Charging protection circuit and charging equipment
By designing an overcurrent protection module and a charging switch module in the charging protection circuit, and controlling the disconnection state of the charging circuit using the lock signal, the problem of low reliability of the overcurrent protection circuit in the prior art is solved, and higher circuit reliability and normal operation of the equipment are achieved.
Patent Information
- Application Number
- CN202420743650.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-10
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2034-04-10
AI Technical Summary
When an existing overcurrent protection circuit detects an overcurrent, it frequently closes and turns on the charging circuit, resulting in low circuit reliability and may overcurrent occur again, causing circuit damage and equipment not to work properly.
A charging protection circuit is designed, including an overcurrent protection module and a charging switch module. The overcurrent protection module detects current through sampling resistance. When the current is greater than the overcurrent protection value, it outputs a lock signal, and controls the charging switch module to be continuously disconnected to avoid repeated closing and opening of the charging circuit.
It effectively avoids frequent switching of the charging circuit part repeatedly closing and opening, improves the reliability of the circuit, prevents circuit damage and equipment from not working properly.
Smart Images
Figure CN222620704U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of power electronics technology, and in particular to a charging protection circuit and a charging device. Background Art
[0002] As an energy supply device, chargers have been widely used to charge various electronic products with batteries. When charging electronic products, if the output circuit of the charger is short-circuited due to some accidental short circuit, the charger will damage the internal circuit due to excessive loop current. Therefore, it is necessary to design overcurrent protection or similar methods to deal with this situation. Overcurrent protection is mainly to prevent short circuit of the main circuit. In the design of existing overcurrent protection circuits, when overcurrent is detected, the charging output is usually controlled to be turned off. After the charging output is turned off, the circuit is in an overcurrent state. In this way, the charging circuit will automatically open again, which will cause the charging circuit to be in a frequent switching state of repeated closing and opening, and the circuit reliability is low. Moreover, after the charging circuit is automatically opened again, if the overcurrent problem of the circuit is not effectively solved at this time, overcurrent may still occur again when the circuit is automatically opened, which may easily cause damage to the circuit and cause the equipment to fail to work properly. Utility Model Content
[0003] The implementation method of the present application mainly solves the technical problem of low reliability of the existing overcurrent protection method.
[0004] In order to solve the above technical problems, a technical solution adopted in the embodiment of the present application is: providing a charging protection circuit, including an overcurrent protection module and a charging switch module, the overcurrent protection module is connected to a charging power supply, the overcurrent protection module is connected to the control end of the charging switch module, and the charging switch module is respectively connected to the charging power supply and the load to be charged, so as to charge the load to be charged in combination with the charging power supply; wherein, the overcurrent protection module includes a sampling resistor, a first end of the sampling resistor is connected to the negative electrode of the charging power supply, and a second end of the sampling resistor is connected to the negative electrode of the load to be charged, and the overcurrent protection module is used to output a locking signal when it is detected that the current of the sampling resistor is greater than the overcurrent protection value, so as to control the charging switch module to be continuously disconnected, thereby controlling the charging power supply to stop charging the load to be charged.
[0005] In some embodiments, the overcurrent protection module includes an overcurrent self-locking unit, which includes a resistor R1, a resistor R2, a resistor R3, a switch tube Q2 and a switch tube Q3, the first end of the switch tube Q3 is connected to the positive electrode of the charging power supply through the resistor R1, the second end of the switch tube Q3 is connected to the negative electrode of the charging power supply, the control end of the switch tube Q3 is connected to the second end of the switch tube Q2 through the resistor R3, the first end of the switch tube Q2 is connected to the positive electrode of the charging power supply, the control end of the switch tube Q2 is connected to the first end of the switch tube Q3 through the resistor R2, and the second end of the switch tube Q2 is connected to the control end of the charging switch module.
[0006] In some embodiments, the overcurrent protection module further includes an anti-backflow unit, which includes a diode D1, an anode of the diode D1 connected to the second end of the switch tube Q2, and a cathode of the diode D1 connected to the control end of the charging switch module.
[0007] In some embodiments, the backflow prevention unit further includes a current limiting resistor R5 , and the anode of the diode D1 is connected to the second end of the switch tube Q2 through the current limiting resistor R5 .
[0008] In some embodiments, the overcurrent protection module also includes a filtering unit, which includes a capacitor C2 and a resistor R4, wherein a first end of the capacitor C2 is connected to a control end of the switch tube Q3, a second end of the capacitor C2 is connected to a negative electrode of the charging power supply, a first end of the resistor R4 is connected to a control end of the switch tube Q3, and a second end of the resistor R4 is connected to a negative electrode of the charging power supply through the sampling resistor.
[0009] In some embodiments, the switch tube Q2 is a PNP transistor, and the switch tube Q3 is an NPN transistor.
[0010] In some embodiments, the charging switch module includes a voltage dividing unit and a switch tube Q1, the first end of the voltage dividing unit is connected to the positive electrode of the charging power supply, the second end of the voltage dividing unit is connected to the negative electrode of the charging power supply through the sampling resistor, the third end of the voltage dividing unit is connected to the control end of the switch tube Q1, the first end of the switch tube Q1 is connected to the positive electrode of the charging power supply, and the second end of the switch tube Q1 is connected to the positive electrode of the load to be charged.
[0011] In some embodiments, the voltage dividing unit includes a resistor R6 and a resistor R7, the first end of the resistor R6 is connected to the positive electrode of the charging power supply, the second end of the resistor R6 is connected to the control end of the switch tube Q1, the first end of the resistor R7 is connected to the second end of the resistor R6, and the second end of the resistor R7 is connected to the negative electrode of the charging power supply through the sampling resistor.
[0012] In some embodiments, the charging protection circuit is further provided with an unlocking switch, and the overcurrent protection module and the charging switch module are both connected to the positive electrode of the charging power source through the unlocking switch.
[0013] In order to solve the above technical problems, another technical solution adopted in the embodiment of the present application is: providing a charging device, including the charging protection circuit as described above.
[0014] Different from the related art, the present application provides a charging protection circuit and a charging device. The charging protection circuit includes an overcurrent protection module and a charging switch module, the overcurrent protection module is connected to a charging power supply, the overcurrent protection module is connected to the control end of the charging switch module, and the charging switch module is respectively connected to the charging power supply and the load to be charged, so as to charge the load to be charged in combination with the charging power supply; wherein, the overcurrent protection module includes a sampling resistor, the first end of the sampling resistor is connected to the negative electrode of the charging power supply, and the second end of the sampling resistor is connected to the negative electrode of the load to be charged, and the overcurrent protection module is used to output a locking signal when it is detected that the current of the sampling resistor is greater than the overcurrent protection value, so as to control the charging switch module to be continuously disconnected, so that the charging power supply stops charging the load to be charged, and the overcurrent protection function is realized. Even if the current of the sampling resistor is lower than the overcurrent protection value after charging stops, the overcurrent protection module can still control the charging switch module to be disconnected, so as to avoid the frequent switching of the charging circuit part repeatedly closing and opening, and improve the reliability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 is a structural block diagram of a charging protection circuit provided in an embodiment of the present application;
[0016] Figure 2 It is a structural schematic diagram of a charging protection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION
[0017] For ease of understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "connected" to another element, it can be directly connected to another element, or there can be one or more centered elements therebetween. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by technicians in the technical field of the present application. The terms used in this specification in the specification of the present application are only for the purpose of describing specific embodiments and are not used to limit the present application. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.
[0018] When an overcurrent is detected, the existing overcurrent protection circuit usually controls to shut down the charging output. After the charging output is shut down, the charging circuit is partially disconnected and is in a non-current state. In this way, the charging circuit will automatically open again. After the charging circuit is automatically opened again, if the overcurrent problem of the circuit is not effectively solved at this time, overcurrent may still occur again when the charging circuit is automatically opened, which will cause the charging circuit to be in a frequent switching state of repeated closing and opening, which is easy to cause damage to the circuit and also easy to cause the equipment to fail to work normally, and the circuit reliability is low.
[0019] In response to the above technical problems, an embodiment of the present application provides a charging device, which includes a charging power supply and a charging protection circuit. The charging power supply charges the load to be charged through the charging protection circuit, and implements an overcurrent protection function through the charging protection circuit. When the charging current is too large, the charging protection circuit controls the charging circuit part between the charging power supply and the load to be charged to be disconnected, and maintains the disconnected state of the charging circuit part, so as to avoid frequent switching of the charging circuit part between being repeatedly closed and opened.
[0020] For details, please refer to Figure 1 The charging protection circuit 100 includes an overcurrent protection module 11 and a charging switch module 12. The overcurrent protection module 11 is connected to a charging power source 20. The overcurrent protection module 11 is connected to the control end of the charging switch module 12. The charging switch module 12 is respectively connected to the charging power source 20 and the load to be charged 30, so as to charge the load to be charged 30 in combination with the charging power source 20. The overcurrent protection module 11 includes a sampling resistor Rs, a first end of the sampling resistor Rs is connected to the negative electrode of the charging power source 20, and a second end of the sampling resistor Rs is connected to the negative electrode of the load to be charged 30. The current of the sampling resistor Rs is the load current. When the overcurrent protection module 11 detects that the current of the sampling resistor Rs is greater than the overcurrent protection value, it outputs a locking signal to control the charging switch module 12 to be continuously disconnected, so that the charging power source 20 stops charging the load to be charged. It can be understood that the locking signal means that when the current of the sampling resistor Rs is greater than the overcurrent protection value and the locking signal is triggered, the locking signal will continue to exist, even if the charging switch module is disconnected and stops charging the load to be charged, the current of the sampling resistor Rs drops to less than the overcurrent protection value, and the locking signal remains unchanged, so the charging switch module 12 can be controlled to remain disconnected until the charging power supply 20 stops supplying power to the charging protection circuit 100 and the overcurrent protection module 11 stops outputting the locking signal. Based on the above circuit structure, the charging protection circuit can avoid the frequent switching of the charging circuit part repeatedly closing and opening, thereby improving the reliability of the charging circuit.
[0021] Please combine Figure 2 , Figure 2 V1 is used to represent Figure 1The charging power source 20 in the circuit is represented by resistor R9. Figure 1 The load to be charged 30 in the figure, switch S2 represents the load switch on the load side. Figure 2 As shown, the overcurrent protection module 11 includes an overcurrent self-locking unit 111, wherein the overcurrent self-locking unit 111 includes a resistor R1, a resistor R2, a resistor R3, a switch tube Q2 and a switch tube Q3, the first end of the switch tube Q3 is connected to the positive electrode of the charging power source V1 through the resistor R1, the second end of the switch tube Q3 is connected to the negative electrode of the charging power source V1, the control end of the switch tube Q3 is connected to the second end of the switch tube Q2 through the resistor R3, the first end of the switch tube Q2 is connected to the positive electrode of the charging power source V1, the control end of the switch tube Q2 is connected to the first end of the switch tube Q3 through the resistor R2, and the second end of the switch tube Q2 is connected to the control end of the charging switch module 12. The overcurrent self-locking unit 111 can be combined with the current of the sampling resistor Rs, and when the current is greater than the overcurrent protection value, a locking signal is output through the second end of the switch tube Q2 to control the charging switch module 12 to disconnect, thereby controlling the charging power source V1 to stop charging the load R9 to be charged, so as to achieve the function of overcurrent protection. Among them, the switch tube Q2 in the embodiment of the present application is a PNP type transistor, and the switch tube Q3 is an NPN type transistor.
[0022] like Figure 2 As shown, the overcurrent protection module 11 also includes a filtering unit 113, which can filter and remove unnecessary signal frequencies. The filtering unit includes a capacitor C2 and a resistor R4, a first end of the capacitor C2 is connected to the control end of the switch tube Q3, a second end of the capacitor C2 is connected to the negative electrode of the charging power source V1, a first end of the resistor R4 is connected to the control end of the switch tube Q3, and a second end of the resistor R4 is connected to the negative electrode of the charging power source V1 through a sampling resistor Rs.
[0023] In some embodiments, Figure 2 As shown, the overcurrent protection module 11 also includes an anti-backflow unit 112, which includes a diode D1, the anode of the diode D1 is connected to the second end of the switch tube Q2, and the cathode of the diode D1 is connected to the control end of the charging switch module. The diode D1 can prevent the current from flowing backward. In some embodiments, the anti-backflow unit 112 also includes a current limiting resistor R5, which is connected in series on the branch where the diode D1 is located, for example Figure 2 The anode of the diode D1 shown is connected to the second end of the switch tube Q2 through the current limiting resistor R5. The current limiting resistor R5 is used to achieve current limiting to prevent excessive current from burning out components.
[0024] like Figure 2As shown, the charging switch module 12 includes a voltage dividing unit 121 and a switch tube Q1, wherein the voltage dividing unit 121 includes a resistor R6 and a resistor R7, the first end of the resistor R6 is connected to the positive electrode of the charging power source V1, the second end of the resistor R6 is connected to the control end of the switch tube Q1, the first end of the resistor R7 is connected to the second end of the resistor R6, the second end of the resistor R7 is connected to the negative electrode of the charging power source V1 through the sampling resistor Rs, the first end of the switch tube Q1 is connected to the positive electrode of the charging power source V1, and the second end of the switch tube Q1 is connected to the positive electrode of the load to be charged R9. When the switch tube Q1 is turned on, the charging protection circuit charges normally. If the current of the sampling resistor Rs is greater than the overcurrent protection value, the overcurrent protection module outputs a locking signal, pulls up the control end voltage of the switch tube Q1, so that the Vgs of the switch tube Q1 cannot reach the start voltage, and the switch tube Q1 is disconnected, thereby controlling the charging power source V1 to stop charging the load to be charged R9.
[0025] Specifically, when the charging protection circuit is charging normally, the charging switch module 12 is in the on state, and the charging power source V1 charges the load R9 to be charged through the charging switch module 12. In this process, the current of the sampling resistor Rs, that is, the load current Iout, is lower than the overcurrent protection value, and the voltage of the sampling resistor Rs is Iout*Rs. Even in combination with the resistor R4, the Vbe of the switch tube Q3 cannot reach the turn-on voltage, so the switch tube Q3 is in the off state. When the switch tube Q3 is in the off state, the control end of the switch tube Q2 is pulled up to approximately equal to the first end of the switch tube Q2 through the resistors R1 and R2, which cannot meet the turn-on voltage of the switch tube Q2. The switch tube Q2 is in the off state, and the control end of the switch tube Q1 is provided with a turn-on voltage by the charging power supply V1 through the resistor R6. At this time, the Vgs of the switch tube Q1 is V1*R6 / (R6+R7). For example, assuming that V1 is 30V and R6=2R7, the Vgs of the switch tube Q1 is 20V, which is greater than its turn-on voltage. The switch tube Q1 is normally turned on, and the charging power supply V1 normally charges the load R9 to be charged. It can be understood that in different application environments, the overcurrent protection value can be set according to the resistance value of the sampling resistor Rs in combination with the use scenario, and the sampling resistor Rs with a suitable resistance value can also be set according to the requirements of the overcurrent protection value in the actual use scenario.
[0026] When an overcurrent condition occurs during the charging process of the charging protection circuit, the current of the sampling resistor Rs is greater than the overcurrent protection value. At this time, the voltage I out*Rs of the sampling resistor is sufficient to drive the control end of the switch tube Q3 through the resistor R4, so that the switch tube Q3 is turned on. When the switch tube Q3 is in the on state, the control end of the switch tube Q2 is pulled down to GND by the resistor R2 and the switch tube Q3, and the Vbe of the switch tube Q2 reaches the turn-on voltage, the switch tube Q2 is turned on, and the output voltage of the switch tube Q2 is approximately the voltage of the charging power supply V1. For example, assuming that V1 is 30V and the voltage drop of the diode D1 is 0.7V, the voltage of the control end of the switch tube Q1 is pulled up by the resistor R5 and the diode D1, which is approximately 30V-0.7V=29.3V, and the voltage of the first end of the switch tube Q1 is equal to V1=30V. At this time, the Vgs of the switch tube Q1 is approximately 30V-29.3V=0.7V, which does not reach its turn-on voltage, so the switch tube Q1 is disconnected, and the charging power supply V1 stops charging the load R9 to be charged. At the same time, when the switch tube Q2 is turned on, the output voltage of the switch tube Q2 drives the control end of the switch tube Q3 through the resistor R3, so that the switch tube Q3 is turned on. Even if the switch tube Q1 is turned off and the load current disappears, the switch tube Q3 can still maintain the on state, so that the switch tube Q1 is continuously turned off. Therefore, the frequent switching of the charging circuit part repeatedly turning on and off in the existing solution can be avoided, and the reliability of the circuit is improved.
[0027] In some embodiments, the charging protection circuit 100 is further provided with an unlocking switch, such as Figure 2 As shown in the figure, the unlocking switch is represented by switch S1, and the overcurrent protection module 11 and the charging switch module 12 are both connected to the positive pole of the charging power source V1 through the unlocking switch S1. When the overcurrent condition causes the switch tube Q1 to be disconnected, if it is necessary to restore to the state of continuing to charge the load to be charged, the unlocking switch S1 can be disconnected, and the power supply to the switch tubes Q2 and Q3 can be stopped, so that the switch tubes Q2 and Q3 are disconnected due to the loss of power supply, and then the unlocking switch S1 is closed to restore to the normal charging state. The setting of the unlocking switch can facilitate the staff to restore the charging state of the charging protection circuit at an appropriate time. For example, after solving the fault that causes the overcurrent condition, the normal charging state can be restored through the unlocking switch. It is not only easy to operate and low in cost, but also ensures the safety of the circuit.
[0028] The charging protection circuit provided in the embodiment of the present application includes an overcurrent protection module and a charging switch module. The overcurrent protection module includes a sampling resistor, through which the load current can be detected. When the load current is overcurrent, the circuit can control the charging circuit part between the charging power supply and the load to be charged to be disconnected, and maintain the disconnected state of the charging circuit part. While realizing the overcurrent protection function, it can also avoid the frequent switching of the charging circuit part repeatedly closing and opening, thereby improving the reliability of the circuit.
[0029] It should be noted that the preferred embodiments of the present application are given in the specification and drawings of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described in the specification. These embodiments are not used as additional limitations on the content of the present application. The purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all regarded as the scope of the description of the present application; further, for ordinary technicians in this field, they can be improved or transformed according to the above description, and all these improvements and transformations should belong to the scope of protection of the claims attached to the present application.
Claims
1. A charging protection circuit, characterized in that: The device comprises an overcurrent protection module and a charging switch module, wherein the overcurrent protection module is connected to a charging power source, the overcurrent protection module is connected to a control end of the charging switch module, and the charging switch module is respectively connected to the charging power source and a load to be charged, so as to charge the load to be charged in combination with the charging power source; Wherein, the overcurrent protection module includes a sampling resistor, a first end of the sampling resistor is connected to the negative electrode of the charging power supply, and a second end of the sampling resistor is connected to the negative electrode of the load to be charged. The overcurrent protection module is used to output a locking signal when it is detected that the current of the sampling resistor is greater than the overcurrent protection value, so as to control the charging switch module to be continuously disconnected, thereby controlling the charging power supply to stop charging the load to be charged; The overcurrent protection module includes an overcurrent self-locking unit, which includes a resistor R1, a resistor R2, a resistor R3, a switch tube Q2 and a switch tube Q3. The first end of the switch tube Q3 is connected to the positive electrode of the charging power supply through the resistor R1, the second end of the switch tube Q3 is connected to the negative electrode of the charging power supply, the control end of the switch tube Q3 is connected to the second end of the switch tube Q2 through the resistor R3, the first end of the switch tube Q2 is connected to the positive electrode of the charging power supply, the control end of the switch tube Q2 is connected to the first end of the switch tube Q3 through the resistor R2, and the second end of the switch tube Q2 is connected to the control end of the charging switch module.
2. The charging protection circuit according to claim 1, characterized in that: The overcurrent protection module further includes an anti-backflow unit, which includes a diode D1, an anode of the diode D1 is connected to the second end of the switch tube Q2, and a cathode of the diode D1 is connected to the control end of the charging switch module.
3. The charging protection circuit according to claim 2, characterized in that: The backflow prevention unit further includes a current limiting resistor R5 , and the anode of the diode D1 is connected to the second end of the switch tube Q2 through the current limiting resistor R5 .
4. The charging protection circuit according to claim 2, characterized in that: The overcurrent protection module also includes a filtering unit, which includes a capacitor C2 and a resistor R4, a first end of the capacitor C2 is connected to the control end of the switch tube Q3, a second end of the capacitor C2 is connected to the negative electrode of the charging power supply, a first end of the resistor R4 is connected to the control end of the switch tube Q3, and a second end of the resistor R4 is connected to the negative electrode of the charging power supply through the sampling resistor.
5. The charging protection circuit according to claim 1, characterized in that: The switch tube Q2 is a PNP transistor, and the switch tube Q3 is an NPN transistor.
6. The charging protection circuit according to claim 1, characterized in that: The charging switch module includes a voltage dividing unit and a switch tube Q1, the first end of the voltage dividing unit is connected to the positive electrode of the charging power supply, the second end of the voltage dividing unit is connected to the negative electrode of the charging power supply through the sampling resistor, the third end of the voltage dividing unit is connected to the control end of the switch tube Q1, the first end of the switch tube Q1 is connected to the positive electrode of the charging power supply, and the second end of the switch tube Q1 is connected to the positive electrode of the load to be charged.
7. The charging protection circuit according to claim 6, characterized in that: The voltage dividing unit includes a resistor R6 and a resistor R7, wherein a first end of the resistor R6 is connected to the positive electrode of the charging power source, a second end of the resistor R6 is connected to the control end of the switch tube Q1, a first end of the resistor R7 is connected to the second end of the resistor R6, and a second end of the resistor R7 is connected to the negative electrode of the charging power source through the sampling resistor.
8. The charging protection circuit according to claim 1, characterized in that: The charging protection circuit is also provided with an unlocking switch, and the overcurrent protection module and the charging switch module are both connected to the positive electrode of the charging power supply through the unlocking switch.
9. A charging device, characterized in that: Comprising a charging protection circuit as described in any one of claims 1-8.