| 摘要 |
PURPOSE:To realize a low-cost A/D conversion having an accuracy of 8 bits or more with no use of the analog switch, the integral output voltage comparing operational amplifier or the like, by introducing the 1-chip computer. CONSTITUTION:The CR integral A/D converting method is realized by using the integral CR circuit 20 and the 1-chip computer 10. Thus the output FFT of the computer 10 is used for an analog switch having a structure of a single pole and single make. And one end of the switch is connected to the substrate, and the voltage to be applied to the other end is limited to VSS or less. At the same time, the MOS logic buffer is used for an analog voltage comparator. And the input voltage to be applied to the voltage comparator is compared with the threshold voltage Vth of a range of each input voltage corresponding to the logic value ''1'' and ''0'' each. Thus the primary integral CR circuit is used with a merit of its simple structure, and as a result an A/D converter can be obtained with a low cost. |
