Short circuit protection system and battery management system

Abstract

A battery management system includes a switch, a processor, and a bias detection circuit. The switch is electrically connected between the load and the battery. The processor is electrically connected to the switch and is used for obtaining the temperature value of the battery. The bias voltage detection circuit is electrically connected to the switch and the processor and is used for detecting the cross voltage of the switch. The processor sets the working state of the bias detection circuit according to the positions of the temperature values in the plurality of temperature intervals. The bias voltage detection circuit generates an interrupt signal to the processor according to the working state and the cross voltage. The processor controls the switch according to the interrupt signal. The cross-pressure is associated with the positions of the temperature values in a plurality of temperature intervals. The short-circuit protection system and the battery management system can adaptively select a proper voltage threshold value to carry out short-circuit protection according to the working temperature under the condition of low temperature, normal temperature or high temperature, so that the damage caused by short-circuit current is reduced.

Description

Technical Field

[0001] The invention relates to a battery management system, in particular to a battery management system applied to short circuit protection. Background Art

[0002] In response to the short-circuit current generated by the battery due to load failure, the electronic devices on the market mainly perform relevant short-circuit protection mechanisms by detecting the cross-voltage of the shunt resistor or the cross-voltage of the power transistor. In detail, when the cross-voltage exceeds a certain fixed preset critical value, the electronic device will disconnect the power transistor through the microcontroller to prevent the short-circuit current of the battery from damaging the electronic device. However, the electronic characteristics of the shunt resistor and the transistor (for example, the current-voltage characteristics) will change with temperature. Therefore, when the operating temperature of the electronic device changes, the fixed preset critical value in the traditional short-circuit protection mechanism may cause the electronic device to misjudge whether a short circuit has occurred. In other words, the traditional short-circuit protection mechanism is not suitable for different operating temperature ranges, making the electronic device easily damaged by the short-circuit current.

[0003] Therefore, the above technology still has many defects, and practitioners in this field need to develop other suitable battery management systems. Summary of the invention

[0004] One aspect of the present case relates to a short-circuit protection system. The short-circuit protection system is applied to an electronic device. The electronic device has a switch. The switch is used to conduct or disconnect the electrical connection between the electronic device and an external load. The short-circuit protection system includes a protection circuit and a controller. The protection circuit is used to detect the cross-voltage of the switch and includes multiple voltage thresholds corresponding to multiple temperature intervals. The controller is used to obtain the temperature value of the electronic device and select a corresponding one of the multiple voltage thresholds of the protection circuit according to the temperature value. When the cross-voltage is greater than one of the multiple voltage thresholds, the switch enables the protection circuit to output an interrupt signal to the controller. When the controller receives the interrupt signal, the controller disconnects the switch.

[0005] In one embodiment, when the voltage across the switch changes from less than one of the voltage thresholds to greater than one of the voltage thresholds, the protection circuit switches the voltage provided to the controller from a first level to a second level to output an interrupt signal.

[0006] In one embodiment, the protection circuit includes a plurality of amplifiers, a multiplexer, and a comparator. The plurality of amplifiers are used to amplify the cross-voltage. The plurality of amplifiers correspond to a plurality of temperature ranges, respectively, and have different gains. The multiplexer includes a plurality of input terminals, and the plurality of input terminals are electrically connected to the plurality of amplifiers. The processor is used to control the output voltage of one of the plurality of amplifiers output by the multiplexer according to the temperature value of the electronic device, thereby setting the voltage threshold of the protection circuit. The comparator is electrically connected to the processor and the multiplexer, and is used to compare the output voltage with the preset voltage to determine the voltage level of the interrupt signal.

[0007] In one embodiment, the plurality of temperature intervals correspond to a mapping relationship between a protection current temperature curve and an operating current temperature curve of the switch. A point corresponding to a temperature in the protection current temperature curve is greater than a point corresponding to a temperature in the operating current temperature curve. The protection current temperature curve includes an initial point corresponding to a preset temperature value of the battery. Horizontal mapping and vertical mapping are sequentially performed between the protection current temperature curve and the operating current temperature curve from the initial point of the protection current temperature curve to obtain a plurality of horizontal line segments and a plurality of vertical line segments. The plurality of horizontal line segments and the plurality of vertical line segments are alternately connected to each other. The plurality of horizontal line segments are a plurality of temperature intervals.

[0008] Another aspect of the present case relates to a battery management system. The battery management system includes a switch, a processor, and a bias detection circuit. The switch is electrically connected between a load and a battery. The processor is electrically connected to the switch and is used to obtain a temperature value of the battery. The bias detection circuit is electrically connected to the switch and the processor and is used to detect a cross-voltage of the switch. The processor sets the working state of the bias detection circuit according to the position of the temperature value in multiple temperature intervals. The bias detection circuit generates an interrupt signal to the processor based on the working state and the cross-voltage. The processor controls the switch according to the interrupt signal. The cross-voltage is associated with the position of the temperature value in multiple temperature intervals.

[0009] In one embodiment, the bias detection circuit includes a plurality of amplifiers, a multiplexer, and a comparator. The plurality of amplifiers are used to amplify the cross-voltage. The plurality of amplifiers correspond to a plurality of temperature ranges, respectively, and have different gains. The multiplexer includes a plurality of input terminals. The plurality of input terminals are electrically connected to the plurality of amplifiers. The processor is used to control the output voltage of one of the plurality of amplifiers output by the multiplexer according to the temperature value of the battery, and then set as the working state of the bias detection circuit. The comparator is electrically connected to the processor and the multiplexer, and is used to compare the output voltage with the preset voltage to determine the voltage level of the interrupt signal.

[0010] In one embodiment, the switch includes a transistor. The transistor includes a drain terminal, a source terminal and a gate terminal. The plurality of amplifiers are electrically connected to the drain terminal and the source terminal of the transistor respectively, and the gate terminal of the transistor is electrically connected to the processor.

[0011] In one embodiment, when the output voltage is greater than a preset voltage, the processor turns off the switch, and when the output voltage is less than or equal to the preset voltage, the processor turns on the switch.

[0012] In one embodiment, the plurality of temperature intervals correspond to a mapping relationship between a protection current temperature curve and an operating current temperature curve of the switch, and a point corresponding to a temperature in the protection current temperature curve is greater than a point corresponding to a temperature in the operating current temperature curve. The protection current temperature curve includes an initial point corresponding to a preset temperature value of the battery. From the initial point of the protection current temperature curve, horizontal mapping and vertical mapping are sequentially performed between the protection current temperature curve and the operating current temperature curve to obtain a plurality of horizontal line segments and a plurality of vertical line segments, the plurality of horizontal line segments and the plurality of vertical line segments are alternately connected to each other, and the plurality of horizontal line segments are a plurality of temperature intervals.

[0013] In one embodiment, the number of the plurality of temperature intervals is proportional to the number of the plurality of amplifiers.

[0014] The short-circuit protection system and battery management system of the above-mentioned embodiments adaptively select an appropriate voltage threshold for short-circuit protection according to the operating temperature, and select an appropriate voltage threshold for short-circuit protection under low temperature, normal temperature or high temperature conditions to reduce the damage caused by the short-circuit current. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The content of this case can be better understood by referring to the embodiments in the subsequent paragraphs and the following drawings:

[0016] Figure 1 is a simplified functional block diagram of a short circuit protection system and an electronic device according to an embodiment of the present invention;

[0017] Figure 2 is a circuit diagram of a short circuit protection system and an electronic device according to an embodiment of the present invention;

[0018] Figure 3 is a circuit block diagram of a battery management system according to an embodiment of the present invention;

[0019] Figure 4 is a circuit block diagram of a battery management system according to an embodiment of the present invention; and

[0020] Figure 5 FIG. 1 is a schematic diagram of a protection current-temperature curve and an operating current-temperature curve of a switch according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] Figure 11 is a simplified functional block diagram of a short circuit protection system 100 and an electronic device 900 according to an embodiment of the present invention. The electronic device 900 includes a switch 910 and a power source 920. The switch 910 is electrically connected between a load 700 outside the electronic device 900 and the power source 920, and is used to conduct or disconnect the electrical connection with the load 700. The power source 920 is used to provide the voltage and current required by the load 700. In one embodiment, the electronic device 900 may be a power supply or a battery module. In some embodiments where the electronic device 900 is implemented by a battery module, the power source 920 includes a lithium battery pack or a lead-acid battery pack.

[0022] In one embodiment, the short circuit protection system 100 includes a protection circuit 110 and a controller 120. The protection circuit 110 is electrically connected to the controller 120 and a switch 910 of the electronic device 900. The controller 120 is electrically connected to the switch 910 and a power source 920 of the electronic device 900.

[0023] In one embodiment, the protection circuit 110 is used to detect the voltage across the input and output ends of the switch 910. The protection circuit 110 includes a plurality of voltage thresholds, wherein the voltage thresholds correspond to a plurality of temperature intervals when the electronic device 900 is operating. The controller 120 obtains the current temperature value of the electronic device 900 and determines which of the aforementioned plurality of temperature intervals the temperature value is located in, and then sets the protection circuit 110 to select a corresponding one of the plurality of voltage thresholds to compare with the voltage across the switch 910 to generate a comparison result. The protection circuit 110 outputs an interrupt signal to the controller 120 based on the comparison result, thereby notifying the controller 120 whether to stop turning on the switch 910.

[0024] For example, when the voltage across the switch 910 changes from less than the selected voltage threshold to greater than the selected voltage threshold, the voltage across the switch 910 enables the protection circuit 110 to output an interrupt signal to the controller 120. When the controller 120 receives the interrupt signal, the controller 120 disconnects the switch 910. The aforementioned output of the interrupt signal may refer to the protection circuit 110 switching the voltage provided to the controller 120 from a first level (e.g., a low voltage) to a second level (e.g., a high voltage). Conversely, when the voltage across the switch 910 is less than or equal to the selected voltage threshold, the protection circuit 110 may maintain the voltage provided to the controller 120 at the first level (e.g., a low voltage) to avoid outputting the interrupt signal.

[0025] See also Figure 1In some embodiments, the controller 120 may include but is not limited to a single processor and an integration of multiple microprocessors, such as a central processing unit (CPU) or an application specific integrated circuit (ASIC).

[0026] Figure 2 According to an embodiment of the present invention, Figure 1 The short circuit protection system 100 and the circuit diagram of the electronic device 900 are shown in FIG. Figure 2 , the switch 910 of the electronic device 900 includes a transistor T1. The first end S (e.g., source end) of the transistor T1 is electrically connected to the load 700. The second end D (e.g., drain end) of the transistor T1 is electrically connected to the power source 920. The control end G (e.g., gate end) of the transistor T1 is electrically connected to the controller 120, and is turned on or off in response to the voltage level of the control signal of the controller 120. In one embodiment, when the current I flows from the power source 920 to the load 700 through the transistor T1, the voltage between the first end S and the second end D of the transistor T1 is the voltage between the input end and the output end of the electronic device 900.

[0027] See also Figure 2 The protection circuit 110 of the short circuit protection system 100 includes a plurality of amplifiers (eg, amplifiers 111A to 111D), a multiplexer 112 and a comparator 113 .

[0028] Each of the amplifiers 111A-111D is electrically connected to the first end S and the second end D of the transistor T1 of the switch 910. The amplifiers 111A-111D correspond to multiple temperature ranges when the electronic device 900 is working, and have different gains. By amplifying the voltage across the transistor T1 by different multiples and then transmitting it to the comparator 113, it is equivalent to comparing the voltage across the transistor T1 with different voltage thresholds, which will be described in detail in the following paragraphs.

[0029] In some embodiments, the amplifiers 111A to 111D are differential amplifiers. The amplifier 111A includes resistors R1a to R4a and an operational amplifier OP1. The resistor R1a is electrically connected between the inverting input terminal of the operational amplifier OP1 and the first terminal of the transistor T1. The resistor R2a is electrically connected between the inverting input terminal and the output terminal of the operational amplifier OP1. The resistor R3a is electrically connected between the non-inverting input terminal of the operational amplifier OP1 and the second terminal of the transistor T1. The resistor R4a is electrically connected between the non-inverting input terminal of the operational amplifier OP1 and the ground terminal. The gain of the amplifier 111A can be determined by the values ​​of the resistors R2a, R1a, R3a, and R4a.

[0030] Amplifier 111B includes resistors R1b to R4b and an operational amplifier OP2. Amplifier 111C includes resistors R1c to R4c and an operational amplifier OP3. Amplifier 111D includes resistors R1d to R4d and an operational amplifier OP4. The connection method and gain design method of amplifiers 111B to 111D are similar to those of amplifier 111A. For the sake of brevity, they are not described here. The number of amplifiers 111A to 111D can be designed according to actual needs and is not limited to this embodiment. The details of the number design of amplifiers 111A to 111D will be discussed in the following paragraphs. Figure 5 illustrate.

[0031] The multiple input terminals of the multiplexer 112 are electrically connected to the output terminals of the amplifiers 111A-111D respectively. When the controller 120 sets the voltage threshold selected by the protection circuit 110 according to the temperature value of the electronic device 900, the controller 120 controls the multiplexer 112 to output the output voltage of a corresponding one of the amplifiers 111A-111D to the comparator 113 according to the temperature value of the electronic device 900.

[0032] The comparator 113 includes a resistor R2, a resistor R3 and an operational amplifier OP5. The first end of the resistor R2 receives a preset voltage Vref. The second end of the resistor R2 is electrically connected to the inverting input end of the operational amplifier OP5. The first end of the resistor R3 is electrically connected to the inverting input end of the operational amplifier OP5. The second end of the resistor R3 is grounded. The operational amplifier OP5 is used to compare the output voltage of the multiplexer 112 and the preset voltage Vref (after voltage division) to output a corresponding comparison result at the output end of the operational amplifier OP5 to generate an interrupt signal. When the output voltage of the multiplexer 112 is greater than the preset voltage Vref (after voltage division), the output voltage of the operational amplifier OP5 is switched from a first level (e.g., a low voltage) to a second level (e.g., a high voltage) to output an interrupt signal. The comparison result is that when the output voltage of the multiplexer 112 is less than or equal to the preset voltage Vref (after voltage division), the output voltage of the operational amplifier OP5 is maintained at the first level (e.g., a low voltage).

[0033] In some embodiments, since the preset voltage Vref (after voltage division) is a constant voltage, the case where the voltage across the transistor T1 output by the multiplexer 112 has a higher magnification, is equivalent to comparing the voltage across the transistor T1 with a smaller voltage threshold. Conversely, the case where the voltage across the transistor T1 output by the multiplexer 112 has a lower magnification, is equivalent to comparing the voltage across the transistor T1 with a larger voltage threshold.

[0034] Figure 3The figure is a simplified functional block diagram of a battery management system 200 according to an embodiment of the present invention. The battery management system 200 includes a switch 210, a processor 220, and a bias voltage detection circuit 230. The switch 210 is electrically connected between the load 300 and the battery 500. The processor 220 is electrically connected to the switch 210 and is used to obtain the temperature value of the battery 500. The bias voltage detection circuit 230 is electrically connected to the switch 210 and the processor 220 and is used to detect the cross voltage of the switch 210. The processor 220 is used to set the working state of the bias voltage detection circuit 230 according to the position of the temperature value in multiple temperature intervals, wherein the cross voltage of the switch 210 is associated with the position of the temperature value of the battery 500 in multiple temperature intervals. The bias voltage detection circuit 230 is used to generate an interrupt signal to the processor 220 according to the working state and the cross voltage of the switch 210. The processor 220 is also used to control the switch 210 according to the interrupt signal.

[0035] Figure 4 According to an embodiment of the present invention, Figure 3 The connection and operation of the switch 210, the processor 220 and the bias detection circuit 230 of the battery management system 200 are similar to those of Figure 2 The switch 910 of the electronic device 900, the controller 120 of the short circuit protection system 100 and the protection circuit 110. In addition, the bias detection circuit 230 includes amplifiers 231A-231D, a multiplexer 232 and a comparator 233. The connection methods and operations of the amplifiers 231A-231D, the multiplexer 232 and the comparator 233 are similar to Figure 2 The amplifiers 111A-111D, the multiplexer 112 and the comparator 113 are shown in FIG. For the sake of brevity, only the differences are described below.

[0036] In some embodiments, the "working state" of the bias detection circuit 230 refers to the bias detection circuit 230 selecting a corresponding one from a plurality of voltage thresholds corresponding to a plurality of temperature intervals to compare with the voltage across the switch 210. In other words, the processor 220 sets the working state of the bias detection circuit 230, which can be understood as the processor 220 setting the voltage threshold selected by the bias detection circuit 230. More specifically, the processor 220 is used to control the output voltage of one of the output amplifiers 231A-231D of the multiplexer 232 according to the temperature value of the battery 500, thereby setting the working state of the bias detection circuit 230.

[0037] Compare Figures 1-2 and Figures 3-4 , it can be known that Figures 1-2 The switch 910 and the power supply 920 are packaged as the same electronic device 900, and in Figures 3-4The switch 210 , the processor 220 , and the bias detection circuit 230 are packaged into the same battery management system 200 .

[0038] Figure 5 FIG. 1 is a schematic diagram of a protection current temperature curve L1 and an operating current temperature curve L2 of a switch 910 of an electronic device 900 or a switch 210 of a battery management system 200 according to an embodiment of the present invention. Figure 5 The vertical axis is the voltage across the switch 910 or the switch 210 (denoted by “V DS ”), and Figure 5 The horizontal axis is the operating temperature of the power source 920 or the battery 500 of the electronic device 900 .

[0039] The "multiple temperature intervals" in the above-mentioned multiple embodiments are defined by the mapping relationship between the protection current temperature curve L1 and the working current temperature curve L2. The protection current temperature curve L1 represents the corresponding relationship between the voltage across the switch 910 or the switch 210 and the temperature at different temperatures when an abnormal current that should perform circuit breaking protection is applied to the switch 910 or the switch 210. The working current temperature curve L2 represents the corresponding relationship between the voltage across the switch 910 or the switch 210 and the temperature at different temperatures when the maximum current that can be maintained in normal operation is applied to the switch 910 or the switch 210. A point in the protection current temperature curve L1 corresponding to a certain temperature is greater than the point in the working current temperature curve L2 corresponding to the temperature. In one embodiment, please refer to Figure 5 , the upper limit of the protection current of the protection current temperature curve L1 is 600 amperes (A). The upper limit of the working current of the working current temperature curve L2 is 400 amperes (A). The current values ​​used when drawing the current protection curve L1 and the working current temperature curve L2 (i.e., the current values ​​of points P1 to P7, the initial point A, the intersection point C', and the intersection point D) are only examples, and the present invention is not limited thereto. In some embodiments, the current values ​​applied when drawing the current protection curve L1 and the working current temperature curve L2 can be 90% and 50% of the magnitude of the current I when a short circuit event occurs, respectively.

[0040] In one embodiment, the number of the plurality of temperature intervals is proportional to the number of the plurality of amplifiers (e.g., the amplifiers 111A-111D of the protection circuit 110 or the amplifiers 231A-231D of the bias detection circuit 230). In one embodiment, the number of the plurality of temperature intervals is the same as the number of the plurality of amplifiers (e.g., the amplifiers 111A-111D of the protection circuit 110 or the amplifiers 231A-231D of the bias detection circuit 230). How the number of the plurality of temperature intervals and the number of the plurality of amplifiers are determined will be described in the following paragraphs.

[0041] First, the number of multiple temperature intervals is determined by the mapping relationship between the protection current temperature curve L1 and the working current temperature curve L2. The protection current temperature curve L1 includes an initial point A. For example, the initial point A can be a point on the protection current temperature curve L1 corresponding to a preset temperature value (e.g., the minimum working temperature of -30°C). It should be noted that the preset temperature value can be designed according to actual needs and is not limited to this embodiment.

[0042] Next, see Figure 5 Under the condition of a preset temperature value of -30°C, by taking the initial point A of the protection current temperature curve L1 as the starting point, horizontal mapping and vertical mapping are sequentially performed between the protection current temperature curve L1 and the working current temperature curve L2 to obtain a plurality of horizontal line segments and a plurality of vertical line segments. The plurality of horizontal line segments and the plurality of vertical line segments are alternately connected to each other.

[0043] In detail, the user takes the initial point A of the protection current temperature curve L1 as the starting point and maps it horizontally to the working current temperature curve L2 to obtain the intersection point A'. Then, the user maps the intersection point A' of the working current temperature curve L2 vertically to the protection current temperature curve L1 to obtain the intersection point B. Furthermore, the user maps the intersection point B of the protection current temperature curve L1 horizontally to the working current temperature curve L2 to obtain the intersection point B'. By analogy, the user further obtains the intersection point C, the intersection point C' and the intersection point D.

[0044] It is worth mentioning that the temperature corresponding to the intersection point of the working current temperature curve L2 when the user uses the intersection point D as a reference for horizontal mapping will exceed the maximum working temperature of the power supply 920 or the battery 500 (i.e., the upper limit point E, for example, 45°C). Therefore, the user no longer needs to perform horizontal mapping or vertical mapping to find the intersection point.

[0045] Next, the user uses the horizontal line segment formed by the initial point A and the intersection point A' The corresponding temperature range is about -30℃ to -26℃. The horizontal line segment formed by the intersection point B and the intersection point B' The corresponding temperature range is about -26°C to -17°C. The horizontal line segment formed by the intersection point C and the intersection point C' The corresponding temperature range is about -17°C to 0°C. The horizontal line segment formed by the intersection point D and the maximum operating temperature of the power source 920 or the battery 500 The corresponding temperature range is approximately 0°C to 45°C.

[0046] In summary, since a total of 4 temperature intervals (i.e. horizontal line segments) are obtained through the above operations, Horizontal line segment Horizontal line segment and horizontal line segments ), the number of amplifiers 111A-111D of the protection circuit 110 (or the number of amplifiers 231A-231D of the bias detection circuit 230) can be set to 4 accordingly. Horizontal line segment Horizontal line segment and horizontal line segments The corresponding voltages are approximately 0.11 V, 0.2 V, 0.38 V and 0.55 V. Therefore, the gains of the amplifiers 111A-111D of the protection circuit 110 (or the amplifiers 231A-231D of the bias detection circuit 230) can be set so that the protection circuit 110 (or the bias detection circuit 230) has four voltage thresholds corresponding to the four temperature ranges: 0.11 V, 0.2 V, 0.38 V and 0.55 V.

[0047] The detailed operation of how the bias voltage detection circuit 230 selects an amplifier in response to temperature changes is described below. The operation of the protection circuit 110 selecting an amplifier is similar to that of the bias voltage detection circuit 230 and will not be repeated here.

[0048] For example, see Figure 4 and Figure 5 , the processor 220 of the power management system 200 detects that the temperature value of the battery 500 is -15°C, and determines that the temperature value of the battery 500 is between -26°C and -17°C. At this time, the processor 220 controls the multiplexer 232 of the bias detection circuit 230 to select the output voltage of the amplifier 231B corresponding to the aforementioned temperature range to output to the comparator 233.

[0049] Next, when the processor 220 detects that the temperature value of the battery 500 rises from -15°C to 5°C, and determines that the temperature value of the battery 500 is between the temperature range of -17°C to 0°C, the processor 220 responds to the temperature change of the battery 500 to control the multiplexer 232 of the bias detection circuit 230 to switch the output voltage of the output amplifier 231B to the output voltage of the amplifier 231C corresponding to the aforementioned temperature range, and output it to the comparator 233.

[0050] Next, when the processor 220 detects that the temperature value of the battery 500 rises from 5°C to 40°C, and determines that the temperature value of the battery 500 is between the temperature range of 0°C to 45°C, the processor 220 responds to the temperature change of the battery 500 to control the multiplexer 232 of the bias detection circuit 230 to switch the output voltage of the output amplifier 231C to the output voltage of the amplifier 231D corresponding to the aforementioned temperature range, and output it to the comparator 233.

[0051] According to the above embodiments, the short circuit protection system 100 and the battery management system 200 provided by the present invention can adaptively select an appropriate voltage threshold for short circuit protection according to the operating temperature. Therefore, the short circuit protection system 100 and the battery management system 200 provided by the present invention can disconnect the current path between the internal battery and the external load in real time regardless of low temperature, normal temperature or high temperature, so as to reduce the damage caused by the short circuit current.

[0052] Although the present invention is disclosed in detail with reference to the embodiments above, the present invention does not exclude other feasible implementations. Therefore, the protection scope of the present invention shall be determined by the appended claims, rather than being limited by the aforementioned embodiments.

[0053] For those skilled in the art, various changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention. Based on the above embodiments, all changes and modifications made to the present invention are also included in the protection scope of the present invention.

[0054]

Explanation of symbols

[0055] 100: Short circuit protection system

[0056] 110: Protection circuit

[0057] 120: Controller

[0058] 700: Load

[0059] 900: Electronic devices

[0060] 910: Switch

[0061] 920: Power

[0062] T1: Transistor

[0063] S: The first terminal of the transistor

[0064] D: The second terminal of the transistor

[0065] G: control terminal of transistor

[0066] 111A~111D:Amplifier

[0067] R1a~R4a, R1b~R4b, R1c~R4c, R1d~R4d, R2, R3: resistor

[0068] OP1~OP5: Operational amplifier

[0069] 112: Multiplexer

[0070] 113: Comparator

[0071] I: Current

[0072] Vref: preset voltage

[0073] 200: Battery Management System

[0074] 210: Switch

[0075] 220: Processor

[0076] 230: Bias detection circuit

[0077] 300: Load

[0078] 500: Battery

[0079] 231A~231D:Amplifier

[0080] 232: Multiplexer

[0081] 233: Comparator

[0082] A: Initial point

[0083] B~D,A'~C': intersection point

[0084] E: upper limit point

[0085] L1: Protection current temperature curve

[0086] L2: Working current temperature curve

[0087] P1~P7:Point

[0088] V DS : The voltage across the switch.

Claims

1. A short circuit protection system, applied to an electronic device, wherein the electronic device has a switch, and the switch is used to connect or disconnect the electrical connection between the electronic device and an external load, characterized in that: The short circuit protection system comprises: A protection circuit, used to detect the voltage across the switch, and comprising a plurality of voltage thresholds corresponding to a plurality of temperature ranges; and A controller is used to obtain the temperature value of the electronic device and set the protection circuit to select a corresponding one of the multiple voltage thresholds according to the temperature value, wherein when the cross-voltage is greater than one of the multiple voltage thresholds, the switch enables the protection circuit to output an interrupt signal to the controller, wherein when the controller receives the interrupt signal, the controller disconnects the switch.

2. The short circuit protection system according to claim 1, characterized in that: When the cross voltage of the switch changes from less than one of the voltage thresholds to greater than one of the voltage thresholds, the protection circuit is used to switch the voltage provided to the controller from a first level to a second level to output the interrupt signal.

3. The short circuit protection system according to claim 1, characterized in that: The protection circuit comprises: A plurality of amplifiers, for amplifying the cross-voltage, wherein the plurality of amplifiers correspond to the plurality of temperature intervals respectively and have different gains; A multiplexer, comprising a plurality of input terminals, wherein the plurality of input terminals are electrically connected to the plurality of amplifiers respectively, wherein the controller is used to control the multiplexer to output an output voltage of one of the plurality of amplifiers according to the temperature value of the electronic device, thereby setting the voltage threshold as the protection circuit; as well as The comparator is electrically connected to the controller and the multiplexer and is used for comparing the output voltage with a preset voltage to determine the voltage level of the interrupt signal.

4. The short circuit protection system according to claim 1, characterized in that: The multiple temperature intervals correspond to a mapping relationship between a protection current temperature curve and an operating current temperature curve of the switch, a point in the protection current temperature curve corresponding to a temperature is greater than a point in the operating current temperature curve corresponding to the temperature, wherein the protection current temperature curve includes an initial point corresponding to a preset temperature value of the battery, wherein horizontal mapping and vertical mapping are sequentially performed between the protection current temperature curve and the operating current temperature curve from the initial point of the protection current temperature curve to obtain multiple horizontal line segments and multiple vertical line segments, the multiple horizontal line segments and the multiple vertical line segments are alternately connected to each other, and the multiple horizontal line segments are the multiple temperature intervals.

5. A battery management system, characterized in that: Include: A switch electrically connected between the load and the battery; A processor, electrically connected to the switch, and used to obtain a temperature value of the battery; as well as A bias voltage detection circuit is electrically connected to the switch and the processor and is used to detect the voltage across the switch, wherein the processor sets the working state of the bias voltage detection circuit according to the position of the temperature value in a plurality of temperature intervals; The bias voltage detection circuit generates an interrupt signal to the processor according to the working state and the cross voltage, and the processor controls the switch according to the interrupt signal. The cross-pressure is associated with the position of the temperature value in the plurality of temperature intervals.

6. The battery management system according to claim 5, characterized in that: The bias detection circuit comprises: A plurality of amplifiers, for amplifying the cross-voltage, wherein the plurality of amplifiers correspond to the plurality of temperature intervals respectively and have different gains; a multiplexer comprising a plurality of input terminals, wherein the plurality of input terminals are electrically connected to the plurality of amplifiers respectively, wherein the processor is used to control the multiplexer to output an output voltage of one of the plurality of amplifiers according to the temperature value of the battery, thereby setting the working state of the bias detection circuit; as well as The comparator is electrically connected to the processor and the multiplexer and is used to compare the output voltage with a preset voltage to determine the voltage level of the interrupt signal.

7. The battery management system according to claim 6, characterized in that: The switch includes a transistor including a drain terminal, a source terminal and a gate terminal. The plurality of amplifiers are respectively electrically connected to the drain terminal and the source terminal of the transistor. The gate terminal of the transistor is electrically connected to the processor.

8. The battery management system according to claim 5, characterized in that: When the output voltage is greater than the preset voltage, the processor turns off the switch, and when the output voltage is less than or equal to the preset voltage, the processor turns on the switch.

9. The battery management system according to claim 6, characterized in that: The multiple temperature intervals correspond to a mapping relationship between a protection current temperature curve and an operating current temperature curve of the switch, a point in the protection current temperature curve corresponding to a temperature is greater than a point in the operating current temperature curve corresponding to the temperature, wherein the protection current temperature curve includes an initial point corresponding to a preset temperature value of the battery, wherein horizontal mapping and vertical mapping are sequentially performed between the protection current temperature curve and the operating current temperature curve from the initial point of the protection current temperature curve to obtain multiple horizontal line segments and multiple vertical line segments, the multiple horizontal line segments and the multiple vertical line segments are alternately connected to each other, and the multiple horizontal line segments are the multiple temperature intervals.

10. The battery management system according to claim 9, characterized in that: The number of the plurality of temperature intervals is proportional to the number of the plurality of amplifiers.

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