DOUBLE CURRENT CONTROLLED CFA (DCC-CFA) BASED VOLTAGE-MODE OSCILLATOR WITH INDEPENDENT ELECTRONIC CONTROL OF OSCILLATION CONDITION AND FREQUENCY

Roman Šotner – Norbert Herencsár – Jan Jeřábek – Radek Dvořák –
Aslihan Kartci – Tomáš Dostál – Kamil Vrba

   In this paper, a new electronically tunable quadrature oscillator (ETQO) based on two modified versions of current feedback amplifiers (CFAs), the so called double current controlled CFA (DCC-CFAs) is presented. The frequency of oscillation (FO) of the proposed voltage-mode (VM) ETQO is electronically adjustable by current gain or by varying the intrinsic resistance of the X terminal of the active element used. The condition of oscillation (CO) is adjustable by current gain independently with respect to frequency of oscillation. Simultaneous control of current gain and intrinsic resistance allows linear control of FO and provides extension of frequency tuning range. In the proposed circuit all the capacitors are grounded. The use of only grounded capacitors makes the proposed circuit ideal for integrated circuit implementation. The presented active element realized by using BiCMOS technology and the behavior of proposed circuit are discussed in details. The theoretical results are verified by SPICE simulations based on CMOS ON-Semi C5 0.5 μm and bipolar ultra high frequency transistor arrays Intersil HFA 3096 process parameters.

Keywords: electronic control, sinusoidal oscillator, current feedback amplifier (CFA), double current controlled CFA (DCC-CFA)

[full-paper]