A signal conversion circuit, detection device and vehicle

Abstract

The application provides a signal conversion circuit, a detection device and a vehicle, and applies to the technical field of electronics. The signal conversion circuit comprises a conversion circuit and a comparison circuit. The conversion circuit is connected with the comparison circuit, is used for receiving a current type first pulse width modulation signal output by a current type sensor, and converts the first pulse width modulation signal into a voltage signal to output to the comparison circuit. The comparison circuit is used for outputting a high voltage level when the voltage signal is greater than a reference voltage, and outputting a low voltage level when the voltage signal is less than the reference voltage, so as to obtain a voltage type second pulse width modulation signal composed of the high voltage level and the low voltage level. The signal conversion circuit provided by the application can enable a control unit to detect a target signal through a current type sensor, so that the current type sensor can be matched with the control unit, and the use range of the current type sensor is expanded.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and more specifically, to a signal conversion circuit, a detection device, and a vehicle in the field of electronic technology. Background Technology

[0002] In the field of electronics, current-type sensors convert the target signal to be detected into a current-type pulse width modulation (PWM) signal and output it. Compared with voltage-type sensors, current-type sensors have stronger anti-interference capabilities and longer transmission distances. Under complex operating conditions, using current-type sensors can better ensure the stability and accuracy of signal acquisition.

[0003] However, in practical applications, many control units typically choose voltage-type sensors to detect target signals, so the input signal of the control unit is generally a voltage signal. Since current-type sensors output current-type PWM signals, they cannot be directly paired with existing control units. This results in current-type sensors, despite their superior performance, having a narrower application range than voltage-type sensors, which to some extent limits their applicability. Utility Model Content

[0004] This application provides a signal conversion circuit, a detection device, and a vehicle, which expands the application range of sensors that output current-type PWM signals.

[0005] In a first aspect, a signal conversion circuit is provided, the signal conversion circuit comprising: A conversion circuit, connected to a comparator circuit, is used to receive a current-type first pulse width modulation signal output by a current-type sensor, and convert the first pulse width modulation signal into a voltage signal to be output to the comparator circuit. The comparator circuit is configured to output a high-level voltage when the voltage signal is greater than the reference voltage, and to output a low-level voltage when the voltage signal is less than the reference voltage, so as to obtain a voltage-type second pulse width modulation signal composed of the high-level voltage and the low-level voltage.

[0006] This application provides a signal conversion circuit, which includes a conversion circuit and a comparator circuit. The conversion circuit is connected to the comparator circuit and is used to receive a current-type first pulse width modulation signal output by a sensor, convert the first pulse width modulation signal into a voltage signal, and output it to the comparator circuit. The comparator circuit is used to output a high-level voltage when the voltage signal is greater than a reference voltage, and to output a low-level voltage when the voltage signal is less than the reference voltage, so as to obtain a voltage-type second pulse width modulation signal composed of a high-level voltage and a low-level voltage. The signal conversion circuit provided by this application enables the control unit to detect the target signal through the current-type sensor, thereby enabling the combination of the current-type sensor and the control unit and expanding the application range of the current-type sensor.

[0007] Optionally, the signal conversion circuit further includes a follower circuit, the input terminal of which is connected to the conversion circuit, and the output terminal of which is connected to the comparator circuit, so as to connect the conversion circuit and the comparator circuit and transmit the voltage signal output by the conversion circuit to the comparator circuit.

[0008] Optionally, the follower circuit includes an operational amplifier and a first functional resistor; the non-inverting input of the operational amplifier is connected to the conversion circuit, and the output of the operational amplifier is connected to the comparator circuit; one end of the first functional resistor is connected to the inverting input of the operational amplifier, and the other end is connected to the output of the operational amplifier.

[0009] Optionally, the signal conversion circuit further includes: a first current-limiting resistor, one end of which is connected to the output terminal of the follower circuit and the other end of which is connected to the input terminal of the comparator circuit; and a first filter capacitor, one end of which is connected to the input terminal of the comparator circuit and the other end of which is grounded.

[0010] Optionally, the conversion circuit includes a plurality of second functional resistors connected in parallel, the plurality of second functional resistors having equal resistance values, one end of the plurality of second functional resistors being grounded, and the other end constituting the input terminal of the conversion circuit for receiving the first pulse width modulation signal.

[0011] Optionally, the signal conversion circuit further includes a clamping diode, one end of which is connected to the input terminal of the conversion circuit, and the other end is grounded.

[0012] Optionally, the signal conversion circuit further includes: a second current-limiting resistor, one end of which is connected to the output terminal of the conversion circuit, and the other end of which is connected to the input terminal of the follower circuit; The second filter capacitor has one end grounded and the other end connected to the input terminal of the follower circuit.

[0013] Optionally, the signal conversion circuit further includes: a third current-limiting resistor, one end of which is connected to the output terminal of the comparator circuit, and the other end of which constitutes the output terminal of the signal conversion circuit; and a third filter capacitor, one end of which is grounded, and the other end of which is connected to the output terminal of the signal conversion circuit.

[0014] In a second aspect, a detection device is provided, including a signal conversion circuit, a current-type sensor, and a control unit as described in the first aspect; The current-type sensor is connected to the signal conversion circuit and is used to output the first pulse width modulation signal and input the first pulse width modulation signal to the signal conversion circuit. The signal conversion circuit is connected to the control unit and is used to convert the first pulse width modulation signal into the second pulse width modulation signal and input the second pulse width modulation signal to the control unit.

[0015] Thirdly, a vehicle is provided that includes the detection device as described in the second aspect. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating an application scenario of a signal conversion circuit provided in an embodiment of this application; Figure 2 This is a schematic diagram of the circuit principle of a signal conversion circuit provided in an embodiment of this application; Figure 3 This is a schematic diagram of the circuit principle of another signal conversion circuit provided in an embodiment of this application; Figure 4 This is a schematic diagram of an application scenario for a detection device provided in an embodiment of this application. Detailed Implementation

[0017] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0018] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting 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.

[0019] Currently, some sensors convert the target signal to be detected into a PWM signal and output it. These sensors are mainly divided into current-type and voltage-type sensors. Current-type sensors output current-type PWM signals, and voltage-type sensors output voltage-type PWM signals. A current-type PWM signal refers to a current pulse signal that periodically switches between high and low current, while a voltage-type PWM signal refers to a voltage pulse signal that periodically switches between high and low voltage.

[0020] In practical applications, the input signal to the control unit is generally a voltage signal. Therefore, when detecting a target signal, a voltage-type sensor is usually selected to be paired with the control unit. The voltage-type sensor converts the target signal into a voltage-type PWM signal and inputs the voltage-type PWM signal to the control unit. The control unit determines the actual value of the target signal based on the voltage-type PWM signal.

[0021] Compared to voltage sensors, current sensors have stronger anti-interference capabilities and longer transmission distances. However, because current sensors cannot be paired with control units, their application range is narrower than that of voltage sensors, which limits their use to some extent.

[0022] For example, in the automotive field, it is necessary to detect the rotational speed (i.e., the target signal) of the output shaft of an automatic transmission. Since the input signal of the automatic transmission control unit (TCU) in a vehicle is usually a voltage signal, only voltage-type sensors (such as voltage-type speed sensors) can be selected to be paired with the control unit. The voltage-type speed sensor converts the rotational speed of the output shaft into a voltage-type PWM signal and outputs a voltage-type PWM signal to the control unit. The control unit determines the actual value of the rotational speed of the output shaft based on the voltage-type PWM signal.

[0023] It is understandable that, since current-type sensors have stronger anti-interference capabilities and longer transmission distances than voltage-type sensors, when a voltage-type speed sensor is selected to detect the output shaft speed, the reliability and accuracy of the final actual output shaft speed obtained are lower compared to when a current-type speed sensor is selected.

[0024] To address the incompatibility between current-type sensors and control units, this application provides a signal conversion circuit. This circuit receives a current-type PWM signal output from a current-type sensor and converts it into a voltage-type PWM signal. By configuring this signal conversion circuit for a current-type sensor, the control unit can detect target signals through the current-type sensor, thereby enabling the pairing of current-type sensors and control units and expanding the application range of current-type sensors.

[0025] Taking a vehicle as an example, when the current-type sensor is a current-type speed sensor, a signal conversion circuit can be configured for the speed sensor. The speed sensor detects the speed of the output shaft and outputs a current-type PWM signal. The signal conversion circuit converts the current-type PWM signal into a voltage-type PWM signal and outputs it to the TCU. The TCU determines the actual value of the output shaft speed based on the received voltage-type PWM signal. This allows the TCU to detect the speed of the automatic transmission's output shaft through a current-type sensor, which provides a more reliable and accurate output shaft speed compared to using a voltage-type sensor.

[0026] It should be understood that the speed sensor can detect not only the output shaft speed of the automatic transmission, but also the speed of the motor and engine. In this case, the control unit can be a microcontroller unit (MCU) or other types of control units within the vehicle.

[0027] See Figure 1 , Figure 1 This is a schematic diagram illustrating an application scenario of a signal conversion circuit provided in an embodiment of this application. For example... Figure 1 As shown, this scenario includes a sensor 10, a signal conversion circuit 20, and a control unit 30. The sensor 10 is a current-type sensor used to detect the target signal and convert it into a current-type PWM signal (hereinafter referred to as the first pulse width modulation signal). The output terminal of the sensor 10 is connected to the input terminal of the signal conversion circuit 20, and is used to output the converted first pulse width modulation signal to the signal conversion circuit 20. The output terminal of the signal conversion circuit 20 is connected to the input terminal of the control unit 30, and is used to convert the first pulse width modulation signal into a voltage-type second pulse width modulation signal, and output the second pulse width modulation signal to the control unit 30. The control unit 30 can determine the actual value of the target signal based on the second pulse width modulation signal.

[0028] Based on the above examples, the current-type sensor 10 can be a current-type speed sensor, and the control unit 30 can be a TCU or MCU in the vehicle. The current-type sensor 10 can detect the rotational speed (i.e., the target signal) of the output shaft of the automatic transmission, convert the detected speed into a current-type first pulse-width modulation (PWM) signal, and output the first PWM signal to the signal conversion circuit 20. The signal conversion circuit 20 converts the first PWM signal to a voltage-type second PWM signal and outputs the second PWM signal to the MCU or TCU. The MCU or TCU can determine the actual value of the rotational speed and the direction of rotation of the output shaft of the automatic transmission based on the frequency and duty cycle of the second PWM signal.

[0029] It should be noted that the current-type sensor 10 can be a speed sensor or other sensors that output current-type PWM signals, such as an angle sensor. The control unit 30 can be an MCU or a TCU, or other types of control units with voltage-type input terminals.

[0030] In this embodiment, the signal conversion circuit includes a conversion circuit and a comparison circuit. The conversion circuit is connected to the comparison circuit and is used to receive the current-type first pulse width modulation signal output by the current-type sensor, and convert the first pulse width modulation signal into a voltage signal for output to the comparison circuit. The comparison circuit is used to output a high-level voltage when the voltage signal is greater than a reference voltage, and to output a low-level voltage when the voltage signal is less than the reference voltage, so as to obtain a voltage-type second pulse width modulation signal composed of a high-level voltage and a low-level voltage.

[0031] See Figure 2 , Figure 2 This is a schematic diagram of the circuit principle of a signal conversion circuit provided in an embodiment of this application. The signal conversion circuit 20 includes a conversion circuit 21 and a comparison circuit 22. The conversion circuit 21 can be composed of a single resistor. One end of the resistor constitutes the input terminal of the conversion circuit 21 and also constitutes the output terminal of the conversion circuit 21. It is used to connect to the current-type sensor 10 to receive the first pulse width modulation signal A input by the current-type sensor 10. It is also used to connect to the input terminal of the comparison circuit 22 to output the converted voltage signal to the comparison circuit 22.

[0032] like Figure 2 As shown, the comparator circuit 22 can be composed of a first operational amplifier 221 and its peripheral circuitry. The peripheral circuitry includes a fourth filter capacitor 224, and a first voltage divider resistor 222 and a second voltage divider resistor 223 connected in series between the voltage terminal (5V) and the ground terminal (GND) of the signal conversion circuit. The positive voltage input terminal of the first operational amplifier 221 is connected to the voltage terminal, and the negative voltage input terminal is grounded, so that the first operational amplifier 221 is powered by the power supply voltage of the voltage terminal.

[0033] One end of the fourth filter capacitor 224 is connected to the voltage terminal, and the other end is grounded. It is used to filter the voltage at the voltage input terminal of the first operational amplifier 221 to improve the stability and reliability of the first operational amplifier 221.

[0034] The connection node between the first voltage divider resistor 222 and the second voltage divider resistor 223 is connected to the inverting input terminal of the first operational amplifier 221. The first voltage divider resistor 222 and the second voltage divider resistor 223 are used to divide the power supply voltage at the voltage terminal so as to provide a reference voltage to the inverting input terminal of the first operational amplifier 221 through the connection node between the first voltage divider resistor 222 and the second voltage divider resistor 223.

[0035] The non-inverting input of the first operational amplifier 221 forms the input of the comparator circuit 22, which is used to connect to the conversion circuit 21 to receive the voltage signal output by the conversion circuit 21. The output of the first operational amplifier 221 forms the output of the comparator circuit 22, which is used to connect to the control unit to output the converted second pulse width modulation signal B to the control unit.

[0036] Optionally, the signal conversion circuit further includes a first current-limiting resistor and a first filter capacitor. One end of the first current-limiting resistor is connected to the output terminal of the conversion circuit 21, and the other end is connected to the input terminal of the comparator circuit. One end of the first filter capacitor is connected to the input terminal of the comparator circuit, and the other end is grounded.

[0037] like Figure 2 As shown, the signal conversion circuit 20 may further include a first current-limiting resistor 23 and a first filter capacitor 24. One end of the first current-limiting resistor 23 is connected to the output terminal of the conversion circuit 21, and the other end is connected to the input terminal of the comparator circuit 22, for limiting the current of the voltage signal input to the comparator circuit 22. One end of the first filter capacitor 24 is connected to the input terminal of the comparator circuit 22, and the other end is grounded, for filtering the voltage signal input to the comparator circuit 22.

[0038] Optionally, the signal conversion circuit may further include a third current-limiting resistor and a third filter capacitor. One end of the third current-limiting resistor is connected to the output of the comparator circuit, and the other end constitutes the output of the signal conversion circuit. One end of the third filter capacitor is grounded, and the other end is connected to the output of the signal conversion circuit.

[0039] like Figure 2 As shown, the signal conversion circuit 20 may further include a third current-limiting resistor 26 and a third filter capacitor 27. One end of the third current-limiting resistor 26 is connected to the output terminal of the comparator circuit 22, and the other end forms the output terminal of the signal conversion circuit 20, which is used to connect to the control unit to limit the current of the second pulse width modulation signal input to the control unit from the signal conversion circuit 20. One end of the third filter capacitor 27 is grounded, and the other end is connected to the output terminal of the signal conversion circuit to filter the second pulse width modulation signal input to the control unit from the signal conversion circuit 20.

[0040] Optionally, the signal conversion circuit 20 may further include a pull-up resistor 25, one end of which is connected to a voltage terminal, and the other end is connected to the output terminal of the comparator circuit 22. The pull-up resistor 25 is used to output an initial high-level voltage to the control unit 30 when the current sensor 10 does not input a first pulse width modulation signal to the signal conversion circuit 20.

[0041] When the current-type sensor 10 inputs the first pulse width modulation signal to the signal conversion circuit 20, the conversion circuit 21 is used to convert the current-type first pulse width modulation signal output by the current-type sensor 10 into a periodically changing voltage signal, and the comparison circuit 22 converts the periodically changing voltage signal into a voltage-type second pulse width modulation signal, so as to input the second pulse width modulation signal to the control unit 30.

[0042] For example, suppose the low current range of the first pulse width modulation signal output by the current-type sensor 10 is 5-8 mA and the high current range is 12-16 mA. The conversion circuit 21 selects an appropriate resistor (e.g., 1.2K). When the first pulse width modulation signal A is input, the conversion circuit 21 can convert the 5-8 mA current signal into a 1.5-2.4 V voltage signal and the 12-16 mA current signal into a 3.6-4.8 V voltage signal. This allows the periodically changing voltage signal to be input to the comparator circuit 22. This voltage signal is then current-limited by the first current-limiting resistor 23 and filtered by the first filter capacitor 24 before being input to the comparator circuit 22.

[0043] Simultaneously, the first voltage divider resistor 222 and the second voltage divider resistor 223 are selected with appropriate resistors so that the first voltage divider resistor 222 and the second voltage divider resistor 223 can provide a 3V reference voltage to the inverting input terminal of the first operational amplifier 221. When a voltage signal of 1.5-2.4V is input to the comparator circuit 22, the comparator circuit 22 can output a low-level voltage of 0V. When a voltage signal of 3.6-4.8V is input to the comparator circuit 22, the comparator circuit 22 can output a high-level voltage of 3V. The periodically changing low-level voltage and high-level voltage constitute the second pulse width modulation signal. The second pulse width modulation signal is input to the control unit 30 after being current-limited by the third current-limiting resistor 26 and filtered by the third filter capacitor 27.

[0044] During this process, the first current-limiting resistor 23 limits the current of the voltage signal input to the comparator circuit 22 to prevent excessive current from damaging the comparator circuit 22; the first filter capacitor 24 filters the voltage signal input to the comparator circuit 22 to improve the stability and reliability of the comparator circuit 22. Similarly, the third current-limiting resistor 26 limits the current of the voltage signal input to the control unit 30 to prevent excessive current from damaging the control unit 30; the third filter capacitor 27 filters the voltage signal input to the control unit 30 to improve the reliability of the comparator circuit 22.

[0045] It should be noted that the above is only an exemplary example, and the specific circuits of the conversion circuit 21 and the comparator circuit 22 may include, but are not limited to, the following: Figure 2 As shown. In practical applications, Figure 2The first current-limiting resistor, the first filter capacitor, the third current-limiting resistor, and the third filter capacitor shown are optional configurations and can be set in the signal conversion circuit or not.

[0046] Optionally, the signal conversion circuit may also include a follower circuit, the input of which is connected to the conversion circuit, and the output of which is connected to a comparator circuit, so as to connect the conversion circuit and the comparator circuit and transmit the voltage signal output by the conversion circuit to the comparator circuit.

[0047] In one embodiment, a follower circuit can be provided between the conversion circuit and the comparator circuit. The input of the follower circuit is connected to the output of the conversion circuit, and the output of the follower circuit is connected to the input of the comparator circuit, so that the conversion circuit and the comparator circuit are connected through the follower circuit.

[0048] For example, the follower circuit may include an operational amplifier (hereinafter referred to as the second operational amplifier) ​​and a first functional resistor; the non-inverting input of the operational amplifier is connected to the conversion circuit, and the output of the operational amplifier is connected to the comparator circuit; one end of the first functional resistor is connected to the inverting input of the operational amplifier, and the other end is connected to the output of the operational amplifier.

[0049] See Figure 3 , Figure 3 This is a schematic diagram of the circuit principle of another signal conversion circuit provided in this application embodiment. As shown in Figure 3, the signal conversion circuit 20 further includes a follower circuit 28. The follower circuit 28 includes a second operational amplifier 281 and a first functional resistor 282. The non-inverting input terminal of the second operational amplifier 281 constitutes the input terminal of the follower circuit 28 and is connected to the output terminal of the conversion circuit 21. The output terminal of the second operational amplifier 281 constitutes the output terminal of the follower circuit 28 and is connected to the input terminal of the comparator circuit 22 (i.e., the non-inverting input terminal of the first operational amplifier 221) through the first current-limiting resistor 23.

[0050] One end of the first functional resistor 282 is connected to the inverting input terminal of the second operational amplifier 281, and the other end is connected to the output terminal of the second operational amplifier 281. The first functional resistor 282 is used to provide a DC feedback path to the second operational amplifier 281 during operation and to limit the current input to the second operational amplifier 281 through the inverting input terminal, so as to improve the stability of the second operational amplifier 281.

[0051] The positive voltage input terminal of the second operational amplifier 281 is connected to the voltage terminal, and the negative voltage input terminal is grounded, so that the power supply voltage of the voltage terminal supplies power to the second operational amplifier 281.

[0052] like Figure 3As shown, the follower circuit 28 also includes a fifth filter capacitor 283. One end of the fifth filter capacitor 283 is connected to the voltage terminal, and the other end is grounded. It is used to filter the voltage at the voltage input terminal of the second operational amplifier 281 to improve the stability and reliability of the second operational amplifier 281.

[0053] Combination Figure 2 and Figure 3 As shown, when the signal conversion circuit 20 includes a follower circuit 28, the conversion circuit 21 is connected to the comparator circuit 22 through the follower circuit 28 and the first current-limiting resistor 23; when the signal conversion circuit 20 does not include a follower circuit 28, the conversion circuit 21 is connected to the comparator circuit 22 through the first current-limiting resistor 23; or, when the signal conversion circuit 20 does not include the first current-limiting resistor 23, the conversion circuit 21 is connected to the comparator circuit 22 through the follower circuit 28.

[0054] In practical applications, the follower circuit has the characteristics of high input impedance and low output impedance. It can not only effectively reduce the loss of the voltage signal output by the conversion circuit during transmission, but also reduce the interference that the voltage signal may be subjected to during transmission or the distortion caused by load changes. It isolates the conversion circuit and the comparator circuit and avoids mutual interference between the speed circuit and the comparator circuit, thereby improving the stability and reliability of the signal conversion circuit.

[0055] It should be noted that the specific circuit structure of the follower circuit may include, but is not limited to, the following: Figure 3 As shown.

[0056] Optionally, the conversion circuit includes multiple second functional resistors connected in parallel, the multiple second functional resistors having equal resistance values, one end of the multiple second functional resistors being grounded, and the other end forming the input terminal of the conversion circuit for receiving the first pulse width modulation signal.

[0057] like Figure 3 As shown, the conversion circuit 21 consists of four parallel second functional resistors 201, all of which have the same resistance value. One end of each second functional resistor 201 is grounded, and the other end is connected to the output terminal of the current-type sensor 10.

[0058] It should be noted that the number of second functional resistors 201 included in the conversion circuit 21 may include, but is not limited to, four. It is only necessary to convert the first pulse width modulation signal into a voltage signal that meets the requirements of the comparator circuit 22.

[0059] In practical applications, the conversion circuit consists of multiple parallel secondary functional resistors. The circuit structure of the conversion circuit is relatively simple. At the same time, the multiple parallel secondary functional resistors enable the conversion circuit to withstand large current surges, thereby improving the reliability of the entire signal conversion circuit.

[0060] Optionally, the signal conversion circuit may further include a second current-limiting resistor and a second filter capacitor. One end of the second current-limiting resistor is connected to the output terminal of the conversion circuit, and the other end is connected to the input terminal of the follower circuit; one end of the second filter capacitor is grounded, and the other end is connected to the input terminal of the follower circuit.

[0061] like Figure 3 As shown, when the signal conversion circuit 20 includes a follower circuit 28, a second current-limiting resistor 29 and a second filter capacitor 210 can be provided in the signal conversion circuit 20. One end of the second current-limiting resistor 29 is connected to the output terminal of the conversion circuit 21, and the other end is connected to the input terminal of the follower circuit 28 (i.e., the non-inverting input terminal of the second operational amplifier 281). One end of the second filter capacitor 210 is grounded, and the other end is connected to the input terminal of the follower circuit 28. During the operation of the signal conversion circuit 20, the second current-limiting resistor 29 can limit the current in the input follower circuit 28, and the second filter capacitor 210 can filter the current in the input follower circuit 28, thereby improving the stability and reliability of the signal conversion circuit 20.

[0062] It is understandable that when the signal conversion circuit includes a follower circuit, a second current-limiting resistor, and a first current-limiting resistor, the conversion circuit is connected to the comparator circuit through the second current-limiting resistor, the follower circuit, and the first current-limiting resistor.

[0063] Optionally, the signal conversion circuit may also include a clamping diode, one end of which is connected to the input terminal of the conversion circuit, and the other end is grounded.

[0064] like Figure 3 As shown, the signal conversion circuit 20 may also include a clamping diode 211, which can be a transient voltage suppressor (TVS). The clamping diode 211 is connected in parallel with multiple second functional resistors 201. One end of the clamping diode 211 is grounded, and the other end is connected to the input / output terminal of the conversion circuit 21.

[0065] During the operation of the signal conversion circuit 20, when an electrostatic voltage appears at the input terminal of the signal conversion circuit 20, the clamping diode 211 will quickly conduct, clamping the electrostatic voltage within a safe range, thereby protecting the various components in the signal conversion circuit 20 from damage by high electrostatic voltage, thus improving the reliability and stability of the signal conversion circuit 20.

[0066] like Figure 3 As shown, the signal conversion circuit 20 also includes a third current-limiting resistor 26 and a third filter capacitor 27. For an understanding of the third current-limiting resistor 26 and the third filter capacitor 27, please refer to... Figure 2The specific details of this embodiment will not be elaborated upon here.

[0067] It should be noted that, in Figure 2 In the signal conversion circuit 20 shown, a clamping diode 211 can also be provided, but this embodiment will not be described in detail here.

[0068] like Figure 3 As shown, during the operation of the signal conversion circuit 20, when the current-type sensor 10 does not input the first pulse width modulation signal A to the signal conversion circuit 20, the pull-up resistor 25 inputs an initial high-level voltage to the control unit 30. When the current-type sensor 10 inputs the first pulse width modulation signal A to the signal conversion circuit 20, the conversion circuit 21 converts the current-type first pulse width modulation signal A output by the current-type sensor 10 into a periodically changing voltage signal. The periodically changing voltage signal is input to the follower circuit 28 through the second current-limiting resistor 29, and then input to the comparator circuit 22 through the follower circuit 28 and the first current-limiting resistor 23. The comparator circuit 22 converts the periodically changing voltage signal into a voltage-type second pulse width modulation signal, and the second pulse width modulation signal is input to the control unit 30 through the third current-limiting resistor 26.

[0069] During this process, the second current-limiting resistor limits the current of the input follower circuit signal, the second filter capacitor filters the input follower circuit signal, the first current-limiting resistor limits the current of the input comparator circuit signal, the first filter capacitor filters the input comparator circuit signal, the third current-limiting resistor limits the current of the input control unit signal, and the third filter capacitor filters the input control unit signal.

[0070] This application also provides a detection device, which includes the signal conversion circuit, current-type sensor, and control unit as described above. The current-type sensor is connected to the signal conversion circuit and is used to output a first pulse width modulation signal and input the first pulse width modulation signal to the signal conversion circuit; the signal conversion circuit is connected to the control unit and is used to convert the first pulse width modulation signal into a second pulse width modulation signal and input the second pulse width modulation signal to the control unit.

[0071] See Figure 4 , Figure 4 This is a schematic diagram illustrating an application scenario of a detection device provided in an embodiment of this application. For example... Figure 4 As shown, the detection device 40 can be installed in the vehicle 50. The detection device 40 includes a current-type sensor 10 (e.g., a current-type speed sensor), a signal conversion circuit 20, and a control unit 30. The signal output by the current-type sensor 10 is a current-type first pulse width modulation signal. The signal conversion circuit 20 can be... Figure 2 or Figure 3The signal conversion circuit 20 is shown. A current-type sensor 10 is connected to conversion circuit 21 within the signal conversion circuit 20. The sensor 10 converts the detected rotational speed into a current-type first pulse-width modulation (PWM) signal and inputs this first PWM signal to the signal conversion circuit 20. The signal conversion circuit 20 converts the first PWM signal into a second PWM signal and inputs this second PWM signal to the control unit 30. The control unit 30 can determine the actual rotational speed based on the frequency and duty cycle of the second PWM signal.

[0072] This application also provides a vehicle including an automatic transmission. The automatic transmission includes a detection device corresponding to the output shaft of the automatic transmission and an automatic transmission control unit. The detection device can convert the rotational speed of the output shaft into a second pulse width modulation signal and output the second pulse width modulation signal to the automatic transmission control unit. For an understanding of this vehicle, please refer to the foregoing examples; further details are omitted here.

[0073] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A signal conversion circuit, characterized in that, include: A conversion circuit, connected to a comparator circuit, is used to receive a first pulse width modulation signal output by a current-type sensor and convert the first pulse width modulation signal into a voltage signal to be output to the comparator circuit. The comparator circuit is configured to output a high-level voltage when the voltage signal is greater than the reference voltage, and to output a low-level voltage when the voltage signal is less than the reference voltage, so as to obtain a voltage-type second pulse width modulation signal composed of the high-level voltage and the low-level voltage.

2. The signal conversion circuit as described in claim 1, characterized in that, The signal conversion circuit further includes: A follower circuit is provided, the input of which is connected to the conversion circuit and the output of which is connected to the comparator circuit, so as to connect the conversion circuit and the comparator circuit and transmit the voltage signal output by the conversion circuit to the comparator circuit.

3. The signal conversion circuit as described in claim 2, characterized in that, The follower circuit includes an operational amplifier and a first functional resistor; The non-inverting input of the operational amplifier is connected to the conversion circuit, and the output of the operational amplifier is connected to the comparator circuit. One end of the first functional resistor is connected to the inverting input terminal of the operational amplifier, and the other end is connected to the output terminal of the operational amplifier.

4. The signal conversion circuit as described in claim 2, characterized in that, The signal conversion circuit further includes: A first current-limiting resistor, one end of which is connected to the output terminal of the follower circuit, and the other end of which is connected to the input terminal of the comparator circuit; The first filter capacitor has one end connected to the input terminal of the comparator circuit and the other end grounded.

5. The signal conversion circuit as described in claim 1, characterized in that, The conversion circuit includes multiple second functional resistors connected in parallel, the multiple second functional resistors having equal resistance values, one end of the multiple second functional resistors being grounded, and the other end forming the input terminal of the conversion circuit for receiving the first pulse width modulation signal.

6. The signal conversion circuit as described in claim 1, characterized in that, The signal conversion circuit further includes: A clamping diode, one end of which is connected to the input terminal of the conversion circuit, and the other end is grounded.

7. The signal conversion circuit as described in claim 2, characterized in that, The signal conversion circuit further includes: The second current-limiting resistor has one end connected to the output terminal of the conversion circuit and the other end connected to the input terminal of the follower circuit. The second filter capacitor has one end grounded and the other end connected to the input terminal of the follower circuit.

8. The signal conversion circuit as described in any one of claims 1-7, characterized in that, The signal conversion circuit further includes: The third current-limiting resistor has one end connected to the output terminal of the comparator circuit, and the other end forms the output terminal of the signal conversion circuit. The third filter capacitor has one end grounded and the other end connected to the output terminal of the signal conversion circuit.

9. A detection device, characterized in that, Includes the signal conversion circuit, current-type sensor, and control unit as described in any one of claims 1-8; The current-type sensor is connected to the signal conversion circuit and is used to output the first pulse width modulation signal and input the first pulse width modulation signal to the signal conversion circuit. The signal conversion circuit is connected to the control unit and is used to convert the first pulse width modulation signal into the second pulse width modulation signal and input the second pulse width modulation signal to the control unit.

10. A vehicle, characterized in that, The vehicle includes the detection device as described in claim 9.

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