Takanori Uno

Development of a Low EMI Micro-controller Package for Automobile Applications

For ECUs the common-mode current is the main cause of EMI problems. In this paper, the mechanism of common-mode current generation and an effective way to reduce it is considered theoretically. From the consideration it is obtained that the common-mode current caused by the differential-mode current can be suppressed by means of adjusting the impedance of a PCB to be balancing adequately. And a package in which the impedance adjusting circuit and oscillator circuit is implement is developed for a micro-controller. The measurement shows that the developed package can reduce the common-mode current generation compared to the conventional QFP package. And the developed package can minimize the value of the common-mode current by means of adjusting the inductance of the power bus line in the package.

Novel design technique for reducing common-mode current on wire harness connected to ECUs

A key parameter that controls common-mode cur- rent on the cable connected to electronic control units (ECUs) is investigated. Supply currents for the CPU on ECUs and parasitic inductance / capacitance of supply traces on printed circuit boards (PCBs) generate common-mode current on the cable. We found the amount of common-mode current can be reduced sensitively by adjusting the balance of parasitic inductance / capacitance. The new approach proposed in this paper allows minimizing the common-mode current and suppress the radiation less than the currently achievable level. This technique is proven experimentally with evaluation boards and the influence of these parameters on common-mode current is confirmed by our simulation technique. I. INTRODUCTION Nowadays, a driving speed of LSI is getting faster and it is equipped on electronic device denser than past one. According to these situations, electromagnetic radiation from electronic devices becomes larger and it gives harmful influence on electronic devices such as jamming of radio communication or miss action of its circuits. Especially in automobile, EMI/EMC becomes very serious problem because many electronic de- vices are equipped together with a radio in a car. The origin of electromagnetic radiation emitted from electronic device is voltage fluctuation and high frequency current that are exited when LIS is driving. These voltage fluctuation and high fre- quency current drive printed circuit boards (PCBs), their frame and cable attached to them as antennas and electromagnetic wave is radiated from them. At VHF (30∼300MHz) frequency

An approach for practical use of common-mode noise reduction technique for in-vehicle electronic equipment

In this paper, we studied the use of common mode noise reduction technique for in-vehicle electronic equipment in an actual instrument design. We have improved the model circuit of the common mode noise that flows to the wire harness to add the effect of a by-pass capacitor located near an LSI. Moreover, to satisfy the noise reduction equation composed of numerous parameters, we proposed a design technique using an optimization algorithm and an electromagnetic field simulator, and confirmed its effectiveness.

An optimization system with parallel processing for reducing electromagnetic interference on electronic control unit

In this paper, we propose an optimization system with parallel processing for reducing electromagnetic interference (EMI) on electronic control unit (ECU). We adopt simulated annealing (SA), genetic algorithm (GA) and taboo search (TS) to seek optimal solutions, and a Spice-like circuit simulator to analyze common-mode current. Therefore, the proposed system can determine the adequate combinations of the parasitic inductance and capacitance values on printed circuit board (PCB) efficiently and practically, to reduce EMI caused by the common-mode current. Finally, we apply the proposed system to an example circuit to verify the validity and efficiency of the system.