A Novel Frequency-Adjustable RC Relaxation Oscillator with Low Power Consumption

In this paper, a novel frequency-adjustable resistive-capacitive (RC) relaxation oscillator is proposed based on the UMC55 process. In order to reduce the power consumption, the operational amplifiers instead of comparators are used in the traditional RC oscillator structure. Also, the key resistors and capacitors have been designed to be adjustable so as to adapt to process deviations. The overall structure is controlled by a negative feedback to oscillate the frequency, generating a 4-MHz clock output with a frequency adjustment range of $\pm 10\%$. The simulation results show that the adjustment function has a strong linearity and accuracy, and the RC oscillator can be adjusted to have the frequency of 4MHz under different process, voltage, and temperature conditions.