A digital-to-analog converter generates a monotonic sequence of reference voltages and selects an arbitrary pair of reference voltages, adjacent in the monotonic sequence. One of the selected reference voltages is supplied through a resistor and a switching device, connected in series, to the output terminal of the converter. The other selected reference voltage is supplied through another resistor and another switching device, connected in series, to the same output terminal. This arrangement saves space, and enables variations in the output voltage levels to be kept within tolerance by use of resistors with sufficiently high resistance values.
A digital-to-analog converter generates a monotonic sequence of reference voltages and selects an arbitrary pair of reference voltages, adjacent in the monotonic sequence. One of the selected reference voltages is supplied through a resistor and a switching device, connected in series, to the output terminal of the converter. The other selected reference voltage is supplied through another resistor and another switching device, connected in series, to the same output terminal. This arrangement saves space, and enables variations in the output voltage levels to-be kept within tolerance by use of resistors with sufficiently high resistance values.
For example, in order to convert a 6-bit digital signal into an analog signal, a reference voltage generating circuit for generating 17 reference voltages, a first switch circuit having 19 switch pairs each including a MOS transistor for two reference voltages adjacent to each other in accordance with upper four bits, a second switch circuit including a series circuit of 12 MOS transistors and for dividing the difference between the two selected reference voltages using combined ON-resistances into four so as to obtain three intermediate voltages, and a third switch circuit for selectively outputting the lower voltage of the two selected reference voltages or one of the three intermediate voltages in accordance with lower two bits, are provided.