Power supply semiconductor integrated circuit and power supply device

A power supply semiconductor integrated circuit, comprising:

• a first power supply semiconductor integrated circuit that comprises:
• a power supply input terminal to which a power supply voltage from a DC power supply is input;
• a power supply output terminal for outputting power an output voltage;
• a ground terminal to which a ground potential is applied;
• a first external terminal to which a second terminal of a first capacitor is connected, wherein the first capacitor is located externally and comprises a first terminal connected to the power supply input terminal;
• a second external terminal to which a second terminal of a second capacitor is connected, wherein the second capacitor is located externally and comprises a first terminal connected to the power supply input terminal;
• a first detector which detects a voltage of the first external terminal;
• a second detector which detects a voltage of the second external terminal;
• a fifth external terminal which outputs a signal from the first detector;
• and
• a sixth external terminal which outputs a signal from the second detector;
• a first switch which is located externally and provided between the first external terminal and a ground point;
• and
• a second switch which is located externally and provided between the second external terminal and a ground point, wherein;
• the first switch disconnects the second terminal of the first capacitor from a ground point upon receiving the signal of the first detector output from the fifth external terminal, and
• the second switch disconnects the second terminal of the second capacitor from a ground point upon receiving the signal of the second detector output from the sixth external terminal.

A power supply device, comprising:

• a power supply input terminal to which a power supply voltage from a DC power supply is input;
• a power supply output terminal for outputting an output voltage;
• a ground terminal to which a ground potential is applied;
• a first external terminal to which a second terminal of a first capacitor is connected, wherein the first capacitor is located externally and comprises a first terminal connected to the power supply input terminal;
• a second external terminal to which a second terminal of a second capacitor is connected, wherein the second capacitor is located externally and comprises a first terminal connected to the power supply input terminal;
• a first detector which detects a voltage of the first external terminal;
• a second detector which detects a voltage of the second external terminal;
• a first switch which is provided between the first external terminal and the ground terminal;
• a second switch which is provided between the second external terminal and the ground terminal, wherein;
• the first switch disconnects the second terminal of the first capacitor from a ground potential upon receiving a signal from the first detector, and
• the second switch disconnects the second terminal of the second capacitor from a ground potential upon receiving a signal from the second detector;
• and
• a voltage monitoring circuit which is located externally and monitors the voltage of the first external terminal and the voltage of the second external terminal.