A Self-Calibration Technique for On-Chip Precise Clock Generator

This brief presents a self-calibration technique for on-chip precise clock generator used in the field of power electronics. In this technique, the operating frequency of the power grid is employed as the frequency reference to eliminate the frequency variation of the clock generator introduced by the fabrication process. To demonstrate the effectiveness of this technique, an on-chip relaxation oscillator has been designed, analyzed and verified with a 0.5-mu m standard CMOS technology. Measurement results show the oscillator with self-calibration operates at a frequency of about 103.7 kHz and draws 90 mu A current from a 5-V supply. 2.83% (3 sigma) frequency variation is achieved, which is more than 3x lower than the one without self-calibration.