A circuit for improving the sampling accuracy of a position sensor

Abstract

The application discloses a circuit for improving sampling precision of a position sensor, comprising a reference voltage module, a sensor interface module, a filter module, a first-stage amplification module and a second-stage amplification module; the reference voltage module is connected with the sensor interface module and is used for providing a reference voltage to the interface module; the filter module is connected with the sensor interface module and is used for selecting input signal voltage of the interface module according to frequency, avoiding interference of high-frequency signals and stabilizing voltage of the circuit; the first-stage amplification module is connected with the filter module and is used for primary amplification of the voltage transmitted by the filter module; and the second-stage amplification module is connected with the first-stage amplification module and is used for secondary amplification of the voltage transmitted by the first-stage amplification module. The circuit can not only greatly improve sampling precision of the position sensor, but also can be applied in many circuits by changing parameters of resistor devices, and has high universality.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and more specifically, to a circuit for improving the sampling accuracy of a position sensor. Background Technology

[0002] A position sensor is a sensor that can detect the position of a measured object and convert it into a usable output signal. Position sensors are widely used in a variety of industrial and commercial applications, from high-end military and defense applications to low-cost automotive and home appliances.

[0003] Traditional methods for improving the sampling accuracy of position sensors involve using operational amplifiers to form a non-inverting amplifier circuit. This circuit adjusts the input signal voltage range to match the voltage detection range of the microcontroller, ensuring the voltage detection range aligns with the maximum signal voltage amplitude. However, this approach, which only uses a non-inverting amplifier circuit, increases both the lower and upper limits of the input signal voltage, wasting the low-voltage portion of the voltage detection range, and the improvement in sampling accuracy is not significant.

[0004] The circuit scheme in this invention can select the input signal voltage range to be amplified, distinguish it from the median value, increase the upper limit value while decreasing the lower limit value, make full use of the low voltage part in the voltage detection range of the microcontroller, and greatly improve the sampling accuracy of the position sensor. Summary of the Invention

[0005] This invention provides a circuit to improve the sampling accuracy of a position sensor, thereby solving the problems of low sampling accuracy and wasted voltage detection range in traditional position sensors.

[0006] This invention provides a circuit for improving the sampling accuracy of a position sensor, comprising: a reference voltage module, a sensor interface module, a filtering module, a first-stage amplification module, and a second-stage amplification module;

[0007] The reference voltage module is connected to the sensor interface module. The reference voltage module is used to provide a reference voltage to the sensor interface module and isolates the power supply circuit from the sensor interface module to eliminate mutual interference.

[0008] The filtering module is connected to the sensor interface module. The filtering module is used to select the input signal voltage of the sensor interface module according to the frequency to avoid interference from high-frequency signals and stabilize the voltage of the circuit.

[0009] The first-stage amplification module is connected to the filter module, and the first-stage amplification module is used to amplify the voltage output from the filter module.

[0010] The secondary amplification module is connected to the primary amplification module, and the secondary amplification module is used to further amplify the voltage output from the primary amplification module.

[0011] Optionally, the reference voltage module includes: resistor R1, resistor R2, operational amplifier U1, and DC power supply;

[0012] The positive signal input terminal of operational amplifier U1 is connected to one end of resistor R1 and resistor R2 respectively. The negative signal input terminal of operational amplifier U1 is connected to the signal output terminal of operational amplifier U1. The positive power supply terminal of operational amplifier U1 is connected to the power supply voltage, and the negative power supply terminal of operational amplifier U1 is grounded. The other end of resistor R1 is connected to the DC power supply. The other end of resistor R2 is grounded.

[0013] Optionally, the sensor interface module includes: a resistive position sensor J1 and a resistor R3;

[0014] One end of resistor R3 serves as detection point X1 and is connected to one pin of resistive position sensor J1, while the other end of resistor R3 is grounded. The other pin of resistive position sensor J1 is connected to the signal output terminal and the negative signal input terminal of operational amplifier U1.

[0015] Optionally, the filtering module includes: resistor R4, capacitor C1, and Zener diode D1;

[0016] One end of resistor R4 is connected to detection point X1; the negative terminal of Zener diode D1 serves as detection point X2, and is connected to the other end of resistor R4 and one end of capacitor C1 respectively. The positive terminal of Zener diode D1 is grounded; the other end of capacitor C1 is grounded.

[0017] Optionally, the first-stage amplification module includes: operational amplifier U2, resistor R5, and resistor R6;

[0018] The positive signal input terminal of operational amplifier U2 is connected to detection point X2, and the negative signal input terminal of operational amplifier U2 is connected to one end of resistor R5 and one end of resistor R6 respectively; the signal output terminal of operational amplifier U2 serves as detection point X3 and is connected to the other end of resistor R6; the positive power supply terminal of operational amplifier U2 is connected to the power supply voltage, and the negative power supply terminal of operational amplifier U2 is grounded; the other end of resistor R5 is grounded.

[0019] Optionally, the secondary amplification module includes: operational amplifier U3, resistor R7, resistor R8, and resistor R9;

[0020] The positive signal input terminal of operational amplifier U3 is connected to detection point X3. The negative signal input terminal of operational amplifier U3 is connected to one end of resistor R7, one end of resistor R8, and one end of resistor R9, respectively. The signal output terminal of operational amplifier U3 is connected to the other end of resistor R9. The positive power supply terminal of operational amplifier U3 is connected to the power supply voltage, and the negative power supply terminal of operational amplifier U3 is grounded. The other end of resistor R7 is connected to the power supply voltage, and the other end of resistor R8 is grounded.

[0021] Optionally, by inputting a signal from detection point X1 and measuring the output signal of detection point X2 using an oscilloscope, it is possible to detect whether the filter module is working properly; by comparing the voltages at detection point X2 and detection point X3, it is possible to detect whether the first-stage amplification module is working properly; and by comparing the voltage at detection point X3 with the voltage at the signal output terminal of operational amplifier U3, it is possible to detect whether the second-stage amplification module is working properly.

[0022] Optionally, the voltage amplification ratio can be changed by adjusting the resistance values ​​of resistors R5 and R6 in the first-stage amplification module; the median voltage output by the first-stage amplification module is half that of the DC power supply; the voltage after first-stage amplification is:

[0023]

[0024] In the formula, "V" i "V1" represents the output voltage of the first-stage amplifier module, "V2" represents the input voltage of the first-stage amplifier module, R5 represents the resistance value of resistor R5, and R6 represents the resistance value of resistor R6.

[0025] Optionally, the voltage amplification ratio can be changed by adjusting the resistance values ​​of resistors R7, R8, and R9 in the secondary amplification module; the voltage after secondary amplification is:

[0026]

[0027] In the formula, "V" o "V" represents the output voltage of the secondary amplifier module. i "r1" represents the voltage output of the first-stage amplifier module, "r2" represents the resistance values ​​of resistors R7 and R8, and "r3" represents the resistance value of resistor R9.

[0028] Optionally, the resistors R7 and R8 in the secondary amplification module have the same resistance value.

[0029] The present invention has at least the following beneficial effects:

[0030] 1. This invention makes full use of the low voltage portion of the voltage detection range. Compared with traditional sampling accuracy amplifier circuits, it can not only increase the upper limit of the measured voltage, but also reduce the lower limit of the measured voltage, thus matching the voltage detection range to the greatest extent and significantly improving the sampling accuracy of the position sensor.

[0031] 2. The circuit of the present invention can easily adjust the amplification ratio of the sampling voltage and set the factor for improving the sampling accuracy by changing the parameters of the resistive device. It has high versatility and can therefore be applied in many circuits. Attached Figure Description

[0032] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0033] Figure 1 This is a circuit schematic diagram of a specific embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, this invention provides a circuit for improving the sampling accuracy of a position sensor, comprising: a reference voltage module, a sensor interface module, a filtering module, a first-stage amplification module, and a second-stage amplification module; the reference voltage module is connected to the sensor interface module and is used to provide a reference voltage to the sensor interface module, and to isolate the power supply circuit and the sensor interface module to eliminate mutual interference; the filtering module is connected to the sensor interface module and is used to select the input signal voltage of the sensor interface module according to frequency, to avoid interference from high-frequency signals, and to stabilize the voltage of the circuit; the first-stage amplification module is connected to the filtering module and is used to amplify the voltage output from the filtering module initially; the second-stage amplification module is connected to the first-stage amplification module and is used to amplify the voltage output from the first-stage amplification module further.

[0036] The reference voltage module includes: resistor R1, resistor R2, and operational amplifier U1; the positive signal input terminal of operational amplifier U1 is connected to one end of resistor R1 and resistor R2, the negative signal input terminal of operational amplifier U1 is connected to the signal output terminal of operational amplifier U1, the positive power supply terminal of operational amplifier U1 is connected to the power supply voltage, and the negative power supply terminal of operational amplifier U1 is grounded; the other end of resistor R1 is connected to the power supply voltage; and the other end of resistor R2 is grounded.

[0037] The sensor interface module includes: a resistive position sensor J1 and a resistor R3; the resistive position sensor J1 includes pins 1 and 2; one end of the resistor R3 serves as the detection point X1 and is connected to pin 2 of the resistive position sensor J1; the other end of the resistor R3 is grounded. Pin 1 of the resistive position sensor J1 is connected to the signal output terminal and the negative signal input terminal of the operational amplifier U1 of the reference voltage module.

[0038] The filtering module includes: resistor R4, capacitor C1, and Zener diode D1; one end of resistor R4 is connected to detection point X1; the negative terminal of Zener diode D1 serves as detection point X2 and is connected to the other end of resistor R4 and one end of capacitor C1; the positive terminal of Zener diode D1 is grounded. The other end of capacitor C1 is grounded.

[0039] The first-stage amplification module includes: operational amplifier U2, resistor R5, and resistor R6; the positive signal input terminal of operational amplifier U2 is connected to detection point X2, the negative signal input terminal of operational amplifier U2 is connected to one end of resistor R5 and one end of resistor R6, the signal output terminal of operational amplifier U2 serves as detection point X3 and is connected to the other end of resistor R6, the positive power supply terminal of operational amplifier U2 is connected to the power supply voltage, the negative power supply terminal of operational amplifier U2 is grounded; the other end of resistor R5 is grounded.

[0040] The secondary amplification module includes: operational amplifier U3, resistors R7, R8, and R9; the positive signal input terminal of operational amplifier U3 is connected to detection point X3, the negative signal input terminal of operational amplifier U3 is connected to one end of resistor R7, one end of resistor R8, and one end of resistor R9, the signal output terminal of operational amplifier U3 is connected to the other end of resistor R9, the positive power supply terminal of operational amplifier U3 is connected to the power supply voltage, and the negative power supply terminal of operational amplifier U3 is grounded; the other end of resistor R7 is connected to the power supply voltage; and the other end of resistor R8 is grounded.

[0041] By comparing the signals at detection point X1 and X2 using an oscilloscope, it is possible to detect whether the filter module is working properly; by comparing the voltages at detection point X2 and X3, it is possible to detect whether the first-stage amplifier module is working properly; by comparing the voltage at detection point X3 with the voltage at the signal output terminal of operational amplifier U3, it is possible to detect whether the second-stage amplifier module is working properly.

[0042] The output voltage of the reference voltage module can be changed by adjusting the resistance values ​​of resistors R1 and R2 in the reference voltage module.

[0043]

[0044] Where, "V1" is the voltage output by the reference voltage module, "V REF "R1 is the power supply voltage, R2 is the resistance value of resistor R1, and R2 is the resistance value of resistor R2.

[0045] By adjusting the values ​​of resistors R5 and R6 in the first-stage amplifier module, the ratio of the first-stage amplifier voltage can be changed; the median voltage output by the first-stage amplifier module is the DC power supply V. REF Half of; the voltage after one stage of amplification is:

[0046]

[0047] Among them, “V” i "V1" represents the output voltage of the first-stage amplifier module, "V2" represents the input voltage of the first-stage amplifier module, R5 represents the resistance value of resistor R5, and R6 represents the resistance value of resistor R6.

[0048] By adjusting the values ​​of resistors R7, R8, and R9 in the secondary amplification module, the ratio of the secondary amplified voltage can be changed; the voltage after secondary amplification is:

[0049]

[0050] Among them, “V” o "V" represents the output voltage of the secondary amplifier module. i "r1" represents the voltage output of the first-stage amplifier module, "r2" represents the resistance values ​​of resistors R7 and R8, and "r3" represents the resistance value of resistor R9.

[0051] When the input voltage of the secondary amplifier module is equal to the DC power supply V REF When the input voltage is half of the input voltage, the output voltage of the second-stage amplifier module is equal to the input voltage, so the median of the voltage range after two-stage amplification remains unchanged; when the input voltage of the second-stage amplifier module is greater than the DC power supply V... REF When the input voltage of the secondary amplifier module is half of the DC power supply voltage, the output voltage of the secondary amplifier module is amplified proportionally; when the input voltage of the secondary amplifier module is less than the DC power supply voltage V... REF When the voltage is reduced to half its original value, the output voltage of the secondary amplifier module is proportionally reduced, thus significantly expanding the voltage detection range.

[0052] For example, when the DC power supply V REF When the input signal voltage is 3.3V, the voltage range of the input signal to be amplified, i.e., the voltage range of the second-stage amplifier module, is 1.5~1.8V. Resistors R7=R8=1kΩ and resistor R9=4.7kΩ are selected.

[0053]

[0054]

[0055]

[0056] Calculations show that the output voltage range after two-stage amplification is 0.09 to 3.21V, which expands the voltage detection range by 10.4 times.

[0057] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A circuit for improving the sampling accuracy of a position sensor, characterized by, The application relates to a sensor interface module and a sensor signal processing circuit. The sensor interface module is connected with a reference voltage module, a filter module, a first-stage amplification module and a second-stage amplification module. The reference voltage module is connected with the sensor interface module, and is used for providing a reference voltage for the sensor interface module and isolating a power supply circuit from the sensor interface module to eliminate mutual influence between the two. The filter module is connected with the sensor interface module, and is used for selecting input signal voltage of the sensor interface module according to frequency to avoid interference of high-frequency signals and stabilize voltage of the circuit. The first-stage amplification module is connected with the filter module, and is used for primary amplification of the voltage transmitted by the filter module. The second-stage amplification module is connected with the first-stage amplification module, and is used for secondary amplification of the voltage transmitted by the first-stage amplification module. The reference voltage module comprises a resistor R1, a resistor R2, an operational amplifier U1 and a direct-current power supply. The positive signal input end of the operational amplifier U1 is connected with one end of the resistor R1 and one end of the resistor R2, the negative signal input end of the operational amplifier U1 is connected with the signal output end of the operational amplifier U1, the positive power supply end of the operational amplifier U1 is connected with a power supply voltage, and the negative power supply end of the operational amplifier U1 is grounded; the other end of the resistor R1 is connected with the direct-current power supply; and the other end of the resistor R2 is grounded. The first-stage amplification module comprises the operational amplifier U2, a resistor R5 and a resistor R6. The positive signal input end of the operational amplifier U2 is connected with a detection point X2, the negative signal input end of the operational amplifier U2 is connected with one end of the resistor R5 and one end of the resistor R6, the signal output end of the operational amplifier U2 is connected with the other end of the resistor R6 as a detection point X3, the positive power supply end of the operational amplifier U2 is connected with the power supply voltage, the negative power supply end of the operational amplifier U2 is grounded, and the other end of the resistor R5 is grounded. The resistance values of the resistor R5 and the resistor R6 in the first-stage amplification module can be set to change the first-stage amplification ratio of voltage, the voltage output by the first-stage amplification module is half of the direct-current power supply, and the voltage after the first-stage amplification is: ； In the formula, Vout is the output voltage of the first amplification module, Vin is the input voltage of the first amplification module, R5 is the resistance value of the resistor R5, and R6 is the resistance value of the resistor R6. The second-stage amplification module comprises the operational amplifier U3, a resistor R7, a resistor R8 and a resistor R9. The positive signal input end of the operational amplifier U3 is connected with the detection point X3, the negative signal input end of the operational amplifier U3 is connected with one end of the resistor R7, one end of the resistor R8 and one end of the resistor R9, the signal output end of the operational amplifier U3 is connected with the other end of the resistor R9, the positive power supply end of the operational amplifier U3 is connected with the power supply voltage, the negative power supply end of the operational amplifier U3 is grounded, the other end of the resistor R7 is connected with the power supply voltage, and the other end of the resistor R8 is grounded. The resistance values of the resistor R7, the resistor R8 and the resistor R9 in the second-stage amplification module can be set to change the second-stage amplification ratio of voltage, and the voltage after the second-stage amplification is: ； In the formula, is the output voltage of the secondary amplification module, is the output voltage of the primary amplification module, is the resistance value of the resistor R7 and the resistor R8, is the resistance value of the resistor R9.

2. The circuit for improving position sensor sampling accuracy of claim 1, wherein, The sensor interface module comprises a resistor-type position sensor J1 and a resistor R3. One end of the resistor R3 is connected with one pin of the resistive position sensor J1 as the detection point X1, and the other end of the resistor R3 is grounded; the other pin of the resistive position sensor J1 is connected with the signal output end and the negative signal input end of the operational amplifier U1.

3. The circuit for improving position sensor sampling accuracy of claim 1, wherein, The filter module comprises a resistor R4 and a capacitor C1, and a stabilizing tube D1. One end of the resistor R4 is connected with the detection point X1; the negative electrode of the stabilizing tube D1 is connected with the other end of the resistor R4 and one end of the capacitor C1 as the detection point X2, and the positive electrode of the stabilizing tube D1 is grounded; and the other end of the capacitor C1 is grounded.

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