Crystal amplifier with additional high gain amplifier core to optimize startup operation
US10367462B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 30, 2017 |
| Grant date | Jul 30, 2019 |
| Priority date | — |
| Expiry date | Oct 6, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B2200/0094
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A crystal amplifier for driving a crystal to oscillate at a resonant frequency including a controlled current source, a primary amplifier core, a high gain amplifier core, and a controller. Both amplifier cores are coupled in parallel, and each has an input coupled to an amplifier input node and an output coupled to an amplifier output node coupled across the crystal. The current source provides a core bias current to the source node. The controller enables the high gain amplifier core and sets the core bias current to a high current level to achieve a high negative resistance at a startup time, and then disables the high gain amplifier core and sets the core bias current to a lower steady state current level after oscillation is achieved. A level detector may be used for detecting oscillation and for determining when to adjust the core bias current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.