Patent ID: 7714264

Claim:
A semiconductor integrated circuit device comprising: a correlated dual sampling circuit for sampling and holding a signal corresponding to a black level of a feed through part of a pixel signal generated by an image sensor device and generating an output signal corresponding to a differential signal with respect to a signal part of the pixel signal; a variable gain amplifier circuit for amplifying the output signal of the correlated dual sampling circuit; an A/D converter circuit for receiving an amplified signal from the variable gain amplifier circuit; and a D/A converter circuit for converting a received feedback signal formed with an output signal of the A/D converter circuit and a clamp signal into an analog signal and providing the analog signal as feedback to the variable gain amplifier circuit or the correlated dual sampling circuit, wherein the D/A converter circuit includes a plurality of first-conductivity-type MOSFETs as first current sources for feeding respective currents having binary weights corresponding to multiple-bit digital signals, a plurality of first-conductivity-type first differential MOSFETs which receive the multiple-bit digital signals respectively, a first differential amplifier circuit in which a predetermined first bias voltage is supplied to a noninverting input terminal of the first differential amplifier circuit and an inverting input terminal of the first differential amplifier circuit is connected to a first analog current output node to which the drains are connected on of one of the sides of the first differential MOSFETs, a voltage of said first analog output node being maintained substantially equal to said first bias voltage, and a resistive element which is provided between the inverting input terminal and an output terminal of the first differential amplifier circuit, and wherein the first differential amplifier circuit generates a converted analog output voltage at the output terminal.