Device door signal detection circuit and apparatus

Abstract

The application discloses a device door signal detection circuit and device, including first detection branch, second detection branch and door state signal output branch, the signal output end of first detection branch is connected with door sensor, and the first switch tube is controlled based on the potential state of the signal output end; the power supply backflow end of second detection branch is connected with door sensor, and the second switch tube is controlled based on whether the power supply backflow end outputs backflow current; the door state signal output branch includes photoelectric coupler, first switch tube and second switch tube, the anode input end of photoelectric coupler is connected with external power supply, and the cathode input end is connected with ground through the series connection of first switch tube and second switch tube; wherein, when the first switch tube and the second switch tube are both turned on, the door state signal output branch outputs first level signal; when at least one of the first switch tube and the second switch tube is turned off, the door state signal output branch outputs second level signal; the first level signal and the second level signal represent different door states.

Description

Technical Field

[0001] This application relates to the field of detection circuit technology, and in particular to a device gate signal detection circuit and apparatus. Background Technology

[0002] In industrial automation equipment, accurate detection of door status signals is crucial for ensuring safe operation. Most related technologies use normally open or normally closed sensors to detect door status. However, current door detection circuits can only simply determine whether the door is open or closed. They cannot accurately determine this when the sensor malfunctions, leading to misjudgments and posing serious safety hazards. Summary of the Invention

[0003] The purpose of this application is to at least solve one of the technical problems existing in the prior art, and to provide a device gate signal detection circuit and apparatus that can realize multi-channel high voltage parallel testing and improve the efficiency of wafer testing.

[0004] In a first aspect, embodiments of this application provide a device gate signal detection circuit, including: The first detection branch is used to connect to the signal output terminal of the door sensor and control the on / off state of the first switching transistor based on the potential state of the signal output terminal. The second detection branch is used to connect to the power supply return terminal of the door sensor and control the on / off state of the second switching transistor based on whether the power supply return terminal outputs return current. The gate status signal output branch includes an optocoupler, a first switch, and a second switch. The anode input terminal of the optocoupler is connected to an external power supply, and the cathode input terminal is grounded through the first switch and the second switch connected in series. Specifically, when both the first and second switching transistors are turned on, the optocoupler operates, and the gate status signal output branch outputs a first-level signal; when at least one of the first and second switching transistors is turned off, the optocoupler stops operating, and the gate status signal output branch outputs a second-level signal; the first-level signal and the second-level signal represent different gate states.

[0005] In the device door signal detection circuit of this application embodiment, the second detection branch includes a second operational amplifier and a sampling resistor. One end of the sampling resistor is connected to the power supply return terminal of the door sensor, and the other end is grounded. The positive input terminal and the negative input terminal of the second operational amplifier are coupled to the two ends of the sampling resistor through a resistor network. The output terminal of the second operational amplifier is connected to the control terminal of the second switching transistor.

[0006] In the device gate signal detection circuit of this application embodiment, the second detection branch further includes a first voltage divider resistor, a second voltage divider resistor, a third input resistor, and a fourth feedback resistor. One end of the sampling resistor is connected to the positive input terminal of the second operational amplifier through the first voltage divider resistor, and the second voltage divider resistor is connected between the positive input terminal of the second operational amplifier and ground. The other end of the sampling resistor is connected to the negative input terminal of the second operational amplifier through the third input resistor, and the fourth feedback resistor is connected between the output terminal and the negative input terminal of the second operational amplifier.

[0007] In the device door signal detection circuit of this application embodiment, the first detection branch includes a first operational amplifier and a fifth pull-up resistor. The positive input terminal of the first operational amplifier is connected to the first reference power supply through the fifth pull-up resistor, and is also connected to the signal output terminal of the door sensor. The negative input terminal of the first operational amplifier is short-circuited with the output terminal, and the output terminal of the first operational amplifier is connected to the control terminal of the first switching transistor.

[0008] In the device gate signal detection circuit of this application embodiment, the first detection branch further includes a first filter capacitor. One end of the first filter capacitor is connected to the connection point between the signal output terminal and the fifth pull-up resistor, and the other end of the first filter capacitor is grounded.

[0009] In the device door signal detection circuit of this application embodiment, when the device door is closed, the signal output terminal of the door sensor is in a floating high-impedance state, and the first detection branch controls the first switch to be turned on; when the device door is open, the signal output terminal is in a grounded state, and the first detection branch controls the first switch to be turned off.

[0010] In the device door signal detection circuit of this application embodiment, the first detection branch further includes an inverter. The input terminal of the inverter is connected to the signal output terminal, and the output terminal of the inverter is connected to the control terminal of the first switching transistor. When the device door is closed, the signal output terminal is in a grounded state, and the first detection branch controls the first switching transistor to be turned on. When the device door is open, the signal output terminal is in a floating high-impedance state, and the first detection branch controls the first switching transistor to be turned off.

[0011] In the device gate signal detection circuit of this application embodiment, the first detection branch includes a first operational amplifier, a fifth pull-up resistor, a sixth input resistor, and a seventh feedback resistor. One end of the fifth pull-up resistor is connected to a first reference power supply, and the other end is connected to a signal output terminal. The negative input terminal of the first operational amplifier is connected to the signal output terminal through the sixth input resistor. The output terminal of the first operational amplifier is connected to the negative input terminal of the first operational amplifier through the seventh feedback resistor. The positive input terminal of the first operational amplifier is connected to a second reference power supply.

[0012] In the device door signal detection circuit of this application embodiment, the door state signal output branch further includes a door state filter resistor and a door state filter capacitor. The output terminal of the optocoupler is connected to one end of the door state filter resistor, the other end of the door state filter resistor serves as a signal output node, and the door state filter capacitor is connected between the signal output node and ground.

[0013] Secondly, this application also proposes a device door signal detection device, including a door sensor and the aforementioned device door signal detection circuit. The door sensor includes a power supply input terminal for connecting to an external power source, a power supply return terminal for outputting return current, and a signal output terminal for switching potential states based on the switching state of the device door.

[0014] The device gate signal detection circuit and apparatus provided in the embodiments of this application have at least the following beneficial effects: The wafer test socket isolates multiple first driving terminals and multiple first return terminals, thereby enabling the application of signals to the electrodes of each device under test on the wafer and returning them through independent first return terminals, realizing multi-channel parallel testing; the test module provides an independent isolated power supply for each wafer test unit, ensuring that each channel is not affected by the power of other channels, allowing the floating terminal of each channel to float freely to different potentials relative to ground, and the first return terminal and the second return terminal are connected to a common potential terminal, forming a current return loop shared by all channels, so that any common-mode voltage change on any channel will be forced to the same reference, effectively suppressing common-mode interference; the switch matrix can connect multiple high-voltage signals of the test module to the corresponding first driving terminals on the wafer test socket as needed, thereby allowing the limited test channels of the test module to cover more devices under test in a time-division manner through the switch matrix. When the first return terminal and the second return terminal are connected to a common potential terminal, the connection relationship between the first driving terminal and the second driving terminal can be switched by the switch matrix, thereby realizing channel switching without manual rewiring, effectively improving test efficiency.

[0015] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0016] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0017] The present application will be further described below with reference to the accompanying drawings and embodiments; Figure 1This is a schematic diagram of the structure of a device gate signal detection circuit provided in one embodiment of this application; Figure 2 This is a schematic diagram of the specific connection of a device gate signal detection circuit provided in one embodiment of this application. Detailed Implementation

[0018] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0019] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship according to the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0020] In the description of this application, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0021] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0022] In industrial automation equipment, accurate detection of door status signals is crucial for ensuring safe operation. However, existing technologies have limitations in door status detection. For example, normally closed sensors may appear suspended when the door is closed or the sensor is disconnected, making it difficult for traditional single-channel detection circuits to accurately distinguish between these two situations. This can lead to system misjudgments and potential safety risks. Furthermore, current circuits lack compatibility with different types of sensors and lack independent monitoring capabilities for sensor connection status, making real-time anomaly diagnosis difficult.

[0023] The various embodiments of the device gate signal detection circuit of this application will be further described below with reference to the accompanying drawings.

[0024] Reference Figure 1 and Figure 2 , Figure 1This is a schematic diagram of the structure of a device gate signal detection circuit provided in one embodiment of this application. Figure 2 This is a schematic diagram of the specific connection of a device door signal detection circuit provided in one embodiment of this application. It can be understood that the device door signal detection circuit is an electronic circuit used to monitor the open / closed state of a device door. It receives the signal generated by the door sensor J1 and converts it into a level signal that the system can recognize, indicating the current state of the device door. The door sensor J1 is a sensing element installed on the device door, capable of detecting the open or closed state of the door and outputting a corresponding electrical signal. Specifically, the door sensor J1 may include three pins: a power supply input terminal 8, a power supply return terminal 9, and a signal output terminal 4, such as... Figure 1As shown, the power input terminal 8 is used to connect to the positive terminal of an external power supply, such as +24V, to power the internal circuit of the door sensor J1. The power return terminal 9 is the return path of the internal current of the door sensor J1, which is usually connected to the system ground GND. In this embodiment, the power return terminal 9 is connected to the second detection branch to detect whether there is a return current and whether the current threshold of the return current meets the standard, thereby determining whether the door sensor J1 is online and effective. For example, when the door sensor J1 is normally connected, there is always a current of 5mA to 7.5mA, and when the door sensor J1 is abnormal, the current is zero. The signal output terminal 4 is the output terminal of the door sensor J1, which is grounded or left floating through an internal switch to reflect the opening and closing status of the device door. The internal circuit of the gate sensor J1 may include a first switch, a second switch, a sensor switch transistor, a collector resistor, a base current limiting resistor, and a base pull-down resistor. One end of the first switch is connected to a reference power supply, and the other end is connected to the base of the sensor switch transistor through the base current limiting resistor. One end of the second switch is connected to the node between the first switch and the base current limiting resistor, and the other end is connected to the power supply return terminal 9. One end of the base pull-down resistor is connected to the node between the base current limiting resistor and the base of the switch transistor, and the other end is connected to the power supply return terminal 9. The collector of the sensor switch transistor is connected to the signal output terminal 4 through the collector resistor, and the emitter is connected to the power supply return terminal 9. Therefore, when the sensor switch transistor is turned on, the potential of the signal output terminal 4 is pulled down to near ground, i.e., it is in a grounded state. When the sensor switch transistor is turned off, the signal output terminal 4 is in a floating high-resistance state. The door sensor J1 can be a normally open, normally closed, or sensor with a specific signal output mode. If the door sensor J1 is normally closed, when the equipment door is closed, the first switch is open and the second switch is closed. At this time, the base potential of the sensor switch transistor is pulled low, the sensor switch transistor is cut off, and the signal output terminal 4 is in a floating high-resistance state. When the equipment door is open, the first switch is closed and the second switch is open. The base potential of the sensor switch transistor is pulled high, the sensor switch transistor is turned on, and the signal output terminal 4 is in a grounded state. If the door sensor J1 is normally open, when the equipment door is closed, the first switch is closed and the second switch is open. The sensor switch transistor is turned on, and the signal output terminal 4 is in a grounded state. When the equipment door is open, the first switch is open and the second switch is closed. The sensor switch transistor is cut off, and the signal output terminal 4 is in a floating high-resistance state.

[0025] The equipment door signal detection circuit includes a first detection branch, a second detection branch, and a door status signal output branch. The first detection branch is the circuit part used to process the potential state of the signal output terminal 4 of the door sensor J1, determine the actual opening and closing state of the equipment door, and switch the control signal of the first switch transistor MQ1 in the door status signal output branch based on the potential state of the signal output terminal 4 of the door sensor J1. Specifically, the first detection branch identifies and processes the potential state of the signal output terminal 4 of the door sensor J1 through internal circuitry, and then outputs a level control signal. This level control signal is used to drive the first switch transistor MQ1 to turn on or off. For example, the first detection branch can be a simple comparator circuit that compares the potential of the signal output terminal 4 with a preset reference potential and outputs a high level or low level according to the comparison result to control the first switch transistor MQ1. Assuming it is a normally closed door sensor J1, when the equipment door is closed, the signal output terminal 4 of the door sensor J1 is in a floating high-impedance state, then the first detection branch controls the first switch transistor MQ1 to turn on. When the equipment door is open, the signal output terminal 4 is in a grounded state, and the first switch transistor MQ1 is off.

[0026] The second detection branch is used to indirectly detect the connection status of the door sensor J1, such as abnormal states like disconnection or non-connection. The second detection branch can sample the return current at the power supply return terminal 9 of the door sensor J1 to determine if the door sensor J1 is normally online, and based on this, control the on / off state of the second switch MQ2. Specifically, when the door sensor J1 is normally connected, there is always current at the power supply return terminal 9. When the second detection branch detects a normal return current, it outputs a level control signal to turn on the second switch MQ2. When the door sensor J1 is disconnected or not connected, the return current at the power supply return terminal 9 is zero, and the second detection branch outputs another level control signal to turn off the second switch MQ2. For example, the second detection branch can use a current detection circuit to convert the return current into a voltage signal, and then use a threshold judgment circuit to control the second switch MQ2.

[0027] The gate status signal output branch includes a first switch MQ1, a second switch MQ2, and an optocoupler. Since the on / off states of the first and second switches MQ1 and MQ2 are controlled by the first and second detection branches respectively, the first and second detection branches jointly control the operating state of the gate status signal output branch. This branch then integrates the detection results from the first and second detection branches and outputs a level signal representing the gate status. The anode input of the optocoupler is connected to an external power supply through a protection resistor R10, and the cathode input is grounded through the series-connected first and second switches MQ1 and MQ2. When both switches MQ1 and MQ2 are on, a complete current loop is formed on the input side of the optocoupler, allowing it to operate normally. When either switch MQ1 or MQ2 is off, the loop is broken, and the optocoupler stops working. Therefore, it can be seen that the logic judgment of the device door signal detection circuit is based on the combined state of the first switch MQ1 and the second switch MQ2. Specifically, when both the first switch MQ1 and the second switch MQ2 are controlled to be in the on state by the first detection branch and the second detection branch, the input side of the optocoupler is activated, and the optocoupler starts to work. At this time, the door status signal output branch outputs a first level signal, which indicates that the device door is in a certain specific state, such as indicating that the device door is closed and the door sensor J1 is properly connected. When at least one of the first switch MQ1 and the second switch MQ2 is in the off state, the input side circuit of the optocoupler is cut off, the optocoupler stops working, and the door status signal output branch outputs a second level signal, which indicates that the device door is in another state, such as the device door is open or the door sensor J1 is malfunctioning. Thus, by distinguishing between the two different level signals, the different states of the device door can be accurately characterized.

[0028] Understandably, in traditional detection circuits, for normally closed door sensor J1, the signal output terminal 4 is floating in both the normal closed and open-circuit states, resulting in the same output signal level and making it impossible to distinguish between an open circuit and a closed door. However, by introducing dual-channel detection into the equipment door signal detection circuit, simultaneously detecting the potential state of the signal output terminal 4 of door sensor J1 and the current state of the power supply return terminal 9, the technical problem of traditional single-channel circuits being unable to distinguish between a closed door and a sensor open circuit is effectively solved. This provides more comprehensive and reliable door status information, accurately determining the open / closed state of the equipment door and detecting the connection status of door sensor J1, thereby improving equipment safety and operational reliability and avoiding potential safety hazards caused by misjudgments.

[0029] like Figure 2As shown, the second detection branch includes a second operational amplifier U2 and a sampling resistor Rs. One end of the sampling resistor Rs is connected to the power supply return terminal 9 of the gate sensor J1, and the other end is grounded. The positive input terminal 5 and the negative input terminal 6 of the second operational amplifier U2 are coupled to the two ends of the sampling resistor Rs through a resistor network. The output terminal 7 of the second operational amplifier U2 is connected to the control terminal of the second switch MQ2. The second detection branch uses the inherent current of the power supply circuit of the gate sensor J1 as a judgment basis to judge the online status of the gate sensor J1 and generate a corresponding level control signal to drive the switching of the second switch MQ2. Specifically, the sampling resistor Rs is connected in series between the power supply return terminal 9 of the gate sensor J1 and ground. When there is a return current, according to Ohm's law, a voltage drop proportional to the current will be generated across the sampling resistor Rs. This voltage drop is the sampling result of the current signal. The sampling resistor Rs needs to ensure sufficient voltage signal amplitude while minimizing its impact on the operation of the return circuit itself, avoiding excessive power consumption or voltage drop. Therefore, a 100-ohm resistor can be used for the sampling resistor Rs.

[0030] The second operational amplifier U2 is used to amplify, compare, or differentially process the voltage signal across the sampling resistor Rs. For example, it can act as a voltage comparator, comparing the voltage across the sampling resistor Rs with a preset threshold voltage to determine if there is a backflow current; or it can act as a differential amplifier, measuring the small voltage difference across the sampling resistor Rs. Specifically, the positive input terminal 5 of the second operational amplifier U2 is coupled to the high potential terminal of the sampling resistor Rs through a resistor network, and the negative input terminal 6 is coupled to the ground terminal of the sampling resistor Rs through a resistor network. This allows the second operational amplifier U2 to amplify the voltage signal across the sampling resistor Rs, converting the weak current signal into a clear level signal to drive the second switching transistor MQ2.

[0031] The resistor network is used to couple the voltage signal across the sampling resistor Rs to the positive input terminal 5 and the negative input terminal 6 of the second operational amplifier U2. The resistor network includes multiple resistors. For example, the resistor network can be used to divide the voltage across the sampling resistor Rs to fit the resistor network of the operational amplifier, ensuring that the second operational amplifier U2 can accurately process the voltage signal from the sampling resistor Rs, thereby achieving accurate detection of the return current.

[0032] Specifically, the return current of door sensor J1 is converted into a measurable voltage signal through sampling resistor Rs. This voltage signal is coupled to the second operational amplifier U2 through a resistor network, where it is amplified. When a valid return current is detected, the second operational amplifier U2 outputs a high-level signal, turning on the second switch MQ2. Conversely, when no valid current is detected, the second operational amplifier U2 outputs a low-level signal, turning off the second switch MQ2. Therefore, the second detection branch can determine the online status of door sensor J1 and control the on / off state of the second switch MQ2, thus forming a logic output together with the first detection branch, improving the accuracy of the door detection circuit's judgment of the door status.

[0033] Understandably, the resistor network in the second detection branch includes a first voltage divider resistor R6, a second voltage divider resistor R7, a third input resistor R4, and a fourth feedback resistor R5. Specifically, one end of the sampling resistor Rs is connected to the positive input terminal 5 of the second operational amplifier U2 through the first voltage divider resistor R6, and the second voltage divider resistor R7 is connected between the positive input terminal 5 of the second operational amplifier U2 and ground. The first voltage divider resistor R6 and the second voltage divider resistor R7 together form a voltage divider network, used to divide the voltage at one end of the sampling resistor Rs and apply the divided voltage to the positive input terminal 5 of the second operational amplifier U2. By selecting a resistance value of 100 ohms for the first voltage divider resistor R6 and a resistance value of 100K ohms for the second voltage divider resistor R7, it can be ensured that the voltage signal entering the positive input terminal 5 of the second operational amplifier U2 is within a suitable range, and it helps to suppress common-mode interference and improve the signal-to-noise ratio. Meanwhile, the other end of the sampling resistor Rs is connected to the negative input terminal 6 of the second operational amplifier U2 through the third input resistor R4, and the fourth feedback resistor R5 is connected between the output terminal 7 and the negative input terminal 6 of the second operational amplifier U2. The resistance values ​​of the third input resistor R4 and the fourth feedback resistor R5 together determine the amplification factor of the voltage difference across the sampling resistor Rs by the second operational amplifier U2. The fourth feedback resistor R5, connected between the output terminal 7 and the negative input terminal 6 of the second operational amplifier U2, forms a negative feedback loop, which can stabilize the operating point of the second operational amplifier U2 and, together with the third input resistor R4, set the gain of the differential amplifier. Therefore, using the resistor network, the second operational amplifier U2 can amplify the small voltage difference across the sampling resistor Rs with high precision, thereby accurately reflecting the magnitude of the return current flowing through the sampling resistor Rs.

[0034] In other words, the second detection branch, through the first voltage divider resistor R6, the second voltage divider resistor R7, the third input resistor R4, and the fourth feedback resistor R5, constructs a precise differential amplifier circuit for the second operational amplifier U2. This allows the second operational amplifier U2 to accurately detect the minute voltage difference across the sampling resistor Rs caused by the return current, effectively suppressing common-mode noise interference and thus improving the accuracy and stability of the return current detection. Therefore, it effectively improves the reliability of the on / off control of the second switching transistor MQ2, avoids misjudgment of the gate state due to inaccurate current detection, and ultimately ensures the overall reliability and accuracy of the device's gate signal detection circuit.

[0035] In addition, the second detection branch also includes a second branch current-limiting resistor R8, a second branch filter capacitor C4, and a second branch filter resistor R9. The second branch current-limiting resistor R8 is connected in series between the output terminal 7 of the second operational amplifier U2 and the control terminal of the second switching transistor MQ2. The second branch filter capacitor C4 and the second branch filter resistor R9 are connected in parallel to ground between the second branch current-limiting resistor R8 and the control terminal of the second switching transistor MQ2. The second branch current-limiting resistor R8 limits the peak current when the second operational amplifier U2 charges the second branch filter capacitor C4, protecting electronic components and increasing the high-frequency impedance of the branch, thus improving output stability. Furthermore, the second branch current-limiting resistor R8 and the second branch filter capacitor C4 can form a first-order low-pass filter to reduce electromagnetic interference. Similarly, the second branch filter capacitor C4 and the second branch filter resistor R9 can also be connected in parallel to form a low-pass filter, smoothing the drive signal and reducing voltage overshoot during the switching process. It should also be noted that when the output of the second operational amplifier U2 is low, the second branch filter resistor R9 can pull down the control terminal of the second switch MQ2 to ground potential, ensuring that the second switch MQ2 is in the off state and avoiding false turn-on due to floating.

[0036] Understandably, when the gate sensor J1 is a normally closed sensor, the first detection branch includes a first operational amplifier U1 and a fifth pull-up resistor R1. Specifically, the first operational amplifier U1 is a high-gain differential amplifier with high input impedance and low output impedance, capable of signal buffering, amplification, or comparison. It is worth noting that the first operational amplifier U1 and the second operational amplifier U2 can use the same model, forming different circuit functions through different circuit connections. In one embodiment, the first operational amplifier U1 is configured as a voltage follower, providing high input impedance to avoid load effects on the signal output terminal 4 of the gate sensor J1, while providing low output impedance to stably drive the control terminal of the subsequent first switching transistor MQ1. The fifth pull-up resistor R1 is a resistor connected between the signal line and the first reference power supply, capable of pulling the positive input terminal 3 of the first operational amplifier U1 high to a defined logic high level when the signal output terminal 4 of the gate sensor J1 is in a floating high-impedance state or is not actively pulled low.

[0037] In this configuration, the positive input terminal 3 of the first operational amplifier U1 is connected to the first reference power supply via a fifth pull-up resistor R1, and simultaneously connected to the signal output terminal 4 of the gate sensor J1. Therefore, when the signal output terminal 4 of the gate sensor J1 is in a floating, high-impedance state, it is pulled up to the level of the first reference power supply via the fifth pull-up resistor R1, and sampled by the positive input terminal 3 of the first operational amplifier U1, providing a clear input signal for the first operational amplifier U1. When the signal output terminal 4 of the gate sensor J1 is grounded, even though the fifth pull-up resistor R1 is connected to the first reference power supply, the positive input terminal 3 of the first operational amplifier U1 is still pulled low. Simultaneously, the negative input terminal 2 of the first operational amplifier U1 is shorted to the output terminal 1, configuring the first operational amplifier U1 as a voltage follower. In this case, the output voltage of the first operational amplifier U1 will follow the voltage of the positive input terminal 3, and it will have extremely high input impedance and extremely low output impedance. Since the output terminal 1 of the first operational amplifier U1 is connected to the control terminal of the first switching transistor MQ1, the buffer signal output by the first operational amplifier U1 is directly used to control the on / off state of the first switching transistor MQ1. Therefore, it can be ensured that the first switching transistor MQ1 switches accordingly based on the potential state of the signal output terminal 4 of the door sensor J1.

[0038] In other words, the first detection branch incorporates a first operational amplifier U1 and a fifth pull-up resistor R1. The fifth pull-up resistor R1 ensures that the signal output terminal 4 of the door sensor J1 can be reliably pulled high to the first reference power supply level when floating at high impedance, and stably pulled low when grounded. Simultaneously, the first operational amplifier U1 is configured as a voltage follower, enabling the first switching transistor MQ1 to perform accurate and reliable on / off control based on the actual potential state of the door sensor J1. This effectively improves the stability and anti-interference capability of the first detection branch in detecting the door sensor J1 signal, thereby enhancing the reliability and accuracy of the entire device's door signal detection circuit.

[0039] For the normally closed door sensor J1, when the equipment door is closed, the signal output terminal 4 of the door sensor J1 is in a floating high-impedance state, and the first detection branch controls the first switch MQ1 to conduct; when the equipment door is open, the signal output terminal 4 is in a grounded state, and the first detection branch controls the first switch MQ1 to turn off. Specifically, the floating high-impedance state means that the signal output terminal 4 of the door sensor J1 is neither actively pulled high nor actively pulled low, exhibiting high impedance characteristics. That is, the switch in the internal circuit of the door sensor J1 is off. At this time, the first detection branch pulls the potential of the signal output terminal 4 in the floating high-impedance state to a high level through the fifth pull-up resistor R1, and compares it with a preset reference voltage. When the signal output terminal 4 forms a high level through internal pull-up, the first operational amplifier U1 outputs a high level, thereby driving the first switch MQ1 to conduct. In addition, the grounded state means that the signal output terminal 4 of the door sensor J1 is actively connected to the ground potential, which is actually pulled low to the same potential as the power supply return terminal 9. For example, this can be achieved by closing the reed switch or Hall sensor inside the door sensor J1 when the door is opened, directly pulling the signal output terminal 4 low to ground potential. When the signal output terminal 4 is pulled low, the first operational amplifier U1 outputs a low level, thereby turning off the first switch MQ1.

[0040] In other words, when using a normally closed door sensor J1, the signal output terminal 4 is in a floating high-resistance state when the equipment door is closed, and in a grounded state when the equipment door is open. This allows the first detection branch to accurately identify the physical state of the door sensor J1. When the equipment door is closed, the first detection branch identifies the floating high-resistance state as a high level and controls the first switch MQ1 to conduct; when the equipment door is open, the first detection branch identifies the grounded state as a low level and controls the first switch MQ1 to cut off, ensuring that the on / off state of the first switch MQ1 is consistent with the actual opening / closing state of the equipment door.

[0041] When the door sensor J1 is a normally open sensor, an inverter can be added to the existing circuit architecture of the first detection branch described above. The input of the inverter is connected to the signal output terminal 4, and the output of the inverter is connected to the control terminal of the first switch MQ1. In this case, when the device door is closed, the signal output terminal 4 is grounded, and the first detection branch controls the first switch MQ1 to conduct; when the device door is open, the signal output terminal 4 is in a floating high-impedance state, and the first detection branch controls the first switch MQ1 to cut off. Specifically, an inverter is a logic gate circuit whose output signal logic state is opposite to the input signal logic state; that is, when the input is high, the output is low; when the input is low, the output is high. The inverter can be implemented using a CMOS inverter, a TTL inverter, or other types of digital logic inverters. The input of the inverter is electrically connected to the signal output terminal 4 of the door sensor J1 via wires or PCB traces to receive the original door status signal emitted by the door sensor J1. The output of the inverter is also electrically connected to the control terminal of the first switching transistor MQ1 via wires or PCB traces, so as to transmit the signal after inversion to the first switching transistor MQ1 to realize the control of the first switching transistor MQ1.

[0042] At this time, the control logic of the normally open sensor is exactly the opposite of that of the normally closed sensor. When the equipment door is closed, the signal output terminal 4 of the door sensor J1 is grounded, which means that the signal output terminal 4 is at a low level. At this time, the input terminal of the inverter receives a low-level signal, and after inversion, the output terminal will output a high-level signal. This high-level signal is applied to the control terminal of the first switch MQ1, thereby driving the first switch MQ1 to conduct. When the equipment door is open, the signal output terminal 4 of the door sensor J1 is in a floating high-impedance state. Since the signal output terminal 4 is connected to the first reference power supply through the fifth pull-up resistor R1, the floating high-impedance state is identified as a high level. At this time, the input terminal of the inverter receives a high-level signal, and after inversion, the output terminal will output a low-level signal. This low-level signal is applied to the control terminal of the first switch MQ1, thereby driving the first switch MQ1 to turn off. Therefore, by introducing an inverter in the first detection branch, the problem of mismatch between the potential state of the signal output terminal 4 of different types of door sensors J1 and the control logic of the first switch MQ1 can be solved.

[0043] Understandably, when the door sensor J1 is a normally open sensor, adjustments are made to the first detection branch described above to accommodate different control logics for different types of door sensors J1. Specifically, the first detection branch includes a first operational amplifier U1, a fifth pull-up resistor R1, a sixth input resistor, and a seventh feedback resistor. One end of the fifth pull-up resistor R1 is connected to the first reference power supply, and the other end is connected to the signal output terminal 4. The negative input terminal 2 of the first operational amplifier U1 is connected to the signal output terminal 4 through the sixth input resistor, the output terminal 1 of the first operational amplifier U1 is connected to the negative input terminal 2 of the first operational amplifier U1 through the seventh feedback resistor, and the positive input terminal 3 of the first operational amplifier U1 is connected to the second reference power supply.

[0044] Specifically, in this embodiment, the first operational amplifier U1 is configured as an inverting amplifier. One end of the fifth pull-up resistor R1 is connected to the first reference power supply, and the other end is connected to the signal output terminal 4. When the signal output terminal 4 of the gate sensor J1 is in a floating high-impedance state, it pulls the potential of the signal output terminal 4 up to the voltage of the first reference power supply, thereby providing a clear logic high-level input for the first operational amplifier U1. The sixth input resistor is connected between the signal output terminal 4 and the negative input terminal 2 of the first operational amplifier U1 to limit the current flowing to the input terminal of the operational amplifier and protect the operational amplifier. The seventh feedback resistor is connected between the output terminal 1 and the negative input terminal 2 of the first operational amplifier U1, and together with the sixth input resistor, forms a negative feedback network to stably configure the first operational amplifier U1 as an inverting amplifier. For example, when the resistance values ​​of the sixth input resistor and the seventh feedback resistor are equal, the gain of the inverting amplifier is -1, that is, the output voltage is equal to the inverted input voltage.

[0045] The first reference power supply provides a stable high-level reference voltage to the fifth pull-up resistor R1, while the second reference power supply provides a stable reference voltage to the positive input terminal 3 of the first operational amplifier U1. The second reference power supply can be obtained by voltage division of the first reference power supply, such as when the reference voltage provided by the second reference power supply is half the voltage provided by the first reference power supply. This reference voltage serves as the comparison reference point for the inverter, ensuring that the first operational amplifier U1 can accurately invert the potential at the signal output terminal 4 to generate the required logic control signal.

[0046] Therefore, the first detection branch uses the first operational amplifier U1, the fifth pull-up resistor R1, the sixth input resistor, and the seventh feedback resistor to form an inverter circuit. The fifth pull-up resistor R1 ensures that the signal output terminal 4 has a clear high level in the floating high-impedance state. The first operational amplifier U1 inverts the voltage of the signal output terminal 4 through the feedback network formed by the sixth input resistor and the seventh feedback resistor, and uses the second reference power supply as a reference. This allows the first detection branch to invert the logic level of the signal output terminal 4 of the normally open door sensor J1 into the required control logic, while filtering out noise at the signal output terminal 4, thereby generating a stable and reliable control signal to accurately control the on / off state of the first switching transistor MQ1.

[0047] It is understandable that, regardless of whether the door sensor J1 is normally closed or normally open, the first detection branch also includes a first filter capacitor C1. One end of the first filter capacitor C1 is connected to the connection point between the signal output terminal 4 and the fifth pull-up resistor R1, and the other end of the first filter capacitor C1 is grounded.

[0048] The first filter capacitor C1 effectively filters out high-frequency noise and instantaneous voltage spikes that may exist on the signal output terminal 4 of the door sensor J1, thereby providing a cleaner and more stable signal to the positive input terminal 3 of the first operational amplifier U1, ensuring more accurate and reliable on / off control of the first switching transistor MQ1. Therefore, the device door signal detection circuit of this application can maintain high detection accuracy and stability even in complex electromagnetic environments, effectively improving the anti-interference capability and operational reliability of the entire door status detection system.

[0049] In addition, the first detection branch also includes a first branch current-limiting resistor R2, a first branch filter capacitor C2, and a first branch filter resistor R3. The first branch current-limiting resistor R2 is connected in series between the output terminal 1 of the first operational amplifier U1 and the control terminal of the first switching transistor MQ1. The first branch filter capacitor C2 and the first branch filter resistor R3 are connected in parallel to ground between the first branch current-limiting resistor R2 and the control terminal of the first switching transistor MQ1. The first branch current-limiting resistor R2 can limit the peak current when the first operational amplifier U1 charges the first branch filter capacitor C2, protecting electronic components and increasing the high-frequency impedance of the branch to improve output stability. In addition, the first branch current-limiting resistor R2 and the first branch filter capacitor C2 can form a first-order low-pass filter to reduce electromagnetic interference. The first branch filter capacitor C2 and the first branch filter resistor R3 can also be connected in parallel to form a low-pass filter to smooth the drive signal and reduce voltage overshoot during the switching process. It should also be noted that when the output of the first operational amplifier U1 is low, the first branch filter resistor R3 can pull down the control terminal of the first switching transistor MQ1 to ground potential, ensuring that the first switching transistor MQ1 is in the off state and avoiding false turn-on due to floating.

[0050] Understandably, the gate state signal output branch also includes a pull-up resistor R11, a gate state filter resistor R12, and a gate state filter capacitor C5. Specifically, the collector of the optocoupler is connected to one end of the gate state filter resistor R12, the other end of the gate state filter resistor R12 serves as the signal output node, and the gate state filter capacitor C5 is connected between the signal output node and ground. Additionally, one end of the pull-up resistor R11 is connected to both the collector of the optocoupler and one end of the gate state filter resistor R12.

[0051] The pull-up resistor R11 is used to pull the collector potential up to the reference power supply voltage when the output transistor inside the optocoupler is turned off, thereby enabling the signal output node to obtain a stable high level; at the same time, when the optocoupler is turned on, the pull-up resistor limits the current flowing through the output transistor, thus playing a protective role.

[0052] The gate-state filter resistor R12 and the gate-state filter capacitor C5 together form a low-pass filter to attenuate high-frequency noise components in the signal and limit the current flowing through the optocoupler output, protecting subsequent circuitry. When high-frequency noise is present in the signal, the filter capacitor provides a low-impedance path, bypassing these high-frequency noise components to ground, thus making the voltage at the signal output node smoother and more stable. In other words, when the optocoupler is off, the current introduced by the pull-up resistor R11 first passes through the gate-state filter resistor R12, and then the other end of the gate-state filter resistor R12 serves as the signal output node. Simultaneously, the signal output node is connected to ground through the gate-state filter capacitor C5, which attenuates high-frequency noise, resulting in a purified and more stable gate-state signal at the signal output node.

[0053] By introducing a gate state filter resistor R12 and a gate state filter capacitor C5 into the gate state signal output branch and configuring them as an RC low-pass filter circuit, when the collector of the optocoupler is affected by external electromagnetic interference or power fluctuations, the filter resistor and filter capacitor can work together to bypass these high-frequency noise components to ground, thereby smoothing the signal waveform, eliminating signal glitches, and making the gate state signal obtained at the signal output node purer and more stable. This effectively reduces the risk of misjudging the gate state by the back-end circuit, improves the accuracy of the device gate signal detection and the overall reliability of the system, and is especially suitable for application scenarios with complex noise environments such as industrial environments.

[0054] This application also proposes a device for detecting device door signals, including a door sensor and the aforementioned device door signal detection circuit. The door sensor includes a power input terminal for connecting to an external power source, a power return terminal for outputting return current, and a signal output terminal for switching the potential state based on the device door's on / off state.

[0055] It is worth noting that since the device door signal detection device of this application embodiment includes the device door signal detection circuit of the above embodiment, the specific implementation method and technical effect of the device door signal detection device of this application embodiment can refer to the specific implementation method and technical effect of the device door signal detection circuit of any of the above embodiments.

[0056] In the several embodiments provided in this application, it should be understood that the disclosed systems, instruments, and methods can be implemented in other ways. For example, the instrument embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between instruments or units may be electrical, mechanical, or other forms. Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0057] It should also be understood that the various implementation methods provided in this application can be combined arbitrarily to achieve different technical effects.

[0058] The above provides a detailed description of the preferred embodiments of this application. However, this application is not limited to the above-described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A device gate signal detection circuit, characterized in that, include: The first detection branch is used to connect to the signal output terminal of the door sensor and control the on / off state of the first switching transistor based on the potential state of the signal output terminal. The second detection branch is used to connect to the power supply return terminal of the door sensor, and to control the on / off state of the second switching transistor based on whether the power supply return terminal outputs a return current. The gate status signal output branch includes an optocoupler, a first switch and a second switch. The anode input terminal of the optocoupler is connected to an external power supply, and the cathode input terminal is grounded through the first switch and the second switch connected in series. Specifically, when both the first and second switching transistors are turned on, the optocoupler operates, and the gate status signal output branch outputs a first-level signal; when at least one of the first and second switching transistors is turned off, the optocoupler stops operating, and the gate status signal output branch outputs a second-level signal; the first-level signal and the second-level signal represent different gate states.

2. The device door signal detection circuit according to claim 1, characterized in that, The second detection branch includes a second operational amplifier and a sampling resistor. One end of the sampling resistor is connected to the power supply return terminal of the gate sensor, and the other end is grounded. The positive and negative input terminals of the second operational amplifier are coupled to the two ends of the sampling resistor through a resistor network. The output terminal of the second operational amplifier is connected to the control terminal of the second switching transistor.

3. The device door signal detection circuit according to claim 2, characterized in that, The second detection branch further includes a first voltage divider resistor, a second voltage divider resistor, a third input resistor, and a fourth feedback resistor. One end of the sampling resistor is connected to the positive input terminal of the second operational amplifier through the first voltage divider resistor, and the second voltage divider resistor is connected between the positive input terminal of the second operational amplifier and ground. The other end of the sampling resistor is connected to the negative input terminal of the second operational amplifier through the third input resistor, and the fourth feedback resistor is connected between the output terminal and the negative input terminal of the second operational amplifier.

4. The device door signal detection circuit according to claim 1, characterized in that, The first detection branch includes a first operational amplifier and a fifth pull-up resistor. The positive input terminal of the first operational amplifier is connected to a first reference power supply through the fifth pull-up resistor, and is also connected to the signal output terminal of the door sensor. The negative input terminal of the first operational amplifier is shorted to the output terminal, and the output terminal of the first operational amplifier is connected to the control terminal of the first switching transistor.

5. The device door signal detection circuit according to claim 4, characterized in that, The first detection branch also includes a first filter capacitor, one end of which is connected to the connection point between the signal output terminal and the fifth pull-up resistor, and the other end of which is grounded.

6. The device door signal detection circuit according to claim 1, characterized in that, When the equipment door is closed, the signal output terminal of the door sensor is in a floating high-impedance state, and the first detection branch controls the first switch to be turned on; when the equipment door is open, the signal output terminal is in a grounded state, and the first detection branch controls the first switch to be turned off.

7. The device door signal detection circuit according to claim 1, characterized in that, The first detection branch further includes an inverter, the input of which is connected to the signal output, and the output of which is connected to the control terminal of the first switch. When the equipment door is closed, the signal output is grounded, and the first detection branch controls the first switch to be turned on. When the equipment door is open, the signal output is in a floating high-impedance state, and the first detection branch controls the first switch to be turned off.

8. The device door signal detection circuit according to claim 1, characterized in that, The first detection branch includes a first operational amplifier, a fifth pull-up resistor, a sixth input resistor, and a seventh feedback resistor. One end of the fifth pull-up resistor is connected to a first reference power supply, and the other end is connected to the signal output terminal. The negative input terminal of the first operational amplifier is connected to the signal output terminal through the sixth input resistor. The output terminal of the first operational amplifier is connected to the negative input terminal of the first operational amplifier through the seventh feedback resistor. The positive input terminal of the first operational amplifier is connected to a second reference power supply.

9. The device door signal detection circuit according to claim 1, characterized in that, The gate state signal output branch also includes a gate state filter resistor and a gate state filter capacitor. The output terminal of the optocoupler is connected to one end of the gate state filter resistor, the other end of the gate state filter resistor serves as a signal output node, and the gate state filter capacitor is connected between the signal output node and ground.

10. A device for detecting door signals, characterized in that, The device includes a door sensor and a device door signal detection circuit as described in any one of claims 1 to 9, wherein the door sensor includes a power supply input terminal for connecting to an external power supply, a power supply return terminal for outputting return current, and a signal output terminal for switching potential states based on the switching state of the device door.

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