Texas Instruments (Japan)

Potential competing interests: No potential competing interests to declare.At present, the fusion of electric vehicles with renewable energy faces a shortage of data-supported practical solutions.Moreover, there's a noticeable lack of emphasis on refining the current model or conducting comparative analyses to stimulate advancements.The researchers delved into the evolution of cutting-edge technologies, outlining the path from AI-driven object detection systems to the seamless integration of renewable energy into electric vehicles.Initially, advancements in artificial intelligence, particularly in object detection, brought about a commendable revolution in real-time identification methods.

This study presents an extended Cauer circuit model of power inductors that can represent both eddy current effects and capacitive properties. This model is valid from DC to higher frequencies beyond the resonance because it considers the skin and proximity effects of windings as well as the parasitic capacitance. The inductive part is represented by a Cauer circuit whose circuit parameters are recursively determined from the frequency properties of the inductor obtained through measurements or simulations. Moreover, the impedance profile around the resonance is expressed by introducing hierarchical RLC series circuits to the Cauer circuit. The extended Cauer circuit can be embedded in circuit simulators once constructed to perform time-domain simulations.

This paper describes the kinetic and microstructural mechanism of electromigration (EM) failure found in low-profile solder joints where EM and intermetallic phase formation compete for the same volume of Sn. The low-profile solder joint used in our study was made of 20-25um thick solder situated in between a Cu pillar and a Ni coated Cu lead frame (LF). The samples were EM tested in a temperature range of 140-170oC with the current densities varying between 35-45 KA/cm2 in an oil bath to induce failure without Joule Heat induced artifacts. Our studies on EM failure kinetics and microstructural mechanism have produced two key findings. The first finding suggests that the EM diffusivity (Z*D) of diffusing species (Sn, Ni, Cu) in the solder matrix can be uniquely ranked from microstructural analysis, and it is estimated to be (Z*D) Cu> (Z*D) Sn>(Z*D) Ni. This difference in EM diffusivity causes Cu-Sn and Ni-Sn intermetallic compounds (IMC) to develop in distinctively different manners under EM, leading to different EM failure mechanisms. The second finding is that EM in low-profile solder joints consists of multiple failure stages: a) with EM-related voiding in Sn dominating at lower temperatures; while b) thermally-induced IMC growth and invasion competes with EM-induced Sn voiding at high temperatures leading to the complete failure of each joint.

This paper proposes a PFM+PWM hybrid controlled soft-switching half-bridge converter which has both benefit of conventional half-bridge converter and LLC converter. Generally, conventional half-bridge converter has good constant current characteristic due to PWM control, however it has some drawbacks of (1) primary side switches and secondary side diodes operate under hard switching, (2) two magnetic components. Meanwhile, the LLC resonant converter has the benefit of achieving ZVS and ZCS, however it can't realize a constant current (CC) characteristic because of resonant fashion. In order to achieve soft-switching and CC characteristic using half-bridge converter, a DCM operation are employed, which can be controlled by PWM+PFM Hybrid Control. In this paper the operating characteristics of the proposed half-bridge converter are experimentally verified. The experimental results for 48Vin, 16Vo, 80W board achieves 90% efficiency and validated this method is useful practically.

This paper investigates the fatigue crack growth behaviors of lead-free solder joints. Metallurgical interactions occur between solders and electrical pad metals in fabrication process and these intermetallic compounds continue to grow during service periods. Due to its brittle nature and lattice mismatch, the solder cracks tend to be generated near the compounds and these cracks affects the mechanical integrity of solder joints. Therefore, it is important to study the effect of intermetallic compounds development on the mechanical properties of the solder joints. In this paper, we focused on the low cycle fatigue of solder joints and investigate the effects of intermetallic compounds development on the fatigue life and the fatigue crack growth behavior of the solder joints.

Many types of electric equipments are digitized in recent years. However, the configuration of switch mode power supply is still only analog circuit because the analog circuit is held down to low cost. The digitized system is operated on the basis of a processor. When the switch mode power supply is treated as a part of the system, it is difficult that switch mode power supply inhabit alone in the system as the analog-circuit. Therefore, the digitization of the switch mode power supply is necessary to harmonize with other electronic circuits in the system. So far, various examinations have been discussed about digitally controlled switch mode power supplies[1-5]. However, important parameters such as the switching frequency were impractical because the performance of processor was not so good. Recently, due to the development of the semiconductor manufacture technology, the performance of processor such as DSP and FPGA is developed remarkably. Hence, the expectation of the practical realization in the digitally controlled switch mode power supply becomes higher. So far, in many case on digitally controlled switch mode power supply, the control system is constructed by very complicated, difficult modern control theory (nonlinear control theory) such as adaptive control or predictive control. Moreover, also in the most popular and easiest control method such as PID control, the design method is not so clear, and the optimal design is difficult[6, 7]. On the other hand, there are two methods of controller design. One is the digital direct design. The other is the digital redesign. The digital redesign method converts the analog compensator which is designed on s-region into digital compensator. The digital redesign method has some advantages. For example, the control system is designed from classical control theory (linear control theory). Therefore, many experiences and design techniques of the conventional analog compensator can be utilized. Moreover, from the practical stance, the digital redesign method is more realistic than digital direct design. This paper investigates the digitally controlled switch mode power supply by means of classical control theory. Especially, the interesting control technique which is cancelled the transfer function of the converter by using pole-zero-cancellation technique is introduced. This technique is very simple and stability design of converter system is very easy.

The fixed on-time with bottom detection control having ripple injection has become very attractive due to practical usage and realization of ceramic capacitor solution for output while keeping ultra fast transient response. This paper presents quantitative analysis by introducing averaging method in comparator operation for the transfer function. As a result, the frequency response characteristic was quantitatively revealed. Good agreements between theoretical results and actual measurements were obtained.

A high sensitivity and high full well capacity CMOS image sensor using active pixel readout feedback operation with positions of pixel select switch, operation timings and initial bias conditions has been reported. 1/3-inch 5.6-μm pixel pitch 800(H) x 600(V) color CMOS image sensors with the switch X set on or under the pixel SF have been fabricated by a 0.18-μm 2-Poly 3-Metal CMOS technology. The comparison of the active pixel readout feedback operation between two CMOS image sensors, which only have the deference of the switch X's position, has performed. As to the result, the switch X set on the pixel SF is favor for the active pixel readout feedback operation to improve the readout gain and the S/N ratio. This CMOS image sensor achieves high readout gain, high conversion gain, low input-referred noise and high full well capacity by the active pixel readout feedback operation.

A temperature-resistant 1/3 inch SVGA (800×600 pixels) 5.6 μm pixel pitch wide-dynamic-range (WDR) CMOS image sensor has been developed using a lateral-over-flow-integration-capacitor (LOFIC) in a pixel. The sensor chips are fabricated through 0.18 μm 2P3M process with totally optimized front-end-of-line (FEOL) & back-end-of-line (BEOL) for a lower dark current. By implementing a low electrical field potential design for photodiodes, reducing damages, recovering crystal defects and terminating interface states in the FEOL+BEOL, the dark current is improved to 12 e- /pixel-sec at 60 deg.C with 50% reduction from the previous very-low-dark-current (VLDC) FEOL and its contribution to the temporal noise is improved. Furthermore, design optimizations of the readout circuits, especially a signal-and noise-hold circuit and a programmable-gain-amplifier (PGA) are also implemented. The measured temporal noise is 2.4 e-rms at 60 fps (:36 MHz operation). The dynamic-range (DR) is extended to 100 dB with 237 ke- full well capacity. In order to secure the temperature-resistance, the sensor chip also receives both an inorganic cap onto micro lens and a metal hermetic seal package assembly. Image samples at low & high temperatures show significant improvement in image qualities.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.