Power supply apparatus and error detecting method for power supply apparatus

A power supply apparatus comprising:

• a trans circuit configured to convert an input voltage into an output voltage by adjusting switching of the input voltage;
• an output voltage detection circuit configured to detect the output voltage;
• a compensation circuit configured to generate a control value controlling a duty ratio of the switching such that a value of the detected output voltage coincides with a target value for the output voltage;
• an input voltage detection circuit configured to detect the input voltage;
• an estimation circuit configured to:
• estimate a representative value of an allowed range of the control value in accordance with the target value and a value of the detected input voltage,
• set an upper limit value of the allowed range to a value larger than the representative value, and
• set a lower limit value of the allowed range to a value smaller than the representative value;
• and
• an adjustment circuit configured to adjust the control value so as to stop the switching when the control value falls outside the allowed range.