Faculty Profiles - TOYOTA Yoshitaka

MISC - TOYOTA Yoshitaka

Division display 161 - 180 of about 309 ／ All the affair displays >>

Insertion of Dumping Resistor to Reduce RF IC-Power-Current Peak Caused by Resonance due to Parasitic Impedance

YANO Yusuke, IOKIBE Kengo, TOYOTA Yoshitaka

2011 ( 19 ) 29 - 34 2011.10

Verification of Common-Mode-Current Prediction Method Based on Imbalance Difference Model for Differential Signaling System

21st 217 - 220 2011.9

Measurement of Self-Inductance of IC Package with THRU Pattern Embedded Instead of Chip

TANIMICHI Ayumi, IOKIBE Kengo, TOYOTA Yoshitaka

IEICE technical report 111 ( 131 ) 31 - 36 2011.7

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

In IC package modeling of electrical properties, to compare model parameters extracted from results of electromagnetic calculations to those obtained from measurements is an important method for validation of the model. Only direct probing methods for special package, however, had been reported in literature. There is no method for actual packages molded with resin and mounted on printed circuit board. This paper proposes an extraction method of self-inductance of actual IC packages. Four test packages consisted of interposer and bonding wires were employed for validation of the method. Self-inductances of the four packages were extracted from measured impedance parameters obtained by a two ports measurement at board level. The test package contained a THRU line instead of IC-chip. By subtracting inductance of the THRU line from inductance between the two ports of measurement, the package inductance was obtained. As a result, the self-inductance were obtained with absolute errors between -0.8 and -0.2 nH in measurement, between -0.9 〜 -0.6 nH in electromagnetic calculations.

CiNii Article

CiNii Books

researchmap

Control and design of stopband by applying two stubs to open-stub EBG structure

NAGAO Atsushi, TOYOTA Yoshitaka, IOKIBE Kengo

IEICE technical report 111 ( 131 ) 91 - 96 2011.7

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

To suppress the parallel resonance between power/ground planes on printed circuit boards, electromagnetic bandgap (EBG) structure can be applied. The open-stub EBG structure with two stubs in a unit cell is expected to miniaturize the cell size, expand the stopband and form multi-stopbands. In addition to, compare it with mushroom-type EBG structure and open-stub EBG structure with one stub through equivalent-circuit analysis, we established the design methodology to realize both stopbands of 2.4 GHz and 5.2 GHz. As a result, different lengths with two stubs led separate stopbands of 2.4 GHz and 5.2 GHz. Furthermore, we evaluated the difference of spiral stub length between the equivalent circuit model using characteristic parameters and electromagnetic simulation that requires the physical sizes.

CiNii Article

CiNii Books

researchmap

Mode-equivalent Modeling and Identification of System with Cable Interconnection between Transmitter and Receiver Pairs (Part 2)

SEJIMA Kota, TOYOTA Yoshitaka, IOKIBE Kengo, KOGA Liuji R., WATANABE Tetsushi

IEICE technical report 111 ( 66 ) 93 - 98 2011.5

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

At the interface where two transmission lines with different current division factors are connected, there occurs mode conversion. Focusing on a transmission system where a microstrip line on printed circuit board with a transmitter or a receiver is connected to a two-wire line above the system ground, the modal equivalent-circuit model with mode-conversion sources was developed. The model was validated by comparing common mode current and normal-mode voltage between measurement and circuit simulation. As a result, both spectra have a good agreement, which indicates that mode conversion is expressed using the proposed mode-conversion sources. According to the model, two approaches were carried out to reduce normal-mode voltage in common-mode resonance: reduction in the difference of current division factors and reduction in common-mode current. It was found that both approaches can suppress mode conversion as expected by the model.

CiNii Article

CiNii Books

researchmap

Evaluation of Power/Ground Layers with EBG structure and Ferrite Film for Noise Suppression and Power-Integrity Improvement

MAHMOOD Farhan Zaheed, TOYOTA Yoshitaka, IOKIBE Kengo, KONDO Koichi, YOSHIDA Shigeyoshi

IEICE technical report 111 ( 66 ) 75 - 80 2011.5

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

Power/ground layers of Printed Circuit Board (PCB) require two conditions of noise suppression and power integrity (PI). We proposed the application of Electromagnetic Bandgap (EBG) structure and ferrite film to power/ground layers. In this paper, not only a test board with the proposed structure but three other test boards to be compared were fabricated to measure with a vector network analyzer. The measured data was evaluated for EMI and PI characteristics. Additional evaluation using a commercial circuit simulator was carried out to evaluate PI characteristics for assuming a real power-supply circuit. Through the evaluation, the proposed structure provided sufficient results. Also almost same characteristics was provided by the test board with only ferrite film.

CiNii Article

CiNii Books

researchmap

Decoupling of Power Distribution Network to Improve Tolerance of Side-Channel Attacks in Cryptographic FPGA

AMANO Tetsuo, IOKIBE Kengo, TOYOTA Yoshitaka

IEICE technical report 111 ( 18 ) 19 - 24 2011.4

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

Side-channel attack is a cryptanalytic attack by means of radio frequency (RF) power current from cryptographic IC. On-board decoupling was examined experimentally in two decoupling conditions and the default no-decoupling condition to prove its usefulness as a countermeasure against the side-channel attack. The RF power current of a cryptographic FPGA (Field-Programmable Gate Array) was decoupled with a decoupling circuit. The decoupling circuit was installed in the power distribution network of the cryptographic FPGA on a Side-channel attack standard evaluation baord, SASEBO-G. The RF power current which was generated as the FPGA was operating an AES (Advanced Encryption Standard) encryption process was detected with a current probe on power cables. The current detection was repeated until 30,000 waveforms were obtained in each decoupling conditions. The waveforms were analyzed statistically by the correlation power analysis (CPA). CPA results showed that one of the decoupling circuits improved tolerance of the FPGA to the side-channel attack, while the other decoupling circuit hardly change the tolerance. Noticeable difference between the two decoupling circuits appeared in the frequency range below the frequency of the FPGA clock. The RF power current was reduced all over the lower range in the decoupling condition the tolerance improved. The RF power current reduction was proved to be a result of the decoupling by circuit simulations.

CiNii Article

CiNii Books

researchmap

B-4-39 On-Board Decoupling to Improve Tolerance of Cryptographic Board against Side-Channel Attacks

Iokibe Kengo, Toyota Yoshitaka

Proceedings of the IEICE General Conference 2011 ( 1 ) 352 - 352 2011.2

B-4-40 Control of Stopband by Applying Two Stubs to Open-stub EBG Structure

Nagao Atsushi, Toyota Yoshitaka, Iokibe Kengo, Koga Liuji R.

Proceedings of the IEICE General Conference 353 - 353 2011

Mode-equivalent Modeling and Identification of System with Cable Interconnection between Transmitter and Receiver Pairs

TOYOTA Yoshitaka, WATANABE Tetsushi, IOKIBE Kengo, KOGA Ryuji

IEICE technical report 110 ( 300 ) 33 - 38 2010.11

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

In the transmission system where a transmitter and receiver are connected with a cable at a certain distance above the system ground, a mode equivalent-circuit model is proposed to estimate mode current flowing along the system. The simple model is based on mode-decomposition technique and places mode-conversion voltage source and current source at the interface between the transmitter/receiver and the cable where the current division factors are different. In this study, a simple cable interconnection system without dielectric was used to estimate the common-mode current flowing along the system. The circuit simulation using the proposed model showed a good agreement with the circuit simulation regarding as coupled transmission lines. In addition, the mode-current spectrum is found to be close to that obtained from full-wave analysis. Some discrepancy was observed as the distance from the system ground gets larger.

CiNii Article

CiNii Books

researchmap

EMC設計のための高速電磁界シミュレータの開発

豊田啓孝

山陽放送学術文化財団リポ-ト ( 54 ) 22 - 26 2010.10

BI-2-3 Validation of Parasitic Couplings and Combination with IBIS for PI/SI Calculation in LECCS Model

Iokibe Kengo, Toyota Yoshitaka, Koga Ryuji, Oka Norimasa

Proceedings of the Society Conference of IEICE 2010 ( 1 ) "SS - 81"-"SS-82" 2010.8

Effective Position of Decoupling Inductor Taking Parasitic Capacitances on Power Distribution Network Traces into Account

YANO Yusuke, IOKIBE Kengo, TOYOTA Yoshitaka, KOGA Ryuji

IEICE technical report 110 ( 125 ) 39 - 44 2010.7

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

High-frequency current caused by simultaneous switching of digital gates can be increased with decoupling capacitors, because equivalent series inductance (ESL) of the decoupling capacitors makes resonance with parasitic capacitance on power distribution network trace. In this report, we discussed the location of decoupling inductors as a countermeasure and to reduce the high frequency power current by a circuit simulation. We employed a four-layered printed circuit board as a device under test. The board included an oscillation circuit with a versatile inverter IC and a power distribution network. The board was modeled with a linear equivalent circuit and a current source (LECCS) for the circuit simulations of the RF powe current and power bounce. Results of the circuit simulations showed that reduction of the RF power current was larger with a decoupling inductor placed between the decoupling capacitor and the parasitic capacitance than out side the parasitic capacitance, though a peak current could be occur due to a resonance the parasitic capacitance contributed. The RF power current was reduced at all frequencies even when the decoupling inductor was placed outside the parasitic capacitance. In addition, in order to investigate influence on power integrity (PI) performance of the IC, potential difference between power terminals of chip was calculated. The simulation results showed that the decoupling inductors caused trivial deterioration in P1 performance of the IC.

CiNii Article

CiNii Books

researchmap

Calculation of Common-Mode Radiation from Single-Channel Differential Signaling System Using Imbalance Difference Model

Tohlu Matsushima, Tetsushi Watanabe, Yoshitaka Toyota, Ryuji Koga, Osami Wada

IEICE TRANSACTIONS ON COMMUNICATIONS E93B ( 7 ) 1739 - 1745 2010.7

Language：English Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

In a differential transmission line, a large common-mode radiation is excited due to its asymmetry. In this paper, the imbalance difference model, which was proposed by the authors for estimation of common-mode radiation, is extended to apply to the differential signaling systems. The authors focus on a differential transmission line with asymmetric property, which consists of an adjacent return plane and two signal lines which are placed close to an edge of the return plane. Three orthogonal transmission modes, a normal mode, a primary common mode and a secondary common mode, are defined. Among these transmission modes, the secondary common mode is dominant in radiation, and a mechanism of the secondary common-mode generation is explained. The radiated emission which was calculated using the imbalance difference model was in good agreement with that obtained by full wave calculation.

DOI： 10.1587/transcom.E93.B.1739

Web of Science

researchmap

Suppression of Guard-Trace Resonance by Matched Termination for Reducing Common-Mode Radiation

Tetsushi Watanabe, Tohlu Matsushima, Yoshitaka Toyota, Osami Wada, Ryuji Koga

IEICE TRANSACTIONS ON COMMUNICATIONS E93B ( 7 ) 1746 - 1753 2010.7

Language：English Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

We propose a novel technique of matching at both ends of the guard trace to suppress resonance. This approach is derived from the viewpoint that the guard trace acts as a transmission line. We examined that matched termination suppresses guard-trace resonance through simulating a circuit and measuring radiation. We found from these results that the proposed method enables guard-trace voltages to remain low and hence avoids increases in radiation. In addition, we demonstrated that "matched termination at the far end of the guard trace" could suppress guard-trace resonance sufficiently at all frequencies. We eventually found that at least two vias at both ends of the guard trace and only one matching resistor at the far end could suppress guard-trace resonance. With respect to fewer vias, the method we propose has the advantage of reducing restrictions in the printed circuit board layout at the design stage.

DOI： 10.1587/transcom.E93.B.1746

Web of Science

researchmap

Linear Equivalent Circuit Model of Inverter in Microwave Oven for EMI Filter Design

IOKIBE Kengo, WATANABE Tetsushi, SAKIYAMA Kazuyuki, SAITO Yoshiyuki, TOYOTA Yoshitaka, KOGA Ryuji

IEICE technical report 110 ( 84 ) 25 - 30 2010.6

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

A Linear equivalent circuit model of inverter was proposed for applying to designing EMC filters to reduce the conducted emission from electrical appliances with switched-mode power supplys as inverters and converters. We employed a microwave oven as the equipment under test(EUT)and measured the conducted emission voltage at mains port with a line impedance stabilizing network(LISN). Measured disturbances contained both the differential and common modes and we determined the proposed model to have a circuitry structure composed of differential- and common-mode blocks. We, then, described a simple method to determine model parameters from measurements and decided the parameters with the method. With the proposed model, the conducted emission voltage of the EUT was estimated through circuitry simulation and compared to measurement. The comparison showed that the model predicted performance of the EMI filter in reduction of the conducted emission in practical accuracies at frequencies in which model parameters determined had been reasonable.

CiNii Article

CiNii Books

researchmap

BI-2-1 Generation Mechanism and Suppression Method of Common-mode Radiation due to Imbalance Difference between transmission lines

Watanabe Tetsushi, Matsunaga Shigeki, Matsushima Tohlu, Wada Osami, Toyota Yoshitaka, Koga Ryuji

Proceedings of the IEICE General Conference 2010 ( 1 ) SS.110-SS.111 - SS-111 2010.3

B-4-5 Accuracy Evaluation of Combined IBIS and LECCS Macro Models by SPICE Simulations for PI and SI Performances

OKA Norimasa, IOKIBE Kengo, TOYOTA Yoshitaka, KOGA Ryuji

Proceedings of the IEICE General Conference 2010 ( 1 ) 355 - 355 2010.3

平衡度不整合理論に基づく多チャンネル差動伝送線路のコモンモード放射予測

松嶋徹, 渡辺哲史, 豊田啓孝, 和田修己, 古賀隆治

エレクトロニクス実装学会講演大会, 10B-06,, pp. 28-29 2010.3

Development of a Equivalent Circuit Model with Transmission Line Model for Designing Filter Formed on Printed Circuit Boards

MATSUMOTO Keisuke, TOYOTA Yoshitaka, IOKIBE Kengo, KOGA Ryuji

IEICE technical report 109 ( 370 ) 81 - 86 2010.1

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

Slit pattern formed on return plane of printed circuit boards behaves like a passive element. A defected ground structure (DGS) is one of them. The characteristics of DGS easily varies with the slit pattern so that it is expected for various applications. Since a design method has not been developed, however, we need to establish the method to design a slit pattern. Some equivalent circuit models have been used but they consist of lumped elements and require full-wave simulation. In addition, value of the lumped elements have no relation to a physical parameters. So it is not useful for filter designing. In this report, we proposed equivalent circuit model with transmission line model for DGS with filter function. Transmission characteristic was calculated by both full-wave simulator and circuit simulator with the proposed equivalent circuit model and the first stop-band width calculated by circuit simulator was in agreement with full-wave simulator.

CiNii Article

CiNii Books

researchmap

　 PREV - NEXT 　

< TOYOTA Yoshitaka >

MISC - TOYOTA Yoshitaka