Conditioning circuit for IEPE acceleration sensor, vehicle-mounted controller and vehicle
By adjusting the voltage division and signal switching in the conditioning module, the matching problem between the IEPE sensor and the controller analog-to-digital converter is solved, stable signal conversion and improved accuracy are achieved, and circuit costs are reduced.
Patent Information
- Application Number
- CN202423015586.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2025-10-24
- Estimated Expiration
- 2034-12-06
AI Technical Summary
The sensitivity and output amplitude of different IEPE accelerometers vary greatly, making it difficult to match the acquisition range of the controller's analog-to-digital converter.
A constant current source and conditioning module are used, including a first voltage divider unit, a switching unit, a second voltage divider unit, a voltage follower module, a voltage limiting module and a filtering module. By adjusting the voltage divider ratio and signal switching, the sensitivity of different sensors is matched, and the analog switch and diode protection circuit are used to ensure that the signal is within the appropriate range.
The amplitude matching of different IEPE sensor signals and the adaptation of the controller's analog-to-digital converter are achieved, which improves signal accuracy and stability and reduces circuit cost.
Smart Images
Figure CN223471265U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a circuit technical field especially relates to a kind of conditioning circuit for IEPE acceleration sensor, vehicle controller and vehicle. BACKGROUND
[0002] Integral Electronic Piezoelectric (IEPE) sensor is a kind of acceleration sensor with charge amplifier, current is introduced into acceleration sensor by external current source, and the voltage of return signal is proportional to acceleration.
[0003] However, the sensitivity of different IEPE sensors on the market is different, and the output amplitude difference is large, which is difficult to match the acquisition range of the analog-digital converter of the controller.
[0004] In summary, it is necessary to provide a conditioning circuit for IEPE acceleration sensor, vehicle controller and vehicle that can match the acquisition range of the analog-digital converter of the controller for different IEPE acceleration sensors. SUMMARY
[0005] To solve the above problems, the utility model provides a conditioning circuit for IEPE acceleration sensor, vehicle controller and vehicle.
[0006] In the first aspect, the application provides a conditioning circuit for IEPE acceleration sensor, comprising: a constant current source and a conditioning module;
[0007] The constant current source is connected to the sensor and the conditioning module respectively;
[0008] The conditioning module includes a first voltage dividing unit, a switching unit and a second voltage dividing unit;
[0009] One end of the first voltage dividing unit is connected to the constant current source and the sensor, and the other end is connected to one end of the switching unit;
[0010] The other end of the switching unit is connected to any one of the multiple connection ends of the second voltage dividing unit.
[0011] Further, as the conditioning circuit described above, the second voltage dividing unit includes: a first resistor, a second resistor and a third resistor, one end of the first resistor, one end of the second resistor and one end of the third resistor are used to be connected to the other end of the switching unit.
[0012] Further, the conditioning circuit as described above further comprises: a voltage follower module; a first input terminal of the voltage follower module is connected with the other terminal of the first voltage dividing unit, and a second input terminal of the voltage follower module is connected with an output terminal.
[0013] Further, the conditioning circuit as described above further comprises: a voltage limiting module; the voltage limiting module is connected with the output terminal of the voltage follower module.
[0014] Further, the conditioning circuit as described above, the voltage limiting module comprises: a first diode and a second diode.
[0015] The negative electrode of the first diode is connected with a power supply terminal, the positive electrode is connected with the negative electrode of the second diode and the output terminal of the voltage follower module; the positive electrode of the second diode is connected with a ground terminal.
[0016] Further, the conditioning circuit as described above further comprises: a filter module; an input terminal of the filter module is connected with the voltage limiting module.
[0017] Further, the conditioning circuit as described above, the filter module comprises: a sixth-order Butterworth low-pass filter.
[0018] Further, the conditioning circuit as described above, the sixth-order Butterworth low-pass filter comprises three second-order Butterworth low-pass filters connected in parallel.
[0019] In a second aspect, the application provides a vehicle-mounted controller comprising the conditioning circuit for the IEPE acceleration sensor according to any one of the first aspect.
[0020] In a third aspect, the application provides a vehicle comprising the vehicle-mounted controller according to the second aspect.
[0021] The conditioning circuit for the IEPE acceleration sensor according to the first aspect has the following advantages: the switching unit in the conditioning module is connected with any one of the multiple connection terminals of the first voltage dividing unit and the second voltage dividing unit, the voltage dividing of the first voltage dividing unit and the second voltage dividing unit on the output signal of the sensor is adjusted, the amplitude of the output signal is adjusted, and the output signal of different sensors can match the acquisition range of the analog-to-digital converter of the controller. BRIEF DESCRIPTION OF DRAWINGS
[0022] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of preferred embodiments, and are not meant to limit the present application. Furthermore, the same reference numerals are intended to identify the same components throughout the various figures. In the drawings:
[0023] Figure 1is a schematic diagram of a conditioning circuit of an existing IEPE sensor;
[0024] Figure 2 is a schematic diagram of a conditioning circuit of an IEPE acceleration sensor provided by the utility model;
[0025] Figure 3 is a schematic diagram of another conditioning circuit of an IEPE acceleration sensor provided by the utility model. DETAILED DESCRIPTION
[0026] Further description will be made to the exemplary embodiments of the utility model in combination with the accompanying drawings. Although the exemplary embodiments of the utility model are shown in the drawings, it should be understood that the utility model can be realized in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the utility model and to convey the scope of the utility model to those skilled in the art.
[0027] The utility model embodiments will be described in detail below in combination with the accompanying drawings.
[0028] For the conditioning circuit of the IEPE acceleration sensor (IEPE sensor), the existing technical method mainly focuses on isolating the direct current component in the IEPE sensor input signal through the capacitor, and reducing the signal through the operational amplifier. As shown in Figure 1 is a conditioning circuit of an existing IEPE sensor, which comprises a piezoelectric acceleration sensor 1, a vibration detection circuit module 2 and a digital circuit module 3. The vibration detection circuit module 2 comprises a constant current source circuit 4, an input amplifier 5, a program-controlled amplifier 6, an output amplifier 7, an integrator 8, an analog switch 9, an anti-aliasing filter 10 and an ADC analog-to-digital converter 11 connected in sequence. As shown in Figure 1 , the conditioning circuit isolates the static direct current bias in the piezoelectric acceleration sensor 1 signal through the capacitor C12.
[0029] However, filtering the direct current component (direct current bias) in the original signal through the capacitor has certain requirements for the capacitance value and accuracy of the capacitor. The low capacitance capacitor will filter out the low frequency component of the effective signal while isolating the direct current, and the tolerance of the same type of capacitor on the market is large and the consistency is poor, which will cause certain differences in the signals collected by different hardware channels. Although a high-capacitance high-voltage capacitor can be used, this will increase the cost.
[0030] And the amplitude conditioning method through the operational amplifier has a fixed voltage division ratio, which is poor in matching for IEPE sensors with different sensitivities.
[0031] At present, different IEPE sensors on the market have different sensitivities and large output amplitude differences. At the same time, there is a high voltage bias, which is difficult to match the 0-5V acquisition range of the analog-to-digital converter ADC in the controller.
[0032] Therefore, in order to solve the technical problem of the mismatch between the acquisition range of the analog-to-digital converter ADC in the controller and the different sensitivities of different IEPE sensors on the market and the high voltage bias, the embodiment of the present application proposes a conditioning circuit for an IEPE acceleration sensor, a vehicle-mounted controller and a vehicle.
[0033] The first aspect, as shown in Figure 2 According to the embodiment of the present application, a conditioning circuit for an IEPE acceleration sensor is provided, which comprises a constant current source 100 and a conditioning module 200. The constant current source 100 is connected to the sensor and the conditioning module 200 respectively; the conditioning module 200 comprises a first voltage dividing unit 201, a switching unit 203 and a second voltage dividing unit 202; one end of the first voltage dividing unit 201 is connected to the constant current source 100 and the sensor S, and the other end is connected to one end of the switching unit 203; the other end of the switching unit 203 is connected to any one of the multiple connection ends of the second voltage dividing unit 202.
[0034] The input voltage of the constant current source 100 is 24V, and the output voltage is 12V. The switching unit 203 comprises an analog switch. The analog switch is mainly used to complete the signal switching function in the signal link. MOS tube and other switching modes can be used to realize the shutdown (disconnection) or conduction of the signal link; since its function is similar to that of a switch, it is realized by the characteristics of analog devices, and is called an analog switch. The sensor S comprises an IEPE acceleration sensor. The constant current source 100 inputs a 12V DC bias voltage.
[0035] Since the IEPE sensors on the market have different output sensitivities (such as 10mV / g, 100mV / g, 500mV / g, etc.), the output voltage amplitude of the same acceleration is quite different under different sensor sensitivities. By introducing the analog switch SW in the switching unit 203, the connection of the first voltage dividing unit 201 and the multiple connection ends of the second voltage dividing unit 202 can be changed, so that the input signal amplitude can be adjusted by selecting different IEPE sensor sensitivities through the program and selecting different voltage dividing ratios through the control signal to control the analog switch SW in the switching unit 203.
[0036] As shown in Figure 3 The second voltage dividing unit 202 comprises a first resistor R1, a second resistor R2 and a third resistor R3, one end of the first resistor R1, one end of the second resistor R2 and one end of the third resistor R3 are all connected to the other end of the switching unit 203.
[0037] The other ends of the first resistor R1, the second resistor R2 and the third resistor R3 are connected with a ground terminal.
[0038] As shown in Figure 3 The embodiment of the present application further includes a voltage follower module 300; a first input terminal (positive input terminal) of the voltage follower module 300 is connected with the other end of the first voltage dividing unit 201, and a second input terminal (negative input terminal) of the voltage follower module 300 is connected with the output terminal.
[0039] The voltage follower module 300 includes a voltage follower. The voltage follower is also called a unit gain amplifier, a buffer amplifier and an isolation amplifier, and is an operational amplifier circuit with a voltage gain of 1. The voltage follower does not amplify the voltage signal. Although the output signal of the voltage follower is basically equal to the input signal, the voltage follower improves the load capacity. Since the voltage follower has the characteristics of high input impedance and low output impedance, the voltage follower can reduce the interference of the post-circuit on the voltage dividing resistor and the interference of the pre-circuit on the anti-aliasing filter frequency, and improve the circuit precision.
[0040] As shown in Figure 3 The embodiment of the present application further includes a voltage limiting module 400; the voltage limiting module 400 is connected with the output terminal of the voltage follower module 300.
[0041] As shown in Figure 3 The voltage limiting module 400 includes a first diode D1 and a second diode D2. The negative electrode of the first diode D1 is connected with a power terminal, the positive electrode of the first diode D1 is connected with the negative electrode of the second diode D2 and the output terminal of the voltage follower module 300; the positive electrode of the second diode D2 is connected with a ground terminal. The power terminal outputs a 5V voltage to the negative electrode of the first diode D1.
[0042] The diodes in the voltage limiting module 400 limit the output amplitude of the voltage follower module 300, so that the output amplitude of the voltage follower module 300 is between -0.7V and 5.7V (greater than or equal to -0.7V and less than or equal to 5.7V), and the post-circuit is protected from overvoltage damage.
[0043] As shown in Figure 3 The embodiment of the present application further includes a filter module 500; the input terminal of the filter module 500 is connected with the voltage limiting module 400.
[0044] As shown in Figure 3 The filter module 500 includes a sixth-order Butterworth low-pass filter.
[0045] As shown in Figure 3As shown, the sixth-order Butterworth low-pass filter includes three parallel second-order Butterworth low-pass filters 501. By connecting three second-order Butterworth low-pass filters 501 in parallel, a sixth-order Butterworth low-pass filter can be obtained.
[0046] like Figure 3 As shown, the second-order Butterworth low-pass filter 501 includes: a first capacitor C1, a second capacitor C2, a fourth resistor R4, a fifth resistor R5 and a first amplifier A1. Among them, one end of the fourth resistor R4 is connected to the anode of the first diode D1, and the other end is connected to one end of the fifth resistor R5 and one end of the first capacitor C1. The other end of the fifth resistor R5 is connected to one end of the second capacitor C2 and the positive input terminal of the first amplifier A1. The other end of the first capacitor C1 is connected to the negative input terminal and output terminal of the first amplifier A1. The other end of the second capacitor C2 is connected to the ground terminal.
[0047] The Butterworth low-pass filter has the flattest response within the passband and can retain the original signal characteristics to the greatest extent while filtering out noise.
[0048] The output end of the filter module 500 is used to connect to the analog-to-digital converter ADC of the controller.
[0049] Below, as Figure 3 As shown, this application is further described.
[0050] The 12V DC bias voltage output by the constant current source 100 makes the signal (input signal) input by the sensor S a vibration signal V of -5V to 5V (greater than or equal to -5V and less than or equal to 5V) superimposed on the 12V DC bias. IN Since the input signal of sensor S is an AC signal of -5V to 5V (10Vpp, the difference between the maximum positive voltage and the minimum negative voltage is 10V), its actual amplitude range is 7V to 17V (greater than or equal to 7V and less than or equal to 17V) after superimposing a 12V DC bias.
[0051] The input signal is scaled by the sixth resistor R6 in the first voltage dividing unit 201 and the first resistor R1, the second resistor R2 and the third resistor R3 in the second voltage dividing unit 202. For example, when the input signal is 7V to 17V, the ratio of the sixth resistor R6 to one resistor (assuming the first resistor R1) in the second voltage dividing unit 202 is set to 4:1, i.e. R6:R1=4:1, so that the amplitude of the input signal is scaled to 1.75V to 4.25V (greater than or equal to 1.75V and less than or equal to 4.25V), which meets the 0V to 5V (greater than or equal to 0V and less than or equal to 5V) input range of the analog-to-digital converter ADC. At this time, since the direct current bias is scaled to 3V by the first voltage dividing unit 201 and the second voltage dividing unit 202 of the conditioning module 200, the scaled amplitude (the amplitude of the output signal of the analog-to-digital converter ADC) can be reduced by the bias to obtain an effective signal of -1.25V to 1.25V (greater than or equal to -1.25V and less than or equal to 1.25V) by software, and then multiplied by the scaling factor to obtain an effective vibration signal (input signal) with an original input amplitude of -5V to 5V.
[0052] The embodiments of the present application can extract an effective IEPE signal by voltage division of the resistors in the first voltage dividing unit 201 and the second voltage dividing unit 202; can match IEPE sensors with different sensitivities by changing the connection of the multiple connection ends of the first voltage dividing unit 201 and the second voltage dividing unit 202 in the switching unit 203; can improve signal stability by the voltage follower module 300; and can stably and reliably convert the amplitude of the IEPE sensor signal by the voltage limiting module 400 through the diode in the post-circuit overvoltage protection, so as to extract and stably convert the effective voltage signal of the IEPE sensor, thereby being able to adapt to IEPE sensors with different sensitivities and reducing the cost of the circuit.
[0053] In a second aspect, according to the embodiments of the present application, a vehicle-mounted controller is provided, which comprises the conditioning circuit for the IEPE acceleration sensor according to any one of the first aspect.
[0054] In a third aspect, according to the embodiments of the present application, a vehicle is provided, which comprises the vehicle-mounted controller according to the second aspect.
[0055] The benefit of the embodiment is that the accuracy of the voltage division is adjusted by the conditioning module, so as to adjust the amplitude of the input signal of the sensor, and the problem that different IEPE sensors have different sensitivities, there is a high voltage bias, and the acquisition range of the analog-to-digital converter ADC of the controller does not match is solved. The input signal is scaled by the resistance in the conditioning module, so as to scale the input amplitude of the input signal; the DC bias in the original signal can be filtered out by software calculation; by introducing an analog switch in the switching unit, the voltage division ratio of the resistors in the first voltage division unit and the second voltage division unit is adjusted, so that the sensitivity of different sensors can be matched; the voltage follower module can enhance the signal accuracy and stability; the voltage limiting module can protect the later stage circuit from overvoltage by introducing only two diodes. The embodiments of the application combine the characteristics of IEPE sensors and vehicle-mounted processors and the like, realize the stable voltage amplitude conditioning conversion of the IEPE sensor for the IEPE sensor and the vehicle-mounted processor, and have low cost.
[0056] The above described in the specification of the utility model is only the example of the utility model. The skilled in the art to which the utility model belongs can make various modifications or supplements or adopt similar ways to replace the described specific embodiments, as long as it does not deviate from the content of the specification of the utility model or exceed the range defined by the claims, and it shall belong to the protection scope of the utility model.
Claims
1. A conditioning circuit for an IEPE acceleration sensor, characterized in that, Comprising: a constant current source and a conditioning module; the constant current source is connected with a sensor and the conditioning module respectively; the conditioning module comprises a first voltage dividing unit, a switching unit and a second voltage dividing unit; one end of the first voltage dividing unit is connected with the constant current source and the sensor, and the other end is connected with one end of the switching unit; the other end of the switching unit is connected with any one of multiple connection ends of the second voltage dividing unit.
2. The conditioning circuit of claim 1, wherein, the second voltage dividing unit comprises a first resistor, a second resistor and a third resistor, one end of the first resistor, one end of the second resistor and one end of the third resistor are used to be connected with the other end of the switching unit.
3. The conditioning circuit of claim 1, wherein, Further comprising: a voltage follower module; a first input end of the voltage follower module is connected with the other end of the first voltage dividing unit, and a second input end of the voltage follower module is connected with an output end.
4. Conditioning circuit according to claim 3, characterized in that Further comprising: a voltage limiting module; the voltage limiting module is connected with the output end of the voltage follower module.
5. The conditioning circuit of claim 4, wherein, the voltage limiting module comprises a first diode and a second diode; a negative electrode of the first diode is connected with a power supply end, a positive electrode of the first diode is connected with a negative electrode of the second diode and an output end of the voltage follower module; a positive electrode of the second diode is connected with a ground end.
6. The conditioning circuit of claim 4, wherein, Further comprising: a filter module; an input end of the filter module is connected with the voltage limiting module.
7. The conditioning circuit of claim 6, wherein, the filter module comprises a six-order Butterworth low-pass filter.
8. The conditioning circuit of claim 7, wherein, the six-order Butterworth low-pass filter comprises three two-order Butterworth low-pass filters connected in parallel.
9. An in-vehicle controller characterized by comprising: Comprising the conditioning circuit for the IEPE acceleration sensor as claimed in any one of claims 1 to 8.
10. A vehicle characterized by comprising: Comprising the vehicle-mounted controller as claimed in claim 9.