Title :
A Supply Voltage and Temperature Variation-Tolerant Relaxation Oscillator for Biomedical Systems Based on Dynamic Threshold and Switched Resistors
Author :
Zhentao Xu ; Wei Wang ; Ning Ning ; Wei Meng Lim ; Yang Liu ; Qi Yu
Author_Institution :
State Key Lab. of Electron. Thin Films & Integrated Devices, Univ. of Electron. Sci. & Technol. of China, Chengdu, China
Abstract :
A fully integrated supply voltage and temperature variation-tolerant relaxation oscillator for biomedical systems has been presented. Concepts of dynamic threshold and switched resistors are proposed to improve the frequency stability against power supply and temperature variations, respectively. This design was verified in a 0.35-μm standard CMOS process with a 3 V supply. Measurement results show the frequency drift of 0.6% from 2.4 to 4.0 V and temperature stability of 53.9 ppm/°C as temperature varied from -30 °C to 120 °C at a typical working frequency of 4 MHz. With the consideration of resistor and transistor matching, the oscillator was implemented in a core area of 0.05 mm2.
Keywords :
CMOS analogue integrated circuits; biomedical electronics; circuit stability; frequency stability; relaxation oscillators; resistors; switched networks; transistors; biomedical system; frequency 4 MHz; frequency stability; fully integrated supply voltage; size 0.35 mum; standard CMOS process; switched resistor matching; temperature -30 degC to 120 degC; temperature variation-tolerant relaxation oscillator; transistor matching; voltage 2.4 V to 4.0 V; Capacitors; Circuit stability; Frequency measurement; Oscillators; Resistors; Temperature measurement; Thermal stability; Biomedical systems; clock generator; dynamic threshold (DT); frequency stability; relaxation oscillator; switched resistors (SRs); switched resistors (SRs).;
Journal_Title :
Very Large Scale Integration (VLSI) Systems, IEEE Transactions on
DOI :
10.1109/TVLSI.2014.2317722
