The invention discloses a
switching power supply, which comprises an
inductor and a master switch, wherein the master switch is controlled to turn on and turn off, so that the output end of the
switching power supply outputs output
voltage; the
switching power supply further comprises a first
branch, a detection module and a
logic module, wherein the first
branch is connected to the
inductor in parallel and comprises a first switch and a
ringing suppression
resistor which are connected in series, and a connection node of the
inductor and the master switch is marked as a switching node; the detection module is suitable for detecting whether associated
voltage is smaller than
threshold voltage, the output end outputs a detection result, and the associated
voltage is associated with the voltage of the switching node; the first input end of the
logic module is coupled to the output end of the detection module and the second input end of the
logic module is coupled to the control end of the master switch; when the master switch is controlled to turn off and the detection result indicates that the associated voltage is smaller than the
threshold voltage, the logic module controls the first switch to turn on until the master switch is controlled to turn on, otherwise the logic module controls the first switch to turn off. According to the scheme of the invention, the
ringing can be suppressed, the cost is high and the stability is high.