Semiconductor device, DC-DC converter, and protective element

A DC-DC converter comprising:

• a first interconnect connected to a high voltage side power supply voltage;
• a second interconnect separate from the first interconnect, connected to the high voltage side power supply voltage;
• a switching circuit connected between the high voltage side power supply voltage and a low voltage side power supply voltage via the first interconnect, that selectively connects the high voltage side power supply voltage and the low voltage side power supply voltage to an output terminal;
• an inductor with a first end connected to the output terminal of the switching circuit;
• a capacitor connected between a second end of the inductor and the low voltage side power supply voltage;
• and
• a protective element connected in parallel with the switching circuit between the high voltage side power supply voltage and the low voltage side power supply voltage,
• the protective circuit including:
• a first p-type semiconductor region connected to the first interconnect;
• an n-type semiconductor region in contact with the first p-type semiconductor region and connected to the second interconnect;
• and
• a second p-type semiconductor region in contact with the n-type semiconductor region, spaced from the first p-type semiconductor region, and connected to the low voltage side power supply voltage.

A protective element connected in parallel with a protected circuit between a high voltage side power supply voltage and a low voltage side power supply voltage, comprising:

• a first p-type region formed in a semiconductor substrate;
• an n-type region formed in the semiconductor substrate, in contact with the first p-type region;
• a second p-type region formed in the semiconductor substrate, in contact with the n-type region, spaced from the first p-type region, and to which the low voltage side power supply voltage is applied;
• a first interconnect portion that is connected to the first p-type region, the high voltage side power supply voltage, and the protected circuit;
• and
• a second interconnect portion, which is separate from the first interconnect portion, that is connected to the n-type region and the high voltage side power supply voltage.