公开(公告)号：US20190028106A1

公开(公告)日：2019-01-24

申请号：US15657250

申请日：2017-07-24

Applicant: NXP B.V.

Inventor： ANNE-JOHAN ANNEMA ,  JOS VERLINDEN

IPC: H03L7/083

Abstract: An oscillator system for an integrated circuit includes a first oscillator circuit, a second oscillator circuit, and calibration system. During a sampling routine, the calibration system is used to determine a sampled value based on a comparison of the output of the second oscillator and an external clock signal. The sampled value is stored in a memory. During a calibration routine, the calibration system determines a comparison value based on a comparison of the output of the second oscillator circuit and the output of the first oscillator circuit. The calibration circuit compares the comparison value with the sampled value to generate a tuning value to tune the frequency of the first oscillator circuit.