US 7,321,499 B2
Method of forming a power supply controller and device therefor
Josef Halamik, Roznov (Czech Republic); Radim Mlcousek, Frenstat (Czech Republic); and Pavel Londak, Hutisko Solanec (Czech Republic)
Assigned to Semiconductor Components Industries, L L C, Phoenix, Ariz. (US)
Filed on Nov. 02, 2005, as Appl. No. 11/264,107.
Prior Publication US 2007/0096699 A1, May 03, 2007
Int. Cl. H02M 3/335 (2006.01)
U.S. Cl. 363—21.1  [363/81; 323/222] 20 Claims
OG exemplary drawing
 
1. A semiconductor device having a power supply controller comprising:
a power switch;
a ramp generator configured to form a ramp signal having a periodically occurring period;
a first control circuit configured to form a switching drive signal having the period to operate the power switch and control an output voltage within a desired range around a target value;
a feedback circuit configured to form a feedback signal that is representative of the output voltage;
a current sense circuit configured to from a sense signal that is representative of a current through the power switch;
a second control circuit operably coupled to modulate one of the feedback signal or the sense signal and form a modulated control signal wherein the second control circuit is configured to use only one terminal of the semiconductor device to set a level of the modulation; and
the first control circuit operably coupled to use the modulated control signal to control a duty cycle of the switching drive signal.