Fully Electronically Tunable and Easily Cascadable Square/Triangular Wave Generator with Duty Cycle Adjustment

A novel multiple-output dual-X current conveyor transconductance amplifier with buffer-based square/triangular wave generator is introduced in the paper. The proposed generator provides square wave in current mode and triangular wave in voltage mode. Outputs as square and triangular waves are available from terminals with appropriate impedance levels thereby making the proposed generator circuit easily cascadable in both current and voltage modes. The oscillation frequency and amplitude of output square wave are electronically and independently controllable. One more interesting feature of the proposed generator circuit is the adjustable duty cycle. The proposed circuit of square/triangular wave generator is verified through the HSPICE simulation results carried using 0.18 mu m CMOS technology. The simulation results show linear variation of duty cycle against external DC current over a range of 6.5 96%. The variation of square wave's amplitude via bias current is found to be linear from 10 mu A to 80 mu A. Moreover, the proposed generator can operate very well up to 23.8 MHz with nonlinearity less than 5%. The proposed generator circuit is also experimentally verified.