Semiconductor integrated circuit having a clock recovery circuit
US6281725A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 1999 |
| Grant date | Aug 28, 2001 |
| Priority date | — |
| Expiry date | Jun 22, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/0008
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A clock recovery circuit is provided for use in a memory with a clock synchronized interface or the like, wherein an external clock is temporarily intercepted to shorten the lock-in time when an internal clock is to be generated from the external clock. The clock recovery circuit includes a delay circuit array, into which an external clock is inputted, for generating a plurality of reference clocks, a control circuit for comparing the phases of the external clock and of the plurality of reference clocks and detecting the number of delay stages of the delay circuits required for locking in, and latching circuit for holding the number of delay stages required for locking in. Once synchronism is detected and the number of delay stages required for locking in are held in the latching circuit, the generation of the internal clock can be resumed in a short period of time even if the supply of the external clock is temporarily suspended.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.