Charging protection circuit and charger
By designing a charging protection circuit in the charger, the switch tube and switch are controlled to be in a conducting state, the energy discharge of the first capacitor is achieved, which solves the problem of the switch tube in the charger withstand high voltage stress and improves the reliability of the charger and charging efficiency.
Patent Information
- Application Number
- CN202411605028.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-02-14
AI Technical Summary
In existing chargers, when the AC voltage returns to normal but the primary capacitor voltage has not dropped to a safe level, the switch tube will bear high voltage stress, which can easily lead to failure of the switch tube and affect the reliability of the charger.
Design a charging protection circuit, by controlling both the first switch tube and the first switch to be in a conducting state, the energy of the first capacitor is discharged through the formed path, and the energy pressure relief processing is realized, thereby quickly restoring the voltage and charging process. .
Through energy pressure relief processing, the charger's voltage and charging process can be quickly restored, avoiding user waiting time and improving the reliability of the charger.
Smart Images
Figure CN119448748A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of charging technology, and specifically relates to a charging protection circuit and a charger. Background Art
[0002] At present, in order to protect the charger from being damaged, a voltage acquisition module is usually set in the charger to sample the AC voltage connected to the charger, and when the collected AC voltage reaches the preset protection value, the pulse width modulation (PWM) module of the charger will be controlled to stop sending the pulse width signal, so that the energy of the primary side of the charger cannot be transferred to the secondary side, so as to achieve the purpose of protecting the charger. However, when the AC voltage collected by the voltage acquisition module returns to a normal level, and the voltage across the capacitor of the primary side does not drop to a safe voltage level, the switch tube of the primary side will be subjected to a higher voltage stress, which may easily lead to failure of the switch tube, thereby affecting the reliability of the charger.
[0003] It can be seen that the charger in the related art has the problem of poor reliability. Summary of the invention
[0004] The purpose of the embodiments of the present application is to provide a charging protection circuit and a charger, which can solve the problem of poor reliability of chargers in related technologies.
[0005] In order to solve the above technical problems, this application is implemented as follows:
[0006] In a first aspect, an embodiment of the present application provides a charging protection circuit, including: a power supply, a rectifier module, a first capacitor, a first switch tube, a current detection resistor and a pressure relief module, wherein the rectifier module is used to convert the alternating current output by the power supply into direct current, the first end of the first capacitor is electrically connected to the output end of the rectifier module, the second end of the first capacitor is grounded, the output end of the rectifier module is also electrically connected to the first end of the current detection resistor through the first switch tube, the second end of the current detection resistor is grounded, the pressure relief module includes a first switch, the input end of the first switch is electrically connected to the first end of the current detection resistor, and the output end of the first switch is grounded;
[0007] Wherein, when the voltage of the power supply drops from the first voltage to the first preset voltage, the first switch tube and the first switch are both in the on state.
[0008] In a second aspect, an embodiment of the present application provides a charger, comprising the charging protection circuit described in the first aspect above.
[0009] In the embodiment of the present application, by controlling the first switching tube and the first switch to be in the on state, the energy of the first capacitor can be discharged through the path formed by the first switching tube and the first switch, so as to realize the energy pressure relief processing of the first capacitor, so that the voltage of the first capacitor can be quickly restored to a normal level, and then the charger can quickly resume the charging process, thereby avoiding long waiting times for users and improving the reliability of the charger. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 is a circuit diagram of a charging protection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION
[0011] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0012] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.
[0013] like Figure 1 As shown, an embodiment of the present application provides a charging protection circuit, which can be applied to a charger, and the charging protection circuit includes: a power supply 101, a rectifier module 102, a first capacitor 103, a first switch tube 104, a current detection resistor 105 and a pressure relief module 106, the rectifier module 102 is used to convert the alternating current output by the power supply 101 into direct current, the first end of the first capacitor 103 is electrically connected to the output end of the rectifier module 102, the second end of the first capacitor 103 is grounded, the output end of the rectifier module 102 is also electrically connected to the first end of the current detection resistor 105 through the first switch tube 104, the second end of the current detection resistor 105 is grounded, the pressure relief module 106 includes a first switch 1061, the input end of the first switch 1061 is electrically connected to the first end of the current detection resistor 105, and the output end of the first switch 1061 is grounded;
[0014] When the voltage of the power source 101 drops from the first voltage to the first preset voltage, the first switch tube 104 and the first switch 1061 are both in the on state.
[0015] The voltage of the power supply 101 drops from the first voltage to the first preset voltage, which can be understood as the voltage of the AC power supply connected to the power supply 101 dropping from a higher value to a normal value, that is, the first preset voltage can be understood as the normal voltage value of the AC power supply connected to the power supply 101, such as the first voltage can be set to 380V, and the first preset voltage can be set to 220V.
[0016] The above-mentioned first switch 1061 being in the on state can be understood as the first switch tube 104 can be grounded not only through the path where the current detection resistor 105 is located, but also through the path where the first switch 1061 is located.
[0017] In this embodiment, by controlling the first switch tube 104 and the first switch 1061 to be in the on state, the energy of the first capacitor 103 can be discharged through the path formed by the first switch tube 104 and the first switch 1061, so as to realize the energy pressure relief processing of the first capacitor 103, so that the voltage of the first capacitor 103 can be quickly restored to a normal level, and then the charger can quickly resume the charging process, thereby avoiding long waiting times for users and improving the reliability of the charger.
[0018] In some embodiments, the charging protection circuit further includes a first voltage detection module 107 , and the first voltage detection module 107 is used to detect the voltage of the power source 101 .
[0019] In this embodiment, the voltage of the power supply 101 can be detected by the first voltage detection module 107, and when the first voltage detection module 107 detects that the voltage of the power supply 101 drops from the first voltage to the first preset voltage, the first switch tube 104 and the first switch 1061 can be controlled to be in the on state to achieve energy pressure relief processing of the first capacitor 103, so that the voltage of the first capacitor 103 can be quickly restored to a normal level.
[0020] In some embodiments, the charging protection circuit further includes a second voltage acquisition module 108, and the second voltage acquisition module 108 is used to collect the voltage across the first capacitor 103;
[0021] When the difference between the voltage across the first capacitor 103 and the second preset voltage collected by the second voltage collection module 108 is smaller than the preset value, the conduction degree of the first switch tube 104 is adjusted to increase the impedance of the first switch tube 104 .
[0022] In the process of pressure relief processing of the energy of the first capacitor 103 through the path formed by the first switch tube 104 and the first switch 1061, the voltage across the first capacitor 103 can be continuously collected through the second voltage collection module 108, so that when the difference between the voltage across the first capacitor 103 and the second preset voltage is less than the preset value, the conduction degree of the first switch tube 104 is adjusted to increase the impedance of the first switch tube 104, thereby avoiding the peak voltage caused when the first switch tube 104 is completely in the cut-off state, thereby improving the stability of the pressure relief process of the first capacitor 103.
[0023] The above adjustment of the conduction degree of the first switch tube 104 can be understood as adjusting the duty cycle of the first switch tube 104, that is, adjusting the ratio of the power-on time of the first switch tube 104 in the pulse width modulation signal to the total cycle time. For example, if the duty cycle of the first switch tube 104 is 50%, the first switch tube 104 is turned on for half of each pulse cycle and turned off for half of each pulse cycle.
[0024] In some embodiments, the charging protection circuit further includes a chip module 109 , and the second voltage acquisition module 108 and the chip module 109 can be integrated.
[0025] In some embodiments, the charging protection circuit also includes a third voltage acquisition module 1010, a first coil winding 1011 and a second coil winding 1012, the input end of the first coil winding 1011 is electrically connected to the output end of the rectifier module 102, the output end of the first coil winding 1011 is electrically connected to the first end of the current detection resistor 105 through the first switch tube 104, the first coil winding 1011 is coupled to the second coil winding 1012, and the third voltage acquisition module 1010 is used to collect the voltage of the second coil winding 1012.
[0026] Since the second coil winding 1012 is coupled to the first coil winding 1011, after the voltage of the second coil winding 1012 is acquired by the third voltage acquisition module 1010, the voltage of the first coil winding 1011 can be calculated based on the voltage ratio between the first coil winding 1011 and the second coil winding 1012, thereby acquiring the voltage across the first capacitor 103.
[0027] In some embodiments, the charging protection circuit further includes an overvoltage protection module 1013 and a pulse width modulation module 1014, the overvoltage protection module 1013 is electrically connected to the third voltage acquisition module 1010 and the pulse width modulation module 1014 respectively, and the pulse width modulation module 1014 is also electrically connected to the gate of the first switch tube 104;
[0028] Among them, when the voltage of the second coil winding 1012 collected by the third voltage collection module 1010 is higher than the third preset voltage, the overvoltage protection module 1013 sends a control signal to the pulse width modulation module 1014 to make the pulse width modulation module 1014 turn off the first switch tube 104, thereby protecting the internal circuit of the charger.
[0029] In some embodiments, the overvoltage protection module 1013 and the pulse width modulation module 1014 are also electrically connected to the chip module 109 .
[0030] In some embodiments, the pressure relief module 106 also includes a driving module 1062, which is electrically connected to the overvoltage protection module 1013 and the first switch 1061, respectively. After the overvoltage protection module 1013 receives a message that the voltage of the power supply 101 drops from the first voltage to the first preset voltage, the overvoltage protection module 1013 can output control information to the driving module 1062 to control the first switch 1061 to be in an on state through the driving module 1062.
[0031] In some embodiments, the charging protection circuit also includes an upper bias resistor 1015 and a lower bias resistor 1016, one end of the second coil winding 1012 is grounded, and the other end is electrically connected to the first end of the upper bias resistor 1015, the second end of the upper bias resistor 1015 is electrically connected to the first end of the lower bias resistor 1016, the second end of the lower bias resistor 1016 is grounded, and the third voltage acquisition module 1010 is electrically connected to the second end of the upper bias resistor 1015.
[0032] In some embodiments, the charging protection circuit also includes a first diode 1017 and a second capacitor 1018, the positive electrode of the first diode 1017 is electrically connected to the first end of the bias resistor 1015, the negative electrode of the first diode 1017 is electrically connected to the first end of the second capacitor 1018, and the second end of the second capacitor 1018 is grounded.
[0033] In some embodiments, the charging protection circuit includes a power supply 101, a rectifier module 102, a first capacitor 103, a first switch tube 104, a current detection resistor 105, and a pressure relief module 106, which can be used to form a front-end circuit of a charger, and the front-end circuit of the charger also includes a current detection module 1019, a fuse 1020, and other devices. The current detection module 1019 is used to detect the voltage across the current detection resistor 105;
[0034] The charger also includes a back-end circuit, which includes a power output terminal 201, a third coil winding 202, a second capacitor 203 and a second switch tube 204, a protocol control module 205 and a synchronous rectification drive module 206 and other components;
[0035] The third coil winding 202 is coupled to the first coil winding 1011 , and the power output terminal 201 is used to be electrically connected to an external device to be charged.
[0036] In some embodiments, Figure 1 As shown, the potential direction of the end of the first coil winding 1011 marked with the first black circle 10111, the potential direction of the end of the second coil winding 1012 marked with the second black circle 10121, and the potential direction of the end of the third coil winding 202 marked with the third black circle 2021 can be the same end, that is, the potential direction of the end of the first coil winding 1011 marked with the first black circle 10111, the potential direction of the end of the second coil winding 1012 marked with the second black circle 10121, and the potential direction of the end of the third coil winding 202 marked with the third black circle 2021 are the same.
[0037] Correspondingly, the potential direction of the grounding end of the second coil winding 1012, the potential direction of the input end of the first coil winding 1011, and the potential direction of the first end of the third coil winding 202 can be the same end, that is, the potential direction of the grounding end of the second coil winding 1012, the potential direction of the input end of the first coil winding 1011, and the potential direction of the first end of the third coil winding 202 are the same.
[0038] The first end of the third coil winding 202 is an end of the third coil winding 202 electrically connected to the second switch tube 204 .
[0039] In some embodiments, the working principle of the third voltage acquisition module 1010 sampling the voltage of the second coil winding 1012 is as follows:
[0040] During normal operation of the charging protection circuit, the potential direction of the ground terminal of the second coil winding 1012 and the potential direction of the input terminal of the first coil winding 1011 are the same as each other, that is, the potential direction of the ground terminal of the second coil winding 1012 is the same as the potential direction of the input terminal of the first coil winding 1011; and when the second coil winding 1012 is turned on, the ground terminal of the second coil winding 1012 is a high potential, and the non-ground terminal of the second coil winding 1012 is a negative voltage; at this time, the current output by the built-in current source of the pulse width modulation module 1014 will flow out in two ways through the external pins of the third voltage acquisition module 1010, so that the voltage on the second coil winding 1012 will form a conversion relationship with the current output by the pulse width modulation module 1014, that is, the voltage value of the second coil winding 1012 can be calculated by the current output by the pulse width modulation module 1014, thereby realizing the voltage detection of the first coil winding 1011.
[0041] The front-end circuit can be understood as the primary circuit of the charger for accessing the AC power supply, and the back-end circuit can be understood as the secondary circuit of the charger for accessing the charging interface of mobile phones, tablet computers and other devices waiting to be charged.
[0042] In some embodiments, if the voltage of the power supply 101 collected by the first voltage detection module 107 is V1, and the voltage across the first capacitor 103 collected by the second voltage collection module 108 is V2, during normal operation of the charger, that is, when the charger charges the device to be charged at a stable conventional voltage, V2 is generally equal to 1.414*V1.
[0043] During the normal operation of the charger, the second voltage acquisition module 108 is usually in a closed state. At this time, the voltage across the first capacitor 103 can be acquired through the third voltage acquisition module 1010, and the second coil winding 1012 can be used to provide a power source for the chip module 109 to support the operation of the chip module 109 and reduce the power consumption of the charger. If the charger is in the overvoltage protection period, the second voltage acquisition module 108 can be started, and the voltage across the first capacitor 103 can be acquired through the second voltage acquisition module 108.
[0044] For example, when the AC power supply connected to the power supply 101 is in an abnormally high voltage state, the voltage across the first capacitor 103 will also be quickly pulled to a higher level; at this time, if the voltage across the first capacitor 103 acquired by the third voltage acquisition module 1010 is higher than the voltage protection threshold V3, the third voltage acquisition module 1010 can pass the acquired voltage signal to the overvoltage protection module 1013, so that the overvoltage protection module 1013 sends a control signal to the pulse width modulation module 1014 based on the received voltage signal, so that the pulse width modulation module 1014 turns off the first switch tube 104, thereby protecting the internal circuit of the charger.
[0045] When the charger is in overvoltage protection, that is, when the overvoltage protection module 1013 sends a control signal to the pulse width modulation module 1014 to make the pulse width modulation module 1014 turn off the first switch tube 104, the path where the second voltage acquisition module 108 is located can be controlled to be opened, so that the chip module 109 can simultaneously collect the voltage across the first capacitor 103 and the voltage of the power supply 101.
[0046] For example, the voltage across the first capacitor 103 may be collected through the second voltage collection module 108 , and the voltage of the power supply 101 may be collected through the first voltage detection module 107 .
[0047] When the voltage of the power supply 101 detected by the first voltage detection module 107 falls back to a safe voltage range, such as from the first voltage to the first preset voltage; at this time, the voltage protection threshold V3 will be greater than 1.414 times the safe voltage, that is, the voltage protection threshold V3 will be greater than 1.414 times the first preset voltage; and, since the first capacitor 103 cannot discharge energy at this time, the voltage across the first capacitor 103 will still be greater than the voltage protection threshold V3; therefore, the chip module 109 can control the first switch tube 104 to be turned on for a long time through the pulse width modulation module 1014, even if the first switch tube 104 is in the on state for a long time, and the first switch 1061 of the pressure relief module 106 is in the on state through the pressure relief module 106, so as to protect the current detection resistor 105.
[0048] At this time, since the first switch tube 104 is in the on state for a long time, the current of the first coil winding 1011 will be relatively large, and the first coil winding 1011 in the saturated state is equivalent to a wire, so that the energy of the first capacitor 103 can be discharged to the ground through the path where the first coil winding 1011, the first switch tube 104 and the first switch 1061 are located, so that the voltage across the first capacitor 103 continues to decrease. Moreover, since the first switch tube 104 is not disconnected at this time, that is, the source and drain of the first switch tube 104 are basically at a low point, the voltage stress is not high, which effectively reduces the risk of the first switch tube 104 being broken down.
[0049] In the process of discharging the energy of the first capacitor 103 through the path where the first coil winding 1011, the first switch tube 104 and the first switch 1061 are located, the voltage across the first capacitor 103 can also be collected in real time through the second voltage acquisition module 108, and when the voltage across the first capacitor 103 is close to the above-mentioned voltage protection threshold V3, the conduction degree of the first switch tube 104 can be adjusted through the pulse width modulation module 1014 to gradually increase the impedance of the first switch tube 104, thereby reducing the degree of energy discharge to the first capacitor 103, and avoiding the first coil winding 1011 from causing a very high peak voltage due to excessive current when the first switch tube 104 is completely disconnected.
[0050] Furthermore, when the voltage across the first capacitor 103 acquired by the second voltage acquisition module 108 is less than the voltage protection threshold V3, the pulse width modulation module 1014 controls the first switch tube 104 to be completely disconnected; at this time, the chip module 109 exits the overvoltage protection state, and the charger resumes the normal charging process; at the same time, the second voltage acquisition module 108 is controlled to resume the closed state to reduce power consumption, and the voltage across the first capacitor 103 is acquired through the third voltage acquisition module 1010.
[0051] In some embodiments, the first switch tube 104 may be a MOS tube, or a GaN tube or a triode.
[0052] In some embodiments, the second switch tube 204 may be a MOS tube, or a GaN tube or a triode.
[0053] An embodiment of the present application also provides a charger, comprising the above-mentioned charging protection circuit.
[0054] It should be noted that the implementation method of the above-mentioned charging protection circuit embodiment is also applicable to the embodiment of the charger and can achieve the same technical effect, which will not be repeated here.
[0055] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0056] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.
Claims
1. A charging protection circuit, characterized in that: include: A power supply, a rectifier module, a first capacitor, a first switching tube, a current detection resistor, and a pressure relief module. The rectifier module is used to convert the AC power output by the power supply into DC power. The first end of the first capacitor is electrically connected to the output end of the rectifier module, and the second end of the first capacitor is grounded. The output end of the rectifier module is also electrically connected to the first end of the current detection resistor via the first switching tube, and the second end of the current detection resistor is grounded. The pressure relief module includes a first switch, the input end of the first switch is electrically connected to the first end of the current detection resistor, and the output end of the first switch is grounded. Wherein, when the voltage of the power supply drops from the first voltage to the first preset voltage, both the first switching tube and the first switch are in the on state.
2. The charging protection circuit according to claim 1, characterized in that: The charging protection circuit further includes a first voltage detection module, wherein the first voltage detection module is used to detect the voltage of the power supply; When the first voltage detection module detects that the voltage of the power supply drops from the first voltage to the first preset voltage, the first switching tube and the first switch are both in the on state.
3. The charging protection circuit according to claim 2, characterized in that: The charging protection circuit further includes a second voltage acquisition module, wherein the second voltage acquisition module is used to acquire the voltage across the first capacitor; When the difference between the voltage across the first capacitor acquired by the second voltage acquisition module and a second preset voltage is smaller than a preset value, the conduction degree of the first switch tube is adjusted to increase the impedance of the first switch tube.
4. The charging protection circuit according to claim 3, characterized in that: The charging protection circuit further includes a chip module, and the second voltage acquisition module and the chip module are integrated.
5. The charging protection circuit according to any one of claims 1 to 4, characterized in that: The charging protection circuit also includes a third voltage acquisition module, a first coil winding, and a second coil winding. The input end of the first coil winding is electrically connected to the output end of the rectifier module, and the output end of the first coil winding is electrically connected to the first end of the current detection resistor through the first switching tube. The first coil winding is coupled to the second coil winding, and the third voltage acquisition module is used to collect the voltage of the second coil winding.
6. The charging protection circuit according to claim 5, characterized in that: The charging protection circuit further includes an overvoltage protection module and a pulse width modulation module, wherein the overvoltage protection module is electrically connected to the third voltage acquisition module and the pulse width modulation module respectively, and the pulse width modulation module is also electrically connected to the gate of the first switching tube; When the voltage of the second coil winding acquired by the third voltage acquisition module is higher than a third preset voltage, the overvoltage protection module sends a control signal to the pulse width modulation module to enable the pulse width modulation module to turn off the first switch tube.
7. The charging protection circuit according to claim 5, characterized in that: The charging protection circuit also includes an upper bias resistor and a lower bias resistor, one end of the second coil winding is grounded, and the other end is electrically connected to the first end of the upper bias resistor, the second end of the upper bias resistor is electrically connected to the first end of the lower bias resistor, the second end of the lower bias resistor is grounded, and the third voltage acquisition module is electrically connected to the second end of the upper bias resistor.
8. The charging protection circuit according to claim 7, characterized in that: The charging protection circuit also includes a first diode and a second capacitor, wherein the anode of the first diode is electrically connected to the first end of the bias resistor, the cathode of the first diode is electrically connected to the first end of the second capacitor, and the second end of the second capacitor is grounded.
9. The charging protection circuit according to any one of claims 1 to 4, characterized in that: The first switch tube is a MOS tube.
10. A charger, characterized in that: The charging protection circuit comprises the charging protection circuit according to any one of claims 1 to 9.