A voltage supplying device comprises a reference voltage generating circuit, a
first impedance conversion circuit for performing the impedance conversion on a
reference voltage, a digital-analogue converter (DAC) and a second impedance conversion
circuit for performing the impedance conversion on a voltage from the DAC. A first
switching element is provided between the output of the second impedance conversion
circuit and the load capacitance. A first bypass line is provided for bypassing
the second impedance conversion circuit and the first switching element, and a
second switching element is provided on the bypass line. In the first period of
the charging period, the output of the second impedance conversion circuit is supplied
to the load capacitance. In the second period of the charging period, the output
of the DAC is supplied to the load capacitance.
