Autors: Pandiev, I. M.
Title: Stability Analysis and Design of Wideband Howland Current Pumps Using Monolithic Current-Feedback Amplifiers
Keywords: Analog circuits, Cutoff frequency, Resistors, Stability analysis, Operational amplifiers , Transfer functions

Abstract: This paper focuses on the stability analysis of wideband improved Howland currents pumps using monolithic current-feedback operational amplifiers (CFOAs). Based on the application of the Nyquist criterion the possibilities of CFOAs for stable operation in the current pumps at output current iL larger than 1 mA and upper cut-off frequency f-3dB higher than 100 kHz are investigated. Formulas for closed loop gain T=β+ A F− of the system with positive and negative feedback at active and complex load are presented. The complex coefficients of the amplifier circuit AF and the positive feedback ß+ are determined by using equivalent circuits based on the high frequency CFOA model, taking into account the input impedances, one-pole transfer function, output impedance and parasitic board capacities. Mathematical formulas for the poles and zeros based on the obtained coefficients are derived. Moreover, using these formulas a design procedure of improved Howland currents pumps are proposed.

References

    Issue

    2018 41st International Spring Seminar on Electronics Technology (ISSE), pp. 1-7, 2018, Serbia, ISBN 978-1-5386-5731-7

    Вид: публикация в международен форум, публикация в реферирано издание, индексирана в Scopus