US 7,471,530 B2
Method and apparatus to reduce audio frequencies in a switching power supply
Balu Balakrishnan, Saratoga, Calif. (US); and Arthur B. Odell, Cupertino, Calif. (US)
Assigned to Power Integrations, Inc., San Jose, Calif. (US)
Filed on Oct. 04, 2006, as Appl. No. 11/543,518.
Prior Publication US 2008/0084723 A1, Apr. 10, 2008
Int. Cl. H02M 7/48 (2007.01)
U.S. Cl. 363—95  [363/97] 53 Claims
OG exemplary drawing
 
43. An apparatus, comprising:
a switch coupled to an energy transfer element of a power supply; and
a controller coupled to the switch to control the switch to switch on and off within a switching cycle, wherein a group having a predetermined number of two or more consecutive switching cycles is separated from a next group having the predetermined number of two or more switching cycles by a time of no switching and wherein the time of no switching is adjusted in closed loop to regulate a transfer of energy from an input of the power supply to an output of the power supply.