Ultra low power cmos phase-locked loop frequency synthesizers
Vamshi Krishna Manthena
Date of Issue2011
School of Electrical and Electronic Engineering
Centre for Integrated Circuits and Systems
With the increasing demand for low cost and high integration of wireless transceiver building blocks, the low-power performance is a great concern for radio-frequency integrated circuit (RFIC) designers. Intensive effort has been made to develop RF integrated circuits and systems in the gigahertz range using the low-cost CMOS process. The commonly used frequency synthesizer based on the phase-locked loop (PLL) is an important building block of the transceiver. The frequency synthesizer, which performs the main role of carrier generation for the down-conversion/up-conversion operations, is a major and critical block of a wireless transceiver because it operates at high frequency and consumes a very large portion of the total power consumption in the transceiver. The performance in power consumption and channel selection of frequency synthesizer are limited by the two most important building blocks, namely the voltage-controlled oscillator (VCO) and the high frequency divider. The objective of this research work is to design the critical blocks for the frequency synthesizer with low power consumption. In this thesis, we have carried a detailed analysis on the speed and power consumption of the digital dividers and developed low power prescalers based on the dynamic logic. A CMOS fully programmable 1 MHz resolution divider for Zigbee and IEEE 802.15.4 applications is implemented based on pulse-swallow topology which uses the proposed ultra-low power 2/3 prescaler, low power 47/48 prescaler and a reloadable D flip-flop for the counters. A detailed design of wide-band 2/3 prescaler based on dynamic logic is presented which is suitable for IEEE 802.11 a/b/g applications and also verified in the design of fully programmable Multi-band divider which provides flexible resolution.
DRNTU::Engineering::Electrical and electronic engineering::Integrated circuits