Relaxation oscillator

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

Trimmable low voltage oscillator

Abstract: The present invention relates to a trimmable oscillator circuit which comprises a comparator circuit operable to compare an output voltage of the oscillator circuit to a reference voltage and output a control signal in response thereto. The oscillator circuit further comprises an output capacitor, wherein a voltage at a node of the capacitor comprises the output voltage of the oscillator circuit, and the oscillator circuit also comprises a selectively trimmable charge/discharge circuit coupled between the comparator circuit and the output capacitor. The charge/discharge circuit is operable to charge or discharge the output capacitor based on the control signal, wherein a rate of charge or discharge is dictated by one or more user selectable control signals. Thus an oscillation frequency of the oscillator circuit may be trimmed.

Voltage variable operational amplifier relaxation oscillator

Abstract: A voltage variable digital clock utilizing an operational amplifier biased as a relaxation oscillator with a plurality of switch selectable capacitors for determining the operating frequency range of the oscillator and a field-effect transistor controlled resistance responsive to an error voltage for controlling the output frequency within the selected frequency range.

Tracking capacitance of liquid crystal devices to improve polarization rotation accuracy

Abstract: We report a capacitance tracking method for achieving arbitrary polarization rotation from nematic liquid crystals. By locking to the unique capacitance associated with the molecular orientation, any polarization rotation can be achieved with improved accuracy over a wide temperature range. A modified relaxation oscillator circuit that can simultaneously determine the capacitance and drive the rotator is presented.

A 1.3-µW −0.3/+0.27°C Inaccuracy Fully-integrated Temperature Sensor Based on a Pre-Charge Relaxation Oscillator for IoT applications

Abstract: This paper presents a CMOS fully-integrated temperature sensor based on a relaxation oscillator for IoT applications. To reduce power consumption, this sensor utilizes the half-period pre-charge compensation relaxation oscillator and uses a time-to-digital convertor (TDC) instead of analog-to-digital convertor (ADC) to count. Besides, the current distribution circuit is employed to improve temperature accuracy. The proposed sensor is implemented in 0.18 µm CMOS and occupies an area of 0.11 mm2. Measurement results show that the temperature sensor achieves an inaccuracy of −0.3/+0.27 °C across −15°C to 65°C after 2-point calibration. The chip consumes 1.3 µW at 27°C with a 650 mV voltage supply.

The Van Der Pol Four-Electrode Tube Relaxation Oscillation Circuit

Abstract: Relaxation oscillations of an electrical nature are defined, and the operation of a tetrode relaxation circuit is described in detail. The mechanism of frequency division is explained, and oscillograms of the oscillations in this circuit are shown, both of the free oscillation and of the oscillation as controlled in frequency division. The characteristics of the oscillator are discussed with reference to frequency drift and stability of frequency division. The period of the oscillator is shown to be approximately RC log V 1 /V 2 , where V 1 and V 2 are initial and final voltages on the condenser, respectively, during the discharge. V 1 /V 2 is shown to change very steeply with average internal grid resistance. Modifications are shown for increasing the frequency stability and over-all efficiency of the system, and for controlling the ratio of charging time to discharging time of the condenser. A further modification is suggested for making the internal grid resistance independent of filament voltage when the grid is positive.