公开(公告)号：US11256283B2

公开(公告)日：2022-02-22

申请号：US16736776

申请日：2020-01-07

Applicant: Apple Inc.

Inventor： Meei-Ling Chiang ,  Dabin Zhang ,  Dennis M. Fischette, Jr. ,  Shaobo Liu ,  Yu Chen ,  Samed Maltabas

IPC: H03K23/00 ,  G06F1/04 ,  H03K7/06 ,  H03K23/58

Abstract: Systems, apparatuses, and methods for implementing a hybrid asynchronous gray counter with a non-gray zone detector are described. A circuit includes an asynchronous gray counter coupled to control logic. The control logic programs the asynchronous gray counter to operate in different modes to perform various functions associated with a high-performance phase-locked loop (PLL). In a first mode, the asynchronous gray counter serves as a frequency detector to count oscillator cycles within a reference clock cycle. In a second mode, the asynchronous gray counter serves as a coarse phase detector to detect a phase error between a feedback clock and a reference clock. In a third mode, the asynchronous gray counter serves as a multi-modulus divider to divide an oscillator clock down to create a feedback clock. Using a single asynchronous gray counter for three separate functions reduces power consumption and area utilization.

公开(公告)号：US20210208621A1

公开(公告)日：2021-07-08

申请号：US16736776

申请日：2020-01-07

Applicant: Apple Inc.

Inventor： Meei-Ling Chiang ,  Dabin Zhang ,  Dennis M. Fischette, JR. ,  Shaobo Liu ,  Yu Chen ,  Samed Maltabas

IPC: G06F1/04

Abstract: Systems, apparatuses, and methods for implementing a hybrid asynchronous gray counter with a non-gray zone detector are described. A circuit includes an asynchronous gray counter coupled to control logic. The control logic programs the asynchronous gray counter to operate in different modes to perform various functions associated with a high-performance phase-locked loop (PLL). In a first mode, the asynchronous gray counter serves as a frequency detector to count oscillator cycles within a reference clock cycle. In a second mode, the asynchronous gray counter serves as a coarse phase detector to detect a phase error between a feedback clock and a reference clock. In a third mode, the asynchronous gray counter serves as a multi-modulus divider to divide an oscillator clock down to create a feedback clock. Using a single asynchronous gray counter for three separate functions reduces power consumption and area utilization.