This paper investigates power line communication in digitally-controlled dc-dc converters. Communication between different dc-dc converters is obtained detecting the switching signal on the common bus voltage and using switching frequency modulation. Each converter operates at three different switching frequencies, the first associated to bit 1 transmission, the second to bit 0 transmission and the third associated to no transmission state. Simulation and experimental results on a 3.3 V-10 A dc-dc buck converter, where the communication architecture has been implemented in FPGA, confirm the proposed analysis and the performance achievable by the proposed power line communication techniques. For nominal switching frequency of 200 kHz, the maximum achievable baud rate in our experimental prototype is 8 kbit/s.
