A Single-Stage Low-Power AC–DC RGB-LED Driver With Switching Capacitor Control Scheme

This article presents a single-stage ac-dc light-emitting diode (LED) driver to achieve current regulation of red, green, and blue (RGB)-LED strings and ac-dc rectification with high power factor. The advantages of single-stage topology include single inductor, lower component counts, and smaller form factor. To adaptively and accurately regulate RGB-LED strings a switching capacitor control scheme is adopted with the properties of dynamic voltage difference detection and fast bus voltage hopping. The dynamic voltage difference detection precisely detects the voltage difference between the R- and GB-LED strings while the fast bus voltage hopping can immediately adjust the bus voltage level. The experimental results are shown to verify the theoretical analysis of the proposed LED driver, and the transient response time is less than 0.3 μs, which is at least three orders faster than the previous work. The peak efficiency of the proposed LED driver is up to 88.6%.