Multi-mode crystal oscillators

摘要

Digital control of a crystal oscillator is implemented in a manner that allows frequency accuracy to be traded off dynamically with power consumption. The oscillator transitions between a less accurate/lower power mode and a high accuracy/higher power mode smoothly without requiring any external clock source during the transition. Power consumption is optimized because the crystal oscillator provides the clock source during transitions between the power modes and no other clock source is needed for these transitions. The system can also optimize the startup time and steady state power consumption independently.

主权项

1. An oscillator circuit, comprising:
a crystal oscillator bias circuit including a variable current mirror circuit; and a compensator circuit coupled to the crystal oscillator bias circuit, the compensator controlling operation of the crystal oscillator bias circuit in both a high power mode and a low power mode and controlling a ratio of the variable current mirror circuit.