Verfahren zur Erkennung eines LED-Ausfalls, Controller dafür, Beleuchtungseinheit und Beleuchtungssystem

Details

Veröffentlichungs-Nr.

EP2717653

Aktenzeichen

EP12187154

Anmeldetag

4. Oktober 2012

Veröffentlichung

14. September 2016

Erteilung

14. September 2016

Rechtsraum

EP

IPC

H05B33/08

Abstract

Disclosed herein is a method of detecting an LED failure in a series-connected string of LEDs using a parameter indicative of a voltage difference between a voltage across the string at a predetermined relatively high current and a voltage across the string at a predetermined relatively low current, wherein at both the relatively low current and the relatively high current levels the current through an un-failed LED is dominated by minority-carrier diffusion current, The method comprises: determining a calibration value of the parameter during a first start-up phase; storing the calibration value in a store; determining a subsequent value of the parameter during a subsequent measurement phase; and, in response to a difference between the calibration value and the subsequent value exceeding a threshold, determining that an LED failure has occurred. The disclose extends to controllers configured to detect an LED failure in a string of LEDs, to LED lighting units comprising such controllers, and to lighting subsystems, for instance automobile lighting subsystems, which include one or more such LED lighting units.

Anmelder

Firma

NXP B.V.

Land

🇳🇱 Niederlande

Fachgebiete