Charging protection circuit

Abstract

The utility model provides a charging protection circuit which comprises a power supply end, a first switch unit, a control unit, a second switch unit, a variable resistance unit and a voltage stabilizing unit. According to the embodiment of the invention, the variable resistance unit and the voltage stabilizing unit are arranged, when the overvoltage of the load is applied to the variable resistance unit, the voltage stabilizing unit is broken down, and the second controlled end of the second switch unit is electrically connected with the voltage stabilizing unit, so that the second switch unit is switched on, and the detection end detects the voltage change; the control unit controls the first switch unit to be switched off through the control end based on the voltage change so as to protect the charging circuit, and due to the arrangement of the variable resistance unit, different voltage limiting values are set through the change of the resistance of the variable resistance unit.

Description

Technical Field

[0001] The utility model relates to the technical field of electronics, and in particular to a charging protection circuit. Background Art

[0002] Existing power supply circuits are prone to occasional overvoltage conditions. Therefore, to prevent damage to the load's battery and shorten its lifespan, it is usually necessary to implement voltage limiting in the circuit. However, if the loads have different charging power models, adjusting the voltage limit requires the use of a high-cost overvoltage chip.

[0003] Therefore, how to provide a low-cost charging protection circuit that can adjust the voltage limit value. Utility Model Content

[0004] In order to solve the above problems, the present invention proposes: a charging protection circuit, including a power supply end, a first switch unit and a control unit, wherein a first input end of the first switch unit is electrically connected to the power supply end, a first output end of the first switch unit is electrically connected to a load, and a first controlled end of the first switch unit is electrically connected to a control end of the control unit, and the circuit further includes:

[0005] a second switch unit, wherein a second input end of the second switch unit is electrically connected to the detection end of the control unit, and a second output end of the second switch unit is electrically connected to the ground end;

[0006] a variable resistance unit, wherein a first connection end of the variable resistance unit is electrically connected to the first output end, and a second connection end of the variable resistance unit is electrically connected to the ground end;

[0007] A voltage stabilizing unit, one end of which is electrically connected to the second controlled end of the second switch unit, and the other end of which is electrically connected to the active end of the resistance changing unit.

[0008] Beneficial effects:

[0009] The present invention provides a variable resistance unit and a voltage stabilizing unit. When an overvoltage from a load is applied to the variable resistance unit, the voltage stabilizing unit breaks down. Since the second controlled terminal of the second switch unit is electrically connected to the voltage stabilizing unit, the second switch unit is turned on. The detection terminal detects a voltage change, and the control unit controls the first switch unit to disconnect based on the voltage change, thereby protecting the charging circuit. Furthermore, due to the provision of the variable resistance unit, different voltage limits can be set by varying the resistance of the variable resistance unit. Therefore, the present invention provides a hardware architecture that can help protect circuits from overvoltage conditions and cost-effectively adjust the circuit's voltage limit.

[0010] Furthermore, the variable resistance unit includes an eighth resistor and an adjustable resistor, the first end of the eighth resistor is electrically connected to the first output end, the second end of the eighth resistor is electrically connected to the first fixed end of the adjustable resistor, the second fixed end of the adjustable resistor is electrically connected to the ground end, and the adjustment end of the adjustable resistor is electrically connected to the voltage stabilizing unit.

[0011] Furthermore, the first switching unit includes a third resistor, a fourth resistor and a second transistor, the first end of the fourth resistor is electrically connected to the control end of the control unit, the second end of the fourth resistor is electrically connected to the first end of the third resistor and the base of the second transistor, the emitter of the second transistor is electrically connected to the power supply end, and the collector of the second transistor is electrically connected to the load.

[0012] Furthermore, the second switching unit includes a first transistor, the collector of the first transistor is electrically connected to the power supply end, the base of the first transistor is electrically connected to one end of the voltage stabilizing unit away from the resistance changing unit, and the emitter of the first transistor is electrically connected to the ground end.

[0013] Furthermore, the circuit further includes a return resistor, a first end of the return resistor is electrically connected to the load and the first output end of the first switch unit, and a second end of the return resistor is electrically connected to the ground end.

[0014] Furthermore, the circuit further includes:

[0015] a charging unit, wherein a first end of the charging unit is electrically connected to the power supply end, the detection end of the control unit, and the power supply end, and a second end of the charging unit is electrically connected to the ground end;

[0016] A third switch unit, wherein the third input end of the third switch unit is electrically connected to the first end of the charging unit, the third output end of the third switch unit is electrically connected to the ground end, and the third controlled end of the third switch unit is electrically connected to the second end of the return resistor.

[0017] Furthermore, the third switching unit includes a seventh resistor and a third transistor, the collector of the third transistor is electrically connected to the first end of the charging unit, the emitter of the third transistor is electrically connected to the ground end and the first end of the seventh resistor, and the base of the third transistor is electrically connected to the second end of the seventh resistor and the ground end.

[0018] Furthermore, the third switch unit further includes a sixth resistor, a first end of the sixth resistor being electrically connected to the base of the third transistor, and a second end of the sixth resistor being electrically connected to the second end of the seventh resistor and the ground end.

[0019] Furthermore, the circuit further includes an alarm unit, a first end of the alarm unit is electrically connected to the driving end of the control unit, and a second end of the alarm unit is electrically connected to the ground end.

[0020] Furthermore, the alarm unit includes a light emitting diode, an anode of the light emitting diode is electrically connected to the driving end of the control unit, and a cathode of the light emitting diode is electrically connected to the ground end. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0022] Figure 1 A circuit diagram of a charging protection circuit provided by the utility model;

[0023] Figure 2 This is a circuit diagram of a charging protection circuit according to another embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It will be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some, rather than all, structures related to the present application are shown in the accompanying drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0025] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of this application, "plurality" means two or more, unless otherwise specifically specified.

[0027] In this specification, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0028] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0029] The utility model provides a charging protection circuit, including a power supply terminal 1, a first switch unit 2 and a control unit 4, wherein a first input terminal 21 of the first switch unit 2 is electrically connected to the power supply terminal 1, a first output terminal 22 of the first switch unit 2 is electrically connected to a load 3, and a first controlled terminal 23 of the first switch unit 2 is electrically connected to a control terminal 41 of the control unit 4. The circuit further includes:

[0030] a second switch unit 6 , wherein a second input terminal 61 of the second switch unit 6 is electrically connected to the detection terminal 42 of the control unit 4 , and a second output terminal 63 of the second switch unit 6 is electrically connected to the ground terminal 9 ;

[0031] a variable resistance unit 7, wherein a first connection end 71 of the variable resistance unit 7 is electrically connected to the first output end 22, and a second connection end 73 of the variable resistance unit 7 is electrically connected to the ground end 9;

[0032] The voltage stabilizing unit 10 has one end electrically connected to the second controlled end 62 of the second switch unit 6 , and the other end electrically connected to the active end 73 of the resistance changing unit 7 .

[0033] This embodiment provides a variable resistance unit 7 and a voltage stabilizing unit 10. When an overvoltage from the load 2 is applied to the variable resistance unit 7, the voltage stabilizing unit 10 will break down. Since the second controlled terminal 62 of the second switch unit 6 is electrically connected to the voltage stabilizing unit 10, the second switch unit 6 is turned on, and the detection terminal 42 detects a voltage change. Based on the voltage change, the control unit 4 controls the first switch unit 2 to be disconnected via the control terminal 41, thereby protecting the charging circuit. Furthermore, due to the provision of the variable resistance unit 7, different voltage limit values can be set by changing the resistance of the variable resistance unit 7. Therefore, the present invention provides a hardware architecture that can help protect circuits from overvoltage conditions and adjust the circuit's voltage limit value at a low cost.

[0034] It should be noted that by adjusting the resistance of the resistance variable unit 7 , the voltage output to the voltage stabilizing unit 10 from different power supply voltages can be made the same, and different voltage stabilization values can achieve the same breakdown effect.

[0035] Preferably, if Figure 2 As shown, the variable resistance unit includes an eighth resistor and an adjustable resistor, the first end of the eighth resistor is electrically connected to the first output end 22, the second end of the eighth resistor is electrically connected to the first fixed end of the adjustable resistor, the second fixed end of the adjustable resistor is electrically connected to the ground end 9, and the adjustment end of the adjustable resistor is electrically connected to the voltage stabilizing unit 10.

[0036] Specifically, the eighth resistor is Figure 2 The R8 in the figure is the CW in Figure 2. The adjustable resistor can be a device with adjustable resistance value such as a sliding resistor or a potentiometer, such as Figure 2 As shown, by changing the sliding end of the adjustable resistor CW, the voltage limit value of the circuit can be adjusted at a low cost.

[0037] Preferably, the first switching unit 2 includes a third resistor, a fourth resistor and a second transistor, the first end of the fourth resistor is electrically connected to the control end 41 of the control unit 4, the second end of the fourth resistor is electrically connected to the first end of the third resistor and the base of the second transistor, the emitter of the second transistor is electrically connected to the power supply end 1, and the collector of the second transistor is electrically connected to the load 3.

[0038] Specifically, the third resistor is Figure 2 The fourth resistor is R3 in Figure 2 The R4 in the second transistor is Figure 2 Q2 in the control unit 4, the control terminal 41 of the control unit 4 is Figure 2 The control terminal 41 of the control unit 4 can control the voltage value output to the base of the second transistor Q2, thereby controlling the conduction and cutoff of the second transistor Q2.

[0039] Preferably, the second switching unit 6 includes a first transistor, the collector of the first transistor is electrically connected to the power supply terminal 1, the base of the first transistor is electrically connected to the end of the voltage stabilizing unit 10 away from the variable resistance unit 7, and the emitter of the first transistor is electrically connected to the ground terminal 9.

[0040] Specifically, the first transistor is Q1 in Figure 2. When the voltage stabilizing unit 10 is broken, the base of the first transistor Q1 is energized, so that the first transistor Q1 is turned on. When the voltage stabilizing unit 10 is not broken, the base of the first transistor Q1 is de-energized, so that the first transistor Q1 is turned off.

[0041] Preferably, the circuit further comprises a return resistor, a first end of the return resistor is electrically connected to the load 3 and the first output end 22 of the first switch unit 2, and a second end of the return resistor is electrically connected to the ground end.

[0042] Specifically, the reflux resistor is Figure 2 When the circuit is just powered on, the first switch unit 2 is turned on, most of the current passes through the resistor RL to form a loop, and a small part of the current passes through the variable resistance unit 7 to form a loop.

[0043] Preferably, the circuit further comprises:

[0044] a charging unit 5, wherein a first end of the charging unit 5 is electrically connected to the power supply terminal 1, the detection terminal 42 of the control unit 4, and the power supply terminal 1, and a second end of the charging unit 5 is electrically connected to the ground terminal 9;

[0045] A third switching unit, wherein the third input end of the third switching unit is electrically connected to the first end of the charging unit 5, the third output end of the third switching unit is electrically connected to the ground end 9, and the third controlled end of the third switching unit is electrically connected to the second end of the return resistor.

[0046] In this embodiment, a charging unit 5 is provided. When the circuit is just powered on, the power supply terminal 1 charges the charging unit 5. When the detection terminal 42 detects that the voltage of the charging unit 5 is greater than a certain voltage value, the control unit 4 controls the first switch unit 2 to be turned on, and most of the current forms a loop through the resistor RL, and a small part of the current forms a loop through the variable resistance unit 7. When the current of the load 3 increases, the third switch unit is turned on, causing the voltage value detected by the detection terminal 42 to be lowered to less than a certain voltage value. The control unit 4 controls the first switch unit 2 to be turned off, and the power supply terminal 1 is disconnected from the load 3. Since the power supply terminal 1 will continue to charge the charging unit 5 until the current on the load drops to a normal value, the circuit achieves overcurrent protection for the load 3.

[0047] Specifically, if Figure 2As shown, the charging unit 5 can be a third capacitor C3, the power supply terminal 1 charges the third capacitor C3 through the fifth resistor R5, and the detection terminal 42 of the control unit 4 can be Figure 2 Pin 6 and / or pin 2 of the middle chip U1.

[0048] Preferably, the third switching unit includes a seventh resistor and a third transistor, the collector of the third transistor is electrically connected to the first end of the charging unit 5, the emitter of the third transistor is electrically connected to the ground end 9 and the first end of the seventh resistor, and the base of the third transistor is electrically connected to the second end of the seventh resistor and the ground end 9.

[0049] Specifically, the seventh resistor is Figure 2 The third transistor is R7 in Figure 2 When the current of the load 3 increases, the voltage on the seventh resistor R7 increases to a certain value, and the third transistor Q3 is turned on.

[0050] Preferably, the third switching unit further includes a sixth resistor, a first end of the sixth resistor is electrically connected to the base of the third transistor, and a second end of the sixth resistor is electrically connected to the second end of the seventh resistor and the ground terminal 9 .

[0051] Preferably, the circuit further includes an alarm unit, a first end of the alarm unit is electrically connected to the driving end of the control unit 4 , and a second end of the alarm unit is electrically connected to the ground end 9 .

[0052] When there is overcurrent or overvoltage in the circuit, the driving end of the control unit 4 can drive the alarm unit to be powered and alarm to remind the user that there is overcurrent and overvoltage. The alarm unit can be a light emitting diode, a buzzer, etc.

[0053] Specifically, if Figure 2 As shown, the alarm unit includes a light-emitting diode, the anode of the light-emitting diode is electrically connected to the driving end of the control unit 4, and the cathode of the light-emitting diode is electrically connected to the ground terminal 9. The light-emitting diode is D1 in the figure, and the driving end of the control unit 4 is pin 3 of the chip U1, which can drive the brightness of the light-emitting diode D1.

[0054] It should be noted that terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or vertical, but rather that they may be slightly tilted. Terms such as "parallel" and "perpendicular" do not imply that components are absolutely parallel or perpendicular to each other, but rather that a certain angle deviation may be formed. For example, "horizontal" simply means that its direction is more horizontal than "vertical" and does not mean that the structure must be completely horizontal, but rather that it may be slightly tilted. Furthermore, terms such as "center," "longitudinal," "transverse," "length," "width," "thickness," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," and "counterclockwise" indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships typically used when the products of this application are used. These terms are used solely to facilitate the description of the embodiments of this application and to simplify the description, and do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0055] It is understood that the meaning of "plurality" herein is at least two, such as two, three, etc., unless there is a special limitation. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units that are inherent to these processes, methods, products or devices. The term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the related objects before and after are in an "or" relationship.

[0056] The above description is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A charging protection circuit, comprising a power supply terminal (1), a first switch unit (2) and a control unit (4), wherein a first input terminal (21) of the first switch unit (2) is electrically connected to the power supply terminal (1), a first output terminal (22) of the first switch unit (2) is electrically connected to a load (3), and a first controlled terminal (23) of the first switch unit (2) is electrically connected to a control terminal (41) of the control unit (4), characterized in that: The circuit further comprises: a second switch unit (6), wherein a second input terminal (61) of the second switch unit (6) is electrically connected to the detection terminal (42) of the control unit (4), and a second output terminal (63) of the second switch unit (6) is electrically connected to the ground terminal (9); A variable resistance unit (7), wherein a first connection end (71) of the variable resistance unit (7) is electrically connected to the first output end (22), and a second connection end (73) of the variable resistance unit (7) is electrically connected to the ground end (9); A voltage stabilizing unit (10), one end of the voltage stabilizing unit (10) being electrically connected to the second controlled end (62) of the second switch unit (6), and the other end of the voltage stabilizing unit (10) being electrically connected to the active end (72) of the resistance changing unit (7).

2. A charging protection circuit according to claim 1, characterized in that: The variable resistance unit includes an eighth resistor and an adjustable resistor, wherein the first end of the eighth resistor is electrically connected to the first output end (22), the second end of the eighth resistor is electrically connected to the first fixed end of the adjustable resistor, the second fixed end of the adjustable resistor is electrically connected to the ground end (9), and the adjustment end of the adjustable resistor is electrically connected to the voltage stabilizing unit (10).

3. The charging protection circuit according to claim 1, wherein: The first switch unit (2) comprises a third resistor, a fourth resistor and a second triode, wherein the first end of the fourth resistor is electrically connected to the control end (41) of the control unit (4), the second end of the fourth resistor is electrically connected to the first end of the third resistor and the base of the second triode, the emitter of the second triode is electrically connected to the power supply end (1), and the collector of the second triode is electrically connected to the load (3).

4. The charging protection circuit according to claim 1, wherein: The second switch unit (6) includes a first transistor, the collector of the first transistor is electrically connected to the power supply terminal (1), the base of the first transistor is electrically connected to an end of the voltage stabilizing unit (10) away from the resistance changing unit (7), and the emitter of the first transistor is electrically connected to the ground terminal (9).

5. The charging protection circuit according to claim 1, wherein: The circuit further comprises a return resistor, wherein a first end of the return resistor is electrically connected to the load (3) and the first output end (22) of the first switch unit (2), and a second end of the return resistor is electrically connected to the ground end.

6. A charging protection circuit according to claim 5, characterized in that: The circuit further comprises: a charging unit (5), wherein a first end of the charging unit (5) is electrically connected to the power supply end (1), the detection end (42) of the control unit (4), and the power supply end (1), and a second end of the charging unit (5) is electrically connected to the ground end (9); A third switch unit, wherein a third input terminal of the third switch unit is electrically connected to the first terminal of the charging unit (5), a third output terminal of the third switch unit is electrically connected to the ground terminal (9), and a third controlled terminal of the third switch unit is electrically connected to the second terminal of the return resistor.

7. A charging protection circuit according to claim 6, characterized in that: The third switch unit comprises a seventh resistor and a third triode, the collector of the third triode is electrically connected to the first end of the charging unit (5), the emitter of the third triode is electrically connected to the ground end (9) and the first end of the seventh resistor, and the base of the third triode is electrically connected to the second end of the seventh resistor and the ground end (9).

8. A charging protection circuit according to claim 7, characterized in that: The third switch unit further includes a sixth resistor, a first end of the sixth resistor being electrically connected to the base of the third transistor, and a second end of the sixth resistor being electrically connected to the second end of the seventh resistor and the ground terminal (9).

9. A charging protection circuit according to any one of claims 1 to 8, characterized in that: The circuit further comprises an alarm unit, a first end of the alarm unit being electrically connected to the driving end of the control unit (4), and a second end of the alarm unit being electrically connected to the ground end (9).

10. A charging protection circuit according to claim 9, characterized in that: The alarm unit comprises a light emitting diode, the anode of the light emitting diode is electrically connected to the driving end of the control unit (4), and the cathode of the light emitting diode is electrically connected to the grounding end (9).

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