This study proposes a fault-tolerant low-authority injection (LAI) current-sharing strategy for parallel DC-DC converters. A dual-operational-amplifier architecture is adopted, and a resistor–diode injection interface is introduced to limit the influence of the current-sharing loop on the primary voltage-regulation loop. A piecewise injection model and a simplified small-signal model are developed. A three-module 36 V/5 V half-bridge prototype is experimentally evaluated. At total output currents of 30 A and 90 A, the maximum current-sharing errors are approximately 6.0% and 6.4%, respectively. The converter also maintains stable operation during an intentional current-sharing-bus short-circuit test. The proposed LAI method provides a simple hardware-oriented solution that achieves effective current redistribution while restricting sharing-loop authority and improving fault tolerance.