| 摘要 |
PROBLEM TO BE SOLVED: To accelerate AD conversion processing in a CMOS (Complementary Metal-oxide Semiconductor) image sensor adopting a single slope integrated AD conversion system. SOLUTION: Both the inclination control of a reference signal and the frequency division speed control of a counter are used. For example, the inclination of a reference signal Vslop is doubled with respect to the preceding inclination at a point R (t21), and the frequency division speed of the counter is doubled. Compared with processing with the inclination of the reference signal fixed as it is, the period of time for comparison processing in AD conversion processing can be shortened more as the signal becomes larger, and the AD conversion processing becomes faster as the signal becomes larger. By correcting AD conversion gain decrease involved in an increase in an inclination of the reference signal from the aspect of a frequency division speed of the counter, digital data with signal components reflecting faithfully can be acquired without performing correction operation. COPYRIGHT: (C)2008,JPO&INPIT
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