Battery protection circuit and method

Abstract

The present application relates to a battery protection circuit and method, which belongs to the technical field of battery protection. The battery protection circuit includes a voltage detection circuit, a current detection circuit and a low-power logic control circuit. The current detection circuit includes an overcurrent detection subcircuit; the low-power logic control circuit is respectively connected to the voltage detection circuit and the overcurrent detection subcircuit for communication, and is used to periodically output a low-power logic control signal to control the voltage detection circuit and the overcurrent detection subcircuit to work periodically. Since the low-power logic control circuit periodically outputs a low-power logic control signal, the voltage detection circuit and the overcurrent detection subcircuit are controlled by the low-power logic control signal to work periodically, and the voltage detection circuit and the overcurrent detection subcircuit do not need to work continuously, thereby reducing the battery power consumed by the battery protection chip when protecting the battery, thereby increasing the battery life.

Description

Technical Field

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

[0002] In mobile devices and wearable devices, the standby current of the electronic devices used should be as low as possible to extend the standby time of the mobile devices and wearable devices. Lithium batteries used in mobile devices need to use battery protection chips to protect the batteries from abnormal voltage or current.

[0003] Reference Figure 1 In the related art, a lithium battery protection chip is disclosed, including a voltage detection circuit 110, a bandgap reference circuit 120, a current detection circuit 140, a drive circuit 130 and a power switch S; the voltage detection circuit 110 is connected to the VDD terminal and the drive circuit 130 respectively, and is used to detect the voltage at both ends of the battery; the drive circuit 130 is connected to the gate of the power switch S, and is used to control the on and off of the power switch S; the source of the power switch S is connected to the GND terminal, the drain of the power switch S is connected to the VM terminal, and it is placed in the battery charging and discharging circuit; the bandgap reference circuit 120 is respectively connected to the VDD terminal, the voltage detection circuit 110 and the current detection circuit 140 for communication, and is used to provide the voltage detection circuit 110 and the current detection circuit 140 with a maximum voltage threshold, a minimum voltage threshold and a reference current; the current detection circuit 140 is respectively connected to the VDD terminal and the drive circuit 130, and is used to detect the current of the battery charging or discharging; the positive electrode of the battery is connected to the VDD terminal, and the negative electrode is connected to the GND terminal; the load or charger is connected between the VDD terminal and the VM terminal.

[0004] When the battery is charging or discharging, the voltage detection circuit 110 detects the voltage at both ends of the battery in real time, and compares the detected voltage value with the maximum voltage threshold and the minimum voltage threshold. If the voltage value is higher than the maximum voltage threshold or lower than the minimum voltage threshold, the drive circuit 130 controls the power switch S to be disconnected, thereby disconnecting the battery charging or discharging circuit; or the current detection circuit 140 detects the charging or discharging current of the battery in real time, and compares the detected current value with the reference current value. If the current value is greater than the reference current value, the drive circuit 130 controls the power switch S to be disconnected, thereby disconnecting the battery charging or discharging circuit; thereby protecting the battery.

[0005] With respect to the above-mentioned related technologies, the inventors believe that since the voltage detection circuit 110 continuously detects the voltage across the battery in real time, the battery protection chip continuously consumes the battery power when protecting the battery, thereby reducing the battery usage time. Summary of the invention

[0006] In order to increase the service life of a battery, the present application provides a battery protection circuit and method.

[0007] In a first aspect, the present application provides a battery protection circuit, which adopts the following technical solution:

[0008] A battery protection circuit comprises a voltage detection circuit, a current detection circuit and a low-power logic control circuit, wherein the current detection circuit comprises an overcurrent detection subcircuit; the low-power logic control circuit is respectively connected to the voltage detection circuit and the overcurrent detection subcircuit for communication, and is used for periodically outputting a low-power logic control signal to control the voltage detection circuit and the overcurrent detection subcircuit to operate periodically.

[0009] By adopting the above technical solution, since the low-power logic control circuit periodically outputs a low-power logic control signal, the voltage detection circuit and the over-current detection sub-circuit are controlled by the low-power logic control signal to perform periodic operation, and the voltage detection circuit and the over-current detection sub-circuit are not required to work continuously, thereby reducing the battery power consumed by the battery protection chip when protecting the battery, thereby increasing the battery life.

[0010] Optionally, the battery protection circuit further includes a bandgap reference circuit, and the low-power logic control circuit is communicatively connected to the bandgap reference circuit for controlling the bandgap reference circuit to operate periodically.

[0011] By adopting the above technical solution, the purpose of controlling the bandgap reference circuit to work periodically by the low-power logic control signal is to further reduce the battery power consumed by the battery protection chip when protecting the battery.

[0012] Optionally, the current detection circuit includes a short-circuit detection subcircuit, and the battery protection circuit further includes a sampling circuit, wherein the sampling circuit is communicatively connected to the bandgap reference circuit and the short-circuit detection subcircuit respectively, and is used for collecting a reference voltage provided by the bandgap reference circuit, so as to enable the short-circuit detection subcircuit to work normally;

[0013] Wherein, the short circuit detection subcircuit works continuously.

[0014] By adopting the above technical solution, the short-circuit detection subcircuit detects the current in the battery discharge circuit, so as to determine whether the battery discharge circuit is short-circuited; in order to ensure that the battery protection circuit can detect the short-circuit state of the battery discharge circuit quickly enough, the short-circuit detection subcircuit needs to work continuously, but since the bandgap reference circuit works periodically under the low-power logic control signal, in order to make the short-circuit detection subcircuit work continuously, a sampling circuit is set, so that when the bandgap reference circuit works, the sampling circuit collects the reference voltage provided by the bandgap reference circuit and saves it, and when the bandgap reference circuit stops working, the sampling circuit provides the reference voltage for the short-circuit detection subcircuit, so that the short-circuit detection subcircuit can work normally.

[0015] Optionally, the low-power logic control circuit is communicatively connected to the sampling circuit to control the sampling circuit to operate periodically.

[0016] By sampling the above technical solution, the purpose of controlling the periodic operation of the sampling circuit through a low-power logic control signal is to further reduce the battery power consumed by the battery protection chip when protecting the battery.

[0017] Optionally, the low-power logic control circuit includes a low-power oscillator and a low-power control logic sub-circuit; the low-power oscillator is communicatively connected to the low-power control logic sub-circuit; the low-power control logic sub-circuit is communicatively connected to the voltage detection circuit, the overcurrent detection sub-circuit, the bandgap reference circuit and the sampling circuit respectively.

[0018] By adopting the above technical solution, the low-power control logic sub-circuit generates a low-power logic control signal, and the low-power oscillator enables the low-power logic control signal to be output periodically.

[0019] In a second aspect, the present application provides a battery protection method, which adopts the following technical solution:

[0020] A battery protection method comprises the following steps:

[0021] Periodically obtain the voltage value at both ends of the battery;

[0022] Periodically obtaining a first current value of charging or discharging the battery;

[0023] Compare the voltage value with a maximum voltage threshold and a minimum voltage threshold, and if the voltage value is greater than the maximum voltage threshold, or the voltage value is less than the minimum voltage threshold, output a voltage abnormality signal;

[0024] Comparing the first current value with a preset overcurrent threshold, and outputting a first current abnormality signal if the current value is greater than the overcurrent threshold;

[0025] Based on the abnormal voltage signal or the first abnormal current signal, the charging or discharging circuit of the battery is controlled to be disconnected.

[0026] By adopting the above technical solution, by periodically obtaining the voltage value of the voltage at both ends of the battery and the first current value of the battery charging or discharging, it is determined whether the voltage at both ends of the battery and the current of the battery charging or discharging are abnormal, thereby reducing the battery power consumed when protecting the battery.

[0027] Optionally, the battery protection method further includes:

[0028] Continuously obtaining a second current value of battery discharge;

[0029] Comparing the second current value with a preset short-circuit current threshold, and outputting a second current abnormality signal if the second current value is greater than the short-circuit current threshold;

[0030] Based on the second current abnormality signal, the discharge circuit of the battery is controlled to be disconnected.

[0031] By adopting the above technical solution, by continuously acquiring the second current value and comparing the second current value with the short-circuit current threshold, it can be ensured that the short-circuit state in the battery discharge loop can be detected quickly enough, thereby protecting the battery from damage.

[0032] Optionally, based on the abnormal voltage signal or the first abnormal current signal, the steps before controlling the battery charging or discharging circuit to be disconnected include:

[0033] Compare the duration of the abnormal voltage signal with a preset first time threshold, and if the duration of the abnormal voltage signal is greater than the first time threshold, control the charging or discharging circuit of the battery to be disconnected;

[0034] The duration of the first abnormal current signal is compared with a preset second time threshold. If the duration of the first abnormal current signal is greater than the second time threshold, the charging or discharging circuit of the battery is controlled to be disconnected.

[0035] By adopting the above technical solution, the duration of the voltage abnormality signal is compared with the first time threshold, and the duration of the first current abnormality signal is compared with the second time threshold. The purpose is that when controlling the battery charging or discharging circuit to be turned on, a transient large current or voltage may be generated in the battery charging or discharging circuit. Therefore, in order to improve the accuracy of battery protection, it is necessary to judge the duration of the voltage abnormality signal and the first current abnormality signal.

[0036] Optionally, based on the second abnormal current signal, the steps before controlling the battery discharge circuit to be disconnected include:

[0037] Compare the duration of the second abnormal current signal with a preset third time threshold, and if the duration of the second abnormal current signal is greater than the third time threshold, control the discharge circuit of the battery to be disconnected;

[0038] The third time threshold is smaller than the second time threshold.

[0039] By adopting the above technical solution, when the discharge circuit of the battery is short-circuited, an excessive short-circuit current will be generated. Therefore, if the preset third time threshold is longer than the second time threshold, the short-circuit current will last longer, thereby causing damage to the battery. Therefore, when it is detected that the second current value is greater than the short-circuit current threshold, the battery discharge circuit needs to be disconnected quickly.

[0040] In summary, the present application includes at least one of the following beneficial technical effects:

[0041] By setting up a low-power logic control circuit, the low-power logic control circuit controls the voltage detection circuit and the overcurrent detection subcircuit to work periodically, and the voltage detection circuit and the overcurrent detection subcircuit do not need to work continuously, thereby reducing the battery power consumed by the battery protection chip when protecting the battery, thereby increasing the battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a structural block diagram of a battery protection chip in the related art.

[0043] Figure 2 It is a structural block diagram of the battery protection circuit of the present application.

[0044] Figure 3 It is a schematic diagram of a low-power logic control signal.

[0045] Figure 4 This is a flowchart of determining whether the voltage is abnormal in a battery protection method.

[0046] Figure 5 It is a flowchart of judging whether the current is overcurrent in the battery protection method.

[0047] Figure 6 It is a flowchart of determining whether a battery charging or discharging circuit is short-circuited in a battery protection method.

[0048] Explanation of the reference numerals: 110, voltage detection circuit; 120, bandgap reference circuit; 130, drive circuit; 140, current detection circuit; 141, overcurrent detection subcircuit; 142, short-circuit detection subcircuit; 150, low-power logic control circuit; 151, low-power oscillator; 152, low-power control logic subcircuit; 160, sampling circuit. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] The following is combined with Figure 1-6 This application is described in further detail.

[0051] Reference Figure 1 In the related art, the lithium battery protection chip includes a voltage detection circuit 110, a bandgap reference circuit 120, a current detection circuit 140, a drive circuit 130 and a power switch S.

[0052] The voltage detection circuit 110 is connected to the VDD terminal and the drive circuit 130 respectively; the drive circuit 130 is connected to the gate of the power switch S; the source of the power switch S is connected to the GND terminal, the drain is connected to the VM terminal, and it is connected in series in the battery charging and discharging circuit; the bandgap reference circuit 120 is respectively connected to the VDD terminal, the voltage detection circuit 110 and the current detection circuit 140; the current detection circuit 140 is respectively connected to the VDD terminal and the drive circuit 130; the positive electrode of the battery is connected to the VDD terminal, and the negative electrode is connected to the GND terminal; the load or charger is connected between the VDD terminal and the VM terminal.

[0053] When the battery is charging or discharging, the voltage detection circuit 110 detects the voltage at both ends of the battery in real time, and compares the detected voltage value with the maximum voltage threshold and the minimum voltage threshold provided by the bandgap reference circuit 120. If the voltage value is higher than the maximum voltage threshold or lower than the minimum voltage threshold, the drive circuit 130 controls the power switch S to be disconnected, thereby disconnecting the battery charging or discharging circuit; or, the current detection circuit 140 detects the charging or discharging current of the battery in real time, and compares the detected current value with the reference current value provided by the bandgap reference circuit 120. If the current value is greater than the reference current value, the drive circuit 130 controls the power switch S to be disconnected, thereby disconnecting the battery charging or discharging circuit; thereby protecting the battery.

[0054] Since the battery protection chip is in real-time working state, the battery power will be consumed when its internal circuit is working; therefore, in order to reduce the power consumption while the battery is protected;

[0055] Reference Figure 2An embodiment of the present application provides a battery protection circuit, which may include a low-power logic control circuit 150, which is communicatively connected to the voltage detection circuit 110. The current detection circuit 140 includes an overcurrent detection subcircuit 141, and the low-power logic control circuit 150 is also communicatively connected to the overcurrent detection subcircuit 141.

[0056] When protecting the battery from charging or discharging, the low-power logic control circuit 150 will periodically output a low-power logic control signal, which controls the voltage detection circuit 110 and the overcurrent detection subcircuit 141 to work periodically, thereby reducing the battery power consumed when the battery protection chip is protecting the battery.

[0057] In order to further reduce the amount of power consumed by the battery, the low power consumption logic control circuit 150 is also connected to the bandgap reference circuit 120 for controlling the bandgap reference circuit 120 to operate periodically.

[0058] In order to ensure that the battery protection circuit can detect the short-circuit state of the battery discharge circuit quickly enough, the current detection circuit 140 also includes a short-circuit detection subcircuit 142, and the short-circuit detection subcircuit 142 works continuously; the bandgap reference circuit 120 provides a reference voltage for the short-circuit detection subcircuit 142 so that the short-circuit detection subcircuit 142 can work continuously.

[0059] However, since the bandgap reference circuit 120 works periodically, in order to make the short-circuit detection subcircuit 142 work continuously, the battery protection circuit further includes a sampling circuit 160, and the sampling circuit 160 is respectively connected to the bandgap reference circuit 120 and the short-circuit detection subcircuit 142. In addition, the low-power logic control circuit 150 is connected to the sampling circuit 160 to control the sampling circuit 160 to work periodically.

[0060] When the bandgap reference circuit 120 is working, the sampling circuit 160 is working, and the sampling circuit 160 samples and stores the reference voltage provided by the bandgap reference circuit 120 . When the bandgap reference circuit 120 is not working, the sampling circuit 160 provides a reference voltage for the short circuit detection subcircuit 142 .

[0061] The low power logic control circuit 150 includes a low power oscillator 151 and a low power control logic sub-circuit 152; the low power oscillator 151 is connected to the low power control logic sub-circuit 152 in communication, so that the low power control logic sub-circuit 152 periodically outputs a low power logic control signal. Low power consumption means that the voltage is within the range of 2.8V-4.2V during operation.

[0062] In addition, refer to Figure 3 , a low-power logic control signal construction method is as follows:

[0063] The voltage detection circuit 110, the overcurrent detection subcircuit 141, the bandgap reference circuit 120 and the sampling circuit 160 are operated as a high level, and the high level is valid; that is, when the bandgap reference circuit 120 is working, the bandgap reference enable signal is a high level; when the overcurrent detection subcircuit 141 and the voltage detection module are working, the detection enable signal is a high level; when the sampling circuit 160 is working, the sampling enable signal is a high level. In addition, in other implementations, the circuit working state can also be set as a low level, and the low level is valid. The specific setting can be made by humans, as long as the low-power logic control signal controls the required circuit to work periodically.

[0064] The low power logic control signal is set to 20ms as a control cycle, wherein the bandgap reference circuit 120 works for 4ms within 20ms; the overcurrent detection subcircuit 141, the voltage detection circuit 110 and the sampling circuit 160 work simultaneously, and after the bandgap reference circuit 120 works for 2ms, the overcurrent detection subcircuit 141, the voltage detection circuit 110 and the sampling circuit 160 work again; the bandgap reference circuit 120 stops working after working for 4ms, and the overcurrent detection subcircuit 141, the voltage detection circuit 110 and the sampling circuit 160 stop working 5us earlier than the bandgap reference circuit 120.

[0065] The purpose of turning on the bandgap reference circuit 120 in advance is to ensure that the reference voltage and reference current provided by the bandgap reference circuit 120 have been correctly established when it is working; the purpose of turning off the bandgap reference circuit 120 last is to prevent the occurrence of random sequence and cause unexpected situations, thereby improving the overall stability of the battery protection circuit.

[0066] In addition, if the voltage across the battery or the charging or discharging current of the battery is in an abnormal state, the low-power logic control signal controls the bandgap reference circuit 120, the overcurrent detection subcircuit 141, the voltage detection circuit 110 and the sampling circuit 160 to remain in the on state, and at this time the drive circuit 130 controls the power switch S to be disconnected until the battery protection circuit returns to normal.

[0067] The principle of this embodiment is:

[0068] When the battery is being charged or discharged, the short-circuit detection subcircuit 142, the drive circuit 130, the low-power oscillator 151 and the low-power control logic subcircuit 152 are turned on. Then, the low-power control logic subcircuit 152 first controls the bandgap reference circuit 120 to be turned on. After the bandgap reference circuit 120 is turned on for 2ms, the voltage detection circuit 110, the overcurrent detection subcircuit 141 and the sampling circuit 160 are controlled to be turned on at the same time.

[0069] The voltage detection circuit 110 detects the voltage at both ends of the battery, the overcurrent detection subcircuit 141 detects the current in the battery charging or discharging circuit, and the short-circuit detection subcircuit 142 detects the current in the battery discharging circuit. If the voltage and / or current are normal, the low-power control logic subcircuit 152 controls the bandgap reference circuit 120 to be turned on and then turned off after 4ms, and controls the voltage detection circuit 110, the overcurrent detection subcircuit 141 and the sampling circuit 160 to be turned off 5us earlier than the bandgap reference circuit 120; after 20ms, the low-power control logic subcircuit 152 turns on the bandgap reference circuit 120 again, so that the bandgap reference circuit 120, the voltage detection circuit 110, the overcurrent detection subcircuit 141 and the sampling circuit 160 work periodically;

[0070] If the voltage detection circuit 110 detects that the voltage value across the battery is greater than the highest voltage threshold or less than the lowest voltage threshold, or the overcurrent detection subcircuit 141 detects that the current value of the battery charging or discharging is greater than the overcurrent threshold, or the short-circuit detection subcircuit 142 detects that the current value of the battery discharging is greater than the short-circuit current threshold, the low-power control logic subcircuit 152 controls the bandgap reference circuit 120, the voltage detection circuit 110, the overcurrent detection subcircuit 141 and the sampling circuit 160 to keep working, so that the drive circuit 130 controls the power switch S to disconnect, so that the charging or discharging circuit of the battery is disconnected until the battery protection circuit returns to normal.

[0071] Reference Figure 4 and Figure 5 Based on the embodiment of the battery protection circuit, the second embodiment of the present application further provides a battery protection method, which, as an implementation of the battery protection method, may include the following steps S101-S106:

[0072] S101, periodically obtaining voltage values ​​at both ends of the battery;

[0073] The voltage detection circuit 110 is controlled by the low power control logic sub-circuit 152 to periodically obtain the voltage values ​​at both ends of the battery.

[0074] S102, periodically obtaining a first current value of charging or discharging the battery;

[0075] The low power control logic sub-circuit 152 controls the over-current detection sub-circuit 141 to periodically obtain the first current value of the battery charging or discharging.

[0076] S103, comparing the voltage value with the highest voltage threshold and the lowest voltage threshold, if the voltage value is greater than the highest voltage threshold, or the voltage value is less than the lowest voltage threshold, outputting a voltage abnormality signal;

[0077] For example, the maximum voltage value is set to 4.28V, and the minimum voltage value is set to 2.8V; if the voltage detection circuit 110 detects that the battery voltage is 4.3V, 4.3V>4.28V, or when the voltage detection circuit 110 detects that the battery voltage is 2.6V, 2.6V<2.8V, then the voltage detection circuit 110 will output a voltage abnormality signal.

[0078] S104, comparing the duration of the abnormal voltage signal with a preset first time threshold, and if the duration of the abnormal voltage signal is greater than the first time threshold, controlling the charging or discharging circuit of the battery to be disconnected;

[0079] After receiving the abnormal voltage signal, the driving circuit 130 determines the duration of the abnormal voltage signal. If the duration of the abnormal voltage signal is greater than the first time threshold, the power switch S is controlled to be disconnected, thereby controlling the battery charging or discharging circuit to be disconnected.

[0080] For example, the first time threshold is set to 200 ms. If the voltage abnormality signal continues to exist within 300 ms, 300 ms>200 ms. Therefore, the driving circuit 130 controls the power switch S to be turned off.

[0081] S105, comparing the first current value with a preset overcurrent threshold, and if the current value is greater than the overcurrent threshold, outputting a first current abnormality signal;

[0082] The over-current threshold is a reference current provided by the bandgap reference circuit 120 .

[0083] For example, the overcurrent threshold is set to 2A; if the overcurrent detection subcircuit 141 detects that the current value of the battery charging or discharging is 3A, 3A>2A, then the overcurrent detection subcircuit 141 will output a first current abnormality signal.

[0084] S106, comparing the duration of the first abnormal current signal with a preset second time threshold, and if the duration of the first abnormal current signal is greater than the second time threshold, controlling the charging or discharging circuit of the battery to be disconnected;

[0085] After receiving the first abnormal current signal, the driving circuit 130 determines the duration of the first abnormal current signal. If the duration of the first abnormal current signal is greater than the second time threshold, the power switch S is controlled to be disconnected, thereby controlling the battery charging or discharging circuit to be disconnected.

[0086] For example, the second time threshold is set to 50 ms. If the first current abnormality signal continues to exist within 60 ms, 60 ms>50 ms. Therefore, the driving circuit 130 controls the power switch S to be disconnected.

[0087] Reference Figure 6In order to ensure that the short circuit state in the charging or discharging circuit of the battery can be detected quickly enough to protect the battery from damage; the battery protection method may also include steps S201-S203:

[0088] S201, continuously obtaining a second current value of battery discharge;

[0089] The short circuit detection sub-circuit 142 keeps working.

[0090] S202, comparing the second current value with a preset short-circuit current threshold, and outputting a second current abnormality signal if the second current value is greater than the short-circuit current threshold;

[0091] For example, the short-circuit current threshold is set to 4A; if the short-circuit detection subcircuit 142 detects that the current value of the battery discharge current is 5A, 5A>4A, then the short-circuit detection subcircuit 142 will output a second current abnormality signal;

[0092] S203, comparing the duration of the second abnormal current signal with a preset third time threshold, and if the duration of the second abnormal current signal is greater than the third time threshold, controlling the battery discharge circuit to be disconnected;

[0093] After receiving the second abnormal current signal, the driving circuit 130 determines the duration of the second abnormal current signal. If the duration of the second abnormal current signal is greater than the third time threshold, the power switch S is controlled to be disconnected, thereby controlling the battery discharge circuit to be disconnected. It should be noted that the third time threshold is less than the second time threshold.

[0094] For example, the third time threshold is set to 200us. If the second current abnormality signal continues to exist within 300us, and 300us>200us, the driving circuit 130 controls the power switch S to be turned off.

[0095] The implementation principle of this embodiment is:

[0096] When the battery is charging or discharging, the voltage across the battery is periodically obtained, the first current value of the battery charging or discharging is periodically obtained, and the second current value of the battery charging or discharging is continuously obtained;

[0097] Compare the voltage value with the highest voltage threshold and the lowest voltage threshold. If the voltage value is greater than the highest voltage threshold or less than the lowest voltage threshold, output a voltage abnormality signal. If the duration of the voltage abnormality signal is greater than the first time threshold, control the battery charging or discharging circuit to be disconnected.

[0098] Compare the first current value with the overcurrent threshold, and if the first current value is greater than the overcurrent threshold, output a first current abnormality signal; if the duration of the first current abnormality signal is greater than a second time threshold, control the battery charging or discharging circuit to be disconnected;

[0099] The second current value is compared with the short-circuit current threshold. If the second current value is greater than the short-circuit current threshold, a second current abnormality signal is output; if the duration of the second current abnormality signal is greater than a third time threshold, the battery discharge circuit is controlled to be disconnected.

[0100] The above are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application in sequence. Any feature disclosed in this specification (including the abstract and drawings), unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

Claims

1. A battery protection circuit, comprising a voltage detection circuit (110) and a current detection circuit (140), characterized in that: It also includes a low-power logic control circuit (150), and the current detection circuit (140) includes an overcurrent detection subcircuit (141); the low-power logic control circuit (150) is respectively connected to the voltage detection circuit (110) and the overcurrent detection subcircuit (141) for communication, and is used to periodically output a low-power logic control signal to control the voltage detection circuit (110) and the overcurrent detection subcircuit (141) to operate periodically; The battery protection circuit further comprises a bandgap reference circuit (120), and the low-power consumption logic control circuit (150) is communicatively connected with the bandgap reference circuit (120) and is used to control the bandgap reference circuit (120) to operate periodically; The current detection circuit (140) includes a short-circuit detection subcircuit (142), and the battery protection circuit also includes a sampling circuit (160). The sampling circuit (160) is respectively connected to the bandgap reference circuit (120) and the short-circuit detection subcircuit (142) for communication and is used to collect a reference voltage provided by the bandgap reference circuit (120) for the short-circuit detection subcircuit (142) to operate normally; wherein the short-circuit detection subcircuit (142) operates continuously.

2. The battery protection circuit according to claim 1, characterized in that: The low-power consumption logic control circuit (150) is communicatively connected to the sampling circuit (160) and is used to control the sampling circuit (160) to operate periodically.

3. The battery protection circuit according to any one of claims 1-2, characterized in that: The low-power logic control circuit (150) comprises a low-power oscillator (151) and a low-power control logic sub-circuit (152); the low-power oscillator (151) is communicatively connected to the low-power control logic sub-circuit (152); and the low-power control logic sub-circuit (152) is communicatively connected to the voltage detection circuit (110), the overcurrent detection sub-circuit (141), the bandgap reference circuit (120), and the sampling circuit (160), respectively.

4. A battery protection method, characterized in that: Based on the battery protection circuit as described in any one of claims 1 to 3; the battery protection method comprises the following steps: Periodically obtain the voltage value at both ends of the battery; Periodically obtaining a first current value of charging or discharging the battery; Compare the voltage value with a maximum voltage threshold and a minimum voltage threshold, and if the voltage value is greater than the maximum voltage threshold, or the voltage value is less than the minimum voltage threshold, output a voltage abnormality signal; Comparing the first current value with a preset overcurrent threshold, and outputting a first current abnormality signal if the current value is greater than the overcurrent threshold; Based on the abnormal voltage signal or the first abnormal current signal, the charging or discharging circuit of the battery is controlled to be disconnected.

5. The battery protection method according to claim 4, characterized in that: The battery protection method further includes: Continuously obtaining a second current value of battery discharge; Comparing the second current value with a preset short-circuit current threshold, and outputting a second current abnormality signal if the second current value is greater than the short-circuit current threshold; Based on the second current abnormality signal, the discharge circuit of the battery is controlled to be disconnected.

6. The battery protection method according to claim 4, characterized in that: Based on the abnormal voltage signal or the first abnormal current signal, the steps before controlling the battery charging or discharging circuit to be disconnected include: Compare the duration of the abnormal voltage signal with a preset first time threshold, and if the duration of the abnormal voltage signal is greater than the first time threshold, control the charging or discharging circuit of the battery to be disconnected; The duration of the first abnormal current signal is compared with a preset second time threshold. If the duration of the first abnormal current signal is greater than the second time threshold, the charging or discharging circuit of the battery is controlled to be disconnected.

7. The battery protection method according to claim 5, characterized in that: Based on the second abnormal current signal, the steps before controlling the battery discharge circuit to be disconnected include: Compare the duration of the second abnormal current signal with a preset third time threshold, and if the duration of the second abnormal current signal is greater than the third time threshold, control the discharge circuit of the battery to be disconnected; The third time threshold is smaller than the second time threshold.

Images