| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image sensor signal processing circuit for obtaining an optimum signal level in compliance with a signal mean level in AD conversion of a signal from a photoelectric conversion element. <P>SOLUTION: This signal processor is constructed of a variable gain amplifier 1 amplifying a difference with a reference voltage by using a signal output from an image sensor as an input to a reverse input terminal, a peak hold circuit 2 performing sample holding of the maximum value and the minimum value for a periodically varying pixel signal as an output of the variable gain amplifier 1, an integrator 3 receiving differential voltage between the maximum value and the minimum value generated in the peak hold circuit 2 for outputting a low frequency constituent (mean voltage) through a low-pass filter having a predetermined cutoff frequency, and a reference voltage source 5 receiving the output from the integrator 3 and outputting a reference voltage matching the output from the integrator 3 to a non-reverse input terminal in the variable gain amplifier 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
