Discrete magnitude differential signal detection circuit for WQAR

Abstract

The utility model discloses a discrete magnitude differential signal detection circuit used for a WQAR. The circuit comprises a comparator which is provided with a V-port, an IN + port, an IN-port, an REF port, an HYST port, a V + port, an OUT port and a GND port. The resistance network is used for detecting discrete magnitude differential signals and providing bias voltage, so that common-mode input signals containing high voltage and negative voltage can work in a low-voltage single-power-supply power supply environment, a comparator with a wide input range and positive and negative voltage dual-power-supply power supply do not need to be used, system design is simplified, and hardware cost is optimized. Through the combination of the resistor network and the common diode electronic component, the lightning stroke energy is limited, so that large-size TVS, SPD and other lightning stroke surge protection devices do not need to be used, the size of the printed circuit board is reduced, and the hardware cost is reduced. Therefore, the interface circuit of the WQAR can work under the condition of single power supply, and the lightning protection requirement can be met.

Description

Technical Field

[0001] This utility model relates to discrete differential signal detection circuits, and in particular to a discrete differential signal detection circuit for WQAR. Background Technology

[0002] Discrete signals, as an important form of information transmission for various onboard sensors, are widely used in avionics systems. They are generally categorized into single-ended signals (GND / OPEN and Supply / OPEN) and differential signals. Differential signals offer advantages such as good anti-interference capabilities and long transmission distances. Existing technical solutions and their drawbacks: 1. Because the common-mode component of differential signals exhibits positive and negative voltages, the detection circuit port must operate within the positive and negative voltage input range. The common practice is to use dual power supplies (positive and negative voltages). However, dual-power supply designs typically increase system complexity and hardware costs, and the mainstream power supply trend in electronic circuits is towards single-power supplies. To meet onboard lightning protection requirements and prevent equipment damage, lightning protection port circuits are designed. Common practices include using TVS (Transient Overvoltage Suppressor) or SPD (Surge Protector) circuits at the equipment port, which typically increases printed circuit board size and hardware costs. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a discrete differential signal detection circuit for WQAR.

[0004] This utility model provides the following technical solution: a discrete differential signal detection circuit for WQAR, including a comparator with a V- port, an IN+ port, an IN- port, a REF port, a HYST port, a V+ port, an OUT port, and a GND port; a first resistor and a second resistor are connected in series at the IN- port, and the other end of the first resistor is connected to a second discrete differential signal; the IN- port is also connected to one end of a third resistor and a fourth resistor; a fifth resistor and a sixth resistor are connected in series at the IN+ port, and the other end of the fifth resistor is connected to a first discrete differential signal; the IN+ port is also connected to one end of a seventh resistor and an eighth resistor; the other end of the third resistor and the other end of the seventh resistor are connected to the positive terminal of the power supply; the other end of the fourth resistor and the other end of the eighth resistor are grounded;

[0005] The IN port is also connected to the negative terminal of the first diode and the positive terminal of the second diode. The positive terminal of the first diode is grounded, and the negative terminal of the second diode is connected to the positive terminal of the power supply.

[0006] The IN+ port is also connected to the negative terminal of the third diode and the positive terminal of the fourth diode. The positive terminal of the third diode is grounded, and the negative terminal of the fourth diode is connected to the positive terminal of the power supply.

[0007] The REF port is connected to the ninth resistor, the ninth resistor is connected to the first capacitor, and the other end of the first capacitor is grounded; the HYST port is connected to the tenth resistor, and the other end of the tenth resistor is grounded; the HYST port is also connected to the eleventh resistor, and the other end of the eleventh resistor is connected to the REF port.

[0008] V-port grounding;

[0009] The V+ port is connected to the positive terminal of the power supply and to the second capacitor. The other end of the second capacitor is grounded.

[0010] The OUT port is connected to the twelfth resistor, and the other end of the twelfth resistor is connected to the base of the transistor. The collector of the transistor outputs the control signal, and the emitter of the transistor is grounded.

[0011] The GND port is grounded and connected to the thirteenth resistor. The other end of the thirteenth resistor is connected to the OUT port.

[0012] Furthermore, the first resistor is 180KΩ, the second resistor is 180KΩ, the third resistor is 20KΩ, the fourth resistor is 20KΩ, the fifth resistor is 180KΩ, the sixth resistor is 180KΩ, the seventh resistor is 20KΩ, the eighth resistor is 20KΩ, the ninth resistor is 430KΩ, the tenth resistor is 2.4MΩ, the eleventh resistor is 10KΩ, the twelfth resistor is 10KΩ, and the thirteenth resistor is 10KΩ.

[0013] Furthermore, the first capacitor is 100nF; the second capacitor is 100nF.

[0014] Furthermore, the power supply voltage is 5V.

[0015] Furthermore, the forward voltage of the first diode, the second diode, the third diode, and the fourth diode is 5V.

[0016] The beneficial effects of this utility model are as follows:

[0017] (1) Enables the WQAR interface circuit to operate under single power supply conditions and meet lightning protection requirements.

[0018] (2) By detecting discrete differential signals through a resistor network and providing bias voltage, common-mode input signals containing high voltage and negative voltage can operate in a low-voltage single power supply environment, thus eliminating the need for a wide input range comparator and dual power supply for positive and negative voltages, simplifying system design and optimizing hardware costs.

[0019] (3) By combining resistor networks and ordinary diode electronic components, the energy of lightning strikes is limited, thus eliminating the need for large-size TVS, SPD and other lightning surge protection devices, reducing the size of printed circuit boards and lowering hardware costs. Attached Figure Description

[0020] Figure 1 This is a circuit diagram of a discrete differential signal detection circuit for WQAR according to the present invention.

[0021] Among them, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13, the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the first capacitor C1, the first capacitor C2, the transistor Q1, the first discrete differential signal INPUT1, the second discrete differential signal INPUT2, the control signal OUTPUT, the power supply VCC, and the ground GND. Detailed Implementation

[0022] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0023] This application uses a resistor network to detect discrete differential signals and provide a bias voltage, enabling common-mode input signals containing high and negative voltages to operate in a low-voltage single-supply environment. This eliminates the need for wide-range comparators and dual positive and negative voltage power supplies, simplifying system design and optimizing hardware costs. Furthermore, by combining resistor networks and common diode components, lightning strike energy is limited, eliminating the need for large-size TVS, SPD, and other surge protection devices, thus reducing printed circuit board size and lowering hardware costs.

[0024] The embodiments of this utility model will be further described below with reference to several examples.

[0025] Example 1

[0026] In this embodiment, the comparator used is an LTC1440IS8.

[0027] like Figure 1A discrete differential signal detection circuit for WQAR includes a comparator with a V- port, an IN+ port, an IN- port, a REF port, a HYST port, a V+ port, an OUT port, and a GND port. A first resistor R1 and a second resistor R2 are connected in series to the IN- port, and the other end of the first resistor R1 is connected to a second discrete differential signal INPUT2. The IN- port is also connected to one end of a third resistor R3 and a fourth resistor R4. A fifth resistor R5 and a sixth resistor R6 are connected in series to the IN+ port, and the other end of the fifth resistor R5 is connected to a first discrete differential signal INPUT1. The IN+ port is also connected to one end of a seventh resistor R7 and an eighth resistor R8. The other ends of the third resistor R3 and the seventh resistor R7 are connected to the positive terminal of the power supply VCC. The other ends of the fourth resistor R4 and the eighth resistor R8 are grounded to GND.

[0028] The IN port is also connected to the negative terminal of the first diode D1 and the positive terminal of the second diode D2. The positive terminal of the first diode D1 is grounded to GND, and the negative terminal of the second diode D2 is connected to the positive terminal of the power supply VCC.

[0029] The IN+ port is also connected to the negative terminal of the third diode D3 and the positive terminal of the fourth diode D4. The positive terminal of the third diode D3 is grounded to GND, and the negative terminal of the fourth diode D4 is connected to the positive terminal of the power supply VCC.

[0030] The REF port is connected to the ninth resistor R9, which is connected to the first capacitor C1. The other end of the first capacitor C1 is grounded to GND. The HYST port is connected to the tenth resistor R10, which is connected to GND. The HYST port is also connected to the eleventh resistor R11, which is connected to the REF port.

[0031] V-port ground GND;

[0032] The V+ port is connected to the positive terminal of the power supply VCC and is connected to the second capacitor C2. The other end of the second capacitor C2 is grounded to GND.

[0033] The OUT port is connected to the twelfth resistor R12, and the other end of the twelfth resistor R12 is connected to the base of transistor Q1. The collector of transistor Q1 outputs the control signal OUTPUT, and the emitter of transistor Q1 is grounded to GND.

[0034] The GND port is grounded and connected to the thirteenth resistor. The other end of the thirteenth resistor is connected to the OUT port.

[0035] In this embodiment, the first resistor R1 to the eighth resistor R8 are all adjustable resistors, and the ninth resistor R9 to the thirteenth resistor R13 are ordinary resistors. Specifically: the first resistor is 180KΩ, the second resistor is 180KΩ, the third resistor is 20KΩ, the fourth resistor is 20KΩ, the fifth resistor is 180KΩ, the sixth resistor is 180KΩ, the seventh resistor is 20KΩ, the eighth resistor is 20KΩ, the ninth resistor is 430KΩ, the tenth resistor is 2.4MΩ, the eleventh resistor is 10KΩ, the twelfth resistor is 10KΩ, and the thirteenth resistor is 10KΩ.

[0036] The first capacitor C1 is 100nF; the second capacitor C2 is 100nF.

[0037] The voltage of the power supply VCC is 5V.

[0038] The forward voltage of the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 is 5V.

[0039] With the above settings, when the voltage of INPUT1 is Vp and the voltage of INPUT2 is Vn, calculate the voltage V(IN+) at the IN+ port and the voltage V(IN-) at the IN- port, as follows:

[0040]

[0041]

[0042] Calculations show that V(IN+) = Vp / 37 + 2.43 and V(IN-) = Vn / 37 + 2.43.

[0043] The detection circuit has a DC bias voltage of approximately 2.43 V, providing a stable DC bias voltage for discrete signals. This allows it to operate in a single-supply environment over a sufficiently wide discrete input range, simplifying circuit design. Simultaneously, the 37:1 conversion ratio provides ample margin for detecting and identifying input signals. The avionics equipment is powered by an AC input voltage of 115 V, equivalent to an DC input voltage of 81.3 V. An adjustable resistor limits the comparator's input signal to its reasonable operating range.

[0044] This embodiment meets the onboard lightning surge protection requirements. Surge voltage is limited by a resistor network R1-R8, and the limited surge voltage is further limited to the power supply voltage range of 0V-5V by diodes D1-D4. Simultaneously, resistors R1-R4 limit the surge current. These voltage-limiting and current-limiting components limit the lightning surge energy, ensuring that the detection circuit is not damaged.

[0045] Assuming the surge voltage is V(T), then the surge voltage V- at the comparator IN- port is:

[0046] V-=(R4 / (R1+R2+R4))×V(T);

[0047] When V- is greater than the power supply potential "5V" or lower than the power supply potential "0V", diode D1 or D2 conducts, clamping the port voltage to the power supply voltage. Similarly, the surge voltage at the comparator's IN+ port can be obtained, ensuring that the detection circuit is not damaged due to overvoltage.

[0048] Meanwhile, resistors R1 and R2 limit the surge current I(T) at the IN port, ensuring that the detection circuit is not damaged due to overcurrent. Specifically:

[0049] I(T) = (V(T) - 5V) / (R1 + R2);

[0050] Similarly, the surge current at the comparator's IN+ port can be obtained, ensuring that the detection circuit will not be damaged due to overcurrent.

[0051] In addition, the comparator has two voltage input terminals IN+ and IN- and one output terminal OUT. When the IN+ voltage is higher than the IN- voltage, the output is high and Q1 is turned on. When the IN+ voltage is lower than the IN- voltage, the output is low and Q1 is turned off.

[0052] This application enables the WQAR interface circuit to operate under single power supply conditions and meet lightning protection requirements.

[0053] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A discrete differential signal detection circuit for WQAR, comprising a comparator having a V- port, an IN+ port, an IN- port, a REF port, a HYST port, a V+ port, an OUT port, and a GND port, characterized in that, The first and second resistors are connected in series at the IN- port. The other end of the first resistor is connected to the second discrete differential signal. The IN- port is also connected to one end of the third and fourth resistors. The fifth and sixth resistors are connected in series at the IN+ port. The other end of the fifth resistor is connected to the first discrete differential signal. The IN+ port is also connected to one end of the seventh and eighth resistors. The other ends of the third and seventh resistors are connected to the positive terminal of the power supply. The other ends of the fourth and eighth resistors are grounded. The IN port is also connected to the negative terminal of the first diode and the positive terminal of the second diode. The positive terminal of the first diode is grounded, and the negative terminal of the second diode is connected to the positive terminal of the power supply. The IN+ port is also connected to the negative terminal of the third diode and the positive terminal of the fourth diode. The positive terminal of the third diode is grounded, and the negative terminal of the fourth diode is connected to the positive terminal of the power supply. The REF port is connected to the ninth resistor, the ninth resistor is connected to the first capacitor, and the other end of the first capacitor is grounded; the HYST port is connected to the tenth resistor, and the other end of the tenth resistor is grounded; the HYST port is also connected to the eleventh resistor, and the other end of the eleventh resistor is connected to the REF port. V-port grounding; The V+ port is connected to the positive terminal of the power supply and to the second capacitor, with the other end of the second capacitor grounded. The OUT port is connected to the twelfth resistor, and the other end of the twelfth resistor is connected to the base of the transistor. The collector of the transistor outputs the control signal, and the emitter of the transistor is grounded. The GND port is grounded and connected to the thirteenth resistor. The other end of the thirteenth resistor is connected to the OUT port.

2. The discrete differential signal detection circuit for WQAR according to claim 1, characterized in that, The first resistor is 180KΩ, the second resistor is 180KΩ, the third resistor is 20KΩ, the fourth resistor is 20KΩ, the fifth resistor is 180KΩ, the sixth resistor is 180KΩ, the seventh resistor is 20KΩ, the eighth resistor is 20KΩ, the ninth resistor is 430KΩ, the tenth resistor is 2.4MΩ, the eleventh resistor is 10KΩ, the twelfth resistor is 10KΩ, and the thirteenth resistor is 10KΩ.

3. The discrete differential signal detection circuit for WQAR according to claim 1, characterized in that, The first capacitor is 100nF; the second capacitor is 100nF.

4. The discrete differential signal detection circuit for WQAR according to claim 1, characterized in that, The power supply voltage is 5V.

5. The discrete differential signal detection circuit for WQAR according to claim 1, characterized in that, The forward voltage of the first diode, the second diode, the third diode, and the fourth diode is 5V.

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