公开(公告)号：US09838025B1

公开(公告)日：2017-12-05

申请号：US15233124

申请日：2016-08-10

Applicant: Apple Inc.

Inventor： Wei Deng ,  Dennis Fischette, Jr. ,  Gin Yee

IPC: H03L7/085 ,  H03L7/089

CPC classification number: H03L7/0891 ,  H03L7/1072 ,  H03L7/1075 ,  H03L7/113 ,  H03L7/18

Abstract: An apparatus includes circuitry and an oscillator circuit that may be configured to generate a clock signal dependent upon a control signal. The circuitry may be configured to perform a frequency measurement of the clock signal. In response to a determination that the frequency of the clock signal is greater than a first threshold, the circuitry may also be configured to perform a phase comparison between a divided clock signal and a reference clock signal, and to adjust a value of the control signal such that the adjusted value depends upon a result of the comparison. In response to a determination that the frequency of the clock signal is less than the first threshold, the circuitry may be configured to adjust the value of the control signal such that the adjusted value depends upon a result of the measurement.