Jiseong Kim

Coil Design and Shielding Methods for a Magnetic Resonant Wireless Power Transfer System

In this paper, we introduce the basic principles of wireless power transfer using magnetic field resonance and describe techniques for the design of a resonant magnetic coil, the formation of a magnetic field distribution, and electromagnetic field (EMF) noise suppression methods. The experimental results of wireless power transfer systems in consumer electronics applications are discussed in terms of issues related to their efficiency and EMF noise. Furthermore, we present a passive shielding method and a magnetic field cancellation method using a reactive resonant current loop and the utilization of these methods in an online electric vehicle (OLEV) system, in which an OLEV green transportation bus system absorbs wireless power from power cables underneath the road surface with only a minimal battery capacity.

Measurement and Analysis of a High-Speed TSV Channel

Using high-speed through-silicon via (TSV) channels is a potential means of utilizing 3-D interconnections to realize considerable high-bandwidth throughput in vertically stacked and laterally distributed integrated circuits. However, although the TSV and a silicon interposer in a high-speed TSV channel lead to a significant decrease of the interconnect length, the received digital signal after transmission through a TSV channel is still degraded at a high data-rate due to the nonidealities of the channel. Therefore, an analysis of the signal integrity in a high-speed TSV channel is necessary. In this paper, a single-ended high-speed TSV channel is measured and analyzed in the frequency-domain and the time-domain. To measure the high-speed TSV channel, two types of test vehicles are fabricated, consisting of TSVs and interposers. With these test vehicles, the channel losses are measured in the frequency-domain up to 20 GHz, and eye-diagrams are measured in the time-domain at 1 Gb/s and 10 Gb/s. Based on these measurements, the channel loss, characteristic impedance, and reflection of the high-speed TSV channel are analyzed and compared to those of the channel in multichip module (MCM) package. Because of the losses from the silicon-substrate and the thin oxide-layer used in the TSVs, the overall loss of the high-speed TSV channel is higher than that of the MCM channel. In addition, the characteristic impedance of the high-speed TSV channel is frequency-dependent, whereas that of the MCM channel is frequency-independent. Moreover, in contrast to the MCM channel, the reflection is negligible in the high-speed TSV channel because the channel is too short and the losses are too high to be affected by the reflection. Finally, the design guidance of a high-speed TSV channel for wide bandwidth is determined based on the analysis of the measurements.

Shielded coil structure suppressing leakage magnetic field from 100W-class wireless power transfer system with higher efficiency

In this paper, the shielded coil structure using the ferrites and the metallic shielding is proposed. It is compared with the unshielded coil structure (i.e. a pair of circular loop coils only) to demonstrate the differences in the magnetic field distributions and system performance. The simulation results using the 3D Finite Element Analysis (FEA) tool show that it can considerably suppress the leakage magnetic field from 100W-class wireless power transfer (WPT) system with the enhanced system performance.

Reduction of Electromagnetic Field from Wireless Power Transfer Using a Series-Parallel Resonance Circuit Topology

In this paper, we implemented and analyzed a wireless power transfer (WPT) system with a CSPR topology. CSPR refers to constant current source, series resonance circuit topology of a transmitting coil, parallel resonance circuit topology of a receiving coil, and pure resistive loading. The transmitting coil is coupled by a magnetic field to the receiving coil without wire. Although the electromotive force (emf) is small (about 4.5V), the voltage on load resistor is 148V, because a parallel resonance scheme was adopted for the receiving coil. The implemented WPT system is designed to be able to transfer up to 1 ㎾ power and can operate a LED TV. Before the implementation, the EMF reduction mechanism based on the use of ferrite and a metal shield box was confirmed by an EM simulation and we found that the EMF can be suppressed dramatically by using this shield. The operating frequency of the implemented WPT system is 30.7㎑ and the air gap between two coils is 150㎜. The power transferred to the load resistor is 147W and the real power transfer efficiency is 66.4 %.

Mixed-Mode ABCD Parameters: Theory and Application to Signal Integrity Analysis of PCB-Level Differential Interconnects

The mixed-mode ABCD parameters are newly introduced and developed, where the definition and the connection are carefully established to have both the advantages of the mixed-mode S-parameters and the ABCD parameters, simultaneously. In addition, closed-form equations to model symmetric and asymmetric coupled transmission lines are derived. With the derived equations, the voltage transfer functions and the eye diagram of a variety of printed circuit board (PCB)-level differential interconnects are analytically attainable, which greatly enhances their applicability for signal integrity analysis. To verify the derived equations and to validate the proposed mixed-mode ABCD parameters, a series of microstrip-type differential lines on PCB test vehicles were fabricated and tested. The effectiveness of the proposed mixed-mode ABCD parameters was successfully confirmed through the comparison studies, in particular for the case of mode-conversion occurrence at the differential lines.

Modeling and Design Optimization of a Wideband Passive Equalizer on PCB Based on Near-End Crosstalk and Reflections for High-Speed Serial Data Transmission

We propose a closed-form analytic model for the newly presented passive equalizer using near-end crosstalk and reflections on printed circuit board (PCB). The proposed model is developed by using impulse response analysis and the Fourier transform. Based on the model, we propose a design-optimization procedure for the passive equalizer, which achieves eye-opening maximization and ISI minimization in order to maximize the equalization performance and reduce the design cycle. In the proposed optimization procedure, the eye-opening is maximized with a parameter sweep and peak distortion analysis, and the ISI is minimized by the proposed negative ISI cancellation technique. The proposed model and the design-optimization procedure are demonstrated experimentally for a data rate of 16 Gb/s on a 40-cm-long backplane PCB, and they achieve wideband equalization with a significant improvement in the voltage and timing margins of the received serial data.

Impact of PCB design on switching noise and EMI of synchronous DC-DC buck converter

Synchronous DC-DC buck converters operate under a few MHz but generate broadband noise up to GHz range due to its switching operation. The noise causes EMI problem through radiation and switching noise at the converter output from direct conduction. To control EMI and switching noise at the converter output, proper PCB design plays a critical role. This paper evaluates three types of GND plane layout and three types of high-voltage AC node layout for synchronous DC-DC buck converter test benches with 4-layer stack-up PCB. Transverse electromagnetic (TEM) cell measurement and time-domain measurement of switching noise at the converters output were performed for the evaluation. The source of EMI, switching noise and magnitude difference over layouts were analyzed by the impedance measurement on the test benches.

Analysis of EMF noise from the receiving coil topologies for wireless power transfer

Electromagnetic-field (EMF) noise from the only coil system with CSSR (Current source, Series resonance for TX, Series resonance for RX, and Resistive load) and CSPR (Current source, Series resonance for TX, Parallel resonance for RX, and Resistive load) topologies are featured in this paper. Wireless power transfer (WPT) system for a monitor is designed and analysed by using the equivalent circuit model. Most of the characteristic of CSSR and CSPR topologies seem similar to each other except for the current through receiving coil. EMF noise from CSSR topology is very similar to that of CSPR topology under the condition of maximum power transmission. However, when transferred power is decreased, EMF noise is decreased at only CSSR topology. Therefore, EMF noise point of view, CSSR topology is advantageous than CSPR topology.

Vertical Noise Coupling From On-Chip Switching-Mode Power Supply in a Mixed-Signal Stacked 3-D-IC

In this paper, we propose a fast and accurate model of the vertical noise coupling from an on-chip switching-mode power supply (SMPS) to a low noise amplifier (LNA) in a stacked 3-D-IC. To achieve both speed and accuracy, the model is based on the analytic formulas of static R, L, and C parasitic extraction, and includes consideration of the phase difference in the on-chip inductors using a new iterative calculation method. The proposed model and the prediction of vertically coupled noise at the LNA output using the model are experimentally validated on a fabricated stacked 3-D-IC consisting of an onchip SMPS and LNA. Good agreement with the measurements is confirmed in both the frequency domain and the time domain. The enhancements of the proposed model, including the broad model bandwidth (<; 4 GHz) as good as 3-D EM solver and 99% reduction of the simulation elapsed time (2 s) from 3-D EM solver, are confirmed. This paper also analyzes: 1) the impact of vertical noise coupling on the RF signal gain performance of the LNA and 2) the impact of variation in the stacking configuration, location, and thickness of the stacked LNA on the vertical noise coupling using the proposed model. Based on the results of our analysis, this paper proposes and verifies an effective method to reduce the vertical noise coupling using the proposed model.

Vertical Inductive Bridge EBG (VIB-EBG) Structure With Size Reduction and Stopband Enhancement for Wideband SSN Suppression

In this letter, we propose a vertical inductive bridge electromagnetic bandgap (VIB-EBG) structure for size reduction of a unit cell and the wideband suppression of simultaneous switching noise (SSN) in a multi-layer package. With the proposed vertical inductive bridge, the inductance of an EBG unit cell is effectivel increased within a compact unit cell size. Compared to the previous planar bridge EBG structure, the proposed VIB-EBG structure achieves an 86% enhancement of the fractional stopband bandwidth and a 58% reduction in unit cell size. The starting frequency of the first bandgap (fL) is significantly reduced from 4.0 to 1.7 GHz. Wideband SSN suppression with a size reduction was successfully verified by HFSS simulations and measurements.