• Journal of Korea Society of Industrial Information Systems
• /
• v.18 no.5
• /
• pp.39-44
• /
• 2013

In this paper, a Relaxation Oscillator with temperature compensation using BGR and ADC is presented. The current to determine the frequency of Relaxation Oscillator can be controlled. By adjusting the current according to the temperature using the code that is output from the ADC and BGR, was to compensate the output frequency of the temperature. It is fabricated in a 0.35 ${\mu}m$ CMOS process with an active area of $240{\mu}m{\times}210{\mu}m$. Current consumption is 600 ${\mu}A$ from a 5 V and the rate of change of the output frequency with temperature shows about ${\pm}1%$.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.4
• /
• pp.538-542
• /
• 2018

In order to generate a clock source with low cost and high performance in system on chip(SoC), a relaxation oscillator with stable output characteristics according to PVT(process, voltage and temperature) fluctuation require a low area and a low power. In this paper, we propose a solution to reduce the current loss caused by parasitic components in the conventional relaxation oscillator. Since the slew rate of the bias current and the capacitor are adjusted to be the same through the proposed solution, a relaxation oscillator with low area characteristics is designed for the same clock source frequency implementation. The proposed circuit is designed using the TSMC CMOS 0.18um process. The Simulation results show that the relaxation oscillator using the proposed solution can prevent the current loss of about $279{\mu}A$ and reduce the total chip area by 20.8% compared with the conventional oscillator in the clock source frequency of 96 MHz.

• IEIE Transactions on Smart Processing and Computing
• /
• v.3 no.6
• /
• pp.404-409
• /
• 2014

This paper presents a Spread Spectrum Clock Generator (SSCG) based on Relaxation oscillator using Up/Down Counter. The current is controlled by a counter and the spread spectrum of the Relaxation Oscillator. A Relaxation Oscillator with temperature compensation using the BGR and ADC is presented. The current to determine the frequency of the Relaxation Oscillator can be controlled. The output frequency of the temperature can be compensated by adjusting the current according to the temperature using the code that is the output from the ADC and BGR. EMI Reduction of SSCG is 11 dB, and Spread down frequency is 150 kHz. The current consumption is $600{\mu}A$ from 5V and the operating frequency is from 2.3 MHz to 5.75 MHz. The rate of change of the output frequency with temperature was approximately ${\pm}1%$. The SSCG is fabricated in a 0.35um CMOS process with active area $250um{\times}440um$.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.2
• /
• pp.202-207
• /
• 2015

A CMOS relaxation oscillator, with high robustness over process, voltage and temperature (PVT) variations, is designed in $0.18{\mu}m$ CMOS. The proposed oscillator, consisting of full-differential charge-discharge timing circuit and switched-capacitor based voltage-to-current conversion, could be expanded to a simple open-loop frequency synthesizer (FS) with output frequency digitally tuned. Experimental results show that the proposed oscillator conducts subcarrier generation for frequency-modulated ultra-wideband (FM-UWB) transmitters with triangular amplitude distortion less than 1%, and achieves frequency deviation less than 8% under PVT and phase noise of -112 dBc/Hz at 1 MHz offset frequency. Under oscillation frequency of 10.5 MHz, the presented design has the relative FS error less than 2% for subcarrier generation and the power dissipation of 0.6 mW from a 1.8 V supply.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.9
• /
• pp.798-805
• /
• 2015

This paper proposes Relaxation Oscillator with Random Number Generator to minimize electromagnetic interference (EMI) noise. DC-DC Converter with Relaxation Oscillator is presented how much spurious noise effects to RF Receiver system. The main frequency of the proposed Relaxation oscillator is 7.9 MHz to operate it and add temperature compensation block to be applied to the frequency compensation in response to temperature changes. The DC-DC Converter Spurious noise is reduced up to 20 dB through changing frequency randomly. It is fabricated in $0.18{\mu}m$ CMOS technology. The active area occupies an area of $220{\mu}m{\times}280{\mu}m$. The supply voltage is 1.8 V and current consumption is $500{\mu}A$.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.16 no.6
• /
• pp.728-735
• /
• 2016

A 70 MHz temperature-compensated on-chip CMOS relaxation oscillator for mobile display driver ICs is proposed to reduce frequency variations. The proposed oscillator compensates for frequency variation with respect to temperature by adjusting the bias currents to control the change in delay of comparators with temperature. A bandgap reference (BGR) is used to stabilize the bias currents with respect to temperature and supply voltages. Additional temperature compensation for the generated frequency is achieved by optimizing the resistance in the BGR after measuring the output frequency. In addition, a trimming circuit is implemented to reduce frequency variation with respect to process. The proposed relaxation oscillator is fabricated using 45 nm CMOS technology and occupies an active area of $0.15mm^2$. The measured frequency variations with respect to temperature and supply voltages are as follows: (i) ${\pm}0.23%$ for changes in temperature from -30 to $75^{\circ}C$, (ii) ${\pm}0.14%$ for changes in $V_{DD1}$ from 2.2 to 2.8 V, and (iii) ${\pm}1.88%$ for changes in $V_{DD2}$ from 1.05 to 1.15 V.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.735-738
• /
• 2002

This paper a new simple PWM (Pulse Width Modulation) signal generation based on modified relaxation oscillator is introduced. Its advantages of the proposed principle are that the precise PWM signal can be easily achieved with a high frequency range up to several megahertz and a low-voltage power supply. The proposed circuit can accept either voltage or current modulating signal. It is very suitable for developing into Integrated Circuits (ICs) form in communication applications. The simulation and experimental results are also depicted, they shown good agreement with theoretical anticipation.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.12
• /
• pp.1494-1500
• /
• 2004

A zero-dimensional direct simulation Monte Carlo(DSMC) model is developed for simulating diatomic gas including vibrational kinetics. The method is applied to the simulation of two systems: vibrational relaxation of a simple harmonic oscillator and translational-rotational-vibrational energy exchange process under heating and cooling. In the present DSMC method, the variable hard sphere molecular model and no time counter technique are used to simulate the molecular collision kinetics. For simulation of diatomic gas flows, the Borgnakke-Larsen phenomenological model is adopted to redistribute the translational and internal energies.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.2
• /
• pp.194-201
• /
• 2015

A frequency modulated ultra-wideband (FM-UWB) transmitter with a high-robust relaxation oscillator for subcarrier generation and a dual-path Ring VCO for RF FM is proposed, featuring low power and low complexity. A prototype 3.65-4.25 GHz FM-UWB transceiver employing the presented transmitter is fabricated in $0.18{\mu}m$ CMOS for short-range wireless data transmission. Experimental results show a bit error rate (BER) of $10^{-6}$ at a data rate of 12.5 kb/s with a communication distance of 60 cm is achieved and the power dissipation of 4.3 mW for the proposed transmitter is observed from a 1.8 V supply.

• ETRI Journal
• /
• v.33 no.1
• /
• pp.132-135
• /
• 2011

In this letter, we study the contemporary technologies for making ferroelectric films and the possibility of using the oscillator model of PZT-22 to analyze its ferroelectric properties. The material showed permittivity dispersion at 65 KHz and 88.5 KHz. We obtained relative attenuation ${\gamma}$, relaxation time ${\tau}$, and ${\varepsilon}_{max}$ of the material as 0.0008319, 0.5 s, and 603.438, respectively.