A double-threshold high-reliability sensor signal acquisition interface protection circuit

Abstract

This invention relates to a dual-threshold, high-reliability sensor signal acquisition interface protection circuit design, employing an interface LC filter and a dual-threshold protection method. The sensor resistance signal enters the product through a connector, first passing through an LC filter circuit to remove external interference signals. A bridge circuit converts the sensor resistance signal into a voltage signal, which is then protected by a dual-threshold clamping circuit for current and voltage limiting. The processed signal then enters an analog switch chip for time-division switching for subsequent AD conversion. This invention achieves interface voltage clamping and current limiting of the sensor signal, effectively protecting the internal downstream chips and improving circuit reliability.

Description

Technical Field

[0001] This invention relates to the field of aviation environmental control, and specifically to a protection circuit for a dual-threshold high-reliability sensor signal acquisition interface. Background Technology

[0002] With the rapid development of all-electric and more-electric aircraft, sensors, as core components for information acquisition and health monitoring, directly impact the safety and reliability of the entire system due to the stability of their signal acquisition. However, sensor interfaces are typically exposed to complex operating environments, making them susceptible to external interference (such as electromagnetic interference and radio frequency interference) and potential electrical threats (such as overvoltage, overcurrent, and electrostatic discharge). These problems can lead to sensor damage, data transmission errors, and even malfunctions in the data acquisition and control devices. Summary of the Invention

[0003] The purpose of this invention is to provide a dual-threshold high-reliability sensor signal acquisition interface protection circuit in complex aerospace electrical environments, thereby realizing high-reliability sensor acquisition technology in environmental control systems.

[0004] The objective of this invention can be achieved through the following technical solutions: A dual-threshold high-reliability sensor signal acquisition interface protection circuit is disclosed. The interface protection circuit includes a main processor, an analog switch, and multiple filtering protection circuits, wherein the output of each filtering protection circuit is connected to one input of the analog switch. The main processor is used to control the switching of multiple filtering protection circuits in the analog switch to acquire multiple sensor signals in a time-division multiplexing manner.

[0005] Furthermore, Each filtering and protection circuit includes an LC filter circuit, a data acquisition bridge, a current limiting protection circuit, and a dual threshold voltage clamping circuit connected in series.

[0006] Furthermore, The sensor signal enters the interface protection circuit through the connector. First, it passes through the LC filter circuit to filter out external interference signals. The acquisition bridge converts the sensor resistance signal into a voltage signal. Then, it passes through the dual threshold voltage clamping circuit for current and voltage limiting protection.

[0007] Furthermore, The LC filter circuit consists of capacitors C1-1, C1-2, C1-3, and C1-4, and ferrite beads E1-1 and E1-2. The sensor's dual-ended input signals MGQ1+ and MGQ1- are connected in parallel with capacitors C1-1 and C1-3 to the chassis ground EARTH, respectively. The dual-ended input signals MGQ1+ and MGQ1- are connected in series with magnetic beads E1-1 and E1-2, respectively. The series-connected signals are connected in parallel with capacitors C1-2 and C1-4 to the signal ground SGND, respectively.

[0008] Furthermore, The data acquisition bridge consists of capacitor C1-5 and resistors R1-1, R1-2, and R1-3; The two sensor signals after LC filtering are connected in parallel with C1-5, and then connected in series with the +15V power supply bridge. The series connection order is as follows: +15V is connected to R1-1, the other end of R1-1 is connected to one end of R1-2, the other end of R1-2 is connected to one end of C1-5, the other end of C1-5 is connected to one end of R1-3, and the other end of R1-3 is connected to signal ground SGND.

[0009] Furthermore, The t1 signal is the voltage division value of the sensor after bridge conditioning. The t1 voltage changes synchronously with the change of the sensor resistance signal.

[0010] Furthermore, In the bridge circuit, resistor R1-2 is an adjustable resistor ranging from 1 to 100 Ω, used to compensate for errors caused by individual differences in the circuit and components, and to ensure the accuracy of data acquisition.

[0011] Furthermore, t1 performs secondary filtering on the parallel capacitor C1-6 to the signal ground SGND, and then the series resistor R1-4 is used for current limiting protection to prevent overcurrent burn-out of the input pin of the subsequent analog switch.

[0012] Furthermore, The dual threshold voltage clamping circuit consists of diodes D1-1 and D1-2; The signal t1_in after two-stage filtering is subjected to dual threshold clamping. t1_in is connected to the positive terminal of diode D1-1, and the negative terminal of D1-1 is connected to +15V. At the same time, t1_in is connected to the negative terminal of diode D1-2, and the positive terminal of D1-2 is connected to -15V. Due to the voltage clamping characteristics of diodes, this circuit limits the voltage range of t1_in to between -15.7V and +15.7V to prevent overvoltage burn-out of the input pins of the subsequent analog switch.

[0013] Furthermore, The t1_in signal, after being current-limited and dual-threshold voltage-limited, is connected to analog switch U1. The main processor controls the high and low levels of the chip select signal of analog switch U1 to select the input of multiple analog switches in a time-division multiplexing manner, and outputs reliable sensor signals for subsequent operational amplification and AD conversion.

[0014] The beneficial effects of this invention are: This invention is a dual-threshold, high-reliability sensor signal acquisition interface protection circuit design. It adopts an interface LC filtering and dual protection threshold design method, which is simple and reliable, suitable for complex aerospace electrical environments, and realizes interface voltage clamping and current limiting of sensor signals, effectively protecting the internal downstream chips of the product and improving circuit reliability. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 Block diagram of the protection circuit for the signal acquisition interface of a dual-threshold high-reliability sensor; Figure 2 This is a schematic diagram of a protection circuit for the signal acquisition interface of a dual-threshold high-reliability sensor. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0018] This invention provides a dual-threshold high-reliability sensor signal acquisition interface protection circuit. The interface protection circuit includes: a main processor, an analog switch, and multiple filtering protection circuits, with the output of each filtering protection circuit connected to one input of the analog switch. The main processor is used to control the switching of multiple filtering protection circuits in the analog switch to acquire multiple sensor signals in a time-division multiplexing manner.

[0019] Each filtering and protection circuit includes an LC filter circuit, a data acquisition bridge, a current limiting protection circuit, and a dual threshold voltage clamping circuit connected in series.

[0020] The sensor signal enters the interface protection circuit through the connector. First, it passes through the LC filter circuit to filter out external interference signals. The acquisition bridge converts the sensor resistance signal into a voltage signal. Then, it passes through the dual threshold voltage clamping circuit for current and voltage limiting protection.

[0021] The LC filter circuit consists of capacitors C1-1, C1-2, C1-3, and C1-4, and ferrite beads E1-1 and E1-2. The sensor's dual-ended input signals MGQ1+ and MGQ1- are connected in parallel with capacitors C1-1 and C1-3 to the chassis ground EARTH, respectively. The dual-ended input signals MGQ1+ and MGQ1- are connected in series with magnetic beads E1-1 and E1-2, respectively. The series-connected signals are connected in parallel with capacitors C1-2 and C1-4 to the signal ground SGND, respectively.

[0022] The data acquisition bridge consists of capacitor C1-5 and resistors R1-1, R1-2, and R1-3; The two sensor signals after LC filtering are connected in parallel with C1-5, and then connected in series with the +15V power supply bridge. The series connection order is as follows: +15V is connected to R1-1, the other end of R1-1 is connected to one end of R1-2, the other end of R1-2 is connected to one end of C1-5, the other end of C1-5 is connected to one end of R1-3, and the other end of R1-3 is connected to signal ground SGND.

[0023] The t1 signal is the voltage division value of the sensor after bridge conditioning. The t1 voltage changes synchronously with the change of the sensor resistance signal.

[0024] In the bridge circuit, resistor R1-2 is an adjustable resistor ranging from 1 to 100 Ω, used to compensate for errors caused by individual differences in the circuit and components, and to ensure the accuracy of data acquisition.

[0025] t1 performs secondary filtering on the parallel capacitor C1-6 to the signal ground SGND, and then the series resistor R1-4 is used for current limiting protection to prevent overcurrent burn-out of the input pin of the subsequent analog switch.

[0026] The dual threshold voltage clamping circuit consists of diodes D1-1 and D1-2; The signal t1_in after two-stage filtering is subjected to dual threshold clamping. t1_in is connected to the positive terminal of diode D1-1, and the negative terminal of D1-1 is connected to +15V. At the same time, t1_in is connected to the negative terminal of diode D1-2, and the positive terminal of D1-2 is connected to -15V. Due to the voltage clamping characteristics of diodes, this circuit limits the voltage range of t1_in to between -15.7V and +15.7V to prevent overvoltage burn-out of the input pins of the subsequent analog switch.

[0027] The t1_in signal, after being current-limited and dual-threshold voltage-limited, is connected to analog switch U1. The main processor controls the high and low levels of the chip select signal of analog switch U1 to select the input of multiple analog switches in a time-division multiplexing manner, and outputs reliable sensor signals for subsequent operational amplification and AD conversion.

[0028] Example 1 like Figure 1 and Figure 2 As shown, a dual-threshold high-reliability sensor signal acquisition interface protection circuit is provided. The sensor signal enters the controller and is filtered out by an LC filter circuit to remove external interference noise. The resistance signal is converted into a voltage signal by an acquisition bridge. The current and voltage connected to the analog switch are limited to the chip's tolerance range by a current limiting circuit and a dual-threshold voltage clamping circuit, thus achieving protection of the acquisition interface.

[0029] A single analog switch can be externally connected to expand up to 8 channels of dual-threshold high-reliability sensor signal acquisition interface protection circuits. The main processor controls the high and low levels of pins 16, 1, and 4 of the U1 analog switch chip, and the time-division multiplexing uses the same signal processing method as t1_in and is connected to the t1_in pin of the U1 analog switch. nThe _in signal is output to pin 12 of U1 and can be used for subsequent operational amplification and AD conversion.

[0030] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A protection circuit for a dual-threshold high-reliability sensor signal acquisition interface, characterized in that, The interface protection circuit includes: a main processor, an analog switch, and multiple filter protection circuits, with the output of each filter protection circuit connected to one input of the analog switch; the main processor is used to control the switching of multiple filter protection circuits in the analog switch and to collect multiple sensor signals in a time-division manner.

2. The dual-threshold high-reliability sensor signal acquisition interface protection circuit according to claim 1, characterized in that, Each filtering and protection circuit includes an LC filter circuit, a data acquisition bridge, a current limiting protection circuit, and a dual threshold voltage clamping circuit connected in series.

3. The dual-threshold high-reliability sensor signal acquisition interface protection circuit according to claim 2, characterized in that, The sensor signal enters the interface protection circuit through the connector. First, it passes through the LC filter circuit to filter out external interference signals. The acquisition bridge converts the sensor resistance signal into a voltage signal. Then, it passes through the dual threshold voltage clamping circuit for current and voltage limiting protection.

4. The dual-threshold high-reliability sensor signal acquisition interface protection circuit according to claim 2, characterized in that, The LC filter circuit consists of capacitors C1-1, C1-2, C1-3, and C1-4, and ferrite beads E1-1 and E1-2. The sensor's dual-ended input signals MGQ1+ and MGQ1- are connected in parallel with capacitors C1-1 and C1-3 to the chassis ground EARTH, respectively. The dual-ended input signals MGQ1+ and MGQ1- are connected in series with magnetic beads E1-1 and E1-2, respectively. The series-connected signals are connected in parallel with capacitors C1-2 and C1-4 to the signal ground SGND, respectively.

5. The dual-threshold high-reliability sensor signal acquisition interface protection circuit according to claim 4, characterized in that, The data acquisition bridge consists of capacitor C1-5 and resistors R1-1, R1-2, and R1-3; The two sensor signals after LC filtering are connected in parallel with C1-5, and then connected in series with the +15V power supply bridge. The series connection order is as follows: +15V is connected to R1-1, the other end of R1-1 is connected to one end of R1-2, the other end of R1-2 is connected to one end of C1-5, the other end of C1-5 is connected to one end of R1-3, and the other end of R1-3 is connected to signal ground SGND.

6. The dual-threshold high-reliability sensor signal acquisition interface protection circuit according to claim 5, characterized in that, The t1 signal is the voltage division value of the sensor after bridge conditioning. The t1 voltage changes synchronously with the change of the sensor resistance signal.

7. The dual-threshold high-reliability sensor signal acquisition interface protection circuit according to claim 5, characterized in that, In the bridge circuit, resistor R1-2 is an adjustable resistor ranging from 1 to 100 Ω, used to compensate for errors caused by individual differences in the circuit and components, and to ensure the accuracy of data acquisition.

8. The dual-threshold high-reliability sensor signal acquisition interface protection circuit according to claim 6, characterized in that, t1 performs secondary filtering on the parallel capacitor C1-6 to the signal ground SGND, and then the series resistor R1-4 is used for current limiting protection to prevent overcurrent burn-out of the input pin of the subsequent analog switch.

9. The dual-threshold high-reliability sensor signal acquisition interface protection circuit according to claim 6, characterized in that, The dual threshold voltage clamping circuit consists of diodes D1-1 and D1-2; The signal t1_in after two-stage filtering is subjected to dual threshold clamping. t1_in is connected to the positive terminal of diode D1-1, and the negative terminal of D1-1 is connected to +15V. At the same time, t1_in is connected to the negative terminal of diode D1-2, and the positive terminal of D1-2 is connected to -15V. Due to the voltage clamping characteristics of diodes, this circuit limits the voltage range of t1_in to between -15.7V and +15.7V to prevent overvoltage burn-out of the input pins of the subsequent analog switch.

10. The dual-threshold high-reliability sensor signal acquisition interface protection circuit according to claim 9, characterized in that, The t1_in signal, after being current-limited and dual-threshold voltage-limited, is connected to the analog switch U1. The main processor controls the high and low levels of the chip select signal of the analog switch U1 to select the input of multiple analog switches in a time-division multiplexing manner, and outputs reliable sensor signals for subsequent operational amplification and AD conversion.

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