Optimal Design of LED Array Combinations for CCM Single-Loop Control LED Drivers

This paper presents the optimal design of the light-emitting diode (LED) array combinations for three typical nonisolated continuous-conduction mode single-loop control LED drivers. Based on the LED Taylor series model and the equivalent circuits of these three LED drivers, the quality factor functions in their transfer functions of the control-to-output current are derived to predict the optimal combination of the LED arrays according to the given circuit and LED parameters to fulfill the requirement of critical damping and maximum efficiency power conversion, which happen at unity quality factor. The three prototype circuits of three LED drivers with 120 LEDs are presented to verify the optimal design of the corresponding LED array combinations through the theoretical, simulation, and experimental results.