A switching circuit

Abstract

The utility model discloses a kind of switching circuits, comprising: switching module, current detection module, overload protection module;Switching module's first input terminal input control signal, switching module's second input terminal input input voltage, switching module's first output terminal is connected with the input terminal of current detection module, switching module's second output terminal exports output voltage, the output terminal of current detection module is connected with the first input terminal of overload protection module, the output terminal of overload protection module is connected with the third input terminal of switching module, switching module's second output terminal is connected with the second input terminal of overload protection module, the third input terminal of overload protection module input control signal.The response speed of the switching circuit overload protection is fast.

Description

Technical Field

[0001] This application relates to the field of switching circuit technology, and more specifically, to a switching circuit. Background Technology

[0002] Traditional switching circuits, especially simple ones, often lack effective overload protection mechanisms. When the load current exceeds the rated value (e.g., due to a load short circuit or an abnormally large current load being connected), the switching element may overheat and be damaged due to overcurrent, potentially leading to a safety accident.

[0003] Some system-level solutions (such as fuses and circuit breakers) can provide overload protection for switching circuits, but these solutions are often slow to respond, require manual intervention for reset, or have low integration, increasing system complexity and cost. If the switch is not open, the front-end input is not activated, and the back-end load has been powered on via another path, current may flow in reverse through the switching circuit, back from the load to the input, causing unknown damage.

[0004] Existing technology discloses a MOSFET switching circuit. The MOSFET switching circuit includes a MOSFET Q1, a transistor Q2, and a voltage regulator D1. The collector of transistor Q2 is connected to the power input terminal V_IN and the gate of MOSFET Q1, the emitter of transistor Q2 is grounded, and the base of transistor Q2 is connected to the control signal terminal ON_OFF_SWITCH. The source of MOSFET Q1 is connected to the power input terminal V_IN, and the drain of MOSFET Q1 is connected to the power output terminal V_OUT. The voltage regulator D1 is connected between the source and gate of MOSFET Q1. This scheme does not consider the case of reverse current flowing through the switching circuit and lacks overload protection measures for the switching circuit. Utility Model Content

[0005] This invention addresses the shortcomings of existing technologies that provide slow response speeds for overload protection in switching circuits by providing a new switching circuit with fast overload protection response speed.

[0006] A switching circuit includes: a switching module, a current detection module, and an overload protection module; The first input terminal of the switch module receives a control signal, the second input terminal receives an input voltage, the first output terminal of the switch module is connected to the input terminal of the current detection module, the second output terminal of the switch module outputs an output voltage, the output terminal of the current detection module is connected to the first input terminal of the overload protection module, the output terminal of the overload protection module is connected to the third input terminal of the switch module, the second output terminal of the switch module is connected to the second input terminal of the overload protection module, and the third input terminal of the overload protection module receives a control signal.

[0007] Furthermore, the switching module includes: a first MOSFET Q1, a second MOSFET Q2, and a transistor Q3; The input voltage is input to the second terminal of the first MOSFET Q1, the control signal is input to the base of the transistor Q3, the emitter of the transistor Q3 is grounded, the first terminal of the first MOSFET Q1 and the first terminal of the second MOSFET Q2 are connected to the collector of the transistor Q3, the third terminal of the first MOSFET Q1 is connected to the third terminal of the second MOSFET Q2, the second terminal of the second MOSFET Q2 outputs the output voltage, the second terminal of the second MOSFET Q2 is connected to the input terminal of the current detection module, and the output terminal of the overload protection module is connected to the base of the transistor Q3.

[0008] Furthermore, the switching module also includes: a first capacitor C1, an eleventh resistor R11, a fourth resistor R4, a first resistor R1, and a second resistor R2; The control signal is input to one end of the eleventh resistor R11. The other end of the eleventh resistor R11 is connected to one end of the fourth resistor R4 and the base of the transistor Q3. The other end of the fourth resistor R4 is grounded. One end of the second resistor R2 is connected to the collector of the transistor Q3. The other end of the second resistor R2 is connected to one end of the first capacitor C1, one end of the first resistor R1, and the first end of the first MOSFET Q1. The other end of the first capacitor C1 is connected to the other end of the first resistor R1 and the second end of the first MOSFET Q1.

[0009] Furthermore, the switching module also includes a second capacitor C2, one end of which is connected to the base of the transistor Q3, and the other end of which is grounded.

[0010] Furthermore, the current detection module includes: a ninth resistor R9 and an operational amplifier; One end of the ninth resistor R9 is connected to the first output terminal of the switching module and the first input terminal of the operational amplifier, and the other end of the ninth resistor R9 is connected to the second input terminal of the operational amplifier; the second input terminal of the operational amplifier is connected to the second input terminal of the overload protection module, and the output terminal of the operational amplifier is connected to the first input terminal of the overload protection module.

[0011] Furthermore, the current detection module also includes: a fifth resistor R5, a seventh resistor R7, and a sixth resistor R6; One end of the fifth resistor R5 is connected to one end of the ninth resistor R9, and the other end of the fifth resistor R5 is connected to the first input terminal of the operational amplifier. One end of the seventh resistor R7 is connected to the other end of the ninth resistor R9, and the other end of the seventh resistor R7 is connected to the second input terminal of the operational amplifier. The first input terminal of the operational amplifier is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is grounded.

[0012] Furthermore, the overload protection module includes: a comparator, a twelfth resistor R12, and an eighth resistor R8; The second output terminal of the current detection module is connected to one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to one end of the twelfth resistor R12 and the first output terminal of the current detection module. The other end of the twelfth resistor R12 is connected to the second input terminal of the comparator. The first input terminal of the comparator receives the control signal.

[0013] Furthermore, the overload protection module also includes: diode D1 and tenth resistor R10; One end of the tenth resistor R10 is connected to the output of the comparator, and the other end of the tenth resistor R10 is connected to the negative terminal of diode D1. The positive terminal of diode D1 is connected to the third input terminal of the switching module.

[0014] Furthermore, it also includes a third capacitor C3; The second output terminal of the switch module is connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is grounded.

[0015] Furthermore, it also includes a fourth capacitor C4 and a fifth capacitor C5; The second output terminal of the switch module is connected to one end of the fourth capacitor C4 and the fifth capacitor C5, and the other end of the fourth capacitor C4 and the fifth capacitor C5 is grounded.

[0016] Compared with the prior art, the beneficial effects of this utility model are: This invention adds a current detection module and an overload protection module. When the load current is too large and may damage the components, the current detection module and the overload protection module can shut off the switching circuit in time, thereby effectively protecting the components at the front and back ends of the circuit. Attached Figure Description

[0017] Figure 1 The schematic diagram of a switching circuit provided in Example 1 is shown.

[0018] Figure 2 The circuit structure diagram of the switching module provided in Example 1; Figure 3 This is a structural diagram of a switching circuit provided in Example 1. Detailed Implementation

[0019] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.

[0020] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0021] Example 1 like Figure 1 As shown, a switching circuit includes: a switching module, a current detection module, and an overload protection module; The first input terminal of the switch module receives a control signal, the second input terminal receives an input voltage, the first output terminal of the switch module is connected to the input terminal of the current detection module, the second output terminal of the switch module outputs an output voltage, the output terminal of the current detection module is connected to the first input terminal of the overload protection module, the output terminal of the overload protection module is connected to the third input terminal of the switch module, the second output terminal of the switch module is connected to the second input terminal of the overload protection module, and the third input terminal of the overload protection module receives a control signal.

[0022] Furthermore, such as Figure 2 As shown, the switching module includes: a first MOSFET Q1, a second MOSFET Q2, and a transistor Q3; The input voltage is input to the second terminal of the first MOSFET Q1, the control signal is input to the base of the transistor Q3, the emitter of the transistor Q3 is grounded, the first terminal of the first MOSFET Q1 and the first terminal of the second MOSFET Q2 are connected to the collector of the transistor Q3, the third terminal of the first MOSFET Q1 is connected to the third terminal of the second MOSFET Q2, the second terminal of the second MOSFET Q2 outputs the output voltage, the second terminal of the second MOSFET Q2 is connected to the input terminal of the current detection module, and the output terminal of the overload protection module is connected to the base of the transistor Q3.

[0023] This invention, by setting a first MOSFET and a second MOSFET, prevents current from flowing back from the rear to the front when the rear load is powered on first, thus preventing current from flowing in reverse through the switching circuit.

[0024] In one specific embodiment, the first MOSFET Q1 and the second MOSFET Q2 are two p-channel MOSFETs, respectively.

[0025] Furthermore, the switching module also includes: a first capacitor C1, an eleventh resistor R11, a fourth resistor R4, a first resistor R1, and a second resistor R2; The control signal is input to one end of the eleventh resistor R11. The other end of the eleventh resistor R11 is connected to one end of the fourth resistor R4 and the base of the transistor Q3. The other end of the fourth resistor R4 is grounded. One end of the second resistor R2 is connected to the collector of the transistor Q3. The other end of the second resistor R2 is connected to one end of the first capacitor C1, one end of the first resistor R1, and the first end of the first MOSFET Q1. The other end of the first capacitor C1 is connected to the other end of the first resistor R1 and the second end of the first MOSFET Q1.

[0026] In one specific embodiment, the first capacitor C1 is 100nF and the eleventh resistor R11 is 10K. The fourth resistor R4 is 10K. The first resistor R1 is 100 kΩ. The second resistor R2 is 10K. .

[0027] Furthermore, the switching module also includes a second capacitor C2, one end of which is connected to the base of the transistor Q3, and the other end of which is grounded.

[0028] In one specific embodiment, the second capacitor C2 is 47. .

[0029] Furthermore, the current detection module includes: a ninth resistor R9 and an operational amplifier; One end of the ninth resistor R9 is connected to the first output terminal of the switching module and the first input terminal of the operational amplifier, and the other end of the ninth resistor R9 is connected to the second input terminal of the operational amplifier; the second input terminal of the operational amplifier is connected to the second input terminal of the overload protection module, and the output terminal of the operational amplifier is connected to the first input terminal of the overload protection module.

[0030] In one specific embodiment, the ninth resistor is 0.1R. .

[0031] Furthermore, the current detection module also includes: a fifth resistor R5, a seventh resistor R7, and a sixth resistor R6; One end of the fifth resistor R5 is connected to one end of the ninth resistor R9, and the other end of the fifth resistor R5 is connected to the first input terminal of the operational amplifier. One end of the seventh resistor R7 is connected to the other end of the ninth resistor R9, and the other end of the seventh resistor R7 is connected to the second input terminal of the operational amplifier. The first input terminal of the operational amplifier is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is grounded.

[0032] In one specific embodiment, the fifth resistor R5 is 10K. The seventh resistor R7 is 10K. The sixth resistor R6 is 33K. .

[0033] Furthermore, the overload protection module includes: a comparator, a twelfth resistor R12, and an eighth resistor R8; The second output terminal of the current detection module is connected to one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to one end of the twelfth resistor R12 and the first output terminal of the current detection module. The other end of the twelfth resistor R12 is connected to the second input terminal of the comparator. The first input terminal of the comparator receives the control signal.

[0034] In one specific embodiment, the twelfth resistor R12 is 100R. The eighth resistor, R8, is 33K. .

[0035] Furthermore, the overload protection module also includes: diode D1 and tenth resistor R10; One end of the tenth resistor R10 is connected to the output of the comparator, and the other end of the tenth resistor R10 is connected to the negative terminal of diode D1. The positive terminal of diode D1 is connected to the third input terminal of the switching module.

[0036] In one specific embodiment, the tenth resistor R10 is 10R. .

[0037] It should be noted that the overload protection module uses an RC circuit (including resistor R10 and diode D1) to achieve a delay. When the current exceeds the threshold, the comparator quickly turns off the switch. After the switch is turned off, the comparator returns to a high-level output, and the high-level input from the control module is used to delay the switch back on via the RC circuit.

[0038] Furthermore, it also includes a third capacitor C3; The second output terminal of the switch module is connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is grounded.

[0039] Furthermore, it also includes a fourth capacitor C4 and a fifth capacitor C5; The second output terminal of the switch module is connected to one end of the fourth capacitor C4 and the fifth capacitor C5, and the other end of the fourth capacitor C4 and the fifth capacitor C5 is grounded.

[0040] In one specific embodiment, the third capacitor C3 is 10. The fourth capacitor C4 is 100n. The fifth capacitor C5 is 1n. .

[0041] like Figure 3As shown, this invention adds a current detection module and an overload protection module. When the load current is too high and may damage components, the current detection module and overload protection module can promptly shut off the switching circuit, thereby effectively protecting the components at both the front and rear ends of the circuit. The front end of the circuit in this invention refers to the voltage input (Vin). The rear end of the circuit in this invention refers to the voltage output (Vout).

[0042] In one specific embodiment, the voltage input Vin = 12V. When the control signal (Vcontrol) is low, transistor Q3 is off, and the first MOSFET Q1 and the second MOSFET Q2 are turned off, thus opening the switch. When the control signal (Vcontrol) is high, transistor Q3 is on, and the first MOSFET Q1 and the second MOSFET Q2 are on, opening the switch. When the switch is not open and the downstream load is powered on first, the second MOSFET Q2 will prevent current backflow through the body diode. When the switch is normally open, if the downstream load current exceeds 10A, a voltage drop of more than 1V will be formed across the ninth resistor R9. The operational amplifier outputs 3.3 times the voltage across the ninth resistor R9 through the subtraction circuit (the amplification factor can be changed by changing the values ​​of the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8, thereby setting different current protection thresholds). The comparator compares the amplifier output voltage with the control signal (Vcontrol) (3.3V in this invention, but other values ​​can also be input) and outputs a low level. The base voltage of transistor Q3 is quickly pulled low through the comparator output (the pull-down time in this circuit design is approximately 0.5ms, which can be adjusted by changing the second capacitor C2 and the tenth resistor R10), thus turning off the switch protection circuit. After turning off, wait approximately 0.5s (the wait time can be adjusted by changing the second capacitor C2 and the eleventh resistor R11) before turning the switch back on to achieve automatic recovery.

[0043] The same or similar labels correspond to the same or similar parts; The terms used to describe positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A switching circuit, characterized in that, include: Switching module, current detection module, overload protection module; The first input terminal of the switch module receives a control signal, the second input terminal receives an input voltage, the first output terminal of the switch module is connected to the input terminal of the current detection module, the second output terminal of the switch module outputs an output voltage, the output terminal of the current detection module is connected to the first input terminal of the overload protection module, the output terminal of the overload protection module is connected to the third input terminal of the switch module, the second output terminal of the switch module is connected to the second input terminal of the overload protection module, and the third input terminal of the overload protection module receives a control signal.

2. The switching circuit according to claim 1, characterized in that, The switching module includes: a first MOSFET Q1, a second MOSFET Q2, and a transistor Q3; The input voltage is input to the second terminal of the first MOSFET Q1, the control signal is input to the base of the transistor Q3, the emitter of the transistor Q3 is grounded, the first terminal of the first MOSFET Q1 and the first terminal of the second MOSFET Q2 are connected to the collector of the transistor Q3, the third terminal of the first MOSFET Q1 is connected to the third terminal of the second MOSFET Q2, the second terminal of the second MOSFET Q2 outputs the output voltage, the second terminal of the second MOSFET Q2 is connected to the input terminal of the current detection module, and the output terminal of the overload protection module is connected to the base of the transistor Q3.

3. The switching circuit according to claim 2, characterized in that, The switching module further includes: a first capacitor C1, an eleventh resistor R11, a fourth resistor R4, a first resistor R1, and a second resistor R2; The control signal is input to one end of the eleventh resistor R11. The other end of the eleventh resistor R11 is connected to one end of the fourth resistor R4 and the base of the transistor Q3. The other end of the fourth resistor R4 is grounded. One end of the second resistor R2 is connected to the collector of the transistor Q3. The other end of the second resistor R2 is connected to one end of the first capacitor C1, one end of the first resistor R1, and the first end of the first MOSFET Q1. The other end of the first capacitor C1 is connected to the other end of the first resistor R1 and the second end of the first MOSFET Q1.

4. A switching circuit according to claim 2 or 3, characterized in that, The switching module also includes a second capacitor C2, one end of which is connected to the base of the transistor Q3, and the other end of which is grounded.

5. The switching circuit according to claim 1, characterized in that, The current detection module includes: a ninth resistor R9 and an operational amplifier; One end of the ninth resistor R9 is connected to the first output terminal of the switching module and the first input terminal of the operational amplifier, and the other end of the ninth resistor R9 is connected to the second input terminal of the operational amplifier; the second input terminal of the operational amplifier is connected to the second input terminal of the overload protection module, and the output terminal of the operational amplifier is connected to the first input terminal of the overload protection module.

6. The switching circuit according to claim 5, characterized in that, The current detection module also includes: a fifth resistor R5, a seventh resistor R7, and a sixth resistor R6; One end of the fifth resistor R5 is connected to one end of the ninth resistor R9, and the other end of the fifth resistor R5 is connected to the first input terminal of the operational amplifier. One end of the seventh resistor R7 is connected to the other end of the ninth resistor R9, and the other end of the seventh resistor R7 is connected to the second input terminal of the operational amplifier. The first input terminal of the operational amplifier is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is grounded.

7. A switching circuit according to claim 6, characterized in that, The overload protection module includes: a comparator, a twelfth resistor R12, and an eighth resistor R8; The second output terminal of the current detection module is connected to one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to one end of the twelfth resistor R12 and the first output terminal of the current detection module. The other end of the twelfth resistor R12 is connected to the second input terminal of the comparator. The first input terminal of the comparator receives the control signal.

8. The switching circuit according to claim 7, characterized in that, The overload protection module also includes: diode D1 and tenth resistor R10; One end of the tenth resistor R10 is connected to the output of the comparator, and the other end of the tenth resistor R10 is connected to the negative terminal of diode D1. The positive terminal of diode D1 is connected to the third input terminal of the switching module.

9. A switching circuit according to claim 1, characterized in that, It also includes the third capacitor C3; The second output terminal of the switch module is connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is grounded.

10. A switching circuit according to claim 1, characterized in that, It also includes the fourth capacitor C4 and the fifth capacitor C5; The second output terminal of the switch module is connected to one end of the fourth capacitor C4 and the fifth capacitor C5, and the other end of the fourth capacitor C4 and the fifth capacitor C5 is grounded.

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