Analysis and Design of a Self-Charged Crystal Oscillator with Pulse Regulating Feedback Loop

A 32.768-kHz self-charged crystal oscillator (SCXO) using a proposed pulse regulator is presented. The general equation for pulse injection also provides a different insight for evaluating energy injected in crystal (XTAL). A robust oscillation with low power consumption is possible for a 1-V power supply. The proposed pulsed-regulated SCXO is designed in a 40-nm CMOS technology and the simulation shows 65.6% power reduction with process corner variation. In addition, the analytical locked amplitude of the proposed circuit is simulated and verified.