19 documents found, page 1 of 2
A Tunable Gain and Bandwidth Low-Noise Amplifier with 1.44 NEF for EMG and EOG ...
Vieira, Rafael; Näf, Fabian; Martins, Ricardo; Horta, Nuno; Lourenço, N.; Póvoa, RicardoThis paper presents a low-noise inverter-based current-mode instrumentation amplifier with tunable gain and bandwidth for electromyogram (EMG) and electrooculogram (EOG) biopotential signals, targeting low input noise while maintaining low power consumption. The gain tuning method is based on pseudo-resistors, whereas the bandwidth is tunable due to a varactor system that is controlled by the same control volta...
Radiation-Hardened Bandgap Voltage and Current Reference for Space Applications...
Lourenço, N.; Passos, F.; Vieira, R.; Horta, N.; Guilherme, J.; Póvoa, R.This paper describes a radiation-hardened bandgap voltage reference (BGR) for space applications. The BGR has a second-order curvature compensation and can deliver a stable output voltage and current for N-type and P-type loads through internal resistors or, optionally, through an external precision resistor. The circuit includes three 8-bit trimming resistive ladders for post-fabrication calibration of the tem...
Architectural Design for Heartbeat Detection Circuits using Verilog-A Behaviora...
Vieira, R.; Passos, F.; Póvoa, R.; Martins, R.; Horta, N.; Guilherme, J.; Lourenço, N.This work presents a study of two analog frontend circuit architectures for heartbeat detection. Both circuits present an amplification block as the first stage, followed by a band-pass filter. In the first, the heartbeat detection is done using an adaptive threshold based on pulse-width, whereas the heartbeat detection in the second is done using a sample and hold to find the maximum and minimum peak of each b...
Sub- μW Tow-Thomas Based Biquad Filter with Improved Gain for Biomedical Applic...
Póvoa, R.; Arya, R.; Canelas, A.; Passos, F.; Martins, R.; Lourenço, N.; Horta, N.This paper presents an innovative topology of a gm-C Operational Transconductance Amplifier (OTA), with improved gain and energy-efficiency and its corresponding implementation inside a second order Tow-Thomas based filter configuration, for biomedical and healthcare applications. The proposed OTA architecture takes advantage of a current division technique, as well as the usage of a pair of cross-coupled volta...
A Folded Voltage-Combiners Biased Amplifier for Low Voltage and High Energy-Eff...
Póvoa, R.; Lourenço, N.; Martins, R.; Canelas, A.; Horta, N.; Goes, J.The topic of this brief is a ingle-stage amplifier biased by a doublet of voltage-combiners in a folded configuration, in order to be supplied by a power source of 1.2 V, maintaining proper dc biasing and voiding the need of any device stacking. The topology has been automatically designed, optimized, and laid out, from sizing to layout level, using a layout-aware approach provided by the AIDA framework, a stat...
Single-Stage Amplifier biased by Voltage-Combiners with Gain and Energy-Efficie...
Póvoa, R.; Lourenço, N.; Martins, R.; Canelas, A.; Horta, N.; Goes, J.This brief presents the design of a single-stage amplifier with enhanced gain and speed, without the need for using any cascode devices, positive feedback, or feed forward technique. Instead, two voltage-combiners replace the traditional tail current source, commonly employed to bias the differential pair. The resultant topology shows both additional dc gain and a gain bandwidth product enhancement. Simulation ...
Single Stage OTA biased by Voltage-Combiners with Enhanced Performance using Cu...
Póvoa, R.; Lourenço, N.; Martins, R.; Canelas, A.; Horta, N.; Goes, J.This brief presents an improved single-stage amplifier biased by voltage-combiners, through the proper usage of current starving. The topology designed and fabricated shows an enhancement of the low-frequency gain, an improvement in the establishing time due to enhanced gain-bandwidth product, and a high improvement of the energy efficiency. The circuit was optimized using AIDA-C, a state-of-the-art multi-objec...
Dynamic Voltage-Combiners Biased OTA for Low-Power High-Speed SC Circuits
Póvoa, R.; Canelas, A.; Martins, R.; Lourenço, N.; Horta, N.; Goes, J.his paper presents the design of a fully-dynamic voltage-combiners biased CMOS operational transconductance amplifier, for low-power high-speed analog-to-digital converters and high-performance switched-capacitor filters, using the UMC 130nm node. The biasing is controlled by switched-capacitors and simulation results of an optimized solution using AIDA-C, a state-of-the-art multi-objective multi-constraint IC ...
New Mapping Strategies for Pre-Optimized Inductor Sets in Bottom-Up RF IC Sizin...
Lourenço, N.; Martins, R.; Póvoa, R.; Canelas, A.; Horta, N.; Passos, F.; Castro López, R.; Roca, E.; Fernández, F.This paper presents new indexing and mutation operators, in the context of bottom-up hierarchical multi-objective optimization of radio frequency integrated circuits, for pre-optimized sets of solutions from the hierarchical sub-levels when moving up in hierarchy. Two ideas, one based on a Voronoi decomposition and another based on the nearest neighborhood, are explored, where, and unlike previous approaches th...
Systematic Design of a Voltage Controlled Oscillator using a Layout-Aware Approach
Passos, F.; Castro Lópes, R.; Roca, E.; Fernándes, F.; Martins, R.; Lourenço, N.; Póvoa, R.; Canelas, A.; Horta, N.This paper focuses on the systematic design of voltage controlled oscillators (VCO), a commonly used radiofrequency (RF) electronic circuit. RF circuits are among the most difficult analog circuits to design due to its trade-offs and high operation frequencies. At such operation frequencies, layout parasitics and accurate passive component characterization become of upmost importance, causing re-design iteratio...