Circuit and device for intelligent overcharge protection and switching

Abstract

This application provides a circuit and device for intelligent switching to prevent overcharge. The circuit includes an AC-DC voltage conversion unit, a normally-on identification unit, and an overcharge prevention unit. The normally-on identification unit obtains the real-time charging voltage from the AC-DC voltage conversion unit and determines whether the device to be charged is in a normally-on state or an overcharge prevention state based on the real-time charging voltage. The overcharge prevention unit obtains the real-time charging current from the AC-DC voltage conversion unit. In the normally-on state, it controls the AC-DC voltage conversion unit to charge the device to be charged based on a first signal. In the overcharge prevention state, it controls the AC-DC voltage conversion unit to charge the device to be charged based on a second signal and the real-time charging current, or controls the AC-DC voltage conversion unit to stop charging the device to be charged. This solves the problem that existing solutions cannot identify the device to be charged.

Description

Technical Field

[0001] This application relates to the field of charging technology, and more specifically, to a circuit and device for intelligent switching to prevent overcharging. Background Technology

[0002] In existing technologies, when charging devices with low power consumption, such as Bluetooth headsets and smartwatches, the charging current is relatively small, causing them to enter overcharge protection mode prematurely, resulting in incomplete charging. If a mobile phone is set to battery health mode and stops charging at 80%, it will also enter overcharge protection mode, causing the device to not fully charge. Furthermore, some charging devices do not require overcharge protection, such as laptops. The standby mode charging current is small, which may cause the laptop to enter overcharge protection mode, resulting in frequent battery depletion. Therefore, laptops do not need overcharge protection, but existing solutions cannot solve the above problems. Summary of the Invention

[0003] The main objective of this application is to provide a circuit and device for intelligent switching to prevent overcharging, in order to solve the problem that existing solutions cannot identify the device to be charged.

[0004] To achieve the above objectives, according to one aspect of this application, a circuit for intelligent overcharge protection is provided. This circuit includes an AC / DC voltage conversion unit, a constant-on identification unit, and an overcharge protection unit. The AC / DC voltage conversion unit is electrically connected to the device to be charged. The constant-on identification unit is electrically connected to the AC / DC voltage conversion unit and is used to obtain a real-time charging voltage from the AC / DC voltage conversion unit. Based on the real-time charging voltage, it determines whether the device to be charged is in a constant-on state or an overcharge protection state. When the device to be charged is in the constant-on state, the constant-on identification unit outputs a first signal. When the device to be charged is in the constant-on state, the constant-on identification unit outputs a first signal. In the overcharge protection state, the normally open identification unit outputs a second signal. The overcharge protection unit is electrically connected to both the AC-DC voltage conversion unit and the normally open identification unit, and is used to obtain the real-time charging current of the AC-DC voltage conversion unit. In the normally open state, based on the first signal, the AC-DC voltage conversion unit is controlled to charge the device to be charged. In the overcharge protection state, based on the second signal and the real-time charging current, the AC-DC voltage conversion unit is controlled to charge the device to be charged, or the AC-DC voltage conversion unit is controlled to stop charging the device to be charged.

[0005] Furthermore, the constant-current identification unit includes a first comparator, which has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the first comparator is electrically connected to the AC-DC voltage conversion unit. The real-time charging voltage is input to the first input terminal of the first comparator. The second input terminal of the first comparator is used to input a preset voltage. The output terminal of the first comparator outputs a first comparison result, which is used to characterize the magnitude relationship between the real-time charging voltage and the preset voltage.

[0006] Furthermore, the constant-current identification unit also includes a first controller, which has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the first controller is electrically connected to the AC-DC voltage conversion unit, and the real-time charging voltage is input to the first terminal of the first controller. The second terminal of the first controller is electrically connected to the first input terminal of the first comparator, the third terminal of the first controller is electrically connected to the output terminal of the first comparator, and the fourth terminal of the first controller is electrically connected to the overcharge protection unit, for outputting the first signal or the second signal.

[0007] Furthermore, the overcharge protection unit includes a second comparator, which has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the second comparator is electrically connected to the AC-DC voltage conversion unit. The real-time charging current is input to the first input terminal of the second comparator. The second input terminal of the second comparator is used to input a first preset current. The output terminal of the second comparator outputs a second comparison result, which is used to characterize the magnitude relationship between the real-time charging current and the first preset current.

[0008] Furthermore, the overcharge protection unit also includes a second controller. The second controller has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the second controller is electrically connected to the normally connected identification unit and is used to receive the first signal or the second signal. The second terminal of the second controller is electrically connected to the AC-DC voltage conversion unit. The real-time charging current is input to the second terminal of the second controller. The third terminal of the second controller is electrically connected to the first input terminal of the second comparator. The fourth terminal of the second controller is electrically connected to the output terminal of the second comparator. The second controller is used to control the AC-DC voltage conversion unit to charge the device to be charged when receiving the first signal, and to transmit the real-time charging current to the second comparator when receiving the second signal, and to control the AC-DC voltage conversion unit to charge the device to be charged or to control the AC-DC voltage conversion unit to stop charging the device to be charged according to the second comparison result.

[0009] Furthermore, the overcharge protection unit also includes a third comparator and a fourth comparator. The third comparator has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the third comparator is electrically connected to the fifth terminal of the second controller. When the second comparison result indicates that the real-time charging current is less than the first preset current, the fifth terminal of the second controller outputs a third signal, which is the real-time charging current. The second input terminal of the third comparator is used to input the second preset current. The output terminal of the third comparator is electrically connected to the sixth terminal of the second controller, and the output terminal of the third comparator outputs a third comparison result. The third comparison result is used to characterize the difference between the real-time charging current and the second preset current. The fourth comparator has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the fourth comparator is electrically connected to the seventh terminal of the second controller. When the second comparison result indicates that the real-time charging current is less than the first preset current, the seventh terminal of the second controller outputs a fourth signal, which is the real-time charging current. The first input terminal of the fourth comparator is used to input a third preset current, which is less than the second preset current. The output terminal of the fourth comparator is electrically connected to the eighth terminal of the second controller, and the output terminal of the fourth comparator outputs a fourth comparison result. The fourth comparison result is used to characterize the relationship between the real-time charging current and the third preset current.

[0010] Furthermore, the second controller is also configured to perform the following steps: when the first comparison result indicates that the real-time charging voltage is greater than or equal to a preset voltage, controlling the AC-DC voltage conversion unit to charge the device to be charged; when the first comparison result indicates that the real-time charging voltage is less than the preset voltage, sending the real-time charging current to the first input terminal of the second comparator; when the second comparison result indicates that the real-time charging current is greater than or equal to a first preset current, controlling the AC-DC voltage conversion unit to charge the device to be charged; and when the second comparison result indicates that the real-time charging current is less than the first preset current, sending the real-time charging current to the first output terminal of the second comparator. The third comparator's first input terminal; when the third comparison result indicates that the real-time charging current is less than the second preset current, the AC-DC voltage conversion unit is controlled to stop charging the device to be charged; when the third comparison result indicates that the real-time charging current is greater than or equal to the second preset current, the AC-DC voltage conversion unit is controlled to charge the device to be charged; when the fourth comparison result indicates that the real-time charging current is less than the third preset current, the AC-DC voltage conversion unit is controlled to stop charging the device to be charged; when the fourth comparison result indicates that the real-time charging current is greater than or equal to the third preset current, the AC-DC voltage conversion unit is controlled to charge the device to be charged.

[0011] Furthermore, the overcharge protection unit also includes a field-effect transistor (FET). The gate of the FET is electrically connected to the first terminal of the second controller, the ninth terminal of the second controller, the AC-DC voltage conversion unit, and the normally-on identification unit, respectively. The FET has a first turn-off current and a second turn-off current, and the first turn-off current is greater than the second turn-off current. Based on the first comparison result, the second comparison result, the third comparison result, and the fourth comparison result, the second controller outputs a fifth signal at the ninth terminal of the second controller. The fifth signal is a current signal used to control the turn-off of the FET, so as to realize whether the AC-DC voltage conversion unit charges the device to be charged.

[0012] Furthermore, the circuit also includes a power depletion detection unit, which is electrically connected to the tenth terminal of the second controller. The power depletion detection unit is used to output a sixth signal every predetermined time period when the first comparison result indicates that the real-time charging voltage is less than a preset voltage. The sixth signal enables the second controller to control the AC-DC voltage conversion module to charge the device to be charged.

[0013] According to another aspect of this application, an overcharge protection intelligent switching device is provided, the device comprising the overcharge protection intelligent switching circuit described in any of the above.

[0014] By applying the technical solution of this application, a device that needs continuous charging (e.g., a laptop) or a device that needs overcharge protection (e.g., a mobile phone) is first identified by a constant-current identification unit. When a device that needs continuous charging is identified, a first signal is generated and sent to an overcharge protection unit. The overcharge protection unit controls an AC-DC voltage conversion unit to charge the device based on the first signal, thus achieving the purpose of continuously charging the device that needs continuous charging. When a device that needs overcharge protection is identified, a second signal is generated and sent to the overcharge protection unit. The overcharge protection unit controls the AC-DC voltage conversion unit to charge the device based on the second signal and the real-time charging current obtained by the overcharge protection unit, or controls the AC-DC voltage conversion unit to stop charging the device, so as to ensure that the device that needs overcharge protection is fully charged. This achieves the purpose of identifying the device to be charged, thereby solving the problem that existing solutions cannot identify the device to be charged. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0016] Figure 1 A schematic diagram of an overcharge protection intelligent switching circuit according to an embodiment of this application is shown.

[0017] The above figures include the following reference numerals:

[0018] 10. AC / DC voltage conversion unit; 20. Normally active identification unit; 21. First comparator; 22. First controller; 30. Overcharge protection unit; 31. Second comparator; 32. Second controller; 33. Third comparator; 34. Fourth comparator; 35. Field-effect transistor; 40. Low-voltage detection unit. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0023] As described in the background section, in the prior art, when charging devices with low power consumption, such as Bluetooth headsets and smartwatches, the charging current is relatively small, causing them to enter the overcharge protection mode prematurely, resulting in the devices not being fully charged. If a mobile phone is set to battery health mode and stops charging at 80%, it will also enter the overcharge protection mode, resulting in the device not being fully charged. Furthermore, some charging devices do not require overcharge protection, such as laptops. The standby mode charging current is small, which may cause the laptop to enter the overcharge protection mode, resulting in the laptop frequently running out of power. Therefore, laptops do not need overcharge protection. However, the existing solutions cannot solve the above problems. Therefore, in order to solve the problem that the existing solutions cannot identify the device to be charged, this application provides a circuit and device for intelligent switching of overcharge protection.

[0024] According to embodiments of this application, a circuit for intelligent switching to prevent overcharging is provided, such as... Figure 1As shown, the circuit includes an AC / DC voltage conversion unit 10, a constant-on identification unit 20, and an overcharge protection unit 30. The AC / DC voltage conversion unit 10 is electrically connected to the device to be charged (via the VOUT terminal). The constant-on identification unit 20 is electrically connected to the AC / DC voltage conversion unit 10 and is used to obtain the real-time charging voltage from the AC / DC voltage conversion unit 10. Based on the real-time charging voltage, it determines whether the device to be charged is in a constant-on state or an overcharge protection state. When the device to be charged is in the constant-on state, the constant-on identification unit 20 outputs a first signal. When the device to be charged is in the overcharge protection state, the constant-on identification unit 20 outputs a first signal. The normally-on identification unit 20 outputs a second signal; the overcharge prevention unit 30 is electrically connected to the AC-DC voltage conversion unit 10 and the normally-on identification unit 20 respectively, and is used to obtain the real-time charging current of the AC-DC voltage conversion unit 10 from the AC-DC voltage conversion unit 10. In the normally-on state, according to the first signal, the AC-DC voltage conversion unit 10 is controlled to charge the device to be charged. In the overcharge prevention state, according to the second signal and the real-time charging current, the AC-DC voltage conversion unit 10 is controlled to charge the device to be charged, or the AC-DC voltage conversion unit 10 is controlled to stop charging the device to be charged.

[0025] The circuit described above first identifies devices that require continuous charging (e.g., laptops) or devices requiring overcharge protection (e.g., mobile phones) through a constant-current identification unit. When a device requiring continuous charging is identified, a first signal is generated and sent to the overcharge protection unit. The overcharge protection unit then controls an AC / DC voltage conversion unit to charge the device based on the first signal, thus achieving continuous charging of the device requiring continuous charging. When a device requiring overcharge protection is identified, a second signal is generated and sent to the overcharge protection unit. The overcharge protection unit, based on the second signal and the real-time charging current obtained by the unit, controls the AC / DC voltage conversion unit to charge the device or stops charging the device, ensuring that the device requiring overcharge protection is fully charged. This achieves the goal of identifying the device to be charged, thus solving the problem that existing solutions cannot identify the device to be charged.

[0026] According to one embodiment of this application, such as Figure 1As shown, the aforementioned constant-current identification unit 20 includes a first comparator 21, which has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the first comparator 21 is electrically connected to the aforementioned AC-DC voltage conversion unit 10. The real-time charging voltage is input to the first input terminal of the first comparator 21. The second input terminal of the first comparator 21 is used to input a preset voltage. The output terminal of the first comparator 21 outputs a first comparison result. The first comparison result is used to characterize the magnitude relationship between the real-time charging voltage and the preset voltage, thereby achieving the purpose of determining the magnitude relationship between the real-time charging voltage and the preset voltage.

[0027] According to one embodiment of this application, such as Figure 1 As shown, the aforementioned constant-current identification unit 20 further includes a first controller 22, which has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the first controller 22 is electrically connected to the aforementioned AC / DC voltage conversion unit 10. The aforementioned real-time charging voltage is input to the first terminal of the first controller 22. The second terminal of the first controller 22 is electrically connected to the first input terminal of the aforementioned first comparator 21. The third terminal of the first controller 22 is electrically connected to the output terminal of the aforementioned first comparator 21. The fourth terminal of the first controller 22 is electrically connected to the aforementioned overcharge protection unit 30, and is used to output the aforementioned first signal or the aforementioned second signal. Based on the result of the relationship between the magnitude of the aforementioned real-time charging voltage and the aforementioned preset voltage, the type of the device to be charged is determined, that is, whether the device to be charged is a device that needs to be continuously charged (e.g., a laptop) or a device that needs to be protected against overcharge (e.g., a mobile phone).

[0028] Specifically, for example, charging devices such as mobile phones, Bluetooth headsets, and tablets require overcharge protection, as their charging voltage is between 3.3 and 15V. However, laptops do not require overcharge protection, as their charging voltage is generally between 19 and 20V. By setting the threshold at 18V, it becomes easier to distinguish between them. When the real-time charging voltage is greater than or equal to 18V, the overcharge protection function is disabled. That is, the first controller generates a first signal and outputs the first signal from the fourth terminal of the first controller, so that the overcharge protection unit controls the AC-DC voltage conversion unit to charge the device to be charged according to the first signal, thus achieving the purpose of continuously charging the device that needs to be charged. When the real-time charging voltage is less than 18V, the overcharge protection function is retained. That is, the first controller generates a second signal and outputs the second signal from the fourth terminal of the first controller, so that the overcharge protection unit controls the AC-DC voltage conversion unit to charge the device to be charged, or controls the AC-DC voltage conversion unit to stop charging the device to be charged, according to the second signal and the real-time charging current obtained by the overcharge protection unit, to ensure that the device requiring overcharge protection is fully charged.

[0029] According to one embodiment of this application, such as Figure 1 As shown, the overcharge protection unit 30 includes a second comparator 31, which has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the second comparator 31 is electrically connected to the AC-DC voltage conversion unit 10. The real-time charging current is input to the first input terminal of the second comparator 31. The second input terminal of the second comparator 31 is used to input a first preset current. The output terminal of the second comparator 31 outputs a second comparison result. The second comparison result is used to characterize the relationship between the real-time charging current and the first preset current, thereby achieving the purpose of determining the relationship between the real-time charging current and the first preset current.

[0030] According to one embodiment of this application, such as Figure 1 As shown, the overcharge protection unit 30 further includes a second controller 32, which has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the second controller 32 is electrically connected to the normally connected identification unit 20 and is used to receive the first signal or the second signal. The second terminal of the second controller 32 is electrically connected to the AC / DC voltage conversion unit 10, and the real-time charging current is input to the second terminal of the second controller 32. The third terminal of the second controller 32 is electrically connected to the first input terminal of the second comparator, and the fourth terminal of the second controller 32 is electrically connected to the output terminal of the second comparator. The second controller 32 is used to control the AC-DC voltage conversion unit 10 to charge the device to be charged when receiving the first signal, and to transmit the real-time charging current to the second comparator 31 when receiving the second signal, and to control the AC-DC voltage conversion unit 10 to charge the device to be charged or to control the AC-DC voltage conversion unit 10 to stop charging the device to be charged according to the second comparison result. This realizes that depending on the type of device to be charged, it can keep it constantly charged or ensure that the device to be charged is fully charged while preventing overcharging.

[0031] According to one embodiment of this application, such as Figure 1As shown, the overcharge protection unit 30 further includes a third comparator 33 and a fourth comparator 34. The third comparator 33 has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the third comparator 33 is electrically connected to the fifth terminal of the second controller 32. When the second comparison result indicates that the real-time charging current is less than the first preset current, the fifth terminal of the second controller 32 outputs a third signal, which is the real-time charging current. The second input terminal of the third comparator 33 is used to input the second preset current. The output terminal of the third comparator 33 is electrically connected to the sixth terminal of the second controller 32, and the output terminal of the third comparator 33 outputs a third comparison result. The third comparison result is used to characterize the real-time charging current and the second preset current. The fourth comparator 34 has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the fourth comparator 34 is electrically connected to the seventh terminal of the second controller 32. When the second comparison result indicates that the real-time charging current is less than the first preset current, the seventh terminal of the second controller 32 outputs a fourth signal, which is the real-time charging current. The first input terminal of the fourth comparator 34 is used to input a third preset current, which is less than the second preset current. The output terminal of the fourth comparator 34 is electrically connected to the eighth terminal of the second controller 32. The output terminal of the fourth comparator 34 outputs a fourth comparison result, which is used to characterize the relationship between the real-time charging current and the third preset current.

[0032] According to one embodiment of this application, the second controller is further configured to perform the following steps: when the first comparison result indicates that the real-time charging voltage is greater than or equal to a preset voltage, controlling the AC-DC voltage conversion unit to charge the device to be charged; when the first comparison result indicates that the real-time charging voltage is less than the preset voltage, sending the real-time charging current to the first input terminal of the second comparator; when the second comparison result indicates that the real-time charging current is greater than or equal to a first preset current, controlling the AC-DC voltage conversion unit to charge the device to be charged; and when the second comparison result indicates that the real-time charging current is less than the first preset current, sending the real-time charging current to the first input terminal of the second comparator respectively. The system includes an output terminal and a first input terminal of the third comparator. If the third comparison result indicates that the real-time charging current is less than the second preset current, the system controls the AC / DC voltage conversion unit to stop charging the device to be charged. If the third comparison result indicates that the real-time charging current is greater than or equal to the second preset current, the system controls the AC / DC voltage conversion unit to charge the device to be charged. If the fourth comparison result indicates that the real-time charging current is less than the third preset current, the system controls the AC / DC voltage conversion unit to stop charging the device to be charged. If the fourth comparison result indicates that the real-time charging current is greater than or equal to the third preset current, the system controls the AC / DC voltage conversion unit to charge the device to be charged.

[0033] Specifically, the first preset current is greater than both the second and third preset currents, with the second preset current being greater than the third preset current. For example, if the first preset current is set to 100mA, when the real-time charging current is greater than 100mA, the second controller identifies the charging mode of the device to be charged as the first current mode (i.e., a larger current) and controls the AC-DC voltage conversion unit to charge the device. When the real-time charging current is less than 100mA, the second controller identifies the charging mode of the device to be charged as the second current mode (i.e., a smaller current). Furthermore, if the third comparison result indicates that the real-time charging current is less than the second preset current, the second controller controls the AC-DC voltage conversion unit to stop charging the device. If the third comparison result indicates that the real-time charging current is greater than or equal to the second preset current, the second controller controls the AC-DC voltage conversion unit to charge the device, thereby ensuring that the charging process is performed correctly when the device is charged using the first current mode. During the process, the device to be charged is fully charged before charging stops (because the second preset current is greater than the third preset current; judging the magnitude of the second preset current and the real-time charging current is to ensure that the device to be charged can be fully charged under the first current mode). The second controller recognizes the charging mode of the device to be charged as the state of charging in the second current mode (i.e., a smaller current). If the fourth comparison result shows that the real-time charging current is less than the third preset current, the second controller controls the AC-DC voltage conversion unit to stop charging the device to be charged. If the fourth comparison result shows that the real-time charging current is greater than or equal to the third preset current, the second controller controls the AC-DC voltage conversion unit to charge the device to be charged. This ensures that the device to be charged is fully charged before charging stops during the process of charging the device to be charged in the second current mode (because the second preset current is greater than the third preset current; judging the magnitude of the third preset current and the real-time charging current is to ensure that the device to be charged can be fully charged under the second current mode).

[0034] According to one embodiment of this application, such as Figure 1As shown, the overcharge protection unit 30 further includes a field-effect transistor 35. The gate of the field-effect transistor 35 is electrically connected to the first terminal of the second controller 32, the ninth terminal of the second controller 32, the AC-DC voltage conversion unit 10, and the normally-on identification unit 20, respectively. It has a first turn-off current and a second turn-off current, and the first turn-off current is greater than the second turn-off current. The second controller outputs a fifth signal at the ninth terminal of the second controller based on the first comparison result, the second comparison result, the third comparison result, and the fourth comparison result. The fifth signal is a current signal used to control the turn-off of the field-effect transistor, so as to realize whether the AC-DC voltage conversion unit charges the device to be charged. The purpose of controlling whether the AC-DC voltage conversion unit charges the device to be charged is achieved by turning off the field-effect transistor.

[0035] Specifically, when the charging current is detected to be less than 200mA for 20 consecutive times, a timer is started and the output is turned off after 90 minutes. If the charging current is greater than 300mA for 63 consecutive seconds during this process, the controller will reset the timer. When the charging current is detected to be less than 40mA for 5 consecutive times, a 30-second countdown begins. When the charging current is detected to be greater than 300mA for 25 consecutive times within 30 seconds, the controller will reset the timer. When the charging current is detected to be less than 300mA for 5 consecutive times within 30 seconds, the controller will turn off the field transistor, thereby stopping the output of the overcharge protection intelligent switching circuit.

[0036] According to one embodiment of this application, such as Figure 1As shown, the circuit also includes a low-power detection unit 40, which is electrically connected to the tenth terminal of the second controller 32. When the first comparison result indicates that the real-time charging voltage is less than a preset voltage, the unit outputs a sixth signal at predetermined time intervals. This sixth signal causes the second controller 32 to control the AC / DC voltage conversion unit 10 to charge the device to be charged. For example, when a mobile phone is set to a healthy charging mode, it learns the user's sleep habits and automatically stops charging when the battery reaches 80% at night. This is to prevent the battery from continuously charging and reducing its lifespan. The charging process continues until the phone exits healthy mode some time before use, ensuring it is fully charged when in use. During this process, the phone's internal... When the device is in automatic non-charging mode, the charging system enters the overcharge protection disconnect mode. After the device is fully charged and enters the overcharge protection disconnect mode, the device's own power consumption will cause its battery level to drop, resulting in incomplete charging. Both of these situations prevent the device from fully charging. To address these issues, the low-power detection unit 40 sends a sixth signal every predetermined time interval, causing the second controller 32 to turn on the field-effect transistor 35, thus enabling the AC-DC voltage conversion unit 10 to charge the phone. Once the phone is fully charged, the second controller 32 disconnects the field-effect transistor, stopping the AC-DC voltage conversion unit 10 from charging the phone. This cycle repeats, ensuring the phone (i.e., the device to be charged) remains fully charged and preventing overcharging that could affect battery life. For example, if the predetermined time interval is set to 2t, the low-power detection unit 40 causes the second controller 32 to turn on the field-effect transistor 35 every 2t to enable the AC-DC voltage conversion unit 10 to charge the device.

[0037] According to an embodiment of this application, an overcharge protection intelligent switching device is also provided. This device includes the aforementioned overcharge protection intelligent switching circuit. The circuit includes an AC / DC voltage conversion unit, a normally-on identification unit, and an overcharge protection unit. The AC / DC voltage conversion unit is electrically connected to the device to be charged. The normally-on identification unit is electrically connected to the AC / DC voltage conversion unit and is used to obtain a real-time charging voltage from the AC / DC voltage conversion unit. Based on the real-time charging voltage, it determines whether the device to be charged is in a normally-on state or an overcharge protection state. When the device to be charged is in the normally-on state, the normally-on identification unit outputs a first signal. When in the overcharge protection state, the normally open identification unit outputs a second signal. The overcharge protection unit is electrically connected to the AC-DC voltage conversion unit and the normally open identification unit, respectively, and is used to obtain the real-time charging current of the AC-DC voltage conversion unit. In the normally open state, according to the first signal, the AC-DC voltage conversion unit is controlled to charge the device to be charged. In the overcharge protection state, according to the second signal and the real-time charging current, the AC-DC voltage conversion unit is controlled to charge the device to be charged, or the AC-DC voltage conversion unit is controlled to stop charging the device to be charged.

[0038] It should be noted that the above electrical connection can be a direct electrical connection or an indirect electrical connection. A direct electrical connection means that two devices are directly connected, while an indirect electrical connection means that there are other devices such as capacitors and resistors connected between the connected A and B.

[0039] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0040] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0041] The overcharge protection intelligent switching circuit of this application first identifies devices that need continuous charging (e.g., laptops) or devices that need overcharge protection (e.g., mobile phones) through a constant-current identification unit. When a device that needs continuous charging is identified, a first signal is generated and sent to the overcharge protection unit. The overcharge protection unit controls the AC-DC voltage conversion unit to charge the device based on the first signal, thus achieving the purpose of continuously charging the device that needs continuous charging. When a device that needs overcharge protection is identified, a second signal is generated and sent to the overcharge protection unit. The overcharge protection unit controls the AC-DC voltage conversion unit to charge the device based on the second signal and the real-time charging current obtained by the overcharge protection unit, or controls the AC-DC voltage conversion unit to stop charging the device, so as to ensure that the device that needs overcharge protection is fully charged. This achieves the purpose of identifying the device to be charged, thereby solving the problem that existing solutions cannot identify the device to be charged.

[0042] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A circuit for intelligent switching to prevent overcharge, characterized in that, include: An AC-DC voltage conversion unit is used for electrical connection to the device to be charged; A constant-on identification unit is electrically connected to the AC-DC voltage conversion unit. It is used to obtain the real-time charging voltage from the AC-DC voltage conversion unit and determine whether the device to be charged is in a constant-on state or an overcharge protection state based on the real-time charging voltage. When the device to be charged is in the constant-on state, the constant-on identification unit outputs a first signal. When the device to be charged is in the overcharge protection state, the constant-on identification unit outputs a second signal. An overcharge protection unit is electrically connected to the AC-DC voltage conversion unit and the normally-on identification unit, respectively. It is used to obtain the real-time charging current of the AC-DC voltage conversion unit from the AC-DC voltage conversion unit. In the normally-on state, it controls the AC-DC voltage conversion unit to charge the device to be charged according to the first signal. In the overcharge protection state, it controls the AC-DC voltage conversion unit to charge the device to be charged according to the second signal and the real-time charging current, or controls the AC-DC voltage conversion unit to stop charging the device to be charged.

2. The circuit according to claim 1, characterized in that, The constant-pass identification unit includes: The first comparator has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the first comparator is electrically connected to the AC-DC voltage conversion unit. The real-time charging voltage is input to the first input terminal of the first comparator. The second input terminal of the first comparator is used to input a preset voltage. The output terminal of the first comparator outputs a first comparison result. The first comparison result is used to characterize the magnitude relationship between the real-time charging voltage and the preset voltage.

3. The circuit according to claim 2, characterized in that, The constant-pass identification unit further includes: The first controller has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the first controller is electrically connected to the AC-DC voltage conversion unit. The real-time charging voltage is input to the first terminal of the first controller. The second terminal of the first controller is electrically connected to the first input terminal of the first comparator. The third terminal of the first controller is electrically connected to the output terminal of the first comparator. The fourth terminal of the first controller is electrically connected to the overcharge protection unit and is used to output the first signal or the second signal.

4. The circuit according to claim 2, characterized in that, The overcharge protection unit includes: The second comparator has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the second comparator is electrically connected to the AC-DC voltage conversion unit. The real-time charging current is input to the first input terminal of the second comparator. The second input terminal of the second comparator is used to input a first preset current. The output terminal of the second comparator outputs a second comparison result. The second comparison result is used to characterize the magnitude relationship between the real-time charging current and the first preset current.

5. The circuit according to claim 4, characterized in that, The overcharge protection unit also includes: The second controller has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the second controller is electrically connected to the normally connected identification unit and is used to receive the first signal or the second signal. The second terminal of the second controller is electrically connected to the AC-DC voltage conversion unit. The real-time charging current is input to the second terminal of the second controller. The third terminal of the second controller is electrically connected to the first input terminal of the second comparator. The fourth terminal of the second controller is electrically connected to the output terminal of the second comparator. The second controller is used to control the AC-DC voltage conversion unit to charge the device to be charged when receiving the first signal, and to transmit the real-time charging current to the second comparator when receiving the second signal, and to control the AC-DC voltage conversion unit to charge the device to be charged or to control the AC-DC voltage conversion unit to stop charging the device to be charged according to the second comparison result.

6. The circuit according to claim 5, characterized in that, The overcharge protection unit also includes: The third comparator has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the third comparator is electrically connected to the fifth terminal of the second controller. When the second comparison result indicates that the real-time charging current is less than the first preset current, the fifth terminal of the second controller outputs a third signal, which is the real-time charging current. The second input terminal of the third comparator is used to input the second preset current. The output terminal of the third comparator is electrically connected to the sixth terminal of the second controller. The output terminal of the third comparator outputs a third comparison result, which is used to characterize the relationship between the magnitude of the real-time charging current and the second preset current. The fourth comparator has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the fourth comparator is electrically connected to the seventh terminal of the second controller. When the second comparison result indicates that the real-time charging current is less than the first preset current, the seventh terminal of the second controller outputs a fourth signal, which is the real-time charging current. The second input terminal of the fourth comparator is used to input a third preset current, which is less than the second preset current. The output terminal of the fourth comparator is electrically connected to the eighth terminal of the second controller. The output terminal of the fourth comparator outputs a fourth comparison result, which is used to characterize the relationship between the magnitude of the real-time charging current and the third preset current.

7. The circuit according to claim 6, characterized in that, The second controller is also used to perform the following steps: If the first comparison result indicates that the real-time charging voltage is greater than or equal to the preset voltage, the AC-DC voltage conversion unit is controlled to charge the device to be charged. If the first comparison result indicates that the real-time charging voltage is less than the preset voltage, the real-time charging current is sent to the first input terminal of the second comparator. If the second comparison result indicates that the real-time charging current is greater than or equal to the first preset current, the AC-DC voltage conversion unit is controlled to charge the device to be charged. If the second comparison result indicates that the real-time charging current is less than the first preset current, the real-time charging current is sent to the first output terminal of the second comparator and the first input terminal of the third comparator, respectively. If the third comparison result indicates that the real-time charging current is less than the second preset current, the AC-DC voltage conversion unit is controlled to stop charging the device to be charged. If the third comparison result indicates that the real-time charging current is greater than or equal to the second preset current, the AC-DC voltage conversion unit is controlled to charge the device to be charged.

8. The circuit according to claim 6, characterized in that, The overcharge protection unit also includes: The field-effect transistor (FET) has its gate electrically connected to the first terminal of the second controller, the ninth terminal of the second controller, the AC / DC voltage conversion unit, and the normally-on identification unit. It has a first turn-off current and a second turn-off current, and the first turn-off current is greater than the second turn-off current. The second controller outputs a fifth signal at the ninth terminal of the second controller based on the first comparison result, the second comparison result, the third comparison result, and the fourth comparison result. The fifth signal is a current signal used to control the turn-off of the FET, so as to realize whether the AC / DC voltage conversion unit charges the device to be charged.

9. The circuit according to claim 5, characterized in that, The circuit also includes: The power depletion detection unit is electrically connected to the tenth terminal of the second controller. When the first comparison result indicates that the real-time charging voltage is less than the preset voltage, it outputs a sixth signal every predetermined time period. The sixth signal causes the second controller to control the AC-DC voltage conversion module to charge the device to be charged.

10. A device for intelligent switching to prevent overcharge, characterized in that, The circuit includes the overcharge protection intelligent switching circuit as described in any one of claims 1 to 9.

Images