Switching power supply device and semiconductor device

A switching power supply device, comprising:

• a first rectifier circuit to which an AC input voltage is input;
• an input smoothing circuit that smoothes a DC input voltage output from the first rectifier circuit;
• a power converter circuit that converts the DC input voltage and outputs an output voltage;
• an input overvoltage detection circuit that generates an input overvoltage detection signal which is activated when the DC input voltage is higher than a first reference voltage level;
• and
• a discharge circuit that discharges stored charge stored in the input smoothing circuit, wherein
• the power converter circuit includes
• an energy conversion circuit to which the DC input voltage is input,
• a switching element that is connected to the energy conversion circuit and converts the DC input voltage by performing a switching operation to output the output voltage, and
• a switching control circuit that controls switching of the switching element,
• the switching of the switching element is stopped and discharging of the stored charge is started, with activation of the input overvoltage detection signal serving as a trigger, and
• when the input overvoltage detection signal is subsequently inactivated, the discharge is stopped and the switching of the switching element is resumed.