CCII-based balanced fully integrated continuous-time current-mode filter synthesis: signal-flow graph approach

2002 ◽  
Author(s):  
S. Ozoguz ◽  
E.O. Gunes ◽  
H.O. Elwan ◽  
T.B. Tarum
Keyword(s):  
Continuous Time ◽  
Current Mode ◽  
Signal Flow Graph ◽  
Flow Graph ◽  
Fully Integrated ◽  
Signal Flow ◽  
Filter Synthesis

Signal Flow Graph Synthetical Implement the Current-Mode Multifunction Filter Based on CDTA

2014 ◽  
Vol 530-531 ◽  
pp. 1100-1107
Author(s):  
Hai Zhen He ◽  
Jun Kuang ◽  
Xin Liu ◽  
Xin Hang Huang ◽  
Mei Li Cao
Keyword(s):  
Integrated Circuit ◽  
Current Mode ◽  
Signal Flow Graph ◽  
Flow Graph ◽  
Signal Flow ◽  
Transconductance Amplifier ◽  
Multifunction Filter ◽  
Component Matching ◽  
Current Differencing Transconductance Amplifier ◽  
High Output

In this paper, a signal flow graph structure of current-mode multifunction filter using current differencing transconductance amplifier (CDTA) is presented. The proposed configuration is comprised of two grounded capacitors and four CDTAs. They exhibit low-input and high-output impedances, which is very convenient for integrated circuit implementation. The presented filter configuration can realize all the standard filter functions simultaneously, lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP), without any component matching conditions. The natural frequency () and the bandwidth () of the proposed filter can be electronically tuned by varying the bias current of the CDTA. PSPICE simulation results are included to confirm the theory.

scholarly journals Log-domain electronically-tuneable fully differential high order multi-function filter

2020 ◽  
Vol 10 (2) ◽  
pp. 1263
Author(s):  
Osama O. Fares
Keyword(s):  
Current Mode ◽  
Signal Flow Graph ◽  
Flow Graph ◽  
Signal Flow ◽  
Fully Differential ◽  
Low Pass ◽  
Band Pass ◽  
Simulation Results ◽  
Log Domain ◽  
High Pass

This paper presents the synthesis of fully deferential circuit that is capable of performing simultaneous high-pass, low-pass, and band-pass filtering in the log domain. The circuit utilizes modified Seevinck’s integrators in the current mode. The transfer function describing the filter is first presented in the form of a canonical signal flow graph through applying Mason’s gain formula. The resulting signal flow graph consists of summing points and pick-off points associated with current mode integrators within unity-gain negative feedback loops. The summing points and the pick-off points are then synthesized as simple nodes and current mirrors, respectively. A new fully differential current-mode integrator circuit is proposed to realize the integration operation. The proposed integrator uses grounded capacitors with no resistors and can be adjusted to work as either lossless or lossy integrator via tuneable current sources. The gain and the cutoff frequency of the integrator are adjustable via biasing currents. Detailed design and simulation results of an example of a 5th order filter circuit is presented. The proposed circuit can perform simultaneously 5th order low-pass filtering, 5th order high-pass filtering, and 4th order band-pass filtering. The simulation is performed using Pspice with practical Infineon BFP649 BJT model. Simulation results show good matching with the target.

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