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

Abstract

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[Formula: see text][Formula: see text]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[Formula: see text][Formula: see text]A to 80[Formula: see text][Formula: see text]A. Moreover, the proposed generator can operate very well up to 23.8[Formula: see text]MHz with nonlinearity less than 5%. The proposed generator circuit is also experimentally verified.

Simple CMOS Square Wave Generator with Variable Mode Output

“…independent tuning of oscillation frequency; wide range of operating frequency; less complexity in terms of transistors count and low power consumption. The solution proposed in [18] also uses only one active element and offers a higher operation frequency range, but the deployed active element demands a bias voltage in currents for proper operation. Also, MO-CIDITA [18] possesses a much more complex internal structure with more MOS transistors then CCCII.…”

Design of Signal Generators Using Active Elements Developed in I3T25 CMOS Technology Single IC Package for Illuminance to Frequency Conversion

“…Generally, this method is useful and frequently used by researchers. Unfortunately, the obtained experimental results follow the trends from simulation of hypothetical CMOS internal structures rarely due to unsuitability of the off-the-shelf commercial AEs for the supposed operational bands (e.g., see [21]). Next, for different conditions, many recent works present more simulation-based results than measurement ones (high frequencies are unavailable in real cases due to high parasitic performances), see for example [21,22].…”

“…Unfortunately, the obtained experimental results follow the trends from simulation of hypothetical CMOS internal structures rarely due to unsuitability of the off-the-shelf commercial AEs for the supposed operational bands (e.g., see [21]). Next, for different conditions, many recent works present more simulation-based results than measurement ones (high frequencies are unavailable in real cases due to high parasitic performances), see for example [21,22]. Numerous experimental solutions [13,18,19,21] have really extensive circuitry because of implementation of commercially available AEs in behavioral model of the hypothetical AE.…”

“…Note that many researchers refer to the interconnection of the CCCII and OTA as current conveyor Many concepts use standard commercially available AEs (e.g., operational transconductance amplifiers (OTAs) [5,6], current conveyors [10], operational amplifiers [14,25], variable gain amplifiers [14,16,17], or their easily accessible models, i.e., internal topologies). In numerous works, the active subparts of basic building structures [2,3] are understood as a single element [7][8][9][11][12][13]15,[18][19][20][21][22][23]. It substantially changes view on the circuit and credibility of results when these concepts are presented as: (a) Simulated models only, (b) real so-called "behavioral models" [2,3] for experiments (based on off-the-shelf components), and (c) real fabricated complementary metal-oxide semiconductor (CMOS) cells encapsulated in a single integrated circuit (IC) package.…”

“…It substantially changes view on the circuit and credibility of results when these concepts are presented as: (a) Simulated models only, (b) real so-called "behavioral models" [2,3] for experiments (based on off-the-shelf components), and (c) real fabricated complementary metal-oxide semiconductor (CMOS) cells encapsulated in a single integrated circuit (IC) package. However, many AEs are used and designed on hypothetical level [7][8][9][11][12][13]15,[18][19][20][21][22]26] without fabrication in the form of IC. In fact, many of these devices include several functional active subparts.…”