Error-prone and energy-efficient power supply for LEDs based on the detection of voltage drops across their power sources

摘要

The invention relates to an apparatus and a method for fault-tolerant power supply of LED groups (L1, L2, ... Lj, ... Ln) with electrical energy. A supply voltage (Vsup) is applied to a common first terminal of LED groups (L1, L2, ... Lj, ... Ln) through a controllable voltage regulator (DCDC). The respective current (I1, I2, ... Ij, ... In) through the respective LED groups (L1, L2, ... Lj, ... Ln) is by means of current sources (Iq1, Iq2, ... Iqj, ... Iqn) is set according to a respective current command value and modulated with a PWM modulation period. The voltage values of the voltage drops (VQ1, VQ2, ... VQj, ... VQn) via the respective current source (Iq1, Iq2, ... Iqj, ... Iqn) and / or the voltage drops (VL1, VL2, .. VLj, ... VLn) via the LED groups (L1, L2, ... Lj, ... Ln) are detected. They form an initial voltage vector. They are wired or wirelessly transmitted to a controller (CTR) or via the power supply line. The detection of the voltage drops takes place synchronously with the PWM modulation so as not to falsify the result. The recorded values of the voltage drops may be transmitted to the controller (CTR) in encrypted form. The control ICs that contain the power sources authenticate to the controller (CTR). The controller (CTR) discards the smallest voltage drop across the current sources or the largest voltage drop across the LED groups and unauthenticated voltage values. The regulation of the supply voltage (Vsup) occurs on the basis of at least one voltage value of the thus reduced voltage vector.