A method for growth of highly (100)-oriented aluminum nitride (AlN) thin films on (100) Si substr... more A method for growth of highly (100)-oriented aluminum nitride (AlN) thin films on (100) Si substrate, in poor vacuum systems, by radio frequency magnetron sputtering was developed. This method allows prediction for near ideal deposition conditions in which high quality films with good stoichiometry Al/N (≈1:1) and low oxygen concentration (< 10%) are produced. During the depositions, the substrate was fed by floating potential. The temperature, the nitrogen flow, RF power and sputtering pressure were fixed, whereas the target-substrate distance and the deposition time were varied. Rutherford backscattering spectroscopy (RBS) measurements estimated film thicknesses of 170 nm, 255 nm, and 480 nm and the amount of oxygen incorporated of 43.32%, 29.80%, and 24.67%, respectively. XRD analysis revealed that films grown with substrate placed near the region of the cathodic sheath are amorphous. However, the other three samples exhibited good crystallinity and orientation (100). Surface properties of the films have been also examined by Fourier transform infrared and Raman spectroscopy. Overall, the characteristics of the obtained highly (100)-oriented AlN films evidence their potential to fabricate surface acoustic wave (SAW) sensing devices.
A low-voltage (⩽3 V) low-power CMOS voltage-to-current converter is introduced which has an a... more A low-voltage (⩽3 V) low-power CMOS voltage-to-current converter is introduced which has an almost rail-to-rail differential-input swing (±1.5 V) with a low signal-distortion (⩽1%) with a minimum supply voltage of 2 V. The proposed circuit uses class-AB linearization to achieve full-input-swing in the saturation region. In a 1.2 μm n-well CMOS process, the 3 dB frequency of the V-I converter
Abstract A universal exponential function generator is introduced which is implemented by low-vol... more Abstract A universal exponential function generator is introduced which is implemented by low-voltage (&amp;amp;amp;amp;amp;amp;amp;amp;les; 3 V) low-power CMOS widely-linear-input voltage-to-current converters. The Taylor&amp;amp;amp;amp;amp;amp;amp;#x27;s series expansion is used for the exponential function approach. The ...
A micropower CMOS voltage-to-current converter is introduced which has a widely linear differenti... more A micropower CMOS voltage-to-current converter is introduced which has a widely linear differential-input swing with a low signal-distortion with a minimum supply voltage of 1.2 V. This proposed circuit can achieve an almost rail-to-rail differential-input swing with at least 1.5 V supply-voltage. The proposed circuit uses class-AB linearisation to achieve widely linear input-swing in the saturation region. In a 1.2
This paper presents a dynamic reconfiguration method for electrical connections in a Series-Paral... more This paper presents a dynamic reconfiguration method for electrical connections in a Series-Parallel connected photovoltaic array under partial shading conditions. It is desirable to extract the maximum energy from the array, but it does not occur in situations where the modules have different points of operation caused by shading. The proposed method is then characterized by the maintenance of the PV array dimensions, that is; no module is removed or added to the array. Furthermore, the control algorithm is based on the Rough Sets Theory, which allows the fast and efficient implementation of a control system, comprising rules that identify the system optimal configuration.
Asia-Pacific Conference on Circuits and Systems, 2002
This work describes a new topology for CMOS sample-and-hold circuits, in low voltage, with self-c... more This work describes a new topology for CMOS sample-and-hold circuits, in low voltage, with self-correction of the offset voltage caused by mismatches in the differential input pair of the operational amplifier. The charge injection of the NMOS switches is an important factor and it is minimized in this topology. The results were obtained using the ACCUSIM II simulator on the
9th International Conference on Electronics, Circuits and Systems, 2002
This work describes a new topology for CMOS sample-and-hold circuits in low voltage with self-cor... more This work describes a new topology for CMOS sample-and-hold circuits in low voltage with self-correction of the offset voltage caused by mismatches in the differential input pair of the operational amplifier. The charge injection of the NMOS switches, although not properly modeled by the simulators, is an important factor and it is minimized in this topology. The results were obtained
1998 Midwest Symposium on Circuits and Systems (Cat. No. 98CB36268), 1999
Abstract A universal exponential function generator is introduced which is implemented by low-vol... more Abstract A universal exponential function generator is introduced which is implemented by low-voltage (&amp;amp;amp;amp;amp;amp;amp;amp;les; 3 V) low-power CMOS widely-linear-input voltage-to-current converters. The Taylor&amp;amp;amp;amp;amp;amp;amp;#x27;s series expansion is used for the exponential function approach. The ...
Proceedings. XI Brazilian Symposium on Integrated Circuit Design (Cat. No.98EX216), 1998
This paper describes how to implement a CMOS expo-nential function circuit, which can be used for... more This paper describes how to implement a CMOS expo-nential function circuit, which can be used for Auto-matic Gain Control AGC and Variable Gain Ampli-fiers VGA . The proposed exponential function circuit is based on Taylor&amp;amp;amp;amp;amp;amp;amp;#x27;s series expansion, and it has been im-plemented ...
1998 Midwest Symposium on Circuits and Systems (Cat. No. 98CB36268), 1999
Abstract A micropower CMOS voltage-to-current converter is introduced which has a widely linear d... more Abstract A micropower CMOS voltage-to-current converter is introduced which has a widely linear differential-input swing with a low signal-distortion with a minimum supply voltage of 1.2 V. This proposed circuit can achieve an almost rail-to-rail differential-input swing with ...
2012 VIII Southern Conference on Programmable Logic, 2012
ABSTRACT This paper presents the implementation and integration the AES 128 data encryption IP an... more ABSTRACT This paper presents the implementation and integration the AES 128 data encryption IP and the I2C serial communication interface IP, into the IP of the M8051 microcontroller. We detail each block and validate them though testbench simulation. We performed functionality testing in FPGA to verify the correct functioning of the IPs and their integration.
ABSTRACT This paper describes a voltage reference circuit based on composite transistors and oper... more ABSTRACT This paper describes a voltage reference circuit based on composite transistors and operating in weak inversion mode. The voltage reference was fixed in 100mV and the supply voltage can be as low as 0.8V. The weak inversion allows small current too leading the total power in the nW range. Simulation results points to a deviation (3σ and process corner) less than ±1%. The reference is indicated to be used in biomedical applications specially those that use implanted devices. In these cases the temperature impact is minimized since the human body has an effective biological system to keep it constant at about 37°C.
2003 5th International Conference on ASIC Proceedings (IEEE Cat No 03TH8690) ICASIC-03, 2003
This work describes the silicon implementation of a new sample-and-hold circuit topology. The mai... more This work describes the silicon implementation of a new sample-and-hold circuit topology. The main feature of the circuit is its auto-zero capability. The auto-zero corrects the offset voltage generated by the transistor mismatch in the differential pair and the charge injected by the NMOS switches in the sampling capacitor. The circuit was implemented in 0.8 μm CMOS process from AMS.
Analog Integrated Circuits and Signal Processing, 2014
ABSTRACT This paper presents a 0.25-V supplied bulk-driven symmetrical OTA implemented in 130-nm ... more ABSTRACT This paper presents a 0.25-V supplied bulk-driven symmetrical OTA implemented in 130-nm CMOS process. By operating in weak inversion, and using a distributed layout approach, the OTA can benefit from the voltage reduction and high linearity enabled by halo-implanted transistors. The proposed circuit consumes only 10-nW, features a low transconductance of 22-nS, and a total harmonic distortion of 0.53 % for a 100-mVpp input voltage, thus making it suitable for low-frequency and low-power \(G_m\)-C applications.
2011 18th IEEE International Conference on Electronics, Circuits, and Systems, 2011
In this paper, we present a signal processing method capable of detecting angina in electrocardio... more In this paper, we present a signal processing method capable of detecting angina in electrocardiograms, that was implemented in FPGA. The adopted procedure is based on fuzzy clustering to reduce the amount of data sampling and correlation to compare with samples from a previously established database. By using the correlation method on the samples, it is possible to establish an
A method for growth of highly (100)-oriented aluminum nitride (AlN) thin films on (100) Si substr... more A method for growth of highly (100)-oriented aluminum nitride (AlN) thin films on (100) Si substrate, in poor vacuum systems, by radio frequency magnetron sputtering was developed. This method allows prediction for near ideal deposition conditions in which high quality films with good stoichiometry Al/N (≈1:1) and low oxygen concentration (< 10%) are produced. During the depositions, the substrate was fed by floating potential. The temperature, the nitrogen flow, RF power and sputtering pressure were fixed, whereas the target-substrate distance and the deposition time were varied. Rutherford backscattering spectroscopy (RBS) measurements estimated film thicknesses of 170 nm, 255 nm, and 480 nm and the amount of oxygen incorporated of 43.32%, 29.80%, and 24.67%, respectively. XRD analysis revealed that films grown with substrate placed near the region of the cathodic sheath are amorphous. However, the other three samples exhibited good crystallinity and orientation (100). Surface properties of the films have been also examined by Fourier transform infrared and Raman spectroscopy. Overall, the characteristics of the obtained highly (100)-oriented AlN films evidence their potential to fabricate surface acoustic wave (SAW) sensing devices.
A low-voltage (⩽3 V) low-power CMOS voltage-to-current converter is introduced which has an a... more A low-voltage (⩽3 V) low-power CMOS voltage-to-current converter is introduced which has an almost rail-to-rail differential-input swing (±1.5 V) with a low signal-distortion (⩽1%) with a minimum supply voltage of 2 V. The proposed circuit uses class-AB linearization to achieve full-input-swing in the saturation region. In a 1.2 μm n-well CMOS process, the 3 dB frequency of the V-I converter
Abstract A universal exponential function generator is introduced which is implemented by low-vol... more Abstract A universal exponential function generator is introduced which is implemented by low-voltage (&amp;amp;amp;amp;amp;amp;amp;amp;les; 3 V) low-power CMOS widely-linear-input voltage-to-current converters. The Taylor&amp;amp;amp;amp;amp;amp;amp;#x27;s series expansion is used for the exponential function approach. The ...
A micropower CMOS voltage-to-current converter is introduced which has a widely linear differenti... more A micropower CMOS voltage-to-current converter is introduced which has a widely linear differential-input swing with a low signal-distortion with a minimum supply voltage of 1.2 V. This proposed circuit can achieve an almost rail-to-rail differential-input swing with at least 1.5 V supply-voltage. The proposed circuit uses class-AB linearisation to achieve widely linear input-swing in the saturation region. In a 1.2
This paper presents a dynamic reconfiguration method for electrical connections in a Series-Paral... more This paper presents a dynamic reconfiguration method for electrical connections in a Series-Parallel connected photovoltaic array under partial shading conditions. It is desirable to extract the maximum energy from the array, but it does not occur in situations where the modules have different points of operation caused by shading. The proposed method is then characterized by the maintenance of the PV array dimensions, that is; no module is removed or added to the array. Furthermore, the control algorithm is based on the Rough Sets Theory, which allows the fast and efficient implementation of a control system, comprising rules that identify the system optimal configuration.
Asia-Pacific Conference on Circuits and Systems, 2002
This work describes a new topology for CMOS sample-and-hold circuits, in low voltage, with self-c... more This work describes a new topology for CMOS sample-and-hold circuits, in low voltage, with self-correction of the offset voltage caused by mismatches in the differential input pair of the operational amplifier. The charge injection of the NMOS switches is an important factor and it is minimized in this topology. The results were obtained using the ACCUSIM II simulator on the
9th International Conference on Electronics, Circuits and Systems, 2002
This work describes a new topology for CMOS sample-and-hold circuits in low voltage with self-cor... more This work describes a new topology for CMOS sample-and-hold circuits in low voltage with self-correction of the offset voltage caused by mismatches in the differential input pair of the operational amplifier. The charge injection of the NMOS switches, although not properly modeled by the simulators, is an important factor and it is minimized in this topology. The results were obtained
1998 Midwest Symposium on Circuits and Systems (Cat. No. 98CB36268), 1999
Abstract A universal exponential function generator is introduced which is implemented by low-vol... more Abstract A universal exponential function generator is introduced which is implemented by low-voltage (&amp;amp;amp;amp;amp;amp;amp;amp;les; 3 V) low-power CMOS widely-linear-input voltage-to-current converters. The Taylor&amp;amp;amp;amp;amp;amp;amp;#x27;s series expansion is used for the exponential function approach. The ...
Proceedings. XI Brazilian Symposium on Integrated Circuit Design (Cat. No.98EX216), 1998
This paper describes how to implement a CMOS expo-nential function circuit, which can be used for... more This paper describes how to implement a CMOS expo-nential function circuit, which can be used for Auto-matic Gain Control AGC and Variable Gain Ampli-fiers VGA . The proposed exponential function circuit is based on Taylor&amp;amp;amp;amp;amp;amp;amp;#x27;s series expansion, and it has been im-plemented ...
1998 Midwest Symposium on Circuits and Systems (Cat. No. 98CB36268), 1999
Abstract A micropower CMOS voltage-to-current converter is introduced which has a widely linear d... more Abstract A micropower CMOS voltage-to-current converter is introduced which has a widely linear differential-input swing with a low signal-distortion with a minimum supply voltage of 1.2 V. This proposed circuit can achieve an almost rail-to-rail differential-input swing with ...
2012 VIII Southern Conference on Programmable Logic, 2012
ABSTRACT This paper presents the implementation and integration the AES 128 data encryption IP an... more ABSTRACT This paper presents the implementation and integration the AES 128 data encryption IP and the I2C serial communication interface IP, into the IP of the M8051 microcontroller. We detail each block and validate them though testbench simulation. We performed functionality testing in FPGA to verify the correct functioning of the IPs and their integration.
ABSTRACT This paper describes a voltage reference circuit based on composite transistors and oper... more ABSTRACT This paper describes a voltage reference circuit based on composite transistors and operating in weak inversion mode. The voltage reference was fixed in 100mV and the supply voltage can be as low as 0.8V. The weak inversion allows small current too leading the total power in the nW range. Simulation results points to a deviation (3σ and process corner) less than ±1%. The reference is indicated to be used in biomedical applications specially those that use implanted devices. In these cases the temperature impact is minimized since the human body has an effective biological system to keep it constant at about 37°C.
2003 5th International Conference on ASIC Proceedings (IEEE Cat No 03TH8690) ICASIC-03, 2003
This work describes the silicon implementation of a new sample-and-hold circuit topology. The mai... more This work describes the silicon implementation of a new sample-and-hold circuit topology. The main feature of the circuit is its auto-zero capability. The auto-zero corrects the offset voltage generated by the transistor mismatch in the differential pair and the charge injected by the NMOS switches in the sampling capacitor. The circuit was implemented in 0.8 μm CMOS process from AMS.
Analog Integrated Circuits and Signal Processing, 2014
ABSTRACT This paper presents a 0.25-V supplied bulk-driven symmetrical OTA implemented in 130-nm ... more ABSTRACT This paper presents a 0.25-V supplied bulk-driven symmetrical OTA implemented in 130-nm CMOS process. By operating in weak inversion, and using a distributed layout approach, the OTA can benefit from the voltage reduction and high linearity enabled by halo-implanted transistors. The proposed circuit consumes only 10-nW, features a low transconductance of 22-nS, and a total harmonic distortion of 0.53 % for a 100-mVpp input voltage, thus making it suitable for low-frequency and low-power \(G_m\)-C applications.
2011 18th IEEE International Conference on Electronics, Circuits, and Systems, 2011
In this paper, we present a signal processing method capable of detecting angina in electrocardio... more In this paper, we present a signal processing method capable of detecting angina in electrocardiograms, that was implemented in FPGA. The adopted procedure is based on fuzzy clustering to reduce the amount of data sampling and correlation to compare with samples from a previously established database. By using the correlation method on the samples, it is possible to establish an
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