Abstract: Current loop circuit is one of the most important blocks in the current mode control DC-DC converters. The disadvantage of SENSEFET technique is analyzed and a novel current sensing circuit is proposed. The circuit can sense the inductor current through sensing the voltage across the power transistor. The sense ratio is hardly affected by temperature, process and supply voltage by using PMOS operated in linear region instead of resistance. The accuracy is enhanced by using body transconductance. Moreover, an adaptive slope compensation circuit which is able to adjust the slope according to the input and output voltage is presented. And the problem of over compensation is solved. The supply voltage range is 2.5~5.5V, work frequency is 1MHz. The proposed circuit can sense the inductor current changing from 0~3.5A accurately, and is suitable for high load current switching converter application.