Abstract: With the urgent demand to intelligence and the highly sensibility to cost for LED lighting systems, and the existing intelligent LED control strategies face the issues of high cost and low reliability, a power electronic converter-based power and signal dual modulation method is proposed for LED intelligent dimming. It is based on power electronics-driven LED linear dimming system, adopting quaternary differential phase shift keying(QDPSK) to modulate ripples on the common power bus. Therefore, quaternary signal modulation, coupling and transmission are achieved without extra hardware. The basic principle of DC/DC power converter is studied from communication perspective, and reveals the implementation method of power and signal dual modulation in LED dimming systems. A tunnel LED intelligent dimming system is analyzed as an example from perspectives of the system structure, communication protocols, power noises, and communication rate. Finally, an experimental prototype is constructed to verify the feasibility of the proposed method.