Semiconductor device and switching power supply device

A semiconductor device, comprising:

• a first filter that generates a first output signal by performing first filtering processing on an input signal of the semiconductor device, the first filter having a first time constant;
• a second filter that generates a second output signal by performing second filtering processing on the first output signal, the second filter having a second time constant different from the first time constant;
• a first comparison circuit that compares the first output signal with a first threshold voltage, to thereby output a first level signal;
• a second comparison circuit that compares the second output signal with a second threshold voltage, to thereby output a second level signal;
• and
• an AND circuit that performs an AND operation on the first level signal and the second level signal,
• wherein the first comparison circuit is a first hysteresis comparator, and the second comparison circuit is a second hysteresis comparator, each of the first and second hysteresis comparators having a negative input terminal and a positive input terminal,
• wherein the first hysteresis comparator is configured to receive, via the negative input terminal thereof, the first output signal,
• wherein the second hysteresis comparator is configured to receive, via the negative input terminal thereof, the second output signal,
• wherein the first hysteresis comparator is configured to receive, via the positive input terminal thereof, the first threshold voltage that includes a first high potential level threshold voltage and a first low potential level threshold voltage,
• wherein the second hysteresis comparator is configured to receive, via the positive input terminal thereof, the second threshold voltage that includes a second high potential level threshold voltage and a second low potential level threshold voltage, and
• wherein the first high potential level threshold voltage is larger than the second high potential level threshold voltage, and the first low potential level threshold voltage is larger than the second low potential level threshold voltage.