Patent ID: 8525555

Claim:
A power detector comprising: a power voltage divider configured to divide a voltage of a power supply; a comparator for detection configured to compare a first output voltage of the power voltage divider to a reference voltage; a higher voltage side auxiliary comparator configured to compare a second output voltage of the power voltage divider, which is higher than the first output voltage, to the reference voltage; a lower voltage side auxiliary comparator configured to compare a third output voltage of the power voltage divider, which is lower than the first output voltage, to the reference voltage; an input switching signal generator configured to generate an input switching signal based on an output of the higher voltage side auxiliary comparator and an output of the lower voltage side auxiliary comparator; an input switch configured to switch inputs of the comparator for detection from the reference voltage and the first output voltage to an input voltage for non-use of the comparator in accordance with the input switching signal; a signal fixing unit configured to fix an output of the comparator for detection to a constant voltage when the input switch selects the input voltage for non-use of the comparator; and a power detection signal generator configured to generate a power detection signal based on the output of the lower voltage side auxiliary comparator and an output of the signal fixing unit.