JPH046483A - Evaluation of esd of communication apparatus - Google Patents

Abstract

PURPOSE:To enable evaluation of ESD (electrostatic discharge) as a single body without being affected by the way of laying of a connecting cable of a peripheral apparatus with an apparatus to be tested and other apparatuses and others, by separating a power source of the apparatus to be tested and other apparatuses and a GND line completely. CONSTITUTION:A cable 7 connecting an apparatus 4 to be tested with a peripheral apparatus 8 is so constructed as to be kept away from a base earth plane of the apparatus 4 and thereby a stray capacity which the cable 7 has with a base earth plate 2 is eliminated. Besides, an isolation transformer 9 separates a blade-type ESD tester 3 and a power line of the apparatus 4 and the apparatus 8, and a high-frequency component which can not be separated completely by the transformer 9 is cut by an in-phase winding core 10. In this way, a return route from an AC line of the apparatus 8 is cut, the frame ground of the apparatus 8 is suspended and thus a route of inflow of a noise current generated in a frame of the apparatus 4 to the apparatus 8 is cut off.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to ESD (ESD) of communication equipment used in combination with other equipment.
The present invention relates to an evaluation method (electrostatic discharge).

[Conventional technology]

An example of the conventional ESD evaluation method is shown and explained in Section 2.

In the figure, 1 is an insulating sheet, 2 is a reference ground plate, 3 is a two-blade ESD tester, 4 is a device under test, and 5 is a cable connecting this device under test 4 to another device 6.

Next, a conventional ESD evaluation method will be explained.

First, the device under test 4 is connected to the external device f6 using the cable 5 or the like to put the device under test 4 into a pseudo operating state. In this state, static electricity is applied to the device under test 4 by the ESD tester 3 to evaluate whether the device under test 4 does not malfunction, including the operation with other devices 6.

Cocoa, AC100V'l [#, GND (FG) line is common to all measurement systems.

Next, noise DC generated by static electricity applied from the ESD tester 3 to the device under test 14 normally returns through the FG line of the device under test 4, but because the noise current is of high frequency, the cable 5 It may also flow into other devices 6 through the network, causing them to malfunction.

In this case, high-frequency noise is determined by the applied static electricity and the structure of the device under test, and is generated by forming resonance loops throughout the test system. A part of this high frequency noise is caused by the FG of cable 5,! [, through signal lines, etc., and capacitively coupled to *6 in addition to being connected.

Flows into inductive coupling. These are common ACs.

Returning via the FC line may cause other devices to malfunction.

[Problem to be solved by the invention]

In the conventional BSD evaluation method as described above, the high-frequency noise WL flow propagates through the cable and causes the connected device to malfunction, so the evaluation results are affected by the difference in the peripheral devices connected, and the way the connecting cable is routed. There was a problem in that the evaluation results were clearly affected.

This invention was made to solve this problem, and provides an END evaluation method for communication equipment that can absolutely evaluate the ESD of a single device under test without being affected by the connected peripheral devices and the way the connecting cables are routed. The purpose is to obtain.

Furthermore, the present invention provides an ES for communication equipment that can also evaluate the demarcation point of responsibility between other equipment and the own equipment using this method.
The purpose is to obtain a D evaluation method.

[Means to solve the problem]

The ESD evaluation method for communication equipment according to the present invention is a method for ESD evaluation of communication equipment used in combination with other equipment, by completely separating the power supply and ω lines between the equipment under test and other equipment. This allows the ESD of a single device under test to be evaluated without being affected by the environment.

Further, an ESD evaluation method for communication equipment according to another invention of the present invention is a method for ESD evaluation of communication equipment used in combination with other equipment, in which the power supply/GND line between the equipment under test and the other equipment is completely separated, and By moving the cable connecting the other device away from the reference ground plane of the device under test, it is possible to evaluate the gsD of the device under test without being affected by the way the cable is routed.

[Effect]

In this invention, the isolation transformer and the in-phase wound core separate the AC line between the device under test and other devices, which can serve as a return path for high-frequency noise that attempts to flow into peripheral equipment, and also provide another return path. Route F
By disconnecting the G line, there is no return path.

Furthermore, high-frequency noise current flowing into the cable due to the stray capacity between the cable and the reference ground plate is prevented by keeping the cable away from the reference ground.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram for explaining an embodiment of the ESD evaluation method for communication equipment according to the present invention.

In FIG. 1, the same reference numerals as in FIG. It is configured to move away from the surface. 9 is a vane-type ESD tester 3゜device under test 4 and other peripheral devices 8
An isolation transformer 10 for isolating the power supply line from the power supply line is an in-phase winding core that cuts high frequency components that cannot be separated by the isolation transformer 9.

The present invention is configured so that the ESD of a single device under test can be evaluated without being affected by other connected devices or the measurement environment by completely separating the power and GND lines between the device under test 14 and other peripheral devices 8. has been done.

Another aspect of the present invention is to completely separate the power supply/GND lines between the device under test 4 and other peripheral devices 8, and connect the connection cable 7 with the other peripheral devices 18 to the reference ground of the device under test 4. By keeping it away from the surface, the ESD of the device under test can be evaluated without being affected by the cable routing.

Next, the FJSD evaluation method of the embodiment shown in FIG. 1 will be explained.

The static electricity discharged from the ESD tester 3 is transferred to the device under test 4.
The power supply cables also cause flea in the shield loop, resulting in high-frequency noise current. Therefore, υ high-frequency noise is introduced into the circuit in the device under test 4 or the signal line in the connection cable 7 due to galvanic coupling and capacitive corrosion resistance. At this time, if there is a return path for this noise in the peripheral device 8, a noise current will flow from the device under test 4 to the peripheral device 8, causing the peripheral device 8 to malfunction.

In order to avoid this, in the present invention, the power line of the peripheral device 8 is completely separated from the device under test 4 in terms of high frequency using the isolation transformer 9 and the in-phase winding core 10. The return path of the AC line was cut, the frame ground of other devices was floated, and the path of the noise current generated in the frame of the device under test 4 from flowing into other peripheral devices 8 was also cut off.

Furthermore, due to the stray capacity that the cable that connects the device under test 4 and other peripheral devices 8 has between it and the reference ground plate 2, high-frequency noise current flows through the connection cable 7 and returns to the reference ground plate 2. . To prevent this,
By moving the connection cable 7 away from the reference ground plate 2, the above-mentioned stray capacity is eliminated.

In the above embodiment, a method was described in which the ESD evaluation of the device under test 4 can be performed by cutting off the propagation path of high-frequency noise carried by the device under test 4 to other peripheral devices 8. If you change your way of thinking, isolation transformer 9. This means that the in-phase winding core 10 makes the peripheral fI/L8 less susceptible to electrostatic discharge of the device under test 4. In other words, in order to make a device used in combination with other devices less susceptible to KSD generated in a connected device, an isolation transformer 9 and an in-phase winding core 10 may be added to the device's AC line. .

〔Effect of the invention〕

As explained above, this invention completely separates the power lines of the device under test and peripheral devices other than the ESD tester, furthermore, floats the 7-ram ground of the peripheral devices, and The cables connecting these are configured to be kept away from the reference ground plate of the device under test, so ESD evaluation of communication equipment used in combination with other equipment will have an impact on peripheral devices and how to route the cables connecting them. This method has the advantage that it is possible to evaluate the device under test as a standalone unit without being subject to any errors, and because it is an absolute evaluation, it is possible to clearly confirm the effectiveness of ESD countermeasures.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining an embodiment of the ESD evaluation method for communication equipment according to the present invention, and FIG.
, is a block diagram for explaining an example of the SD evaluation method. 4...Equipment under test, 7...Connection cable, 8...
...Peripheral equipment, 9...Isolation transformer, 1011・Enjoy・ms volume*:rA.

Claims (2)

[Claims] (1) In the ESD evaluation method of communication equipment used in combination with other equipment, the power supply and GND lines between the equipment under test and other equipment are completely separated, so that the equipment under test is not affected by other connected equipment or the measurement environment. An ESD evaluation method for communication equipment, characterized in that the ESD of a communication device can be evaluated. (2) In an ESD evaluation method for communication equipment used in combination with other equipment, the power and GND lines between the equipment under test and the other equipment are completely separated, and the connection cable with the other equipment is connected to the equipment under test. An ESD evaluation method for communication equipment, characterized in that the ESD of a single device under test can be evaluated without being affected by the way the cable is routed by keeping it away from a reference ground plane.