BP3368B is a high-performance two-stage architecture constant current control chip applied to medium and high-power LED lighting. A single chip can realize the combined control of boost PFC and non-isolated Buck constant current. BP3368B can achieve high-precision and high PF constant current output in the full voltage range and realize flicker-free lighting. The two-stage switching power supplies controlled by the BP3368B chip both operate in the critical conduction and quasi-resonant modes of inductive current, thereby achieving higher conversion efficiency and lower electromagnetic interference (EMI). The Boost boost inductor of BP3368B can adopt a single-winding architecture. At the same time, it integrates a high-voltage startup function. The advanced constant current algorithm is adopted in the Buck topology at the later stage, which can achieve excellent line regulation and load regulation, and at the same time simplifies the BOM and system cost.