METHOD AND CIRCUIT ARRANGEMENT FOR OPERATION OF A MONITORED LIGHT-LED DIODE SERIES CIRCUIT AND LIGHTING DEVICE WITH SUCH A CIRCUIT ARRANGEMENT

Abstract

Method for operating a circuit arrangement (10, 12) with at least two series-connected LED arrangements (14, 16), each comprising at least one LED (D1, D5, D7, D8), and a current source circuit (18) also connected in series with the LED arrangements (14, 16), in which method the series connection of the LED arrangements (14, 16) and the current source circuit (18) is supplied with an electrical operating voltage to supply the LED arrangements (14, 16) with electrical energy in the intended lighting operation, wherein a value for the electrical operating voltage is detected and compared with a predetermined voltage reference value, and if the detected value for the operating voltage is lower than the voltage reference value, a first of the LED arrangements (16) is deactivated by means of a switching unit (22) connected in parallel with the first LED arrangement (16).characterized in that the first light-emitting diode arrangement (16) is supplied with a test voltage, a light-emitting diode arrangement current caused by the test voltage is detected by the first light-emitting diode arrangement, the light-emitting diode arrangement current is compared with a current reference value, and if the light-emitting diode arrangement current is smaller than the current reference value, the deactivation of the first light-emitting diode arrangement (16) by the switching unit (22) is blocked.

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