Relaxation oscillator

Abstract

The invention provides a relaxation oscillator, comprising a first comparator, a second comparator, an SR latch and a capacitor control module. An input terminal of the first comparator is coupled with a capacitor control module and an external reference threshold voltage, and an output terminal of the first comparator is coupled with an input terminal of the SR latch. An input terminal of the second comparator is coupled with the capacitor control module and the external reference threshold voltage, and an output terminal of the second comparator is coupled with the input terminal of the SR latch. An output terminal of the SR latch is coupled with an input terminal of the capacitor control module. A bias current input terminal of the capacitor control module is coupled to an external biascurrent source. A control signal is generated by inputting a first comparison signal generated by the first comparator and a second comparison signal generated by the second comparator into the SR latch according to the external reference threshold voltage, and a first capacitor and a second capacitor are controlled to periodically charge and discharge to generate an oscillation signal accordingto a bias current of the external bias current source and the control signal output from the SR latch.

Description

technical field [0001] The invention relates to the technical field of oscillators, in particular to a relaxation oscillator. Background technique [0002] A relaxation oscillator is a nonlinear electronic oscillator circuit capable of generating a repetitive output signal of a triangular or square wave. The circuit consists of a feedback loop, usually a switching device such as a transistor, comparator, relay, operational amplifier, and active device inductor or capacitor. [0003] It repeatedly charges the capacitor with current until it reaches a threshold level, and then discharges it again. The period of the oscillator depends on the time constant of this capacitive circuit. Capacitors switch abruptly between charge and discharge modes, creating repetitive waveforms that vary discontinuously. This scheme is usually used to generate low frequency signals. If we want to generate a high-frequency signal, we need a smaller capacitor or a larger current, but a smaller ca...

AI Technical Summary

Problems solved by technology

If we want to generate a high-frequency signal, we need a smaller capacitor or a larger current, but a smaller capacitor will cause an error in the actual on-chip capacitor value, resulting in a large deviation between the actual frequency and the theoretical frequency

But if the current is increased, the actual chip current consumption will increase

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