High Accuracy CMOS Current Sensing Circuit for Current Mode Control Buck Converter

A current mode control ( CMC) integrated circuit (IC) with accuracy current sensing circuit (CSC) for buck converter is presented in this paper. With the proposed accurate integrated current sensor, the sensed inductor current, combined with the internal ramp signal, can be used for current mode DC-DC converter feedback control. The proposed CSC does not need an operational amplifier to implement, and has been fabricated with a standard 0.35 mum CMOS process. Simulation results show that the switching converter can be operated up to 1MHz. Which is suitable for signal cell lithium-ion battery supply applications, the power efficiency is over 85% for supply voltage from 2.5 V to 5 V and the output current is 200 mA. The performance of the proposed circuit is the good compared to the other circuits.