The Experts below are selected from a list of 24477 Experts worldwide ranked by ideXlab platform
Kofi A A Makinwa - One of the best experts on this subject based on the ideXlab platform.
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Interface Electronics for a cmos electrothermal frequency locked loop
IEEE Journal of Solid-state Circuits, 2008Co-Authors: Cheng Zhang, Kofi A A MakinwaAbstract:This paper describes a new implementation of a CMOS electrothermal frequency-locked-loop (FLL), whose output frequency is determined by the temperature-dependent phase shift of an electrothermal filter (ETF). The FLL maintains a constant phase shift in the ETF, and as a result drives it with a signal whose frequency is a well-defined function of temperature. Compared to a previous implementation, the FLL described here has significantly more loop gain, less electrical phase-spread, and is more suitable for full integration. Measurements on 16 samples (from one batch) show that the temperature dependence of the FLL's output frequency agrees very well with the known thermal properties of bulk silicon. The untrimmed spread of this frequency is less than plusmn0.45% (3sigma) from -40degC to 100degC, which corresponds to a temperature-sensing inaccuracy of less than plusmn0.7degC (3sigma).
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Interface Electronics for a cmos electrothermal frequency locked loop
European Solid-State Circuits Conference, 2007Co-Authors: Cheng Zhang, Kofi A A MakinwaAbstract:A new architecture for a CMOS electrothermal frequency-locked-loop (FLL) is presented. Unlike previous work, it does not require the use of off-chip capacitors. The FLL's output frequency is determined by the well-defined thermal diffusivity of bulk silicon. Measurements show that the spread in the FLL's output frequency corresponds to an untrimmed inaccuracy of less than plusmn0.7degC (3sigma) over the temperature range from -40degC to 100degC.
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a wind sensor Interface using thermal sigma delta modulation techniques
Sensors and Actuators A-physical, 2001Co-Authors: Kofi A A Makinwa, J H HuijsingAbstract:An electronic Interface for an integrated wind-sensor is described. The sensor is based on a heated silicon chip that is cooled asymmetrically by the wind. The Interface maintains the entire chip at a constant temperature above that of the airflow by dynamically regulating the power dissipated in four on-chip resistors used as heaters. The voltages required to drive these resistors are bit-streams generated using thermal Sigma Delta (ΣΔ) modulation techniques. These bit-streams can be directly connected to an external microprocessor, where they are decimated to obtain digital words representing the power dissipated in each heater. An explicit analog-to-digital (A/D) converter in the Interface Electronics is, thus, not required. It is shown that wind speed and direction may be accurately determined from the measured power dissipated in the heaters.
Haluk Külah - One of the best experts on this subject based on the ideXlab platform.
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a triple hybrid micropower generator with simultaneous multi mode energy harvesting
Smart Materials and Structures, 2018Co-Authors: Hasan Ulusan, Salar Chamanian, W P M R Pathirana, Ali Muhtaroglu, Özge Zorlu, Haluk KülahAbstract:This study presents a triple hybrid energy harvesting system that combines harvested power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters into a single DC supply. A power management circuit is designed and implemented in 180 nm standard CMOS technology based on the distinct requirements of each harvester, and is terminated with a Schottky diode to avoid reverse current flow. The system topology hence supports simultaneous power generation and delivery from low and high frequency vibrations as well as temperature differences in the environment. The ultra-low DC voltage harvested from TE generator is boosted with a cross-coupled charge-pump driven by an LC oscillator with fully-integrated center-tapped differential inductors. The EM harvester output was rectified with a self-powered and low drop-out AC/DC doubler circuit. The PZT Interface Electronics benefits from peak-to-peak cycle of the harvested voltage through a negative voltage converter followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The hybrid system was tested with a wearable in-house EM energy harvester placed wrist of a jogger, a commercial low volume PZT harvester, and DC supply as the TE generator output. The system generates more than 1.2 V output for load resistances higher than 50 kΩ, which corresponds to 24 μW to power wearable sensors. Simultaneous multi-mode operation achieves higher voltage and power compared to stand-alone harvesting circuits, and generates up to 110 μW of output power. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.
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triple hybrid energy harvesting Interface Electronics
Journal of Physics: Conference Series, 2016Co-Authors: Hasan Ulusan, Salar Chamanian, Ali Muhtaroglu, Özge Zorlu, W M P R Pathirana, Haluk KülahAbstract:This study presents a novel triple hybrid system that combines simultaneously generated power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters for a relatively high power supply capability. In the proposed solution each harvesting source utilizes a distinct power management circuit that generates a DC voltage suitable for combining the three parallel supplies. The circuits are designed and implemented in 180 nm standard CMOS technology, and are terminated with a schottky diode to avoid reverse current flow. The harvested AC signal from the EM harvester is rectified with a self-powered AC-DC doubler, which utilizes active diode structures to minimize the forward- bias voltage drop. The PZT Interface Electronics utilizes a negative voltage converter as the first stage, followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The ultra-low voltage DC power harvested by the TE generator is stepped up through a charge-pump driven by an LC oscillator with fully- integrated center-tapped differential inductors. Test results indicate that hybrid energy harvesting circuit provides more than 1 V output for load resistances higher than 100 kΩ (10 μW) where the stand-alone harvesting circuits are not able to reach 1 V output. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.
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an efficient integrated Interface Electronics for electromagnetic energy harvesting from low voltage sources
International Conference on Solid-State Sensors Actuators and Microsystems, 2013Co-Authors: Hasan Ulusan, Ali Muhtaroglu, Özge Zorlu, Kaveh Gharehbaghi, Haluk KülahAbstract:This paper presents a fully-integrated self-powered Interface circuit for efficient rectification of the signals generated by vibration based low-voltage electromagnetic (EM) energy harvesters. The circuit utilizes an improved AC/DC doubler structure with active diodes to minimize the forward bias voltage drop for enhancing the rectifier efficiency. The comparators in the active diodes are powered internally by another passive AC/DC doubler with diode connected transistors. The performance is maximized through custom-designed comparators for each of the positive and negative terminals of the dual rail output. Measurement results show that the system is capable of driving 40 μA load at 0.61 V, with 67% power conversion efficiency, when operated together with an inhouse EM harvester subjected to vibrations at 10 Hz, 2.5 mm peak-to-peak displacement with 0.5 g acceleration. The circuit is able to rectify AC inputs with peak amplitude as low as 100 mV.
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a vibration based electromagnetic energy harvester system with highly efficient Interface Electronics
International Conference on Solid-State Sensors Actuators and Microsystems, 2011Co-Authors: Arian Rahimi, Ali Muhtaroglu, Özge Zorlu, Haluk KülahAbstract:This paper presents a vibration-based electromagnetic (EM) energy harvester system utilizing novel and highly efficient Interface Electronics. The energy harvesting module up-converts the environmental low frequency vibrations for increased AC power output. The Interface circuit employs a boot-strap technique to reduce the threshold voltage of the rectifiers further increasing the power conversion efficiency of the overall system. The complete system, composed of an energy harvester module, and a compact 0.35 µm CMOS IC, was fully validated. It is capable of powering a 1.5V, 15µA load with 65% conversion efficiency, and 5% ripple, at an external vibration frequency of 10Hz. The recorded efficiency is the highest achieved value for vibration-based EM energy harvesters with passive rectification to the best of our knowledge.
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a compact electromagnetic vibration harvesting system with high performance Interface Electronics
Procedia Engineering, 2011Co-Authors: Arian Rahimi, Ali Muhtaroglu, Özge Zorlu, Haluk KülahAbstract:Abstract A compact vibration-based electromagnetic (EM) energy harvesting system utilizing high performance Interface Electronics, has been presented. The energy harvester module consists of an AA-battery sized cylinder tube with an external coil winding, a fixed magnet at the bottom of the tube, and a free magnet inside. The transducer is able to operate at low external vibration frequencies between 9.5 and 12 Hz. The generated AC voltage is converted to DC using a custom rectifier circuit that utilizes a gate cross coupled (GCC) input stage. This decreases the effective threshold voltage of the utilized diodes, while increasing the DC output power delivered to the load. The autonomous system, composed of an EM energy harvester module and a 0.35 μm CMOS IC, delivers 11.6 μW power to a 41 μA load at an external vibration frequency of 12 Hz. The volume of the total system is 4.5 cm3, and the overall system power density is 2.6 μW/cm3.
Cheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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Interface Electronics for a cmos electrothermal frequency locked loop
IEEE Journal of Solid-state Circuits, 2008Co-Authors: Cheng Zhang, Kofi A A MakinwaAbstract:This paper describes a new implementation of a CMOS electrothermal frequency-locked-loop (FLL), whose output frequency is determined by the temperature-dependent phase shift of an electrothermal filter (ETF). The FLL maintains a constant phase shift in the ETF, and as a result drives it with a signal whose frequency is a well-defined function of temperature. Compared to a previous implementation, the FLL described here has significantly more loop gain, less electrical phase-spread, and is more suitable for full integration. Measurements on 16 samples (from one batch) show that the temperature dependence of the FLL's output frequency agrees very well with the known thermal properties of bulk silicon. The untrimmed spread of this frequency is less than plusmn0.45% (3sigma) from -40degC to 100degC, which corresponds to a temperature-sensing inaccuracy of less than plusmn0.7degC (3sigma).
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Interface Electronics for a cmos electrothermal frequency locked loop
European Solid-State Circuits Conference, 2007Co-Authors: Cheng Zhang, Kofi A A MakinwaAbstract:A new architecture for a CMOS electrothermal frequency-locked-loop (FLL) is presented. Unlike previous work, it does not require the use of off-chip capacitors. The FLL's output frequency is determined by the well-defined thermal diffusivity of bulk silicon. Measurements show that the spread in the FLL's output frequency corresponds to an untrimmed inaccuracy of less than plusmn0.7degC (3sigma) over the temperature range from -40degC to 100degC.
Maurizio Valle - One of the best experts on this subject based on the ideXlab platform.
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fpga based tactile sensory feedback system with optical fiber data communication link for prosthetic applications
International Conference on Electronics Circuits and Systems, 2019Co-Authors: G Di Patrizio Stanchieri, Maurizio Valle, Ali Ibrahim, M Saleh, M Sciulli, A De Marcellis, M Faccio, Elia PalangeAbstract:Tactile sensory feedback systems could enable the prosthetic system to convey touch information to the amputee. Employing sensor arrays with a high number of sensors gives high-resolution tactile information but imposes challenges on the embedded Electronics in processing and transmitting a large number of tactile data to the prosthetic user. This work proposes the design of a FPGA-based approach for tactile sensory feedback systems that employs an optical fiber data communication link for prosthetic applications. The system consists of an Interface Electronics to manage the data acquisition from the tactile sensor array, a digital coding unit, an optical fiber-based communication link, a digital decoding unit and a further Interface Electronics to communicate with external apparatus. The data acquisition process followed by a UWB-based optical modulation allows for the transmission of pulsed coded tactile data through the optical fiber to a final user by means of, for example, an electrotactile stimulator combined with flexible electrodes. The transmitter and receiver systems have been implemented on two different FPGA boards with the optical communication channel connecting the two boards. The designed system functionality was demonstrated by employing an experimental setup where sequence of sensor data, emulating an array of 32 sensors sampled at 2kHz, were employed to verify the correctness of the data transmission at 100Mbps data rate through the optical fiber. Experimental results validated the functionality of the proposed design and demonstrated that the optical communication link highly improves the robustness to electromagnetic disturbances, the transmission data rate as well as the power consumption.
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Interface Electronics for tactile sensors based on piezoelectric polymers
IEEE Sensors Journal, 2017Co-Authors: Luigi Pinna, Ali Ibrahim, Maurizio ValleAbstract:In this paper, we propose a novel design approach for the Interface Electronics of piezoelectric polymer tactile sensing systems. An Interface Electronics prototype based on commercial off-the-shelf (COTS) components having the same operating principle as the proposed approach has been fabricated. The system has been validated by using an experimental setup, where electrical and electromechanical characterization are carried out. The Interface Electronics measures charge of about 0.15 pC for applied forces as low as 12.5 mN at the working frequency of 27 Hz. The experimental average sensitivity of the system is 0.6 pC/kPa in the frequency range from 10 to 250 Hz. Long term goal is to miniaturize the Interface Electronics for the development of embedded tactile systems in prosthetic and robotic applications.
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posfet touch sensing transducers Interface Electronics design methodology based on the transconductance to drain current efficiency gm id
Sensors and Actuators A-physical, 2013Co-Authors: L Arboni, Maurizio ValleAbstract:Abstract This paper deals with tactile sensing systems based on a piezoelectric polymer poly(vinylidene fluoride-trifluoroethylene) film on the gate area of a MOS (Metal Oxide Semiconductor) transistor: Piezoelectric Oxide Semiconductor Field Effect Transistor, POSFET. More specifically, we present the design and analysis of the Interface electronic circuit between the touch sensor transducer and the signal conditioning circuit stage. The circuit configuration is based on a NMOS transistor in common-drain and floating gate bias configuration. Such configuration enhances and complements the transducer's response. However, the circuit Interface design suffers of the very difficult analytical tractability. For this reason, a graphical methodology, intended to give a criterion for achieving the selection of the most appropriate bias resistance value has been developed. The methodology utilizes the Advanced Compact MOSFET (ACM) model and the gm characteristic as function of the NMOS transistor drain current ID. A design space map shows confidence regions where the specifications such as touch sensing device gain, current consumption and source resistance value are met. The design methodology enables to push the performance of the POSFET by selecting the most appropriate bias resistance value and it reduces time-consuming iterations which are normally required. As a proof of concept of the proposed methodology, measurements as well as a design example are presented.
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Interface Electronics for tactile sensing arrays
2011 18th IEEE International Conference on Electronics Circuits and Systems, 2011Co-Authors: Luigi Pinna, Giorgio Carlini, Lucia Seminara, Maurizio ValleAbstract:This paper presents the Interface Electronics design and implementation of a tactile sensing system for humanoid robot applications. The tactile system is designed to cover the human tactile sensing bandwidth ranging from 1Hz to 1kHz and to operate on a wide range of input forces/pressures. Some Interface Electronics prototypes have been designed and fabricated. The paper reports the experimental results and the validation of the proposed implementation. We report also results of the electro-mechanical response of the tactile sensing system (i.e. tactile sensing array + Interface Electronics) to external mechanical stimuli. The current implementation is a first step towards dedicated IC integration.
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Interface Electronics design for posfet devices based tactile sensing systems
Robot and Human Interactive Communication, 2010Co-Authors: Leonardo Barboni, Ravinder Dahiya, Giorigio Metta, Maurizio ValleAbstract:This work presents the development of novel POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) devices based tactile sensing system. The tactile sensing system, primarily developed for the robotic applications, consists of 5×5 POSFET touch sensing array and the associated read out and data acquisition system. The POSFET touch sensing devices are obtained by spin coating piezoelectric polymer P(VDF-TrFE), poly(vinylidene fluoride - trifluoroethylene), film on the gate area of MOS (Metal Oxide Semiconductor) devices and polarizing the film in situ. To detect contact events, the taxels utilize the contact forces induced change in the polarization level (and hence change in the induced channel current) of piezoelectric polymer. Both, individual taxels and the array are designed to match spatio-temporal performance of the human fingertips. The data acquisition system is implemented with off-the-shelf electronic components and its design takes into account both the application related requirements as well as the constraints posed by existing hardware on the humanoid robot ‘iCub’. The biasing scheme for using POSFET devices and the problems thereof are also been discussed.
Hasan Ulusan - One of the best experts on this subject based on the ideXlab platform.
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a triple hybrid micropower generator with simultaneous multi mode energy harvesting
Smart Materials and Structures, 2018Co-Authors: Hasan Ulusan, Salar Chamanian, W P M R Pathirana, Ali Muhtaroglu, Özge Zorlu, Haluk KülahAbstract:This study presents a triple hybrid energy harvesting system that combines harvested power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters into a single DC supply. A power management circuit is designed and implemented in 180 nm standard CMOS technology based on the distinct requirements of each harvester, and is terminated with a Schottky diode to avoid reverse current flow. The system topology hence supports simultaneous power generation and delivery from low and high frequency vibrations as well as temperature differences in the environment. The ultra-low DC voltage harvested from TE generator is boosted with a cross-coupled charge-pump driven by an LC oscillator with fully-integrated center-tapped differential inductors. The EM harvester output was rectified with a self-powered and low drop-out AC/DC doubler circuit. The PZT Interface Electronics benefits from peak-to-peak cycle of the harvested voltage through a negative voltage converter followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The hybrid system was tested with a wearable in-house EM energy harvester placed wrist of a jogger, a commercial low volume PZT harvester, and DC supply as the TE generator output. The system generates more than 1.2 V output for load resistances higher than 50 kΩ, which corresponds to 24 μW to power wearable sensors. Simultaneous multi-mode operation achieves higher voltage and power compared to stand-alone harvesting circuits, and generates up to 110 μW of output power. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.
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triple hybrid energy harvesting Interface Electronics
Journal of Physics: Conference Series, 2016Co-Authors: Hasan Ulusan, Salar Chamanian, Ali Muhtaroglu, Özge Zorlu, W M P R Pathirana, Haluk KülahAbstract:This study presents a novel triple hybrid system that combines simultaneously generated power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters for a relatively high power supply capability. In the proposed solution each harvesting source utilizes a distinct power management circuit that generates a DC voltage suitable for combining the three parallel supplies. The circuits are designed and implemented in 180 nm standard CMOS technology, and are terminated with a schottky diode to avoid reverse current flow. The harvested AC signal from the EM harvester is rectified with a self-powered AC-DC doubler, which utilizes active diode structures to minimize the forward- bias voltage drop. The PZT Interface Electronics utilizes a negative voltage converter as the first stage, followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The ultra-low voltage DC power harvested by the TE generator is stepped up through a charge-pump driven by an LC oscillator with fully- integrated center-tapped differential inductors. Test results indicate that hybrid energy harvesting circuit provides more than 1 V output for load resistances higher than 100 kΩ (10 μW) where the stand-alone harvesting circuits are not able to reach 1 V output. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.
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an efficient integrated Interface Electronics for electromagnetic energy harvesting from low voltage sources
International Conference on Solid-State Sensors Actuators and Microsystems, 2013Co-Authors: Hasan Ulusan, Ali Muhtaroglu, Özge Zorlu, Kaveh Gharehbaghi, Haluk KülahAbstract:This paper presents a fully-integrated self-powered Interface circuit for efficient rectification of the signals generated by vibration based low-voltage electromagnetic (EM) energy harvesters. The circuit utilizes an improved AC/DC doubler structure with active diodes to minimize the forward bias voltage drop for enhancing the rectifier efficiency. The comparators in the active diodes are powered internally by another passive AC/DC doubler with diode connected transistors. The performance is maximized through custom-designed comparators for each of the positive and negative terminals of the dual rail output. Measurement results show that the system is capable of driving 40 μA load at 0.61 V, with 67% power conversion efficiency, when operated together with an inhouse EM harvester subjected to vibrations at 10 Hz, 2.5 mm peak-to-peak displacement with 0.5 g acceleration. The circuit is able to rectify AC inputs with peak amplitude as low as 100 mV.