Frequency multiplier using delayed lock loop (DLL)
US6295328A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 17, 1998 |
| Grant date | Sep 25, 2001 |
| Priority date | — |
| Expiry date | Feb 17, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/00006
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency multiplier is provided that increases operational stability by using a Delay Locked Loop (DLL). The frequency multiplier includes a phase detector for detecting a phase difference between an input signal and a feed-back signal, a loop filter for outputting a control signal based on the phase difference detected by the phase detector and a voltage-controlled delay unit for varying a delay ratio of the input signal and outputting divided signals in accordance with the control signal from the loop filter. A first SR flip-flop receives a pair of earlier output signals that are divided into 1/4 and 2/4 period signals from the voltage-controlled delay unit and outputs a first duty cycle signal. A second SR flip-flop receives a pair of later output signals that are divided into 3/4 and 4/4 period signals from the voltage-controlled delay unit and outputs a second duty signal. A logic circuit such as an OR-gate receives the outputs from the first and second SR flip-flops and outputs a signal having a predetermined duty cycle, for example, a 50% duty cycle. The frequency multiplier further has reduced size and power requirements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.