State detection device, semiconductor integrated circuit device and vehicle

A semiconductor integrated circuit device, comprising:

• a state detection device, which is disposed in a power supply circuit including a feedback control unit configured to perform a feedback control based on a difference between a feedback voltage corresponding to an output voltage and a reference voltage and an output capacitor configured to smooth the output voltage, the state detection device configured to detect a state of the output capacitor and comprising:
• a target value varying unit, configured to increase a target value of the output voltage;
• and
• a detector, configured to detect the state of the output capacitor based on a change in the output voltage during a constant discharge time, while the output capacitor is charged when the target value of the output voltage increases, or while the output capacitor is discharged after the target value of the output voltage increases;
• and
• at least a part of the power supply circuit;
• an internal circuit, configured to receive the output voltage;
• and
• an RC circuit, including a resistor and the output capacitor, wherein
• the internal circuit is configured to be in a stop state during a discharge time, and
• the detector is configured to detect a capacitance of the output capacitor based on a time constant of the RC circuit.