A Novel Current Mirror Sensing Based Overcurrent Detection for Buck DC-DC Converter

An overcurrent detection method based on current mirror sensing was presented in this paper. Compared with the conventional overcurrent detection scheme, the sampling branch structure was optimized, which eliminated the negative effect of high peak voltage caused by capacitive coupling. And there is no extra branch introduced, so the circuit could still maintain low power consumption. The proposed method was realized in a 5MHz buck converter using 0.18μm CMOS process. As the simulation result shows, the presented overcurrent detection method has no peak voltage and works at low power consumption without tricky circuits.