| 摘要 |
A programmable voltage source produces a set of output reference voltages having levels determined by a sequence of input data values, each input data value corresponding to a separate one of the reference voltages. The voltage source includes a charging current generator for generating a charging current and a set of sample and hold circuits, each corresponding to a separate one of the data values, each for producing a separate one of the output reference voltages. The charging current generator receives each data value in succession and supplies a charging current to the corresponding sample and hold circuit and that sample and hold circuit adjusts its output reference voltage by integrating the charging current. The charging current generator monitors the output reference voltage produced by that sample and hold circuit and sets the charging current to a level proportional to a difference between the reference voltage level and a level indicated by the input data. The reference voltage output of the sample and hold circuit therefore stabilizes at the level indicated by the input data. |
