US 7,400,122 B2
Method and apparatus for reducing audio noise in a switching regulator
Balu Balakrishnan, Saratoga, Calif. (US); Alex B. Djenguerian, Saratoga, Calif. (US); and Kent Wong, Fremont, Calif. (US)
Assigned to Power Integrations, Inc., San Jose, Calif. (US)
Filed on Mar. 27, 2007, as Appl. No. 11/729,262.
Application 11/729262 is a continuation of application No. 11/404688, filed on Apr. 14, 2006, granted, now 7,211,991.
Application 11/404688 is a continuation of application No. 11/100065, filed on Apr. 05, 2005, granted, now 7,045,994.
Application 11/100065 is a continuation of application No. 10/888782, filed on Jul. 08, 2004, granted, now 6,900,622.
Application 10/888782 is a continuation of application No. 10/659911, filed on Sep. 11, 2003, granted, now 6,784,646.
Application 10/659911 is a continuation of application No. 10/285266, filed on Oct. 30, 2002, granted, now 6,667,605.
Application 10/285266 is a continuation of application No. 09/634237, filed on Aug. 08, 2000, granted, now 6,525,514.
Prior Publication US 2007/0285068 A1, Dec. 13, 2007
This patent is subject to a terminal disclaimer.
Int. Cl. G05F 1/40 (2006.01)
U.S. Cl. 323—277  [323/283; 363/131] 10 Claims
OG exemplary drawing
 
1. A method, comprising:
switching a power switch coupled in series with an energy transfer element of a power supply with a drive signal to regulate a power level of an output of the power supply;
adjusting an on/off cycle ratio of the drive signal responsive to the output of the power supply;
selecting one of a plurality of current limit settings responsive to the output of the power supply;
limiting a current through the power switch to the selected one of the plurality of current limit settings, wherein a range of power levels delivered to the output of the power supply when one of the current limit settings is selected overlaps with a range of power levels delivered to the output of the power supply when another of the current limit settings is selected.