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:
Jun. 05, 2007
Filed:
Dec. 15, 2003
John M. Yarborough, Jr., Palo Alto, CA (US);
John M. Yarborough, Jr., Palo Alto, CA (US);
NXP B.V., Eindhoven, NL;
Abstract
An R-C oscillator () is configured to vary the two voltage levels that are used to control the oscillation, such that the variation in oscillation frequency with temperature is minimized. A first resistor (R) is used to control one of the voltage levels, and a second resistor (R) having a temperature coefficient that differs from the temperature coefficient of the first transistor is used to control the other voltage level. The first resistor (R) also controls the current used to charge and discharge the capacitor (C) used to effect the oscillation. By the appropriate choice of resistance values, the variations of the control voltages and current are such that the time to charge and discharge the capacitor (C) between the control voltages remains substantially constant with temperature. Preferably the resistance values are selected to also compensate for temperature variations in the delay of the feedback loop.