New single-resistance-controlled oscillator configurations using unity-gain cells
Unity-gain voltage followers and unity-gain current followers have attracted attention in the recent literature in the context of analog signal processing as well as signal generation because of the advantages of wider bandwidth and low power consumption of these active elements as compared to other more complex building blocks. Motivated by these advantages, followers have been used as alternatives to other more complex building blocks in the realisation of filters, oscillators and more recently, in impedance converters. Although some configurations for realizing sinusoidal oscillators using unity-gain voltage/current followers have been described in the earlier literature, only one of them is a second-order single-resistance-controlled oscillator but requires as many as eight followers. This paper derives, through a state-variable synthesis approach, a number of new follower-based single-resistance-controlled oscillators requiring a much smaller number (only two to four) of followers. The new circuits are shown to possess a number of other interesting features. The workability of the new structures has been confirmed by SPICE simulation results using CMOS-based followers.
voltage followers current followers sinusoidal oscillators analog circuits current-mode circuits