A short-circuit protection circuit and a power conversion circuit

Abstract

This application discloses a short-circuit protection circuit and a power conversion circuit. The short-circuit protection circuit includes: a power supply circuit; a control circuit that receives a first power supply from the power supply circuit and determines the transmission mode of a control signal based on the first power supply; and an output circuit that receives the control signal sent by the control circuit and sends the control signal to a load circuit. When a short circuit occurs in the load circuit, the voltage of the first power supply will periodically decrease gradually to below a set voltage threshold and then gradually increase. When the voltage of the first power supply is below the set voltage threshold, the control circuit will not send a control signal to the output circuit; when the voltage of the first power supply is above the set voltage threshold, it will send a control signal to the output circuit. The short-circuit protection circuit in this application can repeatedly disconnect and reconnect the output supplied to the load circuit when a short circuit occurs in the load circuit, effectively reducing short-circuit losses and lowering the configuration requirements and operating temperature of the components in the short-circuit protection circuit.

Description

Technical Field

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

[0002] Currently, short-circuit faults are a common fault among the various functional circuits of electrical equipment. Therefore, how to provide effective short-circuit protection for various functional circuits has become one of the key issues that cannot be avoided in the field of circuit design.

[0003] However, in existing circuits that provide short-circuit protection, current sampling is usually achieved using resistors. As a result, the short-circuit current becomes extremely large when a short circuit occurs, leading to significant short-circuit losses. Furthermore, the short-circuit power remains constant, placing higher demands on the components in the circuit and resulting in higher operating temperatures, which in turn negatively impacts the lifespan of the components. Summary of the Invention

[0004] This application provides a short-circuit protection circuit and a power conversion circuit. The short-circuit protection circuit can solve the problems of large short-circuit losses and continuous short-circuit power in the prior art, which puts high configuration requirements on the components in the circuit and results in high operating temperature, thus adversely affecting the service life of the components.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is: providing a short-circuit protection circuit, wherein the short-circuit protection circuit includes: a power supply circuit; a control circuit connected to the power supply circuit to receive a first power supply provided by the power supply circuit and determine the transmission mode of the control signal according to the first power supply; and an output circuit connected to the power supply circuit and the control circuit, and used to connect to an external load circuit. The output circuit receives the control signal sent by the control circuit and sends the control signal to the load circuit, so that when a short circuit occurs in the load circuit, the voltage of the first power supply will periodically and gradually decrease to below a set voltage threshold, and then gradually increase to above the set voltage threshold. Wherein, when the voltage of the first power supply is below the set voltage threshold, the control circuit will not send a control signal to the output circuit, and when the voltage of the first power supply is above the set voltage threshold, it will send a control signal to the output circuit.

[0006] The power supply circuit includes a first resistor and a first capacitor. The first end of the first resistor is used to connect to an external first power supply. The second end of the first resistor is connected to the output circuit, the control circuit, and the first end of the first capacitor. The second end of the first capacitor is connected to the control circuit. The first resistor receives the second power supply provided by the first power supply to store or discharge energy in the second power supply through the first resistor and the first capacitor, so as to convert the second power supply into the first power supply.

[0007] The resistance of the first resistor is 10Ω-150Ω.

[0008] The output circuit includes a drive transformer, which includes a primary winding and a secondary winding that are magnetically connected to each other. The first end of the primary winding is connected to the power supply circuit, and the second end of the primary winding is connected to the control circuit. The first and second ends of the secondary winding are respectively used to connect to the first and second ends of the load circuit. The drive transformer receives the control signal sent by the control circuit, converts the control signal, and then sends it to the load circuit.

[0009] The secondary winding includes a first sub-secondary winding and a second sub-secondary winding. The load circuit includes a first sub-load circuit and a second sub-load circuit. The first and second ends of the first sub-secondary winding are respectively used to connect to the first and second ends of the first sub-load circuit. The first and second ends of the second sub-secondary winding are respectively used to connect to the first and second ends of the second sub-load circuit. The drive transformer receives the control signal sent by the control circuit, converts the control signal, and sends it to the first sub-load circuit.

[0010] The output circuit also includes a first diode, the first end of the second sub-secondary winding is connected to the first end of the first diode, the second end of the second sub-secondary winding is connected to the second end of the second sub-load circuit, and the second end of the first diode is connected to the first end of the second sub-load circuit.

[0011] The output circuit also includes a second resistor. The first end of the first sub-secondary winding is connected to the first end of the second resistor, the second end of the first sub-secondary winding is connected to the second end of the first sub-load circuit, and the second end of the second resistor is connected to the first end of the first sub-load circuit.

[0012] The control circuit also includes a driver chip and a first switching transistor. The driver chip is connected to the power supply circuit and the first switching transistor. The first switching transistor is connected to the power supply circuit and the output circuit. The driver chip receives the first power supply provided by the power supply circuit and determines the transmission mode of the control signal according to the first power supply. When it is determined to send the control signal, the driver chip sends the control signal to the first switching transistor. After the first switching transistor adjusts the control signal, it is sent to the output circuit.

[0013] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide a power conversion circuit, wherein the power conversion circuit includes: a buck-boost circuit and a short-circuit protection circuit, the buck-boost circuit is connected to the short-circuit protection circuit and is used to connect an external second power supply and a load circuit, the buck-boost circuit receives a third power supply provided by the second power supply and a control signal sent by the short-circuit protection circuit, and performs voltage conversion on the third power supply according to the control signal to provide the voltage-converted third power supply to the load circuit; wherein the short-circuit protection circuit is the short-circuit protection circuit as described in any of the above claims.

[0014] The step-up / step-down circuit includes a second switching transistor, an inductor, a second diode, a third resistor, and a second capacitor. The first terminal of the second switching transistor is connected to the first terminal of the second power supply. The second terminal of the second switching transistor is connected to the first terminal of the short-circuit protection circuit. The third terminal of the second switching transistor is connected to the second terminal of the short-circuit protection circuit, the first terminal of the inductor, and the second terminal of the second diode. The second terminal of the inductor is connected to the third terminal of the short-circuit protection circuit, the first terminal of the third resistor, the first terminal of the load circuit, the second terminal of the second capacitor, and the fourth terminal of the short-circuit protection circuit. The first terminal of the second diode is connected to the second terminal of the load circuit, the first terminal of the second capacitor, and the fifth terminal of the short-circuit protection circuit. The second terminal of the third resistor is connected to the second terminal of the second power supply.

[0015] The beneficial effects of this application are as follows: Unlike the prior art, the control circuit in the short-circuit protection circuit provided in this application, when receiving the first power supply from the power supply circuit, can determine the transmission method of the control signal according to the first power supply. The output circuit receives the control signal sent by the control circuit and sends the control signal to the load circuit. When a short circuit occurs in the load circuit, the voltage of the first power supply will periodically decrease to below a set voltage threshold and then gradually increase to above the set voltage threshold. When the voltage of the first power supply is below the set voltage threshold, the control circuit will not send a control signal to the output circuit. When the voltage of the first power supply is above the set voltage threshold, it will send a control signal to the output circuit. Thus, when a short circuit occurs in the load circuit, the output supplied to the load circuit can be repeatedly disconnected and reopened, so that the short-circuit protection circuit works intermittently, effectively reducing short-circuit losses and reducing the configuration requirements and operating temperature of each component in the short-circuit protection circuit and the load circuit, thereby avoiding adverse effects on the service life of each component. Moreover, after the short circuit is cleared, the short-circuit protection circuit can automatically and promptly restore the normal power supply to the load circuit, minimizing the impact of the short circuit. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0017] Figure 1 This is a schematic diagram of the structure of the first embodiment of the short-circuit protection circuit of this application;

[0018] Figure 2 This is a schematic diagram of the structure of the second embodiment of the short-circuit protection circuit of this application;

[0019] Figure 3 This is a schematic diagram of the structure of the power conversion circuit of the first embodiment of this application;

[0020] Figure 4 This is a schematic diagram of the second embodiment of the power conversion circuit of this application. Detailed Implementation

[0021] 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 a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] Please see Figure 1 , Figure 1This is a schematic diagram of the structure of the first embodiment of the short-circuit protection circuit of this application. In this embodiment, the short-circuit protection circuit 10 includes: a power supply circuit 11, a control circuit 12, and an output circuit 13.

[0026] The short-circuit protection circuit 10 provided in this application is specifically used in functional circuits that require short-circuit protection, such as non-isolated DC-DC (DC to DC) power supply circuit 11 or any other reasonable circuit with short-circuit risk, so as to minimize the corresponding short-circuit loss when a short circuit occurs and avoid adverse effects on the short-circuit protection circuit 10 and the various devices in the functional circuit. This embodiment does not limit this.

[0027] It is understood that the power supply circuit 11 may specifically have an internally integrated power supply or be connected to an external power supply to obtain a stable power supply from the outside, and after adaptively adjusting the power supply to convert it into a first power supply, it is provided to the control circuit 12.

[0028] Specifically, the control circuit 12 is connected to the power supply circuit 11 to receive the first power supply provided by the power supply circuit 11, thereby enabling the control signal transmission method to be determined based on the first power supply.

[0029] It is worth noting that the transmission method may specifically include the control circuit 12 sending a control signal to the output circuit 13, or not sending a control signal to the output circuit 13, or adjusting the control signal and then sending the adjusted control signal to the output circuit 13. Furthermore, the control circuit 12 specifically determines the current control signal transmission method based on whether the voltage of the first power supply exceeds a set voltage threshold.

[0030] Furthermore, the output circuit 13 is connected to the power supply circuit 11 and the control circuit 12, and is used to connect to the external load circuit 101, so that when the output circuit 13 receives the control signal sent by the control circuit 12, it can send the control signal to the load circuit 101.

[0031] When a short circuit occurs in the load circuit 101, specifically, the two terminals connecting the output circuit 13 and the load circuit 101 are short-circuited, or any reasonable loop in the load circuit 101 is short-circuited, resulting in an abnormally large current at the two terminals connecting the output circuit 13 and the load circuit 101, the load circuit 101 will trigger the voltage of the first power supply to periodically decrease to below a set voltage threshold and then gradually increase to above the set voltage threshold, repeating this cycle until the short circuit in the load circuit 101 is released and the short circuit protection circuit 10 returns to normal operation.

[0032] It is worth noting that the set voltage threshold can be specifically understood as the start-up threshold voltage of the control circuit 12. When the voltage of the first power supply provided by the power supply circuit 11 to the control circuit 12 is lower than the set voltage threshold, the control circuit 12 will stop working and will not send a control signal to the output circuit 13. When the first power supply recovers to a value higher than the set voltage threshold, it will start sending a control signal to the output circuit 13 again.

[0033] In the above scheme, when a short circuit occurs in the load circuit 101, the short circuit protection circuit 10 periodically and gradually reduces the voltage of the first power supply to below a set voltage threshold, and then gradually increases it to above the set voltage threshold. This causes the control circuit 12 to intermittently send control signals to the load circuit 101, thereby causing the short circuit protection circuit 10 to work intermittently. The output circuit 13 intermittently provides output to the load, which can effectively reduce short circuit losses and reduce the configuration requirements and operating temperature of each component in the short circuit protection circuit 10, thereby avoiding adverse effects on the service life of each component.

[0034] Understandably, during the interval when the control circuit 12 does not output a control signal, the short-circuit protection circuit 10 and the load circuit 101 will not generate short-circuit losses. That is, by adjusting the circuit parameters to maximize this interval, short-circuit losses can be effectively reduced. This avoids the risk of damage caused by continuous temperature rise in the components of the short-circuit protection circuit 10 and the load circuit 101 during a short circuit, thus reducing the configuration requirements and operating temperature of the components in the short-circuit protection circuit 10 and preventing adverse effects on their lifespan. After the short circuit is cleared, the short-circuit protection circuit 10 can automatically and promptly restore normal power supply to the load circuit 101, minimizing the impact of the short circuit. Furthermore, the short-circuit protection circuit 10 is simple, reliable, low-cost, and applicable to a wide range of scenarios.

[0035] Please see Figure 2 , Figure 2 This is a schematic diagram of the structure of the second embodiment of the short-circuit protection circuit of this application. This embodiment is based on the first embodiment of the short-circuit protection circuit provided in this application. Specifically, the power supply circuit 21 in the short-circuit protection circuit 20 further includes a first resistor R1 and a first capacitor C1.

[0036] Specifically, the first end of the first resistor R1 is used to connect to the external first power supply VCC, while the second end of the first resistor R1 is connected to the output circuit 23, the control circuit 22 and the first end of the first capacitor C1, and the second end of the first capacitor C1 is connected to the control circuit 22.

[0037] When the first resistor R1 receives the second power supply provided by the first power supply VCC, it can store or discharge the second power supply through the first resistor R1 and the first capacitor C1 to convert the second power supply into the first power supply and provide the first power supply to the control circuit 22.

[0038] Optionally, the second power supply provided by the first power supply VCC can specifically correspond to a DC power supply with any reasonable voltage level that can output stably; this application does not limit this.

[0039] It is worth noting that the first capacitor C1 can be connected in parallel with the control circuit 22, and has the same operating voltage as the control circuit 22. When a short circuit occurs in the load circuit (not shown in the figure), the current flowing through the first resistor R1 will also increase, which will increase the voltage drop through the first resistor R1. The voltage across the first capacitor C1, that is, the voltage of the first power supply, will drop until it is lower than the start-up threshold voltage of the control circuit 22, that is, the set voltage threshold. The control circuit 22 will stop working, and the first capacitor C1 will be charged through the first resistor R1. When the voltage across the first capacitor C1 gradually rises back to exceed the set voltage threshold, it will start again to send a control signal to the output circuit 23. However, if the short circuit is still not cleared at this time, the above process will be repeated, thereby realizing repeated hiccup protection until the short circuit is cleared and the short circuit protection circuit 20 returns to normal.

[0040] Optionally, the resistance value of the first resistor R1 can be 10Ω (ohms) to 150Ω, so as to ensure that the short circuit protection circuit 20 has low loss during normal operation, while maximizing the interval time for the control circuit 22 to stop working when the load circuit is short-circuited, so as to reduce short circuit loss.

[0041] In one embodiment, the output circuit 23 includes a drive transformer T, and the drive transformer T further includes a primary winding Np and a secondary winding (not shown) that are magnetically connected to each other. The first end of the primary winding Np is connected to the power supply circuit 21, and the second end of the primary winding Np is connected to the control circuit 22. The first end and the second end of the secondary winding are respectively used to connect to the first end and the second end of the load circuit, so that when the drive transformer T receives the control signal sent by the control circuit 22, it can convert the control signal and send the converted control signal to the load circuit.

[0042] Understandably, by electrically isolating the power supply circuit 21 and the control circuit 22 from the load circuit through the drive transformer T, it is possible to effectively prevent the power supply circuit 21 and the control circuit 22 from interfering with or damaging the operation of the load circuit.

[0043] Furthermore, in one embodiment, the secondary winding further includes a first sub-secondary winding Ns1 and a second sub-secondary winding Ns2, and the load circuit further includes a first sub-load circuit (not shown) and a second sub-load circuit (not shown). The first end and the second end of the first sub-secondary winding Ns1 are specifically used to connect the first end OUT1+ and the second end OUT1- of the first sub-load circuit, respectively, and the first end and the second end of the second sub-secondary winding Ns2 are used to connect the first end OUT+ and the second end OUT- of the second sub-load circuit, respectively.

[0044] Specifically, when the drive transformer T receives the control signal sent by the control circuit 22, it converts the control signal and then sends it to the first sub-load circuit.

[0045] In one embodiment, the output circuit 23 further includes a first diode D1, the first end of the second sub-side winding Ns2 is specifically connected to the first end of the first diode D1, the second end of the second sub-side winding Ns2 is connected to the second end OUT- of the second sub-load circuit, and the second end of the first diode D1 is connected to the first end OUT+ of the second sub-load circuit.

[0046] Understandably, when a short circuit occurs in the load circuit, specifically when the first terminal OUT+ of the second sub-load circuit is shorted to its second terminal, the voltage of the second sub-secondary winding Ns2 will be clamped to the forward conduction voltage of the first diode D1, which is equivalent to a short circuit. This increases the current flowing through the second sub-secondary winding Ns2, and consequently increases the current flowing through the primary winding Np.

[0047] In one embodiment, the output circuit 23 in the short-circuit protection circuit 20 further includes a second resistor R2, and the first end of the first sub-secondary winding Ns1 is specifically connected to the first end of the second resistor R2, the second end of the first sub-secondary winding Ns1 is connected to the second end OUT1- of the first sub-load circuit, and the second end of the second resistor R2 is connected to the first end OUT1+ of the first sub-load circuit.

[0048] Specifically, the first sub-load circuit can be a step-up / step-down circuit. When the control circuit 22 sends a control signal to the first sub-load circuit through the output circuit 23, the on / off state of the corresponding switching devices in the step-up / step-down circuit can be adjusted through the control signal to regulate the voltage conversion of the step-up / step-down circuit.

[0049] In one embodiment, the control circuit 22 in the short-circuit protection circuit 20 further includes a driver chip IC and a first switch Q1. The driver chip IC is specifically connected to the power supply circuit 21 and the first switch Q1, while the first switch Q1 is connected to the power supply circuit 21 and the output circuit 23.

[0050] Specifically, when the driver chip IC receives the first power supply provided by the power supply circuit 21, it determines the transmission method of the control signal based on the first power supply. When it is determined that the voltage of the first power supply is higher than the set voltage threshold, it sends the control signal to the first switch transistor Q1. After the first switch transistor Q1 adjusts the control signal, the adjusted control signal is sent to the output circuit 23.

[0051] Understandably, the set voltage threshold specifically corresponds to the start-up threshold voltage or holding voltage of the driver chip IC, and the control signal specifically corresponds to a PWM (Pulse Width Modulation) signal, so as to determine whether to issue a PWM signal and / or adjust the duty cycle of the PWM signal by using the voltage magnitude of the first power supply and the sampling current fed back to the control chip by the load circuit.

[0052] Alternatively, the driver chip IC can be replaced by any reasonable circuit with signal processing function, such as an MCU (Microcontroller Unit) circuit, and this application does not limit it in this regard.

[0053] It is worth noting that the working principle of the short circuit protection circuit 20 can be specifically described as follows: after the first power supply VCC is powered, the first power supply VCC will supply power to the driver chip IC through the first resistor R1 and the first capacitor C1. When the voltage of the first power supply provided to the driver chip IC is higher than the start-up threshold voltage of the driver chip IC, the driver chip IC has a PWM signal output, that is, it sends out a control signal to the outside.

[0054] In this circuit, the second secondary winding Ns2 of the drive transformer T is connected in parallel to the first terminal OUT+ and the second terminal OUT- of the second sub-load circuit through the first diode D1. That is, the cathode of the first diode D1 is connected to the first terminal OUT+ of the second sub-load circuit, while the other end of the second secondary winding Ns2 is connected to the second terminal OUT- of the second sub-load circuit.

[0055] Understandably, when the voltage generated by the second sub-secondary winding Ns2 is lower than the voltage between the first terminal OUT+ and the second terminal OUT- of the second sub-load circuit for main power output, the other winding of the drive transformer T, i.e., the first sub-secondary winding Ns1, will send a PWM signal to the first sub-load circuit through the second resistor R2 to drive the switching transistor inside the first sub-load circuit. Conversely, when a short circuit occurs in the second sub-load circuit, i.e., when the first terminal OUT+ and the second terminal OUT- of the second sub-load circuit are shorted, a PWM signal will be sent through the sampling resistor in the second sub-load circuit (not shown in the figure). The output signal is generated to achieve wave-by-wave current limiting, and the driver chip IC will continuously emit PWM signals. However, since the second sub-secondary winding Ns2 in the driver transformer T is also connected to the first terminal OUT+ and the second terminal OUT- of the second sub-load circuit through the first diode D1, when a short circuit occurs, the voltage across the second sub-secondary winding Ns2 will be clamped to the forward conduction voltage Vf of the first diode D1, which is equivalent to a short circuit. At this time, the current flowing through the primary winding Np will increase, thereby increasing the voltage drop through the first resistor R1 and decreasing the voltage across the first capacitor C1.

[0056] When the voltage across the first capacitor C1 is lower than the holding voltage of the driver chip IC, the driver chip IC will stop emitting PWM signals. The first capacitor C1 will be recharged through the first resistor R1. When the voltage across the first capacitor C1 reaches the start-up threshold voltage of the driver chip IC, the driver chip IC will output PWM signals again. However, if the first terminal OUT+ and the second terminal OUT- of the second sub-load circuit are still in a short circuit state, the short circuit protection circuit 20 will repeat the above process to achieve repeated hiccup protection until the short circuit is released and the short circuit protection circuit 20 resumes normal operation.

[0057] Therefore, it can be seen that the short-circuit protection circuit 20 is simple, reliable, and low in cost. Moreover, the power loss generated after short-circuit protection is performed is very low, and normal operation can be restored in a timely manner after the short circuit is cleared.

[0058] This application also provides a power conversion circuit; please refer to [link to relevant documentation]. Figure 3 , Figure 3 This is a schematic diagram of the structure of the first embodiment of the power conversion circuit of this application. In this embodiment, the power conversion circuit 30 includes: a buck-boost circuit 31 and a short-circuit protection circuit 32.

[0059] Specifically, the buck-boost circuit 31 is connected to the short-circuit protection circuit 32 and is used to connect the external second power supply 102 and the load circuit 103. When the buck-boost circuit 31 receives the third power supply provided by the second power supply 102 and the control signal sent by the short-circuit protection circuit 32, it can perform voltage conversion on the third power supply according to the control signal, so as to provide the voltage-converted third power supply to the load circuit 103.

[0060] Optionally, the third power supply provided by the second power supply 102 can specifically correspond to a DC power supply with any reasonable voltage level, and this application does not limit this.

[0061] Specifically, the short-circuit protection circuit 32 can be either the short-circuit protection circuit 10 or the short-circuit protection circuit 20 as described in any of the preceding items. Please refer to the following for details. Figures 1-2 The relevant textual content will not be repeated here.

[0062] Please see Figure 4 , Figure 4 This is a schematic diagram of the second embodiment of the power conversion circuit of this application. This embodiment is based on the first embodiment of the power conversion circuit provided in this application. The buck-boost circuit 41 in the power conversion circuit 40 further includes a second switch Q2, an inductor L, a second diode D2, a third resistor R3, and a second capacitor C2.

[0063] Specifically, the first terminal of the second switch Q2 is connected to the first terminal DC+ of the second power supply, the second terminal of the second switch Q2 is connected to the first terminal of the short-circuit protection circuit 42, the third terminal of the second switch Q2 is connected to the second terminal of the short-circuit protection circuit 42, the first terminal of the inductor L and the second terminal of the second diode D2, the second terminal of the inductor L is connected to the third terminal of the short-circuit protection circuit 42, the first terminal of the second capacitor C2, the first terminal OUT+ of the load circuit, the second terminal of the third resistor R3 and the fourth terminal of the short-circuit protection circuit 42, the first terminal of the second diode D2 is connected to the second terminal OUT- of the load circuit, the first terminal of the second capacitor C2 and the fifth terminal of the short-circuit protection circuit 42, and the second terminal of the third resistor R3 is connected to the second terminal DC- of the second power supply.

[0064] It should be noted that the short-circuit protection circuit 42 further includes a first resistor R1, a first capacitor C1, a driver chip IC, a first switching transistor Q1, a drive transformer T, a primary winding Np, a first secondary winding Ns1, a second secondary winding Ns2, a second resistor R2, and a first diode D1. The correspondence between the first to fifth terminals of the short-circuit protection circuit 42 and each component, as well as their corresponding electrical connections, are as follows: Figure 4 As shown, further details can be found in the references. Figure 2 The relevant textual content will not be elaborated upon here.

[0065] It is understood that the buck-boost circuit 41 can specifically be a non-isolated DC-DC power supply circuit, and after the second power supply provides the third power supply to the non-isolated DC-DC power supply circuit, it can perform voltage conversion on the third power supply through the non-isolated DC-DC power supply circuit and output the voltage conversion to the load circuit.

[0066] The short-circuit protection circuit 42 provides short-circuit protection for the buck-boost circuit 41 and the load circuit. It can also adjust the duty cycle of the control signal output to the buck-boost circuit 41, i.e. the PWM signal, and thus adjust the on and off time ratio of the second switch Q2 to regulate the voltage conversion state of the buck-boost circuit 41, thereby realizing the buck-boost function.

[0067] Unlike existing technologies, the short-circuit protection circuit provided in this application, when receiving a first power supply from the power supply circuit, can determine the transmission method of the control signal based on the first power supply. The output circuit receives the control signal sent by the control circuit and sends the control signal to the load circuit. When a short circuit occurs in the load circuit, the voltage of the first power supply will periodically decrease gradually to below a set voltage threshold, and then gradually increase to above the set voltage threshold. When the voltage of the first power supply is below the set voltage threshold, the control circuit will not send a control signal to the output circuit. When the voltage of the first power supply is above the set voltage threshold, it will then send a control signal to the output circuit. This allows the output to the load circuit to be repeatedly disconnected and then reconnected when a short circuit occurs in the load circuit, enabling the short-circuit protection circuit to work intermittently. This effectively reduces short-circuit losses and lowers the configuration requirements and operating temperature of the components in the short-circuit protection circuit and the load circuit, thus avoiding adverse effects on the lifespan of the components. Furthermore, after the short circuit is cleared, the short-circuit protection circuit can automatically and promptly restore normal power supply to the load circuit, minimizing the impact of the short circuit.

[0068] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A short-circuit protection circuit, characterized in that, The short-circuit protection circuit includes: Power supply circuit; A control circuit is connected to the power supply circuit to receive a first power supply provided by the power supply circuit and to determine the transmission method of the control signal based on the first power supply. An output circuit is connected to the power supply circuit and the control circuit, and is used to connect to an external load circuit. The output circuit receives a control signal sent by the control circuit and sends the control signal to the load circuit so that when a short circuit occurs in the load circuit, the voltage of the first power supply will periodically decrease to below a set voltage threshold and then gradually increase to above the set voltage threshold. Specifically, when the voltage of the first power supply is lower than the set voltage threshold, the control circuit will not send the control signal to the output circuit, and when the voltage of the first power supply is higher than the set voltage threshold, the control signal will be sent to the output circuit.

2. The short-circuit protection circuit according to claim 1, characterized in that, The power supply circuit includes a first resistor and a first capacitor. The first end of the first resistor is used to connect to an external first power supply. The second end of the first resistor is connected to the output circuit, the control circuit, and the first end of the first capacitor. The second end of the first capacitor is connected to the control circuit. The first resistor receives a second power supply provided by the first power supply to store or discharge energy in the second power supply through the first resistor and the first capacitor, so as to convert the second power supply into the first power supply.

3. The short-circuit protection circuit according to claim 2, characterized in that, The resistance of the first resistor is 10Ω-150Ω.

4. The short-circuit protection circuit according to claim 1, characterized in that, The output circuit includes a drive transformer, which includes a primary winding and a secondary winding that are magnetically connected to each other. The first end of the primary winding is connected to the power supply circuit, and the second end of the primary winding is connected to the control circuit. The first and second ends of the secondary winding are respectively used to connect to the first and second ends of the load circuit. The drive transformer receives the control signal sent by the control circuit, converts the control signal, and then sends it to the load circuit.

5. The short-circuit protection circuit according to claim 4, characterized in that, The secondary winding includes a first sub-secondary winding and a second sub-secondary winding. The load circuit includes a first sub-load circuit and a second sub-load circuit. The first end and the second end of the first sub-secondary winding are respectively used to connect to the first end and the second end of the first sub-load circuit. The first end and the second end of the second sub-secondary winding are respectively used to connect to the first end and the second end of the second sub-load circuit. The drive transformer receives the control signal sent by the control circuit, converts the control signal, and sends it to the first sub-load circuit.

6. The short-circuit protection circuit according to claim 5, characterized in that, The output circuit further includes a first diode, the first end of the second sub-secondary winding is connected to the first end of the first diode, the second end of the second sub-secondary winding is connected to the second end of the second sub-load circuit, and the second end of the first diode is connected to the first end of the second sub-load circuit.

7. The short-circuit protection circuit according to claim 5, characterized in that, The output circuit further includes a second resistor, with the first end of the first sub-secondary winding connected to the first end of the second resistor, the second end of the first sub-secondary winding connected to the second end of the first sub-load circuit, and the second end of the second resistor connected to the first end of the first sub-load circuit.

8. The short-circuit protection circuit according to claim 1, characterized in that, The control circuit further includes a driver chip and a first switching transistor. The driver chip is connected to the power supply circuit and the first switching transistor. The first switching transistor is connected to the power supply circuit and the output circuit. The driver chip receives the first power supply provided by the power supply circuit and determines the transmission mode of the control signal according to the first power supply. When it is determined to send the control signal, the driver chip sends the control signal to the first switching transistor so that the first switching transistor can adjust the control signal before sending it to the output circuit.

9. A power conversion circuit, characterized in that, The power conversion circuit includes a step-up / step-down circuit and a short-circuit protection circuit. The step-up / step-down circuit is connected to the short-circuit protection circuit and is used to connect to an external second power supply and a load circuit. The step-up / step-down circuit receives a third power supply provided by the second power supply and a control signal sent by the short-circuit protection circuit, and performs voltage conversion on the third power supply according to the control signal to provide the voltage-converted third power supply to the load circuit. The short-circuit protection circuit is the short-circuit protection circuit as described in any one of claims 1-8.

10. The power conversion circuit according to claim 9, characterized in that, The buck-boost circuit includes a second switching transistor, an inductor, a second diode, a third resistor, and a second capacitor; Wherein, the first terminal of the second switching transistor is connected to the first terminal of the second power supply, the second terminal of the second switching transistor is connected to the first terminal of the short-circuit protection circuit, the third terminal of the second switching transistor is connected to the second terminal of the short-circuit protection circuit, the first terminal of the inductor and the second terminal of the second diode, the second terminal of the inductor is connected to the third terminal of the short-circuit protection circuit, the first terminal of the third resistor, the first terminal of the load circuit and the second terminal of the second capacitor and the fourth terminal of the short-circuit protection circuit, the first terminal of the second diode is connected to the second terminal of the load circuit, the first terminal of the second capacitor and the fifth terminal of the short-circuit protection circuit, and the second terminal of the third resistor is connected to the second terminal of the second power supply.

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