Topic
Relaxation oscillator
About: Relaxation oscillator is a research topic. Over the lifetime, 1952 publications have been published within this topic receiving 22326 citations.
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Patent•
01 Apr 1998
TL;DR: In this article, an improved relaxation oscillator with automatic swing control feedback is proposed, which dynamically monitors the voltage swing across a capacitor and adjusts the oscillator threshold voltage, at which reversal of the polarity of the charging/discharging current occurs, to maintain the effective voltage swing at a constant level.
Abstract: A relaxation oscillator, such as a voltage controlled oscillator (VCO), with automatic swing control feedback which dynamically monitors the voltage swing across a capacitor and adjusts the oscillator threshold voltage, at which reversal of the polarity of the charging/discharging current occurs, to maintain the effective voltage swing at a constant level. The improved relaxation oscillator provides a very wide linear range of frequency variation versus control voltage (or current) and allows for the extendibility of linear operation to or near the maximum frequency that can be practically achieved by the oscillator circuitry.
14 citations
TL;DR: In this paper, a large-signal computer simulation of a GaAs millimeter-wave Gunn effect relaxation oscillator has been developed, which utilizes a Monte Carlo computation of the electron distribution behavior rather than relying on an analytical expression for the velocity-field characteristic.
Abstract: A large-signal computer simulation of a GaAs millimeter-wave Gunn-effect relaxation oscillator has been developed. This computer simulation utilizes a Monte Carlo computation of the electron distribution behavior rather than relying on an analytical expression for the velocity-field characteristic now known to be inaccurate at millimeter-wave frequencies. Results of this simulation are presented for a 70-GHz fundamental oscillator. The device simulated is consistent with currently produced millimeter-wave designs with an active length of 2.0 µm and doping density of 1 × 1016cm3. A peak efficiency of 2.4 percent with an output power of 144 mW was determined. The device can be characterized as operating in an accumulation transit mode, but with the proverbial "dead-zone" at the cathode.
14 citations
Patent•
22 Jan 1996
TL;DR: In this paper, a voltage-controlled oscillator circuit is proposed to operate at low power supply voltages and accomplishing low electric power consumption, which is capable of operating at high speeds.
Abstract: There is disclosed a voltage-controlled oscillator circuit capable of being operated at low power supply voltages and accomplishing low electric power consumption. The circuit permits the duty cycle to be controlled well. The circuit is capable of operating at high speeds. The circuit comprises a first and a second dynamic latch circuits producing oscillation output. Each dynamic latch circuit consists of a series combination of a P-channel MOS transistor and an N-channel MOS transistor. An output terminal is connected to the junction of these two transistors. The output from each latch circuit is inverted according to the voltage at the gate of each MOS transistor and dynamically latches the state of the output. This inversion is performed by turning on the MOS transistors by first and second capacitive elements and by first and second comparator circuits. The capacitive elements are charged and discharged by the outputs from the dynamic latch circuits. Voltages for charging the capacitive elements are applied to the comparator circuits. The switching operation is performed at a higher speed than where a flop-flop is used. Consequently, the oscillation frequency is improved. These MOS transistors do not simultaneously conduct and so electric currents passing through the transistors can be suppressed. Since the timing at which the inversion is made is determined by the charging rates of the capacitive elements, the duty cycle can be controlled well.
13 citations
Patent•
11 Jul 1972
TL;DR: In this article, the resistivity of a circuit path between sense electrodes in a volume of material and providing audio pulses of increasing frequency to cut-off where cutoff is indicative of a predetermined undesired quality of the volume of materials.
Abstract: System for monitoring the resistivity of a circuit path between sense electrodes in a volume of material and providing audio pulses of increasing frequency to cut-off where cut-off is indicative of a predetermined undesired quality of the volume of material. A unijunction transistor is utilized in a relaxation oscillator circuit and a predetermined value of resistance is connected in series path with a base electrode of the unijunction transistor to provide an alarm by oscillator cut-off when the current flow between probes becomes indicative that an undesired quality of the material has been reached, e.g., that saturation of soil by moisture is imminent or that drinking water has become polluted. A particular sense probe geometry provides accurate path measurements between the probes dependent upon the particular depth to which the probe tips have been inserted.
13 citations