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, according to digital input. A switching network
charges a capacitor according to the difference between the two selected
reference voltages, then connects another capacitor to the first
capacitor to generate a voltage intermediate between the two selected
reference voltages by redistributing charge between the capacitors. The
switching network also selects one of the selected reference voltages or
the intermediate voltage as the analog output voltage. This conversion
scheme saves space with little or no increase in current consumption.