Signal source protection device and signal source

Abstract

The utility model discloses a signal source protection device which comprises a signal detection circuit, the input end of the signal detection circuit is connected with a signal interface protection circuit, and the output end of the signal detection circuit is connected with a signal indication circuit. The signal interface protection circuit is used for clamping an input high-voltage signal; and the signal detection circuit comprises a window comparator and a logic gate circuit, and is used for detecting the voltage signal which is input in real time and clamped by the signal protection circuit and the electric quantity of the battery, and outputting a detection result to the signal indication circuit. According to the utility model, high-voltage signals are clamped, and signals with rated amplitude and frequency are allowed to pass through, so that a signal source is protected, attenuation of signals accessed to equipment to be metered is avoided, and the detection precision is ensured; the problem that a signal source interface is damaged due to the fact that a high-voltage excitation signal output by to-be-metered equipment is connected into a signal source in series is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of sound wave equipment measurement, specifically relates to a signal source protection device and signal source. BACKGROUND

[0002] When measuring nondestructive testing equipment such as metrology sound wave detector and ultrasonic flaw detector, the electrical performance of the detected equipment needs to be calibrated by a signal source, and the connection diagram is as shown in Figure 10 The transmitting end (T) of the detected equipment is connected to the external trigger interface of the signal source through the external trigger protection device, and the signal source output interface is connected to the receiving end (R) of the detected equipment.

[0003] In actual detection, the transmitting and receiving ends of the detected equipment are often marked reversely or wired incorrectly, which leads to the connection of the transmitting end of the detected equipment to the output end of the signal source, and the high-voltage pulse of the output end of the detected equipment damages the signal source. SUMMARY

[0004] To solve the problem of interface damage of the signal source caused by the high-voltage excitation signal output by the equipment to be measured, the utility model provides a signal source protection device, which clamps the high-voltage signal and allows the signal with rated amplitude and frequency to pass through, thereby protecting the signal source and avoiding the attenuation of the signal input into the equipment to be measured, and ensuring the detection accuracy.

[0005] According to one aspect of the utility model, a signal source protection device is provided, which comprises a signal detection circuit, the input end of the signal detection circuit is connected to a signal interface protection circuit, and the output end is connected to a signal indication circuit; the signal interface protection circuit is used for clamping the input high-voltage signal; the signal detection circuit comprises a window comparator and a logic gate circuit, which is used for detecting the voltage signal clamped by the signal protection circuit and the battery capacity input in real time, and outputting the detection result to the signal indication circuit.

[0006] Optionally, the signal indication circuit comprises a logic gate circuit and a triode, which is used for realizing the different color display and shutdown of the signal indication lamp and the capacity indication lamp.

[0007] Optionally, the signal interface protection circuit comprises a transient suppression diode in parallel.

[0008] Optionally, the window comparator has two paths, and each path of the window comparator comprises two voltage comparators, which is used for forming a rated voltage threshold interval and outputting two level signals.

[0009] Optionally, the signal source protection device further comprises a power supply circuit.

[0010] Optionally, the power supply circuit is connected to an 8.4V / 3A charger.

[0011] Optionally, the power supply circuit is configured with a charging interface protection circuit, which is realized by MOS tubes, triodes and voltage stabilizing tubes.

[0012] Optionally, the signal source protection device is connected with the signal source and the equipment to be detected respectively through BNC connectors.

[0013] Optionally, the signal source protection device is further configured with a switch for protecting the switch of the device itself.

[0014] According to an aspect of the utility model specification, a signal source is provided with the signal source protection device.

[0015] Compared with the prior art, the utility model has the advantages of:

[0016] The utility model discloses a signal source protection device between the signal source and the equipment to be detected, solves even if the equipment to be detected output instantaneous or periodic high voltage pulse signal, after signal source protection device, will not damage the signal source, simultaneously gives high voltage early warning prompt, and when the signal source output set frequency and amplitude signal, can be received normally by the equipment to be detected, and the signal source output signal is not distorted after the protection device. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, below, the drawings used in the embodiment or prior art description will be simply introduced, and obviously, the drawings in the following description are some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creative labor.

[0018] Figure 1 The structural schematic diagram of a signal source protection device provided by the utility model embodiment.

[0019] Figure 2 The hardware connection schematic diagram of a signal source protection device provided by the utility model embodiment.

[0020] Figure 3 The schematic diagram of a signal interface protection circuit provided by the utility model embodiment.

[0021] Figure 4 The schematic diagram of a window comparator circuit provided by the utility model embodiment.

[0022] Figure 5 The schematic diagram of a logic and gate circuit provided by the utility model embodiment.

[0023] Figure 6 (a)-(b) are the schematic diagram of a signal indicating lamp circuit provided by the utility model embodiment.

[0024] Figure 7 A schematic diagram of the power supply circuit provided for an embodiment of this utility model.

[0025] Figure 8 A schematic diagram of the charging interface protection circuit provided in an embodiment of this utility model.

[0026] Figure 9 A connection diagram of the signal source protection device provided in an embodiment of this utility model.

[0027] Figure 10 This is a connection diagram for testing existing equipment. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. In addition, the technical features of the various embodiments or individual embodiments provided by this utility model can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0029] Please see Figure 1 and Figure 2The signal source protection device provided by this utility model mainly consists of a signal input / output interface, a signal interface protection circuit, a signal detection circuit, and a signal indication circuit. The signal input / output interface is a BNC female connector, connected to the signal interface protection circuit via a 2-core shielded cable. The signal interface protection circuit primarily clamps high-voltage signals while allowing signals of rated amplitude and frequency to pass through. The signal detection circuit primarily detects the input signal and battery level, outputting the detection results to a signal indication unit for controlling relevant indicator lights in the signal indication circuit. The signal indication circuit includes a signal indicator light and a battery level indicator light. When the input signal amplitude is within the allowable range, the signal indicator light is green. If there is a pulsed high-voltage input, the signal indicator light flashes red and green alternately. At this time, note that the current signal channel of the device being measured has a high-voltage output; please adjust the relevant settings of the device and re-measure. When the battery level of the signal source protection device is higher than the safety threshold, the battery level indicator light is green; when it is lower than the safety threshold, it is red. When the battery level indicator light is red, please charge the signal source protection device promptly. It is best not to measure during charging to avoid affecting the testing progress.

[0030] During measurement, use two double-ended BNC male connectors. Connect one end of one cable to the acoustic signal interface and the other end to the signal input interface of the signal source protection device. Connect the other double-ended BNC male connector to the signal channel of the signal source or the trigger channel on the back and the other end to the signal output interface of the signal source protection device. During the test, carefully observe the signal and power indicator lights of the signal source protection device and perform the corresponding operations according to the indicator light colors.

[0031] Please see Figure 3 The signal interface protection circuit mainly consists of parallel low-capacitance TVS diodes, used to clamp the input signal. It allows voltage signals of rated amplitude to pass directly while clamping high-voltage signals to a safe range to prevent damage to the signal source interface. This embodiment uses two extremely low-capacitance TVS diodes, PJGBLC03, connected in parallel. This allows signals with a peak-to-peak value of 10V Vpp to pass without loss, while clamping voltage signals higher than 10V Vpp to 10V Vpp, ensuring the signal source channel is not damaged by high voltage.

[0032] Specifically, the signal interface protection circuit is used to clamp the input signal, allowing the voltage signal of the rated amplitude to pass directly, while clamping the high voltage signal to a safe range to avoid damage to the signal source interface. In this embodiment, a TVS diode with extremely low capacitance, PJGBLC03C_R1_00001 from PANJIT, is selected to clamp the pulse high voltage signal. The maximum internal parasitic capacitance of this TVS diode is 3pF, which can ensure that the signal in the frequency range to be measured will not be attenuated when it passes through the signal interface protection circuit.

[0033] Please see Figure 4The signal detection circuit mainly consists of window comparators and logic gate circuits. It is used to detect the real-time input voltage signal and battery level, and input the detection results to the signal indication circuit to control the signal indicator and battery level indicator. Each window comparator is composed of two voltage comparators, forming a rated voltage threshold range, and outputs two TTL level signals. If the input signal is within the upper and lower threshold range of the window comparator, both voltage comparators output a high level; conversely, if the input signal is higher than the maximum voltage threshold or lower than the minimum voltage threshold, the voltage comparator outputs a low level. Preferably, battery level detection can use only one voltage comparator, i.e., if the real-time voltage is higher than the set safety threshold, the voltage comparator outputs a high level; otherwise, it outputs a low level.

[0034] To enable real-time detection of input signals and battery power, this embodiment uses a TI LM339 voltage comparator to form a window comparator. This allows setting safe threshold ranges for the input signal and battery power. Within these safe threshold ranges, the corresponding indicator light will illuminate green. When the signal indicator light flashes red and green alternately, it indicates that the input signal is a pulsed high-voltage signal. Please check if the parameters of the device being measured are set correctly and ensure that the current metering channel is in receiving mode. When the power indicator light is red, please charge the battery promptly.

[0035] Specifically, in the signal detection circuit, each window comparator consists of two sets of voltage comparators. These two sets of voltage comparators output two TTL level signals, which are then passed through a two-input AND gate to output a single TTL level signal, which is input to the signal indicator circuit to control the on / off state of the dual-color LED. In this embodiment, the logic gate chip used is the TI single-channel dual-input AND gate chip SN74AHC1G08, with an operating voltage range of 2-5.5V, and all input interfaces support Schmitt trigger operation.

[0036] Please see Figure 5 After detecting the real-time input signal, the window comparator outputs two TTL level signals. These two TTL level signals are then connected to a two-input AND gate to control the subsequent signal indication circuit. The control principle is as follows: When the amplitude of the real-time input signal is within the upper and lower threshold range of the window comparator, both voltage comparators output a TTL high level. Through the two-input AND gate, the output signal remains a TTL high level. When the real-time input signal is greater than the upper threshold or lower than the lower threshold, the two voltage comparators output TTL level signals of different heights. Through the two-input AND gate, the output signal is a TTL low level. That is, when the input voltage signal amplitude is within the safe threshold range, the subsequent dual-color indicator light is green; when it is higher than the highest safe threshold or lower than the lowest safe threshold, the subsequent dual-color indicator light is red. This achieves real-time signal detection and provides prompts.

[0037] Please seeFigure 6 The signal indication circuit consists of logic gates and transistors, used to control the different colors displayed and turned off of the signal indicator and power indicator. The signal indicator and power indicator are common-anode dual-color indicators used to indicate the input signal and battery status. In the diagram, the Schmitt trigger inverter is connected to the output of the preceding signal detection circuit, and the output signal is connected to the subsequent NPN transistor. Its main function is to ensure that the red and green dual-color indicator lights do not light up or turn off simultaneously, i.e., the two indicator lights are mutually exclusive, thus ensuring the normal operation of the indicator lights.

[0038] Please see Figure 7 The signal source protection device allows voltage signals with an amplitude of 10V Vpp to pass through, meaning the maximum input signal is ±5V. Based on this requirement, the signal detection circuit that performs real-time detection of the input voltage signal is powered by ±12V to ensure accurate detection of the input signal and to reserve some margin.

[0039] Please see Figure 8 Because the real-time power consumption of the signal source protection device is extremely low, an 8.4V / 3AH battery is selected for power supply. In order to protect the charging interface and the subsequent circuit, and to ensure that there is no voltage at the charging interface when the charger is not connected, this design uses two MOSFETs combined with transistors and Zener diodes to form a charging interface protection circuit. At the same time, if the charging interface is connected to a charger with a voltage higher than 8.4V for a short time, the subsequent circuit will not be damaged.

[0040] Specifically, the signal source protection device mainly consists of a ±12V signal detection circuit and a 3.3V system power supply, both of which have very low load power consumption. The ±12V signal detection circuit has a 3W power supply reserved, and the Mornsun WRA0512S-3WR2 power module is selected. In addition, for the power supply of the main control unit and peripheral conditioning circuit, a TI 3.3V ultra-low noise LDO is selected for power supply, with power supply noise less than 20uV.

[0041] Please see Figure 9 The process of using this utility model includes:

[0042] 1. During normal testing, first connect the signal output channel of the signal source to the signal input interface of the signal source protection device through a BNC connector cable, and connect the test channel of the device under test to the signal output interface of the protection device through a BNC connector cable.

[0043] 2. Press the switch of the protection device to power it on. Under normal circumstances, both the signal and power indicator lights will be green. Regarding the signal indicator light, when the device under test outputs a high-voltage pulse signal with a peak-to-peak value exceeding ±2.6V, the signal indicator light will be red. When the device under test outputs a periodic high-voltage pulse signal, the signal indicator light will flash red and green alternately. Therefore, when the signal indicator light is red or flashing red and green alternately, it indicates that the device under test has a transient or periodic high-voltage signal output. In this case, please turn off the device under test immediately. The maximum allowable peak-to-peak value of the signal for the protection device is ±4.3V. If this value is exceeded, the signal waveform will be clamped at ±4.3V, and the waveform will be clipped. The power indicator light mainly displays the battery level. When the battery level is higher than 6V, the power indicator light will be green; when it is lower, it will be red. When the power indicator light is red, please charge the protection device to prevent the device from malfunctioning.

[0044] 3. After the protection device is turned on normally, turn on the device under test. When both indicator lights on the protection device are green, the signal source can be turned on and the signal source output channel can be opened to perform normal index testing.

[0045] 4. The signal source protection device comes standard with an 8.4V / 3A charger. When the power indicator light is red, please charge the device in time. Note that the protection device should not be used while it is charging to avoid abnormal test indicators due to the intrusion of charger ripple noise.

[0046] 5. During use, never plug or unplug while the circuit is energized to avoid damaging the protection device.

[0047] 6. After use, please remember to turn off the protective device.

[0048] Based on the same inventive concept as the foregoing embodiments, this utility model also provides a signal source configured with the aforementioned signal source protection circuit. When using the signal source to test a device under test, the configured signal source protection device can protect the signal source and prevent damage to it.

[0049] In summary, this invention incorporates a signal source protection device between the signal source and the device under test. This ensures that even if the device under test outputs instantaneous or periodic high-voltage pulse signals, the signal source will not be damaged after passing through the protection device. At the same time, it provides a high-voltage warning. When the signal source outputs a signal with a set frequency and amplitude, it can be normally received by the device under test. Based on prior communication, signals up to 10V are allowed to pass through, while signals above 10V are directly shut off from the transmission path. Furthermore, the signal output from the signal source is not distorted after passing through the protection device.

[0050] It should be understood that any details not described in this utility model can be considered as conventional technology in the field.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of this utility model.

Claims

1. A signal source protection device, characterized in that, The system includes a signal detection circuit, the input of which is connected to a signal interface protection circuit, and the output of which is connected to a signal indicator circuit. The signal interface protection circuit is used to clamp the input high-voltage signal. The signal detection circuit includes a window comparator and logic gate circuits, which are used to detect the voltage signal and battery power that are clamped by the signal protection circuit in real time, and output the detection results to the signal indicator circuit.

2. The signal source protection device according to claim 1, characterized in that, The signal indicator circuit includes logic gate circuits and transistors, used to display and turn off the signal indicator and power indicator in different colors.

3. The signal source protection device according to claim 1, characterized in that, The signal interface protection circuit includes transient suppression diodes connected in parallel.

4. The signal source protection device according to claim 1, characterized in that, The window comparator has two channels, each of which includes two voltage comparators to form a rated voltage threshold range and output two level signals.

5. The signal source protection device according to claim 1, characterized in that, The signal source protection device also includes a power supply circuit.

6. The signal source protection device according to claim 5, characterized in that, The power supply circuit is connected to an 8.4V / 3A charger.

7. The signal source protection device according to claim 5, characterized in that, The power supply circuit is equipped with a charging interface protection circuit, which is implemented using MOSFETs, transistors, and Zener diodes.

8. The signal source protection device according to claim 1, characterized in that, The signal source protection device is connected to the signal source and the device under test via BNC connectors.

9. The signal source protection device according to claim 1, characterized in that, The signal source protection device is also equipped with a switch for protecting the device itself.

10. A signal source, characterized in that, It is equipped with the signal source protection device as described in any one of claims 1-9.

Images