| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable gain analog-to-digital converter which can be adapted or applied according to an illumination level of each of pixels of a photosensitive cell. SOLUTION: A variable analog-to-digital converting apparatus 1 for the image sensor comprises at least one first N-bit nonlinear coarse converter 21 which receives a pixel voltage signal (Vpix), so that the apparatus feeds a binary word of N+M bits continuously relating to a voltage of a pixel, and at least one second M-bit linear fine converter 22 which is connected to the first converter 21. The first converter 21 comprises a comparator means for comparing a voltage level of the pixel with voltage thresholds (V0-V4) for determining a voltage range within a voltage dynamic range of the sensor. The second converter comprises a converting adapting means for converting the voltage pixel signal into bits equal to or less than M in response to an N-bit binary word from the first converter. COPYRIGHT: (C)2005,JPO&NCIPI
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