Oscilloscope probe
By introducing voltage sampling, comparison and switching circuits into the oscilloscope probe, combined with the electrostatic suppression circuit, the damage caused by voltage abnormalities and static electricity when measuring high-speed signals is solved, and the safety and cost-effectiveness of the equipment are achieved.
Patent Information
- Application Number
- CN202420449206.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-07
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2034-03-07
AI Technical Summary
When measuring high-speed data signals, the oscilloscope probe is prone to damage due to abnormal levels of unknown signals or high static electricity, and the cost is high, so the prior art is difficult to effectively prevent damage.
An oscilloscope probe is designed, including a voltage sampling circuit, a voltage comparison circuit and a switching circuit. By collecting the detection voltage of the probe pin, comparing the voltage signal with a preset threshold. If the threshold is exceeded, the connection will be cut off to prevent excessive signal input, and equipped with The electrostatic suppression circuit prevents surge static electricity.
Effectively prevent oscilloscope probes from being damaged by excessive signal or static electricity, reducing maintenance and replacement costs, improving the service life of the equipment and measuring accuracy.
Smart Images
Figure CN222319034U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of oscilloscopes, and in particular to an oscilloscope probe. Background Art
[0002] As high-end oscilloscopes for measuring high-speed data signals are constantly updated, the accuracy of the probes used with the oscilloscopes is becoming more and more precise, with voltage accuracy reaching the mV level and measurement bandwidths as high as 25G, 50G or even higher. Of course, the cost will also increase. The more precise the probe, the stricter the signal range to be measured, so that the probe can only measure high-speed signals with high frequency and small voltage amplitude. Signals that exceed the voltage amplitude standard can easily damage the oscilloscope probe. If the measuring equipment leaks abnormally or high static electricity is accidentally introduced during the measurement of the level of an unknown signal, and the tester cannot promptly detect the abnormal level that exceeds the probe voltage limit, the oscilloscope probe is easily damaged, resulting in high cost losses. Utility Model Content
[0003] In view of the above problems, it is necessary to provide an oscilloscope probe to prevent damage to the oscilloscope probe.
[0004] The present application provides an oscilloscope probe, including a probe needle, and the oscilloscope probe also includes: a voltage sampling circuit, the input end of the voltage sampling circuit is connected to the probe needle, the voltage sampling circuit is used to collect the detection voltage of the probe needle, and output a corresponding voltage signal according to the detection voltage; a voltage comparison circuit, the voltage comparison circuit is connected to the output end of the voltage sampling circuit, the voltage comparison circuit is used to receive the voltage signal and compare the voltage value of the voltage signal with a preset voltage threshold, when the voltage value of the voltage signal exceeds the preset voltage threshold, output an enable signal; and a switch circuit, the switch circuit is connected between the probe needle and the input interface of the oscilloscope, and is connected to the output end of the voltage comparison circuit, the switch circuit is used to cut off the connection between the probe needle and the input interface when receiving the enable signal.
[0005] In one embodiment, the oscilloscope probe further includes a display circuit, which is connected to the voltage sampling circuit or the voltage comparison circuit, and is used to receive a voltage signal and display a voltage value of the voltage signal.
[0006] In one embodiment, the oscilloscope probe also includes a warning circuit, which is connected to the voltage comparison circuit. When the voltage value of the voltage signal exceeds a preset voltage threshold, the voltage comparison circuit sends a warning signal to the warning circuit. The warning circuit is used to indicate that the voltage value of the voltage signal exceeds the preset voltage threshold according to the warning signal.
[0007] In one embodiment, the oscilloscope probe further includes an electrostatic suppression circuit, which is connected to the probe needle and is used to suppress surge static electricity generated by the probe needle.
[0008] In one embodiment, the electrostatic suppression circuit includes a suppression diode, a filter capacitor and a filter resistor, the first end of the suppression diode is connected to the probe needle, the second end of the suppression diode is connected to the first end of the filter capacitor and the first end of the filter resistor, and the second end of the filter capacitor and the second end of the filter resistor are grounded.
[0009] In one embodiment, the voltage sampling circuit includes: a voltage divider module, connected to the probe needle, the voltage divider module is used to divide the detection voltage of the probe needle and output a voltage divider signal; an amplification module, connected to the voltage divider module, the amplification module is used to receive the voltage divider signal and amplify the voltage divider signal; and an analog-to-digital conversion module, connected to the amplification module, the analog-to-digital conversion module is used to receive the amplified voltage divider signal, and perform analog-to-digital conversion on the voltage divider signal to obtain a voltage signal, wherein the voltage signal is a digital signal.
[0010] In one embodiment, the voltage divider module includes a first voltage divider resistor, a second voltage divider resistor and a third voltage divider resistor, the first end of the first voltage divider resistor is connected to the probe needle, the second end of the first voltage divider resistor is connected to the first end of the second voltage divider resistor, the second end of the second voltage divider resistor is connected to the first end of the third voltage divider resistor, and the second end of the third voltage divider resistor is grounded; the amplification module includes a comparison operational amplifier, the first input end of the comparison operational amplifier is connected to the first end of the second voltage divider resistor, the second input end of the comparison operational amplifier is connected to the second end of the second voltage divider resistor, and the comparison operational amplifier is used to receive the voltage across the second voltage divider resistor and amplify the voltage to obtain the voltage divider signal and then output it; the analog-to-digital conversion module includes an analog-to-digital converter, the input end of the analog-to-digital converter is connected to the output end of the comparison operational amplifier, the output end of the analog-to-digital converter is connected to the voltage comparison circuit, and the analog-to-digital converter is used to perform analog-to-digital conversion on the amplified voltage divider signal to obtain a voltage signal.
[0011] In one embodiment, the voltage comparison circuit includes a comparison module and a storage module. The comparison module is connected to the output end of the analog-to-digital conversion module, the storage module and the switching circuit. The comparison module is used to receive a voltage signal and a preset voltage threshold stored in the storage module, compare the voltage value of the voltage signal with the preset voltage threshold, and output an enable signal when the voltage value of the voltage signal exceeds the preset voltage threshold.
[0012] In one embodiment, the comparison module includes a decoder, and the storage module includes a register.
[0013] In one embodiment, the oscilloscope probe also includes a reset switch, a first end of the reset switch is connected to a reset end of a decoder, and a second end of the reset switch is grounded; when the reset end of the decoder receives a low-level signal, the decoder outputs a conduction signal to the switch circuit, and the switch circuit is also used to conduct the connection between the probe pin and the input interface when receiving the conduction signal.
[0014] In the oscilloscope probe of the embodiment of the present application, the detection voltage of the probe needle is collected by the voltage sampling circuit, and the corresponding voltage signal is output according to the detection voltage. The voltage comparison circuit compares the voltage value of the voltage signal with the preset voltage threshold. When the voltage value of the voltage signal exceeds the preset voltage threshold, an enable signal is output, and the switch circuit cuts off the connection between the probe needle and the input interface of the oscilloscope when receiving the enable signal. In this way, when the oscilloscope probe of the embodiment of the present application is used to measure the signal, if the voltage value of the measured signal is greater than the preset voltage threshold, the voltage comparison circuit can output an enable signal to enable the switch circuit to cut off the connection between the probe needle and the input interface of the oscilloscope, thereby preventing the probe needle from inputting an excessively large signal and causing damage to the oscilloscope probe. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 Schematic diagram of a module of an oscilloscope probe according to an embodiment of the present application.
[0016] Figure 2 A schematic diagram of a module of an oscilloscope probe according to an embodiment of the present application.
[0017] Figure 3 A schematic diagram of a module of an oscilloscope probe according to an embodiment of the present application.
[0018] Figure 4 A schematic diagram of a module of an oscilloscope probe according to an embodiment of the present application.
[0019] Figure 5 Schematic diagram of the internal circuit of the oscilloscope probe according to the embodiment of the present application.
[0020] Main component symbols
[0021] Oscilloscope Probe 100
[0022] Probe needle 10
[0023] Input interface SMA
[0024] Voltage sampling circuit 20
[0025] Voltage divider module 21
[0026] The first voltage dividing resistor R1
[0027] The second voltage dividing resistor R2
[0028] The third voltage dividing resistor R3
[0029] Amplification module 22
[0030] Comparator Operational Amplifier U1
[0031] Analog-to-digital conversion module 23
[0032] Analog-to-digital converter U2
[0033] Voltage comparison circuit 30
[0034] Comparison module 31
[0035] Decoder U3
[0036] Storage module 32
[0037] Register U4
[0038] Switching circuit 40
[0039] Isolating switch K1
[0040] Display circuit 50
[0041] Display 51
[0042] Digital display tube 52
[0043] Warning circuit 60
[0044] Warning switch G0
[0045] Warning light D1
[0046] Static Electricity Suppression Circuit 70
[0047] Suppression diode D2
[0048] Filter capacitor C1
[0049] Filter resistor R4
[0050] Reset switch K2
[0051] Sampling amplifier circuit 80
[0052] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION
[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0054] It should be noted that when an element is referred to as being "electrically connected" to another element, it may be directly on the other component or there may be an intermediate element. When an element is considered to be "electrically connected" to another element, it may be a contact connection, for example, a wire connection, or a contactless connection, for example, a contactless coupling.
[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.
[0056] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.
[0057] See also Figure 1 An embodiment of the present application provides an oscilloscope probe 100 , which includes a probe needle 10 , a voltage sampling circuit 20 , a voltage comparison circuit 30 and a switch circuit 40 .
[0058] The probe needle 10 is used to connect to a test point of a circuit / device under test.
[0059] The input end of the voltage sampling circuit 20 is connected to the probe needle 10 . The voltage sampling circuit 20 is used to collect the detection voltage of the probe needle 10 and output a corresponding voltage signal according to the detection voltage.
[0060] It can be understood that the detection voltage is the voltage of the test point to which the probe needle 10 is connected.
[0061] The voltage comparison circuit 30 is connected to the output end of the voltage sampling circuit 20, and is used to receive a voltage signal and compare the voltage value of the voltage signal with a preset voltage threshold. When the voltage value of the voltage signal exceeds the preset voltage threshold, an enable signal is output.
[0062] In some embodiments, the preset voltage threshold may be the maximum voltage value allowed to be input by the oscilloscope. Alternatively, the preset voltage threshold may be a value related to the maximum voltage value allowed to be input by the oscilloscope. In this case, the preset voltage threshold may be determined according to the sampling method of the voltage sampling circuit 20.
[0063] The switch circuit 40 is connected between the probe needle 10 and the input interface SMA of the oscilloscope, and is connected to the output end of the voltage comparison circuit 30. The switch circuit 40 is used to cut off the connection between the probe needle 10 and the input interface SMA when receiving an enable signal. The switch circuit 40 may include a controllable switch, such as a relay, a power switch tube, a contactor, and the like.
[0064] In the oscilloscope probe 100 of the embodiment of the present application, the detection voltage of the probe needle 10 is collected by the voltage sampling circuit 20, and a voltage signal corresponding to the detection voltage is outputted. The voltage comparison circuit 30 compares the voltage value of the voltage signal with the preset voltage threshold. When the voltage value of the voltage signal exceeds the preset voltage threshold, an enable signal is outputted, and the switch circuit 40 cuts off the connection between the probe needle 10 and the input interface SMA of the oscilloscope upon receiving the enable signal. In this way, when the oscilloscope probe 100 of the embodiment of the present application is used to measure the signal, if the voltage value of the measured signal is greater than the preset voltage threshold, the voltage comparison circuit 30 can output an enable signal to enable the switch circuit 40 to cut off the connection between the probe needle 10 and the input interface SMA of the oscilloscope, thereby preventing the probe needle 10 from inputting an excessively large signal and causing damage to the oscilloscope probe 100.
[0065] See also Figure 2 In some embodiments, the oscilloscope probe 100 may further include a display circuit 50. The display circuit 50 is connected to the voltage sampling circuit 20 or the voltage comparison circuit 30, and is used to receive a voltage signal and display the voltage value of the voltage signal. Thus, the tester can view the voltage of the test point of the circuit / device under test detected by the oscilloscope probe 100 through the display circuit 50, and can also record the displayed voltage value when necessary.
[0066] See also Figure 3 In some embodiments, the oscilloscope probe 100 may further include a warning circuit 60. The warning circuit 60 is connected to the voltage comparison circuit 30. When the voltage value of the voltage signal exceeds the preset voltage threshold, the voltage comparison circuit 30 sends a warning signal to the warning circuit 60, and the warning circuit 60 is used to indicate that the voltage value of the voltage signal exceeds the preset voltage threshold according to the warning signal. In this way, when the voltage at the test point of the circuit / device under test is too large, the tester can be informed according to the indication of the warning circuit 60 and promptly move the probe needle 10 of the oscilloscope probe 100 away from the test point.
[0067] The warning circuit 60 may include, for example, a warning light D1 , a buzzer, etc. When a warning signal is received, the warning light D1 lights up or the buzzer sounds an alarm, thereby alerting the tester.
[0068] See also Figure 4In some embodiments, the oscilloscope probe 100 may further include an electrostatic suppression circuit 70, which is connected to the probe needle 10 and is used to suppress the surge static electricity generated by the probe needle 10. In this way, when abnormal surge static electricity appears at the test point of the circuit / device under test, the electrostatic suppression circuit 70 can suppress the surge static electricity detected by the probe needle 10 to prevent the surge static electricity from being input into the internal circuit of the oscilloscope probe 100 and the input interface SMA of the oscilloscope, thereby preventing damage to the oscilloscope probe 100 and the oscilloscope.
[0069] See also Figure 5 , Figure 5 A schematic diagram of the circuit structure of an oscilloscope probe 100 according to an embodiment of the present application is shown.
[0070] like Figure 5 As shown, the voltage sampling circuit 20 may include a voltage dividing module 21, an amplifying module 22 and an analog-to-digital conversion module 23. The voltage dividing module 21 is connected to the probe needle 10, and the voltage dividing module 21 is used to divide the detection voltage of the probe needle 10 and output a voltage dividing signal. The amplifying module 22 is connected to the voltage dividing module 21, and the amplifying module 22 is used to receive the voltage dividing signal and amplify the voltage dividing signal. The analog-to-digital conversion module 23 is connected to the amplifying module 22, and the analog-to-digital conversion module 23 is used to receive the amplified voltage dividing signal and perform analog-to-digital conversion on the voltage dividing signal to obtain a voltage signal, which is a digital signal.
[0071] Further, the voltage divider module 21 may include a first voltage divider resistor R1, a second voltage divider resistor R2 and a third voltage divider resistor R3. The first end of the first voltage divider resistor R1 is connected to the probe needle 10, the second end of the first voltage divider resistor R1 is connected to the first end of the second voltage divider resistor R2, the second end of the second voltage divider resistor R2 is connected to the first end of the third voltage divider resistor R3, and the second end of the third voltage divider resistor R3 is grounded.
[0072] The amplification module 22 may include a comparison operational amplifier U1. A first input terminal of the comparison operational amplifier U1 is connected to a first terminal of a second voltage-dividing resistor R2, and a second input terminal of the comparison operational amplifier U1 is connected to a second terminal of the second voltage-dividing resistor R2. The comparison operational amplifier U1 is used to receive a voltage across the second voltage-dividing resistor R2 and amplify the voltage to obtain a voltage-dividing signal and then output it.
[0073] The detection voltage is divided by the first voltage-dividing resistor R1, the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3, and the voltage across the second voltage-dividing resistor R2 is obtained by the first input terminal and the second input terminal of the comparison operational amplifier U1. The comparison operational amplifier U1 amplifies the obtained voltage to obtain a voltage-dividing signal. The amplification factor of the comparison operational amplifier U1 can be set according to the resistance values of the first voltage-dividing resistor R1, the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3. For example, the amplification factor can be set to (R1+R2+R3) / R2, or a multiple of (R1+R2+R3) / R2 (less than 1), so that the voltage value of the voltage-dividing signal obtained by the comparison operational amplifier U1 is the detection voltage or a multiple value of the detection voltage. Of course, the amplification factor can be set according to the actual application requirements, and is not limited to this.
[0074] In some embodiments, the second voltage-dividing resistor R2 can be set as a high-precision thin-film resistor with a small resistance value (for example, the resistance value can be 5mΩ), and the voltage across the second voltage-dividing resistor R2 obtained by the comparison operational amplifier U1 will be very small (mV level), and then the voltage signal is obtained by gain amplification through the comparison operational amplifier U1. When there is an abnormally high voltage at the test point of the circuit / device under test, it can prevent the high voltage from being directly input into the comparison operational amplifier U1 and damaging the comparison operational amplifier U1.
[0075] The analog-to-digital conversion module 23 may include an analog-to-digital converter U2. The input end of the analog-to-digital converter U2 is connected to the output end of the comparison operational amplifier U1, and the output end of the analog-to-digital converter U2 is connected to the voltage comparison circuit 30. The analog-to-digital converter U2 is used to perform analog-to-digital conversion on the amplified divided voltage signal to obtain a voltage signal.
[0076] The amplified voltage-divided signal is converted into a voltage signal by the analog-to-digital converter U2, so as to isolate the voltage sampling circuit 20 and the voltage comparison circuit 30, thereby preventing the voltage comparison circuit 30 from being damaged when the detection voltage is too large.
[0077] Please continue reading Figure 5 In some embodiments, the voltage comparison circuit 30 may include a comparison module 31 and a storage module 32. The comparison module 31 is connected to the output end of the analog-to-digital conversion module 23, the storage module 32, and the switch circuit 40. The comparison module 31 is used to receive the voltage signal and the preset voltage threshold stored in the storage module 32, compare the voltage value of the voltage signal with the preset voltage threshold, and output an enable signal when the voltage value of the voltage signal exceeds the preset voltage threshold.
[0078] The comparison module 31 may be a device capable of identifying digital signals, so that the voltage signal output by the analog-to-digital conversion module 23 can be identified.
[0079] Furthermore, the comparison module 31 may include a decoder U3, and the storage module 32 may include a register U4.
[0080] Specifically, the input end of the decoder U3 is used to connect to the output end of the analog-to-digital converter U2 to receive the voltage signal. The decoder U3 is connected to the register U4 to read the preset voltage threshold from the register U4. The decoder U3 decodes the voltage signal to obtain the voltage value of the voltage signal, and compares the voltage value of the voltage signal with the preset voltage threshold, and outputs an enable signal to the switch circuit 40 when the voltage value of the voltage signal exceeds the preset voltage threshold. Among them, when the voltage value of the voltage signal is the detection voltage or a multiple of the detection voltage, the preset voltage threshold can be set to the maximum voltage value allowed to be input by the oscilloscope or a multiple of the maximum voltage value.
[0081] It can be understood that the decoder U3 can output a high or low level signal to the enable output terminal ENEN according to the comparison result to control the switch circuit 40 to cut off or conduct the connection between the probe needle 10 and the input interface SMA of the oscilloscope. For example, when the voltage value of the voltage signal exceeds the preset voltage threshold, the enable output terminal EN of the decoder U3 outputs a low level signal (enable signal), and the switch circuit 40 cuts off the connection between the probe needle 10 and the input interface SMA of the oscilloscope. When the voltage value of the voltage signal is lower than the preset voltage threshold or the voltage signal is not received, the enable output terminal EN of the decoder U3 outputs a high level signal, and the switch circuit 40 conducts the connection between the probe needle 10 and the input interface SMA of the oscilloscope. In this way, under normal conditions, the switch circuit 40 conducts the connection between the probe needle 10 and the input interface SMA of the oscilloscope.
[0082] Please continue reading Figure 5 The switch circuit 40 may include an isolating switch K1, a first end of the isolating switch K1 is connected to the probe needle 10, a second end of the isolating switch K1 is connected to the input interface SMA of the oscilloscope, and a controlled end of the isolating switch K1 is connected to the enable output end EN of the decoder U3. When the decoder U3 outputs an enable signal to the controlled end of the isolating switch K1, the isolating switch K1 is disconnected, thereby cutting off the probe needle 10 and the input interface SMA of the oscilloscope. The isolating switch K1 may be any controllable switch, such as a relay, a contactor, a power switch tube, a triode, and the like.
[0083] It can be understood that the controlled end of the isolation switch K1 can be turned on or off according to the high or low level of the received signal. For example, when the enable output end EN of the decoder U3 outputs a high level signal to the controlled end of the isolation switch K1, the isolation switch K1 is turned on to connect the probe needle 10 and the input interface SMA of the oscilloscope. When the enable end of the decoder U3 outputs a low level signal (enable signal) to the controlled end of the isolation switch K1, the isolation switch K1 is turned off to cut off the connection between the probe needle 10 and the input interface SMA of the oscilloscope, thereby physically isolating the probe needle 10 from the input interface SMA of the oscilloscope to prevent the probe needle 10 from transmitting an abnormally high voltage to the oscilloscope and damaging the oscilloscope.
[0084] In some embodiments, Figure 5 As shown, the display circuit 50 may include a display screen 51, which is connected to the output end of the decoder U3 to receive the voltage signal and display the voltage value of the voltage signal.
[0085] Specifically, the display screen 51 may include a digital display tube 52 , which is connected to the output end of the decoder U3 to receive a voltage signal and displays a voltage value of the voltage signal according to the voltage signal.
[0086] In some embodiments, the display circuit 50 may also only include a digital display tube 52, which is connected to the output end of the decoder U3 to display the voltage value of the voltage signal according to the received voltage signal.
[0087] In some other embodiments, the display screen 51 or the digital display tube 52 can be connected to the output end of the analog-to-digital converter U2, and the display screen 51 or the digital display tube 52 receives the voltage signal output by the analog-to-digital converter U2, and displays the voltage value of the voltage signal according to the voltage signal.
[0088] In some embodiments, Figure 5 As shown, the warning circuit 60 may include a warning switch G0 and a warning light D1, the controlled end of the warning switch G0 is connected to the decoder U3, the first end of the warning switch G0 is connected to the power supply VCC, the second end of the warning switch G0 is connected to the first end of the warning light D1, and the second end of the warning light D1 is grounded.
[0089] When the voltage value of the voltage signal exceeds the preset voltage value, the decoder U3 sends a warning signal to the controlled end of the warning switch G0, and the warning switch G0 is turned on according to the warning signal, and then the power supply VCC supplies power to the warning light D1, and the warning light D1 lights up. Therefore, the user of the oscilloscope probe 100 can determine that the test point has an abnormally high level according to whether the warning light D1 lights up, and remove the oscilloscope probe 100 in time to prevent damage.
[0090] It is understandable that the power supply VCC connected to the first end of the warning switch G0 may be the power supply inside the display screen 51. The warning switch G0 may be any controllable switch, such as a relay, a contactor, a power switch tube, a triode, etc. The warning light D1 may be a light emitting diode.
[0091] Please continue reading Figure 5 In some embodiments, the electrostatic suppression circuit 70 includes a suppression diode D2, a filter capacitor C1 and a filter resistor R4, the first end of the suppression diode D2 is connected to the probe needle 10, the second end of the suppression diode D2 is connected to the first end of the filter capacitor C1 and the first end of the filter resistor R4, and the second end of the filter capacitor C1 and the second end of the filter resistor R4 are grounded.
[0092] When an abnormal surge voltage is generated at the test point of the circuit / device under test, the surge voltage will be input to the probe needle 10. At this time, the detection voltage input by the probe needle 10 exceeds the breakdown voltage of the suppression diode D2 (for example, 50V), and the suppression diode D2 is instantly turned on. The suppression diode D2, the filter capacitor C1, and the filter resistor R4 together form a surge electrostatic suppressor, which conducts the surge voltage to ground. The filter capacitor C1 and the filter resistor R4 can quickly absorb the clutter of the surge voltage to prevent damage to the oscilloscope probe 100 and the oscilloscope. When the detection voltage input by the probe needle 10 is lower than the breakdown voltage of the suppression diode D2, the suppression diode D2 is in an open circuit state, which has no effect on the detection voltage input by the probe needle 10, so that the oscilloscope probe 100 can be used normally. Among them, the suppression diode D2 can be a voltage regulator diode or a TVS diode (Transient Voltage Suppressor). The TVS diode can be a unidirectional TVS diode (similar to a voltage regulator diode) or a bidirectional TVS diode (equivalent to two voltage regulator diodes connected in series in reverse).
[0093] It is understandable that the suppression diode D2 with a specific breakdown voltage may be set according to the test requirements of the oscilloscope probe 100 .
[0094] Please refer again Figure 5 In some embodiments, the oscilloscope probe 100 may further include a reset switch K2, a first end of the reset switch K2 is connected to a reset end of the decoder U3, and a second end of the reset switch K2 is grounded.
[0095] When the reset switch K2 is pressed, the reset switch K2 connects the reset terminal of the decoder U3 and the ground, so that the reset terminal of the decoder U3 receives a low-level signal, and the enable output terminal EN of the decoder U3 outputs a conduction signal to the switch circuit 40. The switch circuit 40 is also used to conduct the connection between the probe needle 10 and the input interface SMA when receiving the conduction signal.
[0096] For example, when the warning light D1 lights up to alarm, the tester can remove the oscilloscope probe 100 from the test point of the circuit / device under test, manually press the reset switch K2 to turn on the isolation switch K1 of the oscilloscope probe 100, and then restore the oscilloscope probe 100 to the test state. After reconnecting the probe needle 10 of the oscilloscope probe 100 to the test point of the circuit / device under test, the voltage detection of the test point can be started normally.
[0097] The tester can also manually press the reset switch K2 before using the oscilloscope probe 100 each time to ensure that the isolation switch K1 is turned on, that is, to ensure that the oscilloscope probe 100 is in a test state.
[0098] It is understandable that, in some embodiments, the oscilloscope probe 100 may further include a sampling and amplifying circuit 80, which is connected between the switching circuit 40 and the input interface SMA of the oscilloscope to amplify the signal collected by the probe needle 10 and provide it to the oscilloscope.
[0099] The above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application is described in detail with reference to the above preferred embodiments, those skilled in the art should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application. Those skilled in the art can also make other changes within the spirit of the present application and use them in the design of the present application, as long as they do not deviate from the technical effects of the present application. These changes made in accordance with the spirit of the present application should be included in the scope of protection claimed in the present application.
Claims
1. An oscilloscope probe, comprising a probe needle, characterized in that: The oscilloscope probe further comprises: A voltage sampling circuit, wherein an input end of the voltage sampling circuit is connected to the probe needle, and the voltage sampling circuit is used to collect a detection voltage of the probe needle and output a corresponding voltage signal according to the detection voltage; a voltage comparison circuit, the voltage comparison circuit being connected to the output end of the voltage sampling circuit, the voltage comparison circuit being used to receive the voltage signal and compare the voltage value of the voltage signal with a preset voltage threshold, and outputting an enable signal when the voltage value of the voltage signal exceeds the preset voltage threshold; and A switch circuit is connected between the probe needle and the input interface of the oscilloscope and is connected to the output end of the voltage comparison circuit. The switch circuit is used to cut off the connection between the probe needle and the input interface when receiving the enable signal.
2. The oscilloscope probe according to claim 1, characterized in that: It also includes a display circuit, which is connected to the voltage sampling circuit or the voltage comparison circuit, and is used to receive the voltage signal and display the voltage value of the voltage signal.
3. The oscilloscope probe according to claim 1, characterized in that: It also includes a warning circuit, which is connected to the voltage comparison circuit. When the voltage value of the voltage signal exceeds the preset voltage threshold, the voltage comparison circuit sends a warning signal to the warning circuit. The warning circuit is used to indicate that the voltage value of the voltage signal exceeds the preset voltage threshold according to the warning signal.
4. The oscilloscope probe according to claim 1, characterized in that: It also includes an electrostatic suppression circuit, which is connected to the probe needle and is used to suppress surge static electricity generated by the probe needle.
5. The oscilloscope probe according to claim 4, characterized in that: The electrostatic suppression circuit includes a suppression diode, a filter capacitor and a filter resistor. The first end of the suppression diode is connected to the probe needle, the second end of the suppression diode is connected to the first end of the filter capacitor and the first end of the filter resistor, and the second end of the filter capacitor and the second end of the filter resistor are grounded.
6. The oscilloscope probe according to any one of claims 1 to 5, characterized in that: The voltage sampling circuit comprises: A voltage dividing module, connected to the probe needle, for dividing the detection voltage of the probe needle and outputting a voltage dividing signal; an amplification module, connected to the voltage division module, the amplification module being used to receive the voltage division signal and amplify the voltage division signal; and The analog-to-digital conversion module is connected to the amplification module, and is used to receive the amplified divided voltage signal and perform analog-to-digital conversion on the divided voltage signal to obtain the voltage signal, wherein the voltage signal is a digital signal.
7. The oscilloscope probe according to claim 6, characterized in that: The voltage dividing module comprises a first voltage dividing resistor, a second voltage dividing resistor and a third voltage dividing resistor, wherein a first end of the first voltage dividing resistor is connected to the probe needle, a second end of the first voltage dividing resistor is connected to a first end of the second voltage dividing resistor, a second end of the second voltage dividing resistor is connected to a first end of the third voltage dividing resistor, and a second end of the third voltage dividing resistor is grounded; The amplification module includes a comparison operational amplifier, a first input end of the comparison operational amplifier is connected to the first end of the second voltage-dividing resistor, a second input end of the comparison operational amplifier is connected to the second end of the second voltage-dividing resistor, and the comparison operational amplifier is used to receive the voltage across the second voltage-dividing resistor and amplify the voltage to obtain the voltage-dividing signal and then output it; The analog-to-digital conversion module includes an analog-to-digital converter, the input end of the analog-to-digital converter is connected to the output end of the comparison operational amplifier, the output end of the analog-to-digital converter is connected to the voltage comparison circuit, and the analog-to-digital converter is used to perform analog-to-digital conversion on the amplified voltage division signal to obtain the voltage signal.
8. The oscilloscope probe according to claim 6, characterized in that: The voltage comparison circuit includes a comparison module and a storage module. The comparison module is connected to the output end of the analog-to-digital conversion module, the storage module and the switching circuit. The comparison module is used to receive the voltage signal and the preset voltage threshold stored in the storage module, compare the voltage value of the voltage signal with the preset voltage threshold, and output the enable signal when the voltage value of the voltage signal exceeds the preset voltage threshold.
9. The oscilloscope probe according to claim 8, characterized in that: The comparison module includes a decoder, and the storage module includes a register.
10. The oscilloscope probe according to claim 9, characterized in that: It also includes a reset switch, a first end of the reset switch is connected to the reset end of the decoder, and a second end of the reset switch is grounded; when the reset end of the decoder receives a low-level signal, the decoder outputs a conduction signal to the switch circuit, and the switch circuit is also used to conduct the connection between the probe needle and the input interface when receiving the conduction signal.