Patent ID: 7348835

Claim:
A midpoint potential generating circuit for use in a semiconductor device, comprising: a booster power supply circuit that boosts a first supply voltage into a second supply voltage and supplies the second supply voltage to an internal circuit of the semiconductor device; at least two first and second capacitors that are connected in series; a first voltage dividing resistor circuit that divides the second supply voltage outputted from the booster power supply circuit to generate two voltages of an upper limit and a lower limit; a second voltage dividing resistor circuit that is smaller in resistance than the first voltage dividing resistor circuit and divides the second supply voltage outputted from the booster power supply circuit to generate two voltages of the upper limit and the lower limit; and a bias supply circuit that controls a bias voltage that is supplied to the node between the first and second capacitors on the basis of the two voltage of the upper limit and the lower limit which are outputted from the second voltage dividing resistor circuit when the first supply voltage is lower than the predetermined value, and controls the bias voltage that is supplied to the node between the first and second capacitors on the basis of the two voltage of the upper limit and the lower limit which are outputted from the first voltage dividing resistor circuit when the first supply voltage is equal to or higher than the predetermined value.