Multiphase interleaved boost DC-DC converters are typically used as a fuel cell power conditioner due to their low input ripple current. This paper presents analysis and design of a 2-phase interleaved boost DC-DC converter controlled by a single chip DSP to enhance reliability and flexibility. The PI regulator for the output voltage control was tuned by the extended symmetrical optimum method to optimally operate in the fuel cell ohmic region with a guaranteed phase margin of 45 for the entire fuel cell voltage range. The set point weighting technique was used for soft starting, which was effective. The effects of switching and sampling time delays were analysed and compensated. Experimental results of the 1-kW, 120-V prototype converter connected with a PEM fuel cell stack closely agreed with simulation results in MATLAB/Simulink. The DSP-based fuel cell converter has the potential for further development as a compact fuel cell generator or fuel cell electric vehicle with embedded online diagnosis and fault-tolerant operation. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.