CN211377990U - Sensor signal conditioning circuit - Google Patents
Sensor signal conditioning circuit Download PDFInfo
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- CN211377990U CN211377990U CN202020302302.5U CN202020302302U CN211377990U CN 211377990 U CN211377990 U CN 211377990U CN 202020302302 U CN202020302302 U CN 202020302302U CN 211377990 U CN211377990 U CN 211377990U
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Abstract
The utility model discloses a sensor signal conditioning circuit, including first charge amplification module, second charge amplification module and differential amplification module, can be voltage signal with the charge signal conversion of sensor sensing element output through first charge amplification module and second charge amplification module, can carry out differential amplification with the voltage signal of first charge amplification module and second charge amplification module output through differential amplification module, compare with prior art, can convert and amplify the charge signal of sensor sensing element output, improve the interference killing feature, make things convenient for back level acquisition circuit to gather.
Description
Technical Field
The utility model relates to a monitoring facilities technical field, in particular to sensor signal conditioning circuit.
Background
The sensor is used as a monitoring device and widely applied to the fields of machinery, ships, rail transit and the like, a circuit board is arranged in a sensor shell, and physical quantities such as vibration, impact, temperature signals and the like of a measured position are sensed and converted into electric signals through a sensing element on the circuit board. The piezoelectric vibration impact sensitive element can convert a sensed vibration impact physical signal into a charge signal, the size of the charge signal is generally in direct proportion to the sensed physical signal, and the piezoelectric vibration impact sensitive element has better linearity.
However, the charge signals output by the vibration shock sensitive elements are weak and are easily interfered. Therefore, how to convert and process the charge signal output by the vibration impact sensitive element so as to be collected by a later-stage collecting circuit is a technical problem to be solved by those skilled in the art.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the utility model provides a sensor signal conditioning circuit can change and enlarge the charge signal of sensor sensing element output, improves the interference killing feature, makes things convenient for the acquisition of back level acquisition circuit.
The utility model provides a sensor signal conditioning circuit, which comprises a first charge amplification module, a second charge amplification module and a differential amplification module;
the input end of the first charge amplification module and the input end of the second charge amplification module are respectively connected with two ends of a sensor sensitive element and are used for converting charge signals output by the sensor sensitive element into voltage signals;
the first input end and the second input end of the differential amplifying module are respectively connected with the output end of the first charge amplifying module and the output end of the second charge amplifying module, and the output end of the differential amplifying module is connected with the input end of a rear-stage detection system and used for differentially amplifying voltage signals output by the first charge amplifying module and the second charge amplifying module.
Preferably, the sensor signal conditioning circuit further comprises a bootstrap module and/or an anti-interference module;
the bootstrap module is used for boosting the voltage of the voltage signals output by the first charge amplification module and the second charge amplification module;
the anti-interference module is used for enhancing the anti-interference capability of the sensor sensitive element.
Preferably, the first charge amplification module comprises a first operational amplifier, a first capacitor, a first resistor and a second resistor, and the second charge amplification module comprises a second operational amplifier, a second capacitor, a third resistor and a fourth resistor;
the inverting input end of the first operational amplifier is used as the input end of the first charge amplification module, the non-inverting input end of the first operational amplifier is connected with a first reference voltage, the output end of the first operational amplifier is used as the output end of the first charge amplification module, two ends of the first capacitor are respectively connected with the inverting input end of the first operational amplifier and the output end of the first operational amplifier, the first end of the first resistor is connected with the inverting input end of the first operational amplifier, the second end of the first resistor is connected with the first end of the second resistor, and the second end of the second resistor is connected with the output end of the first operational amplifier;
the inverting input end of the second operational amplifier is used as the input end of the second charge amplification module, the non-inverting input end of the second operational amplifier is connected to the first reference voltage, the output end of the second operational amplifier is used as the output end of the second charge amplification module, two ends of the second capacitor are respectively connected with the inverting input end of the second operational amplifier and the output end of the second operational amplifier, the first end of the third resistor is connected with the inverting input end of the second operational amplifier, the second end of the third resistor is connected with the first end of the fourth resistor, and the second end of the fourth resistor is connected with the output end of the second operational amplifier.
Preferably, the differential amplification module comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a third operational amplifier;
a first end of the fifth resistor is used as a first input end of the differential amplification module, a second end of the fifth resistor is respectively connected with a first end of the sixth resistor and an inverting input end of the third operational amplifier, a second end of the sixth resistor is connected to the first reference voltage, a first end of the seventh resistor is used as a second input end of the differential amplification module, a second end of the seventh resistor is respectively connected with a first end of the eighth resistor and a non-inverting input end of the third operational amplifier, a second end of the eighth resistor is connected with an output end of the third operational amplifier, and a common end of the eighth resistor is used as an output end of the differential amplification module.
Preferably, the bootstrap module comprises a ninth resistor, a tenth resistor and a third capacitor;
the first end of the ninth resistor is connected with the connection node of the second end of the first resistor and the first end of the second resistor, the second end of the ninth resistor is connected with the first end of the third capacitor, the second end of the third capacitor is connected with the first end of the tenth resistor, and the second end of the tenth resistor is connected with the connection node of the second end of the third resistor and the first end of the fourth resistor.
Preferably, the bootstrap module comprises an eleventh resistor and a fourth capacitor;
the first end of the eleventh resistor is connected with a connection node between the second end of the first resistor and the first end of the second resistor, the second end of the eleventh resistor is connected with the first end of the fourth capacitor, and the second end of the fourth capacitor is connected with a connection node between the second end of the third resistor and the first end of the fourth resistor.
Preferably, the anti-interference module comprises a twelfth resistor, a thirteenth resistor, a fifth capacitor and a sixth capacitor;
the first end of the twelfth resistor is connected to the first end of the sensing element and the first end of the fifth capacitor, the second end of the twelfth resistor is connected to the first end of the thirteenth resistor, the second end of the thirteenth resistor is connected to the second end of the sensing element and the first end of the sixth capacitor, a common end of the twelfth resistor and the thirteenth resistor is connected to the first reference voltage, the second end of the fifth capacitor is connected to the input end of the first charge amplification module, and the second end of the sixth capacitor is connected to the input end of the second charge amplification module.
Preferably, the interference rejection module comprises a fourteenth resistor, a seventh capacitor and an eighth capacitor;
a first end of the fourteenth resistor is connected to the first end of the sensing element and the first end of the seventh capacitor, a second end of the fourteenth resistor is connected to the second end of the sensing element and the first end of the eighth capacitor, a second end of the seventh capacitor is connected to the input end of the first charge amplification module, and a second end of the eighth capacitor is connected to the input end of the second charge amplification module.
Preferably, the sensor signal conditioning circuit further comprises a voltage-to-current conversion module;
the input end of the voltage-current conversion module is connected with the output end of the differential amplification module, and the output end of the voltage-current conversion module is connected with the input end of the rear-stage detection system and used for converting the voltage signal output by the differential amplification module into a current signal.
Preferably, the voltage-current conversion module comprises a fourth operational amplifier, a fifteenth resistor, a sixteenth resistor and an NMOS transistor;
the non-inverting input end of the fourth operational amplifier is used as the input end of the voltage-current conversion module, the inverting input end of the fourth operational amplifier is respectively connected with the first end of the fifteenth resistor and the source electrode of the NMOS tube, the second end of the fifteenth resistor is connected with the ground, the output end of the fourth operational amplifier is connected with the first end of the sixteenth resistor, the second end of the sixteenth resistor is connected with the gate electrode of the NMOS tube, and the drain electrode of the NMOS tube is used as the output end of the voltage-current conversion module.
Preferably, the sensor signal conditioning circuit further comprises an output current compensation module;
the input end of the output current compensation module is connected to a second reference voltage, and the output end of the output current compensation module is connected to the inverting input end of the fourth operational amplifier, the first end of the fifteenth resistor and a connection node of the source electrode of the NMOS transistor, and is used for generating a corresponding compensation current according to the second reference voltage and inputting the compensation current into the NMOS transistor to compensate an output current signal of the NMOS transistor.
Preferably, the output current compensation module includes a seventeenth resistor, a first end of the seventeenth resistor is used as the input end of the output current compensation module, and a second end of the seventeenth resistor is used as the output end of the output current compensation module.
Preferably, the sensor signal conditioning circuit further comprises a first power supply processing module;
the input end of the first power supply processing module is connected with an input power supply, the first output end of the first power supply processing module is used for providing power supply voltage, and the second output end of the first power supply processing module is used for providing the first reference voltage.
Preferably, the first power supply processing module comprises a diode, an eighteenth resistor, a ninth capacitor, a tenth capacitor and a first voltage regulator tube;
the anode of the diode is used as the input end of the first power processing module, the cathode of the diode is respectively connected with the first end of the eighteenth resistor and the first end of the ninth capacitor, the common end of the diode is used as the first output end of the first power processing module, the second end of the eighteenth resistor is respectively connected with the first end of the tenth capacitor and the cathode of the first voltage regulator tube, the common end of the eighteenth resistor is used as the second output end of the first power processing module, and the second end of the ninth capacitor, the second end of the tenth capacitor and the anode of the first voltage regulator tube are all connected with the ground.
Preferably, the sensor signal conditioning circuit further comprises a second power supply processing module;
the input end of the second power supply processing module is connected with the second output end of the first power supply processing module, and the output end of the second power supply processing module is used for supplying power to the temperature measuring element.
Preferably, the second power supply processing module comprises a nineteenth resistor, an eleventh capacitor and a second voltage regulator tube;
and a first end of the nineteenth resistor is used as an input end of the second power supply processing module, a second end of the nineteenth resistor is respectively connected with a first end of the eleventh capacitor and a cathode of the second voltage regulator tube, a common end of the nineteenth resistor is used as an output end of the second power supply processing module, and a second end of the eleventh capacitor and an anode of the second voltage regulator tube are both connected with the ground.
Preferably, the second power supply processing module comprises a fifth operational amplifier, a twentieth resistor and a twelfth capacitor;
the non-inverting input end of the fifth operational amplifier is used as the input end of the second power supply processing module, the inverting input end of the fifth operational amplifier is respectively connected with the output end of the fifth operational amplifier and the first end of the twentieth resistor, the second end of the twentieth resistor is connected with the first end of the twelfth capacitor, the common end of the twentieth resistor is used as the output end of the second power supply processing module, and the second end of the twelfth capacitor is connected with the ground.
The utility model provides a sensor signal conditioning circuit, the charge signal who enlargies the module through first charge and second charge and convert the sensor sensing element output into voltage signal, enlarge the voltage signal that the module exported with first charge amplification module and second charge amplification module through the differential, compare with prior art, can change and enlarge the charge signal of sensor sensing element output, improve the interference killing feature, make things convenient for the back level acquisition circuit to gather.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic structural diagram of a sensor signal conditioning circuit according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of another sensor signal conditioning circuit according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another sensor signal conditioning circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of another sensor signal conditioning circuit according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of another sensor signal conditioning circuit according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a first power processing module according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a second power processing module according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of another second power processing module according to an embodiment of the present invention.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments.
It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or be indirectly disposed on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings that is solely for the purpose of facilitating the description and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be considered as limiting the present application.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, the meaning of a plurality of or a plurality of is two or more unless specifically limited otherwise.
It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for understanding and reading the contents disclosed in the specification, and are not used for limiting the conditions that the present application can implement, so the present invention has no technical significance, and any structural modification, ratio relationship change or size adjustment should still fall within the scope of the technical content disclosed in the present application without affecting the efficacy and the achievable purpose of the present application.
Referring to fig. 1 to 8, an embodiment of the present invention provides a sensor signal conditioning circuit, including a first charge amplifying module 100, a second charge amplifying module 200 and a differential amplifying module 300, wherein an input end of the first charge amplifying module 100 and an input end of the second charge amplifying module 200 are respectively connected to two ends of a sensor, for converting a charge signal output by the sensor into a voltage signal, a first input end and a second input end of the differential amplifying module 300 are respectively connected to an output end of the first charge amplifying module 100 and an output end of the second charge amplifying module 200, an output end of the differential amplifying module 300 is connected to an input end of a rear stage detection system, and is configured to differentially amplify the voltage signal output by the first charge amplifying module 100 and the second charge amplifying module 200.
The embodiment of the utility model provides an in, the charge signal that sensor vibration strikes sensing element output is all relatively weak, and receives the interference easily, enlargies module 100 and second charge through first charge and enlargies the module 200 and can carry out the integral conversion with the charge signal that sensor vibration strikes sensing element output and become voltage signal, can carry out differential amplification with the voltage signal that first charge enlargies module 100 and second charge enlargies module 200 output through differential amplification module 300. Therefore, compared with the prior art, the charge signal output by the sensor vibration impact sensitive element can be converted and amplified, the anti-interference capability of signal transmission is improved, and the acquisition of a post-stage acquisition circuit is facilitated.
Further, on the basis of the foregoing embodiments, in some optional embodiments, the sensor signal conditioning circuit further includes a bootstrap module 400 and/or an anti-interference module 500, where the bootstrap module 400 is configured to boost the voltage of the voltage signals output by the first charge amplification module 100 and the second charge amplification module 200, and the anti-interference module 500 is configured to enhance the anti-interference capability of the sensor sensitive element.
The embodiment of the present invention provides an embodiment, consider that the gain of the sensor sensitive element is too small in the low frequency range, through designing the bootstrap module 400 between the first charge amplification module 100 and the second charge amplification module 200, the voltage of the voltage signal output by the first charge amplification module 100 and the second charge amplification module 200 can be increased. The anti-interference modules 500 are designed at two ends of the sensor sensitive element, so that the anti-interference capability of the sensor sensitive element can be improved.
Specifically, on the basis of the above embodiments, in some optional embodiments of the present invention, the first charge amplifying module 100 includes a first operational amplifier, a first capacitor, a first resistor and a second resistor, and the second charge amplifying module 200 includes a second operational amplifier, a second capacitor, a third resistor and a fourth resistor;
the inverting input end of the first operational amplifier is used as the input end of the first charge amplification module 100, the non-inverting input end of the first operational amplifier is connected with a first reference voltage, the output end of the first operational amplifier is used as the output end of the first charge amplification module 100, two ends of the first capacitor are respectively connected with the inverting input end of the first operational amplifier and the output end of the first operational amplifier, the first end of the first resistor is connected with the inverting input end of the first operational amplifier, the second end of the first resistor is connected with the first end of the second resistor, and the second end of the second resistor is connected with the output end of the first operational amplifier;
the inverting input end of the second operational amplifier is used as the input end of the second charge amplification module 200, the non-inverting input end of the second operational amplifier is connected to the first reference voltage, the output end of the second operational amplifier is used as the output end of the second charge amplification module 200, two ends of the second capacitor are respectively connected to the inverting input end of the second operational amplifier and the output end of the second operational amplifier, the first end of the third resistor is connected to the inverting input end of the second operational amplifier, the second end of the third resistor is connected to the first end of the fourth resistor, and the second end of the fourth resistor is connected to the output end of the second operational amplifier.
In the embodiment of the present invention, the first charge amplification module 100 is composed of a first operational amplifier N1A, a first capacitor C1, a first resistor R1 and a second resistor R2, and the second charge amplification module 200 is composed of a second operational amplifier N1B, a second capacitor C2, a third resistor R3 and a fourth resistor R4. The non-inverting input ends of the first operational amplifier N1A and the second operational amplifier N1B are both connected to a first reference voltage VDD, the inverting input ends of the first operational amplifier N1A and the second operational amplifier N1B are respectively connected to two ends of the sensor, and the output ends of the first operational amplifier N1A and the second operational amplifier N1B are respectively connected to the first input end and the second input end of the differential amplification module 300; a first capacitor C1 and a second capacitor C2 are used for realizing charge-to-voltage conversion, wherein the first capacitor C1 is connected between the inverting input terminal of the first operational amplifier N1A and the output terminal of the first operational amplifier N1A, and the second capacitor C1 is connected between the inverting input terminal of the second operational amplifier N1B and the output terminal of the first operational amplifier N1A; the first resistor R1 and the second resistor R2 are connected in series and then are connected in parallel to two ends of the first capacitor C1, and the first resistor R1 and the second resistor R2 are used for guaranteeing normal static operation of the first operational amplifier N1A; the third resistor R3 and the fourth resistor R4 are connected in series and then connected in parallel to two ends of the second capacitor C2, so as to ensure that the second operational amplifier N1B works normally in a static state.
Further, on the basis of the above embodiments, in some alternative embodiments, the differential amplifying module 300 includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a third operational amplifier; a first end of the fifth resistor is used as a first input end of the differential amplification module 300, a second end of the fifth resistor is connected to a first end of the sixth resistor and an inverting input end of the third operational amplifier, respectively, a second end of the sixth resistor is connected to the reference voltage, a first end of the seventh resistor is used as a second input end of the differential amplification module 300, a second end of the seventh resistor is connected to a first end of the eighth resistor and a non-inverting input end of the third operational amplifier, respectively, a second end of the eighth resistor is connected to an output end of the third operational amplifier, and a common end of the eighth resistor is used as an output end of the differential amplification module 300.
In the embodiment of the present invention, the differential amplifying module 300 is composed of two sets of symmetrical fifth resistor R5, sixth resistor R6, seventh resistor R7, eighth resistor R8 and third operational amplifier N1C. A first end of the fifth resistor R5 and a first end of the seventh resistor R7 are respectively connected to the output end of the first charge amplification module 100 and the output end of the second charge amplification module 200, and a second end of the fifth resistor R5 and a second end of the seventh resistor R7 are respectively connected to the inverting input end of the third operational amplifier N1C and the non-inverting input end of the third operational amplifier N1C; a first end of the sixth resistor R6 is connected to the first reference voltage VDD, and a second end of the sixth resistor R6 is connected to a connection node between a second end of the fifth resistor R5 and the inverting input terminal of the third operational amplifier N1C; a first end of the eighth resistor R8 is connected to a connection node between a second end of the seventh resistor R7 and the non-inverting input terminal of the third operational amplifier N1C, a second end of the eighth resistor R8 is connected to the output terminal of the third operational amplifier N1C, and a common terminal of the eighth resistor R8 is connected to the input terminal of the post-detection system; the positive power supply end of the third operational amplifier N1C is connected to the power supply voltage VCC, and the ground end of the third operational amplifier N1C is grounded.
Further, on the basis of the above embodiments, in some optional embodiments, the bootstrap module 400 includes a ninth resistor, a tenth resistor, and a third capacitor; the first end of the ninth resistor is connected with the connection node of the second end of the first resistor and the first end of the second resistor, the second end of the ninth resistor is connected with the first end of the third capacitor, the second end of the third capacitor is connected with the first end of the tenth resistor, and the second end of the tenth resistor is connected with the connection node of the second end of the third resistor and the first end of the fourth resistor.
In the embodiment of the present invention, the bootstrap module 400 is composed of a ninth resistor R9, a tenth resistor R10 and a third capacitor C3. The ninth resistor R9 and the tenth resistor R10 are both current-limiting resistors, the first end of the ninth resistor R9 is connected between the first resistor R1 and the second resistor R2, and the second end of the ninth resistor R9 is connected with one end of the third capacitor C3; a first end of the tenth resistor R10 is connected between the third resistor R3 and the fourth resistor R4, and a second end of the tenth resistor R10 is connected to the other end of the third capacitor C3; the third capacitor C3 is a bootstrap capacitor, and is used to boost the voltage of the voltage signals output by the first charge amplification module 100 and the second charge amplification module 200, so as to compensate for the defect that the gain of the sensor sensing element is too small in the low frequency range.
Optionally, in another specific embodiment, the bootstrap module 400 includes an eleventh resistor and a fourth capacitor; the first end of the eleventh resistor is connected with a connection node between the second end of the first resistor and the first end of the second resistor, the second end of the eleventh resistor is connected with the first end of the fourth capacitor, and the second end of the fourth capacitor is connected with a connection node between the second end of the third resistor and the first end of the fourth resistor. In this embodiment, the bootstrap module 400 is composed of an eleventh resistor R11 and a fourth capacitor C4.
Further, on the basis of the foregoing embodiment, in a specific implementation manner, the anti-interference module 500 includes a twelfth resistor, a thirteenth resistor, a fifth capacitor, and a sixth capacitor, where a first end of the twelfth resistor is connected to the first end of the sensor sensing element and the first end of the fifth capacitor, a second end of the twelfth resistor is connected to the first end of the thirteenth resistor, a second end of the thirteenth resistor is connected to the second end of the sensor sensing element and the first end of the sixth capacitor, a common end of the twelfth resistor and the thirteenth resistor is connected to the reference voltage, a second end of the fifth capacitor is connected to the input end of the first charge amplification module 100, and a second end of the sixth capacitor is connected to the input end of the second charge amplification module 200.
In the embodiment of the present invention, the anti-interference module 500 is composed of a twelfth resistor R12, a thirteenth resistor R13, a fifth capacitor C5 and a sixth capacitor C6. The twelfth resistor R12 and the thirteenth resistor R13 are connected in series to two ends of the sensor, a common end of the twelfth resistor R12 and the thirteenth resistor R13 is connected to the first reference voltage VDD, the fifth capacitor C5 is connected in series between the first end of the sensor and the input end of the first charge amplification module 100, and the sixth capacitor C6 is connected in series between the second end of the sensor and the input end of the second charge amplification module 200, so that the anti-interference capability of the sensor can be significantly improved.
Optionally, in another specific embodiment, the anti-interference module 500 includes a fourteenth resistor, a seventh capacitor and an eighth capacitor, where a first end of the fourteenth resistor is connected to the first end of the sensor sensing element and the first end of the seventh capacitor, a second end of the fourteenth resistor is connected to the second end of the sensor sensing element and the first end of the eighth capacitor, a second end of the seventh capacitor is connected to the input end of the first charge amplification module 100, and a second end of the eighth capacitor is connected to the input end of the second charge amplification module 200. In this embodiment, the anti-jamming module 500 is composed of a fourteenth resistor R14, a seventh capacitor C7, and an eighth capacitor C8.
Further, on the basis of the above embodiments, in some optional embodiments, the sensor signal conditioning circuit further includes a voltage-to-current conversion module 600, an input end of the voltage-to-current conversion module 600 is connected to an output end of the differential amplification module 300, and an output end of the voltage-to-current conversion module 600 is connected to an input end of the post-stage detection system, and is configured to convert the voltage signal output by the differential amplification module 300 into a current signal.
The embodiment of the utility model provides an in, consider that voltage analog signal is easily disturbed when long distance transmission, consequently still designed voltage electric current conversion module 600 after differential amplification module 300, can transmit after converting the voltage signal of differential amplification module 300 output to current signal to improve signal transmission's stability.
Further, on the basis of the foregoing embodiment, in a specific implementation manner, the voltage-to-current conversion module 600 includes a fourth operational amplifier, a fifteenth resistor, a sixteenth resistor, and an NMOS transistor, wherein a non-inverting input terminal of the fourth operational amplifier serves as an input terminal of the voltage-to-current conversion module 600, an inverting input terminal of the fourth operational amplifier is respectively connected to a first terminal of the fifteenth resistor and a source of the NMOS transistor, a second terminal of the fifteenth resistor is connected to ground, an output terminal of the fourth operational amplifier is connected to a first terminal of the sixteenth resistor, a second terminal of the sixteenth resistor is connected to a gate of the NMOS transistor, and a drain of the NMOS transistor serves as an output terminal of the voltage-to-current conversion module 600.
The embodiment of the present invention provides an embodiment, the voltage-current conversion module 600 is composed of a fourth operational amplifier N1D, a fifteenth resistor R15, a sixteenth resistor R16 and an NMOS transistor T1, wherein, the non-inverting input of the fourth operational amplifier N1D is connected to the input terminal of the differential amplification module 300, the fifteenth resistor R15 is a voltage-current conversion resistor, the first end of the fifteenth resistor R15 is connected to the inverting input of the fourth operational amplifier N1D and the source of the NMOS transistor T1, the second end of the fifteenth resistor R15 is connected to ground, the sixteenth resistor R16 is a current-limiting resistor, the output terminal of the fourth operational amplifier N1D is connected to the gate of the NMOS transistor T1 through the sixteenth resistor R16, and the drain of the NMOS transistor T1 is connected to the rear-stage detection system.
In specific implementation, considering that the output current of the sensor is small, the sixteenth resistor R16 may have a small resistance value, which may even be 0, and this is equivalent to directly removing the sixteenth resistor R16, and the implementation of the present technical solution will not be affected.
Further, on the basis of the foregoing embodiments, in some optional embodiments, the sensor signal conditioning circuit further includes an output current compensation module 700, an input end of the output current compensation module 700 is connected to a second reference voltage, and an output end of the output current compensation module 700 is connected to a connection node between an inverting input end of the fourth operational amplifier, a first end of the fifteenth resistor, and a source of the NMOS transistor, and is configured to generate a corresponding compensation current according to the second reference voltage, and input the compensation current into the NMOS transistor to compensate an output current signal thereof.
Further, on the basis of the foregoing embodiment, in a specific implementation manner, the output current compensation module 700 includes a seventeenth resistor, a first end of the seventeenth resistor is used as an input end of the output current compensation module 700, and a second end of the seventeenth resistor is used as an output end of the output current compensation module 700.
The embodiment of the utility model provides an in, the first end of seventeenth resistance R17 inserts second reference voltage, and the second end of seventeenth resistance R17 is connected the inverting input of fourth operational amplifier N1D, the first end of fifteenth resistance R15 and the connected node of NMOS pipe T1's source electrode. As can be seen from the dashed short, the voltage at the inverting input terminal of the fourth operational amplifier N1D is almost equal to the input voltage at the non-inverting input terminal, and the second reference voltage is connected to the first terminal of the seventeenth resistor R17, so that the difference between the input voltage at the non-inverting input terminal of the fourth operational amplifier N1D and the second reference voltage is added to the two terminals of the seventeenth resistor R17, so that the seventeenth resistor R17 generates a corresponding compensation current, and the compensation current is input to the NMOS transistor T1, so that the output current signal can be compensated.
As a preferred embodiment of the present invention, the sensor signal conditioning circuit further includes a first power processing module 800; the input end of the first power processing module 800 is connected to an input power, the first output end of the first power processing module 800 is used for providing a power voltage, and the second output end of the first power processing module 800 is used for providing a first reference voltage.
The embodiment of the utility model provides an in, in order to guarantee sensor signal conditioning circuit's stability, consequently increased first power processing module 800 in sensor signal conditioning circuit, its input inserts external input power, and first output provides stable mains voltage for sensor signal conditioning circuit, and the second output provides stable first reference voltage for sensor signal conditioning circuit to improve first reference voltage's precision.
Specifically, in the above embodiment, the first power processing module 800 includes a diode, an eighteenth resistor, a ninth capacitor, a tenth capacitor, and a first voltage regulator; the anode of the diode is used as the input end of the first power processing module 800, the cathode of the diode is respectively connected to the first end of the eighteenth resistor and the first end of the ninth capacitor, the common end of the diode is used as the first output end of the first power processing module 800, the second end of the eighteenth resistor is respectively connected to the first end of the tenth capacitor and the cathode of the first voltage regulator tube, the common end of the diode is used as the second output end of the first power processing module 800, and the second end of the ninth capacitor, the second end of the tenth capacitor and the anode of the first voltage regulator tube are all connected to ground.
In the embodiment of the present invention, the first power processing module 800 is composed of a diode V1, an eighteenth resistor R18, a ninth capacitor C9, a tenth capacitor C10, and a first voltage regulator Z1; the diode V1 is an anti-reverse diode, and the anode of the diode V1 is connected with an external input power supply; the ninth capacitor C9 is a filter capacitor, and has a first terminal connected to the cathode of the diode V1 and a second terminal connected to ground; a connecting node between the cathode of the diode V1 and the first end of the ninth capacitor C9 outputs a power supply voltage VCC which supplies power to a positive power supply end of an operational amplifier in the sensor signal conditioning circuit; the eighteenth resistor R18 is a current-limiting resistor for limiting the maximum current flowing through the first regulator tube Z1, and has a first end connected to the connection node between the cathode of the diode V1 and the first end of the ninth capacitor C9; a tenth capacitor C10 is a filter capacitor, a first voltage regulator tube Z1 is a voltage regulator diode, the first end of the tenth capacitor C10 and the cathode of the first voltage regulator tube Z1 are both connected with the second end of an eighteenth resistor R18, and the first end of the tenth capacitor C10 and the anode of the first voltage regulator tube Z1 are both connected with the ground; the connection node of the second terminal of the eighteenth resistor R18, the first terminal of the tenth capacitor C10, and the cathode of the first regulator tube Z1 outputs the first reference voltage VDD, and provides the first reference voltage for the first charge amplification module 100, the second charge amplification module 200, the differential amplification module 300, and the like. Optionally, the sensor sensing element may also be powered by the first reference voltage VDD; when the temperature measuring element is arranged in the sensor and outputs analog signals such as a platinum resistor temperature sensitive device, the temperature measuring element outputting the analog signals can also be directly powered by the first reference voltage VDD.
Further, on the basis of the above embodiments, in some optional embodiments, the sensor signal conditioning circuit further includes a second power supply processing module 900; the input end of the second power processing module 900 is connected to the second output end of the first power processing module 800, and the output end of the second power processing module 900 is used for supplying power to the temperature measuring element.
The embodiment of the utility model provides an in, the temperature element of considering sensor internally mounted is probably digital signal output, and sensor vibration strikes sensing element and is analog signal output, in order to avoid mutual interference, has consequently still increased second power processing module 900 in sensor signal conditioning circuit, and the second output of first power processing module 800 is connected to its input, and its output is digital signal output's temperature element power supply.
Optionally, in a specific embodiment, the second power processing module 900 includes a nineteenth resistor, an eleventh capacitor, and a second voltage regulator; a first end of the nineteenth resistor is used as an input end of the second power processing module 900, a second end of the nineteenth resistor is connected to a first end of the eleventh capacitor and a cathode of the second voltage regulator tube respectively, a common end of the nineteenth resistor is used as an output end of the second power processing module 900, and a second end of the eleventh capacitor and an anode of the second voltage regulator tube are both connected with the ground.
In the embodiment of the present invention, the second power processing module 900 is composed of a nineteenth resistor R19, an eleventh capacitor C11, and a second voltage regulator tube Z2; the nineteenth resistor R19 is a current-limiting resistor for limiting the maximum current flowing through the second voltage regulator tube Z2, and the first end of the current-limiting resistor R19 is connected to the first reference voltage VDD; the eighth capacitor C8 is a filter capacitor, the second voltage regulator tube Z2 is a voltage regulator diode, the first end of the eleventh capacitor C11 and the cathode of the second voltage regulator tube Z2 are both connected with the second end of the nineteenth resistor R19, and the first end of the eleventh capacitor C11 and the anode of the second voltage regulator tube Z2 are both connected with the ground; and the connection node of the second end of the nineteenth resistor R19, the first end of the eleventh capacitor C11 and the cathode of the second voltage regulator tube Z2 is used as the output end of the second power processing module 900 and supplies power for the temperature measuring element for outputting digital signals. That is to say, in this embodiment, the first reference voltage VDD supplies power to the temperature measuring element outputting the digital signal after passing through the separate voltage stabilizing circuit, and the circuit is simple and has low cost.
Optionally, in another specific embodiment, the second power processing module 900 includes a fifth operational amplifier, a twentieth resistor, and a twelfth capacitor; the non-inverting input terminal of the fifth operational amplifier is used as the input terminal of the second power processing module 900, the inverting input terminal of the fifth operational amplifier is connected to the output terminal of the fifth operational amplifier and the first terminal of the twentieth resistor, the second terminal of the twentieth resistor is connected to the first terminal of the twelfth capacitor, the common terminal of the twelfth capacitor is used as the output terminal of the second power processing module 900, and the second terminal of the twelfth capacitor is connected to ground.
In the embodiment of the present invention, the second power processing module 900 is composed of a fifth operational amplifier N1E, a twentieth resistor R20 and a twelfth capacitor C12; the fifth operational amplifier N1E is used as a voltage follower, the non-inverting input terminal of the fifth operational amplifier is connected to the first reference voltage VDD, and the inverting input terminal of the fifth operational amplifier is shorted with the output terminal; the twentieth resistor R20 is a current-limiting resistor, and the first end of the twentieth resistor R20 is connected with the connection node of the inverting input end and the output end of the fifth operational amplifier N1E; the twelfth capacitor C12 is a filter capacitor, and has a first end connected to the second end of the twentieth resistor R20, and a second end connected to ground; the connection node between the second end of the twentieth resistor R20 and the first end of the twelfth capacitor C12 serves as the output end of the second power processing module 900, and supplies power to the temperature measuring element for outputting digital signals. That is to say, in this embodiment, the first reference voltage VDD supplies power to the temperature measuring element outputting the digital signal after passing through the voltage follower circuit, so as to implement voltage following and improve the driving capability.
Optionally, in some embodiments of the present invention, a resistor R21 is connected between the input end of the first charge amplification module 100 and the first end of the sensor sensing element, and a resistor R22 is connected between the input end of the second charge amplification module 200 and the second end of the sensor sensing element, so that the interference rejection of the input signals of the first charge amplification module 100 and the second charge amplification module 200 can be improved.
Optionally, in some embodiments of the present invention, a balancing resistor R23 and a voltage dividing circuit are connected between the non-inverting input terminal of the fourth operational amplifier N1D and the output terminal of the differential amplifying module 300. Specifically, the balancing resistor R23 is used to balance the resistance at the input of the fourth operational amplifier N1D, perform impedance matching, and reduce offset current. The voltage divider circuit may include the resistor R24 alone, or may include the resistor R24 and the resistor R25, and divides the voltage signal output by the differential amplifier module 300 and inputs the divided voltage signal to the non-inverting input terminal of the fourth operational amplifier N1D.
Optionally, in some embodiments of the present invention, the input end of the first power processing module 800 is connected to an electrostatic discharge tube ESD1 for performing electrostatic protection on the power input interface; the output end of the temperature measuring element is connected with an electrostatic discharge tube ESD2 for carrying out electrostatic protection on the output interface of the temperature measuring element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (17)
1. A sensor signal conditioning circuit is characterized by comprising a first charge amplification module, a second charge amplification module and a differential amplification module;
the input end of the first charge amplification module and the input end of the second charge amplification module are respectively connected with two ends of a sensor sensitive element and are used for converting charge signals output by the sensor sensitive element into voltage signals;
the first input end and the second input end of the differential amplifying module are respectively connected with the output end of the first charge amplifying module and the output end of the second charge amplifying module, and the output end of the differential amplifying module is connected with the input end of a rear-stage detection system and used for differentially amplifying voltage signals output by the first charge amplifying module and the second charge amplifying module.
2. The sensor signal conditioning circuit of claim 1, further comprising a bootstrap module and/or an anti-jamming module;
the bootstrap module is used for boosting the voltage of the voltage signals output by the first charge amplification module and the second charge amplification module;
the anti-interference module is used for enhancing the anti-interference capability of the sensor sensitive element.
3. The sensor signal conditioning circuit of claim 2, wherein the first charge amplification module comprises a first operational amplifier, a first capacitor, a first resistor, and a second resistor, and the second charge amplification module comprises a second operational amplifier, a second capacitor, a third resistor, and a fourth resistor;
the inverting input end of the first operational amplifier is used as the input end of the first charge amplification module, the non-inverting input end of the first operational amplifier is connected with a first reference voltage, the output end of the first operational amplifier is used as the output end of the first charge amplification module, two ends of the first capacitor are respectively connected with the inverting input end of the first operational amplifier and the output end of the first operational amplifier, the first end of the first resistor is connected with the inverting input end of the first operational amplifier, the second end of the first resistor is connected with the first end of the second resistor, and the second end of the second resistor is connected with the output end of the first operational amplifier;
the inverting input end of the second operational amplifier is used as the input end of the second charge amplification module, the non-inverting input end of the second operational amplifier is connected to the first reference voltage, the output end of the second operational amplifier is used as the output end of the second charge amplification module, two ends of the second capacitor are respectively connected with the inverting input end of the second operational amplifier and the output end of the second operational amplifier, the first end of the third resistor is connected with the inverting input end of the second operational amplifier, the second end of the third resistor is connected with the first end of the fourth resistor, and the second end of the fourth resistor is connected with the output end of the second operational amplifier.
4. The sensor signal conditioning circuit of claim 3, wherein the differential amplification module comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a third operational amplifier;
a first end of the fifth resistor is used as a first input end of the differential amplification module, a second end of the fifth resistor is respectively connected with a first end of the sixth resistor and an inverting input end of the third operational amplifier, a second end of the sixth resistor is connected to the first reference voltage, a first end of the seventh resistor is used as a second input end of the differential amplification module, a second end of the seventh resistor is respectively connected with a first end of the eighth resistor and a non-inverting input end of the third operational amplifier, a second end of the eighth resistor is connected with an output end of the third operational amplifier, and a common end of the eighth resistor is used as an output end of the differential amplification module.
5. The sensor signal conditioning circuit of claim 4, wherein the bootstrap module includes a ninth resistor, a tenth resistor, and a third capacitor;
the first end of the ninth resistor is connected with the connection node of the second end of the first resistor and the first end of the second resistor, the second end of the ninth resistor is connected with the first end of the third capacitor, the second end of the third capacitor is connected with the first end of the tenth resistor, and the second end of the tenth resistor is connected with the connection node of the second end of the third resistor and the first end of the fourth resistor.
6. The sensor signal conditioning circuit of claim 4, wherein the bootstrap module includes an eleventh resistor and a fourth capacitor;
the first end of the eleventh resistor is connected with a connection node between the second end of the first resistor and the first end of the second resistor, the second end of the eleventh resistor is connected with the first end of the fourth capacitor, and the second end of the fourth capacitor is connected with a connection node between the second end of the third resistor and the first end of the fourth resistor.
7. The sensor signal conditioning circuit of claim 4, wherein the immunity module includes a twelfth resistor, a thirteenth resistor, a fifth capacitor, and a sixth capacitor;
the first end of the twelfth resistor is connected to the first end of the sensing element and the first end of the fifth capacitor, the second end of the twelfth resistor is connected to the first end of the thirteenth resistor, the second end of the thirteenth resistor is connected to the second end of the sensing element and the first end of the sixth capacitor, a common end of the twelfth resistor and the thirteenth resistor is connected to the first reference voltage, the second end of the fifth capacitor is connected to the input end of the first charge amplification module, and the second end of the sixth capacitor is connected to the input end of the second charge amplification module.
8. The sensor signal conditioning circuit of claim 4, wherein the immunity module includes a fourteenth resistor, a seventh capacitor, and an eighth capacitor;
a first end of the fourteenth resistor is connected to the first end of the sensing element and the first end of the seventh capacitor, a second end of the fourteenth resistor is connected to the second end of the sensing element and the first end of the eighth capacitor, a second end of the seventh capacitor is connected to the input end of the first charge amplification module, and a second end of the eighth capacitor is connected to the input end of the second charge amplification module.
9. The sensor signal conditioning circuit of any one of claims 1 to 8, further comprising a voltage to current conversion module;
the input end of the voltage-current conversion module is connected with the output end of the differential amplification module, and the output end of the voltage-current conversion module is connected with the input end of the rear-stage detection system and used for converting the voltage signal output by the differential amplification module into a current signal.
10. The sensor signal conditioning circuit of claim 9, wherein the voltage-to-current conversion module comprises a fourth operational amplifier, a fifteenth resistor, a sixteenth resistor, and an NMOS transistor; the non-inverting input end of the fourth operational amplifier is used as the input end of the voltage-current conversion module, the inverting input end of the fourth operational amplifier is respectively connected with the first end of the fifteenth resistor and the source electrode of the NMOS tube, the second end of the fifteenth resistor is connected with the ground, the output end of the fourth operational amplifier is connected with the first end of the sixteenth resistor, the second end of the sixteenth resistor is connected with the gate electrode of the NMOS tube, and the drain electrode of the NMOS tube is used as the output end of the voltage-current conversion module.
11. The sensor signal conditioning circuit of claim 10, further comprising an output current compensation module;
the input end of the output current compensation module is connected to a second reference voltage, and the output end of the output current compensation module is connected to the inverting input end of the fourth operational amplifier, the first end of the fifteenth resistor and a connection node of the source electrode of the NMOS transistor, and is used for generating a corresponding compensation current according to the second reference voltage and inputting the compensation current into the NMOS transistor to compensate an output current signal of the NMOS transistor.
12. The sensor signal conditioning circuit of claim 11, wherein the output current compensation module comprises a seventeenth resistor, a first end of the seventeenth resistor being an input end of the output current compensation module, and a second end of the seventeenth resistor being an output end of the output current compensation module.
13. The sensor signal conditioning circuit of claim 4, further comprising a first power processing module;
the input end of the first power supply processing module is connected with an input power supply, the first output end of the first power supply processing module is used for providing power supply voltage, and the second output end of the first power supply processing module is used for providing the first reference voltage.
14. The sensor signal conditioning circuit of claim 13, wherein the first power processing module comprises a diode, an eighteenth resistor, a ninth capacitor, a tenth capacitor, and a first voltage regulator;
the anode of the diode is used as the input end of the first power processing module, the cathode of the diode is respectively connected with the first end of the eighteenth resistor and the first end of the ninth capacitor, the common end of the diode is used as the first output end of the first power processing module, the second end of the eighteenth resistor is respectively connected with the first end of the tenth capacitor and the cathode of the first voltage regulator tube, the common end of the eighteenth resistor is used as the second output end of the first power processing module, and the second end of the ninth capacitor, the second end of the tenth capacitor and the anode of the first voltage regulator tube are all connected with the ground.
15. The sensor signal conditioning circuit of claim 14, further comprising a second power processing module;
the input end of the second power supply processing module is connected with the second output end of the first power supply processing module, and the output end of the second power supply processing module is used for supplying power to the temperature measuring element.
16. The sensor signal conditioning circuit of claim 15, wherein the second power processing module comprises a nineteenth resistor, an eleventh capacitor, and a second voltage regulator;
and a first end of the nineteenth resistor is used as an input end of the second power supply processing module, a second end of the nineteenth resistor is respectively connected with a first end of the eleventh capacitor and a cathode of the second voltage regulator tube, a common end of the nineteenth resistor is used as an output end of the second power supply processing module, and a second end of the eleventh capacitor and an anode of the second voltage regulator tube are both connected with the ground.
17. The sensor signal conditioning circuit of claim 15, wherein the second power processing module comprises a fifth operational amplifier, a twentieth resistor, and a twelfth capacitor;
the non-inverting input end of the fifth operational amplifier is used as the input end of the second power supply processing module, the inverting input end of the fifth operational amplifier is respectively connected with the output end of the fifth operational amplifier and the first end of the twentieth resistor, the second end of the twentieth resistor is connected with the first end of the twelfth capacitor, the common end of the twentieth resistor is used as the output end of the second power supply processing module, and the second end of the twelfth capacitor is connected with the ground.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113225036A (en) * | 2021-05-12 | 2021-08-06 | 上海电气集团股份有限公司 | Preamplifier and medical piezoelectric film sensor |
| CN113514173A (en) * | 2021-03-23 | 2021-10-19 | 武汉飞恩微电子有限公司 | Anti-interference circuit based on pressure sensor, control method and pressure sensor |
-
2020
- 2020-03-12 CN CN202020302302.5U patent/CN211377990U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113514173A (en) * | 2021-03-23 | 2021-10-19 | 武汉飞恩微电子有限公司 | Anti-interference circuit based on pressure sensor, control method and pressure sensor |
| CN113225036A (en) * | 2021-05-12 | 2021-08-06 | 上海电气集团股份有限公司 | Preamplifier and medical piezoelectric film sensor |
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