BRIEF DESCRIPTIONS OF THE DRAWINGS
FIG. 1 is a circuit diagram showing the configuration of a first example of the-present invention.
FIG. 2 is a timing diagram showing an example of switch control of the first example of the present invention.
FIG. 3 is a circuit diagram showing a modification of the first example of the present invention.
FIG. 4 is a circuit diagram showing the configuration of a second example of the present invention.
FIG. 5 is a circuit diagram showing the configuration of a third example of the present invention.
FIG. 6 is a timing diagram showing an example of switch control of the third example of the present invention.
FIG. 7 is a circuit diagram of a modification of the third example of the present invention.
FIG. 8 is a circuit diagram of another modification of the third example of the present invention.
FIG. 9 is a circuit diagram showing the configuration of a fourth example of the present invention.
FIGS. 10A, 10B and 10C are schematic views showing examples of a switch noise cancellation circuit used in the fourth example of the present invention.
FIG. 11 is a circuit diagram showing the configuration of a fifth example of the present invention.
FIG. 12 is a circuit diagram showing the configuration of a sixth example of the present invention.
FIG. 13 is a circuit diagram showing the configuration of a conventional OP amplifier.
FIG. 14 is a circuit diagram showing the configuration of a conventional offset cancellation amplifier.
FIG. 15 is a timing diagram showing the method for controlling the offset cancellation amplifier shown in FIG. 14.
FIG. 16 is a circuit diagram showing the configuration of an offset cancellation amplifier described in a first example of Patent Document 1 (JP Patent Kokai Publication No. JP-P2001-292041A).
FIG. 17 is a timing diagram showing the method for controlling the offset cancellation amplifier described in the first example of Patent Document 1 (JP Patent Kokai Publication No. JP-P2001-292041A).
FIG. 18 is a circuit diagram showing the configuration of an offset cancellation amplifier described in a fourth example of Patent Document 1 (JP Patent Kokai Publication No. JP-P2001-292041A).
FIG. 19 is a timing diagram showing the method for controlling the offset cancellation amplifier described in the fourth example of Patent Document 1 (JP Patent Kokai Publication No. JP-P2001-292041A).
FIG. 20 is a circuit diagram showing the configuration of an offset cancellation amplifier described in a first example of Patent Document 2 (JP Patent Kokai Publication No. JP-P2003-168936A).
FIG. 21 is a circuit diagram showing the configuration of an offset cancellation amplifier described in a first example of Patent Document 3 (JP Patent Kokai Publication No. JP-P2005-117547A).
FIG. 22 is a timing diagram showing the method for controlling the offset cancellation amplifier described in the first example of Patent Document 3 (JP Patent Kokai Publication No. JP-P2005-117547A).