Oscillators – Electrical noise or random wave generator
Reexamination Certificate
2005-01-05
2008-09-09
Chang, Joseph (Department: 2817)
Oscillators
Electrical noise or random wave generator
C363S039000, C363S041000
Reexamination Certificate
active
07423494
ABSTRACT:
A method and apparatus for a spread-spectrum oscillator for a switched power converter is provided. The spread-spectrum oscillator includes a current waveform generation circuit, a capacitor, a switch, and a comparator. The capacitor is arranged to receive an oscillator current to provide a ramp voltage. The comparator is arranged to compare the ramp voltage with a reference voltage to provide an oscillator voltage. Further, the switch is arranged to discharge the capacitor when the oscillator voltage is asserted. The current waveform generation is arranged to, if enabled, provide at least a portion of the oscillator current as a triangle wave, or other type of modulating waveform suitable for spread-spectrum. Accordingly, the oscillator voltage is a spread-spectrum signal.
REFERENCES:
patent: 5488627 (1996-01-01), Hardin et al.
patent: 5631920 (1997-05-01), Hardin
patent: 2004/0090802 (2004-05-01), Pourseyed et al.
Hiroshi Sadamura et al., “Spread-Spectrum Clocking in Switching Regulators To Reduce EMI”, IEEE, Asia-Pacific Conference, Aug. 6-8, 2002 pp. 141-144.
M. Kuisma, “Variable Frequency Swtiching in Power Supply EMI-Control: An Overview”, IEEE AES Systems Magazine, Dec. 2003, pp. 19-22.
D.A. Stone et al., “Effect of Spread-Spectrum Modulation of Switched Mode Power Converter PWM Carrier Frequencies on Conducted EMI”, Electronics Letters, May 11, 1995, vol. 31, No. 10, pp. 769-770.
Chang Joseph
Darby & Darby P.C.
Gaffney Matthew M.
National Semiconductor Corporation
LandOfFree
Apparatus and method for a spread-spectrum oscillator for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for a spread-spectrum oscillator for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for a spread-spectrum oscillator for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3971758