| 摘要 |
A first D/A converter generates first and second reference voltages from digital data of upper m bit by using base reference voltages of these reference voltages. A controller outputs a control signal according to which of voltage levels of the first and second reference voltages is higher. An inversion controller outputs digital data of lower n bit as such to a second stage R-2R ladder resistor type D/A converter when judging that the first reference voltage is higher in voltage level than the second reference voltage, and outputs the digital data of the lower n bit to the second stage R-2R ladder resistor type D/A converter by inverting the digital data of the lower n bit when judging that the first reference voltage is lower in voltage level than the second reference voltage. The second stage R-2R ladder resistor type D/A converter uses the digital data inputted from the inversion controller to operate switches for switching the first and second reference voltages, and outputs an analog output voltage value corresponding to digital input data. On this account, it is possible to provide a D/A converter circuit of plural stages capable of easily ensuring uniformity and continuity of the output analog voltage value, and further capable of obtaining high D/A conversion accuracy.
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