Patent ID: 7205989

Claim:
A display apparatus characterized by comprising: a display area unit formed by arranging pixels each having an electrooptic device in a matrix manner; a vertical driving circuit for selecting the pixels of said display area unit by a unit of a row; a horizontal driving circuit for supplying an image signal to each of the pixels of the row selected by said vertical driving circuit; and a power supply voltage converting circuit for converting a single direct-current voltage into a plurality of direct-current voltages of different voltage values and then supplying the plurality of direct-current voltages to said vertical driving circuit and said horizontal driving circuit; wherein said power saving mode is a partial screen display mode in which information is displayed only in a partial area of said display area unit, and wherein said power supply voltage converting circuit formed by using a charge pump circuit having a switch device in an output unit includes: a first clamp circuit for diode-clamping a control pulse voltage for said switch device at the time of a start; and a second clamp circuit for clamping said control pulse voltage at a circuit power supply potential on the basis of a voltage outputted through said switch device at the time of an end of the start process.