I2V2 Average Current Control for Modular LED Drivers

摘要

Present light-emitting diode (LED) drivers often exhibit difficulty in meeting the increasing demand for compact size, flexible multiphase configuration, accurate current regulation, and fast transient response. In this letter, we present an output-capacitorless modular LED driver that simultaneously achieves these attributes by the realization of monolithic integration and the employment of our proposed (IV2)-V-2 average current control. The proposed control based on pulsewidth modulation, considers the complete LED current profile to obtain the accurate current regulation and combines the feedforward signals of the inductor current, input voltage, and the output voltage to accelerate the transient response. To verify the proposed (IV2)-V-2 average current control scheme, we monolithically realize a modular LED driver that embodies a tiny 1.8 mu H inductor and supports an input voltage range of 5-18 V, output LED current of 1 A, switching frequency of 2 MHz, LED current settling time of 1.3 mu s, and the peak power efficiency of 94.5%. When being benchmarked against state-of-the-art counterparts, the proposed design features at least 2.6x smaller output inductor, 2.3x shorter settling time, and 2.5% higher peak power efficiency.