Patent ID: 7439794

Claim:
A power source circuit adapted to output a first set potential which is set according to a first selection signal, or a second set potential which is set according to a second selection signal and higher than the first set potential, comprising: an output terminal adapted to output the first set potential or the second set potential; a first boosting circuit adapted to boost a voltage supplied from a power source and to output the boosted voltage to the output terminal; a second boosting circuit adapted to boost the voltage supplied from the power source and to output the boosted voltage to the output terminal; a voltage dividing circuit adapted to output a monitor potential by dividing the output potential outputted from the output terminal according to the first selection signal, or to output a monitor potential by dividing the output potential and reducing a voltage dividing ratio of the monitor potential with respect to the output potential according to the second selection signal; a comparison amplifier adapted to compare the monitor potential with a reference potential, and to output a flag signal for activating the boosting circuit when the monitor potential is lower than the reference potential; and a logic circuit adapted to receive the flag signal from the comparison amplifier, and when receiving the first selection signal, to output a first clock signal for making the first boosting circuit perform the boosting operation, and adapted to receive the flag signal from the comparison amplifier, and when receiving the second selection signal, to output a second clock signal for making the second boosting circuit perform the boosting operation, together with the first clock signal.