Faculty Profiles - TOYOTA Yoshitaka

MISC - TOYOTA Yoshitaka

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Examination of Power-Ground Resonance for IBIS Model with Non-Ideal Power Supply

Norimasa Oka, Kengo Iokibe, Yoshitaka Toyota, Ryuji Koga

Proceedings of 2009 Internatinal Symposium on Electromagnetic Compatibility (EMC'09/Kyoto) 583 - 586 2009

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

Tohlu Matsushima, Keisuke Fukumasu, Tetsushi Watanabe, Yoshitaka Toyota, Kengo Iokibe, Ryuji Koga, Osami Wada

Proceedings of 2009 Korea-Japan Joint Conference on AP/EMC/EMT (KJJC-AP/EMC/EMT 2009) 187 - 190 2009

Band Elimination Characteristics of EBG Structure Containing High Permeability Ferrite Thin Films

Koichi Kondo, Shigeyoshi Yoshida, Hiroshi Ono, Yoshitaka Toyota

Proceedings of VIII International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology (EMC'2009) 151 - 153 2009

Combination of IBIS and LECCS-core Models for SI Analysis under Non-Ideal Power Supply Conditions

Norimasa Oka, Kengo Iokibe, Yoshitaka Toyota, Ryuji Koga

Proceedings of 2009 Korea-Japan Joint Conference on AP/EMC/EMT (KJJC-AP/EMC/EMT 2009) 159 - 162 2009

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

Tohlu Matsushima, Keisuke Fukumasu, Tetsushi Watanabe, Yoshitaka Toyota, Kengo Iokibe, Ryuji Koga, Osami Wada

Proceedings of 2009 Korea-Japan Joint Conference on AP/EMC/EMT (KJJC-AP/EMC/EMT 2009) 187 - 190 2009

Reduction of EMI from Differential Signaling System Using Asymmetric Guard Trace

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

Proceedings of International Conference on Electronics Packaging 2009 (ICEP2009) 718 - 723 2009

EMI Macro Modeling of Driver Circuits Using Static Characteristics of Transistors

OKA Norimasa, IOKIBE Kengo, TOYOTA Yoshitaka, KOGA Ryuji

The IEICE transactions on communications B J92-B ( 1 ) 287 - 295 2009

Evaluation of Multiple Power-Supply Pin LECCS-core Model with Different Pattern Design Boards

HIGASHI Ryota, IOKIBE Kengo, TSUDA Takahiro, ICHIKAWA Kouji, NAKAMURA Katsumi, TOYOTA Yoshitaka, KOGA Ryuji

IEICE technical report 108 ( 132 ) 43 - 48 2008.7

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

We have proposed an EMC macro model, LECCS, to achieve fast simulations of RF power currents in IC/LSIs. The model consists of linear equivalent circuits with internal equivalent current sources. In this report, we discussed on the LECCS-core model of a 16-bit microcontroller with multiple power pins. RF power currents were measured with a model-evaluation board that is different from model-construction boards in terms of power traces. The measured currents were compared to simulated ones with the LECCS-core model and agreed within 4dB of error. The LECCS model was confirmed when in a condition that decoupling capacitors were removed. Power currents were still well simulated at each power pins as well as at a junction point where power lines meet in such decoupling conditions. We presented that the model simulates the RF power currents in good accuracy.

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Estimation of Electromagnetic Emissions from PCBs with a Connector through the Common-Mode Antenna Model (Part 2) : Model Improvement by Considering Connector Inductance

WAKADUKI Yuri, TORIGOE Makoto, WATANABE Tetsushi, TOYOTA Yoshitaka, IOKIBE Kengo, KOGA Ryuji

IEICE technical report 108 ( 132 ) 37 - 42 2008.7

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

In this paper, we apply a connector model with an inductance to the common-mode antenna model. The common-mode antenna model is able to estimate common-mode radiation from a printed circuit board (PCB) fast and with low calculation cost. The previous report described that the model estimated radiation from PCBs with interconnections, depending on pin configurations of the connector. However, the calculation did not follow the frequency shift depending on pin configuration. The shift seems to result from the effective inductance of connector pins. Therefore, we developed the model considering the inductance. It was found that the modified common-mode antenna model with the connector inductance followed the frequency shift of radiation spectrum. As a result, the radiation spectrum obtained from the modified common-mode antenna model has good agreement with the measured spectrum within an error of 2dB.

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B-4-37 Experimental Verification of Electromotive Force of Common-mode Defined in Imbalance Difference Mechanism

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

Proceedings of the IEICE General Conference 2008 ( 1 ) 346 - 346 2008.3

Modeling of Microcontroller with Multiple Power Supply Pins for Conducted EMI Simulations

Kengo Iokibe, Ryota Higashi, Takahiro Tsuda, Kouji Ichikawa, Katsumi Nakamura, Yoshitaka Toyota, Ryuji Koga

IEEE EDAPS: 2008 ELECTRICAL DESIGN OF ADVANCED PACKAGING AND SYSTEMS SYMPOSIUM 135 - + 2008

Language：English Publisher：IEEE

An EMC macro-model of a 16-bit microcontroller with multiple-power-supply pins has been proposed for estimating the conducted EMI from a power-supply network. The macro-model, called the linear equivalent circuit and current sources (LECCS) model, is composed of multiple circuit blocks and multiple current sources corresponding to the composition of the chip circuits in the microcontroller, i.e., a current source for a circuit block. A current source statistically expresses the total RF current occurring in the corresponding circuit block. We confirmed that the proposed model could correctly estimate the RF power-supply currents under different decoupling conditions up to 300 MHz. We also found that a linear circuit of the regulator between the I/O and core circuit blocks could express the RF coupling between the two blocks.

DOI： 10.1109/EDAPS.2008.4736018

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Determination of Grounding Location for Guard Trace to Reduce Common-Mode Radiation

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

Proceedjngs of International Conference on Electronics Packaging 2008 (ICEP 2008) 124 - 129 2008

Prediction of the Common-mode Radiated Emission from the Board to Board Interconnection through Common-mode Antenna Model

Makoto Torigoe, Akifumi Sadatoshi, Yoshitaka Toyota, Kengo Iokibe, Ruji Koga, Tetsushi Watanabe, Osami Wada

2008 IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, VOLS 1-3 498 - + 2008

Language：English Publisher：IEEE

In this paper, the common-mode antenna model, which can estimate the amount of common-mode radiation quickly and accurately, was applied to a board-to-board interconnection structure with a connector. The inductor model is introduced as the connector model for improving accuracy of the common-mode antenna model. By using the inductance, which was calculated with the commercial electromagnetic field simulator, the radiated emissions estimated by the model agreed with the measurement results within an error of 3 dB around the peak emission levels.

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EMC Macro-modeling of CMOS Inverter Using LECCS-I/O Model with Additional Current Source

Kengo Iokibe, Akihiro Ohsaki, Yoshitaka Toyota, Ryuji Koga, Osami Wada

2008 IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, VOLS 1-3 554 - + 2008

Language：English Publisher：IEEE

The authors investigated an EMC macro-model of the CMOS logic inverter gate, named LECCS-I/O that consists of linear equivalent circuit and current sources. This paper modifies the macro-model by adding another current source to express the short-circuit current in the inverter. The macro-model was determined from SPICE calculations of impedance and power current by using a device model of an inverter IC. The modified model was tested with several load capacitances in SPICE simulation. The results showed that the macro-model predicts the power current with good accuracy in the range up to 3 GHz except for frequencies at which inductances of the package and of traces on printed circuit board and capacitance of the load caused resonances.

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Macro Model of Driver Circuits for EMI Simulation

Norimasa Oka, Kengo Iokibe, Yoshitaka Toyota, Ryuji Koga

Proceedjngs of International Conference on Electronics Packaging 2008 (ICEP 2008) 467 - 472 2008

Experimental Validation of Imbalance Difference Model to Estimate Common-Mode Excitation in PCBs

Yoshitaka Toyota, Tohlu Matsushima, Kengo Iokibe, Ryuji Koga, Tetsushi Watanabe

2008 IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, VOLS 1-3 578 - + 2008

Language：English Publisher：IEEE

We have proposed a common-mode antenna model that is designed specifically for estimating common-mode radiation from printed circuit boards (PCBs) very quickly. The model is composed of an antenna that has the same geometry as the adjacent ground plane of the PCB and an excitation source based on an imbalance difference model. The excitation source is provided by the product of Delta h and V-N, where Delta h is the difference in current division factors related to the cross-sectional structure of the transmission line, and VN is the voltage between the signal line and return plane of the transmission line. Here, we describe an experimental validation of the common-mode excitation carried out by measuring the reduction in radiation due to a guard trace placed close to a signal line with a narrow return plane. As a result, it was found that the total common-mode excitation can be given by a superposition of two excitation sources. The results also suggest that when designing the PCB, the guard trace should be grounded at the interface between different ground-plane widths to suppress noise.

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EMI simulation based on cavity-mode model for power-bus radiation calculation of power/ground planes with IC/LSI

Yoshitaka Toyota, Masahiro Nishida, Kengo Iokibe, Ryuji Koga, Osami Wada

2008 ASIA-PACIFIC SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY AND 19TH INTERNATIONAL ZURICH SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, VOLS 1 AND 2 423 - + 2008

Language：English Publisher：IEEE

This paper describes an electromagnetic interference (EMI) simulation of radiated emissions caused by simultaneous switching noise in an irregular power/ground plane structure. For quick simulation of the radiated emissions from the power-bus edges, we used a series of analytical approaches: power-bus resonance characterization by a fast algorithm based on a cavity-mode model and a segmentation method and radiation calculation using equivalent magnetic current based on the field equivalent principle. The analytically based radiation calculation is achieved within a few minutes on a single personal computer and agrees with the actual measurements. Furthermore, this paper demonstrates an EMI simulation with and without decoupling capacitors by using a linear macro model of an integrated circuit as a noise source. We found a fair agreement between the simulation and measured results.

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Suppressing power bus resonance and radiation using and EBG structure

Yoshitaka Toyota, Kengo Iokibe, Ryuji Koga, Koichi Kondo, Shigeyoshi Yoshida

2008 ASIA-PACIFIC SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY AND 19TH INTERNATIONAL ZURICH SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, VOLS 1 AND 2 566 - + 2008

Language：English Publisher：IEEE

We investigated the effects of noise suppression by interposing magnetic materials between the power and ground planes of a printed circuit board and focused on RF transmission through and radiation from the power bus. To reduce power bus resonance and radiation, we used a commercial noise suppression sheet, which is commonly used to suppress RF noise generated from electronic devices. We also examined a thin Ni-Zn ferrite film for practical use in the future. We found that power bus resonance and radiation could be mitigated owing to the imaginary part of complex permeability of magnetic materials. The thin ferrite film with a planar electromagnetic bandgap (EBG) structure helped suppress transmission and radiation in the EBG passband.

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B-4-25 EMC macro-modeling of CMOS inverter with two equivalent current sources

Iokibe Kengo, Osaki Akihiro, Toyota Yoshitaka, Koga Ryuji, Wada Osami

Proceedings of the IEICE General Conference 334 334 - 334 2008

B-4-30 Suppression of Power Bus Resonance and Radiation by High-Permeability Magnetic Metal Sheet Interposed between Power/Ground Planes of Printed Circuit Board

Toyota Yoshitaka, Iokibe Kengo, Koga Ryuji, Kondo Koichi, Yoshida Shigeyoshi

Proceedings of the IEICE General Conference 339 - 339 2008

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