Search

This paper presents the interleaved four-phase buck-based current source in continuous conduction mode with proposed isolated energy-recovery scheme for electrical discharge machining (EDM). EDM requires a pulse current with high slew rate in the output current of the current source. The interleaving technique allows the output slew rate of the buck-based current source to be improved due to the existence of the paralleled inductors at the start of discharge. The proposed isolated energy-recovery scheme provides a major path for the inductor to release its stored energy, thus avoiding high voltage stress in the output terminal when the gap reverts to the high-impedance state. The energy stored in the inductor is recycled to the input capacitor and can be reused for machining. The experimental results validate that the output current slew rate is high and that the energy is recovered when the gap is in the high-impedance state. Index Terms--Buck-based, current source, EDM, energy-recovery, interleaving.

The effect of pressure on liquid-phase electrical discharges was investigated by using a stainless steel high-pressure reactor combined with a high-voltage pulse forming network. The initiation breakdown voltage was obtained under various pressures up to 1380 kPa (200 lb/[in.sup.2]). The discharge characteristics including current and voltage waveforms as well as power per pulse were determined. The effect of pressure on streamer chemical reactions was also investigated by measuring the formation rate of hydrogen peroxide ([H.sub.2][O.sub.2]) in the solution. Experimental results showed that the initiation voltage is linearly dependent on pressure. The initiation voltage and power were correlated to the increase of heat requirement to vaporize liquid water with increasing pressure. On the other hand, when the input voltage exceeds the initiation voltage such that a stable discharge can be formed, the discharge characteristics are not affected by pressure. Hydrogen peroxide generation was also not affected by external pressure for conditions with stable discharge. To explain the aforementioned results, the bubble theory of liquid-phase breakdown initiation is discussed. Index Terms--Discharge in water, discharge initiation, hydrogen peroxide formation, pressure.

At IEE RAS, from the middle of the 1960s, the investigations of pulsed electric arcs in hydrogen, nitrogen, argon, etc., at high initial density are carried out. From this time, many pulsed plasmatrons (PPs), electrodischarge light-gas launchers (EDL), combined systems, unique diagnostic PP operating at hydrogen at initial pressure up to 150 MPa, and experimental facilities had been developed. The highest energy in the world of 10 MJ supplied from the shock generator into the discharge chamber of PP was input. Many experimental data on processes in the EDL and PP were obtained. The bodies of 0.2 g to ~9 km/s, 12 g to ~6 km/s, and 300 g to ~2 km/s were launched. Index Terms--Electric arc, high current, hydrogen, launching, pulsed discharge.

Cable discharge events (CDEs) have been found to be the major root cause of inducing hardware damage on Ethernet ICs of communication interfaces in real applications. Still, there is no device-level evaluation method to investigate the robustness of complementary metal--oxide--semiconductor (CMOS) devices against a CDE for a layout optimization in silicon chips. The transmission-line pulsing (TLP) system was the most important method used to observe the electrical characteristics of semiconductor devices under human-body model (HBM) electrostatic discharge (ESD) stress. To understand the physical characteristics and CDE robustness of on-chip protection devices, the long-pulse transmission-line pulsing (LP-TLP) system is proposed in this paper and used to simulate the influence of CDE on Ethernet-integrated circuits. The secondary breakdown characteristics of the CDE protection devices under different layout styles and parameters can be measured and analyzed by the proposed LP-TLP with pulsewidths of 500 or 1000 ns. Furthermore, measured results using the LP-TLP system are compared with results measured by the traditional 100-ns TLP system. The experimental results with silicon devices in 0.18-[micro]m CMOS process have shown that the CDE robustness of n-channel metal--oxide--semiconductor (NMOS) and p-channel metal--oxide--semiconductor (PMOS) devices in deep-submicrometer CMOS technology is much lower than their HBM ESD robustness. By using the proposed LP-TLP system, one set of design rules for I/O devices to sustain high CDE robustness in a given CMOS process can be evaluated and built up for chip layout. Index Terms--Cable discharge event (CDE), electrostatic discharge (ESD), long-pulse transmission line pulsing (LP-TLP), transmission line pulsing (TLP).

This paper investigates how dynamics of an HF oscilloscope affects standardized metrics (i.e., rise time and peak value) of a recorded electrostatic discharge (ESD) current pulse and evaluates the oscilloscope measurement uncertainty. A frequency-domain dynamic model of the oscilloscope, based on measurements of the input reflection and voltage gain magnitude, is derived. The complex voltage gain is approximated with a transfer function to take into account unmeasured phase shift. A high-order discrete-time filter is designed to fit the measured voltage gain magnitude not only in the passband, but also beyond it as well. Since the measured data are burdened with measurement uncertainties, the worst-case deviations of the oscilloscope input impedance and the voltage gain (in the form of envelopes of the frequency responses) are calculated, and components of Type B uncertainty of the ESD pulse metrics corresponding to these deviations are estimated using the sensitivity method. Index Terms--Frequency-domain analysis, modeling, oscilloscopes, transfer functions, uncertainty.