Power circuit protection method, protection circuit and power system

Abstract

The invention provides a power circuit protection method, a protection circuit and a power system, and the method comprises the steps: collecting the temperature and current of a preset position in a power circuit, and obtaining the sampling temperature and sampling current; adjusting the overcurrent protection value of the preset position based on the sampling temperature; comparing the sampling current with an overcurrent protection value at a preset position; and when the sampling current is greater than or equal to the corresponding overcurrent protection value, an overcurrent protection signal is obtained, and the current at the preset position is cut off based on the overcurrent protection signal. According to the invention, the overcurrent protection value is set based on the temperature, and the problems that only a fixed overcurrent protection point is set, so that circuit protection is easily triggered when the design of the overcurrent protection point is low, or protection measures are not taken after circuit overcurrent due to the fact that the design of the overcurrent protection point is high are solved.

Description

Technical Field

[0001] The present invention relates to the field of chip design, and particularly to a power circuit protection method, a protection circuit, and a power system Background Art

[0002] Existing power circuits are often provided with overcurrent protection to solve the problem that the power circuit may be damaged or even destroyed after the circuit exceeds a preset value during use; therefore, current detection is set for the power circuit to ensure that when the power circuit is under a large current and exceeds the preset overcurrent protection value, it can be controlled to turn off, thereby avoiding damage to the power circuit

[0003] However, in the existing overcurrent protection method, in order to be compatible with the entire power circuit, the overcurrent protection point in the power circuit is often preset to a fixed value, ignoring that the change in temperature will affect the value of the overcurrent protection point. When the temperature is high, the overcurrent capacity of the device becomes correspondingly low, so a lower overcurrent protection point is required; when the temperature is low, the overcurrent capacity of the device becomes correspondingly high, so a higher overcurrent protection point is required. Only setting a fixed overcurrent protection point results in that at low temperature, the actual overcurrent capacity of the device is strong, but the device has reached the overcurrent protection point and is turned off; at high temperature, the actual overcurrent capacity of the device is weak, and the device still works when overcurrent protection is required, resulting in the ultimate damage of the device

[0004] Based on this, how to solve the inaccurate overcurrent protection point of the power circuit caused by temperature change has become an urgent problem to be solved

[0005] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solution of the present invention and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of the present invention Summary of the Invention

[0006] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a power circuit protection method, which is used to solve the problems that the existing overcurrent protection method only sets a fixed overcurrent protection point and does not consider the influence of temperature on the overcurrent protection point, resulting in that the overcurrent protection point is designed too low and easily triggers circuit protection, affecting the normal operation of the circuit; or the overcurrent protection point is designed too high, resulting in the circuit not being protected as it should be and causing circuit damage

[0007] To achieve the above purpose and other related purposes, the present invention provides a power circuit protection method, including:

[0008] Collect the temperature and current at a preset position in the power circuit to obtain a sampled temperature and a sampled current

[0009] Adjust the overcurrent protection value at the preset position based on the magnitude of the sampled temperature;

[0010] Compare the sampled current with the overcurrent protection value at the preset position; when the sampled current is greater than or equal to the corresponding overcurrent protection value, obtain an overcurrent protection signal, and cut off the current at the preset position based on the overcurrent protection signal.

[0011] Optionally, the method for setting the overcurrent protection value includes: pre-measuring the maximum value of the operating current at the preset position at different temperatures, and using it as the overcurrent protection value corresponding to the preset position at different temperatures.

[0012] Optionally, the preset position is the position where any power component in the power circuit is located, and the power component is set as the power component with the minimum overcurrent capacity in the power circuit.

[0013] Optionally, the power circuit protection method further includes comparing the sampled temperature with a second preset temperature corresponding to the preset position; when the sampled temperature is greater than or equal to the corresponding second preset temperature, obtain an overtemperature protection signal, and cut off the current at the preset position based on the overtemperature protection signal.

[0014] To achieve the above object and other related objects, the present invention provides a protection circuit for implementing the above power circuit protection method, including: a temperature acquisition module, a threshold adjustment module, a current acquisition module, and an overcurrent protection module;

[0015] The temperature acquisition module is arranged at the preset position of the power circuit to acquire the temperature at the preset position as the sampled temperature;

[0016] The threshold adjustment module is connected to the output end of the temperature acquisition module to regulate the overcurrent protection value at the preset position based on the sampled temperature; adjust the overcurrent protection value at the preset position based on the magnitude of the sampled temperature;

[0017] The current acquisition module is arranged at the preset position to acquire the current at the preset position as the sampled current;

[0018] The overcurrent protection module is connected to the threshold adjustment module and the current acquisition module to compare the sampled current with the overcurrent protection value; when the sampled current is greater than or equal to the corresponding overcurrent protection value, obtain an overcurrent protection signal, and cut off the current at the preset position based on the overcurrent protection signal.

[0019] Optionally, the overcurrent protection module includes a comparator and a protection shutdown unit; a first input end of the comparator is connected to an output end of the threshold adjustment module, a second input end is connected to an output end of the current acquisition module, and an output end is connected to the protection shutdown unit; the protection shutdown unit receives a corresponding overcurrent protection signal and cuts off the current at the preset position based on the overcurrent protection signal.

[0020] Optionally, the protection circuit further includes an overtemperature protection module; the overtemperature protection module is connected to the temperature acquisition module, receives the sampled temperature, and compares the sampled temperature with a second preset temperature corresponding to the preset position; when the sampled temperature is greater than or equal to the corresponding second preset temperature, an overtemperature protection signal is obtained, and the current at the preset position is cut off based on the overtemperature protection signal.

[0021] Optionally, the protection circuit further includes a control module; the control module is connected to the overcurrent protection module and shuts down the power circuit when receiving the overcurrent protection signal.

[0022] To achieve the above object and other related objects, the present invention provides a power system, including a power circuit and M of the above protection circuits; M is an integer greater than or equal to 1;

[0023] The power circuit includes M power components;

[0024] Each protection circuit is correspondingly arranged with each power component; each protection circuit is respectively used to protect the corresponding power component.

[0025] Optionally, the first preset area and the second preset area are adjacently arranged; the power circuit is arranged in the first preset area; each temperature acquisition module is arranged within the first preset area; each overcurrent protection module and each threshold adjustment module are arranged in the second preset area; each current acquisition module is arranged in the first preset area and at a position adjacent to the second preset area; each overcurrent protection module is arranged in the second preset area and at a position adjacent to the first preset area.

[0026] As described above, the power circuit protection method, protection circuit and power system of the present invention have the following beneficial effects:

[0027] 1. The power circuit protection method, protection circuit and power system of the present invention set corresponding overcurrent protection values based on temperature, avoiding the problems in the prior art that only a fixed overcurrent protection point is set, resulting in easy triggering of circuit protection and affecting the normal operation of the circuit when the overcurrent protection point is designed too low; or the overcurrent protection point is designed too high, resulting in easy occurrence of circuit failures and also affecting the normal operation of the circuit.

[0028] 2. The power circuit protection method, protection circuit and power system of the present invention refine the temperature acquisition module and current acquisition module to the power component level and are arranged adjacent to each other, enabling more accurate overcurrent protection and overtemperature protection for power components based on temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It shows a schematic diagram of the steps of the protection method of the present invention.

[0030] Figure 2 It shows a schematic diagram of the framework of the protection circuit of the present invention.

[0031] Figure 3 It shows a schematic diagram of the position of a power system of the present invention.

[0032] Figure 4 It shows a schematic diagram of the position of another power system of the present invention.

[0033] Figure 5 It shows a schematic diagram of the structure of a full-bridge topology.

[0034] Figure 6 It shows a schematic diagram of the structure of a half-bridge topology.

[0035] Figure 7 It shows a schematic diagram of the structure of a single-channel topology.

[0036] DESCRIPTION OF REFERENCE NUMERALS

[0037] 1 Power system

[0038] 101 First preset area

[0039] 101 Second preset area

[0040] 11 Protection circuit

[0041] 111 Temperature acquisition module

[0042] 112 Current acquisition module

[0043] 113 Threshold adjustment module

[0044] 114 Overcurrent protection module

[0045] 115 Overtemperature protection module

[0046] 12 Power circuit

[0047] 121 Power component

[0048] 121a Full-bridge topology

[0049] 121b Half-bridge topology

[0050] 121c single-channel topology Specific implementation manners

[0051] The following uses specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0052] Please refer to Figures 1 to 7 It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0053] Generally, the protection of power circuits is divided into two categories. The first category is overcurrent protection, and the second category is overtemperature protection.

[0054] Overcurrent protection is a protection measure for power circuits. When the circuit is applied, it protects against current states that may occur, including short-circuit states, to avoid excessive current from damaging or even destroying the power components in the power circuit. When an over-threshold current state appears, by sampling electrical parameters such as the current of the power components and through a certain control logic, the power components are timely turned off, thereby achieving the protection of the power components.

[0055] Overtemperature protection is another protection measure. By detecting the temperature of the power circuit, the temperature of the control circuit is controlled not to exceed the junction temperature. Generally, it prevents the working temperature of a certain power component in the circuit from being too high due to improper control of the signal magnitude, or the circuit temperature from being abnormally high due to a high ambient temperature.

[0056] In practical applications, power circuits with power components will select overcurrent protection according to conditions such as design and process parameters, and usually select a relatively fixed overcurrent protection point. However, the fixed overcurrent protection point itself is not very reasonable. Taking the circuit wiring layer as an example, the circuit wiring layer generally uses aluminum or copper as the main material, and the overcurrent capabilities of both show a correlation with temperature: at lower temperatures, the overcurrent capability is stronger; at higher temperatures, the overcurrent capability is weaker. Especially when the temperature is higher, the overcurrent capability drops significantly. In this case, it is more reasonable for the overcurrent protection point to be correspondingly reduced. And there is also a corresponding situation in power components, that is, temperature affects the overcurrent capability of power components.

[0057] However, since the overcurrent capacity of the power device corresponding to the temperature change is not taken into account in the process of setting the overcurrent protection current, only the temperature is collected for junction temperature protection, and the overtemperature capacity of the power device at different temperatures is not better utilized. The temperature of the power component collected is not matched with the overcurrent protection function, that is, the reasonable change of the overcurrent protection point is not controlled at different temperatures. As a result, the overcurrent protection function is not accurate, the fixed value limits the accuracy of the overcurrent protection function, and cannot respond to temperature changes. At the same time, it only protects the power component as a whole, and does not provide targeted protection for the local weaknesses of the power component. Either the overcurrent protection point is too high, and the overcurrent capacity of the power component drops significantly when the temperature is high, or the local overcurrent capacity of the power component is insufficient; or because the overcurrent protection point is too low, it is easy to trigger the undesirable protection, the power circuit is prone to failure, affecting the normal operation of the circuit, and the true performance of the circuit cannot be exerted.

[0058] In other words, setting a fixed overcurrent protection point will either limit the ultimate performance of the circuit, causing the circuit to easily trigger protection; or the protection will not be in place, causing the power circuit to fail easily at high temperatures or a certain proportion of the circuit due to insufficient local overcurrent capacity.

[0059] Based on this, the present invention provides a power circuit protection method, a protection structure and a power system to solve the problem that the overcurrent protection method only sets a fixed overcurrent protection point, and does not take into account the influence of temperature on the overcurrent protection point, resulting in the overcurrent protection point being designed too low and easily triggering circuit protection, affecting the normal operation of the circuit; or the overcurrent protection point being designed too high and causing the circuit to easily fail, which also affects the normal operation of the circuit.

[0060] Embodiment 1

[0061] like Figure 1 As shown, this embodiment provides a power circuit protection method, including:

[0062] S1. Collecting the temperature and current at a preset position in the power circuit to obtain a sampled temperature and a sampled current.

[0063] Specifically, the preset position is the position of any power component in the power circuit. In this embodiment, if there are M power components 121 in the power circuit, the preset position is set to the position of any power component 121 among the M power components 121, thereby protecting the selected power device. In fact, in another embodiment, the preset position can also be set to the position of a wire or other device (such as a resistor or inductor) in the power circuit, thereby protecting the power circuit.

[0064] As an example, the power component is set as the power component with the minimum overcurrent capacity in the power circuit. At least one of the M power components 121 is the power component 121 with the minimum overcurrent capacity in the power circuit 12, so as to ensure that the power component 121 with the minimum overcurrent capacity will not be damaged due to excessive current, and then other power components 121 with relatively greater overcurrent capacity will not be damaged either.

[0065] Specifically, a thermal distribution map of the power circuit 12 is obtained through device simulation, and then, based on the position where the heat distribution is most concentrated, the power component 121 with the minimum overcurrent capacity in the power circuit 12 is determined. The overcurrent capacity is the bearing capacity of the power component 121 at the maximum rated current, and generally can be set based on materials, line widths, etc. In actual use, the overcurrent capacity of each power component 121 can be detected through the simulation process to determine the power component 121 with the minimum overcurrent capacity in the power circuit 12.

[0066] In one example, the power component 121 with the minimum overcurrent capacity can be determined by calculating the heat distribution, such as: A11. Determine the design process of the power circuit 12 and perform a pre-layout design of the layout. At this time, the temperature acquisition module 111 is not set in the layout; A12. Extract the parasitic parameters of the pre-layout layout. The extracted parameters include resistance, capacitance, and inductance, so as to generate a new circuit netlist; A13. Perform a post-simulation using the circuit netlist with the extracted parasitic parameters to obtain the current simulation distribution of the devices at each position in the layout under the normal working state, and calculate the heat distribution based on the calculation; A14. The hottest point in the heat distribution is the position with weak overcurrent capacity, and then the temperature acquisition module 111 is set at this position to complete the secondary layout design.

[0067] In another example, the power component 121 with the minimum overcurrent capacity can be determined by verification, such as: A21. According to the wiring characteristics of the layout of the power circuit 12, a position with weak overcurrent capacity is preset, and the temperature acquisition module 111 is set at this position; A22. Extract the parasitic parameters of the layout. The extracted parameters include resistance, capacitance, and inductance, so as to generate a new circuit netlist; A23. Perform a post-simulation using the circuit netlist with the extracted parasitic parameters to obtain the current simulation distribution of the devices at each position in the layout under the normal working state, calculate the heat distribution based on the calculation, and verify whether the temperature acquisition module 111 is placed at the hottest point; A24. If it is not the hottest point position, then adjust the position and re-simulate and verify until the power component 121 with the minimum overcurrent capacity is confirmed.

[0068] It should be noted that the power component 121 with the minimum overcurrent capacity can also be determined based on the process experience of manufacturing the power circuit 12, thereby protecting the power circuit 12, and this is not limited to this embodiment. For example, by observing the line width of each power component 121 and judging the resistance of each power component 121, the power component 121 with the minimum overcurrent capacity can be determined.

[0069] Specifically, the power component 121 is set as a power element or a power module including a plurality of power elements. In this embodiment, the power circuit 12 includes a plurality of power components 121; and the power component 121 is composed of a plurality of power elements or a plurality of power modules. The power element in this embodiment refers to the basic component in the power circuit 12, including but not limited to components such as MOS transistors; the power module in this embodiment is a structure formed by connecting power elements to form a structure with a specific function, such as: single-channel topology structure, half-bridge topology structure, full-bridge topology structure, three-phase topology structure (such as Figures 5 to 7 shown).

[0070] As a first example, as Figure 5 shown, the full-bridge topology structure 121a includes a first power transistor Q1, a second power transistor Q2, a third power transistor Q3, and a fourth power transistor Q4; wherein, the control terminals of the first power transistor Q1, the second power transistor Q2, the third power transistor Q3, and the fourth power transistor Q4 are all connected to a control signal; the first end of the first power transistor Q1 is connected to the first end of the second power transistor Q2; the second end of the first power transistor Q1 is connected to the first end of the fourth power transistor Q4; the second end of the second power transistor Q2 is connected to the first end of the third power transistor Q3; the second end of the third power transistor Q3 is connected to the second end of the fourth power transistor Q4; the first end of the first power transistor Q1 is connected to a first input voltage, and the second end outputs a first output voltage; the second end of the second power transistor Q2 outputs a second output voltage. The second end of the fourth power transistor Q2 is grounded. The full-bridge topology structure 121a is a power module including 4 power elements, and any one of the 4 power elements in the full-bridge topology structure 121a can be protected respectively based on the power circuit protection method provided in this embodiment, or the full-bridge topology structure 121a as a whole can be protected based on the power circuit protection method provided in this embodiment.

[0071] As a second example, as Figure 6The half-bridge topology 121b shown includes a fifth power transistor Q5 and a sixth power transistor Q6. Among them, the control terminals of the fifth power transistor Q5 and the sixth power transistor Q6 are both connected to a control signal. The first end of the fifth power transistor Q5 is connected to a second input voltage, and the second end outputs a third output voltage. The first end of the sixth power transistor Q6 is connected to the second end of the fifth power transistor Q5, and the second end is grounded. The half-bridge topology 121b is a power component including 2 power elements, and any one of the 2 power elements in the half-bridge topology 121b can be protected respectively based on the power circuit protection method provided in this embodiment, or the entire half-bridge topology 121b can be protected based on the power circuit protection method provided in this embodiment.

[0072] As a third example, as Figure 7 The single-channel topology 121c shown includes a seventh power transistor Q7. Among them, the control terminal of the seventh power transistor Q7 is connected to a control signal. The first end of the seventh power transistor Q7 is connected to a third input voltage, and the second end outputs a fourth output voltage. The single-channel topology 121c is a power component including 1 power element, and the single-channel topology 121c can be directly protected respectively based on the power circuit protection method provided in this embodiment.

[0073] In addition, the power component in this embodiment can also be set as a three-phase topology. Among them, the three-phase topology can be set as three parallel half-bridge structures.

[0074] In this embodiment, the power circuit protection method set in this embodiment can be applied both to the power element level to protect the power element, and to the power component level to protect the entire power component. The difference between the two is that the detection and protection of power elements are more accurate than those of power components. However, the detection and protection of power components save a part of the cost, reduce the number of multiple temperature acquisition modules and current acquisition modules, and also reduce the wiring.

[0075] S2. Adjust the overcurrent protection value at the preset position based on the magnitude of the sampled temperature.

[0076] Specifically, the method for setting the overcurrent protection value includes: pre-measuring the maximum value of the operating current at the preset position at different temperatures, and using it as the overcurrent protection value corresponding to the preset position at different temperatures. For example, pre-measure the maximum value of the operating current at the preset position (in this embodiment, the power component 121) at 100 °C, and use it as the overcurrent protection value of the preset position (power component 121) at 100 °C, which is subsequently used to protect the normal operation of the power circuit.

[0077] As an example, in this embodiment, when the sampled temperature is lower than the first preset temperature, the overcurrent protection value at the preset position is set to a high threshold; when the sampled temperature is greater than or equal to the first preset temperature, the overcurrent protection value at the preset position is set to a low threshold. The overcurrent capacity of the power component 121 shows a correlation with temperature: generally speaking, when the temperature is lower, the overcurrent capacity is stronger; when the temperature is higher, the overcurrent capacity is weaker. In this embodiment, the first preset temperature is used as the distinction for setting the high or low overcurrent capacity of the power component 121. When the temperature is higher, the overcurrent protection value is set lower, and when the temperature is lower, the overcurrent protection value is set higher.

[0078] It should be noted that the overcurrent capacity of the power component 121 showing a correlation with temperature does not mean that when the temperature of the power component 121 increases, the overcurrent protection value will necessarily decrease; in another embodiment, as the temperature of the power component 121 increases, the overcurrent protection value remains unchanged or even increases. Therefore, it is necessary to set the overcurrent protection value of the power component 121 based on the actual situation.

[0079] It should be further noted that when pre-determining the overcurrent protection value, the overcurrent protection value of the power component 121 can also be adjusted based on actual needs; for example, in order to improve the protection strength of the power circuit, the overcurrent protection value of the power component 121 is adjusted to be less than the maximum value of the operating current at the corresponding temperature.

[0080] S3. Compare the sampled current with the overcurrent protection value at the preset position; when the sampled current is greater than or equal to the corresponding overcurrent protection value, an overcurrent protection signal is obtained, and based on the overcurrent protection signal, the current at the preset position is cut off.

[0081] Specifically, the maximum current (overcurrent protection value) that the power component 121 can operate at is determined by temperature, and then it is determined whether the sampled current of the power component 121 at this temperature exceeds the overcurrent protection value. If it exceeds the overcurrent protection value, corresponding protection measures are taken to protect the power component 121. For example, in this embodiment, the power component 121 with a current exceeding the overcurrent protection value is turned off (i.e., the current at the preset position is cut off), thereby ensuring the safety of the power circuit 12 to the greatest extent; in another embodiment, the current in the power component 121 can also be reduced to avoid overcurrent, but compared with the direct turn-off in this embodiment, the reliability will be correspondingly reduced. In fact, the method of protecting the power component 121 is not limited to this embodiment, and any setting that can protect the power component 121 based on the overcurrent protection signal falls within the protection scope of this embodiment.

[0082] S31. The power circuit protection method further includes comparing the sampled temperature with a second preset temperature corresponding to the preset position; when the sampled temperature is greater than or equal to the corresponding second preset temperature, an over-temperature protection signal is obtained, and based on the over-temperature protection signal, the current at the preset position is cut off.

[0083] Specifically, since the power component 121 itself also has a corresponding working tolerance temperature, that is, the over-temperature protection temperature, when protecting the power component 121 in the power circuit 12, it is necessary to consider both the influence of temperature on the over-current capacity of the power component 121 and the fact that temperature itself is also a limiting factor when the power component 121 is working. Based on this, on the basis of over-current protection for the power component 121, over-temperature protection for the power component 121 also needs to be considered. Among them, the temperature set for over-temperature protection is highly correlated with the material properties of the power component 121 itself and is often set as a fixed value. Therefore, the first preset temperature and the second preset temperature are set separately, and their values can be equal or unequal in actual use.

[0084] In this embodiment, the power component 121 is set to work in a small current state, the circuit temperature is low, and the limit over-current capacity of the power component 121 is high. By adopting a relatively high over-current protection point, mis-triggering of over-current protection can be avoided; when the power component 121 works in a large current state, the circuit temperature is high, and the limit over-current capacity of the power component 121 decreases. At this time, it switches to a low over-current protection point. When an over-current situation occurs, the power circuit 12 is better protected, improving the reliability of the power circuit operation.

[0085] As Figures 2 to 4 shown, this embodiment also provides a protection circuit 11 for implementing the above power circuit protection method. The protection circuit includes: a temperature acquisition module 111, a threshold adjustment module 112, a current acquisition module 113, and an over-current protection module 114;

[0086] As Figures 2 to 4 shown, the temperature acquisition module is arranged at the preset position of the power circuit to acquire the temperature at the preset position as the sampled temperature.

[0087] Specifically, as an example, the preset position is the position where any power component in the power circuit is located; the temperature acquisition module is arranged at the position where any power component is located. In fact, the preset position can be set at any position of the power circuit, and the specific setting has been described previously, so it will not be elaborated here one by one.

[0088] As an example, the power component is set as the power component with the minimum over-current capacity in the power circuit to ensure the normal operation of the power circuit. In this embodiment, the power component 121 is set as a power element or a power component including a plurality of power elements. In this embodiment, taking the power element as an example, the normal use of the corresponding power element is protected by detecting the temperature and current of the power element. In addition, in another embodiment, the power component can be used as the acquisition object to protect the normal use of the power component.

[0089] Specifically, the temperature acquisition module 111 is set as a temperature sensing device; the temperature sensing device converts the thermal signal of the corresponding power component 121 into an electrical signal and transmits it to the corresponding threshold adjustment module 113.

[0090] As an example, as Figure 2 shown in the example of the protection circuit 11. The temperature acquisition module 111 is set as a polycrystalline resistor, which has a positive or negative temperature coefficient. When the temperature changes, the resistance value also changes, that is, the resistance value can quickly respond and follow the temperature change, and then convert the thermal signal into a corresponding electrical signal (voltage signal) for comparison by a subsequent comparator. In this embodiment, there are two polycrystalline resistors in the temperature acquisition module 111, and the temperature coefficients of the two are different. The temperature change situation can be obtained by comparing the resistance changes of the polycrystalline resistors. It should be noted that the temperature sensing device can also be set as other components, and is not limited to this embodiment.

[0091] As Figures 2 to 4 shown, the threshold adjustment module 113 is connected to the output end of the temperature acquisition module 111, and regulates the over-current protection value at the preset position based on the sampled temperature; adjusts the over-current protection value at the preset position based on the magnitude of the sampled temperature. Its specific setting method has been described above and will not be elaborated here.

[0092] As an example, the threshold adjustment module includes a logic unit and a threshold setting unit; the logic unit includes a logic judgment component and a plurality of threshold comparators; the values of the sampled temperature are compared by the multi-level threshold comparators to facilitate setting the over-current protection value. In this embodiment, three preset temperature ranges can be set through two-level threshold comparators; it is set that the first input terminal of the first-level threshold comparator is connected to the voltage obtained by converting the sampled temperature, and the second input terminal is connected to the first preset voltage to obtain a first output result; it is set that the first input terminal of the second-level threshold comparator is connected to the voltage obtained by converting the sampled temperature, and the second input terminal is connected to the second preset voltage to obtain a second output result; wherein, the second preset voltage is greater than the first preset voltage; if the voltage obtained by converting the sampled temperature is less than the first preset voltage, it is determined that the sampled temperature is within the first preset temperature range; if the voltage obtained by converting the sampled temperature is greater than the first preset voltage and less than the second preset voltage, it is determined that the sampled temperature is within the second preset temperature range; if the voltage obtained by converting the sampled temperature is greater than the second preset voltage, it is determined that the sampled temperature is within the third preset temperature range; the logic judgment component determines the level states of the first output result and the second output result output, and further obtains the temperature range at this time, and then outputs the result of the logic judgment; the threshold setting unit receives the output signal of the logic unit and adjusts the size of the threshold setting based on the determination result of the logic unit, that is: the over-current protection point of each over-current protection module 114.

[0093] In this embodiment, when each sampled temperature is lower than the first preset temperature, the over-current protection value of the corresponding power component is the high threshold; when each sampled temperature is greater than or equal to the first preset temperature, the over-current protection value of the corresponding power component is the low threshold. During actual use, based on the comparison relationship between the sampled temperature and the first preset temperature, the corresponding over-current protection value can be set as the reference current (or reference voltage) for subsequent judgment of whether the current is over-current.

[0094] It should be noted that the actual setting method of each threshold adjustment module 113 is not limited to this embodiment, and any setting that can select the corresponding threshold size based on temperature is within the protection scope of this embodiment; during actual use, the threshold size of the over-current protection value can be adjusted based on a certain temperature range or a specific temperature, which is not limited to this embodiment.

[0095] As Figures 2 to 4 shown, the current acquisition module 112 is arranged at the preset position and acquires the current at the preset position as the sampled current.

[0096] Specifically, the current acquisition module 112 is set as a sampling tube; the sampling tube acquires the current signal at the corresponding preset position (in this embodiment, the position where the power component 121 is located) and outputs it to the corresponding over-current protection module 114.

[0097] As an example, the sampling tube is set as a MOS transistor, and the current signal of the corresponding power component 121 is mirror-collected by setting the current mirror configuration. In this example, the mirror factor of the current mirror is set to 1:1 to ensure more accurate sampling current; in another example, the mirror factor of the current mirror has a certain ratio, and the sampled current signal is scaled down proportionally and then output to the comparator for subsequent comparison and judgment with the reference current (i.e., the overcurrent protection value).

[0098] As Figures 2 to 4 As shown, the overcurrent protection module 114 is connected to the threshold adjustment module 113 and the current acquisition module 112, and compares the sampled current with the overcurrent protection value; when the sampled current is greater than or equal to the corresponding overcurrent protection value, an overcurrent protection signal is obtained, and based on the overcurrent protection signal, the current at the preset position is cut off.

[0099] As an example, the overcurrent protection module 114 includes a comparator and a protection shutdown unit; the first input terminal of the comparator is connected to the output terminal of the corresponding threshold adjustment module 113 (connected to the output terminal of the threshold setting unit in this embodiment), the second input terminal is connected to the output terminal of the corresponding current acquisition module, and the output terminal is connected to the corresponding protection shutdown unit; the protection shutdown unit is connected to the control terminal of the corresponding power component 121, receives the corresponding overcurrent protection signal, and shuts down the corresponding power component 121 based on the overcurrent protection signal.

[0100] This embodiment ensures that when the temperature is relatively high, the overcurrent protection value is relatively low, and the overcurrent protection module 114 will trigger overcurrent protection when detecting that the sampled current reaches the lower overcurrent protection value; while when the temperature is relatively low, the overcurrent protection value is relatively high, and the overcurrent protection module 114 will trigger overcurrent protection when detecting that the sampled current reaches the higher overcurrent protection value. The overcurrent protection module 114 shuts down the corresponding power component 121 to ensure that the power component 121 is not damaged.

[0101] As Figures 2 to 4 As shown, the protection circuit 11 further includes the overtemperature protection module 115; the overtemperature protection module 115 is connected to the temperature acquisition module 111, receives the sampled temperature, and compares the sampled temperature with the second preset temperature corresponding to the preset position; when the sampled temperature is greater than or equal to the corresponding second preset temperature, an overtemperature protection signal is obtained, and based on the overtemperature protection signal, the current at the preset position is cut off.

[0102] Specifically, the over-temperature protection module 115 in this embodiment includes a temperature comparator and a protection shutdown unit. The first input terminal and the second input terminal of the temperature comparator are respectively connected to two polycrystalline resistors with opposite temperature characteristics (one polycrystalline resistor has a linearly decreasing resistance with increasing temperature; one polycrystalline resistor has a linearly increasing resistance with decreasing temperature), and the output terminal outputs a temperature comparison result. Due to the opposite changes in temperature characteristics, when the temperature changes at the first input terminal and the second input terminal of the temperature comparator exceed a certain range, the output result of the comparator will flip, that is, when the second preset temperature (the highest junction temperature) is exceeded, corresponding over-temperature protection measures need to be taken for the power component 121, such as turning off the power component 121.

[0103] It should be noted that, in this embodiment, when the power circuit 12 is locally heated in a certain current state, the power circuit 12 can be protected based on the over-temperature protection module 115, and then the power circuit is directly turned off to protect the power circuit. Compared with only taking the over-current protection method, taking both over-temperature protection and over-current protection can protect the power circuit 12 more effectively, reliably and quickly.

[0104] Specifically, the protection circuit 11 further includes a control module (not shown in the figure); the control module is respectively connected to the over-temperature protection module 115 and the over-current protection module 114, and turns off the power circuit when receiving any one of the over-temperature protection signal and the over-current protection signal.

[0105] It should be noted that the control module can be set as a controller outside the power circuit 12. When the controller receives the over-current protection signal or the over-temperature protection signal, it can directly turn off the entire power circuit 12.

[0106] It should be further noted that the corresponding power component 121 is directly turned off through the over-temperature protection module 115 and the over-current protection module 114, so that the power circuit 12 does not work; and through the control module, the entire power circuit 12 can be directly turned off (equivalent to turning off all power components 121). Both shutdown methods achieve over-temperature protection and over-current protection for the power circuit 12.

[0107] Embodiment 2

[0108] This embodiment provides a power system 1, including a power circuit 12 and M protection circuits 11 provided in Embodiment 1.

[0109] Specifically, the power circuit 12 includes M power devices 121.

[0110] Specifically, each protection circuit is provided corresponding to each power component one by one, and each protection circuit is respectively used to protect the corresponding power component.

[0111] As shown in Figure 3 FIG. 1, in the first example, the first preset area 101 and the second preset area 102 are adjacent to each other; the power circuit 12 is disposed in the first preset area 101; each temperature acquisition module 111 is disposed within the first preset area 101; each overcurrent protection module 114 and threshold adjustment module 113 are disposed in the second preset area 102; each current acquisition module 112 is disposed in the first preset area 101 and adjacent to the second preset area 102; each overcurrent protection module 114 is disposed within the second preset area 102 and adjacent to the first preset area 101.

[0112] Further, when each protection circuit further includes an overtemperature protection module 115, each overtemperature protection module 115 is disposed within the second preset area 102.

[0113] In this example, the power system 1 includes a power circuit 12 and M protection circuits 11. In actual layout setting, each temperature acquisition module 111 and each current acquisition module 112 can be disposed at the positions of the corresponding power components 121, and the transmitted results are output to the overcurrent protection module 114 and overtemperature protection module 115 in the second preset area 102 through leads, and then the corresponding power elements are turned off through the output results of the overcurrent protection module 114 and overtemperature protection module 115 respectively. Among them, since more accurate transmission is required between the current acquisition module 112 and the overcurrent protection module 114, the current acquisition module 112 and the overcurrent protection module 114 are disposed nearby when they are set. Therefore, each current acquisition module 112 is disposed in the first preset area 101 and adjacent to the second preset area 102; each overcurrent protection module 114 is disposed within the second preset area 102 and adjacent to the first preset area 101.

[0114] As shown in Figure 4 FIG. 2, the first preset area 101 and the second preset area 102 are adjacent to each other; the power circuit 12, each current acquisition module 112, each overcurrent protection module 114, threshold adjustment module 113, and each temperature acquisition module 111 are all disposed within the first preset area 101, and each current acquisition module 112, each overcurrent protection module 114, threshold adjustment module 113, and each temperature acquisition module 111 are all disposed around the corresponding power component 121.

[0115] Further, when each protection circuit further includes an overtemperature protection module 115, each overtemperature protection module 115 is disposed within the second preset area 102.

[0116] This example is basically the same as the first example, except that each current acquisition module 112, each overcurrent protection module 114, and each temperature acquisition module 111 are all arranged within the first preset area 101. Compared with the first example, in this example, the current acquisition module detects the local part of the power component 121, that is, the magnitude of the current measured by the current acquisition module 112 reflects the local position of the power component 121, so that the magnitude of the current of the power component 121 at the local weak position can be measured more accurately. At the same time, in this example, the temperature detection of the local position can be more accurate, and finally the overcurrent protection point of the power element can be dynamically controlled within a more ideal range of change.

[0117] In summary, the present invention provides a power circuit protection method, a protection circuit, and a power system, including: collecting the temperature and current at a preset position in the power circuit to obtain a sampled temperature and a sampled current; adjusting the overcurrent protection value at the preset position based on the magnitude of the sampled temperature; comparing the sampled current with the overcurrent protection value at the preset position; when the sampled current is greater than or equal to the corresponding overcurrent protection value, obtaining an overcurrent protection signal, and cutting off the current at the preset position based on the overcurrent protection signal. The present invention sets the overcurrent protection value based on the temperature, avoiding problems such as easily triggering circuit protection when the overcurrent protection point is designed too low or no protection measures are taken after the circuit is overcurrent when only a fixed overcurrent protection point is set. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0118] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A power circuit protection method, characterized in that, The power circuit protection method includes: Collect the temperature and current at a preset position in the power circuit to obtain a sampled temperature and a sampled current; Adjust the overcurrent protection value at the preset position based on the magnitude of the sampled temperature; Compare the sampled current with the overcurrent protection value at the preset position; when the sampled current is greater than or equal to the corresponding overcurrent protection value, obtain an overcurrent protection signal, and cut off the current at the preset position based on the overcurrent protection signal.

2. The power circuit protection method according to claim 1, wherein: The method for setting the overcurrent protection value includes: pre-measuring the maximum value of the operating current at the preset position at different temperatures, and using it as the overcurrent protection value corresponding to the preset position at different temperatures.

3. The power circuit protection method according to claim 1, wherein: The preset position is the position where any power component in the power circuit is located, and the power component is set as the power component with the minimum overcurrent capacity in the power circuit.

4. The power circuit protection method according to claims 1 to 3, characterized in that: The power circuit protection method further includes comparing the sampled temperature with a second preset temperature corresponding to the preset position; when the sampled temperature is greater than or equal to the corresponding second preset temperature, obtain an overtemperature protection signal, and cut off the current at the preset position based on the overtemperature protection signal.

5. A protection circuit for implementing the power circuit protection method according to any one of claims 1 to 4, characterized in that, The protection circuit includes: a temperature acquisition module, a threshold adjustment module, a current acquisition module, and an overcurrent protection module; The temperature acquisition module is disposed at the preset position of the power circuit to collect the temperature at the preset position as the sampled temperature; The threshold adjustment module is connected to the output end of the temperature acquisition module to regulate the overcurrent protection value at the preset position based on the sampled temperature; adjust the overcurrent protection value at the preset position based on the magnitude of the sampled temperature; The current acquisition module is disposed at the preset position to collect the current at the preset position as the sampled current; The overcurrent protection module is connected to the threshold adjustment module and the current acquisition module to compare the sampled current with the overcurrent protection value; when the sampled current is greater than or equal to the corresponding overcurrent protection value, obtain an overcurrent protection signal, and cut off the current at the preset position based on the overcurrent protection signal.

6. The protection circuit according to claim 5, characterized in that: The overcurrent protection module includes a comparator and a protection shutdown unit; the first input end of the comparator is connected to the output end of the threshold adjustment module, the second input end is connected to the output end of the current acquisition module, and the output end is connected to the protection shutdown unit; The protection shutdown unit receives the corresponding overcurrent protection signal and cuts off the current at the preset position based on the overcurrent protection signal.

7. The protection circuit according to claim 5, wherein: The protection circuit further includes an overtemperature protection module; the overtemperature protection module is connected to the temperature acquisition module, receives the sampled temperature, and compares the sampled temperature with a second preset temperature corresponding to the preset position; when the sampled temperature is greater than or equal to the corresponding second preset temperature, obtain an overtemperature protection signal, and cut off the current at the preset position based on the overtemperature protection signal.

8. The protection circuit according to claim 5, wherein: The protection circuit further includes a control module; the control module is connected to the overcurrent protection module and shuts down the power circuit when receiving the overcurrent protection signal.

9. A power system, characterized in that: The power system includes a power circuit and M protection circuits as described in any one of claims 5 to 8; M is an integer greater than or equal to 1; The power circuit includes M power components; Each protection circuit is arranged in one-to-one correspondence with each power component; each protection circuit is respectively used to protect the corresponding power component.

10. The power system according to claim 9, wherein: The first preset area and the second preset area are adjacent to each other; the power circuit is arranged in the first preset area; Each temperature acquisition module is arranged within the first preset area; Each overcurrent protection module and each threshold adjustment module are arranged in the second preset area; Each current acquisition module is arranged in the first preset area and at a position adjacent to the second preset area; Each overcurrent protection module is arranged within the second preset area and at a position adjacent to the first preset area.

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