Design and Application of CMOS DLL in Delay Generator and PWCL
Date Issued
2007
Date
2007
Author(s)
Wu, Hsin-Yi
DOI
en-US
Abstract
As the development in VLSI systems, the demands of high frequency applications increase dramatically. Therefore, the precise delay generator, the synchronization problem, and programmable duty cycles are becoming important but choke points for high performance systems.
This thesis is divided into two parts. The first part of the research is on delay generators. In order to generate precise phases, the resolution of delay generator enhancement is essential. In this work, we propose a precise delay generator circuit using an average delay technique. With the proposed technique, we can use not only smaller chip areas to achieve low power and a high resolution delay generator, but also the average delay technique to get a variable delay time, not a fixed one. The delay generator is realized in 0.18-μm CMOS 1P6M technology. The input frequency is 400MHz and the resolution is 25ps. Under a supply voltage of 1.8V, the whole chip ,which occupies the area of 0.747×0.785mm2 ,dissipates a power of 17mW.
The second part of the research is on pulsewidth control loops (PWCL). In a high speed operation, the phase and the duty cycle are important information in a system. In this work, a pulsewidth control loop with a programmable duty cycle using a wide range DLL is realized in 0.18-μm CMOS 1P6M technology. Based on the proposed circuit, not only the programmable duty cycle of the clock can be generated but also the phase alignment between the input and output clocks can be achieved. The duty cycle of the output clock can be adjusted from 30% to 70% in steps of 5%. The input frequency is from 400MHz to 1.6GHz. In order to work in a wide range of operations, a fast locking started-controlled circuit (FLSC) is proposed to solve the harmonic problem in a DLL.
Subjects
延遲產生器
脈波寬度控制迴路
可變工作週期
寬範圍
起始控制電路
Delay Generator
Delay Locked Loop(DLL)
programmable duty cycle
wide range
start-controlled circuit
Type
thesis