Electric bicycle burglar alarm load switch circuit with rapid overcurrent protection capability

Abstract

The utility model discloses an electric bicycle burglar alarm load switch circuit with rapid overcurrent protection capability, which relates to the field of overcurrent protection circuits and comprises a micro-control module. The driving module is adaptively connected with the switching device Q1, the micro-control module and the load and is used for driving the switching device Q1, and the switching device Q1 is connected between the battery and the load; the overcurrent protection module is adaptively connected with the switching device Q1 and the micro-control module and is used for generating a feedback voltage VFB when an overcurrent phenomenon occurs in the load switching circuit; when an overcurrent phenomenon occurs in the load switching circuit, the micro-control module controls the conduction state of the switching device Q1 through the driving module based on the feedback voltage VFB so as to control the connection state of the battery and the load, and the circuit can realize rapid overcurrent protection.

Description

Technical Field

[0001] The utility model relates to the field of load switch circuits, in particular to an electric bicycle anti-theft device load switch circuit with rapid overcurrent protection capability. Background Art

[0002] As the safety and reliability of electric bicycles are attracting more and more attention from consumers, the reliability of various protection functions of electric bicycle anti-theft devices, as one of the most critical safety accessories among electric bicycle accessories, is also facing increasingly severe challenges. It not only needs to perform conventional protection, but also needs to perform abnormal state protection when the electric bicycle is abnormal.

[0003] The electric bicycle anti-theft device generally uses a load switch circuit to open or close the electrical connection between the electric bicycle battery and the load. When an abnormality occurs in the electric bicycle, the load switch circuit will cause an overcurrent phenomenon. At this time, the electric bicycle anti-theft device controller will control the load switch circuit to close the electrical connection between the battery pack and the load, thereby protecting the circuit in the electric bicycle from damage. Therefore, the electric bicycle anti-theft device load switch circuit with overcurrent protection capability is one of the most important circuits in the abnormal protection circuit that handles sudden abnormalities of electric bicycles.

[0004] Figure 1 The circuit schematic diagram of the conventional electric bicycle anti-theft device load switch circuit is shown in FIG. Figure 1 As shown in the figure, the circuit outputs PWM square wave through the IO2 pin of the single-chip microcomputer to charge the capacitor C1 quickly, so that the NMOS tube Q1 is turned on and the load is powered. When the electric bicycle suddenly malfunctions, the current in the load switch circuit increases, and the IO1 pin of the single-chip microcomputer detects the voltage increase on R1 and determines that the state is an overcurrent state. At this time, the IO2 pin of the single-chip microcomputer stops outputting PWM square wave, and the C1 capacitor cannot be charged, so that the NMOS tube Q1 is turned off, and the battery BAT will no longer supply power to the load through the NMOS tube Q1 to play the role of overcurrent protection. Although this circuit is simple and easy to implement, the time it takes to realize the overcurrent protection action is too slow, and it needs to match a larger power resistor and a larger power NMOS tube to prevent circuit damage. Utility Model Content

[0005] In view of the above problems and technical requirements, the applicant has proposed a load switch circuit of an electric bicycle anti-theft device with fast overcurrent protection capability.

[0006] The technical solution of the utility model is as follows:

[0007] A load switch circuit of an electric bicycle anti-theft device with fast overcurrent protection capability, comprising:

[0008] Microcontroller module;

[0009] A driving module, adapted to be connected with the switch device Q1, the microcontroller module and the load, and used to drive the switch device Q1, wherein the switch device Q1 is connected between the battery and the load;

[0010] An overcurrent protection module is adapted to be connected with the switch device Q1 and the microcontroller module, and is used to generate a feedback voltage VFB when an overcurrent occurs in the load switch circuit;

[0011] When an overcurrent occurs in the load switch circuit, the microcontroller controls the conduction state of the switch device Q1 through the drive module based on the feedback voltage VFB to control the connection state between the battery and the load.

[0012] A further technical solution is that the overcurrent protection module includes a resistor R1, a resistor R3, a resistor R4 and a switch device Q2, wherein:

[0013] One end of the resistor R1 is connected to the positive electrode of the battery, the other end of the resistor R1 is connected to the third electrode end of the switch device Q1, and the first electrode end of the switch device Q1 is connected to the positive electrode of the load;

[0014] The first electrode terminal of the switch device Q2 is connected to one end of the resistor R1, and the second electrode terminal of the switch device Q2 is connected to the other end of the resistor R1;

[0015] The third electrode terminal of the switch device Q2 is connected to the micro-control module through the resistor R3;

[0016] One end of the resistor R4 is connected to the resistor R3 and the micro-control module, and the other end of the resistor R4 is grounded.

[0017] A further technical solution is that the overcurrent protection module further includes a switch device Q3 and a diode D3, wherein:

[0018] The anode of the diode D3 is connected to the first electrode terminal of the switching device Q1 and the positive electrode of the load, the cathode of the diode D3 is connected to the third electrode terminal of the switching device Q3 and the second electrode terminal of the switching device Q1, the second electrode terminal of the switching device Q3 is connected to one end of the resistor R3 and one end of the resistor R4, and the first electrode terminal of the switching device Q3 is grounded.

[0019] A further technical solution is that the driving module includes a capacitor C1, a capacitor C2, a diode D1, a diode D2 and a resistor R2, wherein:

[0020] The cathode of the diode D1 is connected to the microcontroller module via the capacitor C2, and the anode of the diode D1 is connected to the positive electrode of the load and the first electrode end of the switch device Q1;

[0021] The anode of the diode D2 is connected to the cathode of the diode D1, and the cathode of the diode D2 is connected to the anode of the diode D1 by the capacitor C1;

[0022] One end of the resistor R2 is connected to the cathode of the diode D2 and one end of the capacitor C1 , and the other end of the resistor R2 is connected to the positive electrode of the load and the first electrode end of the switch device Q1 .

[0023] Its further technical solution is that the microcontroller module includes an MCU;

[0024] The MCU includes a first signal pin IO1 and a second signal pin IO2, wherein:

[0025] The first signal pin IO1 is connected to the second electrode end of the switch device Q3, one end of the resistor R3 and one end of the resistor R4;

[0026] The second signal pin IO2 is connected to the cathode of the diode D1 and the anode of the diode D2 via the capacitor C2.

[0027] A further technical solution is that the second signal pin IO2 is used to output a driving signal, and the driving signal includes a PWM square wave signal.

[0028] A further technical solution is that the negative electrode of the load and the negative electrode of the battery are connected to one end of the resistor R4 and grounded.

[0029] A further technical solution is that the switch device Q1 includes an NMOS tube or a PMOS tube.

[0030] A further technical solution is that the switch device Q2 includes a PNP transistor.

[0031] A further technical solution is that the switch device Q3 includes an NMOS tube or a PMOS tube.

[0032] The beneficial technical effects of the utility model are:

[0033] The load switch circuit of the electric bicycle anti-theft device provided by the utility model is provided with an overcurrent protection module. The overcurrent protection module generates a feedback voltage VFB when an overcurrent phenomenon occurs in the load switch circuit. The microcontroller module controls the switch device Q1 to turn off through the drive module based on the feedback voltage VFB to disconnect the battery from the load, thereby realizing rapid overcurrent protection. In addition, when the overcurrent protection module includes the switch device Q3 and the diode D3, the diode D3 and the switch device Q3 can further increase the turn-off speed of the switch device Q1, thereby further increasing the speed of the overcurrent protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1It is the circuit schematic diagram of the load switch circuit of the traditional electric bicycle anti-theft device.

[0035] Figure 2 The utility model provides a circuit principle diagram of a load switch circuit of an electric bicycle anti-theft device with rapid overcurrent protection capability. DETAILED DESCRIPTION

[0036] The specific implementation of the utility model is further described below in conjunction with the accompanying drawings.

[0037] The utility model provides a load switch circuit of an electric bicycle anti-theft device with fast overcurrent protection capability, comprising:

[0038] Microcontroller module;

[0039] A driving module, adapted to be connected with the switch device Q1, the microcontroller module and the load, and used to drive the switch device Q1, wherein the switch device Q1 is connected between the battery and the load;

[0040] An overcurrent protection module is adapted to be connected with the switch device Q1 and the microcontroller module, and is used to generate a feedback voltage VFB when an overcurrent occurs in the load switch circuit;

[0041] When an overcurrent occurs in the load switch circuit, the microcontroller controls the conduction state of the switch device Q1 through the drive module based on the feedback voltage VFB to control the connection state between the battery and the load.

[0042] Specifically, the overcurrent phenomenon in the load switch circuit refers to the phenomenon that the current in the load switch circuit exceeds the preset current due to reasons such as load short circuit. The large current will not only damage the circuit components, but also cause the circuit components to overheat and cause safety hazards. Therefore, it is very important to enable the load switch circuit to have a fast overcurrent protection capability.

[0043] In one embodiment of the utility model, the switch device Q1 is connected between the battery and the load. When the switch device Q1 is turned on, the battery is connected to the load through the switch device Q1, and the battery supplies power to the load; conversely, when the switch device Q1 is turned off, the battery is disconnected from the load, and the battery stops supplying power to the load. Therefore, the utility model can control the connection relationship between the battery and the load by controlling the conduction state of the switch device Q1. The specific connection method of the battery, the switch device Q1 and the load can refer to the following description. When an overcurrent phenomenon occurs in the load switch circuit, the micro-control module controls the conduction state of the switch device Q1 through the drive module based on the feedback voltage VFB, which specifically refers to the micro-control module controlling the drive module according to the feedback voltage VFB, and controlling the switch device Q1 to turn off through the drive module, so that the battery is disconnected from the load, and rapid overcurrent protection is achieved. The specific structure and adaptive connection method of the above-mentioned micro-control module, drive module and overcurrent protection module can refer to the following description.

[0044] Furthermore, the overcurrent protection module includes a resistor R1, a resistor R3, a resistor R4 and a switch device Q2, wherein:

[0045] One end of the resistor R1 is connected to the positive electrode of the battery, the other end of the resistor R1 is connected to the third electrode end of the switch device Q1, and the first electrode end of the switch device Q1 is connected to the positive electrode of the load;

[0046] The first electrode terminal of the switch device Q2 is connected to one end of the resistor R1, and the second electrode terminal of the switch device Q2 is connected to the other end of the resistor R1;

[0047] The third electrode terminal of the switch device Q2 is connected to the micro-control module through the resistor R3;

[0048] One end of the resistor R4 is connected to the resistor R3 and the micro-control module, and the other end of the resistor R4 is grounded.

[0049] Optionally, the switch device Q1 may be a PMOS transistor or an NMOS transistor, and the switch device Q2 may be a PNP transistor. Since the cost of a PMOS transistor is usually higher than that of an NMOS transistor, preferably, the switch device Q2 is an NMOS transistor.

[0050] The overcurrent protection module generates a feedback voltage VFB when an overcurrent occurs in the load switch circuit. Specifically, when an overcurrent occurs, the current flowing through the resistor R1 increases, and the voltage difference across the resistor R1 increases, thereby turning on the switch device Q2, and the resistor R3 and the resistor R4 divide the voltage to generate the feedback voltage VFB.

[0051] Furthermore, the overcurrent protection module further includes a switch device Q3 and a diode D3, wherein:

[0052] The anode of the diode D3 is connected to the first electrode terminal of the switching device Q1 and the positive electrode of the load, the cathode of the diode D3 is connected to the third electrode terminal of the switching device Q3 and the second electrode terminal of the switching device Q1, the second electrode terminal of the switching device Q3 is connected to one end of the resistor R3 and one end of the resistor R4, and the first electrode terminal of the switching device Q3 is grounded.

[0053] Optionally, the switch device Q3 may be a PMOS tube or an NMOS tube. Similar to the above, since the cost of a PMOS tube is usually higher than that of an NMOS tube, preferably, the switch device Q3 also adopts an NMOS tube. When the overcurrent protection module includes the switch device Q3 and the diode D3, when an overcurrent phenomenon occurs in the circuit, the diode D3 and the switch device Q3 can further increase the turn-off speed of the switch device Q1, thereby further increasing the speed of the overcurrent protection. The specific principle of the diode D3 and the switch device Q3 further increasing the turn-off speed of the switch device Q1 can be referred to the following description.

[0054] Figure 2 The circuit schematic diagram of the load switch circuit is shown when the switch device Q1 is an NMOS tube, the switch device Q2 is a PNP triode, and the switch device Q3 is an NMOS tube. It should be noted that when the switch device Q1 is an NMOS tube, the first electrode terminal of the switch device Q1 is the source terminal, the second electrode terminal of the switch device Q1 is the gate terminal, and the third electrode terminal of the switch device Q1 is the drain terminal. When the switch device Q2 is a PNP triode, the first electrode terminal of the switch device Q2 is the emitter terminal, the second electrode terminal of the switch device Q2 is the base terminal, and the third electrode terminal of the switch device Q2 is the collector terminal. When the switch device Q3 is an NMOS tube, the first electrode terminal of the switch device Q3 is the source terminal, the second electrode terminal of the switch device Q3 is the gate terminal, and the third electrode terminal of the switch device Q3 is the drain terminal.

[0055] like Figure 2 As shown, in this embodiment, the source terminal of the switching device Q1 is connected to the positive electrode of the load, one end of the resistor R2 and the anode of the diode D3, the gate terminal of the switching device Q1 is connected to the cathode of the diode D3 and the drain terminal of the switching device Q3, the drain terminal of the switching device Q1 is connected to the base terminal of the switching device Q2, and the drain of the switching device Q1 is connected to the positive electrode of the battery through the resistor R1. The emitter terminal of the switching device Q2 is connected to one end of the resistor R1 and the positive electrode of the battery, the base terminal of the switching device Q2 is connected to the other end of the resistor R1, the collector terminal of the switching device Q2 is connected to one end of the resistor R3, one end of the resistor R3 is connected to the gate terminal of the switching device Q3, the source terminal of the switching device Q3 is grounded, and the negative electrode of the load and the negative electrode of the battery are connected to one end of the resistor R4 and grounded.

[0056] Furthermore, the driving module includes a capacitor C1, a capacitor C2, a diode D1, a diode D2 and a resistor R2, wherein:

[0057] The cathode of the diode D1 is connected to the microcontroller module via the capacitor C2, and the anode of the diode D1 is connected to the positive electrode of the load and the first electrode end of the switch device Q1;

[0058] The anode of the diode D2 is connected to the cathode of the diode D1, and the cathode of the diode D2 is connected to the anode of the diode D1 by the capacitor C1;

[0059] One end of the resistor R2 is connected to the cathode of the diode D2 and one end of the capacitor C1 , and the other end of the resistor R2 is connected to the positive electrode of the load and the first electrode end of the switch device Q1 .

[0060] The microcontroller module includes an MCU;

[0061] The MCU includes a first signal pin IO1 and a second signal pin IO2, wherein:

[0062] The first signal pin IO1 is connected to the second electrode end of the switch device Q3, one end of the resistor R3 and one end of the resistor R4, and the first signal pin is used to receive the feedback voltage VFB;

[0063] The second signal pin IO2 is connected to the cathode of the diode D1 and the anode of the diode D2 via the capacitor C2. The second signal pin IO2 is used to output a driving signal, and the driving signal includes a PWM square wave signal.

[0064] Specifically, the capacitor C1, the capacitor C2, the diode D1 and the diode D2 in the driving module constitute a charge pump circuit. Under the drive signal, the capacitor C1 in the charge pump circuit is quickly charged, thereby driving the switch device Q1 to turn on, the battery is indirectly connected to the load, and the load is powered. In one embodiment of the utility model, the drive signal is a 20KHZ PWM square wave signal with a peak-to-peak value of 5V. The output state of the drive signal output by the second signal pin IO2 is determined by the voltage level of the first signal pin IO1. When the load switch circuit is in a normal working state, that is, when there is no overcurrent phenomenon, the overcurrent protection module does not generate a feedback voltage VFB, the first signal pin IO1 is at a low voltage, and the second signal pin IO2 outputs a drive signal. When an overcurrent phenomenon occurs in the load switch circuit, the overcurrent protection module generates a feedback voltage VFB and loads it to the first signal pin IO1, the first signal pin IO1 is at a high voltage, and the second signal pin IO2 stops outputting the drive signal.

[0065] The specific working principle of the load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability provided by the utility model is:

[0066] When the load switch circuit is in normal working state, that is, when there is no overcurrent phenomenon, the first signal pin IO1 is at a low voltage, and the second signal pin IO2 outputs a driving signal. The capacitor C1 is quickly charged under the driving signal, thereby driving the switch device Q1 to turn on, and the battery is indirectly connected to the load, and the load is powered.

[0067] When the load switch circuit has an overcurrent phenomenon, the current flowing through the resistor R1 increases, and the voltage difference across the resistor R1 increases, thereby turning on the switch device Q2. The resistor R3 and the resistor R4 divide the voltage to generate the feedback voltage VFB. The feedback voltage VFB is loaded to the first signal pin IO1 of the MCU, the first signal pin IO1 is a high voltage, the second signal pin IO2 stops outputting the drive signal, the capacitor C1 discharges through the resistor R2, and the switch device Q1 starts to turn off. At the same time, the high voltage of the first signal pin IO1 is loaded to the switch device Q3, turning on the switch device Q3. The diode D3 and the switch device Q3 quickly pull down the voltage of the gate terminal and the source terminal of the switch device Q1 to the ground potential, further improving the turn-off speed of the switch device Q1, so that the switch device Q1 is quickly turned off, and the battery and the load are quickly disconnected, realizing fast overcurrent protection.

[0068] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A load switch circuit for an electric bicycle anti-theft device with fast overcurrent protection capability, characterized in that: include: Microcontroller module; A driving module, adapted to be connected with the switch device Q1, the microcontroller module and the load, and used to drive the switch device Q1, wherein the switch device Q1 is connected between the battery and the load; An overcurrent protection module is adapted to be connected with the switch device Q1 and the microcontroller module, and is used to generate a feedback voltage VFB when an overcurrent occurs in the load switch circuit; When an overcurrent occurs in the load switch circuit, the microcontroller controls the conduction state of the switch device Q1 through the drive module based on the feedback voltage VFB to control the connection state between the battery and the load.

2. The load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability according to claim 1 is characterized in that: The overcurrent protection module includes a resistor R1, a resistor R3, a resistor R4 and a switch device Q2, wherein: One end of the resistor R1 is connected to the positive electrode of the battery, the other end of the resistor R1 is connected to the third electrode end of the switch device Q1, and the first electrode end of the switch device Q1 is connected to the positive electrode of the load; The first electrode terminal of the switch device Q2 is connected to one end of the resistor R1, and the second electrode terminal of the switch device Q2 is connected to the other end of the resistor R1; The third electrode terminal of the switch device Q2 is connected to the micro-control module through the resistor R3; One end of the resistor R4 is connected to the resistor R3 and the micro-control module, and the other end of the resistor R4 is grounded.

3. The load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability according to claim 2 is characterized in that: The overcurrent protection module also includes a switch device Q3 and a diode D3, wherein: The anode of the diode D3 is connected to the first electrode terminal of the switching device Q1 and the positive electrode of the load, the cathode of the diode D3 is connected to the third electrode terminal of the switching device Q3 and the second electrode terminal of the switching device Q1, the second electrode terminal of the switching device Q3 is connected to one end of the resistor R3 and one end of the resistor R4, and the first electrode terminal of the switching device Q3 is grounded.

4. The load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability according to claim 3 is characterized in that: The driving module includes a capacitor C1, a capacitor C2, a diode D1, a diode D2 and a resistor R2, wherein: The cathode of the diode D1 is connected to the microcontroller module via the capacitor C2, and the anode of the diode D1 is connected to the positive electrode of the load and the first electrode end of the switch device Q1; The anode of the diode D2 is connected to the cathode of the diode D1, and the cathode of the diode D2 is connected to the anode of the diode D1 by the capacitor C1; One end of the resistor R2 is connected to the cathode of the diode D2 and one end of the capacitor C1 , and the other end of the resistor R2 is connected to the positive electrode of the load and the first electrode end of the switch device Q1 .

5. The load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability according to claim 4 is characterized in that: The microcontroller module includes an MCU; The MCU includes a first signal pin IO1 and a second signal pin IO2, wherein: The first signal pin IO1 is connected to the second electrode end of the switch device Q3, one end of the resistor R3 and one end of the resistor R4; The second signal pin IO2 is connected to the cathode of the diode D1 and the anode of the diode D2 via the capacitor C2.

6. The load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability according to claim 5 is characterized in that: The second signal pin IO2 is used to output a driving signal, and the driving signal includes a PWM square wave signal.

7. The load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability according to claim 1 is characterized in that: The negative electrode of the load and the negative electrode of the battery are connected to one end of the resistor R4 and grounded.

8. The load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability according to claim 1 is characterized in that: The switch device Q1 includes an NMOS tube or a PMOS tube.

9. The load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability according to claim 2, characterized in that: The switch device Q2 includes a PNP transistor.

10. The load switch circuit of the electric bicycle anti-theft device with fast overcurrent protection capability according to claim 3 is characterized in that: The switch device Q3 includes an NMOS tube or a PMOS tube.

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