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:
Nov. 22, 2011
Filed:
Jun. 20, 2007
Roelf Van Der Wal, Oss, NL;
Zadok Vitalis Socrates Kroeze, Oss, NL;
Roelf Van Der Wal, Oss, NL;
Zadok Vitalis Socrates Kroeze, Oss, NL;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A drive circuit () for driving a load () comprises: a power supply () for supplying an output current (I); a controller () for controlling the power supply; a current sensor () for generating a current sense signal (V); a controllable switch () in series with the output (), the switch being controlled by a mode controller (); wherein the mode controller in a reduced brightness mode generates its switch control signal (S) for the switch for alternatively opening and closing the switch. At the end of a current pulse, an average current value averaged over the pulse duration is calculated, compared with a reference value (V), and, if said average value is larger than the reference value, a duration for the next pulse pause is calculated such that an average value averaged over the entire pulse period is equal to the reference value.