A Low Power Relaxation Oscillator Exploiting Diode to Achieve Temperature Stability

Abstract

This paper introduces the process of learning and designing relaxation oscillator. Last semester, after reading several papers on oscillators, the relaxation oscillators were simulated under the guidance of the professor. In the simulation process, it is found that the temperature coefficient (TC) of the relaxation oscillator can be optimized. After a series of attempts, two schemes are designed to optimize the relaxation oscillator. One is to use diode to compensate the second-order TC, thus greatly improving the temperature stability. Secondly, the auxiliary common source stage (CS) is added to control the current conduction of CS stage, which reduces the power consumption by 20%. In this semester, a large number of simulations have been carried out on these two projects, and the expected results have been achieved. The design consumes 190nw from 0.4V power at 4.5MHZ, and the temperature coefficient (TC) is as low as 66ppm / ℃. The new efficiency (0.04nw/kHz) of the Megahertz range relaxation oscillator is realized.