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. 01, 2013
Filed:
Apr. 30, 2010
Xiaodong Zhan, Plano, TX (US);
Fred Greenfeld, Nederland, CO (US);
Xiangxu Yu, Shenzhen, CN;
Intersil Americas Inc., Milpitas, CA (US);
Abstract
An LED driver with open loop dimming including a full wave rectifier circuit, a DC/DC converter, and an oscillator circuit. The rectifier is configured to receive an input voltage in the form of an AC conductive angle modulated voltage and to provide a rectified voltage. The DC/DC converter converts the rectified voltage to an output voltage and an output current, where the output current has a magnitude which varies proportionately with a square of a quadratic mean of the input voltage. The oscillator circuit controls switching of the DC/DC converter with constant frequency and constant duty cycle. The DC/DC converter may be a flyback converter and may include a transformer operated in DCM. The driver may include output voltage and/or output current limit. The output current may be limited when the input voltage is within normal operating range of an AC line voltage from which the input voltage is derived.