The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 07, 2006
Filed:
Jul. 03, 2003
Phillip Johnson, Hellertown, PA (US);
Gary Powell, Allentown, PA (US);
Harold Scholz, Allentown, PA (US);
Phillip Johnson, Hellertown, PA (US);
Gary Powell, Allentown, PA (US);
Harold Scholz, Allentown, PA (US);
Lattice Semiconductor Corporation, Hillsboro, OR (US);
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.