公开(公告)号：US11705861B1

公开(公告)日：2023-07-18

申请号：US17853070

申请日：2022-06-29

Applicant: Silicon Laboratories Inc.

Inventor： Mohamed M. Elkholy ,  Francesco Barale ,  Tiago Pinto Guia Marques ,  Steffen Skaug ,  Håkon Børli

IPC: H03B5/06 ,  H03B5/36 ,  H03L7/099

CPC classification number: H03B5/06 ,  H03B5/36 ,  H03B5/364 ,  H03L7/099 ,  H03B2200/0012

Abstract: A first three state driver injects a first clock signal into a crystal through an input node during a startup phase of a crystal oscillator and a second three state driver injects a second signal into the crystal through an output node during the startup phase. The first and second signals are anti-phase signals. The crystal oscillator circuit includes a first amplifier that is used during starting up and steady-state operation and includes a second amplifier. The injection through the input and output nodes is disabled after a fixed time. After injection ends, the second amplifier is turned on if voltage on the output node has reached a desired voltage and left off otherwise. If the second amplifier is turned on, the second amplifier is turned off when the voltage on the output node reaches the desired voltage.