Patent ID: 7248095

Claim:
A bus driving device comprising: a driver circuit for driving a bus line, the driver circuit including an MOS transistor whose well is separated from other circuits; and a voltage control section for adjusting, in accordance with a level of a signal in the bus line, a value of a well voltage, so that a threshold voltage of the MOS transistor is kept at a predetermined target value, wherein the voltage control section includes: a voltage difference finding section for finding a difference between the target value and the threshold voltage of the MOS transistor, based on the level of the signal in the bus line; and a voltage output section for outputting the well voltage so as to compensate the difference found by the voltage difference finding section, and the voltage output section includes: a selecting voltage finding section for finding a selecting voltage based on the difference; and a selection output section for selecting, from a plurality of pre-generated voltages, the well voltage in accordance with the selecting voltage found by the selecting voltage finding section.