A control system and control method for an overcurrent protection circuit and related components

Abstract

The present invention discloses a control system and a control method for an overcurrent protection circuit and related components. In this solution, by designing a multi-stage amplification circuit, the sampling voltage output by the sampling circuit is subjected to multi-stage amplification processing to ensure the sensitivity of the overcurrent circuit. In addition, by controlling the comparison circuit to determine whether the amplified sampling voltage is greater than a preset threshold after the multi-stage amplification circuit starts to amplify and after a preset time, the working time of the comparison circuit is reduced, and accordingly the power consumption of the comparison circuit is reduced. It can be seen that although the present application sets a multi-stage amplification circuit to improve the sensitivity of the overcurrent protection circuit, it can also reduce the power consumption of the overcurrent protection circuit by reducing the working time of the comparison circuit, so that the overcurrent protection circuit has both the characteristics of high sensitivity and low power consumption.

Description

Technical Field

[0001] The present invention relates to the field of integrated circuits, and particularly to a control system and a control method for an overcurrent protection circuit and related components. Background Art

[0002] With the gradual popularization of electric vehicles, various power batteries are used more and more widely, and the monitoring of battery current is particularly important because it determines people's personal and property safety. As an important part of the battery management system, the overcurrent protection circuit constantly detects the current status of the battery and can detect whether the battery current is greater than a threshold value to avoid battery failure due to excessive current.

[0003] However, in the prior art, in order to improve the sensitivity of the overcurrent protection circuit when detecting the battery current, a multi-stage amplifier circuit needs to be added to achieve this, but this method will lead to an increase in energy consumption. Based on this, how to avoid the increase in power consumption while improving the sensitivity is an urgent problem for those skilled in the art. Summary of the Invention

[0004] The purpose of the present invention is to provide a control system and a control method for an overcurrent protection circuit and related components, in which although a multi-stage amplifier circuit is set to improve the sensitivity of the overcurrent protection circuit, the power consumption of the overcurrent protection circuit can be reduced by reducing the working time of the comparison circuit, so that the overcurrent protection circuit has both high sensitivity and low power consumption.

[0005] To solve the above technical problems, the present invention provides a control system for an overcurrent protection circuit. The overcurrent protection circuit includes a sampling circuit, a multi-stage amplifier circuit, and a comparison circuit connected in sequence; the input end of the sampling circuit is connected to the battery; the system includes:

[0006] A parameter setting unit for determining a preset time based on the parameters of the multi-stage amplifier circuit and the gain of the multi-stage amplifier circuit;

[0007] A first control unit for controlling the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time controlling the output of the multi-stage amplifier circuit to be reset;

[0008] A second control unit for controlling the multi-stage amplifier circuit to perform amplification processing on the sampling voltage after a preset sampling time to output the amplified sampling voltage;

[0009] A third control unit for controlling the comparison circuit to determine whether the amplified sampling voltage is greater than a preset threshold value after the preset time since the multi-stage amplifier circuit starts to perform amplification processing, so as to determine whether the output current or input current of the battery is greater than a preset current threshold value.

[0010] To solve the above technical problems, the present invention provides a control method for an overcurrent protection circuit. Based on the control system of the overcurrent protection circuit described above, the overcurrent protection circuit includes a sampling circuit, a multi-stage amplification circuit, and a comparison circuit connected in sequence; the input end of the sampling circuit is connected to the battery; the method includes:

[0011] Determine a preset time based on the parameters of the multi-stage amplification circuit and the gain of the multi-stage amplification circuit;

[0012] Control the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time control the output of the multi-stage amplification circuit to be reset;

[0013] After a preset sampling time, control the multi-stage amplification circuit to amplify the sampling voltage to output the amplified sampling voltage;

[0014] Control the comparison circuit to determine whether the amplified sampling voltage is greater than a preset threshold when the preset time has elapsed since the multi-stage amplification circuit started the amplification process, so as to determine whether the output current or input current of the battery is greater than a preset current threshold.

[0015] Preferably, the overcurrent protection circuit further includes a reset switch; the negative output end of the multi-stage amplification circuit is connected to the first end of the reset switch and the positive input end of the comparison circuit, and the positive output end is connected to the second end of the reset switch and the negative input end of the comparison circuit;

[0016] Controlling the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time controlling the output of the multi-stage amplification circuit to be reset, includes:

[0017] Control the reset switch to close to reset the output of the multi-stage amplification circuit;

[0018] After a preset lead time, control the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage.

[0019] Preferably, after a preset sampling time, controlling the multi-stage amplification circuit to amplify the sampling voltage to output the amplified sampling voltage includes:

[0020] After the preset sampling time, control the sampling circuit to stop outputting;

[0021] After controlling the sampling circuit to stop output and after a preset hysteresis time, control the reset switch to disconnect, so that the multi-stage amplifier circuit amplifies the sampling voltage to output the amplified sampling voltage.

[0022] Preferably, control the sampling circuit to sample and convert the output current or input current of the battery into a sampling voltage, and at the same time control the output reset of the multi-stage amplifier circuit; after a preset sampling time, control the multi-stage amplifier circuit to amplify the sampling voltage to output the amplified sampling voltage; control the comparison circuit to judge whether the amplified sampling voltage is greater than a preset threshold after the preset time since the multi-stage amplifier circuit starts to perform amplification processing, so as to judge whether the output current or input current of the battery is greater than a preset current threshold, including:

[0023] S201: Control the reset switch to close;

[0024] S202: After the preset lead time, control the sampling circuit to sample and convert the output current or input current of the battery into a sampling voltage;

[0025] S203: After the preset sampling time, control the sampling circuit to stop output;

[0026] S204: After the preset hysteresis time, control the reset switch to disconnect, so that the multi-stage amplifier circuit amplifies the sampling voltage to output the amplified sampling voltage;

[0027] S205: After the preset time, control the comparison circuit to judge whether the amplified sampling voltage is greater than a preset threshold, so as to judge whether the output current or input current of the battery is greater than a preset current threshold;

[0028] S206: After a preset comparison time, return to step S201.

[0029] Preferably, the multi-stage amplifier circuit includes a first amplifier, a second amplifier, a first amplification switch, a second amplification switch, and a third amplification switch; the positive input terminal of the first amplifier is connected to the first output terminal of the sampling circuit, and the negative input terminal is connected to the second output terminal of the sampling circuit; the positive input terminal of the second amplifier is connected to the negative output terminal of the first amplifier, the negative input terminal is connected to the positive output terminal of the first amplifier, the negative output terminal is the negative output terminal of the multi-stage amplifier circuit, and the positive output terminal is the positive output terminal of the multi-stage amplifier circuit; the first end of the first amplification switch is connected to the positive input terminal of the first amplifier, and the second end is connected to the negative output terminal of the first amplifier; the first end of the second amplification switch is connected to the negative input terminal of the first amplifier, and the second end is connected to the positive output terminal of the first amplifier; the first end of the third amplification switch is connected to the negative output terminal of the first amplifier, and the second end is connected to the positive output terminal of the first amplifier;

[0030] After controlling the reset switch to close, it further includes:

[0031] When the sampling circuit samples the output current or input current of the battery and converts it into a sampling voltage, control the first amplification switch and the second amplification switch to close;

[0032] When the sampling circuit stops outputting, control the first amplification switch and the second amplification switch to open, and control the third amplification switch to close;

[0033] When the reset switch is open, control the third amplification switch to open.

[0034] Preferably, the sampling circuit includes a sampling resistor, a switching switch, a control switch, and a sampling capacitor connected in sequence;

[0035] Controlling the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time controlling the output reset of the multi-stage amplifier circuit, includes:

[0036] Controlling the switching switch at a preset frequency so that the sampling circuit samples the output current or input current of the battery at the preset frequency, and at the same time controlling the output reset of the multi-stage amplifier circuit;

[0037] Controlling the control switch so that the sampling capacitor converts the input current or the output current sampled by the sampling capacitor into the sampling voltage.

[0038] Preferably, the comparison circuit includes a comparator and a latch;

[0039] Controlling the comparison circuit to determine whether the sampled voltage after amplification processing is greater than a preset threshold when the preset time has elapsed since the multi-stage amplification circuit started the amplification process, so as to determine whether the output current or input current of the battery is greater than a preset current threshold, includes:

[0040] Controlling the comparator to determine whether the sampled voltage after amplification processing is greater than a preset threshold when the preset time has elapsed since the multi-stage amplification circuit started the amplification process, and when it is greater, making the latch output a high level, and when it is not greater, making the latch output a low level;

[0041] When the latch outputs the high level, it is determined that the output current or input current of the battery is greater than the preset current threshold;

[0042] When the latch outputs the low level, it is determined that the output current or input current of the battery is not greater than the preset current threshold.

[0043] To solve the above technical problems, the present invention provides a control device for an overcurrent protection circuit, including:

[0044] A memory for storing a computer program;

[0045] A processor for implementing the steps of the control method of the overcurrent protection circuit as described above when executing the computer program.

[0046] To solve the above technical problems, the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the control method of the overcurrent protection circuit as described above are implemented.

[0047] This application provides a control system and control method for an overcurrent protection circuit and related components. In this solution, by designing a multi-stage amplification circuit, the sampled voltage output by the sampling circuit is subjected to multi-stage amplification processing to ensure the sensitivity of the overcurrent circuit. In addition, by controlling the comparison circuit to determine whether the amplified sampled voltage is greater than a preset threshold after the multi-stage amplification circuit starts to amplify and after a preset time, the working time of the comparison circuit is reduced, and accordingly the power consumption of the comparison circuit is reduced. It can be seen that although this application sets up a multi-stage amplification circuit to improve the sensitivity of the overcurrent protection circuit, it can also reduce the power consumption of the overcurrent protection circuit by reducing the working time of the comparison circuit, making the overcurrent protection circuit have both the characteristics of high sensitivity and low power consumption. Description of the Drawings

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required in the prior art and the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0049] Figure 1 FIG. Figure 1 is a schematic structural diagram of a control system for an overcurrent protection circuit provided by the present invention;

[0050] Figure 2 FIG. Figure 2 is a schematic structural diagram of an overcurrent protection circuit in the prior art;

[0051] Figure 3 FIG. Figure 3 is a schematic flowchart of a control method for an overcurrent protection circuit provided by the present invention;

[0052] Figure 4 FIG. Figure 4 is a specific schematic structural diagram of an overcurrent protection circuit provided by the present invention;

[0053] Figure 5 FIG. Figure 5 is a schematic structural diagram of a first amplifier provided by the present invention;

[0054] Figure 6 FIG. Figure 6 is a schematic structural diagram of a second amplifier provided by the present invention;

[0055] Figure 7 FIG. Figure 7 is a timing diagram provided by the present invention;

[0056] Figure 8 FIG. Figure 8 is a schematic structural diagram of a comparator provided by the present invention;

[0057] Figure 9 FIG. Figure 9 is a schematic structural diagram of a control device for an overcurrent protection circuit provided by the present invention. Detailed Embodiments

[0058] The core of the present invention is to provide a control system and a control method for an overcurrent protection circuit and related components. Although a multi-stage amplifier circuit is set to improve the sensitivity of the overcurrent protection circuit, the working time of the comparison circuit can be reduced to reduce the power consumption of the overcurrent protection circuit, so that the overcurrent protection circuit has both high sensitivity and low power consumption.

[0059] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0060] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a control system for an overcurrent protection circuit provided by the present invention. The overcurrent protection circuit includes a sampling circuit 21, a multi-stage amplifier circuit 22, and a comparison circuit 23 that are connected in sequence. The input end of the sampling circuit 21 is connected to a battery. Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of an overcurrent protection circuit in the prior art. The system includes:

[0061] A parameter setting unit 11, configured to determine a preset time based on the parameters of the multi-stage amplifier circuit 22 and the gain of the multi-stage amplifier circuit 22;

[0062] In this embodiment, considering that in the prior art, in order to increase the amplification factor of the output current or input current of the battery, it is usually achieved by setting a multi-stage amplifier circuit 22. Moreover, while the multi-stage amplifier circuit 22 amplifies the input current or output current of the battery, the comparison circuit 23 also compares whether the amplified input current or output current is greater than a preset threshold. Therefore, the overcurrent protection circuit in the prior art can only increase the amplification factor to improve the accuracy, but cannot reduce the power consumption at the same time. And if you want to reduce the power consumption of the overcurrent protection circuit, you cannot set a multi-stage amplifier circuit 22 to improve the accuracy.

[0063] To solve the above technical problems, in the present application, a multi-stage amplifier circuit 22 is first set up to ensure the accuracy of the overcurrent protection circuit. During the control process, first, the parameter setting unit 11 determines a preset time based on the parameters of the multi-stage amplifier circuit 22 and the gain of the multi-stage amplifier circuit 22. Here, the preset time is the amplification time of the multi-stage amplifier circuit 22, and the gain is the amplification factor of the multi-stage amplifier circuit 22, so that the comparison circuit 23 can compare the sampled voltage output after the amplification process by the multi-stage amplifier circuit 22 with the preset threshold, so as to accurately output a comparison result even when the sampled voltage is small and improve the sensitivity. In addition, by setting the preset time during the amplification process by the multi-stage amplifier circuit 22, it is ensured that the voltage output by the multi-stage amplifier circuit 22 when the comparison circuit 23 is working is already the sampled voltage after the amplification gain, reducing the working time of the comparison circuit 23 and correspondingly reducing the power consumption of the comparison circuit 23.

[0064] The first control unit 12 is configured to control the multi-stage amplifier circuit 22 to amplify the sampled voltage when the sampling circuit 21 samples the output current or input current of the battery and converts it into a sampled voltage, and control the output reset of the multi-stage amplifier circuit 22.

[0065] In this embodiment, when determining whether the output current (discharge current) or input current (charging current) of the battery exceeds the threshold, the first control unit 12 first samples the output current or input current of the battery, converts the output current or input current of the battery into a sampled voltage and then makes a comparison. At this time, the output reset of the multi-stage amplifier circuit 22 is controlled to reduce the loss of the multi-stage amplifier circuit 22.

[0066] The second control unit 13 is configured to control the multi-stage amplifier circuit 22 to perform amplification processing after a preset sampling time, so as to output the sampled voltage after amplification processing.

[0067] After a preset sampling time, the second control unit 13 controls the multi-stage amplifier circuit 22 to perform amplification processing on the sampled voltage, so as to output the sampled voltage after amplification processing. The amplification factor when the multi-stage amplifier circuit 22 performs amplification processing on the sampled voltage is its gain, so as to ensure the sensitivity of the overcurrent protection circuit.

[0068] The third control unit 14 is configured to control the comparison circuit 23 to determine whether the sampled voltage after amplification processing is greater than a preset threshold after a preset time since the multi-stage amplifier circuit 22 starts to perform amplification processing, so as to determine whether the output current or input current of the battery is greater than a preset current threshold.

[0069] After the multi-stage amplifier circuit 22 starts to perform amplification processing, after a preset time, the comparison circuit 23 starts to make a judgment based on whether the sampled voltage after amplification processing is greater than a preset threshold. That is, after a preset sampling time and then after a preset time, the comparator starts to work. At this time, the output of the multi-stage amplifier circuit 22 has reached the sampled voltage with the gain as the amplification factor, and the comparison circuit 23 can directly make a comparison according to the sampled voltage after amplification processing, which can not only determine whether the output current or input current of the battery is too large, but also reduce the power consumption of the comparison circuit 23.

[0070] In summary, although this application sets a multi-stage amplifier circuit 22 to improve the sensitivity of the overcurrent protection circuit, it can also reduce the power consumption of the overcurrent protection circuit by reducing the working time of the comparison circuit 23, so that the overcurrent protection circuit has both the characteristics of high sensitivity and low power consumption.

[0071] Please refer to Figure 3 , Figure 3Schematic flowchart of a control method for an overcurrent protection circuit provided by the present invention. The overcurrent protection circuit includes a sampling circuit 21, a multi-stage amplification circuit 22, and a comparison circuit 23 connected in sequence. The input end of the sampling circuit 21 is connected to the battery. The method includes:

[0072] S101: Determine a preset time based on the parameters of the multi-stage amplification circuit 22 and the gain of the multi-stage amplification circuit 22;

[0073] S102: Control the sampling circuit 21 to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time control the output of the multi-stage amplification circuit 22 to be reset;

[0074] S103: After a preset sampling time, control the multi-stage amplification circuit 22 to amplify the sampling voltage to output the amplified sampling voltage;

[0075] S104: Control the comparison circuit 23 to determine whether the amplified sampling voltage is greater than a preset threshold at a preset time after the multi-stage amplification circuit 22 starts the amplification process, so as to determine whether the output current or input current of the battery is greater than a preset current threshold.

[0076] For the introduction of a control method for an overcurrent protection circuit provided by the present invention, please refer to the above system embodiment, and the present invention will not be elaborated here.

[0077] Based on the above embodiments:

[0078] Please refer to Figure 4 , Figure 4 which is a specific structural schematic diagram of an overcurrent protection circuit provided by the present invention.

[0079] As a preferred embodiment, the overcurrent protection circuit further includes a reset switch S4. The negative output terminal of the multi-stage amplification circuit 22 is connected to the first terminal of the reset switch S4 and the positive input terminal of the comparison circuit 23, and the positive output terminal is connected to the second terminal of the reset switch S4 and the negative input terminal of the comparison circuit 23;

[0080] Controlling the sampling circuit 21 to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time controlling the output of the multi-stage amplification circuit 22 to be reset, includes:

[0081] Control the reset switch S4 to close to reset the output of the multi-stage amplification circuit 22;

[0082] After a preset lead time, control the sampling circuit 21 to sample the output current or input current of the battery and convert it into a sampling voltage.

[0083] A reset switch S4 is provided between the positive output terminal and the negative output terminal of the multi-stage amplifier circuit 22 in this embodiment. By closing the reset switch S4, the output of the multi-stage amplifier circuit 22 is reset, that is, when the output terminals of the multi-stage amplifier circuit 22 are short-circuited, the output of the multi-stage amplifier circuit 22 is reset.

[0084] It should be noted that in this embodiment, before controlling the sampling circuit 21 to sample the output current or input current of the battery, the reset switch S4 is first controlled to close, so as to ensure that the sampling circuit 21 samples the input current or output current of the battery on the premise that the output of the multi-stage amplifier circuit 22 is reset.

[0085] As a preferred embodiment, after a preset sampling time, the multi-stage amplifier circuit 22 is controlled to amplify the sampling voltage to output the amplified sampling voltage, including:

[0086] After a preset sampling time, the sampling circuit 21 is controlled to stop outputting;

[0087] After controlling the sampling circuit 21 to stop outputting and after a preset lag time, the reset switch S4 is controlled to disconnect, so that the multi-stage amplifier circuit 22 amplifies the sampling voltage to output the amplified sampling voltage.

[0088] In this embodiment, after a preset sampling time, the sampling circuit 21 is controlled to stop outputting, that is, the sampling is completed. After a preset lag time, the reset switch S4 is controlled to disconnect, so that the multi-stage amplifier circuit 22 starts to amplify the sampling voltage. Due to the preset lag time, it is ensured that the multi-stage amplifier circuit 22 is in the output reset state when the sampling circuit 21 samples the output current or input current of the battery.

[0089] As a preferred embodiment, the sampling circuit 21 is controlled to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time, the output of the multi-stage amplifier circuit 22 is reset; after a preset sampling time, the multi-stage amplifier circuit 22 is controlled to amplify the sampling voltage to output the amplified sampling voltage; the comparison circuit 23 is controlled to judge whether the amplified sampling voltage is greater than a preset threshold after a preset time since the multi-stage amplifier circuit 22 starts to perform the amplification process, so as to judge whether the output current or input current of the battery is greater than a preset current threshold, including:

[0090] S201: Control the reset switch S4 to close;

[0091] S202: After a preset lead time, control the sampling circuit 21 to sample the output current or input current of the battery and convert it into a sampling voltage;

[0092] S203: After a preset sampling time, control the sampling circuit 21 to stop outputting;

[0093] S204: After a preset lag time, control the reset switch S4 to disconnect, so that the multi-stage amplification circuit 22 amplifies the sampled voltage to output the amplified sampled voltage;

[0094] S205: After a preset time, control the comparison circuit 23 to determine whether the amplified sampled voltage is greater than a preset threshold, so as to determine whether the output current or input current of the battery is greater than a preset current threshold;

[0095] S206: After a preset comparison time, return to step S201.

[0096] In this embodiment, an example of the sequence relationship when the sampling circuit 21, the multi-stage amplification circuit 22, and the comparison circuit 23 work is given. Specifically, before controlling the sampling circuit 21 to sample, first control the reset switch S4 to close to ensure the output reset of the amplification circuit at this time. Subsequently, after a preset lead time, control the sampling circuit 21 to sample the output current or input current of the battery. After a preset sampling time, the sampling circuit 21 stops sampling. After a preset lag time, the reset switch S4 disconnects, and the multi-stage amplification circuit 22 starts to amplify the sampled voltage, and the amplification multiple of the amplified sampled voltage is the gain to ensure the sensitivity of the overcurrent protection circuit. After the multi-stage amplification circuit 22 works for a preset time, control the comparison circuit 23 to start working, that is, determine whether the amplified sampled voltage is greater than a preset threshold. If it is greater, it can be determined that the output current or input current of the battery is greater than the preset current threshold, and if it is not greater, it can be determined that the output current or input current of the battery is not greater than the preset current threshold.

[0097] After executing the above steps once, return to step S201 to enter a loop to continuously monitor the output current or input current of the battery, so as to be able to process it in a timely manner when the output current or input current of the battery is too large and avoid more serious situations.

[0098] As a preferred embodiment, the multi-stage amplification circuit 22 includes a first amplifier AMP1, a second amplifier AMP2, a first amplification switch S15, a second amplification switch S16, and a third amplification switch S3; the positive input terminal of the first amplifier AMP1 is connected to the first output terminal of the sampling circuit 21, and the negative input terminal is connected to the second output terminal of the sampling circuit 21; the positive input terminal of the second amplifier AMP2 is connected to the negative output terminal of the first amplifier AMP1, the negative input terminal is connected to the positive output terminal of the first amplifier AMP1, the negative output terminal is the negative output terminal of the multi-stage amplification circuit 22, and the positive output terminal is the positive output terminal of the multi-stage amplification circuit 22; the first end of the first amplification switch S15 is connected to the positive input terminal of the first amplifier AMP1, and the second end is connected to the negative output terminal of the first amplifier AMP1; the first end of the second amplification switch S16 is connected to the negative input terminal of the first amplifier AMP1, and the second end is connected to the positive output terminal of the first amplifier AMP1; the first end of the third amplification switch S3 is connected to the negative output terminal of the first amplifier AMP1, and the second end is connected to the positive output terminal of the first amplifier AMP1;

[0099] After controlling the reset switch S4 to close, it further includes:

[0100] When the sampling circuit 21 samples the output current or input current of the battery and converts it into a sampling voltage, control the first amplification switch S15 and the second amplification switch S16 to close;

[0101] When the sampling circuit 21 stops outputting, control the first amplification switch S15 and the second amplification switch S16 to open, and control the third amplification switch S3 to close;

[0102] When the reset switch S4 is open, control the third amplification switch S3 to open.

[0103] In this embodiment, the first amplification switch S15, the second amplification switch S16, and the reset switch S4 in the multi-stage amplification circuit 22 are closed when the sampling circuit 21 samples the output current or input current of the battery. At this time, the first amplifier AMP1 is in the unity-gain buffer mode, that is, the first amplifier AMP1 follows the sampling voltage output by the sampling circuit 21. While the sampling circuit 21 stops outputting, the first amplification switch S15 and the second amplification switch S16 are open, the third amplification switch S3 is closed, and the closing time of the third switch is a preset lag time. After the preset lag time, the reset switch S4 is open, and at the same time the third amplification switch S3 is open.

[0104] When the third amplification switch S3 is closed, it is ensured that the first amplifier AMP1 fully follows the sampling voltage before amplifying the sampling voltage. When the third amplification switch S3 is open and the reset switch S4 is open, it enters the amplification stage, and the sampling voltage is amplified by the first amplifier AMP1 and the second amplifier AMP2.

[0105] The first amplifier AMP1 can be but is not limited to a fully differential amplifier with common-mode feedback. The circuit diagram is as shown in FIG. Figure 5 and Figure 6 , Figure 5 A schematic diagram of the structure of a first amplifier provided by the present invention, Figure 6 This is a schematic structural diagram of a second amplifier provided by the present invention.

[0106] Figure 5 Among them, MP1, MP2, MN1, MN2 and MP10 constitute the first stage of the first amplifier AMP1, and MP9, MP11, MN3, MN4 constitute the second stage of the first amplifier AMP1. These two stages make the first amplifier AMP1 have a larger DC gain. R2, R3, C30, C31 constitute a compensation circuit from the first stage to the second stage to prevent the first amplifier AMP1 from oscillating when working in a unit gain buffer state. MP3, MP4, MP5, MP6, MP7, MP8, MN5, MN6 constitute the common mode feedback loop of the first amplifier AMP1, detect the common mode voltage of VO1+ and VO1-, and make the output common mode voltage of VO1+ and VO1- equal to VCM. VCM is the reference voltage, that is, the virtual ground. VBP is the control signal of MP9, MP10, MP11, MP7 and MP8.

[0107] In the amplification stage, the first amplifier AMP1 works in an open loop state. Assuming that the sampling circuit 21 collects the input current of the battery at a certain moment, according to Kirchhoff's current law, it can be obtained that Figure 4 Midpoint V X and V Y The voltages are:

[0108] ;

[0109] ;

[0110] In the sampling stage, since the first amplifier AMP1 has a large low-frequency gain, V X Approximately equal to V Y .

[0111] Therefore, the preset threshold is:

[0112] ;

[0113] The preset threshold is designed to be adjustable to meet the application of different current limiting levels. The present application can provide two solutions to change the threshold, one is to fix the value of C21 / C11 and design VREF to be variable; the other is to fix the VREF value and change C21 / C11.

[0114] In the amplification stage, the first amplifier AMP1 converts VX and V Y The difference between them is amplified, and the output voltage difference between VO1+ and VO1- depends on the amplification stage duration, which is also the preset time and V X -V Y 。

[0115] The circuit of the second amplifier AMP2 is as Figure 6 , the second amplifier AMP2 adopts a two-stage fully differential structure. The first stage of the second amplifier AMP2 is composed of MP21, MP22, MP23, MN11 and MN12, and the second stage of the second amplifier AMP2 is composed of MP24, MP25, MN13 and MN14, which further improves the DC gain in the amplification stage. VBP is the control signal of MP23, MP24 and MP25. The total DC gain of the first amplifier AMP1 and the second amplifier AMP2 in the amplification stage is the product of the two, which is the key for the present invention to achieve high sensitivity.

[0116] As a preferred embodiment, the sampling circuit 21 includes a sampling resistor R1, a switching switch, a control switch and a sampling capacitor connected in sequence;

[0117] Control the sampling circuit 21 to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time control the output reset of the multi-stage amplification circuit 22, including:

[0118] Control the switching switch at a preset frequency so that the sampling circuit 21 samples the output current or input current of the battery at a preset frequency, and at the same time control the output reset of the multi-stage amplification circuit 22;

[0119] Control the control switch so that the sampling capacitor converts the input current or output current sampled by the sampling capacitor into a sampling voltage.

[0120] In this embodiment, the sampling resistor R1 in the sampling circuit 21 can convert the output current or input current of the battery into a sampling voltage, which is convenient for judging whether the output current or input current of the battery is greater than the preset current threshold. In addition, by controlling the switching switch at a preset frequency, the sampling circuit 21 can sample the output current or input current of the battery at a preset frequency, so that it can be detected in time when the battery changes from the discharge state to the charging state, or from the charging state to the discharge state, and corresponding overcurrent judgment and protection can be carried out.

[0121] For example, as Figure 4 shown, Figure 4The control switch includes a first sampling control switch S11, a second sampling control switch S12, a third sampling control switch S13, a fourth sampling control switch S14, a first amplification control switch S12, a second amplification control switch S22, a third amplification control switch S23, and a fourth amplification control switch S24. The first sampling control switch S11, the second sampling control switch S12, the third sampling control switch S13, and the fourth sampling control switch S14 are simultaneously turned on or off. The first amplification control switch S12, the second amplification control switch S22, the third amplification control switch S23, and the fourth amplification control switch S24 are simultaneously turned on or off. The first sampling control switch S11 and the first amplification control switch S12 are not simultaneously turned on. When the first sampling control switch S11, the second sampling control switch S12, the third sampling control switch S13, and the fourth sampling control switch S14 are closed, the sampling circuit 21 samples the input current or output current of the battery. When the first amplification control switch S12, the second amplification control switch S22 are closed, and the third amplification control switch S23 and the fourth amplification control switch S24 are closed, the multi-stage amplification circuit 22 amplifies the sampled voltage.

[0122] The switching switch includes a first input switching switch SEL11, a second input switching switch SEL12, a first output switching switch SEL21, and a second output switching switch SEL22. Among them, the first input switching switch SEL11 and the second input switching switch SEL12 are simultaneously turned on or off. The first output switching switch SEL21 and the second output switching switch SEL22 are simultaneously turned on or off. The first input switching switch SEL11 and the first output switching switch SEL21 are not simultaneously turned on. When the first input switching switch SEL11, the second input switching switch SEL12 are closed, the input current or output current of the battery is collected by charging the sampling capacitor. When the first output switching switch SEL21 and the second output switching switch SEL22 are closed, the first input switching switch S11 and the first output switching switch SEL21S12 are sequentially turned on at a preset frequency to collect the input current or output current of the battery at the preset frequency.

[0123] The sampling resistor R1 is used to detect the current Idet flowing through itself externally and convert it into the voltage difference VIN - VIP across its two ends, that is, the sampling voltage. The overcurrent protection circuit in this application can be divided into three working stages: the sampling stage, the amplification stage, and the comparison stage. The sampling capacitors C11 = C12, C21 = C22, and the gating period of the switching switch is much longer than the gating period of the control switch.

[0124] Please refer to Figure 7 , Figure 7 which is a timing diagram provided by the present invention. It should be noted that in this embodiment Figure 4Each switch in it is turned on when at high level.

[0125] Sampling stage: At this time, the first sampling control switch SEL11, the second sampling control switch SEL12 and the third sampling control switch are closed, that is, Figure 7 the level of S11 in it is at high level, the sampling capacitors C11 and C12 sample VIN and VIP across the sampling resistor R1 respectively, the sampling capacitors C21 and C22 sample GND and the reference voltage VREF respectively, at this time the first amplifier AMP1 is in the unity-gain buffer mode, and the output of the second amplifier AMP2 is reset;

[0126] Amplification stage: At this time, the first amplification control switch, the second amplification control switch and the third amplification control switch are closed, that is, Figure 7 for the part of the level of S11 in it, the signals sampled in the sampling stage are amplified by the first amplifier AMP1 and the second amplifier AMP2 and reach the input end of the comparator.

[0127] As a preferred embodiment, the comparison circuit 23 includes a comparator and a latch;

[0128] Controlling the comparison circuit 23 to judge whether the sampled voltage after the amplification process is greater than a preset threshold when a preset time has elapsed since the multi-stage amplification circuit 22 starts the amplification process, so as to judge whether the output current or input current of the battery is greater than a preset current threshold, includes:

[0129] Controlling the comparator to judge whether the sampled voltage after the amplification process is greater than a preset threshold when a preset time has elapsed since the multi-stage amplification circuit 22 starts the amplification process, and when it is greater, making the latch output a high level, and when it is not greater, making the latch output a low level;

[0130] When the latch outputs a high level, it is determined that the output current or input current of the battery is greater than the preset current threshold;

[0131] When the latch outputs a low level, it is determined that the output current or input current of the battery is not greater than the preset current threshold.

[0132] The comparison circuit 23 in this embodiment includes a comparator and a latch. Among them, the comparator judges whether the sampled voltage after the amplification process is greater than a preset threshold, and the latch latches and outputs the high level or low level output by the comparator.

[0133] It should be noted that the comparator and the latch in this application do not work when the multi-stage amplifier circuit 22 amplifies the sampling voltage, for example, they are in a sleep state. When a preset time has passed and the voltage output by the multi-stage amplifier circuit 22 is already the sampled voltage amplified by the gain, the judgment is made at this time, reducing the power consumption of the comparator and the latch. By cooperating with the multi-stage amplifier circuit 22, the high sensitivity and low power consumption of the over-current protection circuit are achieved.

[0134] Please refer to Figure 8 , Figure 8 which is a schematic structural diagram of a comparator provided by the present invention.

[0135] The comparator includes MP31, MP32, MP33, MP34, MP35, MP36, MP37, MP38, MP39, MP40, MN31, MN32, MN33, MN34, MN35, MN36, MN37, and MN38. The comparison stage occurs at the last moment of the amplification stage. When COMP_EN is at a low level, the comparator is in a reset state, that is, no comparison is performed, and both VO3+ and VO3- output high levels. When COMP_EN is at a high level, if V3+ > V3-, the comparator outputs VO3+ as high and VO3- as low. At this time, the latch at the subsequent stage outputs high, indicating that the output current or input current of the detected battery exceeds the preset current threshold; if V3+ < V3-, the comparator outputs VO3+ as low and VO3- as high. At this time, the output of the latch is low, indicating that the output current or input current of the battery does not exceed the limit.

[0136] The enable control signal COMP_EN of the comparator controls the comparator to perform comparison at the last moment of the amplification stage, that is, after the multi-stage amplifier circuit 22 has amplified for a preset time. Since both the first amplifier AMP1 and the second amplifier AMP2 use relatively small bias currents, this means that their outputs require a relatively long time to establish. Selecting to perform comparison at the end of the amplification stage can make the positive and negative output differences of the first amplifier AMP1 increase as much as possible during the amplification stage. Furthermore, the positive and negative output differences of the second amplifier AMP2 will also be as large as possible, so as to reduce the requirements for the comparator and improve the sensitivity. Since the comparator is a dynamic latch comparator, almost no current is consumed during reset, and the power consumption is low. Figure 8 V3- and V3+ in

[0137] It should also be noted that the latch in this application is an RS latch, but this is not limited.

[0138] Please refer to Figure 9 , Figure 9 which is a schematic structural diagram of a control device of an over-current protection circuit provided by the present invention, including:

[0139] A memory 91 for storing a computer program;

[0140] A processor 92 for implementing the steps of the control method of the overcurrent protection circuit as described above when executing the computer program.

[0141] For the introduction of a control device of an overcurrent protection circuit provided by the present invention, please refer to the above method embodiments, and the present invention will not be elaborated herein.

[0142] A computer program is stored on a computer-readable storage medium in the present invention, and when the computer program is executed by the processor 92, the steps of the control method of the overcurrent protection circuit as described above are implemented.

[0143] For the introduction of the computer-readable storage medium provided by the present invention, please refer to the above method embodiments, and the present invention will not be elaborated herein.

[0144] It should also be noted that in this specification, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0145] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for an overcurrent protection circuit, based on a control system of the overcurrent protection circuit. The overcurrent protection circuit includes a sampling circuit, a multi-stage amplification circuit, and a comparison circuit connected in sequence; The input end of the sampling circuit is connected to the battery; characterized in that, The method includes: Determine a preset time based on the parameters of the multi-stage amplification circuit and the gain of the multi-stage amplification circuit; Control the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time control the output of the multi-stage amplification circuit to be reset; After a preset sampling time, control the multi-stage amplification circuit to amplify the sampling voltage to output the amplified sampling voltage; Control the comparison circuit to determine whether the amplified sampling voltage is greater than a preset threshold when the preset time has passed since the multi-stage amplification circuit started the amplification process, so as to determine whether the output current or input current of the battery is greater than a preset current threshold; The overcurrent protection circuit further includes a reset switch; the negative output end of the multi-stage amplification circuit is connected to the first end of the reset switch and the positive input end of the comparison circuit, and the positive output end is connected to the second end of the reset switch and the negative input end of the comparison circuit; Control the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time control the output of the multi-stage amplification circuit to be reset, including: Control the reset switch to close to reset the output of the multi-stage amplification circuit; After a preset lead time, control the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage.

2. The control method of the overcurrent protection circuit according to claim 1, characterized in that After a preset sampling time, control the multi-stage amplification circuit to amplify the sampling voltage to output the amplified sampling voltage, including: After the preset sampling time, control the sampling circuit to stop outputting; After controlling the sampling circuit to stop outputting and after a preset lag time, control the reset switch to open so that the multi-stage amplification circuit amplifies the sampling voltage to output the amplified sampling voltage.

3. The control method of the overcurrent protection circuit according to claim 2, characterized in that, Control the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage, and at the same time control the output of the multi-stage amplification circuit to be reset; after a preset sampling time, control the multi-stage amplification circuit to amplify the sampling voltage to output the amplified sampling voltage; control the comparison circuit to determine whether the amplified sampling voltage is greater than a preset threshold when the preset time has passed since the multi-stage amplification circuit started the amplification process, so as to determine whether the output current or input current of the battery is greater than a preset current threshold, including: S201: Control the reset switch to close; S202: After the preset lead time, control the sampling circuit to sample the output current or input current of the battery and convert it into a sampling voltage; S203: After the preset sampling time, control the sampling circuit to stop outputting; S204: After the preset lag time, control the reset switch to open so that the multi-stage amplification circuit amplifies the sampling voltage to output the amplified sampling voltage; S205: After the preset time, control the comparison circuit to determine whether the sampled voltage after amplification processing is greater than a preset threshold value, so as to determine whether the output current or input current of the battery is greater than a preset current threshold value; S206: After a preset comparison time, return to step S201.

4. The control method of the over-current protection circuit according to claim 3, characterized in that The multi-stage amplification circuit includes a first amplifier, a second amplifier, a first amplification switch, a second amplification switch, and a third amplification switch; the positive input terminal of the first amplifier is connected to the first output terminal of the sampling circuit, and the negative input terminal is connected to the second output terminal of the sampling circuit; the positive input terminal of the second amplifier is connected to the negative output terminal of the first amplifier, the negative input terminal is connected to the positive output terminal of the first amplifier, the negative output terminal is the negative output terminal of the multi-stage amplification circuit, and the positive output terminal is the positive output terminal of the multi-stage amplification circuit; the first terminal of the first amplification switch is connected to the positive input terminal of the first amplifier, and the second terminal is connected to the negative output terminal of the first amplifier; the first terminal of the second amplification switch is connected to the negative input terminal of the first amplifier, and the second terminal is connected to the positive output terminal of the first amplifier; the first terminal of the third amplification switch is connected to the negative output terminal of the first amplifier, and the second terminal is connected to the positive output terminal of the first amplifier; After controlling the reset switch to close, it further includes: When the sampling circuit samples the output current or input current of the battery and converts it into a sampled voltage, control the first amplification switch and the second amplification switch to close; When the sampling circuit stops outputting, control the first amplification switch and the second amplification switch to open, and control the third amplification switch to close; When the reset switch is open, control the third amplification switch to open.

5. The control method of the overcurrent protection circuit according to claim 1, characterized in that, The sampling circuit includes a sampling resistor, a switching switch, a control switch, and a sampling capacitor connected in sequence; Controlling the sampling circuit to sample the output current or input current of the battery and convert it into a sampled voltage, and at the same time controlling the output reset of the multi-stage amplification circuit, includes: Controlling the switching switch at a preset frequency, so that the sampling circuit samples the output current or input current of the battery at the preset frequency, and at the same time controls the output reset of the multi-stage amplification circuit; Controlling the control switch so that the sampling capacitor converts the input current or output current sampled by the sampling capacitor into the sampled voltage.

6. The control method of the overcurrent protection circuit according to any one of claims 1-5, characterized in that The comparison circuit includes a comparator and a latch; Controlling the comparison circuit to determine whether the sampled voltage after amplification processing is greater than a preset threshold value at the preset time after the multi-stage amplification circuit starts amplification processing, so as to determine whether the output current or input current of the battery is greater than a preset current threshold value, includes: Controlling the comparator to determine whether the sampled voltage after amplification processing is greater than a preset threshold value at the preset time after the multi-stage amplification circuit starts amplification processing, and when it is greater, making the latch output a high level, and when it is not greater, making the latch output a low level; When the latch outputs the high level, it is determined that the output current or input current of the battery is greater than a preset current threshold; When the latch outputs the low level, it is determined that the output current or input current of the battery is not greater than a preset current threshold.

7. A control device for an overcurrent protection circuit, characterized in that, Comprising: a memory for storing a computer program; a processor for implementing the steps of the control method of the overcurrent protection circuit according to any one of claims 1 to 6 when executing the computer program.

8. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the control method of the overcurrent protection circuit according to any one of claims 1 to 6 are implemented.

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