A rotational speed signal adjustment circuit

Abstract

An embodiment of the present invention discloses a rotational speed signal adjustment circuit. The input end of the first follower circuit of the rotational speed signal adjustment circuit is electrically connected to the rotational speed signal output end. The input end of the isolation circuit is electrically connected to the output end of the first follower circuit. The output end of the isolation circuit is electrically connected to the input end of the second follower circuit. The output end of the second follower circuit is electrically connected to the input end of the in-phase attenuation circuit. The first follower circuit and the second follower circuit are used for the isolation circuit, and the in-phase attenuation circuit is used to adjust the voltage of the rotational speed signal to within the protection voltage range of the acquisition device. The above technical solution sets the first follower circuit at the input end of the isolation circuit and the second follower circuit at the output end of the isolation circuit, completely separating the front-stage circuit and the rear-stage circuit, greatly reducing the mutual interference between the front and rear circuits, and adjusting the voltage of the rotational speed signal to within the protection voltage range of the acquisition device through the in-phase attenuation circuit, reducing the risk of device damage.

Description

Technical Field

[0001] The present invention relates to the field of signal processing, and particularly to a rotational speed signal adjustment circuit. Background Art

[0002] A sensor is a detection device with a sensitive element as the core, which can convert the measured information into an electrical signal according to a certain rule. There are many types of rotational speed sensors, which are basically divided into magnetoelectric sensors, optoelectronic sensors, and Hall sensors. Due to the wide variety of sensor models on the market, the output voltage range is very wide. If directly collected by an A / D chip or a single-chip microcomputer, it may damage the device, and due to objective factors such as the on-site environment during installation, the signal directly output by the sensor will have glitches and other interferences, affecting the accuracy of collection. Summary of the Invention

[0003] The present invention provides a rotational speed signal adjustment circuit, which can greatly reduce the mutual interference between the front and rear circuits and reduce the risk of device damage.

[0004] In a first aspect, an embodiment of the present invention provides a rotational speed signal adjustment circuit, including a first follower circuit, an isolation circuit, a second follower circuit, and a non-inverting attenuation circuit; the first follower circuit includes a first follower circuit input terminal and a first follower circuit output terminal, the isolation circuit includes an isolation circuit input terminal and an isolation circuit output terminal, the second follower circuit includes a second follower circuit input terminal and a second follower circuit output terminal, and the non-inverting attenuation circuit includes a non-inverting attenuation circuit input terminal and a non-inverting attenuation circuit output terminal;

[0005] The first follower circuit input terminal is electrically connected to the rotational speed signal output terminal;

[0006] The isolation circuit input terminal is electrically connected to the first follower circuit output terminal; the isolation circuit output terminal is electrically connected to the second follower circuit input terminal; the second follower circuit output terminal is electrically connected to the non-inverting attenuation circuit input terminal;

[0007] The input impedance of the first follower circuit input terminal is greater than the output impedance of the first follower circuit output terminal, the input impedance of the second follower circuit input terminal is greater than the output impedance of the second follower circuit output terminal, and the first follower circuit and the second follower circuit are used for the isolation circuit;

[0008] The non-inverting attenuation circuit output terminal is electrically connected to the acquisition device; the non-inverting attenuation circuit is used to adjust the voltage of the rotational speed signal to within the protection voltage range of the acquisition device.

[0009] Optionally, the first follower circuit includes a first operational amplifier; the first operational amplifier includes a non-inverting input terminal of the first operational amplifier, an inverting input terminal of the first operational amplifier, a first power supply terminal of the first operational amplifier, a second power supply terminal of the first operational amplifier, and an output terminal of the first operational amplifier;

[0010] The non-inverting input terminal of the first operational amplifier is electrically connected to the rotational speed signal output terminal;

[0011] The output terminal of the first operational amplifier is electrically connected to the inverting input terminal of the first operational amplifier and the input terminal of the isolation circuit;

[0012] The first power supply terminal of the first operational amplifier is electrically connected to the positive power supply signal terminal, and the second power supply terminal of the first operational amplifier is electrically connected to the negative power supply signal terminal.

[0013] Optionally, the isolation circuit includes an isolation device; the isolation device includes a first power supply terminal of the isolation device, an input terminal of the isolation device, a first ground terminal of the isolation device, a second power supply terminal of the isolation device, a third power supply terminal of the isolation device, an output terminal of the isolation device, a second ground terminal of the isolation device, and a fourth power supply terminal of the isolation device;

[0014] Both the first power supply terminal of the isolation device and the third power supply terminal of the isolation device are electrically connected to the positive power supply signal terminal;

[0015] Both the second power supply terminal of the isolation device and the fourth power supply terminal of the isolation device are electrically connected to the negative power supply signal terminal;

[0016] Both the first ground terminal of the isolation device and the second ground terminal of the isolation device are electrically connected to the ground terminal;

[0017] The input terminal of the isolation device is electrically connected to the output terminal of the first follower circuit, and the output terminal of the isolation device is electrically connected to the input terminal of the second follower circuit.

[0018] Optionally, the second follower circuit includes a second operational amplifier; the second operational amplifier includes a non-inverting input terminal of the second operational amplifier, an inverting input terminal of the second operational amplifier, a first power supply terminal of the second operational amplifier, a second power supply terminal of the second operational amplifier, and an output terminal of the second operational amplifier;

[0019] The non-inverting input terminal of the second operational amplifier is electrically connected to the output terminal of the isolation circuit;

[0020] The output terminal of the second operational amplifier is electrically connected to the inverting input terminal of the second operational amplifier and the input terminal of the common-mode attenuation circuit;

[0021] The first power supply terminal of the second operational amplifier is electrically connected to the positive power supply signal terminal, and the second power supply terminal of the second operational amplifier is electrically connected to the negative power supply signal terminal.

[0022] Optionally, the in-phase attenuation circuit includes a third operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor; the third operational amplifier includes a non-inverting input terminal of the third operational amplifier, an inverting input terminal of the third operational amplifier, a first power supply terminal of the third operational amplifier, a second power supply terminal of the third operational amplifier, and an output terminal of the third operational amplifier;

[0023] The input terminal of the first resistor is electrically connected to the output terminal of the second follower circuit, the input terminal of the second resistor is electrically connected to the ground terminal, and the output terminals of the first resistor and the second resistor are both electrically connected to the non-inverting input terminal of the third operational amplifier;

[0024] The input terminal of the third resistor is electrically connected to the reference voltage terminal, the input terminal of the fourth resistor is electrically connected to the output terminal of the third operational amplifier, and the output terminals of the fourth resistor and the third resistor are both electrically connected to the inverting input terminal of the third operational amplifier;

[0025] The first power supply terminal of the third operational amplifier is electrically connected to the positive power supply signal terminal;

[0026] The second power supply terminal of the third operational amplifier is electrically connected to the negative power supply signal terminal.

[0027] Optionally, the input voltage of the in-phase attenuation circuit input terminal and the output voltage of the in-phase attenuation circuit output terminal satisfy a voltage adjustment formula;

[0028] The voltage adjustment formula includes

[0029]

[0030] wherein, V OUT is the output voltage of the in-phase attenuation circuit output terminal, V IN is the input voltage of the in-phase attenuation circuit input terminal, V REF is the reference voltage of the reference voltage terminal, R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, and R4 is the resistance value of the fourth resistor.

[0031] Optionally, the rotational speed signal adjustment circuit further includes a first protection circuit and a first filtering circuit; the first protection circuit and the first filtering circuit are arranged in the circuit between the first follower circuit and the rotational speed signal output terminal;

[0032] The first protection circuit includes a fifth resistor, a sixth resistor, and a first capacitor; the first filtering circuit includes a seventh resistor and a second capacitor;

[0033] The input end of the fifth resistor is electrically connected to the rotation speed signal output end, the output end of the fifth resistor is electrically connected to the first plate of the first capacitor, the input end of the sixth resistor is electrically connected to the positive power supply signal end, and the output end of the sixth resistor is electrically connected to the first plate of the first capacitor;

[0034] The second plate of the first capacitor is electrically connected to the input end of the seventh resistor; the output end of the seventh resistor is electrically connected to the first plate of the second capacitor; the second plate of the second capacitor is electrically connected to the ground end.

[0035] Optionally, the rotation speed signal adjustment circuit further includes a voltage dividing circuit; the voltage dividing circuit is located in the circuit between the first follower circuit and the isolation circuit; the voltage dividing circuit includes an eighth resistor and a ninth resistor;

[0036] The input end of the eighth resistor is electrically connected to the output end of the first follower circuit, the input end of the ninth resistor is electrically connected to the ground end, and the output ends of the eighth resistor and the ninth resistor are both electrically connected to the input end of the isolation circuit.

[0037] Optionally, the rotation speed signal adjustment circuit further includes a second protection circuit and a second filtering circuit;

[0038] The second protection circuit and the second filtering circuit are located in the circuit between the isolation circuit and the second follower circuit;

[0039] The second protection circuit includes a tenth resistor, and the second filtering circuit includes an eleventh resistor and a third capacitor;

[0040] The input end of the tenth resistor is electrically connected to the output end of the isolation circuit, the output end of the tenth resistor is electrically connected to the input end of the eleventh resistor, the output end of the eleventh resistor is electrically connected to the first plate of the third capacitor, and the second plate of the third capacitor is electrically connected to the ground end.

[0041] Optionally, the rotation speed signal adjustment circuit further includes a third filtering circuit, and the third filtering circuit includes a twelfth resistor and a fourth capacitor;

[0042] The input end of the twelfth resistor is electrically connected to the output end of the in-phase attenuation circuit;

[0043] The output end of the twelfth resistor is electrically connected to the first plate of the fourth capacitor, the second plate of the fourth capacitor is electrically connected to the ground end, and the output end of the twelfth resistor is further electrically connected to the acquisition device.

[0044] The rotational speed signal adjustment circuit in the present invention includes a first follower circuit, an isolation circuit, a second follower circuit, and a non-inverting attenuation circuit. The input end of the first follower circuit is electrically connected to the output end of the rotational speed signal. The input end of the isolation circuit is electrically connected to the output end of the first follower circuit. The output end of the isolation circuit is electrically connected to the input end of the second follower circuit. The output end of the second follower circuit is electrically connected to the input end of the non-inverting attenuation circuit. The input impedances of the input ends of the first follower circuit and the second follower circuit are both greater than the output impedances of the output ends of the first follower circuit and the second follower circuit. The first follower circuit and the second follower circuit are used for the isolation circuit. The output end of the non-inverting attenuation circuit is electrically connected to the acquisition device. The non-inverting attenuation circuit is used to adjust the voltage of the rotational speed signal to within the protection voltage range of the acquisition device. In this way, by setting the first follower circuit at the input end of the isolation circuit and the second follower circuit at the output end of the isolation circuit, the front-stage circuit and the rear-stage circuit are completely separated by the isolation circuit, greatly reducing the mutual interference between the front and rear circuits, improving the reliability of isolation, and adjusting the voltage of the rotational speed signal to within the protection voltage range of the acquisition device by the non-inverting attenuation circuit, reducing the risk of device damage, and solving the problems in the prior art that the rotational speed signal is vulnerable to interference and the risk of device damage is high when different acquisition devices are used. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 FIG. is a structural block diagram of a rotational speed signal adjustment circuit provided by an embodiment of the present invention;

[0046] Figure 2 FIG. is a partial circuit structure diagram of a rotational speed signal adjustment circuit provided by an embodiment of the present invention;

[0047] Figure 3 FIG. is a partial circuit structure diagram of another rotational speed signal adjustment circuit provided by an embodiment of the present invention;

[0048] Figure 4 FIG. is a partial circuit structure diagram of another rotational speed signal adjustment circuit provided by an embodiment of the present invention;

[0049] Figure 5 FIG. is a partial circuit structure diagram of another rotational speed signal adjustment circuit provided by an embodiment of the present invention;

[0050] Figure 6 FIG. is an overall block diagram of a rotational speed signal adjustment circuit provided by an embodiment of the present invention;

[0051] Figure 7 FIG. is an overall circuit structure diagram of a rotational speed signal adjustment circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will, in conjunction with the accompanying drawings in the embodiments of the present invention, fully describe the technical solutions of the present invention through specific implementation manners. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0053] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0054] Figure 1 is a structural block diagram of a rotational speed signal adjustment circuit provided by an embodiment of the present invention. Refer to Figure 1 , the rotational speed signal adjustment circuit includes a first follower circuit 10, an isolation circuit 20, a second follower circuit 30, and a non-inverting attenuation circuit 40. The first follower circuit 10 includes a first follower circuit input terminal 110 and a first follower circuit output terminal 120. The isolation circuit 20 includes an isolation circuit input terminal 210 and an isolation circuit output terminal 220. The second follower circuit 30 includes a second follower circuit input terminal 310 and a second follower circuit output terminal 330. The non-inverting attenuation circuit 40 includes a non-inverting attenuation circuit input terminal 410 and a non-inverting attenuation circuit output terminal 420. The first follower circuit input terminal 110 is electrically connected to the rotational speed signal output terminal 01. The isolation circuit input terminal 210 is electrically connected to the first follower circuit output terminal 120. The isolation circuit output terminal 220 is electrically connected to the second follower circuit input terminal 310. The second follower circuit output terminal 320 is electrically connected to the non-inverting attenuation circuit input terminal 410. The input impedance of the first follower circuit input terminal 110 is greater than the output impedance of the first follower circuit output terminal 120. The input impedance of the second follower circuit input terminal 310 is greater than the output impedance of the second follower circuit output terminal 320. The first follower circuit 10 and the second follower circuit 30 are used for the isolation circuit. The non-inverting attenuation circuit output terminal 420 is electrically connected to the acquisition device 02. The non-inverting attenuation circuit 40 is used to adjust the voltage of the rotational speed signal to within the protection voltage range of the acquisition device 02.

[0055] Specifically, as Figure 1As shown in the figure, the first follower circuit 10 and the second follower circuit 30 are respectively arranged at the input end 210 of the isolation circuit of the isolation circuit 20 and the output end 220 of the isolation circuit. Among them, the input impedance of the input end 110 of the first follower circuit 10 in the first follower circuit 10 is greater than the output impedance of the output end 120 of the first follower circuit. The input impedance is much greater than the output impedance. Thus, when connecting two circuits, the influence caused by direct connection between circuits can be reduced, playing a role of buffering protection and isolating circuits. Similarly, the input impedance of the input end 310 of the second follower circuit 30 in the second follower circuit 30 is greater than the output impedance of the output end 320 of the second follower circuit. The input impedance is much greater than the output impedance. Thus, when connecting two circuits, the influence caused by direct connection between circuits can be reduced, playing a role of buffering protection and isolating circuits. In this way, by arranging the first follower circuit 10 at the input end 210 of the isolation circuit of the isolation circuit 20, the voltage signal input to the isolation circuit 20 is isolated and protected, and by arranging the second follower circuit 30 at the output end 220 of the isolation circuit, the voltage signal output from the isolation circuit 20 is isolated and protected, improving the reliability of voltage isolation. At the same time, the isolation circuit 20 itself also has the function of isolating voltage. The front-stage circuit and the rear-stage circuit can be separated by the isolation circuit 20, further improving the effect and reliability of voltage isolation. In addition, the rotational speed signal adjustment circuit further includes a non-inverting attenuation circuit 40. The input end 410 of the non-inverting attenuation circuit of the non-inverting attenuation circuit 40 is connected to the output end 320 of the second follower circuit. Then, the voltage signal after isolation processing is input to the input end 410 of the non-inverting attenuation circuit. The non-inverting attenuation circuit 40 adjusts the voltage signal to the protection voltage range of the acquisition device 02. Finally, the output end 420 of the non-inverting attenuation circuit inputs the adjusted voltage signal into the acquisition device 02, thereby reducing the risk of damage to the acquisition device 02 on the basis of improving the measurement accuracy.

[0056] It should be noted that the protection voltage ranges of different acquisition devices 02 are different. Thus, during the adjustment process, the non-inverting attenuation circuit 40 needs to adjust the voltage of the rotational speed signal to the protection voltage range corresponding to the acquisition device 02 according to different acquisition devices 02.

[0057] In summary, in the rotational speed signal adjustment circuit according to the embodiment of the present invention, the input end of the first follower circuit is electrically connected to the rotational speed signal output end, the input end of the isolation circuit is electrically connected to the output end of the first follower circuit, the output end of the isolation circuit is electrically connected to the input end of the second follower circuit, the output end of the second follower circuit is electrically connected to the input end of the in-phase attenuation circuit. The input impedances of the input ends of the first follower circuit and the second follower circuit are both greater than the output impedances of the output ends of the first follower circuit and the second follower circuit. The first follower circuit and the second follower circuit are used for the isolation circuit, and the output end of the in-phase attenuation circuit is electrically connected to the acquisition device. The in-phase attenuation circuit is used to adjust the voltage of the rotational speed signal to the protection voltage range of the acquisition device. In this way, by setting the first follower circuit at the input end of the isolation circuit and the second follower circuit at the output end of the isolation circuit, the front-stage circuit and the rear-stage circuit are completely separated by the isolation circuit, greatly reducing the mutual interference between the front and rear circuits, improving the reliability of isolation, and adjusting the voltage of the rotational speed signal to the protection voltage range of the acquisition device through the in-phase attenuation circuit, reducing the risk of device damage, and solving the problems that the rotational speed signal in the prior art is vulnerable to interference and the risk of device damage is likely to occur when different acquisition devices are used.

[0058] Optionally, Figure 2 is a partial circuit structure diagram of a rotational speed signal adjustment circuit provided by an embodiment of the present invention. Refer to Figure 2 , the first follower circuit 10 includes a first operational amplifier 130. The first operational amplifier 130 includes a positive input terminal 131 of the first operational amplifier, a negative input terminal 132 of the first operational amplifier, a first power supply terminal 133 of the first operational amplifier, a second power supply terminal 134 of the first operational amplifier, and an output terminal 135 of the first operational amplifier. The positive input terminal 131 of the first operational amplifier is electrically connected to the rotational speed signal output terminal 01, the output terminal 135 of the first operational amplifier is electrically connected to the negative input terminal 132 of the first operational amplifier and the input terminal 210 of the isolation circuit, the first power supply terminal 133 of the first operational amplifier is electrically connected to the positive power supply signal terminal VCC, and the second power supply terminal 134 of the first operational amplifier is electrically connected to the negative power supply signal terminal -VCC.

[0059] Specifically, as Figure 2As shown, the first follower circuit 10 includes a first operational amplifier 130. The non-inverting input terminal 131 of the first operational amplifier is electrically connected to the rotational speed signal output terminal 01. Thus, the rotational speed signal output from the rotational speed signal output terminal 01 is input to the non-inverting input terminal 131 of the first operational amplifier. The inverting input terminal 132 of the first operational amplifier is electrically connected to the output terminal 135 of the first operational amplifier, forming a closed-loop negative feedback circuit, which has the characteristics of high input impedance, low output impedance, and a voltage gain approximately equal to 1. Thus, when the input impedance of the non-inverting input terminal 131 of the first operational amplifier is very high, it is equivalent to opening the previous-stage circuit. When the output impedance of the output terminal 135 of the first operational amplifier is very low, it is equivalent to a constant voltage source for the subsequent-stage circuit, that is, the output voltage is not affected by the impedance of the subsequent-stage circuit. Thus, the previous-stage circuit and the subsequent-stage circuit do not affect each other. The first power supply terminal 133 of the first operational amplifier is electrically connected to the positive power supply signal terminal VCC, and the second power supply terminal 134 of the first operational amplifier is electrically connected to the negative power supply signal terminal -VCC. Thus, a power supply is provided for the first operational amplifier 130.

[0060] Furthermore, Figure 3 is a partial circuit structure diagram of another rotational speed signal adjustment circuit provided by an embodiment of the present invention. Refer to Figure 3 , the isolation circuit 20 includes an isolation device 230. The isolation device 230 includes a first power supply terminal 231 of the isolation device, an input terminal 232 of the isolation device, a first ground terminal 233 of the isolation device, a second power supply terminal 234 of the isolation device, a third power supply terminal 235 of the isolation device, an output terminal 236 of the isolation device, a second ground terminal 237 of the isolation device, and a fourth power supply terminal 238 of the isolation device. The first power supply terminal 231 and the third power supply terminal 235 of the isolation device are both electrically connected to the positive power supply signal terminal VCC. The second power supply terminal 234 and the fourth power supply terminal 238 of the isolation device are both electrically connected to the negative power supply signal terminal -VCC. The first ground terminal 233 and the second ground terminal 237 of the isolation device are both electrically connected to the ground terminal GND. The input terminal 232 of the isolation device is electrically connected to the output terminal 236 of the first follower circuit. The output terminal 236 of the isolation device is electrically connected to the input terminal 310 of the second follower circuit.

[0061] Specifically, as Figure 3As shown, the isolation device 230 includes two groups of pins. The pins at its input end respectively include the first power supply terminal 231 of the isolation device, the input end 232 of the isolation device, the first ground terminal 233 of the isolation device, and the second power supply terminal 234 of the isolation device. The pins at the output end respectively include the third power supply terminal 235 of the isolation device, the output end 236 of the isolation device, the second ground terminal 237 of the isolation device, and the fourth power supply terminal 238 of the isolation device. Among them, both the first power supply terminal 231 of the isolation device and the third power supply terminal 235 of the isolation device are electrically connected to the positive power supply signal terminal VCC. Both the second power supply terminal 234 of the isolation device and the fourth power supply terminal 238 of the isolation device are electrically connected to the negative power supply signal terminal -VCC. That is, the input end pins and the output end pins are respectively powered by the independent positive power supply signal terminal VCC and negative power supply signal terminal -VCC. Thus, the front-stage circuit and the rear-stage circuit can be completely separated by the isolation device 230, greatly reducing the influence of mutual interference between the front and rear circuits. In addition, the input end 232 of the isolation device is electrically connected to the output end 120 of the first follower circuit, and the output end 236 of the isolation device is electrically connected to the input end 310 of the second follower circuit. Thus, the first follower circuit 10, the isolation circuit 20, and the second follower circuit 30 play a role of triple isolation, improving the voltage isolation effect. Moreover, when one of the circuits has a problem, the voltage can still be isolated through other circuits, improving the isolation reliability.

[0062] In another embodiment, Figure 4 is a partial circuit structure diagram of another rotational speed signal adjustment circuit provided by an embodiment of the present invention. Refer to Figure 4 , the second follower circuit 30 includes a second operational amplifier 330. The second operational amplifier 330 includes a non-inverting input terminal 331 of the second operational amplifier, an inverting input terminal 332 of the second operational amplifier, a first power supply terminal 333 of the second operational amplifier, a second power supply terminal 334 of the second operational amplifier, and an output terminal 335 of the second operational amplifier. The non-inverting input terminal 331 of the second operational amplifier is electrically connected to the output end 220 of the isolation circuit. The output terminal 335 of the second operational amplifier is electrically connected to the inverting input terminal 331 of the second operational amplifier and the input end 410 of the in-phase attenuation circuit. The first power supply terminal 333 of the second operational amplifier is electrically connected to the positive power supply signal terminal VCC. The second power supply terminal 334 of the second operational amplifier is electrically connected to the negative power supply signal terminal -VCC.

[0063] Specifically, as Figure 4As shown, the second follower circuit 30 includes a second operational amplifier 330. The non-inverting input terminal 331 of the second operational amplifier is electrically connected to the output terminal 220 of the isolation circuit. Thus, the signal output from the output terminal 220 of the isolation circuit is input to the non-inverting input terminal 331 of the second operational amplifier. The inverting input terminal 332 of the second operational amplifier is electrically connected to the output terminal 335 of the second operational amplifier, forming a closed-loop negative feedback circuit, which has the characteristics of high input impedance, low output impedance, and a voltage gain approximately equal to 1. Thus, when the input impedance of the non-inverting input terminal 331 of the second operational amplifier is very high, it is equivalent to opening the previous-stage circuit. When the output impedance of the output terminal 335 of the second operational amplifier is very low, it is equivalent to a constant voltage source for the subsequent-stage circuit, that is, the output voltage is not affected by the impedance of the subsequent-stage circuit. Thus, the previous-stage circuit and the subsequent-stage circuit do not affect each other. The first power supply terminal 333 of the second operational amplifier is electrically connected to the positive power supply signal terminal VCC, and the second power supply terminal 334 of the second operational amplifier is electrically connected to the negative power supply signal terminal -VCC. Thus, a power supply is provided for the second operational amplifier 330.

[0064] Furthermore, Figure 5 is a partial circuit structure diagram of another rotational speed signal adjustment circuit provided by an embodiment of the present invention. Refer to Figure 5 As shown, the non-inverting attenuation circuit 40 includes a third operational amplifier 430, a first resistor 440, a second resistor 450, a third resistor 460, and a fourth resistor 470. The third operational amplifier 430 includes a non-inverting input terminal 431, an inverting input terminal 432, a first power supply terminal 433, a second power supply terminal 434, and an output terminal 435 of the third operational amplifier. The input terminal of the first resistor 440 is electrically connected to the output terminal 320 of the second follower circuit. The input terminal of the second resistor 450 is electrically connected to the ground terminal GND. The output terminals of the first resistor 440 and the second resistor 450 are both electrically connected to the non-inverting input terminal 431 of the third operational amplifier. The input terminal of the third resistor 460 is electrically connected to the reference voltage terminal 480. The input terminal of the fourth resistor 470 is electrically connected to the output terminal 435 of the third operational amplifier. The output terminals of the fourth resistor 470 and the third resistor 460 are both electrically connected to the inverting input terminal 432 of the third operational amplifier. The first power supply terminal 433 of the third operational amplifier is electrically connected to the positive power supply signal terminal VCC, and the second power supply terminal 434 of the third operational amplifier is electrically connected to the negative power supply signal terminal -VCC.

[0065] Specifically, as Figure 5As shown in the figure, the in-phase attenuation circuit 40 includes a third operational amplifier 430, a first resistor 440, a second resistor 450, a third resistor 460, and a fourth resistor 470. Among them, the third operational amplifier 430 includes a positive input terminal 431 of the third operational amplifier, a negative input terminal 432 of the third operational amplifier, a first power supply terminal 433 of the third operational amplifier, a second power supply terminal 434 of the third operational amplifier, and an output terminal 435 of the third operational amplifier. Both the first resistor 440 and the second resistor 450 are located at the positive input terminal 431 of the third operational amplifier. The input terminal of the first resistor 440 is electrically connected to the output terminal 320 of the second follower circuit, and the input terminal of the second resistor 450 is electrically connected to the ground terminal GND. The output terminals of the first resistor 440 and the second resistor 450 are both electrically connected to the positive input terminal 431 of the third operational amplifier. In this way, the rotational speed signal isolated by the second follower circuit 30 is transmitted to the positive input terminal 431 of the third operational amplifier through the first resistor 440 and the second resistor 450. The third resistor 460 and the fourth resistor 470 are located between the negative input terminal 432 of the third operational amplifier and the reference voltage terminal 480. That is, the reference voltage of the reference voltage terminal 480 is applied to the negative input terminal 432 of the third operational amplifier by the inverting amplifier circuit composed of the third resistor 460 and the fourth resistor 470. The output terminal 435 of the third operational amplifier is also electrically connected to the acquisition device 02. Furthermore, the voltage of the isolated rotational speed signal is adjusted to the protection voltage range of the acquisition device 02 through the in-phase attenuator composed of the third operational amplifier 430, the first resistor 440, the second resistor 450, the third resistor 460, and the fourth resistor 470, reducing the risk of device damage.

[0066] Optionally, continue to refer to Figure 1 and Figure 5 , the input voltage of the in-phase attenuation circuit input terminal 410 and the output voltage of the in-phase attenuation circuit output terminal 420 satisfy the voltage adjustment formula;

[0067] The voltage adjustment formula includes:

[0068]

[0069] Among them, V OUT is the output voltage of the in-phase attenuation circuit output terminal 420, V IN is the input voltage of the in-phase attenuation circuit input terminal 410, V REF is the reference voltage of the reference voltage terminal 480, R1 is the resistance value of the first resistor 440, R2 is the resistance value of the second resistor 450, R3 is the resistance value of the third resistor 460, and R4 is the resistance value of the fourth resistor 470. Specifically, according to the circuit structure of the in-phase attenuation circuit 40, the voltage adjustment formula can be obtained, and then the reference voltage V REF, the resistance value R1 of the first resistor 440, the resistance value R2 of the second resistor 450, the resistance value R3 of the third resistor 460, the resistance value R4 of the fourth resistor 470, and the input voltage V of the in-phase attenuation circuit input terminal 410 IN , the voltage of the isolated rotational speed signal can be adjusted to the protection voltage range of the acquisition device 02. For example, when the acquisition device 02 is a single-chip microcomputer, the voltage of the isolated rotational speed signal can be adjusted to within 24V through the voltage adjustment formula, thereby preventing the acquisition device 02 from being damaged due to the excessive voltage of the rotational speed signal.

[0070] Optionally, Figure 6 is the overall block diagram of a rotational speed signal adjustment circuit provided by an embodiment of the present invention. Figure 7 is the overall circuit structure diagram of a rotational speed signal adjustment circuit provided by an embodiment of the present invention. As Figure 6 and Figure 7 shown, the rotational speed signal adjustment circuit further includes a first protection circuit 50 and a first filtering circuit 60. The first protection circuit 50 and the first filtering circuit 60 are arranged in the circuit between the first following circuit 10 and the rotational speed signal output terminal 01. The first protection circuit 50 includes a fifth resistor 510, a sixth resistor 520, and a first capacitor 530. The first filtering circuit 60 includes a seventh resistor 610 and a second capacitor 620. The input end of the fifth resistor 510 is electrically connected to the rotational speed signal output terminal 01. The output end of the fifth resistor 510 is electrically connected to the first plate of the first capacitor 530. The input end of the sixth resistor 520 is electrically connected to the positive power supply signal terminal VCC. The output end of the sixth resistor 520 is electrically connected to the first plate of the first capacitor 530. The second plate of the first capacitor 530 is electrically connected to the input end of the seventh resistor 610. The output end of the seventh resistor 610 is electrically connected to the first plate of the second capacitor 620. The second plate of the second capacitor 620 is electrically connected to the ground terminal GND.

[0071] Specifically, as Figure 6 and Figure 7As shown, the rotational speed signal adjustment circuit further includes a first protection circuit 50 and a first filtering circuit 60 in the circuit between the first follower circuit 10 and the rotational speed signal output terminal 01. The rotational speed signal output from the rotational speed signal output terminal 01 is transmitted to the inverting input terminal 131 of the first operational amplifier in the first follower circuit 10 after being current-limited by the first protection circuit 50 and filtering out high-frequency signals by the first filtering circuit 60. Among them, the first protection circuit 50 includes a fifth resistor 510 and a sixth resistor 520. The output terminals of the fifth resistor 510 and the sixth resistor 520 are connected to the same node, and thus the rotational speed signal output from the rotational speed signal output terminal 01 is current-limited through the fifth resistor 510 and the sixth resistor 520 to prevent device damage caused by overcurrent. The first protection circuit 50 further includes a first capacitor 530. The output terminals of the fifth resistor 510 and the sixth resistor 520 are connected to the first plate of the first capacitor 530, and thus the DC component in the rotational speed signal is isolated through the first capacitor 530 to prevent the DC component from causing magnetic bias in the power transformer, thereby triggering a series of impacts and interferences. The first filtering circuit 60 includes a seventh resistor 610 and a second capacitor 620. The output terminal of the seventh resistor 610 is electrically connected to the first plate of the second capacitor 620. The second plate of the second capacitor 620 is electrically connected to the ground terminal GND. The output terminal of the seventh resistor 610 is also connected to the inverting input terminal 131 of the first operational amplifier in the first follower circuit 10. Thus, after filtering out the high-frequency signals in the rotational speed signal through the seventh resistor 610 and the second capacitor 620, it is transmitted to the first follower circuit 10. In this way, through the first protection circuit 50 and the first filtering circuit 60, the rotational speed signal input into the first follower circuit 10 is current-limited, isolated, and filtered, thereby removing the influence of other factors and improving the measurement accuracy.

[0072] Optionally, continue to refer to Figure 6 and Figure 7 , the rotational speed signal adjustment circuit further includes a voltage dividing circuit 70. The voltage dividing circuit 70 is in the circuit between the first follower circuit 10 and the isolation circuit 20. The voltage dividing circuit 70 includes an eighth resistor 710 and a ninth resistor 720. The input terminal of the eighth resistor 710 is electrically connected to the output terminal 120 of the first follower circuit. The input terminal of the ninth resistor 720 is electrically connected to the ground terminal GND. The output terminals of the eighth resistor 710 and the ninth resistor 720 are both electrically connected to the input terminal 210 of the isolation circuit.

[0073] Specifically, as Figure 6 and Figure 7As shown, the rotational speed signal adjustment circuit further includes a voltage dividing circuit 70 in the circuit located between the first follower circuit 10 and the isolation circuit 20. One end of the voltage dividing circuit 70 is connected to the output end 120 of the first follower circuit, and the other end is connected to the input end 210 of the isolation circuit. That is to say, the voltage dividing circuit 70 is located between the output end 135 of the first operational amplifier and the input end 232 of the isolation device. The voltage dividing circuit 70 includes an eighth resistor 710 and a ninth resistor 720. The input end of the eighth resistor 710 is electrically connected to the output end 120 of the first follower circuit, the input end of the ninth resistor 720 is electrically connected to the ground terminal GND, and the output ends of the eighth resistor 710 and the ninth resistor 720 are both electrically connected to the input end 210 of the isolation circuit. Furthermore, the rotational speed signal output by the output end 135 of the first operational amplifier is divided by the eighth resistor 710 and the ninth resistor 720 to prevent the voltage of the rotational speed signal from being too large and damaging electronic devices.

[0074] Optionally, continue to refer to Figure 6 and Figure 7 , the rotational speed signal adjustment circuit further includes a second protection circuit 80 and a second filtering circuit 90. The second protection circuit 80 and the second filtering circuit 90 are in the circuit located between the isolation circuit 20 and the second follower circuit 30. The second protection circuit 80 includes a tenth resistor 810, and the second filtering circuit 90 includes an eleventh resistor 910 and a third capacitor 920. The input end of the tenth resistor 810 is electrically connected to the output end 220 of the isolation circuit, the output end of the tenth resistor 810 is electrically connected to the input end of the eleventh resistor 910, the output end of the eleventh resistor 910 is electrically connected to the first electrode plate of the third capacitor 920, and the second electrode plate of the third capacitor 920 is electrically connected to the ground terminal GND.

[0075] Specifically, as Figure 6 and Figure 7As shown, the second protection circuit 80 and the second filtering circuit 90 are located in the circuit between the isolation circuit 20 and the second follower circuit 30. One end of the second protection circuit 80 is electrically connected to the output terminal 220 of the isolation circuit. The other end of the second protection circuit 80 is connected to one end of the second filtering circuit 90. The other end of the second filtering circuit 90 is electrically connected to the input terminal 310 of the second follower circuit. That is, the second protection circuit 80 and the second filtering circuit 90 are located between the output terminal 220 of the isolation device and the non-inverting input terminal 331 of the third operational amplifier. The second protection circuit 80 includes a tenth resistor 810. The second filtering circuit 90 includes an eleventh resistor 910 and a third capacitor 920. The input terminal of the tenth resistor 810 is electrically connected to the output terminal 236 of the isolation device. The output terminal of the tenth resistor 810 is electrically connected to the input terminal of the eleventh resistor 910. The output terminal of the eleventh resistor 910 is electrically connected to the first plate of the third capacitor 920. The second plate of the third capacitor 920 is electrically connected to the ground terminal GND. The output terminal of the eleventh resistor 910 and the first plate of the third capacitor 920 are both electrically connected to the non-inverting input terminal 331 of the third operational amplifier. Furthermore, the rotation speed signal output from the output terminal 236 of the isolation device is current-limited through the tenth resistor 810 to protect the device. In addition, through the eleventh resistor 910 and the third capacitor 920 located at the output terminal 236 of the isolation device, the high-frequency signals in the rotation speed signal are filtered again, thereby removing the influence of other factors and further improving the measurement accuracy.

[0076] Optionally, continue to refer to Figure 6 and Figure 7 , the rotation speed signal adjustment circuit further includes a third filtering circuit 100. The third filtering circuit 100 includes a twelfth resistor 200 and a fourth capacitor 300. The input terminal of the twelfth resistor 200 is electrically connected to the output terminal 420 of the non-inverting attenuation circuit. The output terminal of the twelfth resistor 200 is electrically connected to the first plate of the fourth capacitor 300. The second plate of the fourth capacitor 300 is electrically connected to the ground terminal GND. The output terminal of the twelfth resistor 200 is also electrically connected to the acquisition device 02.

[0077] Specifically, a third filter circuit 100 is further included between the in-phase attenuation circuit 40 and the acquisition device 02. One end of the third filter circuit 100 is electrically connected to the output end 420 of the in-phase attenuation circuit, and the other end is also electrically connected to the output end 420 of the in-phase attenuation circuit. That is to say, the third filter circuit 100 is located between the output end 435 of the fourth operational amplifier and the acquisition device 02. The third filter circuit 100 includes a twelfth resistor 200 and a fourth capacitor 300. The input end of the twelfth resistor 200 is electrically connected to the output end 435 of the fourth operational amplifier. The output end of the twelfth resistor 200 is electrically connected to the first plate of the fourth capacitor 300. The second plate of the fourth capacitor 300 is electrically connected to the ground terminal GND. The output end of the twelfth resistor 200 is also electrically connected to the acquisition device 02. Furthermore, after the in-phase attenuation circuit 40 adjusts the voltage of the rotational speed signal to the protection voltage range of the acquisition device 02, high-frequency signals are filtered out again through the twelfth resistor 200 and the fourth capacitor 300, thereby removing the influence of other factors and further improving the measurement accuracy.

[0078] Note that the above is only a preferred embodiment of the present invention and the applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments, combinations with each other, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A rotational speed signal regulating circuit, characterized in that, It includes a first follower circuit, an isolation circuit, a second follower circuit, and a non-inverting attenuation circuit; the first follower circuit includes a first follower circuit input terminal and a first follower circuit output terminal, the isolation circuit includes an isolation circuit input terminal and an isolation circuit output terminal, the second follower circuit includes a second follower circuit input terminal and a second follower circuit output terminal, and the non-inverting attenuation circuit includes a non-inverting attenuation circuit input terminal and a non-inverting attenuation circuit output terminal; The first follower circuit input terminal is electrically connected to the rotational speed signal output terminal; The isolation circuit input terminal is electrically connected to the first follower circuit output terminal; the isolation circuit output terminal is electrically connected to the second follower circuit input terminal; the second follower circuit output terminal is electrically connected to the non-inverting attenuation circuit input terminal; The input impedance of the first follower circuit input terminal is greater than the output impedance of the first follower circuit output terminal, the input impedance of the second follower circuit input terminal is greater than the output impedance of the second follower circuit output terminal, and the first follower circuit and the second follower circuit are used for the isolation circuit; The non-inverting attenuation circuit output terminal is electrically connected to the acquisition device; the non-inverting attenuation circuit is used to adjust the voltage of the rotational speed signal to within the protection voltage range of the acquisition device.

2. The rotational speed signal regulating circuit according to claim 1, wherein The first follower circuit includes a first operational amplifier; the first operational amplifier includes a first operational amplifier non-inverting input terminal, a first operational amplifier inverting input terminal, a first operational amplifier first power supply terminal, a first operational amplifier second power supply terminal, and a first operational amplifier output terminal; The first operational amplifier non-inverting input terminal is electrically connected to the rotational speed signal output terminal; The first operational amplifier output terminal is electrically connected to the first operational amplifier inverting input terminal and the isolation circuit input terminal; The first operational amplifier first power supply terminal is electrically connected to the positive power supply signal terminal, and the first operational amplifier second power supply terminal is electrically connected to the negative power supply signal terminal.

3. The rotational speed signal regulating circuit according to claim 1, wherein The isolation circuit includes an isolation device; the isolation device includes an isolation device first power supply terminal, an isolation device input terminal, an isolation device first ground terminal, an isolation device second power supply terminal, an isolation device third power supply terminal, an isolation device output terminal, an isolation device second ground terminal, and an isolation device fourth power supply terminal; Both the isolation device first power supply terminal and the isolation device third power supply terminal are electrically connected to the positive power supply signal terminal; Both the isolation device second power supply terminal and the isolation device fourth power supply terminal are electrically connected to the negative power supply signal terminal; Both the isolation device first ground terminal and the isolation device second ground terminal are electrically connected to the ground terminal; The isolation device input terminal is electrically connected to the first follower circuit output terminal, and the isolation device output terminal is electrically connected to the second follower circuit input terminal.

4. The rotational speed signal regulating circuit according to claim 1, wherein The second follower circuit includes a second operational amplifier; the second operational amplifier includes a second operational amplifier non-inverting input terminal, a second operational amplifier inverting input terminal, a second operational amplifier first power supply terminal, a second operational amplifier second power supply terminal, and a second operational amplifier output terminal; The second operational amplifier non-inverting input terminal is electrically connected to the isolation circuit output terminal; The output terminal of the second operational amplifier is electrically connected to the inverting input terminal of the second operational amplifier and the input terminal of the in-phase attenuation circuit; The first power supply terminal of the second operational amplifier is electrically connected to the positive power supply signal terminal, and the second power supply terminal of the second operational amplifier is electrically connected to the negative power supply signal terminal.

5. The rotational speed signal regulating circuit according to claim 1, wherein The in-phase attenuation circuit includes a third operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor; the third operational amplifier includes a non-inverting input terminal of the third operational amplifier, an inverting input terminal of the third operational amplifier, a first power supply terminal of the third operational amplifier, a second power supply terminal of the third operational amplifier, and an output terminal of the third operational amplifier; The input terminal of the first resistor is electrically connected to the output terminal of the second follower circuit, the input terminal of the second resistor is electrically connected to the ground terminal, and the output terminals of the first resistor and the second resistor are both electrically connected to the non-inverting input terminal of the third operational amplifier; The input terminal of the third resistor is electrically connected to the reference voltage terminal, the input terminal of the fourth resistor is electrically connected to the output terminal of the third operational amplifier, and the output terminals of the fourth resistor and the third resistor are both electrically connected to the inverting input terminal of the third operational amplifier; The first power supply terminal of the third operational amplifier is electrically connected to the positive power supply signal terminal; The second power supply terminal of the third operational amplifier is electrically connected to the negative power supply signal terminal.

6. The rotational speed signal adjustment circuit according to claim 5, characterized in that The input voltage at the input terminal of the in-phase attenuation circuit and the output voltage at the output terminal of the in-phase attenuation circuit satisfy a voltage regulation formula; The voltage regulation formula includes: Among them, V OUT is the output voltage at the output end of the in-phase attenuation circuit, and V IN is the input voltage at the input end of the in-phase attenuation circuit. V REF is the reference voltage at the reference voltage terminal. R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, and R4 is the resistance value of the fourth resistor.

7. The rotational speed signal regulating circuit according to claim 1, wherein The rotational speed signal conditioning circuit further includes a first protection circuit and a first filtering circuit; the first protection circuit and the first filtering circuit are arranged in the circuit between the first follower circuit and the rotational speed signal output terminal; The first protection circuit includes a fifth resistor, a sixth resistor, and a first capacitor; the first filtering circuit includes a seventh resistor and a second capacitor; The input terminal of the fifth resistor is electrically connected to the rotational speed signal output terminal, the output terminal of the fifth resistor is electrically connected to the first plate of the first capacitor, the input terminal of the sixth resistor is electrically connected to the positive power supply signal terminal, and the output terminal of the sixth resistor is electrically connected to the first plate of the first capacitor; The second plate of the first capacitor is electrically connected to the input terminal of the seventh resistor; the output terminal of the seventh resistor is electrically connected to the first plate of the second capacitor; the second plate of the second capacitor is electrically connected to the ground terminal.

8. The rotational speed signal regulating circuit according to claim 1, wherein The rotational speed signal conditioning circuit further includes a voltage dividing circuit; the voltage dividing circuit is located in the circuit between the first follower circuit and the isolation circuit; the voltage dividing circuit includes an eighth resistor and a ninth resistor; The input terminal of the eighth resistor is electrically connected to the output terminal of the first follower circuit, the input terminal of the ninth resistor is electrically connected to the ground terminal, and the output terminals of the eighth resistor and the ninth resistor are both electrically connected to the input terminal of the isolation circuit.

9. The rotational speed signal regulating circuit according to claim 1, wherein The rotational speed signal conditioning circuit further includes a second protection circuit and a second filtering circuit; The second protection circuit and the second filtering circuit are located in the circuit between the isolation circuit and the second follower circuit; The second protection circuit includes a tenth resistor, and the second filtering circuit includes an eleventh resistor and a third capacitor; The input end of the tenth resistor is electrically connected to the output end of the isolation circuit, the output end of the tenth resistor is electrically connected to the input end of the eleventh resistor, the output end of the eleventh resistor is electrically connected to the first plate of the third capacitor, and the second plate of the third capacitor is electrically connected to the ground terminal.

10. The rotational speed signal regulating circuit according to claim 1, characterized in that The rotational speed signal adjustment circuit further includes a third filtering circuit, and the third filtering circuit includes a twelfth resistor and a fourth capacitor; The input end of the twelfth resistor is electrically connected to the output end of the in-phase attenuation circuit; The output end of the twelfth resistor is electrically connected to the first plate of the fourth capacitor, the second plate of the fourth capacitor is electrically connected to the ground terminal, and the output end of the twelfth resistor is further electrically connected to the acquisition device.

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