A virtual connection detection circuit, device and method

Abstract

The present application discloses a virtual connection detection circuit, device and method, relating to the field of circuit technology. The circuit includes: a comparator, a first resistor, a voltage divider and an indicator; the positive input terminal of the comparator is used to connect to the moving point of the voltage divider, the first end of the voltage divider is used to connect to the power supply voltage, and the second end of the voltage divider is used to be grounded; the negative input terminal of the comparator is used to connect to the first end of the first resistor, the second end of the first resistor is grounded, and the negative input terminal of the comparator is also used to connect to the first end of the wire to be detected, and the second end of the wire to be detected is used to connect to the input voltage; the output terminal of the comparator is used to connect to the indicator, and the indicator is used to indicate the detection result. The circuit can detect the virtual connection phenomenon, thereby ensuring that the wire is properly connected, thereby reducing the error of the test result.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a virtual connection detection circuit, device, and method. Background Art

[0002] In automotive engineering, bench testing is a critical technical link between design and product implementation. As a core method for verifying vehicle performance, it not only assesses the reliability of key modules such as the powertrain and electronic control system, but also provides a quantitative basis for optimizing design parameters through field-tested data, ensuring product quality from the source to meet stringent industry regulations and safety standards. Before commencing this sophisticated testing, engineers must complete a fundamental yet tedious pre-requisite: ensuring reliable connectivity of the vehicle's wiring system, including but not limited to CAN bus communication cables and low-voltage power cables.

[0003] Early wire connections relied on manual labor: engineers used wire stripping tools to remove the wire insulation, twisted the copper core, and then wrapped it with insulating tape. This solution, relying on the stability of the mechanical physical connection, ensured basic connectivity of the test circuit for a long period of time. With the increasing demand for test efficiency, standardized wire connection terminals emerged. These prefabricated components, through the quick connection of plugs and sockets, reduced the connection time of a single wire from minutes to seconds, significantly improving test bench construction efficiency.

[0004] However, while the standardized wire connection terminal approach can achieve quick connection, it is prone to false connections, which can distort test signals during transmission and lead to significant errors in test results. Summary of the Invention

[0005] The present application provides a circuit, device and method for detecting a virtual connection, which can detect the virtual connection phenomenon, thereby ensuring the normal connection of the wires and reducing the error of the test results.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a virtual connection detection circuit, the circuit comprising: a comparator, a first resistor, a voltage divider, and an indicator;

[0008] The positive input terminal of the comparator is used to connect to the moving point of the voltage divider, the first terminal of the voltage divider is used to connect to the power supply voltage, the second terminal of the voltage divider is used to be grounded, and the power supply voltage is used to power the voltage divider and the comparator;

[0009] The negative input terminal of the comparator is used to connect the first end of the first resistor, the second end of the first resistor is grounded, the negative input terminal of the comparator is also used to connect the first end of the wire to be detected, and the second end of the wire to be detected is used to connect the input voltage;

[0010] The output end of the comparator is used to connect to an indicator, and the indicator is used to indicate the detection result.

[0011] Optionally, the circuit further includes: a peak detection circuit and a filtering circuit;

[0012] The output end of the peak detection circuit is connected to the first end of the first resistor, the input end of the peak detection circuit is connected to the output end of the filter circuit, and the input end of the filter circuit is connected to the first end of the wire to be detected;

[0013] The filtering circuit is used to filter out interference signals and output target frequency band signals;

[0014] The peak detection circuit is used to convert the target frequency band signal into a DC signal.

[0015] Optionally, the peak detection circuit includes a first diode and a first capacitor;

[0016] The first end of the first capacitor is connected to the cathode of the first diode, the first end of the first capacitor is connected to the negative input end of the comparator, and the second end of the first capacitor is grounded; the anode of the first diode is used to connect to the filter circuit.

[0017] Optionally, the filtering circuit includes a high-pass filtering circuit and a low-pass filtering circuit;

[0018] The high-pass filter circuit includes a second capacitor and a second resistor, and the low-pass filter circuit includes a third capacitor and a third resistor;

[0019] The first end of the second capacitor is connected to the first end of the wire to be detected, the second end of the second capacitor is connected to the first end of the second resistor, and the second end of the second resistor is grounded;

[0020] The first end of the third resistor is connected to the second end of the second capacitor, the second end of the third resistor is connected to the first end of the third capacitor, and the second end of the third capacitor is grounded;

[0021] The second end of the third resistor is connected to the anode of the first diode.

[0022] Optionally, the circuit further includes a fourth capacitor;

[0023] The first end of the fourth capacitor is connected to the second end of the wire to be detected, and the second end of the fourth capacitor is used to connect to the power supply voltage.

[0024] Optionally, the voltage divider is further used to adjust the voltage provided by the power supply voltage to the positive input terminal of the comparator.

[0025] Optionally, the power supply terminal of the comparator is used to connect to a power supply voltage, and the ground terminal of the comparator is used to be grounded.

[0026] Optionally, when the voltage at the positive input terminal of the comparator is greater than the voltage at the negative input terminal of the comparator, the output terminal of the comparator outputs the power supply voltage.

[0027] Optionally, the indicator includes a light-emitting device, a sound-emitting device or a vibration device.

[0028] In a second aspect, the present application provides a virtual connection detection device, which includes a wire fixing device and any optional virtual connection detection circuit in the first aspect.

[0029] In a third aspect, the present application provides a virtual connection detection circuit, which is applied to any optional virtual connection detection circuit in the first aspect, and the method includes:

[0030] Get the indication content of the indicator;

[0031] According to the instruction content, a detection result of the virtual connection detection is determined.

[0032] It can be seen from the above technical solution that this application has at least the following beneficial effects:

[0033] The present application provides a virtual connection detection circuit, which includes a comparator, a first resistor, a voltage divider and an indicator. The positive input terminal of the comparator is used to connect the moving point of the voltage divider, the first end of the voltage divider is used to connect the power supply voltage, the second end of the voltage divider is used to ground, the negative input terminal of the comparator is used to connect the first end of the first resistor, the second end of the first resistor is grounded, the negative input terminal of the comparator is also used to connect the first end of the wire to be detected, the second end of the wire to be detected is used to connect the input voltage, the output terminal of the comparator is used to connect the indicator, and the indicator is used to indicate the detection result. In the circuit of the present application, the voltage of the positive input terminal of the comparator can be set by the voltage divider. After the setting is completed, if there is a virtual connection in the wire to be detected, a part of the voltage will be divided from the two ends of the first resistor, thereby reducing the voltage at both ends of the first resistor, that is, the voltage of the negative input terminal will be reduced. When the voltage of the positive input terminal is reasonably set, the voltage of the negative input terminal will be lower than the voltage of the positive input terminal. At this time, the output terminal of the comparator will output the power supply voltage to the indicator, and the indicator will indicate the detection result of the presence of virtual connection.

[0034] It should be understood that the description of technical features, technical solutions, beneficial effects or similar language in this application does not imply that all features and advantages can be realized in any single embodiment. On the contrary, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution or beneficial effect is included in at least one embodiment. Therefore, the description of a technical feature, technical solution or beneficial effect in this specification does not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions and beneficial effects described in the present embodiment can also be combined in any appropriate manner. Those skilled in the art will understand that the embodiment can be implemented without one or more specific technical features, technical solutions or beneficial effects of a specific embodiment. In other embodiments, additional technical features and beneficial effects can also be identified in specific embodiments that do not embody all embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a virtual connection detection circuit provided in an embodiment of the present application;

[0036] Figure 2 A schematic diagram of another virtual connection detection circuit provided in an embodiment of the present application;

[0037] Figure 3 A schematic diagram of a peak detection circuit provided in an embodiment of the present application;

[0038] Figure 4 A schematic diagram of a filter circuit provided in an embodiment of the present application;

[0039] Figure 5 A design diagram of a virtual connection detection circuit provided in an embodiment of the present application;

[0040] Figure 6 A schematic diagram of a virtual connection detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The terms "first", "second" and "third" in this application specification and the accompanying drawings are used to distinguish different objects rather than to limit a specific order.

[0042] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0043] To make the description of the following embodiments clear and concise, a brief introduction to the related technologies is first given:

[0044] A loose connection in a wire refers to an abnormal connection state in which the wire and the terminal, device pin, or other conductor appear to be in good contact during an electrical connection, but in reality, the contact is insufficient and the conductivity is unstable. This hidden fault manifests as a defective electrical connection despite not being completely physically separated. The difference between a loose connection and an open circuit is that in the case of a loose connection, the conductive path is not completely disconnected, but a contact defect exists, manifesting as an abnormally increased contact resistance and an unstable connection state. When an analog signal (such as a sensor voltage signal) is loosely connected, the contact resistance introduces additional voltage drop or noise, causing test data distortion and fluctuations (such as bit errors and frame loss in CAN bus signals). A loose connection in a digital signal may cause edge jitter and logic level jumps, leading to misjudgment by the control module (such as a loose connection in a low-voltage power line causing the device to intermittently restart). It can be seen that a loose connection in a wire will result in large signal errors.

[0045] In view of this, the embodiment of the present application provides a virtual connection detection circuit. Figure 1 As shown in the figure, this figure is a schematic diagram of a virtual connection detection circuit provided in an embodiment of the present application.

[0046] The virtual connection detection circuit includes a comparator U3, a first resistor R5, a voltage divider RP and an indicator Vi.

[0047] The positive input terminal of the comparator U3 is used to connect to the moving point D of the voltage divider RP, the first terminal of the voltage divider RP is used to connect to the power supply voltage VCC, the second terminal of the voltage divider RP is used to be grounded, and the power supply voltage VCC is used to power the voltage divider RP and the comparator U3.

[0048] The negative input terminal of the comparator U3 is connected to the first end of the first resistor R5, and the second end of the first resistor R5 is grounded. The negative input terminal of the comparator U3 is also connected to the first end of the conductor RC to be detected, and the second end of the conductor RC to be detected is connected to the input voltage V_in. The conductor RC to be detected refers to a portion of the conductor in the circuit to be detected, such as a conductor including a joint.

[0049] The output end of the comparator U3 is used to connect to the indicator Vi, which is used to indicate the detection result.

[0050] from Figure 1It can be seen that the positive input voltage V3 of the positive input terminal of the comparator U3 will no longer change after the moving point D of the voltage divider is fixed (when the power supply voltage remains unchanged). It can be seen from the virtual connection phenomenon that after the virtual connection occurs, the resistance at the virtual connection will abnormally increase, and the input voltage V_in is divided by the first resistor R5 and the wire to be detected RC. When the resistance at the virtual connection increases abnormally, the voltage across the first resistor R5 will decrease. As a result, the negative input voltage V4 of the negative input terminal of the comparator U3 will decrease. By reasonably setting the position of the moving point D of the voltage divider RP, the negative input voltage V4 of the comparator U3 can be made smaller than the positive input voltage V3 when there is a virtual connection, and then the output terminal of the comparator U3 outputs the power supply voltage, and the indicator Vi can indicate the detection result.

[0051] In the absence of a virtual connection, the resistance of the wire RC to be detected is almost zero, and the input voltage V_in is almost entirely applied to the first resistor R5, so that the negative input voltage V4 of the negative input terminal of the comparator U3 is close to the input voltage V_in. By reasonably setting the position of the moving point D of the voltage divider RP, it can be made that in the absence of a virtual connection, the negative input voltage V4 of the comparator U3 is greater than the positive input voltage V3, and thus the output terminal of the comparator U3 does not output a voltage, and the indicator Vi can indicate the detection result.

[0052] Combined with the above Figure 1 , the principle of the virtual connection detection circuit provided in the embodiment of the present application is introduced, and the overall technical solution of the present application is introduced below.

[0053] like Figure 2 As shown in FIG, this figure is a schematic diagram of another virtual connection detection circuit provided by an embodiment of the present application. Figure 1 The following is a detailed introduction.

[0054] In some examples, the virtual connection detection circuit further includes a peak detection circuit 300 and a filter circuit 400; wherein the peak detection circuit is as follows: Figure 3 As shown, the filter circuit is as Figure 4 See also Figure 2 The output of peak detection circuit 300 is connected to the first end of first resistor R5. The input of peak detection circuit 300 is connected to the output of filter circuit 400. The input of filter circuit 400 is connected to the first end of the conductor RC to be detected. Filter circuit 400 is used to filter out interference signals and output a target frequency band signal. Peak detection circuit 300 is used to convert the target frequency band signal into a DC signal.

[0055] The filter circuit 400 includes a high-pass filter circuit 401 and a low-pass filter circuit 402. The high-pass filter circuit 401 includes a second capacitor C2 and a second resistor R3, and the low-pass filter circuit 402 includes a third capacitor C5 and a third resistor R4. The first end of the second capacitor C2 is connected to the first end of the wire to be detected RC, the second end of the second capacitor C2 is connected to the first end of the second resistor R3, and the second end of the second resistor R3 is grounded. The first end of the third resistor R4 is connected to the second end of the second capacitor C2, the second end of the third resistor R4 is connected to the first end of the third capacitor C5, and the second end of the third capacitor C5 is grounded. The second end of the third resistor R4 is connected to the anode of the first diode D1.

[0056] For a low-pass filter circuit, the cutoff frequency is calculated as:

[0057]

[0058] In the formula, Represents the cutoff frequency of the low-pass filter circuit, represents the resistance of the third resistor, Indicates the capacitance of the third capacitor.

[0059] For a high-pass filter circuit, the cutoff frequency is calculated as:

[0060]

[0061] In the formula, Represents the cutoff frequency of the high-pass filter circuit, represents the resistance value of the second resistor, Indicates the capacitance of the second capacitor.

[0062] In this way, the high-pass filter circuit 401 and the low-pass filter circuit 402 can form a band-pass filter, and the band-pass frequency range is: ,in, is the passband frequency range of the bandpass filter.

[0063] Peak detection circuit 300 is used to convert a target frequency band signal, which has passed through a bandpass filter consisting of a high-pass filter circuit 401 and a low-pass filter circuit 402, into a DC signal. The target frequency band signal is a signal within the bandpass frequency range of the bandpass filter. After being converted to a DC signal, the target frequency band signal is subsequently input into comparator U3 for virtual connection determination.

[0064] In some examples, the peak detection circuit includes a first diode D1 and a first capacitor C6. A first terminal of the first capacitor C6 is connected to the cathode of the first diode D1, a first terminal of the first capacitor C6 is connected to the negative input terminal of the comparator U3, and a second terminal of the first capacitor C6 is grounded. The anode of the first diode D1 is connected to the filter circuit 400.

[0065] The working principle of the peak detection circuit 300 is as follows: during the positive half cycle of the target frequency band signal, the first diode D1 is turned on, and the current passes through the first diode to charge the first capacitor C6. The voltage across the first capacitor C6 rises to the peak value of the target frequency band signal, that is, .in, represents the voltage across the first capacitor C6, Indicates the peak value of the target frequency band signal, represents the forward voltage drop of the first diode, for example, =0.3V. During the negative half-cycle of the target frequency band signal, the first diode D1 is in the cutoff phase. Since the impedance of the first diode D1 is very large when the reverse current passes through the first diode D1, the first capacitor C6 discharges very slowly, essentially maintaining the peak voltage. Because the first capacitor C6 charges quickly but discharges very slowly, the target frequency band signal is successfully converted into a DC signal, and the voltage of the first capacitor C6 is approximately equal to the peak voltage of the target frequency band signal.

[0066] In some examples, the virtual connection detection circuit further includes a fourth capacitor C1, a first end of which is connected to the second end of the conductor RC to be detected, and a second end of which is connected to a power supply voltage. The fourth capacitor is a coupling capacitor that allows AC signals to pass through while isolating DC signals. Specifically, the fourth capacitor allows high-frequency square wave signals to flow toward the conductor RC to be detected, thereby preventing DC current in the circuit to be detected, where the conductor RC is located, from flowing back into the virtual connection detection circuit, thereby significantly interfering with the detection results of the virtual connection detection circuit.

[0067] In some embodiments, the voltage divider RP is also used to adjust the voltage provided to the positive input terminal of the comparator U3 by the power supply voltage. For example, when the moving point D of the voltage divider RP moves toward the first end of the voltage divider RP, the resistance between the moving point D of the voltage divider RP and the first end of the voltage divider RP becomes smaller, that is, the voltage division becomes smaller, and then the voltage provided to the positive input terminal of the comparator U3 by the power supply voltage will become larger, that is, the voltage threshold for comparison is increased; when the moving point D of the voltage divider RP moves toward the second end of the voltage divider RP, the resistance between the moving point D of the voltage divider RP and the first end of the voltage divider RP becomes larger, that is, the voltage division becomes larger, and then the voltage provided to the positive input terminal of the comparator U3 by the power supply voltage will become smaller, that is, the voltage threshold for comparison is lowered. In this way, the virtual connection detection circuit provided in the embodiment of the present application can adjust the voltage threshold for comparison based on the actual detection scenario, so that the virtual connection detection circuit can be compatible with multiple detection scenarios and expand the scope of detection.

[0068] In some examples, the power supply terminal of the comparator U3 is used to connect to the power supply voltage, and the ground terminal of the comparator U3 is used to be grounded. Exemplarily, the virtual connection detection circuit includes a voltage regulator U1, which is used to ensure the stability of the power supply voltage. For example, the voltage regulator U1 can be a low dropout regulator (LDO) with an output voltage of 3.3V. The voltage regulator U1 includes three pins: U1_1-in pin (for connecting to the power supply voltage), U1_2-GND pin (for grounding), and U1_3-OUT pin (for connecting to the power supply terminal of the comparator U3, and also connected to the first terminal of the voltage divider RP).

[0069] In some examples, the virtual contact detection circuit includes a high-frequency oscillator circuit, which includes a timer U2, a fourth resistor R1, a fifth resistor R2, a fifth capacitor C3, and a sixth capacitor C4. Specifically, the timer U2 can be a 555 timer, and the pins and functions of the timer U2 are shown in Table 1 below.

[0070] Table 1: U2 pins and functions

[0071] Pins Function U2_1-GND Connection point U2_2-TRIG Trigger input, this pin can determine whether its voltage is less than one-third of VCC (power supply voltage) U2_3-OUT Output terminal, outputs high frequency square wave signal, the absolute value of the high level is approximately the value of VCC U2_4-RESET The reset terminal should be connected to a high level during normal operation U2_5-CONT The control voltage terminal is generally not used and should be connected to ground via a 10nF capacitor to prevent high-frequency interference. U2_6-THRES This pin will determine whether its voltage is greater than two-thirds of VCC U2_7-DISCH Discharge end U2_8-VCC Connect to the positive pole of the power supply

[0072] For the 555 timer, U2_1-GND is connected to ground, U2_8-VCC and U2_4-RESET are connected to power, U2_5-CONT is connected to a 10nF capacitor and then to ground, and U2_3-OUT is the output. U2_2-TRIG, U2_6-THRES, and U2_7-DISCH require different connections depending on the application scenario. In this application, an astable oscillator circuit constructed using a 555 timer, capacitors, and resistors is used to generate a high-frequency square wave signal. This circuit is low-cost and compact.

[0073] Combine Figure 2As shown, the first end of the fourth resistor R1 is connected to the U1_3-OUT pin of the voltage regulator U1, the second end of the fourth resistor R1 is connected to the first end of the fifth resistor R2, the second end of the fifth resistor R2 is connected to the U2_2-TRIG pin of the timer U2, and the first end of the fifth resistor R2 is connected to the U2_7-DISCH pin of the timer U2; the U2_1-GND pin of the timer U2 is grounded, the U2_2-TRIG pin is connected to the first end of the fifth capacitor C3, the second end of the fifth capacitor C3 is grounded, the U2_3-OUT pin is connected to the second end of the fourth capacitor C1, the U2_4-RESET pin is connected to the U1_3-OUT pin of the voltage regulator U1, the U2_5-CONT pin is connected to the first end of the sixth capacitor C4, the second end of the sixth capacitor C4 is grounded, the U2_6-THRES pin is connected to the first end of the fifth capacitor C3, and the U2_8-VCC pin is connected to the U1_3-OUT pin of the voltage regulator U1. The frequency calculation formula of the high-frequency square wave signal that can be generated by this high-frequency oscillation circuit is:

[0074]

[0075] in, Indicates the high-frequency square wave signal that the high-frequency vibration circuit can generate. represents the resistance value of the fourth resistor, represents the resistance value of the fifth resistor, Indicates the capacitance of the fifth capacitor.

[0076] In some examples, the indicator Vi includes a light-emitting device, a sound-emitting device, or a vibration device. If the indicator Vi is a light-emitting device, the light-emitting device includes a light-emitting element and a protective resistor R6, wherein the light-emitting element can be a light-emitting diode LED1. The protective resistor R6 is used to limit the current flowing through the light-emitting diode LED1. The first end of the protective resistor R6 is connected to the output end of the comparator U3, the second end of the protective resistor R6 is connected to the anode of the light-emitting diode LED1, and the cathode of the light-emitting diode LED1 is grounded. When the voltage at the negative input end of the comparator U3 is less than the voltage at the positive input end, the output end of the comparator U3 outputs the power supply voltage, thereby causing current to flow through the light-emitting device, and the light-emitting element to emit light. Based on this light emission, the user can determine whether the wire RC to be detected has a loose connection; otherwise, there is no loose connection.

[0077] In the case where the indicator Vi is a sound-generating device, the sound-generating device includes a sound element and a protective resistor, wherein the sound element can be a buzzer, and the protective resistor is used to limit the current flowing through the buzzer. The first end of the protective resistor is connected to the output end of the comparator U3, the second end of the protective resistor is connected to one end of the buzzer, and the other end of the buzzer is grounded. When the voltage at the negative input end of the comparator U3 is less than the voltage at the positive input end, the output end of the comparator U3 outputs the power supply voltage, thereby causing current to flow through the sound-generating device, and the sound-generating device to emit a sound. Based on this sound, the user can know that there is a loose connection in the test wire RC; otherwise, there is no loose connection.

[0078] If indicator Vi is a vibrating device, the vibrating device includes a vibrating element and a protective resistor. The vibrating element may be a vibrating motor, and the protective resistor is used to limit the current flowing through the vibrating motor. A first end of the protective resistor is connected to the output of comparator U3, a second end of the protective resistor is connected to one end of the vibrating motor, and the other end of the vibrating motor is grounded. When the voltage at the negative input of comparator U3 is less than the voltage at the positive input, the output of comparator U3 outputs the power supply voltage, causing current to flow through the vibrating device, causing the vibrating element to vibrate. This vibration allows the user to determine whether the conductor RC to be tested has a loose connection; otherwise, a loose connection is not present.

[0079] Based on the above description, the present invention aims at the common problem of false connection when using small wire connection terminals to achieve fast wire connection in bench testing, and proposes a false connection detection solution integrated into the terminal, namely a false connection detection circuit. The false connection detection circuit is based on high-frequency AC injection, bandpass filtering, peak detection and voltage division principles, and can monitor the false connection of the wire at the crimping point in the terminal in real time. Once a false connection phenomenon is detected, the indicator of the false connection detection circuit immediately issues a corresponding prompt to ensure that potential false connection faults are discovered and handled in a timely manner. The technical solution of the present application not only improves the reliability of wire connection, but also significantly enhances the safety and efficiency of the bench testing process, and effectively avoids signal distortion, transmission interruption and possible safety hazards caused by false connection.

[0080] like Figure 5 As shown in FIG, this figure is a design diagram of a virtual connection detection circuit provided by an embodiment of the present application. The virtual connection detection circuit includes a power supply module 601 , a high frequency oscillation module 602 , a bandpass filter 603 , a peak detection module 604 and a virtual connection alarm module 605 .

[0081] Among them, the power supply module 601 is composed of a battery S1 and a voltage regulator U1, which is used to provide a stable voltage for the virtual connection detection circuit; the high-frequency oscillation module 602 is composed of a timer U2, a fourth resistor R1, a fifth resistor R2, a fifth capacitor C3 and a sixth capacitor C4, which is used to emit a high-frequency square wave signal, that is, to convert the DC signal input by the power supply module 601 into an AC signal. The high-frequency square wave signal passes through the fourth capacitor C1 (the function of the fourth capacitor C1 is to allow the AC signal to pass through and isolate the DC signal, that is, to allow the high-frequency square wave signal to flow to the conductor to be detected RC, preventing the DC current in the circuit to be detected where the conductor to be detected RC is located from flowing back to the virtual connection detection circuit, thereby causing significant interference to the detection result of the virtual connection detection circuit) to the conductor to be detected RC, passes through the conductor to be detected RC, and enters the bandpass filter 603; the bandpass filter is composed of a high-pass filter circuit and a low-pass filter circuit. The filtering circuit is composed of a filter circuit, which is used to filter out the target frequency band signal (based on the band-pass filter to filter out interference signals such as low-frequency DC and high-frequency noise, leaving the target frequency band signal). The target frequency band signal can adjust the frequency band range by configuring component parameters. The signal range should include the frequency value of the aforementioned high-frequency square wave signal; the peak detection module 604 is composed of a first diode and a first capacitor C6, which is used to convert the target frequency band signal into a DC signal (the value of the DC signal is approximately equal to the positive half-cycle peak value of the AC square wave signal in the target frequency band); the virtual connection alarm module 605 is composed of a comparator U3, a voltage divider RP, a first resistor R5 and an indicator. The indicator is used to indicate whether there is a virtual connection. For example, when the indicator is a light-emitting device, the light-emitting device includes a light-emitting element and a protective resistor. When the light-emitting element emits light, it is determined that there is a virtual connection fault. If it does not emit light, the detection continues. If the wire RC to be detected is in a virtual connection state, the virtual connection resistance it generates will cause a voltage drop in the circuit. At this time, the monitored voltage value will be lower than the voltage threshold set by the virtual connection alarm module 605, causing the light-emitting diode LED1 to light up. If the monitored voltage value is higher than the voltage threshold, it is considered that the wire RC to be detected is in a normal state.

[0082] In order to make the technical solution of this application clearer, Figure 2 The schematic diagram of the virtual connection detection circuit shown is used as an example.

[0083] Exemplarily, the power module 601 composed of the battery S1 and the voltage regulator U1 outputs a voltage of 3.3V, the resistance of the fourth resistor R1 is 4700Ω, the resistance of the fifth resistor R2 is 4700Ω, the resistance of the second resistor R3 is 10000Ω, the resistance of the third resistor R4 is 10Ω, the resistance of the first resistor R5 is 100Ω, the resistance of the protection resistor R6 is 1000Ω, the capacitance of the fourth capacitor C1 is 100nF, the capacitance of the second capacitor C2 is 100nF, the capacitance of the fifth capacitor C3 is 10nF, the capacitance of the sixth capacitor C4 is 10nF, the capacitance of the third capacitor C5 is 1uF, the capacitance of the first capacitor C6 is 1uF, and the voltage divider RP is 10000Ω. The voltage divider RP is used to adjust the positive input voltage V3 of the non-inverting input terminal of the comparator U3 to 0.6V, and the voltage drop VD1 through the first diode D1 is 0.3V. Assuming that the voltage does not decay after passing through timer U2, the resistance of the wire RC to be tested when there is no loose connection 0Ω, the resistance of the wire RC to be detected when the connection is virtual The resistance is 1000Ω. The voltage divider RP may be a potentiometer. The indicator is a light emitting device.

[0084] Based on the known conditions, the frequency of the high-frequency square wave signal emitted by the high-frequency oscillation module can be calculated as:

[0085]

[0086] Indicates the high-frequency square wave signal emitted by the high-frequency oscillation module. represents the resistance value of the fourth resistor, represents the resistance value of the fifth resistor, Indicates the capacitance of the fifth capacitor.

[0087] Since the high level of the high frequency square wave signal emitted by the U2_3-OUT pin of the timer U2 in the high frequency oscillation module is approximately equal to the voltage connected to the U2_8-VCC pin of the timer U2, then , Represents the output voltage of timer U2.

[0088] Based on the known conditions, the cutoff frequencies of the high-pass filter circuit and the low-pass filter circuit can be calculated as follows:

[0089]

[0090]

[0091] From this we can see that the passband frequency range of the bandpass filter is:

[0092]

[0093] It can be seen from this that the high-frequency square wave signal (frequency) generated by the high-frequency oscillation module ) can pass through a bandpass filter.

[0094] When there is a virtual connection fault in the wire to be detected, the equivalent voltage divider resistor that forms a voltage divider relationship with R5 in the virtual connection detection circuit is:

[0095]

[0096] in, is the equivalent voltage divider resistor, Indicates the resistance of the wire to be tested. Expressed as the impedance of the fourth capacitor C1, is the equivalent impedance of the low-pass filter circuit, is the equivalent impedance of the high-pass filter circuit.

[0097] It can be calculated as follows:

[0098]

[0099] in, Indicates the capacitance of the fourth capacitor.

[0100] It can be calculated as follows:

[0101]

[0102] represents the resistance of the third resistor, j represents the imaginary unit, Indicates the capacitance of the third capacitor.

[0103] right Modulo, we get:

[0104]

[0105] Since the frequency of the high-frequency square wave signal emitted by the high-pass filter Much greater than its cutoff frequency ,Right now, , the equivalent impedance brought by the high-pass filter can be ignored, so .

[0106] Therefore, when the virtual connection is not established, the first equivalent voltage-dividing resistor in the virtual connection detection circuit forms a voltage-dividing relationship with the first resistor R5. for: Based on the voltage division principle, the voltage at the negative input of the comparator U3 is for: in, It represents the voltage at the negative input terminal of the comparator U3 when it is not connected. represents the voltage across the first resistor R5, Indicates the output voltage of the U2_3-OUT pin of the timer U2, represents the voltage across the first diode, represents the resistance value of the first resistor, Indicates the first equivalent voltage divider resistance when there is no loose connection.

[0107] Therefore, when the wire to be detected is not loosely connected:

[0108]

[0109] in: The voltage threshold value is adjusted by the voltage divider RP on the positive input terminal of the comparator U3. For the comparator U3, the negative input terminal voltage is greater than the positive input terminal voltage at this time, and the output terminal voltage is equal to the ground voltage, that is, 0V. At this time, the light-emitting diode LED1 does not emit light.

[0110] When the connection is virtual, the second equivalent voltage-dividing resistor forms a voltage-dividing relationship with the first resistor R5 in the virtual connection detection circuit. for: = = = Based on the voltage division principle, the voltage at the negative input of the comparator U3 when the virtual connection is established can be obtained as follows: for:

[0111] Therefore, when the wire to be detected is loosely connected:

[0112]

[0113] For the comparator U3, at this time, the positive input terminal voltage is greater than the negative input terminal voltage, and its output terminal voltage is equal to the VCC voltage, that is, 3.3V. At this time, the light-emitting diode LED1 is powered on and emits light, realizing a virtual connection alarm.

[0114] The technical solution of this application has the following beneficial effects:

[0115] This invention patent solves the pain points of wiring during bench testing, namely, the low wiring efficiency and reliability. It considers using a virtual connection detection integrated circuit to compensate for the defect of fast wiring terminals that cannot determine whether there is a virtual connection during wiring. It combines the wiring efficiency advantages of fast wiring terminals with the wiring reliability advantages of virtual connection detection technology, effectively avoiding signal distortion, transmission interruption and other possible safety hazards caused by virtual connection in the main circuit;

[0116] This invention patent takes into account the problem that the original main circuit DC signal may interfere with the virtual connection detection circuit during the bench test. It cleverly uses the principles of high-frequency injection and bandpass filtering to block the DC signal, screen the target frequency band signal emitted by the virtual connection detection circuit, and then uses the peak detection principle to process the target frequency band signal that passes through into a DC signal, providing DC support for the virtual connection alarm module, thereby improving the robustness of the virtual connection detection integrated circuit.

[0117] The patent of this invention also takes circuit adaptability into consideration. By configuring a potentiometer, the user can adjust the minimum alarm threshold of the virtual connection detection voltage according to the actual situation of the circuit, making the adaptability of the virtual connection detection circuit more flexible.

[0118] The present invention reduces manufacturing costs and physical space occupation while ensuring functional integrity and performance, which is particularly critical for integrating equipment into small quick-connect terminals, meeting the requirements of compact design without adding additional cost burden.

[0119] The present application also provides a virtual connection detection device, such as Figure 6 , which is a schematic diagram of a loose connection detection device provided in an embodiment of the present application. The loose connection detection device includes a wire fixing device 701 and a loose connection detection circuit 702. The wire fixing device 701 and the loose connection detection circuit 702 can be disposed within a housing, which can be made of flame-retardant nylon. The wire fixing device 701 is used to secure the wire to be detected, and the loose connection detection circuit 702 can be the loose connection detection circuit described in the previous embodiment.

[0120] This application does not specifically limit the specific structure of the wire fixing device.

[0121] The present application also provides a method for detecting a virtual connection, which is applied to any optional virtual connection detection circuit in the aforementioned embodiments. The method can be executed by a processing device, and includes:

[0122] S701: The processing device obtains indication content of the indicator.

[0123] The processing device may obtain the indication content of the indicator through a sensor, or may determine the indication content by receiving a signal sent by the indicator. The indication content may be a flashing light (for example, the corresponding indicator is a light emitting diode).

[0124] S702: The processing device determines a detection result of the virtual contact detection according to the instruction content.

[0125] After the processing device determines the indication content, it can determine the detection result corresponding to the indication content based on the pre-set mapping relationship between content and results. For example, if the indication content is a flashing light, the corresponding inspection result is a loose connection problem.

[0126] The above description is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed in the present application should be included in the protection scope of the present application.

Claims

1. A virtual connection detection circuit, characterized in that: The circuit includes: a comparator, a first resistor, a voltage divider and an indicator; The positive input terminal of the comparator is used to connect to the moving point of the voltage divider, the first terminal of the voltage divider is used to connect to the power supply voltage, the second terminal of the voltage divider is used to be grounded, and the power supply voltage is used to power the voltage divider and the comparator; The negative input terminal of the comparator is used to connect the first end of the first resistor, the second end of the first resistor is grounded, the negative input terminal of the comparator is also used to connect the first end of the wire to be detected, and the second end of the wire to be detected is used to connect the input voltage; The output end of the comparator is used to connect to the indicator, and the indicator is used to indicate the detection result; Among them, after the virtual connection occurs, the input voltage is divided by the first resistor and the wire to be detected, the voltage across the first resistor decreases, and the negative input voltage of the negative input terminal of the comparator is less than the positive input voltage.

2. The virtual connection detection circuit according to claim 1, characterized in that: The circuit further comprises: a peak detection circuit and a filtering circuit; The output end of the peak detection circuit is connected to the first end of the first resistor, the input end of the peak detection circuit is connected to the output end of the filter circuit, and the input end of the filter circuit is connected to the first end of the wire to be detected; The filtering circuit is used to filter out interference signals and output target frequency band signals; The peak detection circuit is used to convert the target frequency band signal into a DC signal.

3. The virtual connection detection circuit according to claim 2, wherein: The peak detection circuit includes a first diode and a first capacitor; The first end of the first capacitor is connected to the cathode of the first diode, the first end of the first capacitor is connected to the negative input end of the comparator, and the second end of the first capacitor is grounded; the anode of the first diode is used to connect to the filter circuit.

4. The virtual connection detection circuit according to claim 3, characterized in that: The filtering circuit includes a high-pass filtering circuit and a low-pass filtering circuit; The high-pass filter circuit includes a second capacitor and a second resistor, and the low-pass filter circuit includes a third capacitor and a third resistor; The first end of the second capacitor is connected to the first end of the wire to be detected, the second end of the second capacitor is connected to the first end of the second resistor, and the second end of the second resistor is grounded; The first end of the third resistor is connected to the second end of the second capacitor, the second end of the third resistor is connected to the first end of the third capacitor, and the second end of the third capacitor is grounded; The second end of the third resistor is connected to the anode of the first diode.

5. The virtual connection detection circuit according to claim 1, wherein: The circuit further includes a fourth capacitor; The first end of the fourth capacitor is connected to the second end of the wire to be detected, and the second end of the fourth capacitor is used to connect to the power supply voltage.

6. The virtual connection detection circuit according to claim 1, characterized in that: When the moving point of the voltage divider moves toward the first end of the voltage divider, the resistance between the moving point of the voltage divider and the first end of the voltage divider becomes smaller; when the moving point of the voltage divider moves toward the second end of the voltage divider, the resistance between the moving point of the voltage divider and the first end of the voltage divider becomes larger.

7. The virtual connection detection circuit according to claim 6, characterized in that: When the voltage at the non-inverting input terminal of the comparator is greater than the voltage at the negative input terminal of the comparator, the output terminal of the comparator outputs the power supply voltage.

8. The virtual connection detection circuit according to any one of claims 1 to 7, characterized in that: The indicator includes a light-emitting device, a sound-emitting device or a vibration device.

9. A virtual connection detection device, characterized in that: The invention comprises a wire fixing device and the virtual connection detection circuit according to any one of claims 1 to 8.

10. A virtual connection detection method, characterized in that: Applied to the virtual connection detection circuit according to any one of claims 1 to 8, the method comprises: Get the indication content of the indicator; According to the instruction content, a detection result of the virtual connection detection is determined.

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