Indirect Electrostatic Discharge Research Articles

Alternative test set-up for testing the immunity of spacecraft equipment against discharge of electrostatic energy (ESD)

Discharge of electrostatic energy, often referred to as electrostatic discharge (ESD), is a potential threat to all electronic equipment and in particular to equipment flown on spacecraft. Once the spacecraft is in orbit, its equipment will be exposed to indirect effects of ESD, mainly coupled through wires. As opposed to equipment on ground, satellite equipment that suffered from ESD in orbit cannot be repaired any more, thus it is of high interest to ensure that spacecraft equipment can with stand ESD in space. In order to verify that this equipment is able to operate normally when exposed to indirect ESD effects and does not suffer from malfunctions or upsets, tests are performed according to the applicable standards [1], [2] for spacecraft. In this article an alternative test method is proposed to replace the existing standard test set-up with a much simpler one, improving the repeatability of the test and avoiding the use of components difficult to procure.

An Evaluation Method of Electromagnetic Interference on Bio-Sensor Used for Wearable Robot Control

Applications of wearable bio-sensors are rapidly increasing for health care and medical purposes, but various sinusoidal and impulse electromagnetic interferences can have a significant influence on their performance. In this paper, we focus on the electromagnetic interference evaluation of bio-sensors used for control of wearable robots, such as a myoelectric artificial hand. We proposed a method for measuring the common-mode voltage between the human body with a bio-sensor and the ground plane, which is generated by external sinusoidal or impulse electromagnetic fields. First, using sinusoidal electromagnetic interference, we clarified that the mechanism of generation of interference voltage in wearable bio-sensor is due to unbalance of contact resistances between pair of bio-signal detection electrodes. Next, as an example of impulse electromagnetic interference, we evaluated the interference voltage generated in the bio-sensor by combining the proposed measurement method with electric circuit simulation under the IEC-prescribed indirect electrostatic discharge test environment. This method provides a powerful means for evaluating the interference characteristics in the wearable robot design stage.

Effect of ESD on complex programmable logic device and field programmable gate arrays

Complex electronics devices are becoming more sensitive to electrostatic discharge (ESD). These components are being developed with higher density (extra memory bits per unit volume) and are becoming faster (MHz, GHz, THz, etc.). These upgrades in technology do not come without a technological price. By enhancing the products' performance to meet the users' demands and requirements, one drawback is the reduction in the ESD sensitivity voltage levels. Indirect and direct air/contact discharge test has been conducted on the ALS-SDA-CPLD/FPGA trainer kit linked to the digital to analog converter (DAC) module. The Field Programmable Gate Arrays (FPGA) and Complex Programmable Logic Devices (CPLD) are found to be very ESD sensitive. The FPGA 3s50 IC was affected during the contact discharge to the input pin. There was damage to the bond pad as well as the metal top layer was damaged. The DAC ICs were affected during the ESD discharge one due to direct ESD effects and the other due to indirect ESD effects. There was dielectric breakdown damage observed in the CPLD 9572 IC.

Effect of Radiated Field Due to ESD on Ones and Zeroes of the Serial Data Stream

The circuit with an output of specified serial data stream has been exposed to the radiated electromagnetic fields generated by indirect discharge from the ElectroStatic Discharge (ESD) simulator. The circuit malfunctioned at a distance of 35 cm from the point of discharge. The ESD transient pulse introduced affected only the data stream and binary counter Integrated Circuit (IC) SN74LS393N was found to be malfunctioning. The counter IC passed the parameter test but failed functionally as all the output pins were malfunctioning. The circuit that failed did not have decoupling capacitors connected to the Vcc supply. Another circuit designed with decoupling capacitors connected to the Vcc supply of all the IC’s has been exposed to indirect ESD air discharge. The effect of the ESD transient pulse on the ones and zeroes of the specified data stream has been observed. The amplitude of the serial data stream has been affected but the order of transmission of the bits has not changed. If the change in amplitude is greater than the set threshold then the order of transmission of bits can change and this becomes critical for sensitive circuits where the set threshold is very small. The decoupling capacitors provided protection against any malfunction of the integrated circuits.

Investigation of Indirect Electrostatic Discharge (ESD) for a Three-Body Problem

An experimental investigation of indirect electrostatic discharge events for an inline three-body geometry was undertaken. Using conducting cylinders of different sizes to model the test system's conductors, capacitance coefficients were measured, and body potential differences and electric fields were calculated for different geometries of the three floating conductors in close vicinity. The test geometry was chosen to model the approach of the charged human body to an electronic system, which has a neighboring floating conductor; this situation may arise in a manufacturing environment where faulty grounding exists. The parameters studied include body sizes, test geometry, and the relative magnitude and polarity of the charges on the three bodies. An analysis of both first and secondary discharge events is presented and interpreted using a series of charge sensitivity factors. Conditions to support secondary discharges are investigated as a two-body problem

Transient near-field effect of electrostatic discharge

The transient near-field of the electrostatic discharge (ESD) is a kind of high power transient phenomenon, which is strongly affected by the discharge current waveform. In this paper, two different kinds of discharge current waveforms satisfying the definition of the IEC61000-4-2 are introduced. The alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method is applied to simulate the transient near-field of the indirect ESD through the vertical couple plane (VCP). The configuration of the current source is considered carefully. The simulation results under different discharge current waveforms show different transient effects. The simulated data are compared with those measured by an optic testing system

Investigation of electrostatic discharge (ESD) for a three-body problem with small gaps

An experimental investigation of indirect electrostatic discharge (ESD) events for an inline three-body geometry was undertaken. Using conducting cylinders of different sizes to model the test system's conductors, capacitance coefficients were measured; body potential differences and electric fields in air gaps were calculated for different geometries of the three floating conductors in close proximity. The test geometry was chosen to model the approach of the charged human body to an electronic system that has a neighboring floating conductor. The possibility of primary and secondary discharges was studied for various body sizes and test geometries. The results of this work provide a better understanding of the fundamental principles involved in the ESD event involving three bodies separated by small gaps. The methodology may have application in analyzing ESD events in small-gap structures including microelectromechanical systems (MEMSs).

Fields on the horizontal coupling plane excited by direct ESD and discharges to the vertical coupling plane

Field levels in indirect electrostatic discharge (ESD) test setups are hardly known yet. It has been proposed to ANSI and IEC to use a horizontal simulator position instead of a vertical position in indirect ESD testing. This paper shows the field values on the horizontal coupling plane for different excitations and grounding topologies and questions if the goal of the change – a reduction of the simulator influence – will be achieved. Also, investigations dealing with the sensitivity of digital devices to impulsive fields are presented.

A new threat-EMI effect by indirect ESD on electronic equipment

A discussion is presented of the need to recognize the occurrence of indirect electrostatic discharge (ESD) on electronic equipment. The use of a detector for this application is outlined along with detector response. Current risetime versus discharge voltage is examined as an antenna-induced voltage versus discharge voltage. Electromagnetic wave intensity inside a copper cabinet is also discussed. >