Apparatuses, methods, and systems for glitch-free clock switching

US9509318B2 · kind B2 · utility

Assignee

• QUALCOMM Incorporated · US

Inventors

• Chad Everett Winemiller · Cary, US
• Behnam Amelifard · Los Angeles, US
• Kenneth Luis Arcudia · Ridgeland, US
• Jon Boyette · Holly Springs, US
• Chia Heng Chang · San Diego, US
• Russell Coleman Deans · Chapel Hill, US
• Kevin Wayne Spears · Raleigh, US

Key dates

• Filing date: Mar 13, 2015
• Grant date: Nov 29, 2016
• Expiry date: Mar 13, 2035

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02D10/00
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

Aspects disclosed in the detailed description include apparatuses, methods, and systems for glitch-free clock switching. In this regard, in one aspect, an electronic circuit is switched from a lower-frequency reference clock to a higher-frequency reference clock. An oscillation detection logic is configured to determine the stability of the higher-frequency reference clock prior to switching the electronic circuit to the higher-frequency reference clock. The oscillation detection logic derives a sampled clock signal from the higher-frequency reference clock, wherein the sampled clock signal has a slower frequency than the lower-frequency reference clock. The oscillation detection logic then compares the sampled clock signal against the lower-frequency reference clock to determine the stability of the higher-frequency reference clock. By deterministically detecting stability of a reference clock prior to switching to the reference clock, it is possible to avoid premature switching to an unstable reference clock, thus providing glitch-free clock switching in the electronic circuit.