| 摘要 |
PURPOSE:To obtain a switched capacitor type A/D converter where offset of a comparator does not give effect on the accuracy by providing plural switched capacitors, an inverse amplifier and a control circuit. CONSTITUTION:Switches S21, S23 connected to an input signal terminal 21, a switch S22 connected to a reference voltage terminal 22, a switch S24 connected to a common terminal, a capacitor C21 connected to the other end of the switches S21, S22, a capacitor C22 connected to the other end of the switches S23, S24, and the inverse amplifier whose input is connected to the other end of the capacitors C21, C22 are provided to this A/D converter. Further, said A/D converter is provided with a switch S25 whose one end is connected to an output terminal of the amplifier 23 and whose other end is connected to the other end of the capacitor C21, a switch S26 whose one end is connected to the output terminal 23 of the amplifier 23 and whose other end is connected to the input terminal, a switch S27 whose one end is connected to a feedback input terminal 25 and whose other end is connected to the capacitor C22, and a control circuit 27 inputting a comparison output Vc and an external clock and generating a control signal to the switches S21-S27. |
