Relaxation oscillator

About: Relaxation oscillator is a research topic. Over the lifetime, 1952 publications have been published within this topic receiving 22326 citations.

Voltage-controlled oscillator using a surface elastic wave resonator

Abstract: A Colpitts oscillator has an integrated circuit. The integrated circuit includes a transistor having an equivalent large size, a bypass capacitor connected between a collector of the transistor and a ground, a first feedback capacitor connected between a base and an emitter of the transistor, a second feedback capacitor connected between the emitter of the transistor and the ground, and an emitter follower connected to the emitter of the transistor. In a package, a stray reactance and a bonding wire are designed so as to agree with an element value and a Q value which can be used as parts of a resonator. A surface elastic wave resonator disposed outside the integrated circuit is connected between the base of the transistor and the ground. The oscillator is voltage controlled by a variable capacitance diode connected in series with the resonator.

Temperature compensation of an integrated low power inductive proximity microsensor

Abstract: A simple temperature compensation method for inductive proximity microsensors based on the differential relaxation oscillator has been developed and successfully tested. With this compensation and for the temperature range from −20°C to +80°C, an accuracy better than ±10 μm at 1 mm distance to an aluminum target has been measured. The microsensor has been integrated with a 3-V, 1-μm CMOS read-out circuit using a gold bumping layer to form a 3.8-mm side flat coil. The power consumption of the whole compensated microsystem is lower than 10 mW. To achieve this, the temperature behaviors of the whole microsensor and of its building elements, namely the sensing coil (nearby a target) and the read-out circuit, have been studied and a compensation method has been developed. The inductance of the integrated coil is temperature-independent in the frequency range up to 12 MHz, whereas its resistance depends mainly on the temperature coefficient of the conductor resistivity. The resonance frequency of the coil is not affected by temperature. In its principle, the electronic circuit has a temperature-dependent drift in the sensing distance range. This drift can, however, be compensated using a negative temperature coefficient resistor. Analytical derivations and simulation tools have been used for the choice of the optimal coefficient for a specific sensing distance range.

A novel schmitt trigger with low temperature coeficient

Abstract: A novel Schmitt trigger circuit, implemented by a RS trigger and two simple distinct inverters, is proposed. Its trigger levels are determined by two CMOS inverters. Contrasted with traditional six transistors Schmitt trigger, its temperature and supply voltage characteristics have been analyzed. Apply these two triggers into relaxation oscillator and the result shows that the proposed one in this paper has better performance over wide temperature range, whose temperature coefficient from 0degC to 85degC is 1/5 of traditional.

A square-rooting current-to-frequency converter

Abstract: A square-rooting current-to-frequency converter is presented in this paper. It has been designed by using one relaxation oscillator where a current-controlled resistor in CMOS technology with bisection of the input voltage is used instead of the ordinary resistor. In this way, the time constant of the relaxation oscillator is current-controlled. There is no need for a high stable voltage or current references in the proposed circuit. By appropriate setting of the process parameters of the MOSFETs used, the temperature variations of the output frequency can be made smaller than 7.6/spl times/10/sup -3/%/K. Experimental results confirm that the behavior of the proposed square-rooting CFC is in good agreement with the predictions of the analysis performed. According to these results, relative errors are less than 1% for the input current range from 35 /spl mu/A to 15 mA, and for the output frequency range from 1.45 kHz to 9.80 kHz.