Relaxation oscillator

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

Explaining Hysteresis in Electronic Circuits: Robust Simulation and Design Examples

Abstract: We show how the hysteresis behavior in electronic circuits can be explained in a robust manner using PSpice transient simulations. Furthermore, we design a novel circuit for three-segment nonlinear characteristic shaping and show how this circuit can be used to produce hysteresis loops. The realization of relaxation oscillators is then given as a typical application.

Power supply start circuit

Abstract: A start circuit (70) for starting the generation of pulse width modulated switching pulses is disclosed for use in a DC/DC switching converter power supply. The starting circuit (70) is responsive to the initiation of a DC voltage source and starts the operation of a pulse generator (60). The starting circuit (70) also includes a relaxation oscillator (71) connected to the DC voltage source for periodically generating a start pulse at a predetermined frequency. On going power is coupled to the pulse generator (60) once the generator begins operation. The relaxation oscillator (71) is selectively disabled by a disabling circuit (90, 92, 94) when the pulse generator (60) is powered by the ongoing power supplied by the power supply during normal operation. The start circuit includes means (107) for delaying the disabling of the relaxation oscillator (71) for a preselected period after shutdown of the power supply and includes a rapid start circuit (300) for reducing the time between restoration of input power and the operation of the start circuit (70).

Programmable oscillator using one capacitor

Abstract: A programmable oscillator comprising a switching circuit, a first driver circuit, and a second driver circuit, the oscillator being programmable to switch at a first switching frequency or a second switching frequency by utilizing only one external capacitor and two external resistors. Only one driver circuit is active at a time to charge and discharge the capacitor at one of the switching frequencies. The driver circuits are made active or inactive by a control circuit.

Voltage controlled oscillator with switching bias

Abstract: Provided is a voltage controlled oscillator to which a switching bias technique is applied so as to lower flicker noise of a bias circuit and enhance phase noise characteristics, thereby reducing the overall chip area to make it possible to achieve integration. A common mode voltage applied to the bias circuit is negatively fed back to an oscillation waveform. Therefore, it is possible to stabilize the magnitude of the oscillation waveform of the voltage controlled oscillator with respect to a change in an external condition.

Horizontal deflection circuit with a start-up power supply

Abstract: In a horizontal deflection circuit, a horizontal oscillator, energized by a supply voltage, develops a horizontal frequency switching signal. A deflection outputs stage is responsive to the switching signal and generates scanning current in a horizontal deflection winding. After commencement of oscillator operation, the voltage developed across a secondary winding of a flyback transformer is rectified and filtered and applied to the horizontal oscillator as the oscillator energizing supply voltage. A start-up supply for developing the oscillator supply voltage during an initial interval includes a source of voltage that is available for use prior to the commencement of oscillator operation, a capacitor, a charging circuit for charging the capacitor from the available voltage source, and a controllable switch coupled to the capacitor and to the oscillator. After the charging circuit has charged the capacitor to a predetermined threshold voltage level, the controllable switch is made conductive to apply the capacitor voltage to the oscillator to commence oscillator operation. The switch is arranged with the capacitor as a relaxation oscillator to begin discharging the capacitor by the load current drawn by the horizontal oscillator. Should the capacitor discharge to a lower threshold level before the flyback-derived supply voltage is developed, the relaxation oscillator changes states to disconnect the horizontal oscillator from the capacitor to initiate a capacitor recharging cycle.