Power Integration And EMC Analysis For Power/Ground Plane In High Speed Circuit System

In recent years, IC integration scale and high-speed IC grow very fast. With the development of silicon based CMOS technology, IC sizes and integration scale become larger and working frequency is higher than 1GHz, working voltages become smaller, all these cause the power consumption much smaller. The signal integrity problem is becoming more and more critical. Generally, signal integrity is referred to the interconnection effects in signal lines and package effects. There two ways which cause the signal integrity (SI) problems: the first one is through the signal lines; the second one is through simultaneous switching noise (SSN). The interconnection effects were largely studied in the past, while SSN becomes the hot topic recently. Therefore, this dissertation concentrates on the SSN study on the power/ground (P/G) plane pair structure in high-speed printed circuit boards (PCBs). This dissertation uses the traditional approach-eigenmode expansion method (EEM), and combines it with new method to analyze more complicated and practical shapes. Besides, this dissertation also studies the electromagnetic compatibility (EMC) problems caused by SSN. The contents are arranged as follows:Chapter 2 introduces eigenmode expansion method (EEM) and inverted composition method. Combine EEM and inverted composition method, EEM can be extended to plane pair structures with holes. To develop a low impedance P/G system, the fundamenta1 properties of P/G plane structures need to be explored at first. EEM is an efficient technique for characterizing a P/G plane pair structure. This dissertation is based on the method. However, the application of EEM is limited to the plane pair with regular shapes. To extend its application, this chapter introduces inverted composition method to EEM. Use the new method, the character of regular P/G plane pairs with holes can be presented.Chapter 3 introduces the Pade approximation method to EEM to improve the computation efficiency. Asymptotic waveform evaluation (AWE) is one of Pade approximation methods; it avoids numerous iteration calculations and saves the computation time. In order to approximate the function in the whole frequency domain, we apply complex frequency hopping (CFH) to EEM. To evaluate the SSN voltage on a P/G plane pairs, the FFT and IFFT techniques are employed,so it is necessary to calculate the impedance values on a large number of frequency points. Since the calculation process on every frequency point is similar,there are large amounts of iteration which may consume a lot of computation time. Therefore this chapter applies the AWE technique to EEM, deliver an expression of impedance as the function of frequency and calculate the impedance value and multi-order derivatives on one frequency point. Then the impedance value over a wide range can be evaluated. With CFH and AWE we can obtain the accurate solution over any specified variable range. The simulation results show that EEM combined with AWE and CFH has good accuracy and high efficiency.In chapter 4, we will analyze the EMC problems of the P/G plane of high-speed PCB circuit. Because of the existence of SSN, there is electromagnetic interference (EMI) in PCBs, the main causes and the ways to decrease these EMI problems will be analyzed in this chapter. The experiment and simulation results demonstrate the verity of EEM method in the study of high-speed circuit. In chapter 5, we will give a conclusion of what we have done. However, we still have more things to do in order to analyze SSN much better. Electromegnetic Bandgap Struture (EBG) is a good way to reduce SSN, many scholars from both home and abroad now focus on the subject. In the future, I will study this subject to efficiently solve the power integrity problems.