection of resistor R1 requires consideration of multiple factors, including the input power supply voltage, the output characteristics of controller U1, and the input characteristics of the enable pin of power module 20. The value of resistor R1 must ensure sufficient pull-up current to the enable pin under normal conditions, while also ensuring that excessive pull-up current does not affect the output capability of controller U1 under off conditions. A reasonable resistor value is crucial for achieving reliable control.

[0060] In some embodiments of this application, the controller U1 integrates a complete control logic circuit, including a signal receiving circuit, a logic judgment circuit, and an output driving circuit. The signal receiving circuit is responsible for receiving and processing the short-circuit protection signal from the signal processing unit 120, and has good signal recognition and anti-interference capabilities. The logic judgment circuit executes the corresponding control logic according to the received protection signal status to determine whether to output an enable / disable signal.

[0061] When controller U1 receives a short-circuit protection signal, its internal logic circuit immediately responds and outputs an enable / disable signal to the enable pin of power module 20. However, there is an inherent response delay between the internal chip of power module 20 receiving the enable / disable signal and actually stopping power output. This delay is an inherent characteristic of the internal chip of power module 20, determined by the chip's internal circuit structure and manufacturing process; different models of power chips have different response delay characteristics.

[0062] The enable signal delay time of power module 20 is an inherent parameter in the chip design and manufacturing process, reflecting the time required for the internal control circuit of the chip to change the output state from receiving the enable signal. This delay time is typically in the microsecond range, but there can be significant differences between chips from different manufacturers and models. Some chips may have shorter enable response delays, while others may have relatively longer delays. These differences in delay characteristics directly affect the response speed of short-circuit protection.

[0063] The output driver circuit is responsible for converting the control decisions of the logic judgment circuit into actual output signals. The output driver circuit has sufficient driving capability to quickly change the level state of the output terminal, achieving effective control of the enable pin of the power module 20. The response speed of the output driver circuit is usually much faster than the response delay of the internal chip of the power module 20; therefore, the output response of the controller U1 will not be a limiting factor for the protection system.

[0064] In some embodiments of this application, when the short-circuit protection circuit is working normally, the signal processing unit 120 does not detect a short-circuit fault and therefore does not send a short-circuit protection signal to the controller U1. At this time, the control input pin of the controller U1 is in a normal state, the logic judgment circuit maintains a normal output state, and the output terminal remains at a high level or a high impedance state. Resistor R1 pulls the enable pin up to the input power supply voltage, and the enable pin of the power module 20 receives a high-level signal, maintaining a normal working state.

[0065] When a short-circuit fault occurs at the load end, the signal processing unit 120 detects the abnormal current and immediately outputs a short-circuit protection signal to the control input pin of the controller U1. Upon receiving the protection signal, the controller U1's internal logic judgment circuit immediately identifies the fault state, and the output drive circuit quickly changes the output state, immediately outputting a low-level enable / disable signal. However, from receiving the enable / disable signal to actually stopping power supply, the power module 20 still needs to undergo a preset time delay inherent in its internal chip.

[0066] Specifically, after the enable signal processing circuit of the internal chip of the power module 20 receives the enable / disable signal, it needs to go through multiple steps, including internal signal transmission, logic judgment, and output stage shutdown. Each step requires a certain processing time. The processing time of each step is added together to form the overall response delay time of the power module 20. The length of this delay time directly affects the effectiveness of short-circuit protection. An excessively long delay may result in a longer duration of short-circuit current, increasing the risk of circuit damage.

[0067] In some embodiments of this application, reference is made to Figure 4 As shown, another implementation of the short-circuit protection circuit is provided, which is optimized for the specific operating characteristics of the power module 20. This implementation... Figure 1 Based on the short-circuit protection circuit 10 shown, a switching unit 140 is added according to the response delay characteristics of the power module 20, forming a more complete protection system.

[0068] It is not difficult to understand that this implementation includes Figure 1 The short-circuit protection circuit 10 shown has a basic configuration of a current detection unit 110, a signal processing unit 120, and a control unit 130. The current detection unit 110 is connected to the power supply module 20 and the signal processing unit 120. The signal processing unit 120 is connected to the control unit 130, and the control unit 130 is also connected to the power supply module 20, forming a basic protection control loop.

[0069] Specifically, the current detection unit 110 is used to detect the load current output by the power module 20, and generates and outputs a current sampling signal to the signal processing unit 120. The current detection unit 110 monitors the current changes flowing through the load in real time using a non-invasive current detection method, converting the current information into a corresponding voltage signal. When the load current is within the normal range, the current sampling signal remains stable; when a short-circuit fault causes an abnormal increase in current, the current sampling signal will change accordingly.

[0070] The signal processing unit 120 amplifies the current sampling signal by a preset factor, and generates and outputs a short-circuit protection signal to the control unit 130 when the amplified current sampling signal exceeds a preset voltage threshold. The signal processing unit 120 integrates a signal amplification circuit and a comparison and judgment circuit. It improves the system's sensitivity to current changes by amplifying by a preset factor and achieves accurate identification of fault conditions by comparing with a preset voltage threshold.

[0071] In some embodiments of this application, the control unit 130 is configured to, in response to a short-circuit protection signal, output an enable / disable signal to the enable pin of the power module 20 after a preset time delay, thereby turning off the power module 20. The control unit 130 receives the short-circuit protection signal from the signal processing unit 120, and upon detecting the short-circuit protection signal, immediately outputs an enable / disable signal to the enable pin of the power module 20. However, the power module 20 needs to undergo a preset time delay inherent in its internal chip from receiving the enable / disable signal to actually stopping power supply.

[0072] When the preset time exceeds the preset time threshold, the basic enable control method may not meet the requirements for rapid protection. The preset time threshold is a key parameter for judging the response characteristics of the power module 20 and is used to distinguish the delay characteristics of different types of power modules 20. When the enable signal delay time of the power module 20 exceeds the preset time threshold, it indicates that the response speed of the power module 20 is relatively slow, and a faster protection method is required to ensure system safety.

[0073] Specifically, when the preset time exceeds a preset time threshold, the short-circuit protection circuit 10 also includes a switching unit 140. The switching unit 140 is connected to the control unit 130 and the power module 20, forming an auxiliary protection control channel. The addition of the switching unit 140 provides the system with alternative protection methods. When the main enable control method is not fast enough, the switching unit 140 can achieve a faster protection response through different control paths.

[0074] Switching unit 140, in response to an enable / disable signal, outputs a compensation disable signal to the compensation pin of power module 20, thereby disabling power module 20. The operating principle of switching unit 140 is based on controlling the compensation pin of power module 20, achieving protection by influencing the internal compensation network of power module 20. The compensation pin is typically connected to the loop compensation circuit of power module 20, controlling the stability and dynamic response characteristics of the power supply.

[0075] In some embodiments of this application, a signal transmission relationship is established between the switching unit 140 and the control unit 130, with the switching unit 140 receiving an enable / disable signal from the control unit 130 as a control input. When the control unit 130 detects a short-circuit fault and outputs an enable / disable signal, this signal is transmitted not only to the enable pin of the power module 20 but also to the switching unit 140. Upon receiving the enable / disable signal, the switching unit 140 immediately executes a corresponding switching action, changing the operating state of the compensation pin.

[0076] It is easy to understand that the output of the compensation shutdown signal can quickly affect the operating state of the power module 20. When the switching unit 140 outputs the compensation shutdown signal to the compensation pin, the internal compensation network of the power module 20 is damaged or altered, causing the power supply to lose normal stability control. Although the compensation control method may not be as thorough as direct enable control, its response speed is usually faster, and it can reduce or destabilize the power output in a shorter time, thereby achieving the protection purpose.

[0077] Specifically, the response speed of the switching unit 140 is generally not limited by the enable signal processing delay of the internal chip of the power module 20. The control path of the compensation pin may bypass the enable signal processing circuit, thus enabling a faster response. When the enable signal delay of the power module 20 is long, controlling the compensation pin through the switching unit 140 can affect the power output in a shorter time, improving the overall response speed of the protection system.

[0078] As an example, not a limitation, the preset time threshold is set to 5 microseconds, serving as the dividing line between fast-response and slow-response power modules 20. When the enable signal delay time of power module 20 is no greater than 5 microseconds, the basic enable control method is sufficient to meet the protection requirements, and the system only controls the enable pin through control unit 130. When the enable signal delay time is greater than 5 microseconds, the system automatically adopts a protection scheme including switching unit 140, improving the protection effect through dual control paths.

[0079] When the system detects a short-circuit fault, the control unit 130 immediately outputs an enable / disable signal, simultaneously triggering the switching unit 140. The enable / disable signal controls the power module 20 to shut down via the enable pin, while the compensation / disable signal affects the operating state of the power module 20 via the compensation pin. These two control methods work simultaneously to ensure that the power module 20 stops supplying power to the load in the shortest possible time.

[0080] The addition of the switching unit 140 improves the adaptability of the protection system to different types of power modules 20. Power modules 20 from different manufacturers and models have different internal structures and response characteristics, and a single protection method may not meet the requirements of all application scenarios. By adding the switching unit 140, the system can select the most suitable protection method according to the specific characteristics of the power module 20, thereby improving the reliability and effectiveness of the protection.

[0081] Specifically, when the load is operating normally, the current detection unit 110, signal processing unit 120, and control unit 130 maintain normal monitoring status, while the switching unit 140 remains inactive, thus not affecting the normal operation of the power module 20. When a short-circuit fault occurs, the protection signal is transmitted rapidly, and the control unit 130 and switching unit 140 act simultaneously. Through multiple protection mechanisms, the fault current is ensured to be cut off in time, protecting the power module 20 and the load from damage caused by the short-circuit fault.

[0082] In some embodiments of this application, reference is made to Figure 5 As shown, a detailed circuit implementation scheme for the coordinated operation of the control unit 130 and the switching unit 140 in a short-circuit protection circuit is provided. This embodiment demonstrates that when the enable signal delay time of the power module 20 is greater than a preset time threshold, a faster and more effective short-circuit protection function is achieved through the cooperation of the control unit 130 and the switching unit 140.

[0083] Specifically, the control unit 130 includes a controller U1 and a resistor R1. The controller U1, as the core component of the control unit 130, undertakes the comprehensive functions of signal reception, processing, and output control. The resistor R1, as an important auxiliary component, provides pull-up and signal conditioning functions in the control circuit. Through a reasonable connection configuration, the controller U1 and resistor R1 ensure stable transmission and reliable output of the control signal.

[0084] Specifically, the power input pin of controller U1 is connected to the drive voltage, providing the necessary power guarantee for the stable operation of controller U1. The drive voltage needs to meet the operating voltage specifications of controller U1, and is usually a regulated DC power supply with good voltage stability and sufficient current supply capability.

[0085] The control input pin of controller U1 is connected to the signal output terminal of signal processing unit 120. The control input pin has high input impedance characteristics, which can effectively receive short-circuit protection signals from signal processing unit 120 without affecting the load of the signal source. When signal processing unit 120 detects a short-circuit fault and outputs a protection signal, the control input pin immediately receives the signal and transmits it to the signal processing circuit inside controller U1.

[0086] In some embodiments of this application, the output terminal of the controller U1 is connected to the second terminal of the resistor R1 and the enable pin of the power module 20, and also to the control input terminal of the switching unit 140. This connection method enables the controller U1 to control multiple targets simultaneously. When the controller U1 outputs an enable / disable signal, this signal can be simultaneously transmitted to the enable pin of the power module 20 and the switching unit 140, realizing coordinated action of dual protection control. The output terminal has sufficient driving capability to drive multiple loads simultaneously without affecting signal quality.

[0087] The ground pin of controller U1 is connected to reference ground, providing a unified potential reference for the entire control circuit. A good connection of the ground pin helps reduce the grounding impedance of the circuit, reduces the impact of ground potential fluctuations on the control signal, and improves the system's anti-interference capability and operational reliability.

[0088] Specifically, the first end of resistor R1 is connected to the input power supply, and the second end of resistor R1 is connected to the output of controller U1 and the enable pin of power module 20. Resistor R1 plays an important role as a pull-up resistor in the control circuit, providing a stable high-level state for the enable pin. When the output of controller U1 is in a high-impedance state, resistor R1 ensures that the enable pin is pulled up to the input power supply voltage, maintaining the normal operation of power module 20. When controller U1 outputs a low level, the enable pin is effectively pulled low, triggering the shutdown action of power module 20.

[0089] The switching unit 140 includes a switching transistor Q1. Switching transistor Q1 is typically a MOSFET device, which offers advantages such as fast switching characteristics and low on-resistance. The selection of switching transistor Q1 requires consideration of multiple parameters, including its switching speed, on-resistance, voltage withstand capability, and drive requirements, to ensure that it meets the performance and reliability requirements of the compensation control.

[0090] In some embodiments of this application, the gate of the switching transistor Q1 is connected to the output terminal of the control unit 130, establishing a signal channel for switch control. The gate, as the control terminal of the MOSFET, controls the conduction state between the drain and source through changes in the gate voltage. When the output terminal of the controller U1 outputs a high level, the gate of the switching transistor Q1 receives a high-level signal, causing the switching transistor Q1 to conduct. When the controller U1 outputs a low level, the gate voltage of the switching transistor Q1 decreases, and the switching transistor Q1 enters the off state.

[0091] The drain of the switching transistor Q1 is connected to the compensation pin of the power module 20, forming the execution path for compensation control. The compensation pin is the external connection point of the internal loop compensation network of the power module 20, and is typically connected to components such as compensation capacitors and compensation resistors to adjust the frequency response characteristics and stability of the power supply. When the switching transistor Q1 is turned on, a low-impedance path is formed between the drain and source, effectively pulling the potential of the compensation pin low and disrupting the original compensation network configuration.

[0092] Specifically, the source of the switching transistor Q1 is connected to the reference ground, providing a stable potential reference for Q1. When the switching transistor Q1 is turned on, the resistance between the drain and the source is very small, and the compensation pin is effectively connected to the reference ground through the switching transistor Q1, thereby changing the operating state of the compensation pin.

[0093] As an example and not a limitation, when the short-circuit protection circuit is working normally, the signal processing unit 120 does not detect a short-circuit fault, and the control input pin of the controller U1 receives a normal status signal. At this time, the output of the controller U1 remains at a high level or in a high-impedance state, and the resistor R1 pulls up the enable pin of the power supply module 20 to the input power supply voltage, so that the power supply module 20 maintains normal operation. At the same time, the gate of the switching transistor Q1 also receives the signal status output by the controller U1. Depending on the specific logic design, the switching transistor Q1 may be in the off state, which does not affect the normal operation of the compensation pin.

[0094] In some embodiments of this application, when a short-circuit fault occurs at the load end, the current detection unit 110 detects an abnormal current, and the signal processing unit 120 immediately outputs a short-circuit protection signal to the control input pin of the controller U1. After receiving the protection signal, the controller U1's internal logic circuit responds quickly and changes the level state of the output terminal. The controller U1's output terminal immediately outputs an enable / disable signal, which is simultaneously transmitted to the enable pin of the power module 20 and the gate of the switching transistor Q1.

[0095] The enable / disable signal has a simultaneous effect on the power supply module 20 and the switching unit 140. After the enable pin of the power supply module 20 receives the enable / disable signal, the internal control circuit begins to execute the shutdown procedure. However, due to the inherent delay characteristics of the internal chip of the power supply module 20, the actual shutdown action requires a preset time to complete. At the same time, after receiving the control signal, the gate of the switching transistor Q1 immediately changes its conduction state according to the polarity of the signal.

[0096] Specifically, when the switching transistor Q1 receives the control signal to turn it on, a conduction channel is formed between its drain and source, and the compensation pin is rapidly pulled low to near the reference ground potential. This rapid change in the compensation pin potential immediately affects the operating state of the compensation network inside the power module 20, disrupting the original loop compensation configuration. This disruption of the compensation network causes the power module 20 to lose normal stability control, and the output voltage may oscillate or become unstable, thus indirectly achieving the protection purpose.

[0097] The response speed of the compensation control method is generally faster than that of the enable control method. The switching action of the switching transistor Q1 is only limited by its own switching characteristics and is not affected by the processing delay of the internal chip of the power module 20. Therefore, when the enable signal delay of the power module 20 is long, controlling the compensation pin through the switching transistor Q1 can affect the power output in a shorter time, providing a faster protection response.

[0098] In some embodiments of this application, the synergistic operation of the dual protection mechanisms ensures the high reliability of the protection system. Enable control provides complete shutdown protection, while compensation control provides rapid response protection. The combination of these two protection methods enables the system to possess both rapid response and thorough protection capabilities, adapting to the characteristic requirements of different types of power modules 20 and the protection needs of different application scenarios.

[0099] Unlike existing technologies, this utility model embodiment can solve the problem of short circuit protection failing to operate due to a wide input and output range, achieving fast and reliable protection of the power supply and improving the safety and reliability of the power system.

[0100] Based on the short-circuit protection circuit provided in any of the above embodiments, this application also provides a power supply, which includes a power module and the short-circuit protection circuit provided in any of the above embodiments.

[0101] It should be noted that while the preferred embodiments of this utility model are provided in the specification and accompanying drawings, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are not intended to impose additional limitations on the content of this utility model; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of this utility model. Furthermore, the above-described technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of this utility model specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A short-circuit protection circuit, characterized by comprising: include: The system includes a current detection unit, a signal processing unit, and a control unit. The current detection unit is connected to the power module and the signal processing unit. The signal processing unit is connected to the control unit, and the control unit is also connected to the power module. The current detection unit is used to detect the load current output by the power module, and generate and output a current sampling signal to the signal processing unit; The signal processing unit is used to amplify the current sampling signal by a preset factor, and when the amplified current sampling signal exceeds a preset voltage threshold, it generates and outputs a short-circuit protection signal to the control unit. The control unit is used to respond to the short-circuit protection signal by delaying a preset time to output an enable / disable signal to the enable pin of the power module, so as to turn off the power module.

2. The circuit of claim 1, wherein, When the preset time is greater than the preset time threshold, the system further includes a switching unit, which is connected to the control unit and the power module. The switching unit is used to output a compensation shutdown signal to the compensation pin of the power module in response to the enable shutdown signal, so as to shut down the power module.

3. The circuit according to claim 2, characterized in that, The switching unit includes a switching transistor Q1, the gate of which is connected to the output terminal of the control unit, the drain of which is connected to the compensation pin of the power module, and the source of which is connected to the reference ground.

4. The circuit according to claim 1, characterized in that, The current detection unit includes resistor R4, resistor R5, and capacitor C1; Specifically, the first end of resistor R4 is connected to the first end of the current sampling resistor of the power supply module, the first end of resistor R5 is connected to the second end of the current sampling resistor, the second end of resistor R4 is connected to the first end of capacitor C1 and the positive differential input terminal of the signal processing unit, and the second end of resistor R5 is connected to the second end of capacitor C1 and the negative differential input terminal of the signal processing unit.

5. The circuit according to claim 1, characterized in that, The signal processing unit includes resistors R2 and R3, and a signal processor U2; Specifically, the positive differential input pin of the signal processor U2 is connected to the first output terminal of the signal sampling unit, the negative differential input pin of the signal processor U2 is connected to the second output terminal of the signal sampling unit, the power supply pin of the signal processor U2 is connected to the input power supply, the amplification output pin of the signal processor U2 is connected to the first terminal of the resistor R2, the comparison input pin of the signal processor U2 is connected to the second terminal of the resistor R2 and the first terminal of the resistor R3, the comparison output pin of the signal processor U2 is connected to the input terminal of the control unit, and the ground pin of the signal processor U2 and the second terminal of the resistor R3 are connected to the reference ground.

6. The circuit according to claim 1, characterized in that, The control unit includes a controller U1 and a resistor R1; The power input pin of the controller U1 is connected to the driving voltage, the control input pin of the controller U1 is connected to the signal output terminal of the signal processing unit, the output terminal of the controller U1 is connected to the second terminal of the resistor R1 and the enable pin of the power module, the ground pin of the controller U1 is connected to the reference ground, and the first terminal of the resistor R1 is connected to the input power supply.

7. The circuit according to any one of claims 1-6, characterized in that, The preset multiplier is 20.

8. The circuit according to any one of claims 1-6, characterized in that, The preset voltage threshold is 0.6V.

9. The circuit according to any one of claims 1-6, characterized in that, The preset time threshold is 5µs.

10. A power supply, characterized in that, include: Power module; as well as The short-circuit protection circuit as described in any one of claims 1-9.

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