DC micro-grids are getting increased attention around the world due to the paradigm shift in electricity generation and changing nature of the modern electrical loads. However, one of the major issues with dc micro-grids and other multi-converter systems is stabilization of the system against negative impedance instabilities caused by negative incremental resistance behavior of tightly regulated point-of-load converters. This paper presents a PWM based sliding mode controller for negative impedance stabilization of dc-dc converters in a dc micro-grid. The existence of sliding modes is proved. The proposed controller and simplified dc micro-grid are modeled in MATLAB SIMULINK and simulated response is studied to check the suitability of the proposed controller. Simulated response validates the effectiveness of the proposed controller with variations in the input voltage and the load. © 2014 IEEE.