An overcurrent protection device, method and vehicle

Abstract

The application discloses an overcurrent protection device, method and vehicle, the device comprising a first sampling resistor, an amplification module, a comparison module and a control module, the first input end of the input power supply and the amplification module is connected with the first end of the first sampling resistor, the second end of the first sampling resistor is connected with the first end of each load and the second input end of the amplification module respectively, the first sampling resistor is used for inputting the first voltage obtained by dividing the input power supply into each load; the amplification module is used for amplifying the voltage input to the first input end of the comparison module; the comparison module is used for outputting the second voltage in the case that the amplified voltage is greater than the reference reference voltage; the control module is used for outputting the third voltage to each load under the control of the second voltage, so that each load is closed under the action of the first voltage and the third voltage. The above-mentioned device is simple to build, low in cost, can reliably realize overcurrent protection, can be mass-produced, and solves the problem of insufficient chip production capacity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit, in particular to an overcurrent protection device, method and vehicle. BACKGROUND

[0002] At present, automobile manufacturers realize continuous high-side driving scheme by installing pre-driving chips in each load driving circuit, wherein the load driving circuit realizes internal overcurrent protection through the pre-driving chip, and the chip is also integrated with functions such as over-temperature protection and low-voltage shutdown, which is of great significance to vehicle load driving. However, the manufacturing of such chips is monopolized, the production capacity is limited, and the price is high, which cannot meet the current large production demand. SUMMARY

[0003] The embodiments of the present application provide an overcurrent protection device, method and vehicle, which realizes the function of overcurrent protection by controlling the closing of the load driving circuit when the sampled current is greater than the overcurrent value, and the overcurrent protection device is simple to build, low in cost, and can be mass-produced, solving the problem of insufficient production capacity of pre-driving chips.

[0004] In a first aspect, the present application provides an overcurrent protection device, which comprises a first sampling resistor, an amplification module, a comparison module and a control module, an input power supply is connected with a first end of the first sampling resistor, a second end of the first sampling resistor is connected with a first end of each load in at least one load, a first input end of the amplification module is connected with the first end of the first sampling resistor, and a second input end of the amplification module is connected with the second end of the first sampling resistor; the first sampling resistor is used to input a first voltage obtained by dividing the voltage of the input power supply to the first end of each load; the amplification module is used to input an amplified voltage obtained by amplifying the input voltage to a first input end of the comparison module; the comparison module is used to output a second voltage when it is determined that the amplified voltage is greater than a reference reference voltage of a second input end of the comparison module; and the control module is used to output a third voltage to a second end of each load under the control of the second voltage, so as to close each load under the action of the first voltage and the third voltage.

[0005] In summary, the overcurrent protection device provided by the present application controls the voltage across the load by combining simple elements, thereby controlling the opening and closing of the load and realizing the function of overcurrent protection. Moreover, the overcurrent protection device is simple to build with simple elements, low in cost, and can be mass-produced, which can solve the problem of insufficient production capacity of pre-driving chips.

[0006] In a possible implementation, the overcurrent protection device further comprises a controller, the controller comprising a first pin connected to the output of the amplification module; the controller being configured to control the opening or closing of one or more loads according to the current sampled at the output of the amplification module by the first pin. In addition to controlling the voltage across the load by the circuit elements and controlling the closing of the load to achieve overcurrent protection, the application can also achieve overcurrent protection by the controller. The controller controls the opening or closing of the load according to the current sampled from the circuit, which can provide multiple protection and detection for overcurrent conditions.

[0007] In a possible implementation, the controller further comprises a plurality of second pins, one of the plurality of second pins being connected to one of the plurality of loads; and the controller is specifically configured to output a low-level signal from one or more second pins when the current sampled by the first pin is greater than a first threshold value, the first threshold value being determined according to a reference reference voltage, the amplification module, and the first sampling resistor. The controller is connected to the load through the second pin and controls the closing of the load through the output low-level signal, which can provide multiple protection for the load in the overcurrent condition.

[0008] In a possible implementation, the control module comprises a first resistor, a first sub-module, a second sub-module, and a third sub-module, the first sub-module comprising a second resistor and a first transistor, the second sub-module comprising a third resistor, a fourth resistor, and a second transistor, and the third sub-module comprising a fifth resistor, a sixth resistor, and a first field effect transistor; a first end of the first resistor being connected to the output of the comparison module, and a second end of the first resistor being connected to the second resistor and the base of the first transistor; a second end of the third resistor being connected to the collector of the first transistor, and the fourth resistor and the emitter of the second transistor being connected to the first detection voltage; the fifth resistor being connected to the collector of the second transistor, and the drain of the first field effect transistor being connected to the second end of each load; the first sub-module being configured to be turned on under the action of the second voltage output by the comparison module; the second sub-module and the third sub-module being configured to be turned on under the action of the first detection voltage when the first sub-module is turned on, so that the drain of the first field effect transistor outputs the third voltage to the second end of each load. In the above process, the control module determines the third voltage output to the load by combining the simple elements and the second voltage output by the comparison module, thereby controlling the closing of the load and achieving overcurrent protection.

[0009] In a possible implementation, the control module has the following specific connection relationship: the second end of the second resistor is connected to the emitter of the first transistor, the emitter of the first transistor is grounded, the collector of the first transistor is connected to the second end of the third resistor, the first end of the third resistor is connected to the base of the second transistor, the second end of the fourth resistor is connected to the base of the second transistor, the first end of the fourth resistor is connected to the emitter of the second transistor, the second end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is grounded, the second end of the sixth resistor is connected to the source of the first field effect transistor, and the gate of the first field effect transistor is connected to the first end of the sixth resistor.

[0010] In a possible implementation, the overcurrent protection device further comprises a reference voltage determination module, the first end of the reference voltage determination module is connected to the second detection voltage, and the second end of the reference voltage determination module is connected to the second input end of the comparison module. The reference voltage determination module is configured to convert the second detection voltage into a reference voltage and input the reference voltage into the second input end of the comparison module.

[0011] In a possible implementation, the reference voltage determination module comprises a second sampling resistor, a third sampling resistor and a first capacitor, the first end of the second sampling resistor is connected to the second detection voltage, the second end of the second sampling resistor is connected to the second end of the third sampling resistor, the first end of the third sampling resistor is grounded and connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the second sampling resistor, and the second end of the second sampling resistor is connected to the second input end of the comparison module. According to the above structure, the reference voltage is determined according to the second sampling resistor, the third sampling resistor and the second detection voltage, and is input into the second input end of the comparison module. Since the reference voltage can change with the change of the sampling resistor, compared with a determined pre-driver chip, the overcurrent threshold can be adjusted, thereby improving the ability of the device to drive a load.

[0012] In a possible implementation, the overcurrent protection device further comprises a reset module, the reset module comprises a seventh resistor, an eighth resistor and a third transistor, the controller further comprises a third pin, the first end of the seventh resistor is connected to the third pin, the second end of the seventh resistor is connected to the first end of the eighth resistor and the base of the third transistor, the second end of the eighth resistor is connected to the first detection voltage and the emitter of the third transistor, and the collector of the third transistor is connected to the second end of the fourth resistor.

[0013] In a possible implementation, the control module further includes a fourth pin connected with the second end of the first resistor; and the controller is further configured to, in a case where the voltage sampled by the fourth pin changes from a high level to a low level, control the third transistor in the reset module to be turned on through the third pin, so that the second transistor and the first field effect transistor are turned off, and the output end of the control module outputs a fourth voltage, where the fourth voltage is greater than the third voltage. The reset module can control the state of the first field effect transistor according to the combination of simple elements and the reset signal generated by the controller according to the sampling current, and in a case where the first field effect transistor is turned off, overcurrent protection is achieved, and multiple protection and detection can be performed on overcurrent.

[0014] In a second aspect, the present application provides an overcurrent protection method, which is applied to the overcurrent protection device in the first aspect, and the method includes: a controller acquires a first current, where the first current indicates a total current of one or more loads; in a case where the first current is less than or equal to a first threshold value, the controller determines a third current according to a second current corresponding to a first load, the first load is any one of the one or more loads, and the controller compares the third current with a second threshold value, the second threshold value is any value less than or equal to the first threshold value; and in a case where the third current is greater than the second threshold value, the controller controls the first load to be turned off.

[0015] In a possible implementation, the overcurrent protection method further includes, in a case where the first current is greater than the first threshold value, the controller controls the one or more loads to be turned off.

[0016] In the above process, the controller compares the total current of the one or more loads sampled from the overcurrent protection device through the first pin with an overcurrent value, in a case where the total current is less than or equal to the overcurrent value, the controller determines a third current according to the current corresponding to any one of the loads and a current relationship determined according to an empirical value, and judges whether any one of the loads is overcurrent by comparing the third current with a second threshold value, in a case where the load is overcurrent, the controller controls the overcurrent load to be turned off through the second pin, and the controller can control the one or more loads. In a case where the total current is greater than the overcurrent value, the controller turns off all the loads, and multiple protection can be provided for overcurrent protection of the loads in addition to hardware control of turning off the loads.

[0017] In a possible implementation, the overcurrent protection method further includes: the controller repeatedly acquires the first current; and in a case where the first current is less than or equal to the first threshold value, the controller generates a reset signal to control the overcurrent protection device to be switched from outputting the third voltage to outputting a fourth voltage. After all the loads are turned off, the controller generates a reset signal in a case where the first current acquired again is less than or equal to the first threshold value, so as to control the overcurrent protection device to turn on the loads.

[0018] In a third aspect, the present application provides a vehicle comprising the overcurrent protection device of the first aspect, and the overcurrent protection method of the second aspect is executed.

[0019] On the basis of the implementation manners of the above aspects, the present application can be further combined to provide more implementation manners. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows.

[0021] Figure 1 is a structural schematic diagram of an overcurrent protection device provided by an embodiment of the present application;

[0022] Figure 2 is a structural schematic diagram of a load driving circuit provided by an embodiment of the present application;

[0023] Figure 3 is a structural schematic diagram of a control module provided by an embodiment of the present application;

[0024] Figure 4 is a structural schematic diagram of a reference voltage determination module provided by an embodiment of the present application;

[0025] Figure 5 is a structural schematic diagram of a reset module provided by an embodiment of the present application;

[0026] Figure 6 is a structural schematic diagram of a specific overcurrent protection device provided by an embodiment of the present application;

[0027] Figure 7 is a flowchart of an overcurrent protection method provided by an embodiment of the present application;

[0028] Figure 8 is a structural schematic diagram of a vehicle provided by an embodiment of the present application. DETAILED DESCRIPTION

[0029] At present, automobile manufacturers realize the continuous high-side driving scheme by installing pre-driving chips in each load driving circuit, and realize the overcurrent protection inside the load driving circuit through the pre-driving chip, which is of great significance to vehicle load driving. However, the manufacturing of such chips is monopolized, the cost is high, and the production capacity is limited, which causes a supply gap.

[0030] Therefore, the application provides an overcurrent protection device, which is externally connected to a load driving circuit to realize the function of overcurrent protection without using a pre-driver chip, is composed of simple circuit elements, is simple and reliable, has low cost, can be mass-produced, and meets current production requirements.

[0031] As shown in Figure 1 , Figure 1 is a structural schematic diagram of an overcurrent protection device provided by an embodiment of the application. The device includes a first sampling resistor 10, an amplification module 20, a comparison module 30, and a control module 40. An input power supply is connected to a first end of the first sampling resistor 10, a second end of the first sampling resistor 10 is connected to a first end of each of at least one load, a first input end of the amplification module 20 is connected to the first end of the first sampling resistor 10, a second input end of the amplification module 20 is connected to the second end of the first sampling resistor 10, an output end of the amplification module 20 is connected to a first input end of the comparison module 30, an input end of the control module 40 is connected to an output end of the comparison module 30, and an output end of the control module 40 is connected to a second end of each load.

[0032] The first sampling resistor 10 is configured to input a first voltage obtained by dividing the voltage of the input power supply to the first end of each load. The amplification module 20 is configured to input an amplified voltage obtained by amplifying the input voltage to the first input end of the comparison module 30, wherein the input voltage is the voltage corresponding to the two ends of the first sampling resistor 10, and the amplified voltage is generated by amplifying the input voltage according to the amplification factor of the amplification module 20. The comparison module 30 is configured to compare the amplified voltage and a reference reference voltage, and output a second voltage when it is determined that the amplified voltage is greater than the reference reference voltage at the second input end of the comparison module 30, wherein the second voltage is a high level. The control module 40 is configured to output a third voltage to the second end of each load under the control of the second voltage, so that each load is closed under the action of the first voltage and the third voltage.

[0033] In a specific embodiment, as shown in Figure 2 , Figure 2is a structural schematic diagram of a load driving circuit provided by an embodiment of the present application. A first end (Load A) of the load driving circuit is connected with a second end of a first sampling resistor, and a corresponding voltage is a first voltage. A second end (Load B) of the load driving circuit is connected with an output end of a control module, and a corresponding voltage is a third voltage. The load driving circuit comprises a first load resistor R1 to a seventh load resistor R7, a fourth transistor Q1, a fifth transistor Q2, a second field effect transistor Q3, and a load element. A first end of the first load resistor is connected with the Load A and an emitter of the fourth transistor. A second end of the first load resistor is connected with a base of the fourth transistor and a first end of a second load resistor. A second end of the second load resistor is connected with the Load B. The emitter of the fourth transistor is connected with a first end of a third load resistor and a source of the second field effect transistor. A collector of the fourth transistor is connected with a second end of the third load resistor, a gate of the second field effect transistor, and a first end of a fourth load resistor respectively. A drain of the second field effect transistor is connected with the load element. A second end of the fourth load resistor is connected with a collector of the fifth transistor. An emitter of the fifth transistor is grounded and connected with a second end of a fifth load resistor. A first end of the fifth load resistor is connected with a base of the fifth transistor and a first end of a sixth load resistor. The sixth load resistor is connected with the seventh load resistor. The seventh load resistor is connected with a second pin of a controller.

[0034] In a possible implementation, the load driving circuit further comprises a voltage stabilizing diode D1 and a capacitor C1 connected in parallel with the third load resistor. The voltage stabilizing diode is used to control the voltage in the case that the voltage of the second field effect transistor is too large. The capacitor can delay the conduction of the second field effect transistor in the case of driving the load, and the two together protect the second field effect transistor. The load driving circuit can further comprise a capacitor C2, a resistor R8, and a voltage stabilizing diode D2 connected with the drain of the second field effect transistor. The capacitor, the resistor, and the voltage stabilizing diode are connected in parallel with each other and grounded. The voltage stabilizing diode is used to protect the elements in the load driving circuit. The resistor and the capacitor together play the roles of output filtering and anti-static. In the case that the load element is disconnected, the resistor node can output a clear low level, playing the role of a dummy load. The load driving circuit can further comprise a capacitor C3 connected with a second end of R5 and a second end of R6, used to protect the circuit elements. The load driving circuit can further comprise other connection conditions, and can comprise more or fewer elements. The present application does not make specific limitations thereon, and only takes the above as an example for description. Figure 2

[0035] In the case of load overload, the overcurrent protection device determines the first voltage at the Load A and the third voltage at the Load B as a low level. According to the first voltage, the third voltage, the first load resistor, and the second load resistor, the emitter-base voltage (V EB ) of the fourth transistor is calculated.​EB greater than the turn-on threshold voltage corresponding to the fourth triode, the fourth triode is turned on, at this time, the source-gate voltage (V SG ) of the second field effect transistor is the same as the collector-emitter saturation voltage of the fourth triode , which can be determined according to the element standard table less than the turn-on threshold voltage corresponding to the second field effect transistor, thus the second field effect transistor is turned off, resulting in the output of the load element being closed.

[0036] In a possible implementation, the overcurrent protection device further comprises a controller 50, the controller comprising a first pin 51 and a second pin 52, the first pin being connected to the output end of the amplification module, and each second pin being connected to the third end of any one load, that is, the second end of the seventh load resistor. The controller is configured to control the level output by the second pin according to the current sampled at the output end of the amplification module by the first pin, so as to control the opening or closing of one or more loads.

[0037] When the total current sampled by the first pin is greater than a first threshold value, the load is overloaded, the controller controls the level output by the second pin to be a low level, so as to close all the loads. When the total current sampled by the first pin is less than or equal to the first threshold value, the load is unloaded or always in an unoverloaded state, the controller controls the level output signal of the plurality of second pins according to the current of each load. When the second pin outputs a high level, the controller controls the corresponding load to be opened, and when the second pin outputs a low level, the controller controls the corresponding load to be closed.

[0038] By controlling the opening or closing of the loads by the controller, the control of one or more loads among all the loads can be realized. Compared with determining the voltage by only using circuit elements to control the opening or closing of all the loads, the controller can more flexibly control the loads.

[0039] As Figure 3 shown, Figure 3 is a structural schematic diagram of a control module provided by an embodiment of the present application. In a possible implementation, the control module 40 comprises a first sub-module 41, a second sub-module 42, a third sub-module 43 and a first resistor 44. The first sub-module 41 comprises a second resistor 411 and a first triode 412. The second sub-module 42 comprises a third resistor 421, a fourth resistor 422 and a second triode 423. The third sub-module 43 comprises a fifth resistor 431, a sixth resistor 432 and a first field effect transistor 433.

[0040] The first end of the first resistor 44 is connected with the output end of the comparison module 30, the second end of the first resistor 44 is connected with the base of the first triode 412, the base of the first triode 412 is connected with the first end of the second resistor 411, the second end of the second resistor 411 is connected with the emitter of the first triode 412, the emitter of the first triode 412 is grounded, the collector of the first triode is connected with the second end of the third resistor 421, the first end of the third resistor 421 is connected with the base of the second triode 423, the second end of the fourth resistor 422 is connected with the base of the second triode 423, the first end of the fourth resistor 422 is connected with the first detection voltage, the first end of the fourth resistor 422 is connected with the emitter of the second triode 423, the collector of the second triode 423 is connected with the first end of the fifth resistor 431, the second end of the fifth resistor 431 is connected with the first end of the sixth resistor 432, the second end of the sixth resistor 432 is grounded, the second end of the sixth resistor 432 is connected with the source of the first field effect transistor 433, the gate of the first field effect transistor 433 is connected with the first end of the sixth resistor 432, the drain of the first field effect transistor 433 is connected with the second end of each load.

[0041] In a possible implementation, the control module can further include more or less elements, including more connection relationships, which are not specifically limited in the present application, and are only described here by way of example. Figure 3

[0042] In a possible implementation, the first sub-module is configured to be turned on under the action of the second voltage output by the comparison module; the second sub-module and the third sub-module are configured to be turned on under the action of the first detection voltage in the case that the first sub-module is turned on, so that the drain of the first field effect transistor outputs the third voltage to the second end of each load.

[0043] In a specific implementation, in the case of overcurrent of the load, the amplification voltage is greater than the reference reference voltage, the second voltage output by the comparison module is a high voltage, then according to the second voltage, the first resistor and the second resistor, the base-emitter voltage of the first triode is determined, which is greater than the turn-on voltage threshold of the first triode, and it is determined that the first triode in the first sub-module is turned on. In the case that the first triode is turned on, the first detection voltage is grounded through the fourth resistor and the third resistor, and the emitter-base voltage of the second triode can be calculated, which is greater than the turn-on threshold voltage of the second triode, and it is determined that the second triode in the second sub-module is turned on. In the case that the second triode is turned on, the first detection voltage is grounded through the fifth resistor and the sixth resistor, and the gate-source voltage of the first field effect transistor can be calculated, which is greater than the turn-on threshold voltage of the first field effect transistor, and it is determined that the first field effect transistor in the third sub-module is turned on, the drain of the first field effect transistor is grounded, and the third voltage of low level is output to the second end of each load for turning off the load.​

[0044] In a possible implementation, the overcurrent protection device further comprises a reference voltage determination module, a first end of the reference voltage determination module is connected with the second detection voltage, and a second end of the reference voltage determination module is connected with the second input end of the comparison module; the reference voltage determination module is configured to convert the second detection voltage into a reference voltage input into the second input end of the comparison module.

[0045] As shown in Figure 4 , Figure 4 is a structural diagram of a reference voltage determination module provided by an embodiment of the present application. The reference voltage determination module 60 comprises a second sampling resistor 61, a third sampling resistor 62, and a first capacitor 63. The first end of the second sampling resistor 61 is connected with the second detection voltage, the second end of the second sampling resistor 61 is connected with the second end of the third sampling resistor 62, the first end of the third sampling resistor 62 is grounded and connected with the first end of the first capacitor 63, the second end of the first capacitor 63 is connected with the first end of the second sampling resistor 61, and the second end of the second sampling resistor 61 is connected with the second input end of the comparison module.

[0046] The reference voltage is determined according to the second sampling resistor and the third sampling resistor and input into the second input end of the comparison module, for comparison with the amplified voltage, so as to control the second voltage and the third voltage and realize overcurrent protection. Compared with the existing determined pre-driver chip, the present application can adjust the driving load capacity by adjusting the reference voltage, and the control is more flexible.

[0047] The first detection power supply and the second detection power supply mentioned in the above device can be turned off in the case of no overcurrent detection, so as to reduce energy consumption.

[0048] In a possible implementation, the overcurrent protection device further comprises a reset module, as shown in Figure 5 , Figure 5 is a structural diagram of a reset module provided by an embodiment of the present application. The reset module 70 comprises a seventh resistor 71, an eighth resistor 72, and a third transistor 73. The controller further comprises a third pin 53, the first end of the seventh resistor 71 is connected with the third pin 53, the second end of the seventh resistor 71 is connected with the first end of the eighth resistor 72 and the base of the third transistor 73, the second end of the eighth resistor 72 is connected with the first detection voltage, the emitter of the third transistor 73 is connected, and the collector of the third transistor 73 is connected with the second end of the fourth resistor.

[0049] The control module further comprises a fourth pin 54 connected with the second end of the first resistor; and the controller is further configured to, in a case where the voltage sampled by the fourth pin changes from high level to low level or in a case where the current sampled by the first pin is less than or equal to the overcurrent value, control the third transistor in the reset module to be turned on through the third pin, so that the second transistor and the first field effect transistor are turned off, and the output end of the control module outputs a fourth voltage, which is greater than the third voltage.

[0050] In a possible implementation, in the case where the voltage sampled by the fourth pin changes from high level to low level or in the case where the current sampled by the first pin is less than or equal to the overcurrent value, the controller sends a low-level reset signal through the third pin, and then the emitter-base voltage (V EB ) of the third transistor can be calculated according to the first detection voltage, the seventh resistor and the eighth resistor. At this time, V EB is greater than the turn-on threshold voltage of the third transistor, and thus the third transistor is turned on. In the case where the third transistor is turned on, the base-emitter voltage of the second transistor is determined according to the corresponding collector-emitter saturation voltage of the transistor, and at this time, the base-emitter voltage of the second transistor is less than the turn-on threshold voltage of the second transistor, and thus the second transistor is turned off. The turning off of the second transistor causes the gate of the first field effect transistor to be grounded, and thus the first field effect transistor is also turned off, and the output end of the control module changes from outputting the third voltage to outputting the fourth voltage, and changes from outputting low level to outputting high level, so as to turn on the second field effect transistor in the load driving circuit. The controller can turn on one or more loads by controlling the second pin.

[0051] In a possible implementation, the first sampling resistor in the overcurrent protection device is a four-milliohm resistor, which can make the current detected in the overcurrent detection process more accurate and ensure smaller power consumption and heat dissipation. The first sampling resistor can also be a larger or smaller resistor, which is not limited in the present application.

[0052] In a possible implementation, the overcurrent protection device further comprises a filter circuit and a voltage follower. Two input ends of the filter circuit are connected with the first end and the second end of the first sampling resistor 10 respectively, two output ends are connected with the first input end and the second input end of the amplification module 20 respectively, the input end of the voltage follower is connected with the output end of the amplification module 20, and the output end is connected with the first input end of the comparison module 30. The overcurrent protection device can further comprise more elements, which are not limited in the present application.

[0053] In a possible implementation, the signal ground in the overcurrent protection device and the power ground in the load driving circuit are separated and connected together through a magnetic bead and a capacitor, so that the overcurrent protection device can be prevented from being affected by the overload or unloading of the load.

[0054] In the above process, the first end of all elements is the left end of the horizontally placed element, and the upper end of the vertically placed element, and the second end of all elements is the right end of the horizontally placed element, and the lower end of the vertically placed element, and the specific connection relationship is shown in the figure.

[0055] As Figure 6 shown, Figure 6 is a specific overcurrent protection device structure schematic diagram provided by the embodiment of the application, and the specific connection relationship is shown in Figure 1 , Figure 3 , Figure 4 and Figure 5 the same, which will not be described one by one here.

[0056] In a specific embodiment, the overcurrent protection device obtains the total current of the multiple loads through Load A, determines the input voltage of the amplification module according to the total current of the multiple loads and a first sampling resistor, where the first sampling resistor is four milliohms, the amplification factor of the amplification module is fifty, and the output amplified voltage is equal to fifty times the input voltage. The controller can sample the amplified voltage through the first pin to avoid the problem that the input voltage is too small and the controller cannot detect. Then, the voltage follower is used to input the amplified voltage to the first input end of the comparison module, the comparison module compares the amplified voltage with the reference level, and outputs a high level of 5V when the amplified voltage is greater than the reference level. The 5V voltage is divided by the first resistor (2KΩ) and the second resistor (20KΩ), and the base-emitter voltage of the first transistor can be calculated to be 4.55V. Since the conduction threshold voltage of the first transistor is determined according to the first transistor standard, the conduction threshold voltage of the first transistor is between 0.65V and 0.95V, which is less than 4.55V, and the first transistor is turned on. The first detection voltage (5V) is grounded through the third resistor (10KΩ), the fourth resistor (10KΩ) and the first transistor, and the emitter-base voltage of the second transistor is calculated to be 2.025V, which is greater than the conduction threshold voltage of the emitter-base of the second transistor, and the second transistor is turned on. Thus, the gate-source voltage of the first field effect transistor can be determined according to the first detection voltage (5V), the fifth resistor (2KΩ) and the sixth resistor (47KΩ) to be 4.12V, which is greater than the conduction threshold voltage of the first field effect transistor, and the first field effect transistor is turned on. The Load B connected to the first field effect transistor is grounded to provide a low level to the second end of the load driving circuit. The load driving circuit calculates the emitter-base voltage of the fourth transistor according to the voltage of Load A obtained by dividing the input power supply through the first sampling resistor, the voltage of Load B, the first load resistor and the second load resistor, and determines that the fourth transistor is turned on. In the case that the fourth transistor is turned on, the gate-source voltage of the second field effect transistor is equal to the saturation voltage of the collector and the emitter of the fourth transistor, which is less than the conduction threshold voltage of the second field effect transistor, and the second field effect transistor changes from the on state to the off state to make the load element connected to the drain of the second field effect transistor off output.

[0057] In summary, the overcurrent protection device provided by the present application controls the voltage input to the load driving circuit by combining simple elements, thereby controlling the opening and closing of the load and realizing the function of overcurrent protection. The process of building the overcurrent protection device with simple elements is simple, the cost is low, mass production is possible, and the problem of insufficient production capacity of the pre-driver chip is solved.

[0058] As shown in Figure 7 , Figure 7 is a flow chart of an overcurrent protection method provided by an embodiment of the present application. The method is applied to the above Figure 1 and Figure 6The method comprises the following steps in the overcurrent protection device shown.

[0059] Step S710: The controller acquires a first current, wherein the first current indicates a total current of one or more loads.

[0060] The controller samples the first current from the overcurrent protection device through a first pin, wherein the first current indicates a total current of one or more loads.

[0061] Step S720: The controller compares the first current with a first threshold value, and executes step S730 in the case that the first current is less than or equal to the first threshold value, or closes all circuits in the one or more loads in the case that the first current is greater than the first threshold value, wherein the first threshold value is a determined load overcurrent value.

[0062] Step S730: The controller determines a third current according to a second current corresponding to a first load of the one or more loads, and compares the third current with a second threshold value, wherein the first load is any one of the one or more loads, and the second threshold value is any value less than or equal to the first threshold value.

[0063] After acquiring the first current, the controller determines the second current corresponding to the first load, and determines the third current according to the second current and an overcurrent judgment relationship of the first load determined according to an empirical value in advance, wherein the third current is greater than the second current. Then, the controller compares the third current with the second threshold value, and determines that the first load is overloaded in the case that the third current is greater than the second threshold value, and executes step S740, or determines that the first load is not overloaded in the case that the third current is less than or equal to the second threshold value, and still controls the load to remain in an open state.

[0064] Since there is a case that the total current of the one or more loads is still less than or equal to the first threshold value when the one or more loads are overloaded, the controller can determine whether each load is overloaded according to the current corresponding to each load, so as to improve the overcurrent protection effect and protect the loads and elements.

[0065] Step S740: The controller controls the first load to be closed.

[0066] The controller determines whether each load of the one or more loads is overloaded according to step S730, and controls the load to be closed through a second pin connected to each overloaded load.

[0067] In a possible implementation, the overcurrent protection method further comprises: the controller repeatedly acquires the first current, and generates a reset signal to make the overcurrent protection device change from outputting the third voltage to outputting a fourth voltage in the case that the load is unloaded and the first current is less than or equal to the first threshold value.

[0068] In summary, the controller samples the total current of one or more loads from the overcurrent protection device through the first pin, determines the current of each load, and determines whether each load is overcurrent according to the current of each load and a relationship determined according to an empirical value. In the case of overcurrent, the controller controls the overcurrent load or loads to be turned off through the second pin, thereby achieving multiple overcurrent protection.

[0069] As shown in Figure 8 , Figure 8 is a structural diagram of a vehicle provided by an embodiment of the application, which includes the overcurrent protection device shown in Figure 1 , Figures 3 to 6 .

[0070] The above embodiments only describe the preferred embodiments of the application, and do not limit the scope of the application. Without departing from the design spirit of the application, various modifications and improvements to the technical solutions of the application made by those skilled in the art shall fall within the protection scope determined by the claims of the application.

Claims

1. An overcurrent protection device, characterized in that, The device includes a first sampling resistor, an amplification module, a comparison module, a control module, and a controller. An input power supply is connected to a first terminal of the first sampling resistor. A second terminal of the first sampling resistor is connected to a first terminal of each of at least one load. A first input terminal of the amplification module is connected to a first terminal of the first sampling resistor. A second input terminal of the amplification module is connected to a second terminal of the first sampling resistor. An output terminal of the amplification module is connected to a first pin of the controller. One of the plurality of second pins of the controller is connected to one of the at least one load. The first sampling resistor is used to input the first voltage obtained by voltage division of the input power supply to the first terminal of each load; The amplification module is used to input the amplified voltage after amplifying the input voltage to the first input terminal of the comparison module; The comparison module is used to output a second voltage when it is determined that the amplified voltage is greater than the reference voltage at the second input terminal of the comparison module; The control module is configured to output a third voltage to the second terminal of each load under the control of the second voltage, so that each load is turned off under the action of the first voltage and the third voltage; The controller is used to control the opening or closing of one or more loads based on the current sampled by the first pin at the output terminal of the amplification module. When the current sampled by the first pin at the output terminal of the amplification module is greater than a first threshold, the controller controls one or more second pins to output a low-level signal. The first threshold is determined based on the reference voltage, the amplification module, and the first sampling resistor.

2. The apparatus according to claim 1, characterized in that, The control module includes a first resistor, a first submodule, a second submodule, and a third submodule. The first submodule includes a second resistor and a first transistor. The second submodule includes a third resistor, a fourth resistor, and a second transistor. The third submodule includes a fifth resistor, a sixth resistor, and a first field-effect transistor. The first end of the first resistor is connected to the output of the comparator module, the second end of the first resistor is connected to the second resistor and the base of the first transistor; the second end of the third resistor is connected to the collector of the first transistor, the fourth resistor and the emitter of the second transistor are connected to the first detection voltage; the fifth resistor is connected to the collector of the second transistor, and the drain of the first field-effect transistor is connected to the second end of each load. The first submodule is used to be turned on under the action of the second voltage output by the comparison module; The second submodule and the third submodule are used to conduct under the action of the first detection voltage when the first submodule is turned on, so that the drain of the first field-effect transistor outputs the third voltage to the second terminal of each load.

3. The apparatus according to claim 2, characterized in that, The second terminal of the second resistor is connected to the emitter of the first transistor, the emitter of the first transistor is grounded, the collector of the first transistor is connected to the second terminal of the third resistor, the first terminal of the third resistor is connected to the base of the second transistor, the second terminal of the fourth resistor is connected to the base of the second transistor, the first terminal of the fourth resistor is connected to the emitter of the second transistor, the second terminal of the fifth resistor is connected to the first terminal of the sixth resistor, the second terminal of the sixth resistor is grounded, the second terminal of the sixth resistor is connected to the source of the first field-effect transistor, and the gate of the first field-effect transistor is connected to the first terminal of the sixth resistor.

4. The apparatus according to claim 3, characterized in that, The device further includes a reference voltage determination module, wherein a first terminal of the reference voltage determination module is connected to a second detection voltage, and a second terminal of the reference voltage determination module is connected to a second input terminal of the comparison module. The reference voltage determination module is used to convert the second detected voltage into the reference voltage and input it into the second input terminal of the comparison module.

5. The apparatus according to claim 4, characterized in that, The reference voltage determination module includes a second sampling resistor, a third sampling resistor, and a first capacitor. The first end of the second sampling resistor is connected to the second detected voltage, the second end of the second sampling resistor is connected to the second end of the third sampling resistor, the first end of the third sampling resistor is grounded and connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the second sampling resistor, and the second end of the second sampling resistor is connected to the second input terminal of the comparison module.

6. The apparatus according to claim 5, characterized in that, The device also includes a reset module, which includes a seventh resistor, an eighth resistor, and a third transistor. The controller further includes a third pin, which is connected to the first end of the seventh resistor. The second end of the seventh resistor is connected to the first end of the eighth resistor and to the base of the third transistor. The second end of the eighth resistor is connected to the first detection voltage and to the emitter of the third transistor. The collector of the third transistor is connected to the second end of the fourth resistor.

7. The apparatus according to claim 6, characterized in that, The control module further includes a fourth pin, which is connected to the second end of the first resistor; The controller is further configured to, when the voltage sampled by the fourth pin changes from high level to low level, or when the current sampled by the first pin is less than or equal to the overcurrent value, control the third transistor in the reset module to turn on via the third pin, thereby turning off the second transistor and the first field-effect transistor, and causing the output terminal of the control module to output a fourth voltage, the fourth voltage being greater than the third voltage.

8. An overcurrent protection method, characterized in that, The method is applied to the overcurrent protection device as described in any one of claims 1-7, comprising: The controller acquires a first current, which indicates the total current of the one or more loads; When the first current is less than or equal to the first threshold, the controller determines the third current based on the second current corresponding to the first load, where the first load is any one of the one or more loads; The controller compares the third current with a second threshold, which is any value that is less than or equal to the first threshold; If the third current is greater than the second threshold, the controller controls the first load to shut down.

9. The method according to claim 8, characterized in that, The method further includes: If the first current is greater than the first threshold, the controller controls one or more loads to be shut down.

10. The method according to claim 9, characterized in that, The method further includes: The controller repeatedly acquires the first current; When the first current is less than or equal to the first threshold, the controller generates a reset signal to cause the overcurrent protection device to switch from outputting a third voltage to outputting a fourth voltage.

11. A vehicle, characterized in that, The vehicle includes an overcurrent protection device as described in any one of claims 1 to 7.

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