Patent ID: 7030802
Filing Date: 2006-04-18
Classification: H03M

Abstract:
1. An AD converter having resistors arranged in series to generate at each of a connection point for each resistor a reference voltage to convert an analog value to a digital value, and semiconductor switches each constituted by a parallel combination of a PMOSFET and an NMOSFET, the parallel combination disposed one for each of the connection points, the AD converter, while applying a first voltage to a first gate electrode of the PMOSFET to bring the PMOSFET into conduction and a second voltage higher than the first voltage to a second gate electrode of the NMOSFET to bring the NMOSFET into conduction, generating the digital value on the basis of results of comparing the analog value with the reference voltages output from the semiconductor switches, the AD converter comprising: a control circuit operable at least either to step down the first voltage applied to the first gate electrode or to step up the second voltage applied to the second gate electrode.