A dual-axis voltage type tilt sensor with high protection performance

Abstract

The utility model relates to a double -axis voltage type angle of inclination sensor with high protection performance, including PCB circuit board, be equipped with on the PCB circuit board: LDO power supply circuit: through power end protection circuit and external input voltage connection, accelerometer circuit: to detect current three -axis acceleration, and send to MCU circuit, MCU circuit: including the MCU chip of accelerometer circuit connection, to realize the filter of acceleration data, temperature compensation and solution processing, and will double -axis angle output voltage data send to operational amplifier voltage amplification circuit, operational amplifier voltage amplification circuit: to double -axis angle output voltage data that MCU circuit sent is amplified, exports through voltage output end protection circuit. Compared with prior art, the utility model has the advantages of possessing reverse connection, short circuit, wrong connection protection capability and input, output overvoltage, overcurrent protection function, conforms to PL=d functional safety authentication and so on.

Description

Technical Field

[0001] This utility model relates to the field of tilt sensors, and in particular to a biaxial voltage-type tilt sensor with high protection performance. Background Technology

[0002] A tilt sensor is a device used to measure the angle of inclination of an object relative to a horizontal plane. It determines the tilt angle by detecting the component of gravitational acceleration along the sensor axis and is widely used in construction, automotive, aerospace, and industrial equipment to monitor and control tilt conditions.

[0003] High-protection dual-axis voltage-type tilt sensors typically use MEMS accelerometers to detect static tilt angles. The tilt angle value is calculated by performing an arcsine function on the gravitational acceleration component along one axis of the accelerometer, and then converted into a voltage signal output of 0.5V to 4.5V. Typically, in a horizontal state, both axes output voltages are 2.5V. Common voltage signals are converted from digital signals to voltage signals using a DAC chip. However, ordinary DAC chips have weak voltage withstand and fault-tolerant capabilities. Furthermore, since the output signal is a voltage signal, it's impossible to prevent high voltage input or incorrect power supply connection by connecting a diode in series in the voltage output circuit (because diodes have a significant voltage drop that affects output voltage accuracy). To prevent direct damage to the sensor from incorrect power supply connection to the voltage output terminal, a miniature relay is usually used within the sensor to prevent incorrect wiring (when the power supply is incorrectly connected, the voltage output circuit is closed through the normally open contact of the relay, preventing the supply voltage from being introduced to the DAC voltage output terminal, thus avoiding damage to the DAC). However, this method is only effective for incorrect wiring. If the power cord is connected correctly, short-circuiting the voltage output to the positive or negative terminal of the power supply may still cause the DAC chip to burn out or suffer internal damage.

[0004] In summary, voltage-type tilt sensors often have weak protection at the voltage output end, and are generally open-loop outputs without verification or diagnosis of the correctness of the output voltage, resulting in low reliability. Currently, there are many similar dual-axis voltage output tilt sensors on the market, but they lack or cannot simultaneously possess high-level EMC protection, PL=d functional safety compliance design, and comprehensive reverse connection, short circuit, and incorrect connection protection.

[0005] Furthermore, due to the low supply voltage of 5V, EMC protection circuitry is difficult to design due to limitations in the space of the tilt sensor housing and PCB area. Typically, 5V power supply circuits lack surge and EFT interference protection. Utility Model Content

[0006] To address the technical problems in the background art, this utility model provides a biaxial voltage-type tilt sensor with high protection performance, including a housing and a PCB circuit board disposed within the housing, wherein the PCB circuit board is provided with:

[0007] LDO power supply circuit: It is connected to the external input voltage through the power supply protection circuit to realize voltage conversion and power supply to the accelerometer circuit and MCU circuit, and to power the operational amplifier voltage amplification circuit through the DC-DC power supply circuit.

[0008] Accelerometer circuit: used to detect the current triaxial acceleration and send it to the MCU circuit;

[0009] MCU circuit: Includes an MCU chip connected to the accelerometer circuit, used to filter, temperature compensate and solve the acceleration data, and send the dual-axis angle output voltage data to the operational amplifier voltage amplification circuit;

[0010] Operational amplifier voltage amplifier circuit: used to amplify the dual-axis angle output voltage data sent by the MCU circuit, and then output it after passing through the voltage output protection circuit.

[0011] Furthermore, the LDO power supply circuit includes an LDO chip to convert the +5V external input voltage to a +3.3V voltage, and a Zener diode is set at the output terminal of the LDO chip to limit the output voltage of the LDO chip under interference or fault conditions.

[0012] Furthermore, the DC-DC power supply circuit includes a DC-DC chip to boost the +3.3V voltage to above +4.5V. A transient voltage suppression diode is set at the output terminal of the DC-DC chip to limit the output voltage of the DC-DC chip under interference or fault conditions. A diode is also set to prevent external voltage backflow.

[0013] Furthermore, the power supply protection circuit includes a differential mode surge voltage absorption circuit, a common mode surge voltage absorption circuit, and a transient protection diode circuit connected in parallel between the +5V external input voltage and ground. The differential mode surge voltage absorption circuit includes a first varistor and a gas discharge tube connected in series. The common mode surge voltage absorption circuit includes a second varistor and a third varistor connected in series. The transient protection diode circuit is equipped with a transient protection diode.

[0014] Furthermore, the power supply protection circuit also includes a resettable fuse and a diode. The resettable fuse and the diode are connected in series between the +5V external input voltage and the output terminal of the power supply protection circuit. One end of the transient protection diode is connected between the resettable fuse and the diode, and the other end is grounded.

[0015] Furthermore, the operational amplifier voltage amplification circuit consists of a first operational amplifier sub-circuit and a second operational amplifier sub-circuit with identical structures. The first operational amplifier sub-circuit and the second operational amplifier sub-circuit are respectively connected to the two DACs of the MCU chip, and the voltage output terminal is protected against overvoltage, overcurrent, negative voltage and voltage reverse flow through Schottky diodes, unidirectional transient voltage suppression diodes and self-resetting fuses.

[0016] Furthermore, it also includes a voltage signal acquisition circuit, used to realize the voltage acquisition and monitoring of the LDO power supply circuit, DC-DC power supply circuit and operational amplifier voltage amplification circuit by the MCU chip, specifically:

[0017] For LDO power supply circuits: The MCU chip acquires and monitors the output voltage of the LDO power supply circuit through its own power supply voltage detection;

[0018] For DC-DC power supply circuits: the MCU chip acquires and monitors the output voltage of the DC-DC power supply circuit through a voltage divider using resistors connected in series.

[0019] For op-amp voltage amplification circuits: the MCU chip acquires and monitors the dual-axis angle output voltage signals of the first op-amp sub-circuit and the second op-amp sub-circuit through voltage division by resistors connected in series.

[0020] Furthermore, in the voltage signal acquisition circuit, the resistors connected in series with each other in the operational amplifier voltage amplifier circuit acquire and monitor the dual-axis angle output voltage signals of the operational amplifier circuit, and their resistance values ​​are the same.

[0021] Furthermore, it also includes auxiliary circuits, which include a temperature compensation indicator sub-circuit, a debug serial port protection sub-circuit, and an SWD programming interface current limiting sub-circuit, all of which are connected to the MCU chip.

[0022] Furthermore, after completing filtering, temperature compensation, calculation processing, and angle calibration and adjustment, a self-diagnostic process is performed, which specifically includes the following steps:

[0023] 1) Check if the MCU power-on self-test is normal. If yes, proceed to step 2); if no, proceed to step 7.

[0024] 2) Determine if the LDO output voltage is within the normal range. If yes, proceed to step 3); otherwise, proceed to step 7.

[0025] 3) Determine if the DC-DC output voltage is within the normal range. If yes, proceed to step 4); otherwise, proceed to step 7.

[0026] 4) Determine if the communication with the accelerometer is normal. If yes, proceed to step 5); otherwise, proceed to step 7.

[0027] 5) Determine if the op-amp voltage output is normal. If yes, proceed to step 6); otherwise, proceed to step 7.

[0028] 6) Normal output voltage signal;

[0029] 7) Enter safe mode and turn off voltage signal output.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] This utility model provides a dual-axis voltage-type tilt sensor with high protection performance. By designing a power supply protection circuit, the power input terminal can withstand differential mode ±500V and common mode ±1kV surge voltage interference, while the power supply terminal can withstand ±1kV (5kHz or 100kHz) pulse group interference. Through the transient protection diode in the circuit to absorb static electricity, it can withstand ±8kV contact discharge and ±15kV air discharge interference. In addition, it also has reverse connection, short circuit, and incorrect connection protection capabilities, as well as input and output overvoltage and overcurrent protection functions. Attached Figure Description

[0032] Figure 1 A schematic diagram of a dual-axis voltage-type tilt sensor with high protection performance provided by this utility model;

[0033] Figure 2 This is a schematic diagram of the circuit structure for the power supply protection circuit.

[0034] Figure 3 This is a schematic diagram of the circuit structure of an LDO power supply circuit.

[0035] Figure 4 This is a schematic diagram of the circuit structure of a DC-DC power supply circuit.

[0036] Figure 5 This is a schematic diagram of the accelerometer circuit.

[0037] Figure 6 Figure 6a shows the circuit structure of the MCU and its peripheral circuits, and Figure 6b shows the circuit structure of the peripheral circuits.

[0038] Figure 7 Figure 7a shows the circuit structure of the operational amplifier voltage amplifier circuit, and Figure 7b shows the circuit structure of the first operational amplifier sub-circuit.

[0039] Figure 8Figure 8a is a schematic diagram of the circuit structure of the temperature compensation indicator light sub-circuit, Figure 8b is a schematic diagram of the circuit structure of the debugging serial port protection sub-circuit, and Figure 8c is a schematic diagram of the circuit structure of the SWD programming interface current limiting sub-circuit.

[0040] Figure 9 This is a voltage signal acquisition circuit;

[0041] Figure 10 This is the main flowchart of the product's program.

[0042] Figure 11 This is a flowchart of angle calculation and calibration. Detailed Implementation

[0043] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. This embodiment is based on the technical solution of the present invention and provides detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0044] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the utility model product is usually placed in during use. They are only for the convenience of describing the utility model 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 limitations on the utility model.

[0046] The terms “first” and “second” are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0047] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0048] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0049] Example

[0050] like Figure 1 As shown, this utility model provides a dual-axis voltage-type tilt sensor with high protection performance. The tilt sensor uses a 5V power supply and a 0.5V~4.5V voltage output, and has high protection performance and meets the safety level of PL=d. It includes a housing, a connector, and a PCB circuit board disposed in the housing. The PCB circuit board includes a power supply protection circuit, an LDO power supply circuit, a DC-DC power supply circuit, an accelerometer circuit, an MCU circuit, an operational amplifier voltage amplification circuit, a voltage signal acquisition circuit, an auxiliary circuit, and a voltage output protection circuit. The input terminal of the power supply protection circuit is connected to an external +5V power supply input, and the output terminal is connected to the LDO power supply circuit. The output terminal of the LDO power supply circuit is connected to the DC-DC power supply circuit, the accelerometer circuit, and the MCU circuit for power supply. The output terminal of the DC-DC power supply circuit is connected to the operational amplifier voltage amplification circuit for power supply. The MCU circuit is connected to the output voltage signal acquisition circuit, the auxiliary circuit, and the operational amplifier voltage amplification circuit for power supply. The operational amplifier voltage amplification circuit outputs an angle voltage signal through the voltage output protection circuit.

[0051] like Figure 2 As shown, the power supply protection circuit includes terminal J1, varistor M1, varistor M2, varistor M3, gas discharge tube G1, resettable fuse F1, transient protection diode D2, and diode D3. It mainly absorbs surge interference and pulse group interference through surge protection design, and together with the layout and wiring of the PCB circuit board, it achieves the ability to withstand ±1kV (5kHz or 100kHz) pulse group interference.

[0052] Varistor M1 and gas discharge tube G1 are connected in series between VCC and GND at terminal J1 to absorb differential mode surge voltage (±500V). Varistor M2 and varistor M3 are connected in series between VCC and GND at terminal J1 to absorb common mode surge voltage (±1kV). A grounding terminal EGND is provided between varistor M2 and varistor M3. Resettable fuse F1 and diode D3 are located between VCC at terminal J1 and output terminal SUP. One end of transient protection diode D2 is connected between resettable fuse F1 and diode D3, and the other end is grounded. Resettable fuse F1 and transient protection diode D2 are used to absorb residual differential mode surge voltage, as well as overvoltage and overcurrent protection of power supply input, and to withstand ±8kV contact discharge and ±15kV air discharge interference. Diode D3 is used for reverse connection protection.

[0053] like Figure 3As shown, the LDO power supply circuit includes an LDO chip U1, whose pin 1 VIN is connected to the output terminal SUP of the power supply protection circuit to convert the +5V input voltage to a +3.3V voltage, which is output from pin 5 OUT to power the components of the back-end circuit. Capacitors C14, C4, and C5 are input filtering and decoupling capacitors, and capacitors C6 and C7 are output filtering and decoupling capacitors. One end of the Zener diode D1 is grounded, and the other end is connected to pin 5 OUT of the LDO chip U1 to limit the output voltage of the LDO chip U1 under interference or abnormal fault conditions, so as to avoid burning out the components of the back-end circuit.

[0054] like Figure 4 As shown, the DC-DC power supply circuit is used to boost the +3.3V voltage to +7V to power the operational amplifier voltage amplification circuit. It includes a DC-DC chip U9, an inductor L2, a transient voltage suppression diode D10, a diode D9, and a diode D14.

[0055] The normal supply voltage of the LDO power supply circuit is +5V. Since the protection circuit at the power supply end has a protection diode that will generate a voltage drop, if you want to output a voltage signal of up to 4.5V, you must increase the supply voltage of the op-amp voltage amplifier circuit to above 4.5V.

[0056] Capacitor C44 is connected between pin 5 (IN) of DC-DC chip U9 and ground for input filtering. Resistor R34 is placed between pin 4 of DC-DC chip U9 and ground to ensure the DC-DC chip is in a default output-off state. Inductor L2, diode D9, and DC-DC chip U9 form a BOOST boost circuit. Resistors R33 and R35 form a DC-DC output voltage feedback network. Pin 3 of DC-DC chip U9 is connected between resistors R33 and R35. Transient voltage suppression diode D10 is used to limit the output voltage of DC-DC chip under interference or fault conditions to prevent damage to downstream circuit components. Diode D14 is used to prevent external voltage from flowing back into DC-DC chip U9.

[0057] like Figure 5 As shown, the accelerometer circuit includes an accelerometer chip U2 and power supply filtering and decoupling capacitors C1, C2, and C3. The accelerometer chip U2 is supplied with a +3.3V voltage by an LDO power supply circuit and communicates with the MCU circuit. In this example, the accelerometer is specifically a triaxial accelerometer.

[0058] like Figure 6As shown, the MCU circuit includes the MCU chip U11 and its peripheral circuits. Resistor R39 and capacitors C47 and C48 form the reference voltage filtering and decoupling circuit of the MCU chip U11. Resistor R37 and capacitor C42 form the reset circuit of the MCU chip U11. Resistor R9 provides a low-level signal to the BOOT0 pin of the MCU chip U11. Capacitors C11, C12, C13, and C40 are power supply filtering and decoupling capacitors for the MCU chip U11. Resistor R10 is the short-circuit resistor between the digital ground and analog ground of the MCU chip U11. Transient voltage suppression diode D13 is used to protect the MCU circuit.

[0059] Specifically, pin 1 (LED_R) of MCU chip U11 is connected to the temperature compensation indicator sub-circuit to indicate the temperature compensation status; the power input pin is connected to the output of the LDO power circuit; the first set of SPI pins (pins 42-45) is connected to the accelerometer chip U2, and the second set of SPI pins (pins 25-28) is reserved as expandable pins; the two DAC output pins (pins 15 and 16) are connected to the first and second operational amplifier sub-circuits respectively; the DC-DC power supply circuit voltage sampling pin (pin 20) is connected to the DC-DC power supply circuit; the operational amplifier voltage amplification circuit voltage sampling pins (pins 13 and 18) are connected to the operational amplifier voltage amplification circuit through the voltage acquisition sub-circuit in the voltage signal acquisition circuit respectively; the SWD programming pins (pins 35 and 36) are connected to the SWD programming interface current limiting sub-circuit; and the debug serial port pins (pins 29 and 32) are connected to the debug serial port protection sub-circuit.

[0060] like Figure 7 As shown in 7a and 7b, the operational amplifier voltage amplification circuit consists of a first operational amplifier sub-circuit and a second operational amplifier sub-circuit. This circuit includes a first operational amplifier chip U5 and a second operational amplifier chip U8, which are used to amplify the output voltages of the two internal DACs of the MCU chip U11. Resistors R7 and R8 are used to provide a stable ground level so that the output voltage is about 0V when the DAC has no output. Resistors R5 and R18 and capacitors C18, C21, C31 and C35 form an operational amplifier power supply filter circuit. Resistors R13, R14, R25 and R26 are used to adjust the amplification factor of the amplifier circuit.

[0061] In the voltage output protection circuit, Schottky diodes D5 and D7, unidirectional transient voltage suppression diodes D6 and D8, and resettable fuses F2 and F3 are used to protect the voltage output from overvoltage, overcurrent, negative voltage, and voltage reverse flow.

[0062] like Figure 8 As shown, the auxiliary circuit includes a temperature compensation indicator light sub-circuit (such as...). Figure 8 As shown in a), debug the serial port protection sub-circuit (such as...). Figure 8 (as shown in b) and the SWD programming interface current limiting sub-circuit (as shown in b) Figure 8 As shown in c), one end of the temperature compensation indicator subcircuit is grounded, and the other end is connected to the temperature compensation indicator pin of the MCU chip U11. This subcircuit consists of resistor R5 and LED D4 connected in series. The debug serial port protection subcircuit is connected to the MCU chip U11. This subcircuit consists of resistors R17 and R23, Zener diodes D11 and D12, and debug port J7. The SWD programming interface current limiting subcircuit is connected to the MCU chip U11. This subcircuit consists of resistors R24 and R36, and SWD programming port J8.

[0063] The voltage signal acquisition circuit is used to acquire voltage signals from the LDO power supply circuit, DC-DC power supply circuit, and operational amplifier voltage amplification circuit, and then send the acquired voltage signals to the MCU chip U11.

[0064] For the LDO power supply circuit, the MCU chip U11 monitors the output voltage of the LDO power supply circuit by detecting its own supply voltage.

[0065] For DC-DC power supply circuits, by Figure 4 As shown, resistors R11 and R12 are connected in series to divide the DC-DC output voltage for monitoring. The voltage signal N_7V*0.253731 is connected to pin 20 of the MCU chip U11.

[0066] For op-amp voltage amplifier circuits, such as Figure 9 As shown, resistors R1 and R2 are connected in series with equal resistance. One end is connected to analog ground AGND, and the other end is connected to the voltage output Vx of the first operational amplifier chip U5 in the first operational amplifier sub-circuit. Pin 13 of the MCU chip U11 is connected between resistors R1 and R2 to divide and acquire the voltage signal Vx_HALF. Similarly, resistors R3 and R4 are connected in series with equal resistance. One end is connected to analog ground AGND, and the other end is connected to the voltage output Vy of the second operational amplifier chip U8 in the first operational amplifier sub-circuit. Pin 18 of the MCU chip U11 is connected between resistors R3 and R4 to divide and acquire the voltage signal Vy_HALF.

[0067] Based on the above, the present invention provides a dual-axis voltage-type tilt sensor with high protection performance. Its high protection capability is mainly achieved by circuit design, and its functional safety is mainly achieved by hardware design and software diagnosis. The flowchart only provides the main loop process and software diagnosis process for implementing the tilt sensor.

[0068] like Figure 10 As shown, the main loop of the operating program for a dual-axis voltage-type tilt sensor with high protection performance according to this utility model includes the following steps:

[0069] 1. Collect raw triaxial acceleration data from the triaxial accelerometer;

[0070] 2. Filter the raw acceleration data, using methods such as Kalman filtering;

[0071] 3. Perform temperature compensation on the filtered acceleration values;

[0072] 4. Calculate the angle of the acceleration value after temperature compensation;

[0073] 5. Angle calibration and adjustment;

[0074] 6. Various self-diagnoses.

[0075] like Figure 11 As shown, the specific steps involved in performing each self-diagnosis are as follows:

[0076] 61) Check if the MCU power-on self-test is normal. If yes, proceed to step 62); if no, proceed to step 67.

[0077] 62) Determine if the LDO output voltage is within the normal range. If yes, proceed to step 63); otherwise, proceed to step 67.

[0078] 63) Determine if the DC-DC output voltage is within the normal range. If yes, proceed to step 64); otherwise, proceed to step 67.

[0079] 64) Determine if the communication with the accelerometer is normal. If yes, proceed to step 65); otherwise, proceed to step 67.

[0080] 65) Determine if the op-amp voltage output is normal. If yes, proceed to step 66); otherwise, proceed to step 67.

[0081] 66) Normal output voltage signal;

[0082] 67) Enter safe mode and turn off voltage signal output.

[0083] In summary, this utility model provides a dual-axis voltage-type tilt sensor with high protection performance. The circuit design conforms to the functional safety certification requirements of PL=d. Through the design of the power supply protection circuit, the power input terminal can withstand differential mode ±500V and common mode ±1kV surge voltage interference, while also withstanding ±1kV (5kHz or 100kHz) pulse group interference. The transient protection diode in the circuit absorbs static electricity, enabling it to withstand ±8kV contact discharge and ±15kV air discharge interference. Furthermore, it also features reverse connection, short circuit, and incorrect connection protection capabilities, as well as input and output overvoltage and overcurrent protection functions.

[0084] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A biaxial voltage-type tilt sensor with high protection performance, comprising a housing and a PCB circuit board disposed within the housing, characterized in that, The PCB circuit board is equipped with: LDO power supply circuit: It is connected to the external input voltage through the power supply protection circuit to realize voltage conversion and power supply to the accelerometer circuit and MCU circuit, and to power the operational amplifier voltage amplification circuit through the DC-DC power supply circuit. Accelerometer circuit: used to detect the current triaxial acceleration and send it to the MCU circuit; MCU circuit: Includes an MCU chip connected to the accelerometer circuit, used to filter, temperature compensate and solve the acceleration data, and send the dual-axis angle output voltage data to the operational amplifier voltage amplification circuit; Operational amplifier voltage amplifier circuit: used to amplify the dual-axis angle output voltage data sent by the MCU circuit, and then output it after passing through the voltage output protection circuit.

2. A biaxial voltage-type tilt sensor with high protection performance according to claim 1, characterized in that, The LDO power supply circuit includes an LDO chip to convert the +5V external input voltage to a +3.3V voltage, and a Zener diode is set at the output of the LDO chip to limit the output voltage of the LDO chip under interference or fault conditions.

3. A biaxial voltage-type tilt sensor with high protection performance according to claim 1, characterized in that, The DC-DC power supply circuit includes a DC-DC chip to boost the +3.3V voltage to above +4.5V. A transient voltage suppression diode is set at the output terminal of the DC-DC chip to limit the output voltage of the DC-DC chip under interference or fault conditions. A diode is also set to prevent external voltage backflow.

4. A biaxial voltage-type tilt sensor with high protection performance according to claim 1, characterized in that, The power supply protection circuit includes a differential mode surge voltage absorption circuit, a common mode surge voltage absorption circuit, and a transient protection diode circuit connected in parallel between the +5V external input voltage and ground. The differential mode surge voltage absorption circuit includes a first varistor and a gas discharge tube connected in series. The common mode surge voltage absorption circuit includes a second varistor and a third varistor connected in series. The transient protection diode circuit is equipped with a transient protection diode.

5. A biaxial voltage-type tilt sensor with high protection performance according to claim 4, characterized in that, The power supply protection circuit also includes a resettable fuse and a diode. The resettable fuse and the diode are connected in series between the +5V external input voltage and the output of the power supply protection circuit. One end of the transient protection diode is connected between the resettable fuse and the diode, and the other end is grounded.

6. A biaxial voltage-type tilt sensor with high protection performance according to claim 1, characterized in that, The operational amplifier voltage amplification circuit consists of a first operational amplifier sub-circuit and a second operational amplifier sub-circuit with identical structures. The first operational amplifier sub-circuit and the second operational amplifier sub-circuit are respectively connected to the two DACs of the MCU chip, and the voltage output terminal is protected against overvoltage, overcurrent, negative voltage and voltage reverse flow through Schottky diodes, unidirectional transient voltage suppression diodes and self-resetting fuses.

7. A biaxial voltage-type tilt sensor with high protection performance according to claim 6, characterized in that, It also includes a voltage signal acquisition circuit, used to enable the MCU chip to acquire and monitor the voltages of the LDO power supply circuit, DC-DC power supply circuit, and operational amplifier voltage amplification circuit, specifically: For LDO power supply circuits: The MCU chip acquires and monitors the output voltage of the LDO power supply circuit through its own power supply voltage detection; For DC-DC power supply circuits: the MCU chip acquires and monitors the output voltage of the DC-DC power supply circuit through a voltage divider using resistors connected in series. For op-amp voltage amplification circuits: the MCU chip acquires and monitors the dual-axis angle output voltage signals of the first op-amp sub-circuit and the second op-amp sub-circuit through voltage division by resistors connected in series.

8. A biaxial voltage-type tilt sensor with high protection performance according to claim 7, characterized in that, In the voltage signal acquisition circuit, the resistors connected in series with each other have the same resistance value to acquire and monitor the dual-axis angle output voltage signal of the operational amplifier voltage amplifier circuit.

9. A biaxial voltage-type tilt sensor with high protection performance according to claim 1, characterized in that, It also includes auxiliary circuits, which include a temperature compensation indicator sub-circuit, a debug serial port protection sub-circuit, and an SWD programming interface current limiting sub-circuit, all of which are connected to the MCU chip.

Images