CN209844925U - Signal amplification circuit and electronic device - Google Patents
Signal amplification circuit and electronic device Download PDFInfo
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- CN209844925U CN209844925U CN201920821881.1U CN201920821881U CN209844925U CN 209844925 U CN209844925 U CN 209844925U CN 201920821881 U CN201920821881 U CN 201920821881U CN 209844925 U CN209844925 U CN 209844925U
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Abstract
A signal amplification circuit, comprising: the device comprises an amplifying module, a first control module and a second control module, wherein the amplifying module is used for amplifying a sensing signal of an air pressure sensor and outputting a first amplified signal, and the amplifying module has a preset gain; the gain controllable module is electrically connected to the amplifying module and is used for amplifying the first amplified signal and outputting a second amplified signal; the control unit is electrically connected with the gain controllable module and used for detecting the second amplified signal and comparing the second amplified signal with a preset signal value to generate a control signal; the gain controllable module is further configured to perform gain adjustment according to the control signal. The utility model also provides an electron device. The signal amplifying circuit and the electronic device can amplify the signal of the air pressure sensor to a reasonable range, and reduce signal distortion to the maximum extent.
Description
Technical Field
The utility model relates to the field of electronic technology, especially, relate to a signal amplification circuit and contain this signal amplification circuit's electron device for carrying out enlargies to air pressure sensor's sensing signal.
Background
The air pressure sensor can produce certain degree of electric signal output after sensing the information of measurationing, and this electric signal is weak, need can be detected by back-end circuit after amplifier circuit enlargies, but if the too big signal distortion that causes of magnification easily. The existing method generally adopts an Automatic Gain Control (AGC) circuit to realize self-gain adjustment and amplification, but because the voltage of an electric signal output by an air pressure sensor is extremely small, the requirement of a rated input voltage of the AGC circuit can not be met, a resonance curve of a controlled amplification stage is easy to deform, and signal distortion is caused.
SUMMERY OF THE UTILITY MODEL
In view of the above, it is desirable to provide a signal amplifying circuit and an electronic device, which can amplify the signal of the air pressure sensor to a reasonable range and reduce the signal distortion to the maximum.
An embodiment of the utility model provides a signal amplification circuit for the sensing signal to air pressure sensor amplifies, include:
the device comprises an amplifying module, a first control module and a second control module, wherein the amplifying module is used for amplifying a sensing signal of an air pressure sensor and outputting a first amplified signal, and the amplifying module has a preset gain;
the gain controllable module is electrically connected to the amplifying module and is used for amplifying the first amplified signal and outputting a second amplified signal; and
the control unit is electrically connected with the gain controllable module and used for detecting the second amplified signal and comparing the second amplified signal with a preset signal value to generate a control signal;
the gain controllable module is further configured to perform gain adjustment according to the control signal.
Preferably, the sensing signal of the air pressure sensor is an alternating current signal, the signal amplification circuit further includes a bias processing module electrically connected to the amplification module, and the sensing signal of the air pressure sensor is subjected to voltage bias processing by the bias processing module and then output to the amplification module.
Preferably, the bias processing module includes:
a first capacitor, one end of which is used for receiving the sensing signal of the air pressure sensor;
one end of the transient suppression diode is electrically connected to one end of the first capacitor, and the other end of the transient suppression diode is grounded;
one end of the first resistor is electrically connected to the other end of the first capacitor, and the other end of the first resistor is electrically connected to a power supply end; and
and one end of the second resistor is electrically connected to the common end of the first resistor and the first capacitor, and the other end of the second resistor is grounded.
Preferably, the amplifying module includes a first amplifying unit and a second amplifying unit, the first amplifying unit is configured to amplify a first preset gain, the second amplifying unit is configured to amplify a second preset gain, and the second preset gain is greater than the first preset gain.
Preferably, the first amplification unit includes:
a first amplifier having a positive input for receiving the sensing signal; and
a third resistor electrically connected between the negative input terminal of the first amplifier and the output terminal of the first amplifier;
the second amplification unit includes:
a second capacitor, one end of which is electrically connected to the output end of the first amplifier;
one end of the fourth resistor is electrically connected to the other end of the second capacitor;
a positive input end of the second amplifier is electrically connected to one end of a fifth resistor and one end of a sixth resistor, a negative input end of the second amplifier is electrically connected to the other end of the fourth resistor, the other end of the fifth resistor is connected to a power supply end, and the other end of the sixth resistor is grounded; and
and the seventh resistor is electrically connected between the negative input end of the second amplifier and the output end of the second amplifier.
Preferably, the gain controllable module comprises:
one end of the third capacitor is electrically connected to the amplifying module;
an eighth resistor, one end of which is electrically connected to the other end of the third capacitor;
a positive input end of the third amplifier is electrically connected to one end of the eighth resistor, a negative input end of the third amplifier is electrically connected to one end of the ninth resistor and one end of the tenth resistor, the other end of the ninth resistor is electrically connected to the other end of the eighth resistor, and the other end of the tenth resistor is grounded;
the analog switch chip comprises first to eighth input ends, an output end and first to third control ends, wherein the output end of the analog switch chip is electrically connected with the output end of the third amplifier and a detection pin of the control unit, the first to third control ends of the analog switch chip are electrically connected with a control pin of the control unit, the first to eighth input ends of the analog switch chip are respectively electrically connected with one end of a feedback resistor, the other end of each feedback resistor is electrically connected with a positive input end of the third amplifier, and each feedback resistor has different resistance values.
Preferably, the signal amplification circuit further includes a level conversion module electrically connected to the control pin of the control unit and the first to third control terminals of the analog switch chip, and the level conversion module is configured to perform level conversion on the control signal output by the control pin so as to convert the control signal of the first level output by the control pin into the control signal of the second level to the first to third control terminals of the analog switch chip, where the second level is greater than the first level.
Preferably, the signal amplification circuit further includes an analog-to-digital conversion module, an input end of the analog-to-digital conversion module is electrically connected to an output end of the analog switch chip and an output end of the third amplifier, an output end of the analog-to-digital conversion module is electrically connected to a detection pin of the control unit, and the analog-to-digital conversion module is configured to perform analog-to-digital conversion on a level signal at the output end of the third amplifier to output a digital signal to the detection pin of the control unit.
Preferably, the signal amplification circuit further comprises an impedance transformation module and a voltage division module electrically connected to the gain controllable module; the impedance transformation module comprises a voltage follower and is used for carrying out impedance transformation processing on the second amplified signal output by the gain controllable module; the control unit is used for sampling the second amplified signal after the voltage division processing so as to detect a sensing signal of the air pressure sensor.
An embodiment of the present invention further provides an electronic device, which includes the signal amplifying circuit.
Compared with the prior art, the signal amplification circuit and the electronic device amplify the sensing signal of the air pressure sensor by matching an amplification module with fixed gain with an AGC (automatic gain control) amplification module, realize that the sensing signal is amplified to a measurement range firstly and then gain control is carried out, the amplification module with fixed gain can amplify a weak sensing signal to the measurement range of the AGC amplification module firstly, so that the input voltage of the AGC amplification module meets the requirement of rated input voltage, and simultaneously, the gain of the AGC amplification module is automatically adjusted by a control chip, so that the signal of the air pressure sensor is always in a reasonable amplitude range after being amplified, and the signal distortion is reduced to the maximum extent.
Drawings
Fig. 1 is a functional block diagram of an electronic device according to an embodiment of the present invention.
Fig. 2 is a functional block diagram of a signal amplification circuit according to another embodiment of the present invention.
Fig. 3A and 3B are circuit diagrams of a signal amplification circuit according to an embodiment of the present invention.
Fig. 4 is a circuit diagram of a level shift unit according to an embodiment of the present invention.
Description of the main elements
Detailed Description
The following detailed description of the invention will be further described in conjunction with the above-identified drawings.
Referring to fig. 1, an electronic device 1 is provided for an embodiment of the present invention. The electronic device 1 includes a signal amplification circuit 100 and an air pressure sensor 200. The signal amplification circuit 100 may be used to amplify the sensing signal output by the air pressure sensor 200 to a reasonable amplitude range, so that the back-end circuit may read the sensing signal, and signal distortion may be reduced to the greatest extent.
In one embodiment, the air pressure sensor 200 generates and outputs an electrical signal after detecting the pressure change, the electrical signal has a weak strength and needs to be amplified by the amplifying circuit before being detected by the back-end circuit, but if the amplification factor is too large, the signal is easily distorted non-linearly. The signal amplification circuit 100 can amplify the signal of the air pressure sensor 200 to a reasonable range, and can realize gain self-control.
The signal amplifying circuit 100 includes an amplifying module 10, a gain controllable module 20, and a control unit 30. When the air pressure sensor 200 senses the change of the air pressure, it generates and outputs a sensing signal, which is weak and can be better detected by the back-end circuit after being amplified by the signal amplifying circuit 100.
The amplifying module 10 is configured to amplify the sensing signal output by the air pressure sensor 200 and output a first amplified signal, where the amplifying module 10 has a predetermined gain. The gain controllable module 20 is electrically connected to the amplifying module 10, and the gain controllable module 20 is configured to amplify the first amplified signal and output a second amplified signal. The control unit 30 is electrically connected to the gain controllable module 20, and the control unit 30 is configured to detect the second amplified signal and compare the second amplified signal with a preset signal value to generate a control signal. The gain controllable module 20 is further configured to perform gain adjustment according to the control signal, so that the output second amplified signal is within a preset amplitude range, and signal distortion is reduced to the greatest extent.
The signal amplification circuit 100 amplifies the sensing signal output by the air pressure sensor 200 by a fixed multiple through the amplification module 10, so that the voltage of the input signal of the gain controllable module 20 is in a reasonable range (in the measurement range of the gain controllable module 20), and then the gain of the gain controllable module 20 can be adjusted through the control unit 30 according to the difference of the signal size, so that the amplified signal is always in a reasonable amplitude range, the signal distortion is reduced to the maximum extent, and the amplified sensing signal is conveniently sampled by the rear-end circuit.
In an embodiment, the signal magnitude of the input signal of the gain controllable module 20 may be detected by the control unit 30, so as to adjust the gain of the gain controllable module 20 according to different signal magnitudes, so that the amplified signal is always within a reasonable amplitude range. For example, a smaller signal is amplified by a larger factor, and a larger signal is amplified by a smaller factor, so that the amplified signal is always within a reasonable amplitude range.
Referring to fig. 2, the sensing signal output by the air pressure sensor 200 is an ac signal. The signal amplification circuit 100 further includes a bias processing module 40 electrically connected to the amplification module 10, and the sensing signal output by the air pressure sensor 200 is subjected to voltage bias processing by the bias processing module 40 and then output to the amplification module 10 for amplification.
In one embodiment, the amplifying module 10 includes a first amplifying unit 102 and a second amplifying unit 104. The first amplifying unit 102 is configured to amplify a sensing signal by a first preset gain, the second amplifying unit 104 is electrically connected to the first amplifying unit 102, and the second amplifying unit 104 is configured to amplify the signal amplified by the first amplifying unit 102 by a second preset gain. The first preset gain and the second preset gain can be set according to actual use requirements. For example, the amplification factor of the first amplifying unit 102 is 5 times, the amplification factor of the second amplifying unit 104 is 15 times, and the second preset gain is greater than the first preset gain.
In an embodiment, the gain controllable module 20 includes a switching module 202 for switching the resistance of the feedback resistor, so as to adjust the gain of the gain controllable module 20 by changing the resistance of the feedback resistor of the gain controllable module 20.
In an embodiment, the switching module 202 may implement switching of the resistance of the feedback resistor by using an analog switch chip. The control unit 30 may be a control chip, for example, the control unit 30 may be an MCU, a single chip microcomputer, or the like. The signal amplifying circuit 100 may further include an analog-to-digital conversion module 50, a level conversion module 60, an impedance conversion module 70, and a voltage division module 80. The analog-to-digital conversion module 50 is electrically connected to the gain controllable module 20 and the control unit 30, the analog-to-digital conversion module 50 is configured to convert the detected second amplified signal into a digital signal and input the digital signal to the control unit 30, and the control unit 30 can compare the second amplified signal with a preset signal value to generate a control signal.
In an embodiment, since the pin level (typically 3.3V) of the control chip is not consistent with the pin level (typically 5V) of the analog switch chip, the level shift module 60 may control the analog switch chip by outputting a control signal from the control chip. Specifically, the level conversion module 60 is electrically connected to the control unit 30 and the gain controllable module 20, and is configured to perform level conversion on the control signal output by the control chip, so as to convert the control signal at a first level into a control signal at a second level to the analog switch chip of the gain controllable module 20, where the second level is preferably greater than the first level. For example, the level conversion module 60 converts a 3.3V control signal output by the control chip into a 5V control signal, so as to control the analog switch chip to gate.
The impedance transformation module 70 is electrically connected to the gain controllable module 20, and the impedance transformation module 70 includes a voltage follower for performing impedance transformation processing on the second amplified signal output by the gain controllable module to implement impedance matching. The impedance transformation module 70 can perform buffering and isolation functions to reduce signal distortion.
In an embodiment, since the pin level (generally 3.3V) of the control chip is not consistent with the pin level (generally 5V) of the amplifier in the gain controllable module 20, the voltage dividing module 80 may enable the control chip to normally sample the amplified sensing signal without exceeding the upper sampling limit of the control chip. Specifically, the voltage dividing module 80 is electrically connected to the impedance transforming module 70, the voltage dividing module 80 is configured to perform voltage dividing processing on the second amplified signal output by the gain controllable module 20, and the control chip may sample the second amplified signal after the voltage dividing processing, so as to detect the amplified sensing signal.
Referring to fig. 3A and 3B, a circuit diagram of a signal amplifying circuit 100 according to an embodiment of the present invention is provided.
The air pressure sensor 200 may implement power supply and sensing signal transmission through an audio interface 202, for example, the air pressure sensor 200 may be connected to the signal amplifying circuit 100 through a 3.5mm audio interface.
The bias processing module 40 includes a transient suppression diode TVS1, first to third resistors R1 to R3, and a first capacitor C1. One end of the transient suppression diode TVS1 is used for receiving the sensing signal output by the air pressure sensor 200, and the other end of the transient suppression diode TVS1 is grounded. One end of the first resistor R1 is electrically connected to one end of the transient suppression diode TVS1, and the other end of the first resistor R1 is grounded. One end of the first capacitor C1 is electrically connected to one end of the first resistor R1, the other end of the first capacitor C1 is electrically connected to one end of the second resistor R2 and one end of the third resistor R3, the other end of the second resistor R2 is electrically connected to the first power terminal Vcc1, and the other end of the third resistor R3 is grounded. The voltage of the first power source terminal Vcc1 may be set according to actual requirements. In another embodiment of the present invention, the first resistor R1 may be omitted.
The first amplifying unit 102 includes a first amplifier OP1, fourth to sixth resistors R4 to R6, a second capacitor C2 and a third capacitor C3. The positive input end of the first amplifier OP1 is electrically connected to one end of the third resistor R3, and the fourth resistor R4 is electrically connected between the negative input end and the output end of the first amplifier OP 1. One end of the second capacitor C2 is electrically connected to one end of the fourth resistor R4, the other end of the second capacitor C2 is electrically connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is electrically connected to the other end of the fourth resistor R4. One end of the sixth resistor R6 is electrically connected to one end of the fourth resistor R4, the other end of the sixth resistor R6 is electrically connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is grounded. In other embodiments of the present invention, some components of the first amplifying unit 102 may be omitted, for example, the third capacitor C3 and the sixth resistor R6 may be omitted.
The second amplifying unit 104 includes a fourth capacitor C4, seventh to eleventh resistors R7 to R11, and a second amplifier OP 2. The seventh resistor R7, the fourth capacitor C4 and the eighth resistor R8 are sequentially connected in series between the output terminal of the first amplifier OP1 and the negative input terminal of the second amplifier OP 2. The ninth resistor R9 is electrically connected between the negative input terminal and the output terminal of the second amplifier OP 2. A positive input end of the second amplifier OP2 is electrically connected to one end of the tenth resistor R10 and one end of the eleventh resistor R11, another end of the tenth resistor R10 is electrically connected to the second power source terminal Vcc2, and another end of the eleventh resistor R11 is grounded. The voltage value of the second power source terminal Vcc2 may be set according to actual requirements. In other embodiments of the present invention, some elements of the second amplifying unit 104 may be omitted, for example, the seventh resistor R7 may be omitted or the eighth resistor R8 may be omitted.
The control unit 30 includes an MCU. The gain controllable module 20 includes a fifth capacitor C5, a third amplifier OP3, twelfth to fifteenth resistors R12 to R15, an analog switch chip CD1, and first to eighth feedback resistors Rb1 to Rb 8. The twelfth resistor R12, the fifth capacitor C5 and the thirteenth resistor R13 are sequentially connected in series between the output terminal of the second amplifier OP2 and the positive input terminal of the third amplifier OP 3. The fourteenth resistor R14 is electrically connected between the positive input terminal and the negative input terminal of the third amplifier OP3, one end of the fifteenth resistor R15 is electrically connected to the negative input terminal of the third amplifier OP3, and the other end of the fifteenth resistor R15 is grounded. The analog switch chip CD1 includes first to eighth access terminals CH1 to CH8, a common terminal COM, and first to third control terminals a1, B1, and C1. The first to eighth input terminals CH1 to CH8 are electrically connected to one end of the first to eighth feedback resistors Rb1 to Rb8, respectively, and the other ends of the first to eighth feedback resistors Rb1 to Rb8 are electrically connected to the positive input terminal of the third amplifier OP 3. The common terminal COM is electrically connected to an output terminal of the third amplifier OP3, and the first to third control terminals a1, B1, and C1 are electrically connected to the MCU to receive a control signal output from the MCU. In other embodiments of the present invention, some elements of the gain controllable module 20 may be omitted, for example, the twelfth resistor R12 may be omitted or the thirteenth resistor R13 may be omitted.
In an embodiment, the gain controllable module 20 may further include a digital potentiometer electrically connected between the positive input terminal and the output terminal of the third amplifier OP3, and the MCU controls a resistance value of the digital potentiometer to adjust the gain of the gain controllable module 20.
In one embodiment, the first to eighth feedback resistors Rb 1-Rb 8 have different resistance values, i.e., the gain controllable module 20 can have eight different sets of gain stages. Eight groups of different feedback resistors are obtained by controlling different switch states of the analog switch chip CD1 through the MCU, so as to adjust the gain of the gain controllable module 20.
In an embodiment, the common terminal COM is further electrically connected to the MCU, so that the MCU can detect the second amplified signal and compare the second amplified signal with a preset signal value to generate a control signal. When it is detected that the second amplified signal is greater than the preset signal value, a control signal for decreasing the gain may be output, so that the gain controllable module 20 is switched to a smaller gain stage; when it is detected that the second amplified signal is smaller than the preset signal value, a control signal for increasing the gain may be output, so that the gain controllable module 20 is switched to a higher gain stage.
In an embodiment, the MCU is electrically connected to the common node COM through the analog-to-digital conversion module 50, a signal at an output end of the third amplifier OP3 is subjected to analog-to-digital conversion by the analog-to-digital conversion module 50 and then input to the MCU, the MCU performs an operation on the input digital signal and compares an operation result with a preset signal value, when an output value of the third amplifier OP3 is detected to be smaller than the preset signal value, the analog switch chip CD1 may be controlled to increase the gain step by step, and when an output value of the third amplifier OP3 is detected to be greater than the preset signal value, the analog switch chip CD1 may be controlled to decrease the gain step by step, so as to determine the best matching gain. The specific circuit structure of the analog-to-digital conversion module 50 may adopt an analog-to-digital conversion unit in the prior art, and is not limited herein.
In one embodiment, the MCU is further electrically connected to the first to third control terminals a1, B1 and C1 through a level shift module 60. The level conversion module 60 can convert the 3.3V control signal output by the MCU into a 5V control signal, and then control the analog switch chip CD1 to switch between different switch states by using the 5V control signal. The level shift module 60 may include three level shift units 602, and each level shift unit 602 is electrically connected between a control pin of the MCU and a control terminal a1/B1/C1 of the analog switch chip CD 1. Fig. 4 illustrates a circuit diagram of an embodiment of a level shifting unit 602. The level shifter 602 is provided with a fourth power source terminal Vcc4, and level shifting is implemented by two NPN transistors Q1, Q2 and a plurality of resistors.
In one embodiment, the first to third amplifiers OP1 to OP3 may be high precision operational amplifiers, such as LT1498CS8 chips. The analog switch chip CD1 may adopt a CD4051 chip.
In one embodiment, the impedance transformation module 70 includes a fourth amplifier OP4 and a sixteenth resistor R16. The negative input terminal of the fourth amplifier OP4 is electrically connected to the output terminal of the third amplifier OP3, and the output terminal of the fourth amplifier OP4 is electrically connected to the positive input terminal and the negative input terminal of the fourth amplifier OP 4. The sixteenth resistor R16 is electrically connected between the negative input terminal and the output terminal of the fourth amplifier OP 4.
In one embodiment, the voltage divider module 80 includes seventeenth to twentieth resistors R17 to R20. One end of the seventeenth resistor R17 is electrically connected to a third power source terminal Vcc3, the other end of the seventeenth resistor R17 is electrically connected to one end of the eighteenth resistor R18 and the output terminal of the fourth amplifier OP4, and the other end of the eighteenth resistor R18 is grounded. One end of the nineteenth resistor R19 is electrically connected to the output terminal of the fourth amplifier OP4, the other end of the nineteenth resistor R19 is electrically connected to one end of the twentieth resistor R20 and the MCU, and the other end of the twentieth resistor R20 is grounded. The MCU samples a signal at one end of the twentieth resistor R20 to realize detection of the amplified sensing signal. The voltage of the third power source terminal Vcc3 may be set according to actual requirements.
According to the signal amplification circuit and the electronic device, the sensing signal of the air pressure sensor is amplified by matching an amplification module with a fixed gain and an AGC (automatic gain control) amplification module, the sensing signal is amplified to a measurement range firstly, and then gain control is carried out.
To those skilled in the art, other changes or adjustments can be made according to the practical requirements of the present invention in combination with the practical requirements of the present invention, and these changes and adjustments should fall within the scope of the present invention.
Claims (10)
1. A signal amplification circuit for amplifying a sensing signal of an air pressure sensor, the signal amplification circuit comprising:
the amplifying module is used for amplifying a sensing signal of the air pressure sensor and outputting a first amplified signal, wherein the amplifying module has a preset gain;
the gain controllable module is electrically connected to the amplifying module and is used for amplifying the first amplified signal and outputting a second amplified signal; and
the control unit is electrically connected with the gain controllable module and used for detecting the second amplified signal and comparing the second amplified signal with a preset signal value to generate a control signal;
the gain controllable module is further configured to perform gain adjustment according to the control signal.
2. The signal amplification circuit of claim 1, wherein the sensing signal of the air pressure sensor is an ac signal, the signal amplification circuit further comprises a bias processing module electrically connected to the amplification module, and the sensing signal of the air pressure sensor is subjected to voltage bias processing by the bias processing module and then output to the amplification module.
3. The signal amplification circuit of claim 2, wherein the bias processing module comprises:
a first capacitor, one end of which is used for receiving the sensing signal of the air pressure sensor;
one end of the transient suppression diode is electrically connected to one end of the first capacitor, and the other end of the transient suppression diode is grounded;
one end of the first resistor is electrically connected to the other end of the first capacitor, and the other end of the first resistor is electrically connected to a power supply end; and
and one end of the second resistor is electrically connected to the common end of the first resistor and the first capacitor, and the other end of the second resistor is grounded.
4. The signal amplifying circuit according to claim 2, wherein the amplifying module includes a first amplifying unit and a second amplifying unit, the first amplifying unit is configured to amplify a first predetermined gain, the second amplifying unit is configured to amplify a second predetermined gain, and the second predetermined gain is greater than the first predetermined gain.
5. The signal amplification circuit of claim 4, wherein the first amplification unit comprises:
a first amplifier having a positive input for receiving the sensing signal; and
a third resistor electrically connected between the negative input terminal of the first amplifier and the output terminal of the first amplifier;
the second amplification unit includes:
a second capacitor, one end of which is electrically connected to the output end of the first amplifier;
one end of the fourth resistor is electrically connected to the other end of the second capacitor;
a positive input end of the second amplifier is electrically connected to one end of a fifth resistor and one end of a sixth resistor, a negative input end of the second amplifier is electrically connected to the other end of the fourth resistor, the other end of the fifth resistor is connected to a power supply end, and the other end of the sixth resistor is grounded; and
and the seventh resistor is electrically connected between the negative input end of the second amplifier and the output end of the second amplifier.
6. The signal amplification circuit of claim 2, wherein the gain controllable module comprises:
one end of the third capacitor is electrically connected to the amplifying module;
an eighth resistor, one end of which is electrically connected to the other end of the third capacitor;
a positive input end of the third amplifier is electrically connected to one end of the eighth resistor, a negative input end of the third amplifier is electrically connected to one end of the ninth resistor and one end of the tenth resistor, the other end of the ninth resistor is electrically connected to the other end of the eighth resistor, and the other end of the tenth resistor is grounded;
the analog switch chip comprises first to eighth input ends, an output end and first to third control ends, wherein the output end of the analog switch chip is electrically connected with the output end of the third amplifier and a detection pin of the control unit, the first to third control ends of the analog switch chip are electrically connected with a control pin of the control unit, the first to eighth input ends of the analog switch chip are respectively electrically connected with one end of a feedback resistor, the other end of each feedback resistor is electrically connected with a positive input end of the third amplifier, and each feedback resistor has different resistance values.
7. The signal amplifying circuit according to claim 6, further comprising a level shifter module electrically connected to the control pin of the control unit and the first to third control terminals of the analog switch chip, wherein the level shifter module is configured to perform level shifting on the control signal output by the control pin so as to shift the control signal output by the control pin to the first to third control terminals of the analog switch chip, and wherein the second level is greater than the first level.
8. The signal amplifying circuit according to claim 6, further comprising an analog-to-digital conversion module, wherein an input terminal of the analog-to-digital conversion module is electrically connected to the output terminal of the analog switch chip and the output terminal of the third amplifier, an output terminal of the analog-to-digital conversion module is electrically connected to the detection pin of the control unit, and the analog-to-digital conversion module is configured to perform analog-to-digital conversion on a level signal at the output terminal of the third amplifier to output a digital signal to the detection pin of the control unit.
9. The signal amplifying circuit according to claim 1, further comprising an impedance transforming module and a voltage dividing module electrically connected to the gain controllable module; the impedance transformation module comprises a voltage follower and is used for carrying out impedance transformation processing on the second amplified signal output by the gain controllable module; the control unit is used for sampling the second amplified signal after the voltage division processing so as to detect a sensing signal of the air pressure sensor.
10. An electronic device, characterized in that it comprises a signal amplification circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920821881.1U CN209844925U (en) | 2019-05-31 | 2019-05-31 | Signal amplification circuit and electronic device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920821881.1U CN209844925U (en) | 2019-05-31 | 2019-05-31 | Signal amplification circuit and electronic device |
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| CN209844925U true CN209844925U (en) | 2019-12-24 |
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| CN201920821881.1U Expired - Fee Related CN209844925U (en) | 2019-05-31 | 2019-05-31 | Signal amplification circuit and electronic device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110061711A (en) * | 2019-05-31 | 2019-07-26 | 卓尔智联(武汉)研究院有限公司 | Signal amplification circuit and electronic device |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110061711A (en) * | 2019-05-31 | 2019-07-26 | 卓尔智联(武汉)研究院有限公司 | Signal amplification circuit and electronic device |
| CN110061711B (en) * | 2019-05-31 | 2024-04-30 | 卓尔智联(武汉)研究院有限公司 | Signal amplifying circuit and electronic device |
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