| 摘要 |
The present invention provides a cyclic AD converter that reduces power consumption by reducing active circuits such as an X2 amplifier or the like and is particularly suitable to implement in an integrated circuit and also an integrator to be used therefor. The cyclic AD converter uses an integrator 11 comprising an operational amplifier 111, a first integration capacitor C1 connected between the input and output terminals of the operational amplifier 111, and a second integration capacitor C2 to be connected selectively between the reference potential source and the input/output terminals of the operational amplifier 111 by way of switches S3 and S4. The integrator 11 operates to sample/hold an analog input signal and also obtain a signal equal to the double of a reference signal from a comparator. As a result, an X2 amplifier required in the conventional converter is replaced by integration capacitors and switches, thereby reducing power consumption and easily implementing into a semiconductor integrated circuit.
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