CN201477129U - A Measuring System Realizing Interface Discharge - Google Patents

Abstract

A measuring system capable of realizing interface discharge, comprising an interface (20), an interface circuit (21), and a measuring instrument (22). The interface (20) includes a signal interface end (201) and a ground interface end (202). The interface circuit (21) includes a first discharge tip (211), a second discharge tip (212), a discharge gap (213) and a solder resist window (214), and the first discharge tip (211) is connected to the signal interface terminal (201) , the second discharge tip (212) is connected to the ground interface (202), and the solder resist window (214) makes the first discharge tip (211), the second discharge tip (212) and the discharge gap (213) fully exposed in the air , adjusting the size of the discharge gap (213) according to safety standards or actual design requirements. When the interface (20) generates static electricity, the discharge tip breaks through the air and discharges to the ground, thereby suppressing static electricity discharge and protecting internal components of the instrument. The utility model has the characteristics of simple structure, small input capacitance, low price and the like.

Description

A Measuring System Realizing Interface Discharge

technical field

The utility model relates to the field of systems for measuring electric variables, in particular to the field of systems for measuring electric variables that can realize interface circuit discharge.

Background technique

In daily life, static electricity can be said to be everywhere. From the contact and separation of two different objects to the flow of dry air, it is the cause of static electricity. If the conditions are suitable, static electricity can occur instantly, and the generation of static electricity will also cause harm to electronic components. The harm caused by electrostatic discharge (ESD) to electronic components can cause a variety of problems, and serious damage can damage important parts of the product.

The interface of various measuring instruments is a place that may be subject to electrostatic discharge. When people carry static electricity to touch the instrument interface, or touch the instrument interface with an object carrying static electricity, the interface may be charged with static electricity and transmitted to the inside of the instrument. If there is no protection , the components inside the instrument are easily damaged. In order to solve the above problems, a measurement system capable of discharging the interface is provided in the prior art. The system will be briefly introduced below with reference to FIG. 1 .

Please refer to FIG. 1 , a system 1 includes an interface 10 , an interface circuit 11 , and an oscilloscope 12 . The interface 10 includes a signal interface terminal 101 and a ground interface terminal 102 . The interface circuit 11 includes a piezoresistor 111 .

The interface 10 , the interface circuit 11 and the oscilloscope 12 are sequentially connected in series. The piezoresistor 111 is connected between the signal interface terminal and the ground interface terminal. The signal interface terminal 101 sends the received signal to the oscilloscope 12 .

The varistor 111 is a resistor whose "resistance value changes with voltage within a certain current and voltage range" or "resistance value is sensitive to voltage". Its biggest feature is that when the voltage applied to it is lower than its threshold UN, the current flowing through it is extremely small, which is equivalent to a closed valve. When the voltage exceeds the threshold UN, the current flowing through it surges , which corresponds to the valve opening. The system 1 utilizes this characteristic of the piezoresistor 111 and arranges it between the signal interface terminal 101 and the ground interface terminal 102 . If the interface circuit 10 is subjected to electrostatic discharge, the resistance of the varistor 111 decreases sharply, and the electrostatic current flows to the ground through the varistor 111 , thereby protecting the safety of devices behind the interface circuit 10 .

In the system 1, the interface circuit 10 is mainly used to receive various input signals, and it may be a signal input terminal of an instrument, an input interface such as SMA, SMB or USB. The measuring instrument 12 may be various electrical measuring instruments such as an oscilloscope, a multimeter, or a signal generator.

It can be seen that the prior art mentioned above can protect the measuring equipment from electrostatic discharge. However, for some measuring equipment, due to the high-impedance input, the size of the input capacitance has a greater impact on the bandwidth, so if the piezoresistor capacitance connected between the signal interface terminal 101 and the ground interface terminal 102 is large, it will affect the interface 10. The input capacitance, so as to reduce the bandwidth, which brings difficulties to the design. If the above problems are to be solved, a varistor with a particularly small capacitance needs to be selected, but such a varistor generally has a higher price.

Utility model content

The purpose of the utility model is to overcome the shortcomings in the prior art and provide a measurement system capable of realizing discharge of the interface circuit.

A measurement system capable of realizing the discharge of an interface circuit, comprising an interface, an interface circuit, and a measuring instrument, the interface includes a signal interface end for receiving signals, and a ground interface end for grounding, the described The interface circuit is connected in series between the interface and the measuring instrument, and the signal interface port sends the received signal to the measuring instrument,

In the interface circuit, it includes a first discharge tip, a second discharge tip, a discharge gap and a solder resist window, the first discharge tip is connected to the signal interface port, and the first discharge tip is connected to the signal interface port. The two discharge tips are connected to the ground interface, the first discharge tip is not connected to the second discharge tip, and the unconnected end of the first discharge tip is connected to the second discharge tip. The unconnected ends are opposite, the discharge gap is between the unconnected end of the first discharge tip and the unconnected end of the second discharge tip, and the solder resist window covers the first above the discharge tip, the second discharge tip and the discharge gap,

The first discharge tip and the second discharge tip discharge to the ground when static electricity is generated at the interface,

The solder resist window fully exposes the first discharge tip, the second discharge tip and the discharge gap to the air.

In the measurement system described in the present invention, the first discharge tip and the second discharge tip may be formed by PCB traces.

The measurement system described in the utility model not only can realize the discharge of the interface circuit, but also has the characteristics of simple structure, small input capacitance and low price.

Description of drawings

Fig. 1 is a schematic structural diagram of a measuring system 1 in the prior art.

Fig. 2 is a schematic structural diagram of the measurement system 2 in the preferred embodiment of the utility model.

Fig. 3 is a perspective view of the straight BNC interface 3 in the preferred embodiment.

Fig. 4 is a schematic diagram of the structure of the BNC pad 4 in the preferred embodiment.

Detailed ways

The best embodiment of the present utility model is described below in conjunction with accompanying drawing.

Please refer to FIG. 2 , the measurement system 2 used in this embodiment includes an interface 20 , an interface circuit 21 , and an oscilloscope 22 . The interface 20 includes a signal interface terminal 201 and a ground interface terminal 202 . The interface circuit 21 includes a first discharge tip 211 , a second discharge tip 212 , a discharge gap 213 and a solder resist window 214 .

Wherein, the signal interface end 201 is connected to the oscilloscope 22, the ground interface end 202 is connected to the ground, the first discharge tip 211 is connected to the signal interface end 201, the second discharge tip 212 is connected to the ground interface end 202, and the discharge gap 213 is in the first discharge position. Between the tip 211 and the second discharge tip 212 , the solder resist window 214 covers the first discharge tip 211 , the second discharge tip 212 and the discharge gap 213 .

In this example,

The signal interface terminal 201 is used to receive the signal and send it to the oscilloscope 22 for signal processing. The first discharge tip 211 and the second discharge tip 212 discharge to the ground through the discharge gap 213 when static electricity occurs on the interface 20, and the welding resistance The window 214 fully exposes the first discharge tip 211 , the second discharge tip 212 and the discharge gap 213 to the air, which facilitates discharge.

In this example,

Please refer to Fig. 3, the interface 20 selects the signal input interface of the oscilloscope, that is, a straight BNC interface, the straight BNC interface 3 includes a signal connection pin 31, a ground pin 32, a ground pin 33, a ground pin 34 and a ground pin Feet 35. The signal connection pin 31 is used for receiving signals, and the ground pin 32 , the ground pin 33 , the ground pin 34 and the ground pin 35 are respectively connected to the ground.

In this example,

Referring to FIG. 4 , the BNC pad 4 includes a solder hole 41 , a solder hole 42 , a solder hole 43 , a solder hole 44 , a solder hole 45 , a first discharge tip 211 , a second discharge tip 212 and a solder resist window 214 .

The welding hole 41 and the welding hole 42 protrude from the first discharge tip 211 and the second discharge tip 212 respectively through the way of PCB routing, and the solder resist window 214 exposes the first discharge tip 211 and the second discharge tip 212 to the air, Not covered by solder mask. The solder resist layer mentioned here is used to apply solder resist materials such as solder resist green oil, so as to prevent the places that do not need to be soldered from being contaminated with solder. The solder resist window 214 refers to the exposed places on the solder resist layer that need to be soldered, and these places do not need to be coated with solder resist materials such as solder resist green oil.

In this example,

Referring to Fig. 3 and Fig. 4, the signal connection pin 31, the ground pin 32, the ground pin 33, the ground pin 34 and the ground pin 35 of the straight BNC interface 3 are respectively connected to the welding holes 41 of the BNC pad 4 , welding hole 42, welding hole 43, welding hole 44 and welding hole 45 are connected. And the welding hole 43 , the welding hole 44 and the welding hole 45 have the same effect as the welding hole 42 .

In this example,

The discharge point gap 213 is obtained according to specific design requirements or safety standards to be followed, for example, according to the discharge gap in "GB4793.1-2007 Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory Use Part 1: General Requirements" The creepage distance can be qualitatively calculated, and the specific distance can be obtained by applying high voltage to the straight BNC interface 3 and observing whether the leakage current reaches the required safe current.

When there is static electricity in the interface 20, a large amount of charges are accumulated on the first discharge tip 211 and the second discharge tip 212, and when reaching a certain level, the air between the first discharge tip 211 and the second discharge tip 212 is broken down, and the Discharge, thereby effectively suppressing electrostatic discharge.

Since the relative area of the first discharge tip 211 and the second discharge tip 212 is very small, the parasitic capacitance between them is very small, so the influence on the input capacitance of the oscilloscope is very small.

As an example, the interface 20 may be an interface of various electronic measuring instruments, such as SMA, SMB or USB interfaces.

As an example, the interface circuit 21 may be an input amplifier circuit, a communication interface circuit, or a driving circuit.

As an example, the first discharge end 211 and the second discharge end 212 may be formed by PCB traces, or may be formed by other methods, as long as the two discharge ends are made of copper skin and the two discharge ends are opposite to each other.

The above specific embodiments are only used to illustrate the present utility model, but not to limit the present utility model.

Claims (2)

1. measuring system that can realize interface discharge, comprise an interface, one interface circuit, one surveying instrument, described interface comprises that one is used for the signaling interface end of received signal, and one is used for the ground interface end of ground connection, and described interface circuit is connected in the middle of described interface and the described surveying instrument, described signaling interface end is delivered to described surveying instrument with the signal that receives

It is characterized in that, in described interface circuit, comprise one first discharge tip, one second discharge tip, one discharging gap and a welding resistance window, described first discharge tip is connected with described signaling interface end, described second discharge tip is connected with described ground interface end, described first discharge tip is not connected with described second discharge tip, the not link of described first discharge tip is relative with the not link of described second discharge tip, described discharging gap is in the not link and not between the link of described second discharge tip of described first discharge tip, described welding resistance window covers described first discharge tip, above described second discharge tip and the described discharging gap

Described first discharge tip and described second discharge tip are discharged when described interface produces static over the ground,

Described welding resistance window fully is exposed in the air described first discharge tip, described second discharge tip and described discharging gap.

2. measuring system according to claim 1 is characterized in that, described first discharge tip and second discharge tip are made of the PCB cabling.

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