SOLID-STATE IMAGING APPARATUS AND SEMICONDUCTOR DEVICE

摘要

The present invention provides a small-sized inexpensive solid-state imaging apparatus. A D/A converter included in a successive comparison type A/D converter of the solid-state imaging apparatus includes a multiplexer which selects any of reference voltages VR0 to VR16 and sets it as an analog reference signal when coarse A/D conversion is performed, and which selects reference voltages VR (n−1) to VR (n+2) of the reference voltages VR0 to VR16 when fine A/C conversion is performed, and a capacitor array which generates an analog reference signal, based on the reference voltages VR (n−1) to VR (n+2) when the fine A/D conversion is performed. It is thus possible to reduce settling errors in reference voltage without using redundant capacitors.

主权项

1. A solid-state imaging apparatus comprising:
pixel circuits each of which outputs an analog pixel signal of a voltage corresponding to an incident light quality; a reference voltage generating circuit which generates first through Nth reference voltages; and successive comparison type A/D converters each of which performs an A/D conversion of the analog pixel signal, based on the first through Nth reference voltages; wherein the A/D conversion includes a coarse A/D conversion for performing a first normal comparison operation and a fine A/D conversion for performing a second normal comparison operation and a redundant comparison operation, wherein the successive comparison type A/D converter includes:
a D/A converter which converts a digital reference signal to an analog reference signal;a comparator which compares the magnitudes of the analog pixel signal and the analog reference signal and outputs a result of comparison therefrom; anda successive approximation register which is operated based on the result of comparison by the comparator to generate the digital reference signal in such a manner that the analog reference signal approximates the analog pixel signal, and wherein the D/A converter includes:
a multiplexer which, when the coarse A/D conversion is performed, selects any of the first through Nth reference voltages and applies the selected reference voltage to the comparator as the analog reference signal and which, when the fine A/D conversion is performed, selects (n−1)th through (n+2)th reference voltages of the first through Nth reference voltages; and a capacitor array which, when the fine A/D conversion is performed, generates the analog reference signal, based on the (n−1)th through (n+2) the reference voltages selected by the multiplexer.