Inductor current reconstruction circuit, controller and switched-mode power supply

Abstract

An inductor current reconstruction circuit, a controller and a switched-mode power supply are disclosed. The inductor current reconstruction circuit includes an AC component reconstruction module having a charge/discharge capacitor, which is coupled to an inductor and configured to charge or discharge the charge/discharge capacitor, based on voltage difference between voltages at opposing ends of the inductor, or on voltage difference between a voltage at one end of the inductor and another voltage associated with the voltage at the end of the inductor, at a current proportional to the voltage difference. The AC component reconstruction module outputs a reconstructed signal characterizing an AC component in a current through the inductor. Inductor current reconstruction can be achieved without detecting ON/OFF states of power transistors. This makes the precision of inductor current reconstruction immune from influence of both any voltage drop across power transistors and simultaneous turn-off of upper and lower power transistors.