Noise-shielding, switch-controlled load circuitry for oscillators and the like
US7132903B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 2003 |
| Grant date | Nov 7, 2006 |
| Priority date | — |
| Expiry date | Feb 16, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/0995
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A set of interconnected delay stages, such as a voltage-controlled oscillator, has switch-controlled load circuitry connected to each output of each delay stage in the oscillator ring. In one embodiment, for each delay stage output, the switch-controlled load circuitry includes a switch, a transistor, and a current source. The switch is connected between the corresponding delay stage output and the transistor gate, the current source is connected between a power supply and the transistor drain, and the transistor source is connected to ground. In such a configuration, the transistor's gate-to-source capacitance can be applied to the corresponding delay stage output by closing the switch, for example, for lower-frequency operations. In addition, the output impedance of the current source decouples the capacitive load from the power supply, thereby substantially shielding the oscillator ring from noise in the power supply.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.