National Chiao-Tung University

Department of Electronics Engineering & Institute of Electronics





An All-Digital Wide Power Supply Range And Wide Frequency Range DLL-Based clock Generator






Student : Yi-Ming Chang

Advisor : Dr. Wei Hwang



Abstract

An all-digital wide power supply range wide frequency range DLL-based clock generator is proposed in this thesis. In order to operate in wide power supply range, the robust circuit methodology is used in this design. Besides, an adaptive successive approximation register-controlled (ASAR) search algorithm is proposed to extend the locking range and avoid harmonic lock at the same time. An ASAR based controlled is adopted in multiphase DLL implemented in UMC 90nm CMOS technology. The simulation results show that, the operating frequency is from 250MHz to 1.25GHz at 1.0V, and 13MHz to 75MHz at 0.3V, respectively.

A 125MHz-2.5GHz all-digital DLL-based clock generator has been designed in UMC 90nm CMOS technology. In order to achieve dynamic frequency/voltage scaling application, the robust and programmable frequency multiplier is proposed. Besides, the novel leakage-reduced delay unit is proposed to take advantages of mitigating 10% leakage current, insensitive to PVT variations, and not degrading operating frequency of circuit. The simulation results show the proposed DLL-based clock generator exhibits maximum power dissipation 0.71mW when operate in 500MHz, generating 250MHz, 500MHz, 1GHz, and 2GHz four different frequency at the same time. The presented DLL clock generator can be robustly used in embedded memory applications and portable device.