CURRENT DETECTION CIRCUIT AND DC/DC CONVERTER PROVIDED WITH CURRENT DETECTION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a circuit for detecting a current flowing into an inductor, with a small loss. SOLUTION: An RC series circuit 11 is provided in parallel with an inductor L. The RC series circuit 11 is constituted by a resistance Ra and a capacitor Ca connected in series each other. A voltage, generated at both ends of the capacitor Ca is imparted to a detection circuit 12, and the detection circuit 12 detects an inductor current flowing through the inductor L based on the voltage. When the inductance of the inductor is defined as L, the parasitic resistance value of the inductor is defined as RL, the capacity of the capacitor Ca is defined as Ca and the resistance value of the resistance Ra is defined as Ra, the RC series circuit 11 is substantially designed so as to satisfy the expression L/RL=Ca.Ra.