The embodiment of the invention discloses a
voltage conversion circuit and a
switching power supply. A control module magnetizes or demagnetizes an
inductor by controlling alternate conduction of a main switching tube and a follow current switching tube in a
voltage conversion module, and charges and discharges a first
capacitor. A virtual inductive current
ripple signal is constructed through a virtual
ripple generation module, and the virtual inductive current
ripple signal replaces ESR information on a first
capacitor to be superposed on a feedback
voltage, so that after the feedback voltage is superposed with the virtual inductive current ripple
signal, the
phase difference between the feedback voltage and an inductive current is reduced, and the feedback voltage is reduced. The control module outputs a first
control signal according to a virtual inductive current ripple signal and a feedback voltage to control the
conduction time of the main switching tube and the follow current switching tube, so that the problem of
harmonic oscillation caused by a time-
lag effect between an inductive current and the output voltage on the first
capacitor is solved, and the generation of
harmonic waves is suppressed; the stability of the output voltage of the voltage conversion circuit is improved.