Overcurrent protection circuit, switching power supply, control method, electronic device, and storage medium

Abstract

The application provides a kind of overcurrent protection circuit, switching power supply, control method, electronic equipment and storage medium, the overcurrent protection circuit includes: current detection module, for detecting load current;Voltage detection module, for detecting the input voltage of load;Feedback adjustment module, for adjusting the output voltage of switching power supply according to the input voltage of load when load current does not reach overcurrent protection threshold;Internal temperature detection module, for detecting the internal temperature of switching power supply;Environment temperature detection module, for detecting the environment temperature where switching power supply is located;Control module, for determining overcurrent protection threshold according to environment temperature and internal temperature, after current detection module detects that load current reaches overcurrent protection threshold, control feedback adjustment module adjusts the output current of switching power supply according to load current.By the present application, overcurrent protection can be triggered in advance when the environment temperature or the internal temperature of switching power supply is too high, to improve safety and reliability.

Description

Technical Field

[0001] This application relates to the field of electronic power technology, and in particular to an overcurrent protection circuit, a switching power supply, a control method, an electronic device, and a storage medium. Background Technology

[0002] A switching power supply, also known as a switching converter or switching power supply, is a high-frequency power conversion device. Its main function is to convert input alternating current (AC) or direct current (DC) into the DC voltage or current required by the user. It is widely used in personal computers, LED lighting, industrial automation equipment, communication equipment, and other fields. To protect the switching power supply and load safety, it is generally designed with an overcurrent protection mechanism, which detects the load current and automatically limits or cuts off the output when the load current exceeds a set value.

[0003] Existing switching power supplies typically use a fixed threshold setting for overcurrent protection, which cannot be adjusted in real time according to the actual operating temperature. This results in the inability to perform overcurrent protection in advance under high-temperature conditions, which in turn leads to a significant reduction in the lifespan and reliability of the switching power supply. Summary of the Invention

[0004] This application provides an overcurrent protection circuit, a switching power supply, a control method, an electronic device, and a storage medium to solve the problem that in the prior art, switching power supplies typically use a fixed threshold setting for overcurrent protection, which cannot be adjusted in real time according to the actual operating temperature. This results in the inability to perform overcurrent protection in advance under high-temperature conditions, leading to a significant reduction in the service life and reliability of the switching power supply.

[0005] In a first aspect, this application provides an overcurrent protection circuit for use in a switching power supply, the overcurrent protection circuit comprising: Current detection module, used to detect load current; A voltage detection module is used to detect the input voltage of the load; A feedback adjustment module, whose input terminal is connected to the output terminal of the voltage detection module and whose output terminal is connected to the switching power supply, is used to adjust the output voltage of the switching power supply according to the input voltage of the load when the load current does not reach the overcurrent protection threshold. An internal temperature detection module is used to detect the internal temperature of the switching power supply; An ambient temperature detection module is used to detect the ambient temperature of the switching power supply. The control module is connected to the internal temperature detection module, the ambient temperature detection module, the current detection module, and the feedback adjustment module, respectively. It is used to determine the overcurrent protection threshold based on the ambient temperature and the internal temperature. After the current detection module detects that the load current reaches the overcurrent protection threshold, it controls the feedback adjustment module to adjust the output current of the switching power supply according to the load current.

[0006] In one possible implementation, the feedback adjustment module includes: A controllable switch, whose input terminal is connected to a voltage source through a first resistor, whose output terminal is grounded, and whose control terminal is connected to the output terminal of the voltage detection module; The first capacitor has its first end connected between the input terminal of the controllable switch and the first resistor, and its second end connected to the output terminal of the voltage detection module. A second capacitor and a second resistor are connected in series, with the second capacitor connected to the input terminal of the controllable switch and the second resistor connected to the output terminal of the voltage detection module; An optocoupler has its first input terminal connected to the voltage source via a third resistor, its second input terminal connected to the input terminals of the control module and the controllable switch, its first output terminal connected to the switching power supply, and its second output terminal connected to reference ground.

[0007] In one possible implementation, the circuit further includes: A diode, the anode of which is connected to the second terminal on the input side of the optocoupler; The fourth resistor has its first end connected to the cathode of the diode and its second end connected to the control module.

[0008] Secondly, this application provides a switching power supply including the overcurrent protection circuit described above.

[0009] Thirdly, this application provides a control method applied to the above-mentioned overcurrent protection circuit, the control method comprising: The overcurrent protection threshold is determined based on the ambient temperature of the switching power supply and the internal temperature of the switching power supply. Determine if the load current has reached the overcurrent protection threshold; If not, the feedback adjustment module is controlled to adjust the output voltage of the switching power supply according to the input voltage of the load; If so, the feedback adjustment module is controlled to adjust the output current of the switching power supply according to the load current.

[0010] In one possible implementation, determining the overcurrent protection threshold based on the ambient temperature of the switching power supply and the internal temperature of the switching power supply includes: The corresponding overcurrent protection threshold is determined based on the ambient temperature of the switching power supply; wherein the overcurrent protection threshold and the ambient temperature satisfy a preset mapping relationship; Determine whether the load current exceeds the overcurrent protection threshold; If not, then determine whether to adjust the overcurrent protection threshold based on the internal temperature of the switching power supply.

[0011] In one possible implementation, determining whether to adjust the overcurrent protection threshold based on the internal temperature of the switching power supply includes: Determine whether the load current is in a stable state; If it is in a stable state, the final stable temperature inside the switching power supply is obtained based on the internal temperature of the switching power supply within a preset time period. Determine whether the final stable temperature is greater than the internal temperature protection threshold; if it is greater, gradually reduce the overcurrent protection threshold until the load current exceeds the overcurrent protection threshold, then trigger the control of the voltage detection module to stop working, and control the feedback adjustment module to adjust the output current of the switching power supply according to the load current; if it is not greater, monitor the change of the ambient temperature and adjust the overcurrent protection threshold according to the change of the ambient temperature. If the system is not in a stable state, the system determines whether to enter over-temperature protection based on the internal temperature of the switching power supply. Then, it monitors the changes in the ambient temperature and adjusts the overcurrent protection threshold accordingly. In the over-temperature protection state, the system controls the switching power supply to operate at the minimum operating current.

[0012] In one possible implementation, adjusting the overcurrent protection threshold based on changes in the ambient temperature includes: Determine whether the change in ambient temperature is greater than a preset threshold. If so, the corresponding overcurrent protection threshold is re-determined based on the ambient temperature. If not, then determine whether to adjust the overcurrent protection threshold based on the internal temperature of the switching power supply.

[0013] In one possible implementation, the gradual reduction of the overcurrent protection threshold is achieved according to the following formula: I th =(1-0.01N)*I0; Wherein, Ith is the adjusted overcurrent protection threshold, I0 is the initial overcurrent protection threshold, and N is the adjustment coefficient, which has an initial value of 0 and increases by 1 each time it is adjusted.

[0014] Fourthly, an electronic device is provided, comprising: a processor and a memory, wherein the processor is configured to execute a control program stored in the memory to implement the above-described control method.

[0015] Fifthly, a storage medium is provided that stores one or more programs, which can be executed by one or more processors to implement the control method described in any one aspect.

[0016] Compared with the prior art, the technical solution provided in this application has the following advantages: The method provided in this application sets up a feedback adjustment module, which is connected to a voltage detection module and a control module respectively, and the control module is connected to a current detection module. When no overcurrent occurs, the feedback adjustment module adjusts the output voltage of the switching power supply according to the input voltage of the load detected by the voltage detection module, so that the switching power supply operates in constant voltage mode; when no overcurrent occurs, the control module controls the feedback adjustment module to adjust the output current of the switching power supply according to the load current detected by the current detection module, so that the switching power supply operates in constant current mode. In addition, an internal temperature detection module and an ambient temperature detection module are also set up to detect the internal temperature of the switching power supply and the ambient temperature where the switching power supply is located. The control module determines the overcurrent protection threshold according to the ambient temperature and the internal temperature of the switching power supply. Considering the situation where the ambient temperature or the internal temperature of the switching power supply is too high, the overcurrent protection threshold is flexibly adjusted, which can trigger overcurrent protection in advance when the ambient temperature or the internal temperature of the switching power supply is too high, avoiding overheating damage to the components inside the switching power supply or load, and improving safety and reliability. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with 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.

[0020] Figure 1 A structural diagram of an overcurrent protection circuit provided in an embodiment of this application; Figure 2 A structural diagram of another overcurrent protection circuit provided in an embodiment of this application; Figure 3 A structural diagram of a switching power supply provided in an embodiment of this application; Figure 4 A flowchart of a control method provided in an embodiment of this application; Figure 5 A flowchart illustrating another control method provided in this application embodiment; Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0023] To protect the safety of switching power supplies and loads, switching power supplies are generally designed with overcurrent protection mechanisms. These mechanisms detect the load current and automatically limit or cut off the output when the load current exceeds a set value. Due to the thermal effect of current, overcurrent generally causes the circuit to heat up. If the ambient temperature is set too high, the internal temperature of the switching power supply will also become too high. If a fixed overcurrent protection threshold is used for control, the temperature at which overcurrent protection is triggered will be extremely high, easily leading to overheating damage to components inside the switching power supply or load. To address the technical problem that existing technologies typically use fixed threshold settings for overcurrent protection, which cannot be adjusted in real time according to the actual operating temperature, resulting in the inability to trigger overcurrent protection early under high-temperature conditions, this application provides an overcurrent protection circuit that can trigger overcurrent protection in advance when the ambient temperature or the internal temperature of the switching power supply is too high, preventing overheating damage to components inside the switching power supply or load, and improving safety and reliability.

[0024] Example 1 Figure 1This is a structural diagram of an overcurrent protection circuit provided in an embodiment of this application. Figure 1 As shown, the overcurrent protection circuit includes: The current detection module 1 has its first input terminal connected to the first end of the sampling resistor, its second input terminal connected to the second end of the sampling resistor, and its output terminal connected to the first terminal of the control module 4. It is used to detect the load current. The sampling resistor is set between the load and the negative terminal of the switching power supply.

[0025] Voltage detection module 2, whose input terminal is connected to the positive terminal of the load, is used to detect the input voltage of the load.

[0026] The feedback adjustment module 3 has its input terminals connected to the output terminal of the voltage detection module 2 and the second terminal of the control module 4, respectively. Its output terminal is connected to the switching power supply. It is used to adjust the output voltage of the switching power supply according to the input voltage of the load when the load current does not reach the overcurrent protection threshold.

[0027] The internal temperature detection module 5 is connected to the third terminal of the control module 4. The internal temperature detection module is used to detect the internal temperature of the switching power supply and output it to the control module 4.

[0028] The ambient temperature detection module 6 is connected to the fourth terminal of the control module 4. The ambient temperature detection module is used to detect the ambient temperature of the switching power supply and output it to the control module 4.

[0029] The control module 4 is used to determine the overcurrent protection threshold based on the ambient temperature and the internal temperature of the switching power supply. After the current detection module 1 detects that the load current has reached the overcurrent protection threshold, the control feedback adjustment module 3 no longer receives the voltage signal from the voltage detection module 2, and the control feedback adjustment module 3 adjusts the output current of the switching power supply according to the load current.

[0030] In this embodiment, the overcurrent protection circuit has a feedback adjustment module connected to both the voltage detection module and the control module, with the control module connected to the current detection module. When no overcurrent occurs, the feedback adjustment module adjusts the output voltage of the switching power supply based on the load input voltage detected by the voltage detection module, ensuring the switching power supply operates in constant voltage mode. When no overcurrent occurs, the control module controls the feedback adjustment module to adjust the output current of the switching power supply based on the load current detected by the current detection module, ensuring the switching power supply operates in constant current mode. Furthermore, an internal temperature detection module and an ambient temperature detection module are included to detect the internal temperature of the switching power supply and the ambient temperature. The control module determines the overcurrent protection threshold based on these temperatures. Considering situations where the ambient temperature or the internal temperature of the switching power supply is too high, the overcurrent protection threshold is flexibly adjusted. This allows for early triggering of overcurrent protection when the ambient temperature or the internal temperature of the switching power supply is too high, preventing overheating damage to components inside the switching power supply or load, and improving safety and reliability.

[0031] Example 2 This embodiment provides another overcurrent protection circuit. Figure 2 A structural diagram of another overcurrent protection circuit provided in the embodiments of this application is shown below. Figure 2 As shown, in order to amplify the voltage signal at a preset frequency, the feedback adjustment module 3 includes: The controllable switch U3 has its input terminal connected to the voltage source VCC through the first resistor R7, its output terminal grounded AGND, and its control terminal connected to the output terminal of the voltage detection module 2.

[0032] The first capacitor C7 has its first end connected between the input terminal of the controllable switch U3 and the first resistor R7, and its second end connected to the output terminal of the voltage detection module 2.

[0033] A second capacitor C8 and a second resistor R11 are connected in series. The second capacitor C8 is connected to the input terminal of the controllable switch U3, and the second resistor R11 is connected to the output terminal of the voltage detection module.

[0034] The first terminal of the optocoupler U2 is connected to the voltage source VCC through the third resistor R6. The second terminal of its input side is connected to the second terminal of the control chip U4 in the control module 4 and the input terminal of the controllable switch U3. The first terminal of its output side is connected to the switching power supply, and the second terminal of its output side is connected to the reference ground GND1.

[0035] To achieve accurate detection of load current, the current detection module 1 includes an operational amplifier U1, whose first input terminal is connected to the first terminal of the sampling resistor R5, its second input terminal is connected to the second terminal of the sampling resistor R5, and its output terminal is connected to the control module 4.

[0036] The load input voltage is relatively high, and directly detecting the load voltage places high demands on the maximum withstand voltage of the detection device. Therefore, it is necessary to divide the load voltage. In order to achieve voltage detection, the voltage detection module includes: a first voltage divider resistor R8 and a second voltage divider resistor R12 connected in series. The first voltage divider resistor R8 is connected to the positive terminal of the load, and the second voltage divider resistor R12 is grounded. The output terminal of the voltage detection module 2 is led out from the first voltage divider resistor R8 and the second voltage divider resistor R12.

[0037] To prevent reverse current flow, the above overcurrent protection circuit also includes: a diode D1, whose anode is connected to the second terminal of the input side of the optocoupler; and a fourth resistor R13, whose first end is connected to the cathode of the diode and whose second end is connected to the second terminal of the control module.

[0038] The overcurrent protection circuit provided in this embodiment can improve the reliability of the switching power supply by predicting the final steady-state temperature of the internal temperature of the switching power supply and combining it with the set ambient temperature-maximum current limiting mapping relationship.

[0039] like Figure 2As shown, the overcurrent protection circuit in this embodiment has 7 pins: output voltage pin VOUT, current sensing cathode VR, current sensing anode AGND, feedback output ground GND1, feedback output pin FB, internal temperature sensing port T1, and ambient temperature sensing port T2. The circuit mainly consists of a voltage detection module (including first voltage divider resistor R8 and second voltage divider resistor R12), a feedback adjustment module (including optocoupler U2, controllable switch U3, third resistor R6, first resistor R7, second resistor R11, first capacitor C7, and second capacitor C8), a current detection module (sampling resistor R5 and operational amplifier U1), and a control circuit (control chip U4, diode D1, and fourth resistor R13). The output voltage pin VOUT of the overcurrent protection circuit is connected to the first end of the first voltage divider resistor R8. Then, the other end of the first voltage divider resistor R8 is connected to one end of the first capacitor C7, one end of the second resistor R11, one end of the second voltage divider resistor R12, and the control terminal of the controllable switch U3, forming node b, which forms a voltage feedback input. One end of the second voltage divider resistor R12 is grounded to the other end of the controllable switch U3. One end of the second capacitor C8 is connected to the other end of the second resistor R11. The other end of the second capacitor C8, the other end of the first capacitor C7, the input terminal of the controllable switch U3, one end of the first resistor R7, and the second pin of the input of the optocoupler U2 are connected to form node c, which forms a feedback response circuit. One end of the third resistor R6 and the other end of the first resistor R7 are connected to the internal voltage source VCC. The other end of the third resistor R6 is connected to the first pin of the input side of the optocoupler U2. The first and second pins of the output side of the optocoupler U2 are connected to the feedback output pin FB and the feedback output ground GND1, respectively. The above devices form an overall voltage feedback loop to ensure that the circuit operates in constant voltage mode.

[0040] The overcurrent protection circuit's current sensing cathode VR and current sensing anode AGND are connected to the two ends of the sampling resistor R5, respectively. Simultaneously, the current sensing cathode VR is connected to the first input terminal of operational amplifier U1, and the current sensing anode AGND is connected to the second input terminal of operational amplifier U1, forming a current sensing input. The output terminal of operational amplifier U1 and the first pin of control chip U4 form a complete current sampling circuit. The third and fourth pins of control chip U4 are connected to the ambient temperature sensing terminal T1 and the internal temperature sensing terminal T2 of the device, respectively, for temperature sensing input. The second pin of control chip U4 is connected in series with the fourth resistor R13 and the cathode of diode D1. The anode of diode D1 is connected to the second pin of the input side of optocoupler U2 in feedback adjustment module 3, forming a current protection action loop. When the current protection is activated, the potential of the second pin of control chip U4 is pulled low, causing the second pin of the input side of optocoupler U2 to be directly connected to the second pin of control chip U4 and controlled by the output signal of the second pin of control chip U4. This shields voltage detection module 2, making the feedback loop dominated by the current and temperature sampling and protection circuit, thus operating in constant current mode.

[0041] Example 3 This embodiment provides a switching power supply. Figure 3 The structural diagram of the switching power supply provided in the embodiments of this application is as follows: Figure 3 As shown, the switching power supply includes the overcurrent protection circuit of the above embodiment, and also includes electrolytic capacitors C2, C3, C4, and C5, which are connected in parallel between the positive and negative terminals of the output side of the switching power supply. The positive terminal of the electrolytic capacitor C5 is connected to the positive terminal of the load to form the output positive terminal.

[0042] like Figure 3As shown, in this embodiment, the live wire and neutral wire are connected to the switching power supply. Four electrolytic capacitors C2, C3, C4, and C5 are connected in parallel between the positive and negative pins of the output side of the switching power supply. The positive terminal of electrolytic capacitor C5 is connected to the positive terminal of the load, forming the positive output terminal. The negative terminal of the load is connected to the current sensing anode AGND in the overcurrent protection circuit, and the negative terminal of capacitor C5 is connected to the current sensing cathode VR in the overcurrent protection circuit, forming the negative output terminal. The positive output terminal is connected to the output voltage pin VOUT of the overcurrent protection circuit, and the feedback output pin FB of the overcurrent protection circuit is connected to the feedback input terminal of the switching power supply, forming a complete voltage sampling feedback loop to achieve normal constant voltage output of the switching power supply. The sampling resistor R5 is set on the negative circuit. The voltage across the sampling resistor R5 is detected and transmitted to the operational amplifier U1 for processing and calculation. The result is then input to the control chip U4 to realize current detection. The internal temperature detection port T1 and the ambient temperature detection port T2 of the overcurrent protection circuit are connected to the internal temperature and ambient temperature sensors, respectively, to realize real-time detection of the internal temperature of the switching power supply and the operating ambient temperature. The control chip U4 is responsible for processing and calculating these input data to control the operation mode of the feedback loop.

[0043] Example 4 This embodiment provides a control method applied to the overcurrent protection circuit of the above embodiment. Figure 4 A flowchart of a control method provided in an embodiment of this application is shown below. Figure 4 As shown, the method includes: S101 determines the overcurrent protection threshold based on the ambient temperature and internal temperature of the switching power supply.

[0044] The internal temperature of the switching power supply is detected by an internal temperature detection module and output to the control module. The ambient temperature of the switching power supply is detected by an ambient temperature detection module and output to the control module. The control module determines the overcurrent protection threshold based on the ambient temperature and the internal temperature of the switching power supply.

[0045] S102, determine whether the load current has reached the overcurrent protection threshold; if not, proceed to step S103; if yes, proceed to step S104.

[0046] In this embodiment, the load current is detected by a current detection module. The first input terminal of the current detection module is connected to the first terminal of the sampling resistor, the second input terminal is connected to the second terminal of the sampling resistor, and the output terminal is connected to the first terminal of the control module. The sampling resistor is set between the load and the negative terminal of the switching power supply.

[0047] S103, the control feedback adjustment module adjusts the output voltage of the switching power supply according to the input voltage of the load.

[0048] In this embodiment, the input voltage of the load is detected by a voltage detection module. The input terminal of the feedback adjustment module is connected to the output terminal of the voltage detection module and the control module, and the output terminal is connected to the switching power supply. When the load current does not reach the overcurrent protection threshold, the feedback adjustment module adjusts the output voltage of the switching power supply according to the input voltage of the load.

[0049] S104, the control feedback adjustment module adjusts the output current of the switching power supply according to the load current.

[0050] After the current detection module detects that the load current has reached the overcurrent protection threshold, the control feedback adjustment module stops receiving voltage signals from the voltage detection module and adjusts the output current of the switching power supply according to the load current.

[0051] The control method in this embodiment detects the internal temperature of the switching power supply using an internal temperature detection module and outputs the result to the control module. It also detects the ambient temperature of the switching power supply using an ambient temperature detection module and outputs the result to the control module. The control module determines an overcurrent protection threshold based on the ambient temperature and the internal temperature of the switching power supply. Considering scenarios where the ambient temperature or the internal temperature of the switching power supply is too high, the control module flexibly adjusts the overcurrent protection threshold. This allows for early triggering of overcurrent protection when either the ambient temperature or the internal temperature of the switching power supply is too high, preventing overheating damage to components within the switching power supply or load, and improving safety and reliability.

[0052] To ensure that the overcurrent protection threshold matches the current ambient temperature and the internal temperature of the switching power supply, and to prevent damage to circuit components due to excessive temperature, the overcurrent protection threshold is determined based on the ambient temperature and the internal temperature of the switching power supply. This includes: determining the corresponding overcurrent protection threshold based on the ambient temperature of the switching power supply; wherein the overcurrent protection threshold and the ambient temperature satisfy a preset mapping relationship; whether the load disconnection current exceeds the overcurrent protection threshold; if not, determining whether to adjust the overcurrent protection threshold based on the internal temperature of the switching power supply.

[0053] If the load current is stable, the steady-state temperature can be fitted based on the internal temperature of the switching power supply. However, if the load current fluctuates excessively, it will lead to excessive temperature fluctuations, making it impossible to fit and determine the steady-state temperature. Therefore, the overcurrent protection threshold needs to be adjusted based on the internal temperature of the switching power supply. This includes: determining whether the load current is stable; if it is stable, obtaining the final stable internal temperature of the switching power supply based on the internal temperature within a preset time period; to accurately control the load current, determining whether the final stable temperature is greater than the internal temperature protection threshold; if it is greater, gradually reducing the overcurrent protection threshold until the load current exceeds the overcurrent protection threshold, then triggering the control voltage detection module to stop working, and the control feedback adjustment module to adjust the output current of the switching power supply according to the load current; if it is not greater, monitoring changes in ambient temperature and adjusting the overcurrent protection threshold accordingly; if it is not stable, determining whether to enter over-temperature protection based on the internal temperature of the switching power supply, then monitoring changes in ambient temperature and adjusting the overcurrent protection threshold accordingly; wherein, in the over-temperature protection state, the switching power supply is controlled to operate at the minimum operating current.

[0054] If the ambient temperature changes significantly, it is obviously inaccurate to apply overcurrent protection based on the overcurrent protection threshold corresponding to the ambient temperature before the change. In order to improve the accuracy of the protection triggering timing, the overcurrent protection threshold is adjusted according to the change in ambient temperature. This includes: determining whether the change in ambient temperature is greater than the preset threshold; if so, re-determining the corresponding overcurrent protection threshold based on the ambient temperature; if not, re-determining whether to adjust the overcurrent protection threshold based on the internal temperature of the switching power supply.

[0055] To achieve a rapid reduction in the overcurrent protection threshold, the reduction step size can be increased after each adjustment of the overcurrent protection threshold. Therefore, the gradual reduction of the overcurrent protection threshold is achieved according to the following formula: I th =(1-0.01N)*I0; Where Ith is the adjusted overcurrent protection threshold, I0 is the initial overcurrent protection threshold, and N is the adjustment coefficient, which has an initial value of 0 and increases by 1 each time it is adjusted.

[0056] Example 5 This embodiment provides another control method. Figure 5 A flowchart of another control method provided in the embodiments of this application is shown below. Figure 5 As shown, the method includes: S1 detects the ambient temperature of the switching power supply.

[0057] S2, Determine the corresponding overcurrent protection threshold I based on the ambient temperature-overcurrent protection threshold mapping table.th And reset the adjustment coefficient N.

[0058] At the start of operation, first detect and record the initial ambient temperature, and then determine the corresponding overcurrent protection threshold I based on the ambient temperature-overcurrent protection threshold mapping table. th .

[0059] S3 detects the load current I.

[0060] S4, judge I<I th Is it true? If yes, proceed to step S9; if no, proceed to step S5.

[0061] S5 executes overcurrent protection and reports a fault warning.

[0062] S6, the control feedback adjustment module adjusts the output current of the switching power supply according to the load current I.

[0063] S7, determine if I < I th Is it true? If yes, proceed to step S8; if no, return to step S6.

[0064] S8 terminates overcurrent protection and eliminates fault warning.

[0065] S9, obtain the internal temperature T of the switching power supply within a preset time t.

[0066] S10, calculate the stability coefficient σ of the load current within a preset time period t.

[0067] S11, determine if the stability coefficient σ < the stability coefficient threshold σ th Is it true? If yes, proceed to step S12; if no, proceed to step S20.

[0068] S12, the steady-state temperature T inside the switching power supply is obtained by fitting the internal temperature T of the switching power supply within a preset time period t. fnl .

[0069] After detecting the load current I, if the load current I < the overcurrent protection value I th The internal temperature and load current I of the switching power supply are continuously recorded within a preset time period t, and the current stability coefficient σ within the preset time period t is calculated to evaluate the degree of current fluctuation within the preset time period t. The current stability coefficient is used in the following ways: ; in, This represents the average value of current data within a preset time period t, where n is the number of current data points. This represents the current data from the i-th detection.

[0070] When the calculated current stability coefficient σ ≤ σth (Stability coefficient threshold) is used to fit the internal temperature T(t) data within a preset time period t. Generally, the temperature rise follows a first-order exponential relationship: ; Among them, T fnl T is the final steady-state temperature, T0 is the initial internal temperature recorded, and τ is the time constant.

[0071] The steady-state temperature is fitted using specific fitting algorithms (such as nonlinear least squares method, linearized difference method, etc.). .

[0072] ， If the load current I > the overcurrent protection value I th If the current limiting protection fails, the entire switching power supply will operate in constant current mode until the current I < I<I0. th This will eliminate the fault warning and restore the constant pressure output mode.

[0073] S13, Determine steady-state temperature T fnl ≤ Maximum temperature threshold T top Is it true? If not, proceed to step S14; if yes, proceed to step S17.

[0074] S14 provides early warning for potential over-temperature protection.

[0075] S15, according to formula I th =(1-0.01N)*I th0 Adjust the overcurrent protection threshold.

[0076] Compare T fnl With T top When T fnl >T top When a potential over-temperature protection warning is issued, N is calculated by accumulating from 0. th =(1-0.01N)*I th0 The current limiting value is adjusted until I < I th Among them, I th0 I is the overcurrent protection threshold in the initial state. th The adjusted overcurrent protection threshold is N, where N is the adjustment coefficient, initially set to 0; when T fnl ≤T top Eliminate the warning in time.

[0077] S16, determine if I < I th Is it true? If not, return to step S15; if yes, proceed to step S18.

[0078] S17 eliminates potential over-temperature protection warnings.

[0079] S18 monitors the ambient temperature changes of the switching power supply.

[0080] S19, Determine the change in ambient temperature. T1 > Preset Threshold T th Is the condition true? If yes, return to step S2; if no, return to step S3.

[0081] Monitoring the ambient temperature of the switching power supply aims to detect significant changes in ambient temperature that could affect the accuracy of the overcurrent protection threshold. T1 > Preset Threshold T th When the ambient temperature changes, the current ambient temperature is updated, and based on the updated ambient temperature, the overcurrent protection value is redefined, and the adjustment coefficient N is reset; when the ambient temperature changes... T1≤Preset threshold T th When the load current I is detected, the next predictive correction cycle begins. The adjustment factor N is not reset to further compensate for environmental factors that may affect temperature rise, other than ambient temperature, thereby increasing reliability.

[0082] S20 monitors the internal temperature T of the switching power supply.

[0083] S21, Determine if the internal temperature T of the switching power supply is less than or equal to the maximum temperature threshold T. top -5 is true; if not, proceed to step S22; if yes, proceed to step S18.

[0084] S22, report over-temperature protection fault, control the output current of the switching power supply to stabilize at the minimum operating current.

[0085] S23, Determine if the internal temperature T of the switching power supply is less than or equal to the maximum temperature threshold T. top -5 is true; if yes, proceed to step S24; if no, return to step S22.

[0086] S24, eliminate the over-temperature protection fault, and then proceed to step S18.

[0087] If the calculated current stability coefficient σ > σth (maximum stability coefficient), it indicates that the load fluctuation is too large. At this time, the fitting prediction is abandoned and internal temperature monitoring is entered. When the internal temperature T > Ttop-5, an over-temperature protection fault is reported and the system directly enters the constant current mode with the minimum operating current until T ≤ Ttop-5, at which point the over-temperature protection fault is eliminated.

[0088] Example 6 This embodiment provides an electronic device, including a processor and a memory, wherein the processor is used to execute a control program stored in the memory to implement the control method of the above embodiment.

[0089] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 6 As shown in the figure, this application provides a device including a processor 111, a communication interface 112, a memory 113, and a communication bus 114, wherein the processor 111, the communication interface 112, and the memory 113 communicate with each other through the communication bus 114. Memory 113 is used to store computer programs; In one embodiment of this application, the processor 111, when executing a program stored in the memory 113, implements the control method provided in any of the foregoing method embodiments.

[0090] Example 7 This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the control method provided in any of the foregoing method embodiments.

[0091] The circuit embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0092] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or of course, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0093] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0094] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An overcurrent protection circuit, applied to a switching power supply, characterized in that, The circuit includes: Current detection module, used to detect load current; A voltage detection module is used to detect the input voltage of the load; A feedback adjustment module, whose input terminal is connected to the output terminal of the voltage detection module and whose output terminal is connected to the switching power supply, is used to adjust the output voltage of the switching power supply according to the input voltage of the load when the load current does not reach the overcurrent protection threshold. An internal temperature detection module is used to detect the internal temperature of the switching power supply; An ambient temperature detection module is used to detect the ambient temperature of the switching power supply. The control module is connected to the internal temperature detection module, the ambient temperature detection module, the current detection module, and the feedback adjustment module, respectively. It is used to determine the overcurrent protection threshold based on the ambient temperature and the internal temperature. After the current detection module detects that the load current reaches the overcurrent protection threshold, it controls the feedback adjustment module to adjust the output current of the switching power supply according to the load current.

2. The circuit according to claim 1, characterized in that, The feedback adjustment module includes: A controllable switch, whose input terminal is connected to a voltage source through a first resistor, whose output terminal is grounded, and whose control terminal is connected to the output terminal of the voltage detection module; The first capacitor has its first end connected between the input terminal of the controllable switch and the first resistor, and its second end connected to the output terminal of the voltage detection module. A second capacitor and a second resistor are connected in series, with the second capacitor connected to the input terminal of the controllable switch and the second resistor connected to the output terminal of the voltage detection module; An optocoupler has its first input terminal connected to the voltage source via a third resistor, its second input terminal connected to the input terminals of the control module and the controllable switch, its first output terminal connected to the switching power supply, and its second output terminal connected to reference ground.

3. The circuit according to claim 2, characterized in that, The circuit also includes: A diode, the anode of which is connected to the second terminal on the input side of the optocoupler; The fourth resistor has its first end connected to the cathode of the diode and its second end connected to the control module.

4. A switching power supply, characterized in that, The overcurrent protection circuit includes any one of claims 1 to 3.

5. A control method applied to the overcurrent protection circuit according to any one of claims 1 to 3, characterized in that, The method includes: The overcurrent protection threshold is determined based on the ambient temperature of the switching power supply and the internal temperature of the switching power supply. Determine if the load current has reached the overcurrent protection threshold; If not, the feedback adjustment module is controlled to adjust the output voltage of the switching power supply according to the input voltage of the load; If so, the feedback adjustment module is controlled to adjust the output current of the switching power supply according to the load current.

6. The method according to claim 5, characterized in that, Determining the overcurrent protection threshold based on the ambient temperature and the internal temperature of the switching power supply includes: The corresponding overcurrent protection threshold is determined based on the ambient temperature of the switching power supply; wherein the overcurrent protection threshold and the ambient temperature satisfy a preset mapping relationship; Determine whether the load current exceeds the overcurrent protection threshold; If not, then determine whether to adjust the overcurrent protection threshold based on the internal temperature of the switching power supply.

7. The method according to claim 6, characterized in that, The step of determining whether to adjust the overcurrent protection threshold based on the internal temperature of the switching power supply includes: Determine whether the load current is in a stable state; If it is in a stable state, the final stable temperature inside the switching power supply is obtained based on the internal temperature of the switching power supply within a preset time period. Determine whether the final stable temperature is greater than the internal temperature protection threshold; if it is greater, gradually reduce the overcurrent protection threshold until the load current exceeds the overcurrent protection threshold, then trigger the control of the voltage detection module to stop working, and control the feedback adjustment module to adjust the output current of the switching power supply according to the load current; if it is not greater, monitor the change of the ambient temperature and adjust the overcurrent protection threshold according to the change of the ambient temperature. If the system is not in a stable state, the system determines whether to enter over-temperature protection based on the internal temperature of the switching power supply. Then, it monitors the changes in the ambient temperature and adjusts the overcurrent protection threshold accordingly. In the over-temperature protection state, the system controls the switching power supply to operate at the minimum operating current.

8. The method according to claim 7, characterized in that, The adjustment of the overcurrent protection threshold based on changes in ambient temperature includes: Determine whether the change in ambient temperature is greater than a preset threshold. If so, the corresponding overcurrent protection threshold is re-determined based on the ambient temperature. If not, then determine whether to adjust the overcurrent protection threshold based on the internal temperature of the switching power supply.

9. The method according to claim 7, characterized in that, The gradual reduction of the overcurrent protection threshold is achieved according to the following formula: I th =(1-0.01N)*I0; Wherein, Ith is the adjusted overcurrent protection threshold, I0 is the initial overcurrent protection threshold, and N is the adjustment coefficient, which has an initial value of 0 and increases by 1 each time it is adjusted.

10. An electronic device, characterized in that, include: A processor and a memory, the processor being configured to execute a control program stored in the memory to implement the control method according to any one of claims 5-9.

11. A storage medium, characterized in that, The storage medium stores one or more programs, which can be executed by one or more processors to implement the control method according to any one of claims 5-9.

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