Relaxation oscillator based on temperature sensing

Abstract

The invention discloses a relaxation oscillator based on temperature sensing in the technical field of an oscillator. The relaxation oscillator comprises a temperature sensor, a logic circuit, a temperature control switch, an oscillation circuit and a high-precision clock; the temperature sensor generates a temperature reference voltage Vc1; the logic circuit compares the temperature reference voltage Vc1 with temperature judgment threshold voltages at different temperatures; and the temperature control switch receives result signals after comparison of the logic circuit. According to the invention, by alternatively charging a capacitor C1 and a capacitor C2 in one clock period, influence of an offset voltage of comparators is eliminated; the entire working temperature range is partitionedinto a plurality of small temperature intervals, and for each small temperature interval, positive temperature coefficient resistors and negative temperature coefficient resistors are proportioned ina proper ratio to form multiple paths of gateable resistance branch circuits; and meanwhile, a temperature sensing circuit is adopted to sense a current temperature and the resistance branch circuitcorresponding to the temperature interval is opened so as to obtain the resistors influenced a little by the temperature, thereby further improving frequency accuracy of the relaxation oscillator.

Description

technical field [0001] The invention relates to the technical field of oscillators, in particular to a relaxation oscillator based on temperature sensing. Background technique [0002] The relaxation oscillator has the characteristics of low cost, low power consumption, and medium frequency accuracy, and is often used to provide clock signals for low-power SoCs (System-on-Chip systems) such as radio frequency identification tag chips and wireless sensor chips. Oscillation frequency accuracy is a key performance metric for relaxation oscillators. However, with the continuous reduction of operating voltage and power consumption, the circuit performance is also increasingly affected by process deviation, temperature, and operating voltage fluctuations. Crystal oscillators are usually used to provide high-precision clock signals due to their high precision, low power consumption, and insensitivity to temperature. The crystal as an off-chip component increases component cost an...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a relaxation oscillator based on temperature sensing to solve the problem that the frequency of existing devices is greatly affected by temperature fluctuations in the background technology mentioned above

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