Relaxation oscillator

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

The effect of mismatch and disturbances on the quadrature relation of a cross-coupled relaxation oscillator

Abstract: Cross-coupled relaxation oscillators are capable of producing two stable and highly accurate, quadrature output signals. We present a complete high-level model of the cross-coupled relaxation oscillator in terms of circuit parameters, from which we obtain explicit expressions for duty-cycle, oscillation frequency and output phase relation. They predict the influence of mismatches and other disturbances such as delays, at circuit level. The results provide useful guidelines for the design of a high performance circuit of such an oscillator. The theoretical results are confirmed by simulation and by experiment.

Charge-status indicator

Abstract: A circuit arrangement for indicating the charge status of a batter in an electrical appliance includes a voltage comparator with hysteresis which detects the battery voltage, an oscillator driven by the voltage comparator, and an indicating device. The oscillator oscillates when the voltage is above a first threshold voltage and switches the indicating device to an active condition. The oscillator is blocked when the voltage is below a second threshold voltage and switches the indicated device to a passive condition.

A flexible low-power high-resolution integrated interface for capacitive sensors

Abstract: This paper presents a low-power high-resolution CMOS interface for capacitive sensors. The circuit is based on the use of a switched-capacitor charge amplifier, which converts the input capacitance to a voltage, which modulates the period of a relaxation oscillator. Auto-calibration is used to eliminate the undesired effects of transfer-parameter drift. The interface is suited for capacitive sensors with capacitance values from 1 pF up to 220 pF. Moreover, the measurement time can be set from about100 µs up to 50 ms. For the 10 pF range, parasitic capacitances up to 680 pF can be handled while the settling accuracy is more than 14 bits. For a measurement time of 1s, the resolution can be as high as 20 bits. In the 10 pF range, for parasitic capacitance up to 680 pF, the measured nonlinearity error is less than 5×10−5. All these features have been achieved with a chip consuming only 3 mm2 of silicon area and 5 mW of power.

Relaxation oscillators made of bridge-type Josephson contacts

Abstract: Nb, NbN, and Nb3Ge nanobridges on sapphire substrates with hysteretic I–V-characteristics are used as active elements in relaxation oscillators. Amplitudes of up to 350 mV and frequencies of up to 500 MHz could be generated, which make these oscillators useful for many applications. Linewidth and amplitude of the relaxation oscillations in dependence of nanobridge geometry are studied in some detail.

Plural oscillator circuit arrangement for rapidly resetting a computer circuit

Abstract: A circuit arrangement for providing a frequency for a computer circuit is suggested in which, in adition to a quartz oscillator, an additional oscillator which quickly begins to oscillate is provided. To ensure a quick operation of the computer circuit when switching on the computer circuit or after voltage dips, the oscillator which quickly begins to oscillate is first connected with the computer circuit when voltage is applied, so that the resetting processes can proceed very quickly. If the quartz oscillator has begun to oscillate and has reached a stable operating state, a switching is effected from the oscillator which quickly begins to oscillate to the quartz oscillator which takes over from the latter to continue providing a frequency for the computer circuit. The circuit arrangement can also contain a comparator whose inputs are connected to the respective oscillators and which compares the oscillator frequencies of the output signals from both oscillators. The frequency comparator can be connected to a switch which connects one or the other of the oscillators to the input of the computer circuit according to the comparison of oscillator frequencies in the comparator.