Battery protection circuit and overcurrent protection method

Abstract

The present disclosure provides a battery protection circuit, comprising: a detection subcircuit, used to detect the temperature of a target circuit, and output a detection voltage based on the temperature of the target circuit; a control subcircuit, the control subcircuit is connected to the detection subcircuit, and is used to compare the detection voltage with a reference voltage to obtain a first comparison signal, and determine a temperature compensation voltage based on the first comparison signal, and compare the temperature compensation voltage with a target voltage of the target circuit to obtain an overcurrent control signal to control overcurrent protection. The present disclosure also provides an overcurrent protection method.

Description

Technical Field

[0001] The present disclosure relates to the technical field of battery protection, and in particular to a battery protection circuit and an overcurrent protection method. Background Art

[0002] Currently, the charging power of electronic devices is getting higher and higher, and the charging current of batteries is increasing. The high impedance of existing battery circuits makes it difficult to solve the problem of high battery temperature rise caused by fast charging, which affects the user experience of electronic devices and poses a safety hazard. Summary of the invention

[0003] In view of this, the present disclosure provides a battery protection circuit and an overcurrent protection method.

[0004] One aspect of the present disclosure provides a battery protection circuit, including: a detection subcircuit, used to detect the temperature of a target circuit, and output a detection voltage based on the temperature of the target circuit; a control subcircuit, the control subcircuit is connected to the detection subcircuit, and is used to compare the detection voltage with a reference voltage to obtain a first comparison signal, and determine a temperature compensation voltage based on the first comparison signal, and compare the temperature compensation voltage with a target voltage of the target circuit to obtain an overcurrent control signal to control overcurrent protection.

[0005] According to an embodiment of the present disclosure, the target circuit includes a substrate circuit copper skin; the control subcircuit is connected to the target circuit through a detection subcircuit, and the control subcircuit is used to receive a detection voltage determined by the detection subcircuit based on the temperature of the substrate circuit copper skin.

[0006] According to an embodiment of the present disclosure, the detection subcircuit includes: a detection resistor, a first end of the detection resistor is connected to the target circuit, a second end of the detection resistor is connected to the control subcircuit, and the detection resistor is used to output a detection voltage to the control subcircuit; the detection resistor is arranged close to the copper skin of the substrate circuit, and the copper skin temperature is detected based on the impedance of the copper skin of the substrate circuit.

[0007] According to an embodiment of the present disclosure, the control subcircuit includes: a first comparison unit, electrically connected to the detection subcircuit, for comparing the detection voltage from the detection subcircuit with the reference voltage of the first comparison unit, and outputting a first comparison signal; a selection unit, electrically connected to the first comparison unit, for receiving the first comparison signal, and under the control of the first comparison signal, determining a temperature compensation voltage from a plurality of compensation voltage values ​​and outputting the temperature compensation voltage; a second comparison unit, electrically connected to the selection unit and the target circuit, respectively, for obtaining a target voltage of the target circuit, comparing the target voltage with the temperature compensation voltage, and outputting an overcurrent control signal.

[0008] According to an embodiment of the present disclosure, the first comparison unit includes multiple first comparators, and the multiple first comparators are combined to form a reference voltage with different gears; the first comparison unit obtains a first comparison signal based on the comparison between the detection voltage and the reference voltage, and the first comparison signal is determined based on the output level state of the multiple first comparators.

[0009] According to an embodiment of the present disclosure, the selection unit includes multiple first selectors and a second selector, the first selector is used to receive a first comparison signal, and under the control of the first comparison signal, determine at least one selection voltage from multiple compensation voltage values; the second selector is used to determine a temperature compensation voltage from at least one selection voltage provided by the first selector under the control of the second comparison signal, and output the temperature compensation voltage to the second comparison unit, wherein the second comparison signal is determined based on the temperature drift characteristics of the copper skin of the substrate circuit in the target circuit.

[0010] According to an embodiment of the present disclosure, the target circuit is provided with a first switch unit and a second switch unit, and the control subcircuit includes a control unit, which is electrically connected to the first switch unit and the second switch unit. The control unit controls the conduction state of the first switch unit and / or the second switch unit based on an overcurrent control signal to achieve overcurrent protection.

[0011] Another aspect of the present disclosure also provides an overcurrent protection method, including: in response to detecting the temperature of a target circuit, outputting a detection voltage based on the temperature of the target circuit; in response to comparing the detection voltage with a reference voltage of a control subcircuit, obtaining a first comparison signal, and determining a temperature compensation voltage based on the first comparison signal; in response to comparing the temperature compensation voltage with a target voltage of the target circuit, obtaining an overcurrent control signal to control overcurrent protection.

[0012] According to an embodiment of the present disclosure, the temperature compensation voltage is determined based on a first comparison signal and a second comparison signal, wherein the second comparison signal is determined in the following manner: by detecting the temperature of the copper foil of the substrate circuit of the target circuit; testing the resistance change of the copper foil of the substrate circuit at different temperatures, because the resistance of the copper foil at different temperatures is different due to the temperature drift characteristics; determining the adjustment value for the temperature compensation voltage at different temperatures based on the resistance change; storing the adjustment value in a register of the protection circuit before the circuit board is packaged or after the circuit board is mounted; and generating a second comparison signal based on the adjustment value of the register.

[0013] According to an embodiment of the present disclosure, the method includes: detecting the temperature of the substrate circuit copper of the target circuit through a detection subcircuit; comparing the detection voltage of the detection subcircuit with the reference voltage of the first comparison unit in response to the detection voltage, and outputting a first comparison signal; determining the temperature compensation voltage in the selection unit from a plurality of compensation voltage values ​​and outputting the temperature compensation voltage in response to the control of the first comparison signal and the second comparison signal; comparing the temperature compensation voltage with the target voltage of the target circuit obtained by the second comparison unit in response to the temperature compensation voltage, and outputting an overcurrent control signal; and controlling the conduction state of the switch unit of the target circuit in response to the overcurrent control signal to achieve overcurrent protection.

[0014] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0016] Figure 1 The structure diagram of the battery protection circuit according to the embodiment of the present disclosure is schematically shown;

[0017] Figure 2A The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown;

[0018] Figure 2B The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown;

[0019] Figure 3 The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown;

[0020] Figure 4 The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown;

[0021] Figure 5 The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown;

[0022] Figure 6 A flow chart of an overcurrent protection method according to an embodiment of the present disclosure is schematically shown;

[0023] Fig. 7A The production flow chart of the battery protection circuit according to the embodiment of the present disclosure is schematically shown;

[0024] Figure 7BA production flow chart of a battery protection circuit according to another embodiment of the present disclosure is schematically shown; and

[0025] Figure 8 A flow chart of an overcurrent protection method according to another embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Various details of the embodiments of the present disclosure are included to facilitate understanding, and they should be considered as merely exemplary. Therefore, it should be appreciated by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Likewise, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0027] In the technical solution of the present disclosure, the collection, storage, use, processing, transmission, provision, disclosure and application of the data involved (including but not limited to user personal information) comply with the provisions of relevant laws and regulations, take necessary confidentiality measures, and do not violate public order and good morals.

[0028] In one example, the battery protection circuit detects the current in the loop by using a high-precision detection resistor, and disconnects the battery's charge and discharge loop by laser melting the fuse or shutting down the loop transistor when overcurrent occurs, thereby achieving battery protection. However, the increased detection resistor will increase the resistance in the battery charge and discharge loop and occupy part of the circuit board layout space. Therefore, this circuit design will affect the temperature of the circuit board when the battery is charged and discharged, causing the temperature of the circuit to accumulate when the battery is charged and discharged at a high current, and the temperature rise of the electronic equipment will be further increased.

[0029] Based on the above problems, the present disclosure provides a battery protection circuit that can perform overcurrent detection without occupying the circuit board layout, reduce the temperature rise of the circuit board during charging, reduce the loss of detection accuracy caused by the temperature rise, and improve the user experience. Figure 1-Figure 5 The battery protection circuit of the present disclosure is further described.

[0030] Figure 1 The structure diagram of the battery protection circuit according to the embodiment of the present disclosure is schematically shown.

[0031] like Figure 1 As shown, the battery protection circuit 100 of this embodiment includes a detection subcircuit 110 , a control subcircuit 120 and a target circuit 130 .

[0032] In the embodiment of the present disclosure, the detection subcircuit 110 is electrically connected to the control subcircuit 120, and the detection subcircuit 110 is electrically connected to the target circuit 130. The control subcircuit 120 is electrically connected to the target circuit 130, and the control subcircuit 120 is used to output an overcurrent compensation signal DETDI, and the overcurrent compensation signal DETDI is used to indicate whether a charging overcurrent situation occurs, so as to implement overcurrent protection.

[0033] According to an embodiment of the present disclosure, the detection subcircuit 110 is used to detect the temperature of the target circuit 130 , and output a detection voltage based on the temperature of the target circuit 130 .

[0034] In an embodiment of the present disclosure, the target circuit 130 may be a substrate circuit. During the charging and discharging process of the electronic device, the temperature of the substrate circuit changes due to the heat generated by the current flowing through the loop. The detection subcircuit 110 may use a temperature sensor, a thermistor, a thermocouple or other temperature measuring element to detect the temperature of the target circuit 130. Based on the temperature on the target circuit 130, the detection subcircuit 110 will output a detection voltage corresponding to the temperature, and when the temperature on the target circuit 130 changes, the detection voltage output by the detection subcircuit 110 will also change accordingly.

[0035] For example, when the battery is discharged, the temperature of the substrate circuit is 25 degrees, and the detection voltage output by the detection subcircuit based on the substrate circuit temperature is 1.5V.

[0036] For example, when the battery is charging, the temperature of the substrate circuit rises from 27 degrees to 30 degrees due to the continuous heat generation in the circuit, and the detection voltage output by the detection subcircuit based on the substrate circuit temperature changes from 2V to 3V.

[0037] According to an embodiment of the present disclosure, the control subcircuit 120 is connected to the detection subcircuit 110, and the control subcircuit 120 is used to compare the detection voltage with the reference voltage to obtain a first comparison signal, and determine the temperature compensation voltage based on the first comparison signal, and compare the temperature compensation voltage with the target voltage of the target circuit to obtain an overcurrent compensation signal DETDI to control overcurrent protection.

[0038] In an embodiment of the present disclosure, the control subcircuit 120 may receive a detection voltage output by the detection subcircuit 110. The reference voltage may be a voltage signal pre-set inside the control subcircuit 120, and one or more reference voltages may be set. A first comparison signal is obtained by comparing the detection voltage with the reference voltage inside the control subcircuit 120. The first comparison signal is used to characterize the comparison result between the detection voltage and the reference voltage. The temperature compensation voltage may be selected from the reference voltages of different gears built into the control subcircuit 120, and a reference voltage corresponding to the first comparison signal is selected from the reference voltages of different gears based on the first comparison signal as the temperature compensation voltage.

[0039] For example, three reference voltages may be set inside the control subcircuit, which are 1 V, 2 V and 3 V. The comparison result between the detection voltage and the three reference voltages corresponds to the first comparison signal, which is a three-digit digital signal.

[0040] For example, the target circuit temperature is 25 degrees, and the detection voltage received by the control subcircuit is 1.5V. The comparison results of the detection voltage and the reference voltage are 1, 0, and 0 respectively, and the corresponding first comparison signal is obtained. The temperature compensation voltage determined based on the first comparison signal is the compensation voltage value corresponding to the circuit temperature of 25 degrees.

[0041] In the embodiments of the present disclosure, since the temperature of the substrate circuit will rise during charging and discharging, the voltage drop of the substrate circuit will also change with the temperature under the influence of the temperature drift characteristics. The target voltage of the target circuit 130 refers to the voltage on both sides of the substrate circuit. When the substrate circuit is at different temperatures, when the target voltage exceeds a certain voltage value, it is easy to affect the performance and cause safety problems. The temperature compensation voltage can be the maximum value of the target voltage within the safe range at different temperatures.

[0042] For example, the temperature compensation voltage determined based on the first comparison signal is 8 mV. The target voltage of the target circuit is 6 mV. If the target voltage is less than the temperature compensation voltage, the output overcurrent protection signal indicates that overcurrent protection is not required.

[0043] For example, the temperature compensation voltage determined based on the first comparison signal is 8 mV. The target voltage of the target circuit is 12 mV. If the target voltage is greater than the temperature compensation voltage, the output overcurrent protection signal indicates that overcurrent protection is required.

[0044] According to the embodiments of the present disclosure, by detecting the temperature of the substrate circuit, the detection voltage is compared with the preset reference voltage to select the overcurrent gear corresponding to the temperature, and it is determined whether an overcurrent situation occurs during charging and discharging, so as to perform overcurrent protection. The present disclosure removes the detection resistor used to directly detect whether there is an overcurrent, and adopts a battery protection scheme that directly detects the temperature of the substrate circuit and determines the overcurrent, which can reduce the impact of the temperature rise on the current detection accuracy during charging and discharging, and changes the circuit layout to reduce heat accumulation and avoid the temperature rising too fast, thereby improving the user experience and reducing safety hazards.

[0045] Figure 2A The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown.

[0046] like Figure 2A As shown, the battery protection circuit 200 of this embodiment includes a battery, a detection subcircuit 110 , a control subcircuit 120 and a target circuit 130 .

[0047] In an embodiment of the present disclosure, the control subcircuit 120 may be an integrated circuit chip (IC chip), the positive electrode of the battery is electrically connected to the VDD (Virtual Device Driver) terminal of the control subcircuit 120, and the negative electrode of the battery is electrically connected to the VSS (Voltage Source Series, common connection) terminal of the control subcircuit 120. The control subcircuit 120 electrically connects the VDD terminal and the VSS terminal to the positive and negative electrodes of the battery to obtain the working voltage. One end of the detection subcircuit 110 is electrically connected to the VSS terminal of the control subcircuit 120, and the other end of the detection subcircuit 110 is electrically connected to the TH terminal (Threshold, threshold terminal) of the control subcircuit 120, and the TH terminal is used to receive the detection voltage of the detection subcircuit 110 and compare it with the comparator inside the control subcircuit 120. One end of the target circuit 130 is electrically connected to the negative electrode of the battery, and the other end of the target circuit 130 is electrically connected to the VINI terminal (Voltage Input, overcurrent detection terminal), DO terminal (Discharge Output, discharge control terminal) and CO terminal (Charge Output, charge control terminal) of the control subcircuit 120. Among them, the VINI terminal is used to receive the overcurrent voltage so that the control subcircuit 120 can determine whether the overcurrent situation occurs, the DO terminal is used to change the discharge situation of the battery under the control of the control subcircuit 120, and the CO terminal is used to change the charge situation of the battery under the control of the control subcircuit 120.

[0048] In an embodiment of the present disclosure, when the battery is charged, the positive and negative electrodes of the battery are electrically connected to the power supply terminal; when the battery is discharged, the positive and negative electrodes of the battery are electrically connected to the electronic device so that the battery can supply power to the electronic device. The target circuit 130 is electrically connected to the negative electrode of the battery, and the control subcircuit compares the temperature compensation voltage with the target voltage of the target circuit 130 by determining the corresponding temperature compensation voltage at different temperatures. When the target voltage is greater than the temperature compensation voltage, it means that the battery is in an overcurrent state, and the control subcircuit outputs an overcurrent control signal to control the target circuit 130 to disconnect, so that the battery stops charging and discharging to achieve overcurrent protection.

[0049] According to an embodiment of the present disclosure, the target circuit 130 includes a substrate copper sheet 231. The control subcircuit 120 is connected to the target circuit 130 through the detection subcircuit 110, and the control subcircuit 120 is used to receive a detection voltage determined by the detection subcircuit 110 based on the temperature of the substrate copper sheet 231.

[0050] In an embodiment of the present disclosure, the TH terminal of the control subcircuit 120 is electrically connected to one end of the detection subcircuit 110, and the other end of the control subcircuit 110 is electrically connected to the substrate circuit copper skin 231 in the target circuit 130. The substrate circuit copper skin refers to the wire in the battery protection circuit, and specifically refers to the copper wire portion connecting the negative electrode of the battery and the VINI terminal of the control subcircuit 120. When the battery is charged and discharged, the substrate circuit copper skin 231 will produce a voltage drop due to the large current of charging and discharging, and the temperature of the copper skin surface will gradually rise. The detection subcircuit 110 determines the detection voltage according to the temperature of the substrate circuit copper skin 231, and outputs the detection voltage to the control subcircuit 120.

[0051] For example, when the battery is charged, the temperature of the substrate circuit copper sheet 231 rises to 30 degrees, and the target voltage of the target circuit 130 is 7mV. In response to the temperature change, the detection subcircuit 110 outputs the detection voltage to the control subcircuit 120. The control subcircuit 120 determines the temperature compensation voltage corresponding to the current temperature of 30 degrees based on the detection voltage, and compares the temperature compensation voltage with the target voltage to determine whether to perform overcurrent protection.

[0052] According to the embodiments of the present disclosure, by detecting the temperature of the copper foil of the substrate circuit, it is determined whether the voltage of the substrate circuit at the current temperature exceeds the safety threshold to judge whether there is overcurrent. Compared with the use of precise detection resistors, the present disclosure removes the detection resistors, increases the circuit board layout space, and changes the battery charging and discharging circuit layout, evenly distributes the devices on the circuit board, reduces heat accumulation, reduces the temperature increase during charging without affecting the circuit board layout, and can effectively solve the problem of high copper foil temperature drift.

[0053] Based on the overcurrent protection scheme adopted in this application, without reducing the overcurrent detection accuracy, when charging with a current of 12.4A, the internal resistance is reduced by 2.5-6.5mΩ compared to before the improvement, the temperature rise during charging is reduced by 3-10℃, the constant current time is increased by 1-2 minutes, and the overall charging time is reduced by 3-7 minutes. Without affecting the use of the battery, the charging current can be further increased, and the overcurrent protection scheme of this application has a greater advantage.

[0054] According to an embodiment of the present disclosure, the detection subcircuit 110 includes a detection resistor R SEL , the detection resistor R SEL The first end of the detection resistor R SEL The second end of the detection resistor R SEL Used to output the detection voltage to the control sub-circuit 120; the detection resistor R SEL It is closely arranged on the copper sheet 231 of the substrate circuit to detect the temperature of the copper sheet.

[0055] In the embodiment of the present disclosure, the detection voltage refers to the detection resistance R SEL The voltage on both sides. The detection resistor R SEL It can be a thermistor, for example, a positive temperature coefficient thermistor (Positive Temperature Coefficient thermistor, PTC thermistor) or a negative temperature coefficient thermistor (Negative Temperature Coefficient thermistor, NTC thermistor). SEL When it is a PTC thermistor, the resistance value will increase with the increase of temperature. SEL When it is an NTC thermistor, the detection resistor R SEL The resistance value decreases with the increase of temperature. Therefore, the temperature of the substrate circuit copper sheet 231 is related to the detection resistor R SEL The voltages on both sides correspond to each other, and when the temperature of the substrate circuit copper sheet 231 changes, the detection resistor R SEL The voltage on both sides will also change accordingly.

[0056] For example, when the battery is charging, the temperature of the copper skin of the substrate circuit is 25 degrees. Affected by the temperature of the copper skin of the substrate circuit, the detection resistor R SEL The detection voltage on both sides is 1.6V, and the detection resistor R SEL The detection voltage is output to the control sub-circuit 120 .

[0057] For example, when the battery is charging, the temperature of the copper skin of the substrate circuit rises from 30 degrees to 40 degrees. Affected by the temperature of the copper skin of the substrate circuit, the detection resistor R SEL The detection voltage on both sides is increased from 2V to 2.2V, and the detection resistor R SEL The changed detection voltage is output to the control sub-circuit 120 .

[0058] According to an embodiment of the present disclosure, the target circuit 130 is provided with a first switch unit 232 and a second switch unit 233, and the control subcircuit 120 includes a control unit, which is electrically connected to the first switch unit 232 and the second switch unit 233. The control unit controls the conduction state of the first switch unit 232 and / or the second switch unit 233 based on an overcurrent control signal to achieve overcurrent protection.

[0059] In an embodiment of the present disclosure, the first switch unit 232 and the second switch unit 233 may be elements such as field effect transistors or insulated gate double-acting transistors. The control unit in the control subcircuit 120 is electrically connected to the first switch unit 232 via the DO terminal, and the control unit in the control subcircuit 120 is electrically connected to the second switch unit 233 via the CO terminal. When the overcurrent control signal indicates that overcurrent protection is required, the control unit controls the first switch unit 232 and / or the second switch unit 233 to be disconnected through the overcurrent control signal. When the temperature drops or the target voltage is less than a certain threshold, the control unit controls the first switch unit 232 and / or the second switch unit 233 to be turned on.

[0060] In an embodiment of the present disclosure, the control unit may include a delay circuit and a level converter. The delay circuit is used to output a delay signal within a certain time after receiving an overcurrent control signal. The level converter can change the level of the input signal and output it.

[0061] Specifically, in the control subcircuit 120, when the overcurrent control signal indicates an overcurrent condition, after determining that the overcurrent time exceeds the preset time of the delay circuit, the delay circuit will output a delay signal to determine that the charging current or discharging current of the battery has an overcurrent condition. The delay signal is converted by the level converter and output to the first switch unit 232 via the DO terminal or to the second switch unit 233 via the CO terminal, thereby realizing overcurrent control.

[0062] For example, when the battery is discharged, the target voltage of the target circuit 130 is greater than the temperature compensation voltage, and an overcurrent control signal representing overcurrent is obtained, and the overcurrent control signal is high level. When the delay circuit inside the control unit receives the overcurrent control signal for 5 seconds, it outputs a high level delay signal to the level converter, and the level converter converts the high level of the signal to a low level and outputs it to the gate of the first switch unit 232 through the DO terminal. Under the control of the low level signal, the first switch unit 232 is disconnected, thereby disconnecting the connection between the battery and the load.

[0063] For example, when the battery is charged, the target voltage of the target circuit 130 is greater than the temperature compensation voltage, and an overcurrent control signal representing overcurrent is obtained, and the overcurrent control signal is high level. When the delay circuit inside the control unit receives the overcurrent control signal for 5 seconds, it outputs a high level delay signal to the level converter, and the level converter converts the high level of the signal to a low level and outputs it to the gate of the second switch unit 233 through the CO terminal. Under the control of the low level signal, the second switch unit 233 is disconnected, thereby disconnecting the connection between the battery and the power supply.

[0064] In an embodiment of the present disclosure, after overcurrent protection is implemented, when a temperature drop is detected or a target voltage of the target circuit 130 is less than a certain threshold, the first switch unit 232 and / or the second switch unit 233 can be controlled to turn on to restore the battery charging and discharging condition.

[0065] For example, when an overcurrent occurs during battery charging and the second switch unit 233 is controlled to be disconnected, when the target voltage of the target circuit 130 is less than a certain threshold, the overcurrent control signal will change from a high level to a low level, indicating that the battery charging and discharging is restored. When the delay circuit inside the control unit receives the overcurrent control signal for 5 seconds, it outputs a low-level delay signal to the level converter, and the level converter converts the low level of the signal to a high level and outputs it to the gate of the second switch unit 233 through the CO terminal. Under the control of the high-level signal, the second switch unit 233 is turned on, so that the battery resumes charging.

[0066] According to the embodiments of the present disclosure, by comparing the voltage on both sides of the copper foil of the substrate circuit with the temperature compensation voltage, an overcurrent control signal is obtained, and the switch unit is accurately controlled to be turned on or off, thereby realizing overcurrent protection during the operation of the battery, improving the user experience and reducing safety hazards.

[0067] Figure 2B The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown.

[0068] like Figure 2B As shown, the battery protection circuit 200 of this embodiment includes a battery, a detection sub-circuit 110 , a control sub-circuit 120_1 , a control sub-circuit 120_2 , and a target circuit 130 .

[0069] In the embodiments of the present disclosure, the control subcircuit 120 may be an IC chip. In the event that a single chip protection fails in actual applications and authentication scenarios, two IC chips may be used simultaneously to implement overcurrent protection to better protect the safe operation of the battery.

[0070] Figure 3 The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown.

[0071] like Figure 3 As shown, the battery protection circuit 300 includes a detection subcircuit 110, a control subcircuit 120 and a substrate circuit copper foil 231 in the target circuit. The detection subcircuit 110 in the battery protection circuit 300 and the substrate circuit copper foil 231 in the target circuit are similar to the above description and will not be repeated for simplicity.

[0072] According to an embodiment of the present disclosure, the control subcircuit 120 includes a first comparing unit 321 , a selecting unit 322 , and a second comparing unit 323 .

[0073] The first comparison unit 321 is electrically connected to the detection sub-circuit 110 , and is used to compare the detection voltage from the detection sub-circuit 110 with the reference voltage Vref of the first comparison unit 321 , and output a first comparison signal DET.

[0074] In an embodiment of the present disclosure, the first comparison unit 321 may include a comparator, one input terminal of the comparator receives the detection voltage of the detection subcircuit 110, and the other input terminal is a preset reference voltage Vref, and the level value of the first comparison signal DET of the comparator is determined after comparison.

[0075] For example, after comparison by the comparator, if the detection voltage is less than the reference voltage, the level value of the first comparison signal DET output by the comparator may be 0. If the detection voltage is greater than the reference voltage, the level value of the first comparison signal DET output by the comparator may be 1.

[0076] The selection unit 322 is electrically connected to the first comparison unit 321, and is used to receive the first comparison signal DET, and determine the temperature compensation voltage V from a plurality of compensation voltage values ​​under the control of the first comparison signal DET. RDI And output temperature compensation voltage V RDI .

[0077] In an embodiment of the present disclosure, the selection unit 322 may include a selector. Each compensation voltage value set in the selector may correspond to a different temperature level. The temperature level at which the detection voltage is located is determined by a comparator, and the temperature level is sent to the selection unit 322 in the form of a first comparison signal DET. The selection unit 322 determines the compensation voltage value of the corresponding level as the temperature compensation voltage V based on the first comparison signal DET. RDI .

[0078] For example, the level value of the first comparison signal DET is 0, which may correspond to the first temperature level. The selection unit 322 determines the compensation voltage value corresponding to the first temperature level as the temperature compensation voltage based on the first comparison signal DET.

[0079] For example, the level value of the first comparison signal DET is three digits 010, which may correspond to the third temperature level. The selection unit 322 determines the compensation voltage value corresponding to the third temperature level as the temperature compensation voltage based on the first comparison signal DET.

[0080] The second comparison unit 323 is electrically connected to the selection unit 323 and the target circuit, respectively, and is used to obtain the target voltage of the target circuit and compare the target voltage with the temperature compensation voltage V RDI After comparison, an overcurrent control signal DETDI is output.

[0081] In the embodiment of the present disclosure, the second comparison unit 323 may include a comparator. The first input terminal of the comparator is electrically connected to the selection unit 323, and the second input terminal of the comparator is electrically connected to the substrate circuit copper sheet 231 in the target circuit through the VINI terminal of the control subcircuit 120. The comparator receives the temperature compensation voltage V output by the selection unit 323. RDI , compared with the target voltage of the target circuit, and output an overcurrent control signal DETDI.

[0082] For example, the temperature of the target circuit is 27 degrees. The second comparison unit receives the corresponding temperature compensation voltage of 11mV output by the selection unit, and the voltage drop on both sides of the copper foil of the substrate circuit in the target circuit is 7mV. After comparison, the overcurrent control signal DETDI indicating no overcurrent is output.

[0083] For example, the temperature of the target circuit is 35 degrees. The second comparison unit receives the corresponding temperature compensation voltage output by the selection unit as 15mV, and the voltage drop on both sides of the copper foil of the substrate circuit in the target circuit is 27mV. After comparison, the overcurrent control signal DETDI representing overcurrent is output.

[0084] According to the embodiments of the present disclosure, multiple levels of overcurrent detection voltages corresponding to the copper skin temperature are integrated in the IC chip, and the overcurrent detection voltage of the corresponding level is determined by the detection voltage input by the detection resistor, and it is compared with the target voltage of the target circuit to determine whether to perform overcurrent protection. The present disclosure detects the real-time temperature of the copper skin, selects the compensation voltage of the corresponding level for comparison, and determines whether there is overcurrent, which can solve the influence of the high temperature drift of the copper skin of the substrate circuit on the detection accuracy, and maintain the detection accuracy while reducing the cost.

[0085] Figure 4 The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown.

[0086] like Figure 4 As shown, the battery protection circuit 400 of this embodiment includes a detection subcircuit 110, a control subcircuit 120, and a substrate circuit copper foil 231 in the target circuit. The detection subcircuit 110 in the battery protection circuit 400 and the substrate circuit copper foil 231 in the target circuit are similar to the above description, and will not be repeated for simplicity.

[0087] According to an embodiment of the present disclosure, the control subcircuit 120 includes a first comparing unit 321 , a selecting unit 322 , and a second comparing unit 323 .

[0088] According to an embodiment of the present disclosure, the first comparison unit 321 includes a plurality of first comparators, and the plurality of first comparators are combined to form a reference voltage Vref with different gears. The first comparison unit 321 is based on the detection voltage V RSELA first comparison signal is obtained by comparing with the reference voltage Vref, and the first comparison signal is determined based on the output level states of the plurality of first comparators.

[0089] In the embodiment of the present disclosure, the first comparison unit 321 may include a plurality of comparators COM1, COM2, ..., COMn, each of which includes two input terminals. The first input terminal is the detection voltage V input by the detection subcircuit 110. RSEL The second input terminal is a pre-set multi-level reference voltage. The comparator is used to detect the voltage V RSEL The first comparison signal DET is formed by the comparison result of at least one comparator.

[0090] For example, Figure 4 As shown, the first comparison unit 321 is provided with three comparators COM1, COM2 and COM3. The reference voltage of COM1 is Vref1, the reference voltage of COM2 is Vref2, and the reference voltage of COM3 is Vref3. For example, the above three reference voltages can be set to Vref1 <Vref2 <Vref3。

[0091] By comparing the reference voltage with three comparators respectively, four temperature levels can be determined for the detection voltage. They are less than Vref1, greater than or equal to Vref1 and less than Vref2, greater than or equal to Vref2 and less than Vref3, and greater than or equal to Vref3. The three-bit comparison results DET1, DET2, and DET3 can be obtained respectively through the output terminals of the three comparators, and the three-bit level values ​​are combined as the first comparison signal DET<3:1>.

[0092] For example, the reference voltages of the three first comparators are 1V, 3V and 5V respectively. RSEL It is divided into 4 gears, namely less than 1V, greater than or equal to 1V and less than 3V, greater than or equal to 3V and less than 5V, and greater than or equal to 5V.

[0093] For example, when receiving the detection voltage V RSEL When it is 1.5V, the three comparison results can be 1, 0, 0 respectively, and the first comparison signal DET is 100.

[0094] For example, when receiving the detection voltage V RSEL When the voltage is 4.5V, the three comparison results can be 1, 1, and 0 respectively, and the first comparison signal DET is 110.

[0095] In the embodiment of the present disclosure, the selection unit 322 may include a selector, the input end of the selector is the first comparison signal DET, and the selector selects from a plurality of compensation voltage values ​​VDI. <1> 、VDI <2> 、VDI <n>The compensation voltage value corresponding to the first comparison signal DET is determined as the temperature compensation voltage V RDI The compensation voltage value corresponds to different values ​​of the first comparison signal one by one.

[0096] For example, the level values ​​of the first comparison signal may be 000, 001, 011, and 111. When the first comparison signal DET received by the selection unit 322 is 000, the compensation voltage value VDI may be determined. <1> When the first comparison signal DET received by the selection unit 322 is 001, the compensation voltage value VDI can be determined. <2> When the first comparison signal DET received by the selection unit 322 is 011, the compensation voltage value VDI can be determined. <3> When the first comparison signal DET received by the selection unit 322 is 111, the compensation voltage value VDI can be determined. <4> is the temperature compensation voltage.

[0097] In the embodiment of the present disclosure, the selector can have multiple voltage levels VDI built in. <1> ,…,VDI <n>According to the circuit requirements, the temperature compensation voltage corresponding to different temperatures can be reasonably selected from the multiple voltages built into the selector. By utilizing the characteristic that the external detection resistor changes with temperature, the first comparison unit outputs the first comparison signal corresponding to different temperatures, thereby selecting the temperature compensation voltage corresponding to the first comparison signal one by one.

[0098] For example, six voltage levels can be set inside the selector, namely 7mV, 8mV, 9mV, 10mV, 11mV, and 12mV. During the circuit board testing phase, by testing the overcurrent of the circuit board at different temperatures, the temperature compensation voltage corresponding to different temperatures can be selected from the six voltage levels.

[0099] For example, the first comparison unit includes three comparators, and the level value of the first comparison signal can be 000, 001, 011, and 111, and four temperature gears are obtained after division. In the test, the temperature compensation voltage corresponding to the above four temperature gears is determined, and 8 mV, 9 mV, 10 mV, and 11 mV are selected from the selector, corresponding to the four temperature conditions represented by the first comparison signal. When the selector receives the first comparison signal of 000, the corresponding temperature compensation voltage is 8mV; when the selector receives the first comparison signal of 001, the corresponding temperature compensation voltage is 9 mV; when the selector receives the first comparison signal of 011, the corresponding temperature compensation voltage is 10 mV; when the selector receives the first comparison signal of 111, the corresponding temperature compensation voltage is 11 Mv.

[0100] In the embodiment of the present disclosure, the second comparison unit 323 is similar to the second comparison unit described above, and will not be described again for the sake of brevity.

[0101] According to an embodiment of the present disclosure, a plurality of compensation voltage values ​​may be built into the selection unit, and some of the voltage values ​​may be selected as temperature compensation voltages according to circuit requirements, corresponding one-to-one with different level values ​​of the first comparison signal. The more levels of compensation voltage values ​​there are, the higher the precision and accuracy of the battery protection circuit. The accurate overcurrent voltage can be determined at the corresponding temperature to avoid overcurrent conditions that the battery protection circuit cannot detect, thereby improving the user experience.

[0102] Figure 5 The structure diagram of a battery protection circuit according to another embodiment of the present disclosure is schematically shown.

[0103] like Figure 5 As shown, the battery protection circuit 500 of this embodiment includes a detection subcircuit 110, a control subcircuit 120, and a substrate circuit copper foil 231 in the target circuit. The detection subcircuit 110 in the battery protection circuit 500 and the substrate circuit copper foil 231 in the target circuit are similar to the above description, and will not be repeated for simplicity.

[0104] The detection resistor R in the detection subcircuit 110 SEL It can also be set as a temperature control element such as a thermistor, which has the characteristic that the resistance changes with temperature. The control subcircuit 120 generates a current I flowing from the VDD terminal to the TH terminal. SEL Therefore, the detection voltage V input to the control sub-circuit 120 RSEL =I SEL *R SEL When the battery protection circuit 500 is at different temperatures, the detection resistor R SEL The resistance value will change, so the detection voltage V RSEL The change in the detection voltage will also change with the temperature. The change in the detection voltage can reflect the change in the resistance value of the detection resistor.

[0105] According to an embodiment of the present disclosure, the control subcircuit 120 includes a first comparing unit 321 , a selecting unit 322 , and a second comparing unit 323 .

[0106] According to an embodiment of the present disclosure, the selection unit 322 includes a plurality of first selectors SEL1 and a second selector SEL2. The first selector SEL1 is used to receive the first comparison signal DET <n:1>, and in the first comparison signal DET <n:1>Under the control of , at least one selected voltage is determined from a plurality of compensation voltage values; the second selector SEL2 is used to select at least one selected voltage from a second comparison signal FDI <1> and FDI <0> Under the control of the first selector SEL1, the temperature compensation voltage V is determined from at least one selection voltage provided by the first selector SEL1. RDI , and outputs a temperature compensation voltage V RDI To the second comparison unit 323, wherein the second comparison signal is determined based on the temperature drift characteristics of the copper foil of the substrate circuit in the target circuit.

[0107] In the embodiment of the present disclosure, the first comparison unit 321 may include n comparators, and the first comparison signal DET <n:1>is an n-bit comparison signal obtained by a first comparator based on a reference voltage and a detection voltage. Under the control of the first comparison signal, first selectors SEL11, SEL12, …, SEL1n determine n selection voltages from multiple compensation voltage values and output them to a second selector SEL2. Under the control of the second comparison signal, the second selector SEL2 further determines a temperature compensation voltage V RDI , and outputs it to a second comparison unit 323, so that the second comparison unit 323 compares the temperature compensation voltage V RDI with the target voltage of the target circuit.

[0108] In an embodiment of the present disclosure, the first selector SEL1 determines a compensation voltage value corresponding to a temperature range as a selection voltage based on the level value of the first comparison signal. The selection voltages selected by multiple first selectors are different because the temperature drift characteristics of the copper cladding on the substrate line of the battery protection circuit are different. Compared with the theoretically temperature compensation voltage value, in actual situations, the copper cladding is affected by temperature, resulting in a certain error between the actual temperature compensation voltage value and the theoretical value. Based on the selection voltage selected by the first selector, it is the temperature compensation voltage compensated by different error values. Setting the second selector SEL2 to perform a second selection on the selection voltages compensated by different error values can select a temperature compensation voltage closer to the actual compensation voltage value of the copper cladding.

[0109] In an embodiment of the present disclosure, the input terminal of the second selector SEL2 is a second comparison signal FDI<1:0>, and the second comparison signal FDI<1:0> is determined based on the temperature drift characteristics of the copper cladding on the substrate line in the target circuit. Since there are differences in the copper cladding between circuit boards, affected by the temperature drift characteristics, the overcurrent voltages of different circuit boards at the same temperature are not exactly the same. Therefore, by detecting the copper cladding through the second comparison signal, the overcurrent voltage of each circuit board at the same temperature can be accurately determined. The second comparison signal FDI<1:0> is determined and written into the circuit board register during the circuit board production stage.

[0110] As Figure 5 shown, the first comparison signal DET is a signal output by the first comparison unit based on the detection voltage, corresponding to different temperature ranges. According to the first comparison signal DET, the corresponding compensation voltage value can be selected from multiple first comparators as the selection voltage. Taking the first selector SEL11 as an example, when the detection voltage V RESL <Vref1, the output signals DET_temp1~DET_tempn of all first comparators are low levels. At this time, the output first comparison signal DET_temp can enable the first selector SEL11 to output the selection voltage VDI1_t1<1>. When Vref1<V RSEL When V < Vref2, the output signal DET_temp1 of the first comparator COM1 is at a high level, and the output signals DET_temp2 to DET_tempn of the first comparators COM2 - COMn are all at a low level. At this time, the first comparison signal DET_temp output causes the first selector SEL11 to output the selection voltage VDI1_t1<2>. Similarly, when V RSEL > Vrefn, the output signals DET_temp1 to DET_tempn of the first comparators COM1 - COMn are all at a high level. At this time, the first comparison signal DET_temp output causes the first selector SEL11 to output the selection voltage VDI1_t1 <n>.

[0111] On this basis, the second selection unit generates a second comparison signal FDI <0> 、FDI <1> Under the control of the first selection unit, a more accurate temperature compensation voltage is determined from the multiple selection voltages output by the first selection unit.

[0112] For example, when the battery is charging, when the temperature of the target circuit is 30 degrees, the corresponding temperature compensation voltage is 11mV. Due to the temperature drift characteristics of the copper sheet, the temperature compensation voltage may be any value in the range of 10.5mV-11.5mV after the error value is compensated.

[0113] For example, after testing the copper sheet, the temperature compensation voltage corresponding to the target circuit temperature of 30 degrees on circuit board A is 10.9mV, and the difference with the standard temperature compensation voltage is 0.1 mV. Then, the second comparison signal representing the difference of 0.1mV is written into the circuit board to control the second selector SEL2 to determine the temperature compensation voltage from multiple selection voltages.

[0114] According to the embodiments of the present disclosure, during the fine-tuning stage of the circuit, the register mechanism inside the battery protection chip is utilized to compensate the overcurrent reference voltage based on the error value detected internally, and the internal temperature compensation voltage at different temperatures is accurately determined, thereby reducing the deviation caused by the characteristics of the copper sheet, further improving the detection accuracy, and optimizing the user experience.

[0115] Figure 6 The flowchart of the overcurrent protection method according to the embodiment of the present disclosure is schematically shown.

[0116] like Figure 6 As shown, the overcurrent protection method of this embodiment includes operations S610 to S630.

[0117] In operation S610 , in response to detecting a temperature of a target circuit, a detection voltage is output based on the temperature of the target circuit.

[0118] In the embodiments of the present disclosure, the temperature of the target circuit may refer to the temperature of the copper foil of the substrate circuit. The detection voltage refers to the voltage across the detection resistor. The detection resistor may be a temperature sensing element such as a thermistor or a temperature sensor.

[0119] In operation S620, in response to comparing the detection voltage with the reference voltage of the control subcircuit, a first comparison signal is obtained, and a temperature compensation voltage is determined based on the first comparison signal. The reference voltage and the temperature compensation voltage are both voltage values ​​preset inside the control subcircuit, and the reference voltage is used to compare with the detection voltage and determine the first comparison signal.

[0120] In operation S630, an overcurrent control signal is obtained in response to the temperature compensation voltage being compared with a target voltage of the target circuit to control overcurrent protection. The target voltage refers to the voltage on both sides of the copper foil of the substrate circuit on the target circuit.

[0121] In the embodiment of the present disclosure, the detection resistor changes its resistance under the influence of the temperature of the copper foil of the substrate circuit in the target circuit, so that the current flowing through the detection resistor and the voltage on both sides of the detection circuit change with the temperature. The control subcircuit receives the detection voltage output by the detection resistor, and compares it with the detection voltage through an internal comparator to determine the temperature level corresponding to the detection voltage.

[0122] Through the correspondence between the level value of the first comparison signal and the temperature gear, the temperature compensation voltage corresponding to the current temperature gear is determined from the multiple compensation voltage values ​​built into the selector. The target voltage on both sides of the copper foil of the substrate circuit on the target circuit is obtained, and the target voltage is compared with the temperature compensation voltage to determine whether overcurrent occurs to each other, so as to implement overcurrent protection.

[0123] According to the embodiments of the present disclosure, by reducing the loop impedance of the battery, a thermistor is placed at the copper foil of the substrate circuit, and the temperature of the circuit is detected in real time according to the characteristics of different resistance values ​​at different temperatures, and the temperature compensation voltage within the corresponding temperature range is determined in the protection chip to determine whether there is overcurrent. While reducing the temperature rise, the influence of the circuit board substrate material on the detection accuracy is avoided.

[0124] At present, the production process of ordinary circuit boards is to first produce circuit board wafers, and then write working parameters and other data into the fuses inside the wafers through chip adjustment. Then the wafers are packaged and tested, and circuit board design and proofing are carried out. The circuit board surface is mounted based on the designed circuit drawings, and packaging is carried out after mounting is completed.

[0125] Next, combine Figure 7A-7B The circuit board production process disclosed in the present invention is further described.

[0126] Figure 7A-7B The production flow chart of the battery protection circuit board according to the embodiment of the present disclosure is schematically shown.

[0127] like Fig. 7A As shown, the production process of the battery protection circuit pack of this embodiment includes the following steps.

[0128] In one embodiment, firstly, circuit board design and proofing 711 are performed. Then, steps 712-713 are executed, and for different batches of battery protection circuit boards, the copper resistance of the substrate circuit is tested at different temperatures, the average resistance value of different batches is taken, and the corresponding temperature compensation voltage gear at different temperatures is determined according to the average resistance value. Secondly, after the basic battery protection circuit is obtained through circuit board wafer production 714, circuit parameter adjustment 715 is performed, and the compensation voltage value is written into the IC chip so as to adjust the parameters in the IC chip and optimize the accuracy. Then, packaging test 716 and circuit board surface mounting 717 are performed to obtain the completed battery protection circuit board, and testing 718 and packaging 719 are performed. The battery protection circuit board produced by the above production scheme can directly build multiple fixed temperature compensation voltage gears into the battery protection circuit, while reducing costs and reducing temperature rise, while avoiding the influence of copper on accuracy.

[0129] According to the embodiment of the present disclosure, an NTC is placed at the copper position on the circuit board to add a layer of temperature detection circuit. At different temperatures, the NTC provides the IC chip with the real-time temperature of the detected circuit under different conditions, so that the IC chip determines the temperature compensation voltage level according to the real-time temperature value to compensate for the detected current accuracy to achieve accurate overcurrent protection, reducing the influence of temperature rise and different circuit board materials on the current detection accuracy.

[0130] like Figure 7B As shown, the production process of the battery protection circuit board of this embodiment includes the following steps.

[0131] In another embodiment, it is necessary to first carry out circuit board design and proofing 711. Then, execute steps 712-713, and test the copper resistance of the substrate circuit at different temperatures for different batches of battery protection circuit boards. And determine the error value of the temperature compensation voltage based on the resistance. Secondly, circuit board wafer production 714 is carried out to obtain the basic material that can manufacture the battery protection circuit. After obtaining the basic battery protection circuit through wafer production, packaging test 716 and circuit board surface mounting 717 are directly carried out to obtain the completed battery protection circuit board. Subsequently, the error value of each substrate circuit copper is written into the corresponding circuit board through protection board adjustment 721, and then packaging 719 is carried out. This production scheme collects the corresponding copper resistance at different temperatures, converts it into compensation voltage through calculation and writes it into the circuit, thereby further reducing the accuracy deviation caused by the characteristics of the copper.

[0132] According to the embodiments of the present disclosure, a detection resistor is placed at the location of the copper foil on the circuit board, and an additional layer of temperature detection circuit is added. After the circuit board device patch is completed, the circuit board is placed at different temperatures to collect the impedance values ​​corresponding to the copper foil, and the resistance deviation is converted into a compensation value by calculation, and written into the IC chip by laser fusing. This solution further reduces the accuracy deviation caused by the characteristic differences of the circuit board, and its current accuracy can be achieved to ±1A, while maintaining a high overcurrent detection accuracy while reducing costs. Introducing parameter errors into the circuit board for adjustment can avoid generating too many IC chip models, improve material turnover, and achieve multiple beneficial effects such as shortening the production cycle, reducing costs, and normalizing protection schemes.

[0133] According to an embodiment of the present disclosure, the temperature compensation voltage is determined based on a first comparison signal and a second comparison signal, wherein the second comparison signal is determined in the following manner: by detecting the temperature of the copper foil of the substrate circuit of the target circuit; testing the resistance change of the copper foil of the substrate circuit at different temperatures, because the resistance of the copper foil at different temperatures is different due to the temperature drift characteristics; determining the adjustment value for the temperature compensation voltage at different temperatures based on the resistance change; storing the adjustment value in a register of the protection circuit before the circuit board is packaged or after the circuit board is mounted; and generating a second comparison signal based on the adjustment value of the register.

[0134] In the embodiments of the present disclosure, due to the temperature drift characteristics, when the temperature rises, the resistance of the copper sheet will change, thereby causing the target voltage on both sides of the copper sheet of the substrate circuit to change. Therefore, in the production process of the circuit board, it is necessary to obtain circuit boards of different batches, and test the copper sheet resistance on the substrate circuit at different temperatures, and adjust the circuit based on the resistance data, determine the difference between the circuit board temperature compensation voltage and the standard compensation voltage, and write it into the circuit board through the second comparison signal. The IC chip can be trimmed by PCM trimming (Protection Circuit Module trimming, protection board trimming / fine tuning), so as to achieve the writing of the second comparison signal into the circuit board.

[0135] For example, the circuit board can be placed in a temperature chamber with different temperatures (-10-60°C) to perform discharge and charge tests with different currents. During the test, the voltage across the detection resistor and the resistance value of the detection resistor are recorded, and the relationship between the target voltage and temperature of the target circuit is calculated using the following formula:

[0136] Vsense = (3E-08T 3 - 3E-07T 2 + 0.0094T + 2.4) × I

[0137] Among them, Vsense refers to the target voltage of the target circuit, T refers to the temperature of the circuit board during charging and discharging, and I refers to the current flowing through the detection resistor.

[0138] The temperature compensation value corresponding to different temperatures can be determined by the following formula:

[0139] V error =V SENSE -V 25℃

[0140] Among them, V 25℃ Refers to the theoretical voltage value of the target voltage on the target circuit at 25 degrees Celsius, V error Represents the difference between the temperature compensation voltage of the circuit board and the standard temperature compensation voltage. According to the voltage difference V corresponding to different temperatures error , the temperature compensation voltage in the circuit board is corrected in the form of a second comparison signal, further improving the detection accuracy of the battery protection circuit.

[0141] According to the embodiments of the present disclosure, in the circuit board production process, the error between the copper resistance and the theoretical value is measured, and in the circuit fine-tuning stage, the error value of the copper resistance of the substrate circuit is written into the circuit board by utilizing the register mechanism of the internal parameter adjustment process of the battery protection chip, thereby accurately determining the internal temperature compensation voltage at different temperatures, reducing the deviation caused by the characteristics of the copper resistance, further improving the detection accuracy, and optimizing the user experience.

[0142] Figure 8 A flow chart of an overcurrent protection method according to another embodiment of the present disclosure is schematically shown.

[0143] like Figure 8 As shown, the overcurrent protection method of this embodiment includes operations S801 to S806.

[0144] In operation S801 , in the circuit fine-tuning stage, the error value of the copper foil of the substrate circuit is written into the circuit board in the form of a second comparison signal.

[0145] In the embodiments of the present disclosure, the error value refers to the difference between the standard value and the actual value of the voltage across the copper skin at different temperatures.

[0146] In operation S802 , a temperature of a copper sheet of a substrate circuit of a target circuit is detected by a detection subcircuit.

[0147] In operation S803 , the detection voltage of the detection sub-circuit is compared with the reference voltage of the first comparison unit in response to the detection, and a first comparison signal is output.

[0148] In operation S804 , in response to the control of the first comparison signal and the second comparison signal, a temperature compensation voltage in the selection unit is determined from a plurality of compensation voltage values ​​and the temperature compensation voltage is output.

[0149] In operation S805 , the temperature compensation voltage is compared with a target voltage of the target circuit acquired by the second comparison unit in response to the temperature compensation voltage, and an overcurrent control signal is output.

[0150] In operation S806 , overcurrent protection is implemented by controlling a conduction state of a switch unit of the target circuit in response to the overcurrent control signal.

[0151] In an embodiment of the present disclosure, the temperature of the copper foil of the substrate circuit is detected by a detection subcircuit, and the detection voltage is input into the control subcircuit so that the control subcircuit determines the corresponding temperature gear according to the detection voltage. The temperature gear is sent to the first selector inside the control subcircuit in the form of a first comparison signal, and the first selector determines a plurality of selection voltages corresponding to the temperature gear from the compensation voltage value based on the first comparison signal. The selection voltage is a temperature compensation voltage compensated by different error values. Under the control of the second comparison signal, the second selector selects a voltage value that matches the copper foil error value of the circuit board from the selection voltage as the temperature compensation voltage.

[0152] The temperature compensation voltage output by the second selector is compared with the target voltage on both sides of the copper foil of the substrate circuit to obtain an overcurrent control signal. In response to the overcurrent control signal indicating no overcurrent, the switch unit is kept in the on state. In response to the overcurrent control signal indicating overcurrent, the switch unit is controlled to be disconnected to stop charging and discharging of the battery to achieve overcurrent protection.

[0153] For example, under the control of the first comparison signal, the selection voltages output by the multiple first selectors are 10.4mV, 10.5mV, 10.6mV and 10.7mV. Among them, the error value corresponding to 10.4mV is -0.1, the error value corresponding to 10.5mV is 0, the error value corresponding to 10.6mV is 0.1, and the error value corresponding to 10.7mV is 0.2. Based on the second comparison signal, it can be determined that the error value of the copper foil of the substrate circuit is 0.1, then under the control of the second comparison signal, the temperature compensation voltage output by the second selector is 10.6mV.

[0154] According to the embodiments of the present disclosure, the temperature compensation voltage is selected by using a comparison signal inside the chip and a comparison signal written from the outside during production, which not only reduces the loop impedance but also avoids the error influence caused by the temperature drift characteristics of the copper sheet. It improves the detection accuracy while reducing the cost and temperature rise, reduces the safety hazards caused by battery charging and use, and improves the user experience.

[0155] It should be noted that the collection, storage, use, processing, transmission, provision, disclosure and application of user personal information involved in the technical solution of this disclosure are in compliance with the provisions of relevant laws and regulations, necessary confidentiality measures have been taken, and they do not violate public order and good morals. In the technical solution of this disclosure, the user's authorization or consent is obtained before obtaining or collecting user personal information.

[0156] According to an embodiment of the present disclosure, the program code for executing the computer program provided by the embodiment of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computing programs can be implemented using high-level process and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, Java, C++, python, "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on the remote computing device, or entirely on the remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (for example, using an Internet service provider to connect through the Internet).

[0157] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0158] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or coupled in a variety of ways, even if such combinations and / or couplings are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or coupled in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or couplings fall within the scope of the present disclosure.

[0159] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above, this does not mean that the measures in the various embodiments cannot be used in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.< / n> < / n> < / n>

Claims

1. A battery protection circuit, comprising: a detection subcircuit, configured to detect a temperature of a target circuit and output a detection voltage based on the temperature of the target circuit; A control subcircuit, which is connected to the detection subcircuit, is used to compare the detection voltage with a reference voltage to obtain a first comparison signal, and determine a temperature compensation voltage based on the first comparison signal, and compare the temperature compensation voltage with a target voltage of the target circuit to obtain an overcurrent control signal to control overcurrent protection.

2. According to the circuit of claim 1, the target circuit includes a substrate circuit copper skin; the control subcircuit is connected to the target circuit through a detection subcircuit, and the control subcircuit is used to receive a detection voltage determined by the detection subcircuit based on the temperature of the substrate circuit copper skin.

3. The circuit according to claim 2, wherein the detection subcircuit comprises: a detection resistor, a first end of the detection resistor being connected to the target circuit, a second end of the detection resistor being connected to the control subcircuit, and the detection resistor being used to output the detection voltage to the control subcircuit; The detection resistor is arranged closely on the copper skin of the substrate circuit to detect the temperature of the copper skin.

4. The circuit according to claim 1, wherein the control subcircuit comprises: a first comparison unit, electrically connected to the detection subcircuit, for comparing the detection voltage from the detection subcircuit with the reference voltage of the first comparison unit, and outputting a first comparison signal; a selection unit, electrically connected to the first comparison unit, configured to receive the first comparison signal, and under the control of the first comparison signal, determine a temperature compensation voltage from a plurality of compensation voltage values ​​and output the temperature compensation voltage; The second comparison unit is electrically connected to the selection unit and the target circuit respectively, and is used to obtain a target voltage of the target circuit, compare the target voltage with the temperature compensation voltage, and output the overcurrent control signal.

5. The circuit according to claim 4, wherein the first comparison unit comprises a plurality of first comparators, and the plurality of first comparators are combined to form the reference voltage with different gears; The first comparison unit obtains the first comparison signal based on the comparison between the detection voltage and the reference voltage, and the first comparison signal is determined based on the output level states of the plurality of first comparators.

6. The circuit according to claim 4, The selection unit includes a plurality of first selectors and a second selector, The first selector is used to receive the first comparison signal and determine at least one selection voltage from a plurality of compensation voltage values ​​under the control of the first comparison signal; The second selector is used to determine the temperature compensation voltage from at least one selection voltage provided by the first selector under the control of a second comparison signal, and output the temperature compensation voltage to the second comparison unit, wherein, The second comparison signal is determined based on the temperature drift characteristics of the copper foil of the substrate circuit in the target circuit.

7. The circuit according to claim 1, wherein the target circuit is provided with a first switch unit and a second switch unit, The control subcircuit includes a control unit, which is electrically connected to the first switch unit and the second switch unit. The control unit controls the conduction state of the first switch unit and / or the second switch unit based on the overcurrent control signal to achieve overcurrent protection.

8. An overcurrent protection method, comprising: in response to detecting a temperature of a target circuit, outputting a detection voltage based on the temperature of the target circuit; In response to comparing the detection voltage with a reference voltage of the control subcircuit, a first comparison signal is obtained, and a temperature compensation voltage is determined based on the first comparison signal; In response to comparing the temperature compensation voltage with the target voltage of the target circuit, an overcurrent control signal is obtained to control overcurrent protection.

9. The method according to claim 8, wherein the temperature compensation voltage is determined based on the first comparison signal and the second comparison signal, wherein: The second comparison signal is determined by: By detecting the temperature of the copper skin of the substrate circuit of the target circuit; The resistance change of the copper foil of the substrate circuit is tested at different temperatures. Due to the temperature drift characteristics, the resistance of the copper foil is different at different temperatures. Determining adjustment values ​​for temperature compensation voltage at different temperatures according to the resistance change; Storing the adjustment value in a register of the protection circuit before the circuit board is packaged or after the circuit board is mounted; The second comparison signal is generated based on the adjustment value of the register.

10. The method according to claim 9, comprising: Detecting the temperature of the copper skin of the substrate circuit of the target circuit by a detection subcircuit; In response to comparing the detection voltage of the detection subcircuit with the reference voltage of the first comparison unit, and outputting a first comparison signal; In response to the control of the first comparison signal and the second comparison signal, determine a temperature compensation voltage in a selection unit from a plurality of compensation voltage values ​​and output the temperature compensation voltage; In response to comparing the temperature compensation voltage with the target voltage of the target circuit acquired by the second comparison unit, outputting the overcurrent control signal; In response to the overcurrent control signal, the conduction state of the switch unit of the target circuit is controlled to implement overcurrent protection.

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