The Experts below are selected from a list of 840 Experts worldwide ranked by ideXlab platform
Hio Leong Chao - One of the best experts on this subject based on the ideXlab platform.
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CMOS variable-gain wide-bandwidth CMFB-free differential Current Feedback Amplifier for ultrasound diagnostic applications
2006 IEEE International Symposium on Circuits and Systems, 2006Co-Authors: Hio Leong ChaoAbstract:A CMOS Current Feedback Amplifier (CFA) for ultrasound diagnostic applications is described in this paper. Unlike traditional CFA designs, this design proposes a new symmetrical circuit architecture which does not require extra common-mode Feedback circuitry. The design employs active Feedback to enhance the gain-bandwidth independence. Miller compensation is adopted for better frequency response and smaller on-chip capacitor. The CFA has been designed with TSMC 0.35 mum CMOS process. The active layout area is 0.052 mm2. HSPICE post-layout simulation shows that the CFA exhibits a bandwidth of 10.7 MHz for a variable voltage gain range of 6 dB to 60 dB, with a supply of 3.3 V and a power dissipation of 2.4 mW. Compared to CFA design without active Feedback, the bandwidth variation is reduced by 8 times
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ISCAS - CMOS variable-gain wide-bandwidth CMFB-free differential Current Feedback Amplifier for ultrasound diagnostic applications
2006 IEEE International Symposium on Circuits and Systems, 2006Co-Authors: Hio Leong Chao, Dongsheng MaAbstract:A CMOS Current Feedback Amplifier (CFA) for ultrasound diagnostic applications is described in this paper. Unlike traditional CFA designs, this design proposes a new symmetrical circuit architecture which does not require extra common-mode Feedback circuitry. The design employs active Feedback to enhance the gain-bandwidth independence. Miller compensation is adopted for better frequency response and smaller on-chip capacitor. The CFA has been designed with TSMC 0.35 /spl mu/m CMOS process. The active layout area is 0.052 mm/sup 2/. HSPICE post-layout simulation shows that the CFA exhibits a bandwidth of 10.7 MHz for a variable voltage gain range of 6 dB to 60 dB, with a supply of 3.3 V and a power dissipation of 2.4 mW. Compared to CFA design without active Feedback, the bandwidth variation is reduced by 8 times.
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CMOS Low-Power Variable-Gain CMFB-Free Current Feedback Amplifier for Ultrasound Diagnostic Applications
2006 IEEE Asian Solid-State Circuits Conference, 2006Co-Authors: Hio Leong Chao, Mike Koen, Paul PrazakAbstract:A CMOS Current Feedback Amplifier (CFA) for ultrasound diagnostic applications is proposed. Unlike traditional CFAs, this design employs a new symmetrical and compact architecture, without the use of common-mode Feedback (CMFB) circuitry. The design proposes an active Feedback technique to drastically enhance the gain-bandwidth independence. It is also the first CFA to adopt Miller compensation for better frequency response with smaller compensation capacitor. The proposed CFA was fabricated and tested with a standard 0.35 mum CMOS process with competitive performance to its Bipolar and BiCMOS counterparts. The active die area is 0.052 mm2. Experiment results show that the CFA exhibits a minimum bandwidth of 4.5 MHz with a variable gain range of 0 to 46 dB, and a power dissipation of 2.18 mW.
Eduard Alarcon - One of the best experts on this subject based on the ideXlab platform.
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fast transient Current steering cmos ldo regulator based on Current Feedback Amplifier
Integration, 2013Co-Authors: Alireza Saberkari, Eduard Alarcon, Shahriar B ShokouhiAbstract:This paper presents a Current-steering approach to implement a fast transient response low-dropout regulator (LDO) based on a Current Feedback Amplifier (CFA) topology. The circuit does not require any internal compensation capacitor, being stable for a wide range of output load Currents [0-100mA] and a 1@mF output capacitor. The CFA consists of an open-loop voltage follower with output local Current-Current Feedback based on a level-shifted flipped voltage follower (LSFVF) which is instrumental to achieve high regulation and fast transient response. The inverting output buffer stage of the CFA together with Current-mirror-based driving of the power pass transistor results in high PSRR. Post-layout simulation results for a 0.35@mm CMOS process design reveal that the proposed LDO requires 59@mA quiescent Current at no-load condition and at full-load condition has a Current efficiency of 99.8%. For a 1@mF output capacitor, the maximum output voltage variation to a 0-100mA load transient with rise and fall times of 10 and 100ns is only 3mV, and the PSRR is smaller than -56dB over the entire load Current range.
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Fast transient response CFA-based LDO regulator
2012 IEEE International Symposium on Circuits and Systems (ISCAS), 2012Co-Authors: Alireza Saberkari, Herminio Martinez, Eduard AlarconAbstract:In this paper a fast transient response low-dropout regulator (LDO) based on a Current Feedback Amplifier (CFA) is presented. The utilized CFA consists of an open-loop voltage follower with output local Current-Current Feedback based on a level-shifted flipped voltage follower (LSFVF) to achieve high regulation and fast transient response. The inverting output buffer stage of the CFA together with Current-mirror-based driving of the power pass transistor results in high PSRR. The circuit does not require any internal compensation capacitor and is stable for a wide range of output load Currents 0-100 mA and a 1μF output capacitor. Post-layout simulation results for a 0.35μm CMOS process reveal that the maximum output voltage deviation of the proposed LDO for 0-100mA load transient with rise and fall times of 10 and 100ns is only 3mV, and the PSRR is smaller than -56dB over the entire load Current range.
Alireza Saberkari - One of the best experts on this subject based on the ideXlab platform.
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Design and Implementation of a Sliding-Mode Controller for Low-Dropout/Linear Regulator
IEEE Transactions on Circuits and Systems II: Express Briefs, 2018Co-Authors: Javad Bagheri, Alireza Saberkari, Omid Khorgami, Eduard Alarcón-cotAbstract:This brief presents an approach to utilize of sliding-mode (SM) controller in digital low-dropout/linear regulators. Various design aspects, including the extraction of the regulator state-space model and sliding coefficients by considering the hitting, existence, and stability conditions are described. Moreover, the freeze control block is introduced as a solution to compensate for the high frequency chattering phenomenon of SM, resulting in reduction of switching losses. In order to verify the statements, a quasi digital low-dropout/linear regulator is implemented in a discrete form on a PCB. The circuit consists of the proposed Current-mode Current Feedback Amplifier-based SM controller and switched-mode pMOS array driven by a bidirectional serial shift register, which is controlled by the SM controller. The results reveal that the controller detects the load changes rapidly, and eliminates the output limit-cycle oscillation, providing a robust and stable output voltage.
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fast transient Current steering cmos ldo regulator based on Current Feedback Amplifier
Integration, 2013Co-Authors: Alireza Saberkari, Eduard Alarcon, Shahriar B ShokouhiAbstract:This paper presents a Current-steering approach to implement a fast transient response low-dropout regulator (LDO) based on a Current Feedback Amplifier (CFA) topology. The circuit does not require any internal compensation capacitor, being stable for a wide range of output load Currents [0-100mA] and a 1@mF output capacitor. The CFA consists of an open-loop voltage follower with output local Current-Current Feedback based on a level-shifted flipped voltage follower (LSFVF) which is instrumental to achieve high regulation and fast transient response. The inverting output buffer stage of the CFA together with Current-mirror-based driving of the power pass transistor results in high PSRR. Post-layout simulation results for a 0.35@mm CMOS process design reveal that the proposed LDO requires 59@mA quiescent Current at no-load condition and at full-load condition has a Current efficiency of 99.8%. For a 1@mF output capacitor, the maximum output voltage variation to a 0-100mA load transient with rise and fall times of 10 and 100ns is only 3mV, and the PSRR is smaller than -56dB over the entire load Current range.
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Fast transient response CFA-based LDO regulator
2012 IEEE International Symposium on Circuits and Systems (ISCAS), 2012Co-Authors: Alireza Saberkari, Herminio Martinez, Eduard AlarconAbstract:In this paper a fast transient response low-dropout regulator (LDO) based on a Current Feedback Amplifier (CFA) is presented. The utilized CFA consists of an open-loop voltage follower with output local Current-Current Feedback based on a level-shifted flipped voltage follower (LSFVF) to achieve high regulation and fast transient response. The inverting output buffer stage of the CFA together with Current-mirror-based driving of the power pass transistor results in high PSRR. The circuit does not require any internal compensation capacitor and is stable for a wide range of output load Currents 0-100 mA and a 1μF output capacitor. Post-layout simulation results for a 0.35μm CMOS process reveal that the maximum output voltage deviation of the proposed LDO for 0-100mA load transient with rise and fall times of 10 and 100ns is only 3mV, and the PSRR is smaller than -56dB over the entire load Current range.
R. Nandi - One of the best experts on this subject based on the ideXlab platform.
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a single resistor tunable grounded capacitor dual input differentiator
Circuits and Systems, 2015Co-Authors: Koushick Mathur, P. Venkateswaran, R. NandiAbstract:A new Current Feedback Amplifier (CFA) based dual-input differentiator (DID) design with grounded capacitor is presented; its time constant (τo) is independently tunable by a single resistor. The proposed circuit yields a true DID function with ideal CFA devices. Analysis with nonideal devices having parasitic capacitance (Cp) shows extremely low but finite phase error (θe); suitable design θe could be minimized significantly. The design is practically active-insensitive relative to port mismatch errors (e) of the active element. An allpass phase shifter circuit implementation is derived with slight modification of the differentiator. Satisfactory experimental results had been verified on typical wave processing and phase-selective filter design applications.
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Selective Filters and Sinusoidal Oscillators Using CFA Transimpedance Pole
Circuits Systems & Signal Processing, 2009Co-Authors: R. Nandi, T. K. Bandyopadhyay, S K SanyalAbstract:Using a single Current Feedback Amplifier (CFA) device, two new variable frequency sinusoidal RC oscillators are presented. The transadmittance pole of the device (AD-844) has been utilized in the design for generating sine wave signals covering a range of 1 MHz≤ f _0≤31 MHz. Under open-loop conditions, both circuits exhibit resonance characteristics at moderate Q -values (1≤ Q ≤9). These responses have been experimentally verified with hardware circuit implementation and PSPICE macromodel simulation.
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Single CFA-Based Integrator, Differentiator, Filter, and Sinusoid Oscillator
IEEE Transactions on Instrumentation and Measurement, 2009Co-Authors: R. Nandi, S K Sanyal, T. K. BandyopadhyayAbstract:A new multifunction configuration using a single Current Feedback Amplifier (CFA) and a few RC components is presented. The analysis for the various signal processing function realizability had been carried out by utilizing the internal parasitic and transimpedance elements of the CFA (AD-844 or 846) device. The circuit implements the functions of integrator/differentiator, high-selectivity (Q ges 20) filters, and sinusoid oscillator (Q rarr infin) on the same topology with the appropriate design. Adjustment of the time constant (T), filter quality (Q), and oscillation frequency (omegao) may be obtained with single-component variation at extended frequency ranges (1-30 MHz). All of the proposed functional performances had satisfactorily been verified with PSPICE macromodel simulation and by hardware circuit implementation.
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Current Mode Nonminimum-Phase Allpass Filters using a Current Feedback Amplifier
2006 International Conference on Electrical and Computer Engineering, 2006Co-Authors: R. Nandi, S K Sanyal, T. K. BandyopadhyayAbstract:The realization of nonminimum-phase allpass filters using a Current Feedback Amplifier (CFA) device is proposed. A simple circuit topology suitable for first and second order functions is presented. With nonideal CFA the pertinent expressions are slightly altered owing to finite port tracking errors (epsi) of the device. The modified design equations have been derived, and it is seen that the realizations are practically active-insensitive. Test results in support of theoretical analysis are presented.
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Lossless inductor using Current Feedback Amplifier
International Symposium on Signals Circuits and Systems 2005. ISSCS 2005., 2005Co-Authors: T. K. Bandyopadhyay, Rajendra Kumar Nagaria, S K Sanyal, R. NandiAbstract:A lossless grounded inductor simulation scheme using the Current Feedback Amplifier (CFA) device is proposed. The circuit configuration is a minimal $RC realisation that exhibits extremely low active sensitivity. The effects of the port tracking errors (/spl epsiv//sub t,v,t/) on the circuit parameters have been examined, and, subsequently compensation design equations have been derived. Tuning of this inductor by a capacitor across the driving point port yields a LC bandpass filter characteristics and self-oscillatory sinusoidal response (Q /spl rarr/ /spl infin/) which had been experimentally verified by hardware design and PSPICE macromodel simulation.
Jiun-wei Horng - One of the best experts on this subject based on the ideXlab platform.
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A Grounded Capacitor Differentiator Using Current Feedback Amplifier
Circuits and Systems, 2020Co-Authors: Jiun-wei Horng, Guang-ting HuangAbstract:A new non-inverting RC active differentiator network base on a Current Feedback Amplifier and using a grounded capacitor is described. Small time constant can be achieved by adjusting a single grounded resistor. Because the output impedance of the CFA is very low, the output terminal of the proposed circuit can be directly connected to the next stage. Experimental results that confirm theoretical analysis are presented.
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voltage Current mode multifunction filters using one Current Feedback Amplifier and grounded capacitors
Circuits and Systems, 2011Co-Authors: Jiun-wei Horng, Weishyang Huang, Dunyih YangAbstract:One configuration for realizing voltage-mode multifunction filters and another configuration for realizing Current-mode multifunction filters using Current Feedback Amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed Current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions; low active and passive sensitivities; employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.
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Voltage/Current-Mode Multifunction Filters Using One Current Feedback Amplifier and Grounded Capacitors
Circuits and Systems, 2011Co-Authors: Jiun-wei Horng, Weishyang Huang, Dunyih YangAbstract:One configuration for realizing voltage-mode multifunction filters and another configuration for realizing Current-mode multifunction filters using Current Feedback Amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed Current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions; low active and passive sensitivities; employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.
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Universal active voltage filter using single minus-type Current Feedback Amplifier
2008Co-Authors: Chun-ming Chang, Shu-hui Tu, Jiun-wei HorngAbstract:The realization of the second-order universal (low-pass, band-pass, high-pass, band-reject, and all-pass) activevoltage filter using a single minus-type Current Feedback Amplifier (CFA), two capacitors, and two resistosrs is proposed in this paper. The different choice of three voltage input signals determines the five generic filtering output signals. H-Spice simulations with 0.35µm process are used to validate the theoretical predictions of the filtering output signals, and show its low sensitivities and the sensitivity frequency responses.
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voltage mode multifunction filter using one Current Feedback Amplifier and one voltage follower
International Journal of Electronics, 2001Co-Authors: Jiun-wei HorngAbstract:A universal voltage-mode second-order filter with three inputs and one output employing one Current Feedback Amplifier, one voltage follower, two capacitors and two resistors is presented. It offers the following features: realization of allpass, notch, highpass, bandpass and lowpass signals from the same configuration, no requirements for component-matching conditions, orthogonal control of natural frequency and bandwidth, low active and passive sensitivities, minimum active and passive components and cascadability.
