Patent ID: 8035542
Filing Date: 2011-10-11
Classification: H03M

Abstract:
1. A digital-to-analog converter comprising: an intermediate potential generating circuit configured to generate a voltage from a first power supply voltage and a second power supply voltage; a reference voltage generating circuit, including one or a plurality of first capacitors coupled in parallel, configured to generate an upper limit reference voltage and a lower limit reference voltage for a reference width which regards the voltage generated in the intermediate potential generating circuit as an intermediate potential; a digital code generating circuit, including second capacitors coupled in parallel and having a capacitance ratio corresponding to a binary weighting value for representing a digital code, configured to convert a change in an analog input signal with respect to the upper limit reference voltage and the lower limit reference voltage that are generated in the reference voltage generating circuit into the digital code, and to output the digital code; and a control circuit configured to control the intermediate potential generating circuit, the reference voltage generating circuit and the digital code generating circuit, in order to achieve a sample and hold of the analog input signal, wherein the control circuit controls the reference voltage generating circuit to charge each first capacitor by supplying thereto the analog input signal using the voltage from the intermediate potential generating circuit as a center voltage during a sample time in which the analog input signal is sampled, and to supply a predetermined constant potential to each charged first capacitor during a hold time in which the digital code is output.