Clock oscillator
US5696469A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 1996 |
| Grant date | Dec 9, 1997 |
| Priority date | — |
| Expiry date | Feb 12, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F1/08
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A clock oscillator having a pair of pins adapted for coupling to an external crystal, a first one of such pair of pins being adapted for coupling to an external clock. A switch, formed on the chip, is provided for electrically decoupling the crystal excitation circuit from one of the pair of pins in response to a control signal. In accordance with one embodiment of the invention, the switch is disposed between the output of a crystal excitation circuit and the second one of the pair of output pins and, in another embodiment, the switch is placed in circuit between the input to the crystal excitation circuit and the first one of the pair of pins. In each of these embodiments, when the switch is in a first condition, clock pulses are prevented from being coupled to the second one of the output pins, either: by preventing the external clock from feeding the input to the crystal excitation circuit; or, by preventing the output of the crystal excitation circuit from feeding the second one of the pair of pins. With such an arrangement, when the external clock is used and fed to the first one of the pair of pins, clock pulses are electrically prevented from appearing at the second one of …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.