Displacement sensor control circuit and displacement sensor

Abstract

The invention provides a displacement sensor control circuit and a displacement sensor. The displacement sensor control circuit comprises a capacitance oscillation unit, a control unit and an output unit. The first input end of the capacitance oscillation unit is connected with the first end of the variable capacitor, the second input end of the capacitance oscillation unit is connected with the second end of the variable capacitor, and the output end of the capacitance oscillation unit is connected with the input end of the output unit; the receiving end of the control unit is connected with the output end of the output unit. And the capacitance oscillation unit is used for outputting a pulse signal corresponding to the capacitance value to the output unit according to the capacitance value of the variable capacitor. And the output unit is used for adjusting the voltage signal of the output end based on the pulse signal. And the control unit is used for collecting the voltage signal and determining the relative position of the first capacitor plate and the second capacitor plate of the variable capacitor according to the voltage signal. According to the displacement sensor control circuit, the stability of the displacement sensor is improved, and the cost of the displacement sensor is reduced.

Description

Technical Field

[0001] The present application relates to sensor technology, and in particular to a displacement sensor control circuit and a displacement sensor. Background Art

[0002] The displacement sensor is used to determine the distance corresponding to the displacement change based on the measured displacement change, and further determine the pressure change corresponding to the distance change based on the distance change. Therefore, the displacement sensor can be used on equipment that requires pressure detection or distance detection. At present, thanks to the development of science and technology, the application fields of displacement sensors are becoming more and more extensive, for example, they can be used in robot clamping force detection, finger pressure detection, etc.

[0003] However, current displacement sensors have problems of poor stability or large size. Summary of the invention

[0004] The present application provides a displacement sensor control circuit and a displacement sensor, which are used to solve the problems of poor stability or large size of current displacement sensors.

[0005] In a first aspect, the present application provides a displacement sensor control circuit, comprising:

[0006] A capacitor oscillation unit, a control unit, and an output unit;

[0007] The first input end of the capacitor oscillation unit is connected to the first end of the variable capacitor, the second input end of the capacitor oscillation unit is connected to the second end of the variable capacitor, the output end of the capacitor oscillation unit is connected to the input end of the output unit; the receiving end of the control unit is connected to the output end of the output unit;

[0008] The capacitor oscillation unit is used to output a pulse signal corresponding to the capacitance value to the output unit according to the capacitance value of the variable capacitor, wherein the pulse signal is used to represent the relative position of the first capacitor plate and the second capacitor plate of the variable capacitor;

[0009] The output unit is used to adjust the voltage signal at its output end based on the pulse signal;

[0010] The control unit is used to collect the voltage signal and determine the relative position of the first capacitor plate and the second capacitor plate of the variable capacitor according to the voltage signal.

[0011] Optionally, the capacitive oscillation unit includes: a first comparator and a first resistor;

[0012] The first input terminal of the first comparator is connected to the first capacitor plate, the second input terminal of the first comparator is connected to the second capacitor plate, the output terminal of the first comparator is connected to the input terminal of the output unit, the first end of the first resistor is connected to the first capacitor plate, and the second end of the first resistor is connected to the output terminal of the first comparator.

[0013] Optionally, the output unit includes: at least one first capacitor, a first diode, and a second resistor;

[0014] The anode of the first diode is connected to the output end of the capacitor oscillation unit, the cathode of the first diode is connected to the first end of the second resistor, the second end of the second resistor is the output end of the output unit, the first end of the at least one first capacitor is connected to the second end of the second resistor, and the second end of the at least one first capacitor is grounded;

[0015] The first diode is used to receive the pulse signal corresponding to the capacitance value of the variable capacitor and prevent the pulse signal from flowing back;

[0016] The first capacitor is used to receive the pulse signal and be charged according to the pulse signal;

[0017] The second resistor is used to form an integration circuit with the at least one first capacitor.

[0018] Optionally, the displacement sensor control circuit further includes: a processing unit;

[0019] The input end of the processing unit is connected to the output end of the capacitor oscillation unit, the output end of the processing unit is connected to the input end of the output unit, and the first end of the processing unit is connected to the output end of the control unit;

[0020] The processing unit is used to convert the pulse signal output by the capacitor oscillation unit into a pulse signal less than or equal to a preset duty cycle threshold.

[0021] Optionally, the processing unit includes: a differentiation module and a comparison module;

[0022] The input end of the differential module is the input end of the processing unit, the output end of the differential module is connected to the input end of the comparison module, the output end of the comparison module is the output end of the processing unit, and the first end of the comparison module is the first end of the processing unit;

[0023] The differential module is used to obtain the pulse signal output by the capacitor oscillation unit and convert the pulse signal into a sharp pulse wave pulse signal;

[0024] The comparison module is used to convert the sharp pulse wave pulse signal into a pulse signal less than or equal to a preset duty cycle threshold.

[0025] Optionally, the differential module includes: a second capacitor and a second diode;

[0026] The first end of the second capacitor is the input end of the differential module, the second end of the second capacitor is the output end of the differential module, and the anode of the second diode and the cathode of the second diode are both connected to the second end of the second capacitor.

[0027] Optionally, the comparison module includes: a first reference voltage input submodule, a second comparator;

[0028] The first input end of the second comparator is the input end of the comparison module, the second input end of the second comparator is connected to the first reference voltage input submodule, and the output end of the second comparator is the output end of the comparison module;

[0029] The first reference voltage input submodule is used to provide a first reference voltage to the second comparator;

[0030] The second comparator is used to convert the sharp pulse wave pulse signal into a pulse signal less than or equal to a preset duty cycle threshold.

[0031] Optionally, also include:

[0032] The output terminal of the control unit is connected to the positive electrode of the power supply terminal of the second comparator, and the negative electrode of the power supply terminal of the second comparator is grounded;

[0033] The control unit is used to enable the second comparator.

[0034] Optionally, the displacement sensor control circuit further includes: an amplification unit;

[0035] The input end of the amplifying unit is connected to the output end of the output unit, and the output end of the amplifying unit is connected to the input end of the control unit;

[0036] The amplifying unit is used to amplify the voltage signal output by the output unit.

[0037] In a second aspect, the present application provides a displacement sensor, which includes a variable capacitor, a chip for obtaining the relative position of a first capacitor plate and a second capacitor plate of the variable capacitor, and a displacement sensor control circuit as described in any one of the first aspects.

[0038] The displacement sensor control circuit and displacement sensor provided in the present application connect a capacitor oscillation unit to two capacitor plates of a variable capacitor, the relative positions of the two capacitor plates determine the capacitance value of the variable capacitor, the capacitor oscillation unit outputs a corresponding pulse signal according to the capacitance value, and the output unit adjusts the voltage signal at its output end based on the pulse signal to determine the relative positions of the two capacitor plates through the voltage signal, thereby achieving measurement of displacement, thereby improving the stability of the displacement sensor, reducing the size of the displacement sensor, and reducing the manufacturing cost of the displacement sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0040] Figure 1 A schematic diagram of a displacement sensor control circuit provided in an embodiment of the present application;

[0041] Figure 2 A schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application;

[0042] Figure 3 A schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application;

[0043] Figure 4 A schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application;

[0044] Figure 5 A schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application;

[0045] Figure 6 A schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application;

[0046] Figure 7 A schematic diagram of converting a square wave into a sharp pulse wave provided in an embodiment of the present application;

[0047] Figure 8 A schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application;

[0048] Fig. 9 A schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application;

[0049] Fig.10 A schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application.

[0050] Description of reference numerals:

[0051] 100-capacitor oscillation unit; 200-control unit; 300-output unit; 400-variable capacitor; 410-first capacitor plate; 420-second capacitor plate; LT01-first comparator; R1-first resistor; C1-first capacitor; D1-first diode; R2-second resistor; 500-processing unit; 510-differential module; 520-comparison module; C2-second capacitor; D2-second diode; 521-first reference voltage input submodule; LT02-second comparator; 600-amplification unit; R16-first voltage divider resistor; R3-second voltage divider resistor; R4-second Three resistors; R5-fourth resistor; C3-third capacitor; R6-third voltage-dividing resistor; R7-fourth voltage-dividing resistor; C4-fourth capacitor; VCC1-first power supply terminal; VCC2-second power supply terminal; VCC3-third power supply terminal; R8-fifth voltage-dividing resistor; R9-sixth voltage-dividing resistor; R10-fifth resistor; C5-fifth capacitor; R11-sixth resistor; M1-first MOS tube; M2-second MOS tube; EN-enable signal; 700-delay module; 800-power module; R12-seventh resistor; R13-eighth resistor; R14-ninth resistor; R15-tenth resistor.

[0052] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0053] In order to make the objectives, technical solutions and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0054] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0055] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0056] In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0057] At present, when displacement sensors are applied to tiny distance measurements, for example, when pressure sensors measure pressure based on tiny distances measured by displacement sensors in the pressure sensors, they mainly include sliding resistance type, magnetic Hall type, grating type, micro-electro-mechanical system (MEMS) and other forms.

[0058] However, for the sliding resistor displacement sensor, the resistance value of the sliding resistor is less stable and has a shorter lifespan. As the number of uses and the use time increase, the resistance value of the sliding resistor changes greatly, so the measurement accuracy of the sliding resistor displacement sensor will decrease. For the magnetoelectric or Hall displacement sensor, the distance is mainly measured based on the change of the magnetic field. If there is external electromagnetic interference near the displacement sensor, it will affect the change of the magnetic field in the displacement sensor and reduce the measurement accuracy of the magnetoelectric or Hall displacement sensor. The grating displacement sensor refers to a sensor that uses the principle of grating fringe to measure displacement. To achieve the detection sensitivity and resolution of the grating displacement sensor, a high-performance monochromator or spectrometer must be used. Therefore, the grating displacement sensor has the problem of large size and high cost. The MEMS displacement sensor refers to a high-tech device with a size of several millimeters or even smaller. Its internal structure is generally in the micrometer or even nanometer level. It is an independent intelligent system, so its cost is also high.

[0059] Therefore, many current displacement sensors have problems such as poor stability, large size, or high manufacturing cost.

[0060] In view of this, the present application provides a displacement sensor control circuit. The capacitance value of the variable capacitor is determined by the relative position of two capacitor plates of the variable capacitor, and the voltage signal corresponding to the relative position of the two capacitor plates output by the control circuit is determined according to the pulse signal corresponding to the capacitance value, and the relative position of the two capacitor plates is determined by the voltage signal to achieve displacement measurement, thereby improving the stability of the displacement sensor, reducing the size of the displacement sensor, and reducing the manufacturing cost of the displacement sensor.

[0061] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0062] Figure 1 This is a schematic diagram of a displacement sensor control circuit provided in an embodiment of the present application. Figure 1 As shown, the displacement sensor control circuit includes: a capacitor oscillation unit 100 , a control unit 200 , and an output unit 300 .

[0063] Wherein, the first input end of the capacitor oscillation unit 100 is connected to the first end of the variable capacitor 400, and the second input end of the capacitor oscillation unit 100 is connected to the second end of the variable capacitor 400. The variable capacitor 400 includes a first capacitor plate 410 and a second capacitor plate 420, the first end of the variable capacitor 400 can be any one of the two capacitor plates, and the second end of the variable capacitor 400 can be another capacitor plate. The first capacitor plate 410 and the second capacitor plate 420 can be located on the electronic device where the displacement sensor is located for detecting distance, or on a component for detecting pressure, for example, can be located on the manipulator of an intelligent robot, for detecting the clamping force of the robot, or detecting the finger pressure on the manipulator, etc. When the relative position of the first capacitor plate 410 and the second capacitor plate 420 changes, the capacitance value of the variable capacitor 400 will also change accordingly. The output end of the capacitor oscillation unit 100 is connected to the input end of the output unit 300, and the receiving end of the control unit 200 is connected to the output end of the output unit 300.

[0064] The capacitor oscillation unit 100 is used to output a pulse signal corresponding to the capacitance value to the output unit 300 according to the capacitance value of the variable capacitor 400. The pulse signal is used to characterize the relative position of the first capacitor plate 410 and the second capacitor plate 420 of the variable capacitor 400. For different capacitance values ​​of the variable capacitor 400, the pulse signal output by the capacitor oscillation unit is different. Exemplarily, within the first preset time length of 1 microsecond, for the capacitance value 1, the capacitor oscillation unit outputs a pulse signal with 100 square waves within the 1 microsecond, and for the capacitance value 2 different from the capacitance value 1, the capacitor oscillation unit outputs a pulse signal with 105 square waves within the 1 microsecond.

[0065] The output unit 300 is used to adjust the voltage signal at its output end based on the pulse signal. The output unit 300 can receive the pulse signal and adjust the voltage signal output by the circuit of the output unit 300 according to the pulse signal.

[0066] In a possible implementation, the voltage signal outputted from the output end is determined by the number of pulse waves of the pulse signal within the first preset time length, and pulse signals with different numbers of pulse waves within the first preset time length correspond to different voltage signals. For example, the output unit 300 can receive the pulse signal and charge the capacitor in the output unit 300 according to the pulse signal, and determine the voltage signal outputted from the output end corresponding to the number of pulse waves of the pulse signal according to the number of charges in the capacitor.

[0067] Another possible implementation method is to determine the voltage signal output from the output end according to the interval between the waveforms of the pulse wave of the pulse signal and / or the wavelength of the pulse wave, and to determine the voltage signal output from the output end for different intervals between the waveforms of the pulse wave and / or different wavelengths of the pulse wave.

[0068] The control unit 200 is used to collect the voltage signal, and determine the relative position of the first capacitor plate 410 and the second capacitor plate 420 of the variable capacitor 400 according to the voltage signal. The control unit 200 can determine the relative position of the first capacitor plate 410 and the second capacitor plate 420 of the variable capacitor 400 according to the voltage signal and the mapping relationship between the voltage signal and the relative position of the first capacitor plate 410 and the second capacitor plate 420 of the variable capacitor 400, and further determine the distance measured by the first capacitor plate 410 and the second capacitor plate 420. The mapping relationship can be preset in the control unit 200, and the mapping relationship can be, for example, a functional relationship, or a mapping table, etc.

[0069] The structure provided by the present application connects the capacitor oscillation unit 100 to the two capacitor plates of the variable capacitor 400, the relative positions of the two capacitor plates determine the capacitance value of the variable capacitor 400, the capacitor oscillation unit 100 outputs a corresponding pulse signal according to the capacitance value, and the output unit 300 adjusts the voltage signal at its output end based on the pulse signal to determine the relative positions of the two capacitor plates through the voltage signal, thereby achieving measurement of displacement, thereby improving the stability of the displacement sensor, reducing the size of the displacement sensor, and reducing the manufacturing cost of the displacement sensor.

[0070] The circuit structures of the capacitor oscillation unit 100 and the output unit 300 are described in detail below.

[0071] Figure 2 This is a schematic diagram of another displacement sensor control circuit provided in an embodiment of the present application. Figure 2 As shown, the displacement sensor control circuit is Figure 1 Based on the circuit structure shown, the capacitor oscillation unit 100 includes: a first comparator LT01.

[0072] The first input terminal of the first comparator LT01 is connected to the first capacitor plate 410, the second input terminal of the first comparator LT01 is connected to the second capacitor plate 420, the output terminal of the first comparator LT01 is connected to the input terminal of the output unit 300, the first end of the first resistor R1 is connected to the first capacitor plate 410, and the second end of the first resistor R1 is connected to the output terminal of the first comparator LT01.

[0073] The variable capacitor 400 can determine the capacitance value of the variable capacitor 400 according to the relative position between the first capacitor plate 410 and the second capacitor plate 420. The capacitance value can be calculated as shown in the following formula (1):

[0074] C=εS / d (1)

[0075] Wherein, C is the capacitance value of the variable capacitor 400, ε is the dielectric constant of the medium between the capacitor plates, S is the facing area between the first capacitor plate 410 and the second capacitor plate 420, and d is the distance between the first capacitor plate 410 and the second capacitor plate 420. This application is introduced by taking S fixed as an example, so the capacitance value of the variable capacitor 400 is mainly affected by the distance between the first capacitor plate 410 and the second capacitor plate 420. The larger the distance, the smaller the capacitance value. Therefore, when the relative position between the first capacitor plate 410 and the second capacitor plate 420 is different, the capacitance value of the variable capacitor 400 is also different.

[0076] The variable capacitor 400 and the first resistor R1 form an oscillation circuit so that the voltage output on the first capacitor plate 410 and the voltage output on the second capacitor plate 420 change. The first comparator LT01 outputs a level corresponding to the change in the magnitude relationship of the voltage according to the magnitude relationship between the voltage at its first input terminal and the voltage at its second input terminal, as well as the change of the oscillation circuit. For example, when the voltage at the first input terminal is higher, a high level is output, and when the voltage at the second input terminal is higher, a low level is output. Further, according to the change of the oscillation circuit, the pulse signal expressed as a rectangular wave can be output. When the capacitance value of the variable capacitor 400 is different, the interval between the waveforms of the pulse wave, and / or the wavelength of the pulse wave, and the number of pulse waves output within the first preset duration are all different.

[0077] In one possible implementation, Figure 2 As shown, the capacitive oscillation unit 100 may further include: at least one of a first voltage-dividing resistor R16, a second voltage-dividing resistor R3, a third resistor R4, a fourth resistor R5, and a third capacitor C3.

[0078] Exemplarily, the first end of the first voltage-dividing resistor R16 is connected to the first power supply terminal (Volt Current Condenser, VCC) VCC1, and the second end of the first voltage-dividing resistor R16 is connected to the first end of the second voltage-dividing resistor R3. The first end of the second voltage-dividing resistor R3 is connected to the second end of the first voltage-dividing resistor R16 and the first input terminal of the first comparator LT01, and the second end of the second voltage-dividing resistor R3 is connected to the first capacitor plate 410. The first voltage-dividing resistor R16 and the second voltage-dividing resistor R3 play a voltage-dividing role in the loop of the capacitor oscillation unit 100. Among them, the first power supply terminal VCC1 is also directly connected to the power supply terminal of the first comparator LT01 to power the first comparator LT01.

[0079] The first end of the third resistor R4 is connected to the second end of the first voltage-dividing resistor R16, or the first end of the second voltage-dividing resistor R3, and the second end of the third resistor R4 is connected to the output end of the first comparator LT01. The third resistor R4 forms a feedback circuit of the first comparator LT01 to prevent the pulse signal output by the first comparator LT01 from jumping, thereby improving the stability of the output of the first comparator LT01.

[0080] The first end of the fourth resistor R5 is connected to the second capacitor plate 420, and the second end is connected to the second input end of the first comparator LT01 to perform electrostatic discharge (ESD) protection on the positive circuit in the capacitor oscillation unit 100. Since the first capacitor plate 410 and the second capacitor plate 420 of the variable capacitor 400 are fixed to the outside of the device in which the displacement sensor control circuit is deployed, they may be affected by ESD. Therefore, adding the fourth resistor R5 here can reduce the influence of the voltage formed by the external ESD on the chip input pin of the first comparator LT01.

[0081] The first end of the third capacitor C3 is connected to the output end of the first comparator LT01, and the second end is grounded. The third capacitor C3 is used to perform peak filtering on the pulse signal output by the first comparator LT01 to make the pulse signal output by the first comparator LT01 more stable.

[0082] In the following, taking the number of pulse waves of the pulse signal within the first preset time length as an example, determining the voltage signal outputted from the output end thereof, Figure 3 This is a schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application. Figure 3 As shown, the displacement sensor control circuit is Figure 1 Based on the circuit structure shown, the output unit 300 includes: at least one first capacitor C1 and a first diode D1.

[0083] The anode of the first diode D1 is connected to the output end of the capacitor oscillation unit 100, the cathode of the first diode D1 is the output end of the output unit 300, the first end of the at least one first capacitor C1 is connected to the cathode of the first diode D1, and the second end of the at least one first capacitor C1 is grounded;

[0084] The first diode D1 is used to receive the pulse signal corresponding to the capacitance value of the variable capacitor 400 and prevent the pulse signal from flowing back. The first capacitor C1 is used to receive the pulse signal obtained from the cathode of the first diode D1, and charge the first capacitor C1 according to the pulse signal, and store the charge corresponding to the pulse signal in the first capacitor C1. Optionally, the number and capacitance value of the first capacitor C1 can be determined according to actual needs. For example, one first capacitor C1 can be used, or multiple first capacitors C1 can be used, and this application does not limit this.

[0085] When the first capacitor C1 is charged according to the pulse signal, the amount of charge stored in the first capacitor C1 will change according to the pulse signal. Further, the voltage signal in the circuit of the output unit 300 will change based on the amount of charge stored in the first capacitor C1, so that the output unit 300 has the function of adjusting the voltage signal it outputs according to the pulse signal.

[0086] In one possible implementation, Figure 3 As shown, the output unit 300 may further include: a second resistor R2.

[0087] The first end of the second resistor R2 is connected to the cathode of the first diode D1, the second end of the second resistor R2 is the output end of the output unit 300, and the first end of at least one first capacitor C1 is connected to the second end of the second resistor R2. The second resistor R2 is used to form an integration circuit with the at least one first capacitor C1, and the integration circuit converts the pulse signal into a voltage signal for analog output.

[0088] Optionally, after the output unit 300, the displacement sensor control circuit Figure 1 On the basis of the circuit structure shown, an amplifying unit 600 may also be included. The input end of the amplifying unit 600 is connected to the output end of the output unit 300, and the output end of the amplifying unit 600 is connected to the input end of the control unit 200. The amplifying unit 600 is used to amplify the voltage signal output by the output unit 300 so that the voltage signal meets the resolution required by the control unit 200 when sampling. The amplifying unit 600 can be any existing amplifier, and this application does not limit this.

[0089] The structure provided by the present application converts the relative position of the first capacitor plate 410 and the second capacitor plate 420 into a pulse signal through common electrical components with low cost such as variable capacitors, comparators, diodes, resistors, etc., and outputs a corresponding voltage signal according to the pulse signal, so that the relative position of the first capacitor plate 410 and the second capacitor plate 420 can be determined based on the collected voltage signal, and the position of displacement measurement is achieved, avoiding the use of sliding resistors, magnetoelectric devices, MEMS and other devices, thereby avoiding the defects of existing displacement sensors, thereby improving the stability of the displacement sensor, reducing the size of the displacement sensor, and reducing the manufacturing cost of the displacement sensor.

[0090] Figure 4 This is a schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application. Figure 4 As shown, the displacement sensor control circuit is Figure 1 Based on the circuit structure shown, it may further include: a processing unit 500 .

[0091] The input end of the processing unit 500 is connected to the output end of the capacitor oscillation unit 100 , the output end of the processing unit 500 is connected to the input end of the output unit 300 , and the first end of the processing unit 500 is connected to the output end of the control unit 200 .

[0092] The processing unit 500 is used to convert the pulse signal output by the capacitor oscillation unit 100 into a pulse signal less than or equal to a preset duty cycle threshold. The preset duty cycle can be determined according to actual needs. By reducing the duty cycle of the pulse signal, the amount of charge when the first capacitor C1 in the output unit 300 is charged can be effectively reduced, so that the first capacitor C1 with a smaller capacitance value and a smaller volume can be used, thereby reducing the volume and cost of the first capacitor C1.

[0093] One possible implementation method is to obtain only the rising edge change of the high and low level transition moment of the pulse signal output by the capacitor oscillation unit 100 to form a square wave corresponding to the rising edge change, so as to reduce the wavelength of the pulse wave between the rising edge change and the falling edge change of the pulse signal, thereby realizing the function of reducing the duty cycle of the pulse signal.

[0094] In this implementation, Figure 5 This is a schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application. Figure 5 As shown, the displacement sensor control circuit is Figure 1 Based on the circuit structure shown, the processing unit 500 includes: a differentiation module 510 and a comparison module 520 .

[0095] The input end of the differential module 510 is the input end of the processing unit 500 , the output end of the differential module 510 is connected to the input end of the comparison module 520 , the output end of the comparison module 520 is the output end of the processing unit 500 , and the first end of the comparison module 520 is the first end of the processing unit 500 .

[0096] The differential module 510 is used to obtain the pulse signal output by the capacitor oscillation unit 100 and convert the pulse signal into a sharp pulse wave pulse signal. The differential module 510 can separate the rising edge and falling edge changes of each pulse wave in the pulse signal to convert the square wave-shaped pulse wave into a sharp pulse wave corresponding to the rising edge change of the square wave and a sharp pulse wave pulse signal corresponding to the falling edge change of the square wave. The differential module 510 can also take out the sharp pulse wave pulse signal corresponding to the falling edge change of the square wave, so that the sharp pulse wave pulse signal only includes the sharp pulse wave corresponding to the rising edge change of the square wave.

[0097] The comparison module 520 is used to convert the sharp pulse wave pulse signal into a pulse signal less than or equal to a preset duty cycle threshold. The comparison module 520 can determine the pulse signal less than or equal to the preset duty cycle threshold corresponding to the sharp pulse wave corresponding to the rising edge change according to the wavelength of the sharp pulse wave corresponding to the rising edge change in the sharp pulse wave pulse signal, and the pulse signal less than or equal to the preset duty cycle threshold can be expressed as a square wave less than or equal to the preset duty cycle threshold.

[0098] Through this implementation, the displacement sensor control circuit can separate the rising edge change of the pulse signal through the rising edge change and the falling edge change of the pulse signal output by the capacitor oscillation unit 100, and convert the pulse signal into a pulse signal less than or equal to the preset duty cycle threshold according to the rising edge change. This implementation can effectively reduce the amount of charge when the first capacitor C1 in the output unit 300 is charged, so that the first capacitor C1 with a smaller capacitance value and a smaller volume can be used, thereby reducing the volume and cost of the first capacitor C1.

[0099] The specific circuit structures of the differential module 510 and the comparison module 520 included in the processing unit 500 are described in detail below by taking an example.

[0100] Figure 6 This is a schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application. Figure 6 As shown, the differential module 510 may include: a second capacitor C2, a second diode D2;

[0101] The first end of the second capacitor C2 is the input end of the differential module 510, the second end of the second capacitor C2 is the output end of the differential module 510, and the anode of the second diode D2 and the cathode of the second diode D2 are both connected to the second end of the second capacitor C2.

[0102] Among them, by utilizing the principle of blocking direct current and passing alternating current of the second capacitor C2, the pulse signal output by the capacitor oscillation unit 100 can only pass the alternating current of the pulse signal, that is, the rising edge change and the falling edge change of the pulse signal when passing through the second capacitor C2, thereby removing the direct current between the rising edge change and the falling edge change of each pulse wave in the pulse signal. At this time, the pulse wave of the pulse signal is converted from a square wave into a positive sharp pulse wave corresponding to the positive voltage corresponding to the rising edge change, and a reverse sharp pulse wave corresponding to the reverse voltage corresponding to the falling edge change. Figure 7 A schematic diagram of converting a square wave into a sharp pulse wave provided in an embodiment of the present application. Figure 7As shown, each square wave of the pulse signal will be converted into corresponding forward sharp pulse wave and reverse sharp pulse wave, but this conversion will not affect the interval between the two pulse waves of the pulse signal. Therefore, the number of pulse waves of the pulse signal is also the same, realizing the function of reducing the duty cycle of the pulse signal without affecting the number of pulse waves of the pulse signal.

[0103] The second diode D2 is used in the loop of the differential module 510. According to the unidirectional conductivity of the diode, it can suppress the reverse voltage of the reverse spike pulse wave corresponding to the falling edge change, so as to eliminate the reverse spike pulse wave corresponding to the falling edge change, and convert the pulse signal output by the capacitor oscillation unit 100 into a spike pulse wave pulse signal including only the rising edge change of the pulse signal.

[0104] In one possible implementation, Figure 6 As shown, the differential module 510 may further include: at least one of a third voltage-dividing resistor R6, a fourth voltage-dividing resistor R7, and a fourth capacitor C4.

[0105] The first end of the third voltage-dividing resistor R6 is connected to the second end of the second capacitor C2, the second end of the third voltage-dividing resistor R6 is the output end of the differential unit, and is linked to the first end of the fourth voltage-dividing resistor R7 and the first end of the fourth capacitor C4, the second end of the fourth voltage-dividing resistor R7 and the second end of the fourth capacitor C4 are both connected to the anode of the second diode D2, and the second end of the fourth voltage-dividing resistor R7 and the second end of the fourth capacitor C4 are grounded.

[0106] Among them, the third voltage-dividing resistor R6 and the fourth voltage-dividing resistor R7 are used to divide the voltage in the loop of the differential module 510 to control the voltage in the loop of the differential module 510. The third voltage-dividing resistor R6 and the fourth voltage-dividing resistor R7 can be set according to actual needs, and the resistance values ​​of the third voltage-dividing resistor R6 and the fourth voltage-dividing resistor R7 can also be determined according to actual needs. The fourth capacitor C4 is used to perform burr processing on the sharp pulse wave pulse signal passing through the second capacitor C2, and its effect is similar to the third capacitor C3 mentioned above, which will not be repeated here.

[0107] Figure 8 This is a schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application. Figure 8 As shown, the comparison module 520 may include: a first reference voltage input submodule 521 and a second comparator LT02.

[0108] The first input terminal of the second comparator LT02 is the input terminal of the comparison module 520 , the second input terminal of the second comparator LT02 is connected to the first reference voltage input submodule 521 , and the output terminal of the second comparator LT02 is the output terminal of the comparison module 520 .

[0109] The first reference voltage input submodule 521 is used to provide a first reference voltage to the second comparator LT02, and the first reference voltage is lower than the maximum voltage of the sharp pulse wave pulse signal received by the first input terminal of the second comparator LT02 and is greater than 0. Optionally, the first reference voltage input submodule 521 can be as follows Figure 8 As shown, it is realized by the second power supply terminal VCC2, the fifth voltage-dividing resistor R8 and the sixth voltage-dividing resistor R9. The first end of the fifth voltage-dividing resistor R8 is connected to the second power supply terminal VCC2, and the second end is connected to the first end of the sixth voltage-dividing resistor R9 and the second end of the second comparator LT02 respectively. The second end of the sixth voltage-dividing resistor R9 is grounded.

[0110] In this implementation, a filter can also be formed by the fifth resistor R10 and the fifth capacitor C5 to stabilize the first reference voltage output by the first reference voltage input submodule 521. Specifically, the first end of the fifth resistor R10 is connected to the second end of the fifth voltage-dividing resistor R8 or the first end of the sixth voltage-dividing resistor R9, and is connected to the first end of the fifth capacitor C5, the second end of the fifth resistor R10 is connected to the second input end of the second comparator LT02, and the second end of the fifth capacitor C5 is grounded. Optionally, a ninth resistor R14 can be added before the first input end of the second comparator LT02, and / or a sixth resistor R11 can be added to the output end of the second comparator LT02. The first end of the sixth resistor R11 is connected to the output end of the second comparator LT02, and the second end is grounded. The first end of the ninth resistor R14 is the input end of the comparison module 520, and the second end is connected to the first input end of the second comparator LT02. The sixth resistor R11 is used to simulate the load so that the output load of the comparison module 520 matches the load of the subsequent circuit (output unit 300). The ninth resistor R14 is used to match the input resistance of the second comparator LT02 to prevent the signal output of the front-end differential module 510 from being affected.

[0111] The second comparator LT02 is used to convert the sharp pulse wave pulse signal into a pulse signal less than or equal to a preset duty cycle threshold. When the pulse signal received by the first input terminal of the second comparator LT02 is greater than or equal to the first reference voltage of the second terminal, the output terminal of the second comparator LT02 outputs a high level; when the pulse signal received by the first input terminal of the second comparator LT02 is less than the first reference voltage of the second terminal, the output terminal of the second comparator LT02 outputs a low level. Through the level output by the second comparator LT02, the sharp pulse wave pulse signal can be reconverted into a new square wave pulse signal. The new square wave pulse signal only represents the rising edge change of the processed square wave pulse signal. Therefore, the interval between each pulse wave in the new square wave pulse signal is larger, that is, the duty cycle is lower. According to the above principle, the second comparator LT02 can realize the conversion of the sharp pulse wave pulse signal into a pulse signal less than or equal to the preset duty cycle threshold.

[0112] The structure provided in the present application reduces the duty cycle of the pulse signal received by the output unit 300 by connecting the differential module 510 and the comparison module 520 after the capacitor oscillation unit, and reduces the amount of charge when the first capacitor C1 in the output unit 300 is charged, so that the first capacitor C1 with a smaller capacitance value and / or a smaller volume can be selected, thereby further reducing the volume and / or manufacturing cost of the displacement sensor.

[0113] When the displacement sensor control circuit is deployed on an intelligent robot or an intelligent device that needs to detect pressure, it may be necessary to obtain the displacement distance detected by the displacement sensor control circuit multiple times. Therefore, in a possible implementation, the control unit 200 in the displacement sensor control circuit can also be deployed in the following manner. Fig. 9 This is a schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application. Fig. 9 As shown, the control unit 200 may also be connected to the second comparator LT02 and the delay module 700 .

[0114] The output end of the control unit 200 is connected to the positive electrode of the power supply end of the second comparator LT02, and the negative electrode of the power supply end of the second comparator LT02 is grounded. The output end of the control unit 200 is also connected to the input end of the delay module 700, and the output end of the delay module 700 is connected to the first end of the first metal-oxide-semiconductor field effect transistor (Metal Oxide Semiconductor, MOS) M1, the second end of the first MOS transistor M1 is connected to the output end of the output module, and the third end of the first MOS transistor M1 is grounded.

[0115] The control unit 200 is used to enable the second comparator LT02 to control whether the second comparator LT02 outputs a pulse signal less than or equal to a preset duty cycle threshold, so that the control module can turn on or off the output of the second comparator LT02 according to actual needs. For example, it can be achieved by outputting an enable signal EN, and the enable signal EN can, for example, control a power module 800 connected to the positive pole of the power supply terminal of the second comparator LT02. When the control unit 200 outputs the enable signal EN, the power module 800 is turned on to supply power to the second comparator LT02, so that the second comparator LT02 can output a pulse signal less than or equal to the preset duty cycle threshold.

[0116] For example, Fig. 9 As shown, the power module 800 may include a third power supply terminal VCC3, a second MOS tube M2, a seventh resistor R12, and an eighth resistor R13. The enable signal EN is connected to the first end of the second MOS tube M2, the third power supply terminal VCC3 is connected to the second end of the second MOS tube M2, the third end of the second MOS tube M2 is connected to the first end of the seventh resistor R12, the second end of the seventh resistor R12 is grounded, the first end of the eighth resistor R13 is connected to the second end of the second MOS tube M2, and the second end of the eighth resistor R13 is connected to the first end of the second MOS tube M2.

[0117] The function of the seventh resistor R12 is the same as that of the sixth resistor R11, which will not be described again. The eighth resistor R13 is used to provide a bias voltage for the gate and source of the second MOS transistor M2 to establish a voltage difference between the gate and source of the second MOS transistor M2.

[0118] The delay module 700 is used to delay the output of the enable signal EN to the first end of the first MOS tube M1, that is, within the second preset time length after the control unit 200 stops outputting the enable signal EN, the enable signal EN can still be output to the first end of the first MOS tube M1, and when the first end of the first MOS tube M1 can receive the enable signal EN, the first MOS tube M1 is disconnected, and when the enable signal EN cannot be received, the first MOS tube M1 is turned on, so as to release the charge in the first capacitor C1 by turning on the first MOS tube M1, that is, to discharge the first capacitor C1, so that the first capacitor C1 can repeat the aforementioned charging when receiving the pulse signal next time. Among them, the delay module 700 can be any existing delay module 700, such as a delay circuit currently formed by resistors and capacitors, and the prior art can be referred to here, and the present application does not limit this.

[0119] Optionally, the delay module 700 may further include a tenth resistor R15 between the delay module 700 and the output unit. The first end of the tenth resistor R15 is connected to the first end of the first capacitor C1 and the second end of the second resistor R2, and the second end of the tenth resistor R15 is connected to the second end of the first MOS tube M1. The tenth resistor R15 is used as a discharge resistor to adjust the discharge current.

[0120] When the control module needs to collect the voltage signal of the output unit 300 (when displacement monitoring is required), the control module outputs an enable signal EN, and the enable signal EN turns on the power module 800 that supplies power to the second comparator LT02, so that the second comparator LT02 can output a pulse signal less than or equal to the preset duty cycle threshold to the output module. The output module charges at least one first capacitor C1 in the output module based on the received pulse signal less than or equal to the preset duty cycle threshold, and adjusts the voltage signal output by the output end of the output module according to the capacitance value of the at least one first capacitor C1.

[0121] Wherein, each time the control module outputs the enable signal EN, it continuously outputs the second preset duration. For example, if the second preset duration is 10 microseconds, the control module will output the enable signal EN for 10 microseconds when it is necessary to collect the voltage signal of the output unit 300, and after 10 microseconds, the output of the enable signal EN will be disconnected. The second preset duration can be determined according to actual needs, for example, according to the charge that the first capacitor C1 can carry, and the present application does not limit this.

[0122] The control module can sample the voltage signal outputted from the output terminal of the output module while disconnecting the output of the enable signal EN, so as to obtain a voltage signal corresponding to the relative position of the first capacitor plate 410 and the second capacitor plate 420 of the variable capacitor 400. The control module can determine the relative position of the first capacitor plate 410 and the second capacitor plate 420 according to the voltage signal and the mapping relationship between the voltage signal and the relative position of the first capacitor plate 410 and the second capacitor plate 420 of the variable capacitor 400, and can further determine the position change amount of the relative position of the first capacitor plate 410 and the second capacitor plate 420 according to the relative position of the first capacitor plate 410 and the second capacitor plate 420 obtained last time, so as to realize the function of displacement detection.

[0123] The enable signal EN is transmitted to the first end of the first MOS tube M1 through the delay module 700, and the enable signal EN output to the first end of the first MOS tube M1 is maintained within the third preset time after the control module disconnects the output of the enable signal EN, so as to keep the first MOS tube M1 in a disconnected state, and ensure the stability of the voltage signal when the control module samples the voltage signal output from the output end of the output module. When the control module disconnects the output of the enable signal EN for the third preset time, the delay module 700 disconnects the enable signal EN output to the first end of the first MOS tube M1, and turns on the first MOS tube M1, so as to release the charge in the first capacitor C1, that is, to discharge the first capacitor C1, so that the first capacitor C1 can repeat the aforementioned charging when receiving the pulse signal next time.

[0124] The control module may include a control chip, which may be a central processing unit (CPU) of the electronic device where the displacement sensor control circuit is located, or a microcontroller unit 200 (MCU) or other chip capable of realizing the above processing functions. For example, if the electronic device is an intelligent robot, the control chip may be the CPU of the intelligent robot, or may be an MCU that only processes the displacement sensor control circuit to realize the displacement detection function, etc., and this application does not limit this.

[0125] For ease of understanding, all the structures described in the above structural embodiments are integrated into Fig.10 An exemplary display is given in. Fig.10 This is a schematic diagram of the structure of another displacement sensor control circuit provided in an embodiment of the present application. Fig.10 The connection relationship and functions of the various units, modules, and electronic components are the same as those described in the previous embodiments and will not be repeated here.

[0126] On the other hand, an embodiment of the present application also provides a displacement sensor, which includes the variable capacitor 400 mentioned in any of the aforementioned embodiments, a chip for obtaining the relative position of the first capacitor plate 410 and the second capacitor plate 420 of the variable capacitor 400, and the displacement sensor control circuit in any of the aforementioned embodiments. The technical effect thereof is similar to that of the aforementioned displacement sensor control circuit, which will not be repeated here.

[0127] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0128] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A displacement sensor control circuit, characterized in that: The displacement sensor control circuit includes: a capacitor oscillation unit, a control unit, and an output unit; The first input end of the capacitor oscillation unit is connected to the first end of the variable capacitor, the second input end of the capacitor oscillation unit is connected to the second end of the variable capacitor, the output end of the capacitor oscillation unit is connected to the input end of the output unit; the receiving end of the control unit is connected to the output end of the output unit; The capacitor oscillation unit is used to output a pulse signal corresponding to the capacitance value to the output unit according to the capacitance value of the variable capacitor, wherein the pulse signal is used to represent the relative position of the first capacitor plate and the second capacitor plate of the variable capacitor; The output unit is used to adjust the voltage signal at its output end based on the pulse signal; The control unit is used to collect the voltage signal and determine the relative position of the first capacitor plate and the second capacitor plate of the variable capacitor according to the voltage signal.

2. The circuit according to claim 1, characterized in that The capacitive oscillation unit comprises: a first comparator and a first resistor; The first input terminal of the first comparator is connected to the first capacitor plate, the second input terminal of the first comparator is connected to the second capacitor plate, the output terminal of the first comparator is connected to the input terminal of the output unit, the first end of the first resistor is connected to the first capacitor plate, and the second end of the first resistor is connected to the output terminal of the first comparator.

3. The circuit according to claim 1, characterized in that The output unit includes: at least one first capacitor, a first diode, and a second resistor; The anode of the first diode is connected to the output end of the capacitor oscillation unit, the cathode of the first diode is connected to the first end of the second resistor, the second end of the second resistor is the output end of the output unit, the first end of the at least one first capacitor is connected to the second end of the second resistor, and the second end of the at least one first capacitor is grounded; The first diode is used to receive the pulse signal corresponding to the capacitance value of the variable capacitor and prevent the pulse signal from flowing back; The first capacitor is used to receive the pulse signal and be charged according to the pulse signal; The second resistor is used to form an integration circuit with the at least one first capacitor.

4. The circuit according to any one of claims 1 to 3, characterized in that: The displacement sensor control circuit further includes: a processing unit; The input end of the processing unit is connected to the output end of the capacitor oscillation unit, the output end of the processing unit is connected to the input end of the output unit, and the first end of the processing unit is connected to the output end of the control unit; The processing unit is used to convert the pulse signal output by the capacitor oscillation unit into a pulse signal less than or equal to a preset duty cycle threshold.

5. The circuit according to claim 4, characterized in that The processing unit includes: a differentiation module and a comparison module; The input end of the differential module is the input end of the processing unit, the output end of the differential module is connected to the input end of the comparison module, the output end of the comparison module is the output end of the processing unit, and the first end of the comparison module is the first end of the processing unit; The differential module is used to obtain the pulse signal output by the capacitor oscillation unit and convert the pulse signal into a sharp pulse wave pulse signal; The comparison module is used to convert the sharp pulse wave pulse signal into a pulse signal less than or equal to a preset duty cycle threshold.

6. The circuit according to claim 5, characterized in that The differential module includes: a second capacitor and a second diode; The first end of the second capacitor is the input end of the differential module, the second end of the second capacitor is the output end of the differential module, and the anode of the second diode and the cathode of the second diode are both connected to the second end of the second capacitor.

7. The circuit according to claim 5, characterized in that The comparison module comprises: a first reference voltage input submodule and a second comparator; The first input end of the second comparator is the input end of the comparison module, the second input end of the second comparator is connected to the first reference voltage input submodule, and the output end of the second comparator is the output end of the comparison module; The first reference voltage input submodule is used to provide a first reference voltage to the second comparator; The second comparator is used to convert the sharp pulse wave pulse signal into a pulse signal less than or equal to a preset duty cycle threshold.

8. The circuit according to claim 7, characterized in that Also includes: The output terminal of the control unit is connected to the positive electrode of the power supply terminal of the second comparator, and the negative electrode of the power supply terminal of the second comparator is grounded; The control unit is used to enable the second comparator.

9. The circuit according to claim 1, characterized in that The displacement sensor control circuit further includes: an amplification unit; The input end of the amplifying unit is connected to the output end of the output unit, and the output end of the amplifying unit is connected to the input end of the control unit; The amplifying unit is used to amplify the voltage signal output by the output unit.

10. A displacement sensor, characterized in that: The displacement sensor includes a variable capacitor, a chip for obtaining the relative position of a first capacitor plate and a second capacitor plate of the variable capacitor, and a displacement sensor control circuit as described in any one of claims 1 to 9.

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