Method and circuit arrangement for feeding a series circuit of n led units

Abstract

A method and a circuit arrangement for feeding n LED units (LED1 to LED5) of a lighting unit of a motor vehicle by way of a controlled power source (5) from a voltage source (2) having a fluctuating operating voltage (UB), in which the LED units (LED1 to LED5) are interconnected, and in particular k LED units (LED1 to LED5) of a series connection are short-circuited, when the operating voltage (UB) drops, taking a stored weighting with respect to the priority assigned to individual LED units into consideration, wherein current continues to flow simultaneously through (n−k) LED units. A memory unit (7) for storing information about weightings on the priority of certain LED units is assigned to the control unit (3) for activating the power source, a switching matrix (4′, S1 to S4), and in particular a circuit arrangement composed of n controlled switches (S1 to S4) that each bypass the LED units (LED1 to LED4, LED5) is provided, and the control unit (3) is configured to compared the operating voltage and/or the current (IS) of the power source to predefinable threshold values and to interconnect the LED units as a function of this comparison and the weighting.

Dependencies are inferred from the claim text.