| 摘要 |
PURPOSE: To reduce the occupied surface area of an IC chip by preparing an operational amplifier which functions first as an integrator and then functions as a comparator by switching. CONSTITUTION: An analog input signal is supplied between terminals 10 and 11, and an operational amplifier 25 performs the sample integration of the analog input signal for conversion via a capacitor 31. This integration result is compared with various levels of voltage generated at an output terminal 23 of a stepped signal generator 21. Then MOSFET 38 and 40 perform the switching of functions of the amplifier 25 between an integrator and a comparator. A digital code string is given to a memory register 13 from a code generator 18 in every conversion cycle and stored in the memory 13 when the voltage of a high level is generated at a write control input terminal 17. In such a constitution, the main surface area of a monolithic IC chip can be reduced. |
