Synchronous buck regulators are widely used in industrial and infrastructure applications to step down 12V rails to POL inputs as low as 0.6V for MCUs, FPGAs, memory and peripheral I/Os. Overcurrent protection (OCP) is essential to protect these switching regulators from damage by excessive current. This white paper reviews several popular OCP schemes, and explains how these schemes work and how to implement them in buck regulators. We will also discuss the practical considerations examined by power supply designers to help them make the most appropriate choices for their applications.