Relaxation oscillator

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

Noise Analysis of the Pulse-Width Modulator for Quasi-Digital Sensors

Abstract: Majority of available integrated and smart sensors are based on quasi-digitalization concept. A pulse modulation of the analog sensor output signal can be accomplished by using a fairly simple relaxation oscillator circuit. Pulse-width modulation (PWM) is commonly used in such applications, due to its ratiometric output that greatly reduces the error caused by the changes in the time constant of the oscillator. However, most of the literature that deal with the pulse-width modulators do not include the analysis of noise effects, which is important factor in optimizing the readout of PWM signal. In this article, we analyze the effects of noise in the simple dual-slope pulse-width modulator and provide an accurate noise model that can easily be adopted to any other type of pulse-width modulators. The model can be used to predict the jitter of the edges of output PWM signal and to analyze the effects of that jitter on the uncertainty of the measured duty-cycle for various PWM readout techniques.

Oscillator circuit whose frequency is voltage controllable which contains a comparator

Abstract: An oscillator utilizing a voltage comparator having hysteresis characteristics for producing a pulse train. The width of the pulses in the train is controlled by the charging rate of a capacitor coupled to one input of the comparator and the period of the pulse train is controlled by the discharge rate of this capacitor. The discharge rate and hence the oscillator frequency may be varied in response to a control voltage. Compensating elements ensure that the pulse width is highly stable with respect to temperature variations. The oscillator when in a feedback control circuit, produces oscillations at a frequency whose value is linearly related to the feedback control voltage.

Synchronizer for commonly clocked converters

Abstract: Apparatus for synchronizing the oscillators of several clocked direct voltage converters where each direct voltage converter has a control circuit with the oscillator as an integrated component and each control circuit has a connection for a capacitor and a connection for a resistor for defining the oscillator frequency. Commercial elements TDA 4714 and TDA 4716 are preferred as the control circuit. The synchronization is attained by adjusting the frequency of the oscillator of a first direct voltage converter to be higher than the frequency of the oscillators of the remaining direct voltage converters. A pulse sequence with an impulse frequency proportional to the oscillator frequency of the first direct voltage converter is transmitted by the first direct voltage converter to all of the other converters through an element that provides isolation between the different potentials. The pulses of the pulse sequence adjust a predetermined charging state for the capacitors of the other direct voltage converters. The adjustment is repeated at the frequency of the oscillator of the first direct voltage converter.

A linear, ultra wideband, low-power, 2.1–5 GHz, VCO

Abstract: A linear, Ultra Wideband, low-power VCO, suitable for UWB-FM applications is proposed, forming the main part of a UWB-FM transmitter. The VCO is designed in TSMC 90thinspacenm digital CMOS process and includes a Source-Coupled Multivibrator, used as current-controlled oscillator (CCO) which generates output frequencies between 2.1 and 5 GHz and a voltage-to-current (V-to-I) converter which translates the VCO input voltage modulation signal to current. Two single-ended inverter buffers are employed to drive either a differential or a single-ended UWB antenna. The presented VCO is designed for 1 V power supply and exhibits a linear tuning range of 2.1–5 GHz, a differential output power of −7.83 dBm±0.78 dB and low power consumption of 8.26 mW, including the output buffers, at the maximum oscillation frequency. It is optimized for a very high ratio of tuning range (81.69%) over power consumption equal to 9.95 dB. The desired frequency band of 3.1–5 GHz for UWB-FM applications is covered for the entire industrial temperature range (−40 to 125∘C). Copyright © 2010 John Wiley & Sons, Ltd.

Lamp oscillator for atomic frequency standards

Abstract: An apparatus for providing excitation of a vapor discharge lamp (12) includes a control circuit (20) for controlling an oscillator circuit (16) during an ignition mode of the vapor discharge lamp (12) to establish and maintain a substantially constant DC voltage at an output of an oscillator transistor (Q2) and to establish a current flow through the oscillator transistor (Q2) at a first current level sufficient to ignite the vapor discharge lamp (12), and for controlling the oscillator (10) after ignition of the vapor discharge lamp (12) to maintain the substantially constant DC voltage at the output of the oscillator transistor (Q2) while reducing the current flow through the oscillator transistor (12) from the first current level to a second current level, and in preferred embodiments, includes circuitry to suppress unwanted blocking oscillations and optimize the dynamic range of the control circuitry (20).