Patent ID: 7893752

Claim:
A charge pump circuit for generating a predetermined negative voltage from an input voltage received from an input terminal, and for providing an output terminal with the predetermined negative voltage as an output voltage, the charge pump circuit comprising: a first capacitor having first and second terminals; a second capacitor connected between the output terminal and a reference voltage; a first switch configured to turn on/off according to a control signal, the first switch having first and second terminals, the first terminal being connected to the input terminal; a voltage control circuit configured to control a voltage provided to the first capacitor, the voltage control circuit being connected to the second terminal of the first switch and to the first terminal of the first capacitor, the voltage control circuit comprising: a constant voltage circuit; and a field effect transistor that has a control electrode that receives a constant voltage from the constant voltage circuit, wherein the field effect transistor is connected between the second terminal of the first switch and the first connection; a second switch configured to turn on/off according to the control signal, the second switch being connected between the second terminal of the first capacitor and the reference voltage; a first connection connected between the first capacitor and the voltage control circuit; a third switch configured to turn on/off according to the control signal, the third switch being connected between the first connection and the reference voltage; a second connection connected between the first capacitor and the second switch; a fourth switch configured to turn on/off according to the control signal, the fourth switch being connected between the second connection and the output terminal; and a control circuit part configured to control the first switch, the second switch, the third switch, and the fourth switch, wherein the voltage control circuit provides a current that flows through the first switch to the first capacitor, and controls the voltage of the first connection such that the voltage of the first connection is lower than a predetermined voltage.