Bicycle derailleur protection system and method

Abstract

The application discloses a bicycle derailleur protection system and method, and relates to the technical field of bicycle derailleurs. The method comprises the following steps: a rear derailleur is provided with a first main control chip and a rear derailleur protection circuit, and the first main control chip is provided with a first communication serial port; a front derailleur is provided with a second main control chip and a front derailleur protection circuit, and the second main control chip is provided with a second communication serial port; a power supply communication cable is electrically connected to the first communication serial port through the rear derailleur protection circuit at one end, and is electrically connected to the second communication serial port through the front derailleur protection circuit at the other end; the power supply communication cable is provided with a communication line and a power line, the power line is used for providing a power supply voltage for the rear derailleur and the front derailleur, and the communication line is used for communication between the rear derailleur and the front derailleur. The bicycle derailleur protection system can protect the front derailleur and the rear derailleur from short circuit, and avoid damaging the main control chip.

Description

Technical Field

[0001] This invention relates to the field of bicycle derailleur technology, and in particular to a bicycle derailleur protection system and method. Background Technology

[0002] The electronic derailleur system of a bicycle mainly consists of a front derailleur and a rear derailleur. The front and rear derailleurs rely on a power communication line (wire sequence defined as: VCC, GND, UART-TXD, UART-RXD) to transmit power and communication signals. The power supply is typically provided by two or three lithium batteries, with a voltage of 8.4V to 12.6V. The communication signal, UART, uses TTL / CMOS levels from the main chip of the front and rear derailleurs, typically 3.3V or 5V. If a short circuit occurs in the wiring (e.g., due to frame friction causing insulation damage or wire bending leading to an internal short circuit), the high voltage will be directly applied to the communication signals of the front and rear derailleurs, directly impacting the main control chip and causing permanent damage. For an electronic derailleur system, this hardware damage is irreversible, causing significant harm to product functionality and performance stability, affecting market reputation and user experience, and in severe cases, potentially leading to accidents and personal injury during riding. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a bicycle derailleur protection system and method capable of providing short-circuit protection for the front and rear derailleurs, preventing damage to the main chip.

[0004] In a first aspect, a bicycle derailleur protection system according to an embodiment of the present invention includes:

[0005] The rear derailleur has a first main control chip and a rear derailleur protection circuit, and the first main control chip has a first communication serial port.

[0006] The front derailleur has a second main control chip and a front derailleur protection circuit, and the second main control chip has a second communication serial port.

[0007] A power communication cable is provided, one end of which is electrically connected to the first communication serial port through the rear derailleur protection circuit, and the other end of which is electrically connected to the second communication serial port through the front derailleur protection circuit. The power communication cable has a communication line and a power line. The power line is used to provide power voltage to the rear derailleur and the front derailleur, and the communication line is used to enable communication between the rear derailleur and the front derailleur.

[0008] Specifically, when the rear derailleur and the front derailleur are communicating normally, the rear derailleur protection circuit is used to perform level conversion on the signals received or transmitted by the rear derailleur, and the front derailleur protection circuit is used to perform level conversion on the signals received or transmitted by the front derailleur; when the power line and the communication line are short-circuited, the rear derailleur protection circuit isolates the first communication serial port from the power communication cable, and the front derailleur protection circuit isolates the second communication serial port from the power communication cable.

[0009] According to some embodiments of the present invention, the first communication serial port includes a first transmitting serial port and a first receiving serial port, the second communication serial port includes a second transmitting serial port and a second receiving serial port, the rear derailleur protection circuit includes a first protection circuit and a second protection circuit, the first transmitting serial port is electrically connected to the first protection circuit, the first receiving serial port is electrically connected to the second protection circuit, the front derailleur protection circuit includes a third protection circuit and a fourth protection circuit, the second transmitting serial port is electrically connected to the third protection circuit, and the second receiving serial port is electrically connected to the fourth protection circuit.

[0010] According to some embodiments of the present invention, the first protection circuit includes a first MOSFET, the source of the first MOSFET is electrically connected to the first transmitting serial port, the source of the first MOSFET is also connected to the system power supply of the rear derailleur through a first pull-up resistor, the gate of the first MOSFET is electrically connected to the system power supply of the rear derailleur, the drain of the first MOSFET is connected to the power supply voltage through a second pull-up resistor, the drain of the first MOSFET is also electrically connected to one end of the power communication cable, and a first parasitic diode is provided between the source and drain of the first MOSFET.

[0011] According to some embodiments of the present invention, the first protection circuit further includes a first current-limiting resistor, which is disposed between the first transmitting serial port and the source of the first MOS transistor, and a second parasitic diode is provided between the source and drain of the second MOS transistor.

[0012] According to some embodiments of the present invention, the second protection circuit includes a second MOS transistor, the source of the second MOS transistor is electrically connected to the first receiving serial port, the source of the second MOS transistor is also connected to the system power supply of the rear derailleur through a third pull-up resistor, the gate of the second MOS transistor is electrically connected to the system power supply of the rear derailleur, and the drain of the second MOS transistor is electrically connected to one end of the power communication cable.

[0013] According to some embodiments of the present invention, the second protection circuit further includes a second current-limiting resistor, which is disposed between the first receiving serial port and the source of the second MOS transistor.

[0014] According to some embodiments of the present invention, the third protection circuit includes a third MOS transistor, the source of which is electrically connected to the second transmitting serial port, the source of which is also connected to the system power supply of the front derailleur via a fourth pull-up resistor, the gate of which is electrically connected to the system power supply of the front derailleur, the drain of which is connected to the power supply voltage via a fifth pull-up resistor, the drain of which is also electrically connected to the other end of the power communication cable, and a third parasitic diode between the source and drain of the third MOS transistor.

[0015] According to some embodiments of the present invention, the fourth protection circuit includes a fourth MOS transistor, the source of which is electrically connected to the second receiving serial port, the source of which is also connected to the system power supply of the front derailleur through a sixth pull-up resistor, the gate of which is electrically connected to the system power supply of the front derailleur, the drain of which is electrically connected to the other end of the power communication cable, and a fourth parasitic diode between the source and drain of the fourth MOS transistor.

[0016] According to some embodiments of the present invention, the third protection circuit further includes a third current-limiting resistor disposed between the second transmitting serial port and the source of the third MOS transistor, and the fourth protection circuit further includes a fourth current-limiting resistor disposed between the second receiving serial port and the source of the fourth MOS transistor.

[0017] Secondly, according to an embodiment of the present invention, a bicycle derailleur protection method is applied to a bicycle derailleur protection system as described in the first aspect embodiment, the method comprising:

[0018] When the front derailleur communicates with the rear derailleur, a first signal is sent to the rear derailleur protection circuit through the first communication serial port of the first main control chip; the rear derailleur protection circuit performs level conversion on the first signal and sends the level-converted first signal to the front derailleur protection circuit through the power communication cable; the front derailleur protection circuit performs secondary level conversion on the level-converted first signal and sends the secondary level-converted first signal to the second communication serial port of the second main control chip;

[0019] Alternatively, a second signal may be sent to the front derailleur protection circuit via the second communication serial port of the second main control chip; the front derailleur protection circuit may perform level conversion on the second signal and send the level-converted second signal to the rear derailleur protection circuit via the power communication cable; the rear derailleur protection circuit may perform secondary level conversion on the level-converted second signal and send the secondary level-converted second signal to the first communication serial port of the first main control chip;

[0020] When the power line and communication line of the power communication cable are short-circuited, the first communication serial port is isolated from the power communication cable by the rear derailleur protection circuit, and the second communication serial port is isolated from the power communication cable by the front derailleur protection circuit.

[0021] The bicycle derailleur protection system and method according to embodiments of the present invention have at least the following beneficial effects: by setting a rear derailleur protection circuit between the first main control chip of the rear derailleur and the power communication cable, and by setting a front derailleur protection circuit between the second main control chip of the front derailleur and the power communication cable, the power and communication signals at the cable end are isolated from the communication level of the main control chip on the PCB board. When a short circuit occurs in the power and communication signals of the cable, the board can react quickly and isolate the short circuit fault at the cable end without affecting the communication signal on the board, thus protecting the main control chip from high voltage surges. Simultaneously, it can be easily integrated into the compact space of the derailleur without increasing power consumption and at a low cost.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 This is a schematic diagram of the structure of a bicycle derailleur protection system according to an embodiment of the present invention;

[0025] Figure 2 This is a flowchart illustrating the steps of a bicycle derailleur protection method according to an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram illustrating the short-circuit protection principle of a bicycle gearbox protection system according to an embodiment of the present invention. Detailed Implementation

[0027] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0028] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0029] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0030] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0031] The electronic derailleur system of a bicycle mainly consists of a front derailleur and a rear derailleur. The front and rear derailleurs rely on a power communication line (wire sequence defined as: VCC, GND, UART-TXD, UART-RXD) to transmit power and communication signals. The power supply is typically provided by two or three lithium batteries, with a voltage of 8.4V to 12.6V. The communication signal, UART, uses TTL / CMOS levels from the main chip of the front and rear derailleurs, typically 3.3V or 5V. If a short circuit occurs in the wiring (e.g., due to frame friction causing insulation damage or wire bending leading to an internal short circuit), the high voltage will be directly applied to the communication signals of the front and rear derailleurs, directly impacting the main control chip and causing permanent damage. For an electronic derailleur system, this hardware damage is irreversible, causing significant harm to product functionality and performance stability, affecting market reputation and user experience, and in severe cases, potentially leading to accidents and personal injury during riding.

[0032] Currently, the main protection solutions for bicycle derailleurs are as follows:

[0033] Fuse: It needs to be replaced after it blows, resulting in high maintenance costs; its response speed is slow (millisecond level), and it cannot protect sensitive chips.

[0034] Self-resetting fuses (PPTC): have long recovery times, affecting system real-time performance; they also have slow response times (milliseconds), making them unable to protect sensitive chips; and they are relatively large, making them difficult to integrate into compact bicycle derailleurs.

[0035] Diode / Zenith diode clamping: It only limits voltage and cannot cut off current. Continuous short circuits can still cause the chip to overheat. At the same time, diodes will have leakage current. During normal communication without short circuits, continuous leakage current will increase system power consumption.

[0036] Isolation chips: Dedicated isolation chips are large in size, making them difficult to integrate into compact self-propelled gearbox circuit boards, and they are also expensive, which makes them less competitive in terms of product price.

[0037] Optocoupler chips: They can achieve communication signal isolation, but they are easily affected by ambient temperature, causing communication signal distortion. In high or low temperature environments, communication failures are very likely to occur. Moreover, optocoupler chip circuits are relatively expensive.

[0038] In summary, it is clear that existing solutions cannot simultaneously meet the following requirements in bicycle derailleur scenarios: rapid interruption of short-circuit voltage / current (microsecond-level response); adaptive power supply voltage fluctuations (compatible with 8.4V~12.6V power supply); isolation of power supply voltage and chip I / O port communication level (TTL level 3.3V / 5V); miniaturization, integration, and reduced component count (adapting to the space constraints of bicycle derailleurs); no increase in overall power consumption; and low cost, offering a cost-performance advantage.

[0039] Therefore, embodiments of the present invention provide a bicycle derailleur protection system and method that can quickly cut off short-circuit voltage / current, adapt to power supply voltage fluctuations, isolate the power supply voltage from the communication level of the chip's I / O port (TTL level 3.3V / 5V); it is miniaturized, integrated, and reduces the number of components (adapting to the space constraints of bicycle derailleurs); it does not increase the overall power consumption and has low cost, giving it a cost-performance advantage.

[0040] The bicycle derailleur protection system and method of the present invention will now be described in detail with reference to the accompanying drawings.

[0041] On the one hand, embodiments of the present invention propose a bicycle gearbox protection system, such as Figure 1 As shown, the system includes:

[0042] The rear derailleur has a first main control chip MCU1 and a rear derailleur protection circuit. The first main control chip MCU1 has a first communication serial port (TXD / RXD).

[0043] The front derailleur has a second main control chip MCU2 and a front derailleur protection circuit. The second main control chip MCU2 has a second communication serial port (TXD / RXD).

[0044] The power communication cable has one end electrically connected to the first communication serial port through the rear derailleur protection circuit, and the other end electrically connected to the second communication serial port through the front derailleur protection circuit. The power communication cable has communication lines (UART-TXD, UART-RXD) and power lines (VCC, GND). The power lines are used to provide the power voltage VBAT to the rear and front derailleurs, and the communication lines are used for communication between the rear and front derailleurs.

[0045] Specifically, when the rear derailleur and the front derailleur are communicating normally, the rear derailleur protection circuit is used to perform level conversion on the signals received or sent by the rear derailleur, and the front derailleur protection circuit is used to perform level conversion on the signals received or sent by the front derailleur; when the power line and the communication line are short-circuited, the rear derailleur protection circuit isolates the first communication serial port from the power communication cable, and the front derailleur protection circuit isolates the second communication serial port from the power communication cable.

[0046] This bicycle derailleur protection system isolates the power and communication signals at the cable ends from the communication levels of the main control chips on the PCB board by setting up a rear derailleur protection circuit between the first main control chip MCU1 on the rear derailleur and the power communication cable, and a front derailleur protection circuit between the second main control chip MCU2 on the front derailleur and the power communication cable. When a short circuit occurs in the power or communication signal of the cable, the board can quickly react and isolate the short circuit fault at the cable end without affecting the board's communication signal, protecting the main control chip from high voltage surges. Furthermore, it can be easily integrated into the compact space of the derailleur without increasing power consumption and at a low cost.

[0047] like Figure 1 As shown, in some embodiments of this application, the first communication serial port includes a first transmitting serial port (TXD) and a first receiving serial port (RXD). The rear derailleur protection circuit includes a first protection circuit and a second protection circuit. The first transmitting serial port is electrically connected to the first protection circuit, and the first receiving serial port is electrically connected to the second protection circuit. Specifically, the first protection circuit includes a first MOSFET Q2. The source of the first MOSFET Q2 is electrically connected to the first transmitting serial port. The source of the first MOSFET Q2 is also connected to the system power supply VCC1 (3.3V or 5V) of the rear derailleur through a first pull-up resistor R1. The gate of the first MOSFET Q2 is electrically connected to the system power supply VCC1 of the rear derailleur. The drain of the first MOSFET Q2 is connected to the power supply voltage VBAT (7.4V~12.6V) through a second pull-up resistor R2. The drain of the first MOSFET Q2 is also electrically connected to one end of a power communication cable. A first parasitic diode is present between the source and drain of the first MOSFET Q2. A level conversion circuit is formed by a first MOSFET Q2, a first pull-up resistor R1, and a second pull-up resistor R2. The source of the first MOSFET Q2 is connected to the TXD port of the first main control chip MCU1 to receive communication signals sent from the first main control chip MCU1. This communication signal is then sent to the power communication cable after passing through the level conversion circuit, and then transmitted to the front derailleur. Due to the presence of the second pull-up resistor R2, the signal level of the serial communication is converted from VCC1 (3.3V or 5V) to VBAT (7.4V~12.6V), thereby achieving the level conversion function.

[0048] Correspondingly, in the front derailleur, the second communication serial port of the second main control chip MCU2 includes a second transmit serial port (TXD) and a second receive serial port (RXD). The front derailleur protection circuit includes a third protection circuit and a fourth protection circuit. The second transmit serial port is electrically connected to the third protection circuit, and the second receive serial port is electrically connected to the fourth protection circuit. Specifically, the fourth protection circuit includes a fourth MOSFET Q3. The source of the fourth MOSFET Q3 is electrically connected to the second receive serial port. The source of the fourth MOSFET Q3 is also connected to the system power supply VCC2 (3.3V or 5V) of the front derailleur through a sixth pull-up resistor R8. The gate of the fourth MOSFET Q3 is electrically connected to the system power supply VCC2 of the rear derailleur. The drain of the fourth MOSFET Q3 is electrically connected to the other end of the power communication cable. A fourth parasitic diode is located between the source and drain of the fourth MOSFET Q3. A level-shifting circuit composed of the fourth MOSFET Q3 and the sixth pull-up resistor R8 converts the communication signal sent from the rear derailleur. After passing through the level-shifting circuit at the receiving end of the front derailleur, the signal is sent to the RXD port of the second main control chip MCU2, thus providing the communication signal to MCU2. This communication signal, after passing through the level-shifting circuit of the front derailleur (composed of the fourth MOSFET Q3 and the sixth pull-up resistor R8), is converted into the system power supply VCC2 (3.3V or 5V).

[0049] When the rear derailleur communicates with the front derailleur, when the first main control chip MCU1 of the rear derailleur sends a high level, the source voltage of the first MOSFET Q2 is pulled up to the system power supply VCC1 (3.3V or 5V) by the first pull-up resistor R1. Therefore, the gate-source voltage V of the first MOSFET Q2... GS =0V, the first MOSFET Q2 is cut off, and the communication line is pulled up to VBAT (7.4V~12.6V) by the second pull-up resistor R2, transmitting a high-level signal (7.4V~12.6V) on the communication line. At this time, the receiver of the front derailleur receives a high-level signal (7.4V~12.6V), which is higher than the source voltage of the fourth MOSFET Q3 (3.3V or 5V). Since the gate and source of the fourth MOSFET Q3 are pulled up to VCC2 (3.3V or 5V) by the sixth pull-up resistor R8, V GS =0V, the fourth MOSFET Q3 is cut off, and the high-level signal on the communication line cannot pass through the fourth MOSFET Q3. Therefore, the RXD port of the second main control chip MCU2 detects a high level signal (3.3V or 5V). So the signal received by the front derailleur is high level (3.3V or 5V).

[0050] When the first main control chip MCU1 of the rear derailleur sends a low level, a voltage difference is generated between the gate and source of the first MOSFET Q2, V GS ≈3.3V or 5V > V th(Cutoff voltage), the first MOSFET Q2 is turned on, and the voltage on the communication line is pulled low by the low-level signal, transmitting a low-level signal (0~0.3V) on the communication line. At this time, the receiver of the front derailleur receives a low-level signal (0~0.3V), because V GS =0V, the fourth MOSFET Q3 was originally cut off; however, due to the presence of the parasitic diode (source to drain) of the fourth MOSFET Q3, the low-side voltage is clamped to 0.7V (diode voltage drop); at this time V GS ≈3.3V - 0.7V = 2.6V > V th (Or: VGS≈5V-0.7V=4.3V>Vth), the fourth MOSFET Q3 is fully turned on, further pulling the low-voltage side down to near 0V. Therefore, the RXD port of the second main control chip MCU2 detects a low level signal (0~0.3V), so the signal received by the front derailleur is low level.

[0051] Correspondingly, the second protection circuit includes a second MOSFET Q4. The source of the second MOSFET Q4 is electrically connected to the first receiving serial port. The source of the second MOSFET Q4 is also connected to the system power supply of the rear derailleur through a third pull-up resistor R7. The gate of the second MOSFET Q4 is electrically connected to the system power supply of the rear derailleur. The drain of the second MOSFET Q4 is electrically connected to one end of the power communication cable. A second parasitic diode is provided between the source and drain of the second MOSFET Q4. The third protection circuit includes a third MOSFET Q1. The source of the third MOSFET Q1 is electrically connected to the second transmitting serial port. The source of the third MOSFET Q1 is also connected to the system power supply VCC2 (3.3V or 5V) of the front derailleur through a fourth pull-up resistor R4. The gate of the third MOSFET Q1 is electrically connected to the system power supply VCC2 of the front derailleur. The drain of the third MOSFET Q1 is connected to the power supply voltage VBAT (7.4V~12.6V) through a fifth pull-up resistor R3. The drain of the third MOSFET Q1 is also electrically connected to the other end of the power communication cable. There is a third parasitic diode between the source and drain of the third MOSFET Q1.

[0052] When the rear derailleur communicates with the front derailleur, the second main control chip MCU2 of the front derailleur sends a high level. At this time, the source voltage of the third MOSFET Q1 is pulled up to the system power supply VCC2 (3.3V or 5V) by the fourth pull-up resistor R4. Therefore, the gate-source voltage V of the third MOSFET Q1... GS=0V, the third MOSFET Q1 is cut off, and the communication line is pulled up to VBAT (7.4V~12.6V) by the fifth pull-up resistor R3, transmitting a high-level signal (7.4V~12.6V) on the communication line. At this time, the receiver of the rear derailleur receives a high-level signal (7.4V~12.6V), which is higher than the source voltage of the second MOSFET Q4 (3.3V or 5V). Since the gate and source of the second MOSFET Q4 are pulled up to VCC1 (3.3V or 5V) by the third pull-up resistor R7, V GS =0V, the second MOSFET Q4 is cut off, and the high-level signal on the communication line cannot pass through the second MOSFET Q4. Therefore, the RXD port of the first main control chip MCU1 detects a high-level signal (3.3V or 5V). So the signal received by the rear derailleur is high-level (3.3V or 5V).

[0053] When the second main control chip MCU2 of the current derailleur sends a low level, a voltage difference is generated between the gate and source of the third MOSFET Q1, V GS ≈3.3V or 5V > V th (Cutoff voltage), the third MOSFET Q1 is turned on, and the voltage on the communication line is pulled low by the low-level signal, transmitting a low-level signal (0~0.3V) on the communication line. At this time, the receiver of the rear derailleur receives a low-level signal (0~0.3V), because V GS =0V, the second MOSFET Q4 was originally cut off; however, due to the presence of the parasitic diode (source to drain) of the second MOSFET Q4, the low-side voltage is clamped to 0.7V (diode voltage drop); at this time V GS ≈3.3V - 0.7V = 2.6V > V th (Or: VGS≈5V-0.7V=4.3V>Vth), the second MOSFET Q4 is fully turned on, further pulling the low-voltage side down to near 0V. Therefore, the RXD port of the second main control chip MCU2 detects a low level signal (0~0.3V), so the signal received by the rear derailleur is low.

[0054] Furthermore, in some embodiments of this application, the first protection circuit further includes a first current-limiting resistor R5, which is disposed between the first transmitting serial port and the source of the first MOSFET Q2. The second protection circuit further includes a second current-limiting resistor R9, which is disposed between the first receiving serial port and the source of the second MOSFET Q4. The third protection circuit further includes a third current-limiting resistor R6, which is disposed between the second transmitting serial port and the source of the third MOSFET Q1. The fourth protection circuit further includes a fourth current-limiting resistor R10, which is disposed between the second receiving serial port and the source of the fourth MOSFET Q3. The first current-limiting resistor R5, the second current-limiting resistor R9, the third current-limiting resistor R6, and the fourth current-limiting resistor R10 serve to limit current.

[0055] It should be noted that communication between the front and rear derailleurs can be achieved via a UART serial communication interface, and the two derailleurs share a common power supply. This power supply can be a lithium battery, consisting of 2 or 3 lithium-ion batteries in series, with a voltage of 7.4V~12.6V. The power communication cable is a 4-core cable with an external insulating sheath. The 4-core cable includes a power line (VCC), a GND line, and two communication lines. The TXD port of MCU1 communicates with the RXD port of MCU2 through one of the communication lines, and the TXD port of MCU2 communicates with the RXD port of MCU1 through the other communication line.

[0056] When a short circuit occurs between the communication line and the power line, the source voltage of the first MOSFET Q2 surges to VBAT (7.4V~12.6V), and the gate-source voltage V... GS = VCC1 - VBAT (e.g., 3.3V - 12.6V = -9.3V), far below the threshold voltage (Vth ≥ -0.7V), the first MOSFET Q2 is instantly turned off, physically isolating the high-voltage path; other MOSFETs are turned off according to the same principle. Furthermore, coordinated protection is provided by the first current-limiting resistor R5, the second current-limiting resistor R9, the third current-limiting resistor R6, and the fourth current-limiting resistor R10. The short-circuit current is limited to ≤30mA by 5 / R10 (typically 100Ω), preventing MOSFET breakdown. Utilizing V during a short circuit... GS The negative voltage characteristic enables "zero detection delay shutdown" without the need for an additional comparator circuit.

[0057] When the rear and front derailleurs are not in operation and are in standby mode, both MCU1 and MCU2 enter standby mode. The software sets the communication serial port TXD / RXD to a high level. At this time, the resistors R2 / R3 (high-voltage side pull-up resistors of the communication line) and R1 / R4 / R7 / R8 (low-voltage side pull-up resistors of the board) are both at a high level. The resistors do not consume power, and the MOSFETs are all in the off state, so they do not consume any power. According to actual testing, this level conversion / protection circuit does not add any extra energy consumption when the entire system is in standby mode and not communicating.

[0058] Therefore, the bicycle derailleur protection system according to the embodiments of this application has the following advantages:

[0059] ① Bidirectional multiplexing design: The same MOSFET simultaneously performs level conversion and short-circuit protection functions, breaking through the traditional circuit's single function;

[0060] ② Negative voltage self-triggering mechanism: Utilizing V during a short circuit GS The negative voltage characteristic enables "zero detection delay shutdown", eliminating the need for an additional comparator circuit;

[0061] ③ Adaptive voltage compatibility: Supports direct communication between 3.3V / 5V MCU voltage and 7.4V–12.6V lithium battery voltage, eliminating the need for a dedicated level conversion chip;

[0062] ④ Low cost and no additional power consumption: Simple MOS transistor circuit, few components, small space occupation, and the function is implemented at a very low cost; and the sleep state does not increase the power consumption.

[0063] According to the bicycle derailleur protection system of this application, by setting front derailleur protection circuits and rear derailleur protection circuits, the communication power supply and communication signal at the wire end can be isolated from the communication level of the main chip at the PCB board end. When a short circuit occurs in the power supply and signal of the wire, the board end can quickly react and isolate the short circuit fault at the wire end without affecting the communication signal at the board end, protecting the main chip from high voltage surges. Simultaneously, it can be easily integrated into the compact space of the derailleur without increasing power consumption and at low cost. This system can quickly cut off short-circuit voltage / current (microsecond-level response); adapt to power supply voltage fluctuations (compatible with 8.4V~12.6V power supply); isolate the power supply voltage from the communication level of the chip's I / O port (TTL level 3.3V / 5V); be miniaturized, integrated, and reduce the number of components (adapting to the space constraints of bicycle derailleurs); and does not increase the overall power consumption, while being low in cost, offering a cost-performance advantage.

[0064] Secondly, embodiments of this application also propose a method for protecting bicycle derailleurs, such as... Figure 2 As shown, the method includes, but is not limited to, steps S100-S300:

[0065] Step S100: When the current derailleur communicates with the rear derailleur, a first signal is sent to the rear derailleur protection circuit through the first communication serial port of the first main control chip MCU1; the rear derailleur protection circuit performs level conversion on the first signal and sends the level-converted first signal to the front derailleur protection circuit through the power communication cable; the front derailleur protection circuit performs secondary level conversion on the level-converted first signal and sends the secondary level-converted first signal to the second communication serial port of the second main control chip MCU2;

[0066] Step S200: Alternatively, send a second signal to the front derailleur protection circuit through the second communication serial port of the second main control chip MCU2; perform level conversion on the second signal through the front derailleur protection circuit, and send the level-converted second signal to the rear derailleur protection circuit through the power communication cable; perform a second level conversion on the level-converted second signal through the rear derailleur protection circuit, and send the second level-converted second signal to the first communication serial port of the first main control chip MCU1;

[0067] Step S300: When the power line and communication line of the power communication cable are short-circuited, the first communication serial port is isolated from the power communication cable through the rear derailleur protection circuit, and the second communication serial port is isolated from the power communication cable through the front derailleur protection circuit.

[0068] Specifically, when the rear derailleur communicates with the front derailleur, when the first main control chip MCU1 of the rear derailleur sends a high-level first signal, the source voltage of the first MOSFET Q2 is pulled up to the system power supply VCC1 (3.3V or 5V) by the first pull-up resistor R1, and then the gate-source voltage V of the first MOSFET Q2... GS =0V, the first MOSFET Q2 is cut off, and the communication line is pulled up to VBAT (7.4V~12.6V) by the second pull-up resistor R2. A high-level first signal (7.4V~12.6V) is transmitted on the communication line. At this time, the receiver of the front derailleur receives the high-level first signal (7.4V~12.6V), which is higher than the source voltage of the fourth MOSFET Q3 (3.3V or 5V). Since the gate and source of the fourth MOSFET Q3 are pulled up to VCC2 (3.3V or 5V) by the sixth pull-up resistor R8, V... GS =0V, the fourth MOSFET Q3 is cut off, and the high-level signal on the communication line cannot pass through the fourth MOSFET Q3. Therefore, the RXD port of the second main control chip MCU2 detects a high level signal (3.3V or 5V). So the signal received by the front derailleur is high level (3.3V or 5V).

[0069] When the first main control chip MCU1 of the rear derailleur sends a low-level first signal, a voltage difference is generated between the gate and source of the first MOSFET Q2, V GS ≈3.3V or 5V > V th (Cutoff voltage), the first MOSFET Q2 is turned on, and the voltage on the communication line is pulled low by the low-level signal, transmitting a low-level signal (0~0.3V) on the communication line. At this time, the receiver of the front derailleur receives the first low-level signal (0~0.3V), because V GS =0V, the fourth MOSFET Q3 was originally cut off; however, due to the presence of the parasitic diode (source to drain) of the fourth MOSFET Q3, the low-side voltage is clamped to 0.7V (diode voltage drop); at this time V GS ≈3.3V - 0.7V = 2.6V > V th (Or: VGS≈5V-0.7V=4.3V>Vth), the fourth MOSFET Q3 is fully turned on, further pulling the low-voltage side down to near 0V. Therefore, the RXD port of the second main control chip MCU2 detects a low level signal (0~0.3V), so the signal received by the front derailleur is low level.

[0070] When the second main control chip MCU2 of the current derailleur sends a high-level second signal, the source voltage of the third MOSFET Q1 is pulled up to the system power supply VCC2 (3.3V or 5V) by the fourth pull-up resistor R4. Therefore, the gate-source voltage V of the third MOSFET Q1... GS =0V, the third MOSFET Q1 is cut off, and the communication line is pulled up to VBAT (7.4V~12.6V) by the fifth pull-up resistor R3, transmitting a high-level signal (7.4V~12.6V) on the communication line. At this time, the receiver of the rear derailleur receives a high-level second signal (7.4V~12.6V), which is higher than the source voltage of the second MOSFET Q4 (3.3V or 5V). Since the gate and source of the second MOSFET Q4 are pulled up to VCC1 (3.3V or 5V) by the third pull-up resistor R7, V GS =0V, the second MOSFET Q4 is cut off, and the high-level signal on the communication line cannot pass through the second MOSFET Q4. Therefore, the RXD port of the first main control chip MCU1 detects a high-level signal (3.3V or 5V). So the signal received by the rear derailleur is high-level (3.3V or 5V).

[0071] When the second main control chip MCU2 of the current derailleur sends a low-level second signal, a voltage difference is generated between the gate and source of the third MOSFET Q1, V GS ≈3.3V or 5V > V th (Cutoff voltage), the third MOSFET Q1 is turned on, and the voltage on the communication line is pulled low by the low-level signal, transmitting a low-level signal (0~0.3V) on the communication line. At this time, the receiver of the rear derailleur receives a low-level second signal (0~0.3V), because V GS =0V, the second MOSFET Q4 was originally cut off; however, due to the presence of the parasitic diode (source to drain) of the second MOSFET Q4, the low-side voltage is clamped to 0.7V (diode voltage drop); at this time V GS ≈3.3V - 0.7V = 2.6V > V th (Or: VGS≈5V-0.7V=4.3V>Vth), the second MOSFET Q4 is fully turned on, further pulling the low-voltage side down to near 0V. Therefore, the RXD port of the second main control chip MCU2 detects a low level signal (0~0.3V), so the signal received by the rear derailleur is low.

[0072] When a short circuit occurs between the communication line and the power line, the source voltage of the first MOSFET Q2 surges to VBAT (7.4V~12.6V), and the gate-source voltage V... GS= VCC1 - VBAT (e.g., 3.3V - 12.6V = -9.3V), far below the threshold voltage (Vth ≥ -0.7V), the first MOSFET Q2 is instantly turned off, physically isolating the high-voltage path; similarly, the source voltage of the third MOSFET Q1 rises sharply to VBAT (7.4V~12.6V), and the gate-source voltage V... GS = VCC2 - VBAT (e.g., 3.3V - 12.6V = -9.3V), far below the threshold voltage (Vth ≥ -0.7V), the third MOSFET Q1 is instantly turned off, physically isolating the high-voltage path. Furthermore, coordinated protection is provided by the first current-limiting resistor R5, the second current-limiting resistor R9, the third current-limiting resistor R6, and the fourth current-limiting resistor R10. The short-circuit current is limited to ≤30mA by 5 / R10 (typically 100Ω), preventing MOSFET breakdown. Utilizing V during a short circuit... GS The negative pressure characteristic achieves "zero detection delay shutdown," eliminating the need for an additional comparator circuit. The short-circuit protection principle for the front and rear derailleurs is as follows: Figure 3 As shown.

[0073] According to the bicycle derailleur protection method of this application, by setting a front derailleur protection circuit and a rear derailleur protection circuit, the communication power supply and communication signal at the wire end can be isolated from the communication level of the first main control chip MCU1 and the second main control chip MCU2 on the PCB board. When a short circuit occurs in the power supply and signal in the wire, the board can react quickly and isolate the short circuit fault at the wire end without affecting the communication signal on the board, protecting the first main control chip MCU1 and the second main control chip MCU2 from large voltage surges. This method can quickly cut off short-circuit voltage / current (microsecond-level response); adapt to power supply voltage fluctuations (compatible with 8.4V~12.6V power supply); isolate the power supply voltage from the communication level of the chip IO port (TTL level 3.3V / 5V); be miniaturized, integrated, and reduce the number of components (adapting to the space constraints of bicycle derailleurs); do not increase the overall power consumption, and have low cost, thus having a cost-performance advantage.

[0074] Thirdly, embodiments of the present invention also provide a storage medium, which is a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described bicycle gearbox protection method.

[0075] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof. The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate, and may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0076] Although specific embodiments are described herein, those skilled in the art will recognize that many other modifications or alternative embodiments are also within the scope of this disclosure. For example, any of the functions and / or processing capabilities described in connection with a particular device or component can be performed by any other device or component. Furthermore, while various exemplary embodiments and architectures have been described according to embodiments of this disclosure, those skilled in the art will recognize that many other modifications to the exemplary embodiments and architectures described herein are also within the scope of this disclosure.

[0077] The foregoing description, with reference to block diagrams and flowcharts of systems, methods, systems, and / or computer program products according to exemplary embodiments, has described certain aspects of this disclosure. It should be understood that one or more blocks in the block diagrams and flowcharts, as well as combinations of blocks in the block diagrams and flowcharts, can be implemented by executing computer-executable program instructions, respectively. Similarly, according to some embodiments, some blocks in the block diagrams and flowcharts may not need to be executed in the order shown, or may not all need to be executed. Furthermore, additional components and / or operations beyond those shown in the blocks in the block diagrams and flowcharts may exist in some embodiments.

[0078] Therefore, blocks in block diagrams and flowcharts support combinations of means for performing a specified function, combinations of elements or steps for performing a specified function, and program instruction means for performing a specified function. It should also be understood that each block in a block diagram and flowchart, and combinations of blocks in block diagrams and flowcharts, can be implemented by a dedicated hardware computer system or a combination of dedicated hardware and computer instructions that performs a specific function, element, or step.

[0079] The program modules, applications, etc., described herein may include one or more software components, including, for example, software objects, methods, data structures, etc. Each such software component may include computer-executable instructions that, in response to execution, cause at least a portion of the functionality described herein (e.g., one or more operations of the exemplary methods described herein) to be performed.

[0080] Software components can be coded using any of a variety of programming languages. An exemplary programming language could be a low-level programming language, such as assembly language associated with a specific hardware architecture and / or operating system platform. Software components including assembly language instructions may need to be converted into executable machine code by an assembler before being executed by the hardware architecture and / or platform. Another exemplary programming language could be a higher-level programming language that is portable across multiple architectures. Software components including higher-level programming languages ​​may need to be converted into an intermediate representation by an interpreter or compiler before execution. Other examples of programming languages ​​include, but are not limited to, macro languages, shell or command languages, job control languages, scripting languages, database query or search languages, or report writing languages. In one or more exemplary embodiments, a software component containing instructions from one of the above-described programming language examples can be executed directly by the operating system or other software components without first being converted into another form.

[0081] Software components can be stored as files or other data storage structures. Software components of similar type or related function can be stored together in a specific directory, folder, or library. Software components can be static (e.g., pre-defined or fixed) or dynamic (e.g., created or modified at runtime).

[0082] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A bicycle derailleur protection system, characterized in that, include: The rear derailleur has a first main control chip and a rear derailleur protection circuit, and the first main control chip has a first communication serial port. The front derailleur has a second main control chip and a front derailleur protection circuit, and the second main control chip has a second communication serial port. A power communication cable is provided, one end of which is electrically connected to the first communication serial port through the rear derailleur protection circuit, and the other end of which is electrically connected to the second communication serial port through the front derailleur protection circuit. The power communication cable has a communication line and a power line. The power line is used to provide power voltage to the rear derailleur and the front derailleur, and the communication line is used to enable communication between the rear derailleur and the front derailleur. When the rear derailleur and the front derailleur are communicating normally, the rear derailleur protection circuit is used to perform level conversion on the signals received or sent by the rear derailleur, and the front derailleur protection circuit is used to perform level conversion on the signals received or sent by the front derailleur. When the power line and the communication line are short-circuited, the rear derailleur protection circuit isolates the first communication serial port from the power communication cable, and the front derailleur protection circuit isolates the second communication serial port from the power communication cable. The first communication serial port includes a first transmitting serial port and a first receiving serial port; the second communication serial port includes a second transmitting serial port and a second receiving serial port; the rear derailleur protection circuit includes a first protection circuit and a second protection circuit; the first transmitting serial port is electrically connected to the first protection circuit; the first receiving serial port is electrically connected to the second protection circuit; the front derailleur protection circuit includes a third protection circuit and a fourth protection circuit; the second transmitting serial port is electrically connected to the third protection circuit; and the second receiving serial port is electrically connected to the fourth protection circuit. The first protection circuit includes a first MOSFET. The source of the first MOSFET is electrically connected to the first transmitting serial port. The source of the first MOSFET is also connected to the system power supply of the rear derailleur through a first pull-up resistor. The gate of the first MOSFET is electrically connected to the system power supply of the rear derailleur. The drain of the first MOSFET is connected to the power supply voltage through a second pull-up resistor. The drain of the first MOSFET is also electrically connected to one end of the power communication cable. A first parasitic diode is provided between the source and drain of the first MOSFET.

2. The bicycle derailleur protection system according to claim 1, characterized in that, The first protection circuit further includes a first current-limiting resistor, which is disposed between the first transmitting serial port and the source of the first MOS transistor.

3. The bicycle derailleur protection system according to claim 1, characterized in that, The second protection circuit includes a second MOSFET. The source of the second MOSFET is electrically connected to the first receiving serial port. The source of the second MOSFET is also connected to the system power supply of the rear derailleur through a third pull-up resistor. The gate of the second MOSFET is electrically connected to the system power supply of the rear derailleur. The drain of the second MOSFET is electrically connected to one end of the power communication cable. A second parasitic diode is provided between the source and drain of the second MOSFET.

4. The bicycle derailleur protection system according to claim 3, characterized in that, The second protection circuit also includes a second current-limiting resistor, which is disposed between the first receiving serial port and the source of the second MOS transistor.

5. The bicycle derailleur protection system according to claim 1, characterized in that, The third protection circuit includes a third MOSFET. The source of the third MOSFET is electrically connected to the second transmitting serial port. The source of the third MOSFET is also connected to the system power supply of the front derailleur through a fourth pull-up resistor. The gate of the third MOSFET is electrically connected to the system power supply of the front derailleur. The drain of the third MOSFET is connected to the power supply voltage through a fifth pull-up resistor. The drain of the third MOSFET is also electrically connected to the other end of the power communication cable. A third parasitic diode is located between the source and drain of the third MOSFET.

6. The bicycle derailleur protection system according to claim 5, characterized in that, The fourth protection circuit includes a fourth MOS transistor. The source of the fourth MOS transistor is electrically connected to the second receiving serial port. The source of the fourth MOS transistor is also connected to the system power supply of the front derailleur through a sixth pull-up resistor. The gate of the fourth MOS transistor is electrically connected to the system power supply of the front derailleur. The drain of the fourth MOS transistor is electrically connected to the other end of the power communication cable. A fourth parasitic diode is located between the source and drain of the fourth MOS transistor.

7. The bicycle derailleur protection system according to claim 6, characterized in that, The third protection circuit further includes a third current-limiting resistor, which is disposed between the second transmitting serial port and the source of the third MOS transistor. The fourth protection circuit further includes a fourth current-limiting resistor, which is disposed between the second receiving serial port and the source of the fourth MOS transistor.

8. A method for protecting a bicycle derailleur, characterized in that, Applied to the bicycle derailleur protection system as described in any one of claims 1-7, the method comprises: When the front derailleur communicates with the rear derailleur, a first signal is sent to the rear derailleur protection circuit through the first communication serial port of the first main control chip; the rear derailleur protection circuit performs level conversion on the first signal and sends the level-converted first signal to the front derailleur protection circuit through the power communication cable; the front derailleur protection circuit performs secondary level conversion on the level-converted first signal and sends the secondary level-converted first signal to the second communication serial port of the second main control chip; Alternatively, a second signal may be sent to the front derailleur protection circuit via the second communication serial port of the second main control chip; the front derailleur protection circuit may perform level conversion on the second signal and send the level-converted second signal to the rear derailleur protection circuit via the power communication cable; the rear derailleur protection circuit may perform secondary level conversion on the level-converted second signal and send the secondary level-converted second signal to the first communication serial port of the first main control chip; When the power line and communication line of the power communication cable are short-circuited, the first communication serial port is isolated from the power communication cable by the rear derailleur protection circuit, and the second communication serial port is isolated from the power communication cable by the front derailleur protection circuit.

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