Patent ID: 8742834

Claim:
A control circuit for a negative voltage charge pump circuit configured to receive an input voltage and to generate a negative output voltage, the control circuit comprising: a first switch arranged between one terminal of a flying capacitor and an input terminal; a second switch arranged between the aforementioned one terminal of the flying capacitor and a ground terminal; a third switch arranged between the other terminal of the flying capacitor and the ground terminal; a fourth switch arranged between the other terminal of the flying capacitor and one terminal of the output capacitor; a control unit configured to alternately repeat a first state in which the first switch and the third switch are on and a second state in which the second switch and the fourth switch are on; and a voltage detection unit configured to compare the output voltage that occurs at the aforementioned one terminal of the output capacitor with a predetermined negative voltage, and to generate an abnormality detection signal which is asserted when the output voltage is higher than the threshold voltage, wherein, when the abnormality detection signal is asserted, the control unit raises the on resistance of the first switch in the on state.