An on-board probe warming detection circuit

Abstract

The application provides an airborne probe warming detection circuit, and belongs to the technical field of airborne probe warming detection, and specifically comprises a current detection circuit, a half-wave rectification circuit, an amplification circuit and a discrete quantity output circuit; the current detection circuit is used for detecting the current of the airborne probe warming circuit and outputting a warming current signal, the half-wave rectification circuit is used for filtering the warming current signal into a direct current voltage signal waveform, the amplification circuit is used for amplifying the direct current voltage signal output by the half-wave rectification circuit to obtain an ideal voltage signal, and the discrete quantity output circuit is used for converting the final voltage signal into a discrete quantity signal and then outputting the discrete quantity signal to a superior device; the current detection circuit is an alternating current transformer. The detection circuit can cover the warming current detection of the mainstream airborne probe heating materials at present, can reduce the basic failure rate, reduce the product power consumption, shorten the research and development cycle, and realize the warming detection and result output in a pure hardware mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of airborne probe heating detection, in particular to an airborne probe heating detection circuit. BACKGROUND

[0002] At present, the main method for airborne probe (PTC) heating detection is software + Hall sensor current detection. This testing method has high power consumption, high basic failure rate and long development time, and requires software / hardware cooperation. The Hall sensor itself has a large range and low precision, and a high precision and small range, which limits the use range of the Hall sensor.

[0003] There is no pure hardware implementation heating current detection and output circuit design suitable for various airborne probe armored heating wires, MCHs and PTCs in the existing market. This situation may mislead pilots into thinking that the airborne sensor is working normally, but in fact, different degrees of icing blockage may have occurred, which will affect the collection and output of key information such as aircraft airspeed and altitude, and cause catastrophic effects on the aircraft. SUMMARY

[0004] Therefore, the present application provides an airborne probe heating detection circuit, which solves the problems in the prior art, can cover the heating current detection of the current mainstream airborne probe heating materials, and can reduce the basic failure rate, reduce product power consumption, shorten the development cycle, and realize heating detection and result output by pure hardware.

[0005] The airborne probe heating detection circuit provided by the present application adopts the following technical solution:

[0006] An airborne probe heating detection circuit, comprising a current detection circuit, a half-wave rectification circuit, an amplification circuit and a discrete quantity output circuit.

[0007] The current detection circuit is used to detect the current of the airborne probe heating circuit and output a heating current signal, the output end of the current detection circuit and the half-wave rectification circuit are electrically connected, the half-wave rectification circuit is used to filter the heating current signal into a direct current voltage signal waveform, the output end of the half-wave rectification circuit and the amplification circuit are electrically connected, the amplification circuit is used to amplify the direct current voltage signal output by the half-wave rectification circuit to obtain an ideal voltage signal, and the discrete quantity output circuit is used to convert the final voltage signal into a discrete quantity signal and then output to a superior device.

[0008] The current detection circuit is an alternating current transformer.

[0009] Optionally, the current detection circuit comprises a primary coil and a secondary coil, two ends of the primary coil are connected to the on-board probe heating circuit, when the on-board probe heating circuit has current flowing therethrough, the current passes through the primary coil, the secondary coil generates an induced current, and two ends of the secondary coil are electrically connected to an input end of a half-wave rectification circuit.

[0010] Optionally, the half-wave rectification circuit comprises a rectification diode V101, a capacitor C108 and a resistor R108 connected in parallel, a cathode of the rectification diode V101 is connected to one end of the secondary coil, an anode of the diode V101, a negative electrode of the capacitor C108 and one end of the resistor R108 are electrically connected, the other end of the secondary coil, a positive electrode of the capacitor C108 and the other end of the resistor R108 are electrically connected, and two ends of the resistor R108 serve as output ends of the half-wave rectification circuit and are electrically connected to input ends of an amplification circuit.

[0011] Optionally, the amplification circuit comprises an instrument amplifier, a positive sampling voltage input end of the instrument amplifier is electrically connected to one end of the resistor R108, a negative sampling voltage input end of the instrument amplifier is electrically connected to the other end of the resistor R108, an amplification resistor R143 is connected in series between two RG pins of the instrument amplifier, a positive power supply +VS pin of the instrument amplifier is connected to a positive electrode of a power supply, a negative power supply -VS pin of the instrument amplifier is connected to a negative electrode of the power supply, a REF pin of the instrument amplifier is grounded, and an output end OUT pin of the instrument amplifier serves as an output end of the amplification circuit.

[0012] Optionally, a power supply voltage of the instrument amplifier is 15V.

[0013] Optionally, the on-board probe heating detection circuit further comprises a follow-up circuit and a voltage stabilizing circuit, an input end of the follow-up circuit is electrically connected to an output end of the amplification circuit through a resistor R136, an output end of the follow-up circuit is electrically connected to an input end of the voltage stabilizing circuit, and an output end of the voltage stabilizing circuit is electrically connected to an input end of a discrete quantity output circuit.

[0014] Optionally, the voltage stabilizing circuit comprises a voltage stabilizing diode, the discrete quantity output circuit comprises an optical coupler, an output end of the follow-up circuit and an input end of the voltage stabilizing circuit are electrically connected through a resistor R213, one end of the resistor R213 is electrically connected to the output end of the follow-up circuit, the other end of the resistor R213 is electrically connected to an anode of a light-emitting diode of the input end of the optical coupler, a cathode of the light-emitting diode of the input end of the optical coupler is grounded, the anode of the light-emitting diode of the input end of the optical coupler is electrically connected to a cathode of the voltage stabilizing diode, an anode of the voltage stabilizing diode is grounded, and after the voltage output by the follow-up circuit is input into the input end of the optical coupler, the light-emitting diode and a photosensitive element inside the optical coupler are triggered to work, the output end of the optical coupler is turned on, and a discrete quantity output signal is triggered.

[0015] In summary, the present application includes the following beneficial technical effects:

[0016] The present application realizes the correct collection of the heating current of the armored heating wire, MCH and PTC material, and the circuit design uses pure hardware to realize the current collection and the output function of the heating state. Since the CPU processor and its peripheral circuit are not used, the basic failure rate is reduced, the product power consumption is reduced, and the research and development cycle is shortened.

[0017] The heating detection circuit design of the present application realizes the breakthrough of large range, high precision heating current detection combined with low basic failure rate and low product power consumption design, and applies pure hardware circuit to realize large range, high precision heating current detection and heating state output function. The demand design from probe heating detection to state reporting is completely realized. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0019] Figure 1 The principle block diagram of the on-board probe heating detection circuit of the present application;

[0020] Figure 2 The schematic diagram of the heating detection circuit and the half-wave rectification circuit of the present application;

[0021] Figure 3 The schematic diagram of the amplification circuit and the following circuit of the present application;

[0022] Figure 4 The schematic diagram of the voltage stabilizing circuit and the discrete quantity output circuit of the present application DETAILED DESCRIPTION

[0023] The embodiments of the present application will be described in detail below with reference to the drawings.

[0024] Following embodiments of the present application are illustrated by way of specific examples, and other advantages and effects of the present application will be readily understood by those skilled in the art from the disclosure. Obviously, the described embodiments are only a part of embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied by other different specific embodiments, and various modifications or changes can be made to the details based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0025] It should be noted that various aspects of the embodiments described below are within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms and that any specific structure and / or function described herein is merely illustrative. Based on the teachings herein one skilled in the art should appreciate that an aspect described herein can be implemented independently of any other aspects and that an aspect can be implemented both as any number of software running on a device and / or as an apparatus manufactured for a particular purpose. For example, an aspect can be implemented as a software routine running on a general purpose computer or be implemented as a hardware device, such as an application- specific integrated circuit ("ASIC") or a field-programmable gate array ("FPGA"). An aspect can be any combination of software and / or hardware.

[0026] It should also be noted that the figures provided in the following embodiments are only to illustrate the basic concept of the present application in a schematic manner, and only the components related to the present application are shown in the figures, not drawn according to the number, shape and size of the components when actually implemented, and the shape, number and proportion of each component when actually implemented can be a random change, and the layout pattern of the components can also be more complex.

[0027] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, one skilled in the art will understand that the described aspects can be practiced without these specific details.

[0028] The current airborne probe (total pressure sensor, static pressure sensor, angle of attack sensor, total temperature sensor) is electrically heated, and the heating detection principle is to detect the current by using a closed loop circuit. If the heating circuit is open, the current cannot be detected. That is, when it is detected that there is current in the heating circuit, the heating circuit is normal, and current flows through the heating element. That is, the airborne probe is normal, and further plays a role in the form of electric heating to prevent the airborne probe from icing, so that it works normally, collects atmospheric parameters such as atmospheric pressure, atmospheric temperature and angle of attack, and ensures the safety of the aircraft.

[0029] With the development of heating technology, people's demand for constant power heating is increasing. In view of the performance of PTC material in heating, it is gradually developed and applied to airborne probes. PTC is a positive temperature coefficient thermistor. Below the Curie temperature, the PTC thermistor has a small resistance value, and when the temperature exceeds the Curie temperature, the resistance value will increase by tens of times, hundreds of times, or even thousands of times. The sharp change of the resistance value directly leads to a huge change in the current under the condition that the voltage is constant, resulting in a large span of the heating current detection and high precision requirements. After reaching the Curie temperature, the current of a certain type of airborne probe is 0.5A, and before reaching the Curie temperature, the current reaches 15A. Therefore, the heating current detection circuit needs to cover the entire current range while meeting the high precision requirements, so as to effectively and correctly judge the heating state of the probe and prevent false reporting of the heating state of the airborne probe.

[0030] The embodiment of the present application provides a heating detection circuit for an airborne probe.

[0031] As shown in Figure 1 , a heating detection circuit for an airborne probe includes a current detection circuit, a half-wave rectification circuit, an amplification circuit, and a discrete quantity output circuit.

[0032] The current detection circuit is used to detect the current of the heating circuit of the airborne probe and output a heating current signal. The half-wave rectification circuit and the output end of the current detection circuit are electrically connected. The half-wave rectification circuit is used to filter the heating current signal into a direct current voltage signal waveform. The amplification circuit and the output end of the half-wave rectification circuit are electrically connected. The amplification circuit is used to amplify the direct current voltage signal output by the half-wave rectification circuit to obtain an ideal voltage signal. The discrete quantity output circuit is used to convert the final voltage signal into a discrete quantity signal and output it to a superior device. The current detection circuit is an alternating current transformer.

[0033] The amplification circuit sets a corresponding amplification coefficient according to the current characteristics of the airborne probe connected to the heating circuit of the airborne probe to obtain a final current signal. Specifically, the airborne probe includes a total pressure sensor, a static pressure sensor, an angle of attack sensor, and a total temperature sensor.

[0034] As shown in Figure 2 , the current detection circuit includes a primary coil and a secondary coil. The two ends of the primary coil are connected to the heating circuit of the airborne probe. When the heating circuit of the airborne probe has a current flowing through it, the current passes through the primary coil, and the secondary coil generates an induced current. The two ends of the secondary coil are electrically connected to the input end of the half-wave rectification circuit.

[0035] The current detection circuit of the application adopts an AC transformer: the collection principle of the AC transformer is a scaled-down ratio of a primary coil and a secondary coil, for example, collecting 1A current, taking an AC transformer with a turns ratio of 1000:1 as an example, converting 1A AC into 1mA AC power, and then matching a resistance, at the same time, collecting the voltage value on the resistance, amplifying the voltage, and taking it as the excitation of the heating state output. The heating state of the on-board probe is sent out through the rear-end circuit.

[0036] As shown in Figure 2 , the half-wave rectifier circuit comprises a rectifier diode V101 and a capacitor C108 and a resistor R108 connected in parallel, one end of the cathode of the rectifier diode V101 is connected with the secondary coil, the anode of the diode V101, the negative electrode of the capacitor C108 and one end of the resistor R108 are electrically connected, the other end of the secondary coil, the positive electrode of the capacitor C108 and the other end of the resistor R108 are electrically connected, and the two ends of the resistor R108 are used as the output end of the half-wave rectifier circuit and are electrically connected with the input end of the amplification circuit.

[0037] According to the coil ratio of the AC transformer itself, an induced current of 1 / 1000 of the original current is obtained. Through the rectifier diode V101, the capacitor C108 and the matching resistor R108, according to the unidirectional conduction of the rectifier diode and the participation of the capacitive device, a DC-like voltage is formed across the resistor, and the voltage across the resistor is V=I*R.

[0038] As shown in Figure 3 , the amplification circuit comprises an instrument amplifier, the positive electrode of the sampling voltage input end of the instrument amplifier is electrically connected with the positive electrode of the resistor R108, the negative electrode of the sampling voltage input end of the instrument amplifier is electrically connected with the negative electrode of the resistor R108, an amplification resistor R143 is connected in series between the two RG pins of the instrument amplifier, the positive electrode +VS pin of the power supply of the instrument amplifier is connected with the positive electrode of the power supply, the negative electrode -VS pin of the power supply of the instrument amplifier is connected with the negative electrode of the power supply, the REF pin of the instrument amplifier is grounded, and the output end OUT pin of the instrument amplifier is used as the output end of the amplification circuit.

[0039] The power supply voltage of the instrument amplifier is 15V.

[0040] The on-board probe heating detection circuit further comprises a follower circuit and a voltage stabilizing circuit, the input end of the follower circuit is electrically connected with the output end of the amplification circuit through a resistor R136, the output end of the follower circuit is electrically connected with the input end of the voltage stabilizing circuit, and the output end of the voltage stabilizing circuit is electrically connected with the input end of the discrete quantity output circuit.

[0041] After obtaining the voltages V+ and V- across the resistor R108, they are connected to the 3-pin and 2-pin of the instrument amplifier N101 according to The voltage amplification is achieved by adjusting the resistance value of the amplification resistor R143 to obtain the expected voltage amplification. The amplified voltage is connected to the 2nd pin and the 3rd pin of the follow-up circuit U101A, and the voltage is output through the 1st pin after being followed and isolated.

[0042] In the embodiment of the present application, the amplification circuit uses an operational amplifier to achieve the voltage amplification function, and the operational amplifier is used as the follow-up circuit in the embodiment of the present application

[0043] As shown in Figure 4 , the voltage stabilizing circuit includes a voltage stabilizing diode V232, the discrete quantity output circuit includes an optocoupler, the output end of the follow-up circuit and the input end of the voltage stabilizing circuit are electrically connected through a resistor R213, one end of the resistor R213 is electrically connected with the output end of the follow-up circuit, the other end of the resistor R213 is electrically connected with the anode of the light emitting diode of the input end of the optocoupler, the cathode of the light emitting diode of the input end of the optocoupler is grounded, the anode of the light emitting diode of the input end of the optocoupler is electrically connected with the cathode of the voltage stabilizing diode, the anode of the voltage stabilizing diode is grounded, after the voltage output by the follow-up circuit is connected to the input end of the optocoupler, the light emitting diode and the photosensitive element inside the optocoupler are triggered to work, the output end of the optocoupler is turned on to trigger the discrete quantity output signal.

[0044] The amplified voltage value in the present application is related to the current value on the left side of the optocoupler in the rear end, that is, the amplified voltage value is used in cooperation with the rear-end voltage dividing resistor to ensure that the current flowing through the left end of the optocoupler is within the range of 5mA-10mA.

[0045] After the amplified voltage is obtained, the voltage stabilizing diode V232 is configured to stabilize the voltage at about 3.3V to protect the rear-end optocoupler H202, and the voltage signal is connected to the 1st pin of the optocoupler H202 to trigger the light emitting diode and the transistor inside the optocoupler to work, turn on the 15th pin and the 16th pin of the optocoupler, and then trigger the discrete quantity output signal, that is, the suspended / grounded, grounded effective signal, to transmit the warming effective signal to the upper-level device.

[0046] The present application uses an alternating current transformer as a current detection element, which can break through the range limitation of the Hall sensor. The precision of the Hall sensor on the market is only 0.2V / A for the 10A range, and the precision is 0.8V / A for the 5A range. The current of the airborne probe made of PTC material can be as high as 15A, and the current is only 0.3A after reaching the Curie temperature point. The current range and precision of the current Hall sensor cannot be considered. According to the formula and precision calculation: V=2.5±X*I P , X is the inherent precision of the chip, that is, 0.2 or 0.8. When a large range is selected, X is 0.2, and when the current is 0.3A, the product of the two is 0.06, V=2.56, which is only 0.06V different from the voltage reference 2.5V when there is no current. The signal is extremely small and is basically submerged in signal noise, and cannot correctly reflect the warming state of the airborne probe.

[0047] The application designs a combination of an alternating current transformer, an operational amplifier and a voltage stabilizing circuit, breaks through the above range and precision limit, and the amplification coefficient can be adjusted according to the collected voltage signal to ensure that the input current range of the left end of the optocoupler is 5mA-10Ma. The voltage stabilizing circuit can play a voltage stabilizing role in the large current stage before the PTC material reaches the Curie temperature point to protect the rear-end circuit safety and the input current value of the left end of the optocoupler, ensure the accuracy of the collected heating signal, and can report the heating state of the airborne probe in real time.

[0048] The application reports discrete quantity signals to the superior equipment through the optocoupler. The whole airborne probe heating detection and state reporting function is realized.

[0049] The above is only a specific embodiment of the application, but the protection scope of the application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. An on-board probe warm-up detection circuit, comprising: The current detection circuit, the half-wave rectification circuit, the amplification circuit and the discrete quantity output circuit are included. The current detection circuit is used for detecting the current of the on-board probe warming circuit and outputting a warming current signal, the output end of the current detection circuit is electrically connected with the half-wave rectification circuit, the half-wave rectification circuit is used for filtering the warming current signal into a direct current voltage signal, the output end of the half-wave rectification circuit is electrically connected with the amplification circuit, the amplification circuit is used for amplifying the direct current voltage signal output by the half-wave rectification circuit to obtain an ideal voltage signal, and the discrete quantity output circuit is used for converting the final voltage signal into a discrete quantity signal and then outputting the discrete quantity signal to a superior device. The current detection circuit is an alternating current transformer. The current detection circuit includes a primary coil and a secondary coil, two ends of the primary coil are connected with the on-board probe warming circuit, when the on-board probe warming circuit has current flowing therethrough, the current passes through the primary coil, and the secondary coil generates an induced current, and two ends of the secondary coil are electrically connected with the input end of the half-wave rectification circuit. The half-wave rectification circuit includes a rectifier diode V101, a capacitor C108 and a resistor R108 connected in parallel, one end of the secondary coil and the cathode of the rectifier diode V101 are connected, the anode of the diode V101, the negative electrode of the capacitor C108 and one end of the resistor R108 are electrically connected, the other end of the secondary coil, the positive electrode of the capacitor C108 and the other end of the resistor R108 are electrically connected, and the two ends of the resistor R108 are used as the output end of the half-wave rectification circuit and are electrically connected with the input end of the amplification circuit. The amplification circuit includes an instrument amplifier, the positive electrode of the sampling voltage input end of the instrument amplifier is electrically connected with one end of the resistor R108, the negative electrode of the sampling voltage input end of the instrument amplifier is electrically connected with the other end of the resistor R108, an amplification resistor R143 is connected in series between the two RG pins of the instrument amplifier, the positive electrode +VS pin of the instrument amplifier is connected with the positive electrode of the power supply, the negative electrode -VS pin of the instrument amplifier is connected with the negative electrode of the power supply, the REF pin of the instrument amplifier is grounded, and the output end OUT pin of the instrument amplifier is used as the output end of the amplification circuit.

2. The on-board probe warm-up detection circuit of claim 1, wherein, The power supply voltage of the instrument amplifier is 15V.

3. The on-board probe warm-up detection circuit of claim 1, wherein, The on-board probe warming detection circuit further includes a follower circuit and a voltage stabilizing circuit, the input end of the follower circuit is electrically connected with the output end of the amplification circuit through the resistor R136, the output end of the follower circuit is electrically connected with the input end of the voltage stabilizing circuit, and the output end of the voltage stabilizing circuit is electrically connected with the input end of the discrete quantity output circuit.

4. The on-board probe warm-up detection circuit of claim 3, wherein, The voltage stabilizing circuit comprises a voltage stabilizing diode, the discrete quantity output circuit comprises an optical coupler, the output end of the follow-up circuit and the input end of the voltage stabilizing circuit are electrically connected through a resistor R213, one end of the resistor R213 is electrically connected with the output end of the follow-up circuit, the other end of the resistor R213 is electrically connected with the anode of the light emitting diode of the input end of the optical coupler, the cathode of the light emitting diode of the input end of the optical coupler is grounded, the anode of the light emitting diode of the input end of the optical coupler is electrically connected with the cathode of the voltage stabilizing diode, and the anode of the voltage stabilizing diode is grounded. After the voltage output by the follow-up circuit is input into the input end of the optical coupler, the light emitting diode and the photosensitive element inside the optical coupler are triggered to work, the output end of the optical coupler is turned on, and the discrete quantity output signal is triggered.

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