CMOS ring oscillator delay cell performance: a comparative study

Abstract

A common voltage-controlled oscillator (VCO) architecture used in the phase locked loop (PLL) is the ring oscillator (RO). RO consist of number of inverters cascaded together as the input of the first stage connected to the output of the last stage. It is important to design the RO to be work at desired frequency depend on application with low power consumption. This paper presents a review the performance evaluation of different delay cell topologies the implemented in the ring oscillator. The various topologies analyzed includes current starved delay cell, differential delay cell and current follower cell. Performance evaluation includes frequency range, frequency stability, phase noise and power consumption had been reviewed and comparison of different topologies has been discussed. It is observed that starved current delay cell have lower power consumption and the different of the frequency range is small as compared to other type of delay cell.

Design and simulation of high frequency colpitts oscillator based on BJT amplifier

“…These oscillators can be used in many applications such as clock generation for digital electronics, switching waveform for switch mode power supply. Wien bridge oscillator is mostly used for about 1 MHz range [8]. LC oscillator can be used for high frequency in most applications of electronic and communication circuits and systems [9,10].…”

“…By sub (8). in(6) 48 I B -0.163 x 10 -3 -39 I B = I B 48 I B -39 I B -IB = 0.163 mA 8 I B = 0.163 mA I B = 0.0204 mA, I B = 20.4 µA I b1 = 48 I B = 48 x 20.4 µA = 0.0979 mA Ic = β I B = 156 x 20.4 µA 3.2 mA By applying KVL on base circuit of Figure 2 so that: kΩ Applying KVL on collector circuit of Figure 1 so that: VCE = Vcc -Ic (Rc + R E ) VCE = 3.5 v 3.5 = 12 -βI B (Rc + R E ) βI B (Rc + R E ) = 12-3.5 156 x 0.0204 x 10 -3 (Rc + 1 kΩ) = 12 -3.5 3.1824 + 3.1824 Rc x 10 -3 = 8.5 3.1824 Rc x 10 -3 = 8.5 -3.1824 = 5.3176 Rc = = 1.6709 kΩFinally, the complete circuit of proposal design is clear inFigure 3.…”

High-performance combined ring oscillators

“…So, large-signal analysis is needed for accurate calculations of the steady-state behavior of the oscillator (Oukaira et al, 2017). So delay calculations are the most important part of ring oscillator analysis (Zafarkhah et al, 2017;Suman et al, 2016;Qiu et al, 2017;Hadi et al, 2019;. The frequency oscillation value is determined only by delay times of inverters and a number of stages.…”