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:
Jan. 03, 2012
Filed:
Dec. 10, 2008
Michael George Negrete, Mountain View, CA (US);
Michael George Negrete, Mountain View, CA (US);
Linear Technology Corporation, Milpitas, CA (US);
Abstract
A flyback controller may generate a switching signal for controlling the delivery of input current into a primary winding of a transformer in a flyback converter that has a secondary winding in the transformer and that is driven by AC output from a dimmer control that is chopped at a phase angle based on a setting of the dimmer control. The flyback controller may include a tracking input configured to receive a dimmer output tracking signal that is representative of the instantaneous magnitude of the output from the dimmer control. The flyback controller may include an averaging circuit configured to average the dimmer output tracking signal so as to generate an average dimmer output signal that is representative of a time-averaged value of the dimmer output tracking signal. The flyback controller may be configured to cause the average output current in the secondary winding of the transformer to vary as a function of the average dimmer output signal when the phase angle exceeds a threshold. The flyback controller may be configured to generate the switching signal with a duty cycle that causes the luminance level of light produced by one or more LEDs to vary when the phase angle exceeds a threshold by what appears to the human eye to be a more linear function of the phase angle than if the luminance level actually varied as a linear function of the phase angle.