An active clamping circuit. The active clamping circuit is applicable to a
DC-to-DC conversion circuit, and has an output terminal to supply an
output voltage to a load. In the active clamping circuit, a determining
circuit is coupled to the DC-to-DC conversion circuit to determine the
output detects the output voltage and to output a first enable signal
when the output voltage is higher than a first predetermined voltage. A
voltage adjustment circuit is coupled to the determining circuit to pull
low the output voltage according to the first enable signal. An inductor
has a first end coupled to the output terminal of the DC-to-DC conversion
circuit, and a diode is coupled between the inductor and an input
terminal of the DC-to-DC conversion circuit as a conductive path to
channel discharge current to the input terminal of the DC-to-DC
conversion circuit.