Abstract
In this paper, a design of a current sensor in COT DC-DC Buck Converter for IoT applications is proposed. In the proposed design, current mirroring technique is used to improve the performance of COT buck DC-DC converter. The proposed structure can operate loop stability steadily according to the output capacitor and can improve the peak power conversion efficiency (PCE). By designing with the above configuration, output voltage ripple characteristics are stabilized when the ESR value of the output capacitor is small. The proposed circuit design results has been checked for the input voltage range of 4 V to 12 V, and the output current is aimed at least 1 A. The proposed circuit is implemented using 0.13 µm CMOS process. The proposed COT buck DC-DC converter used an external inductor of 2.2 uH with DCR resistor of 200 mΩ, VIN = 12 V, output capacitor of 10 µF and R ESR is 2mΩ. The load current is verified by changing the output resistor. The PCE is aimed over 90% at load current of 1 A. The light load efficiency achieved for load current of 100 mA is 89.7 % while the peak PCE is 92.5 %.