SOLID-STATE IMAGE SENSING DEVICE AND ITS DRIVING METHOD

摘要

PROBLEM TO BE SOLVED: To collect a logarithmic characteristic section in the operating range of a post-stage circuit even when a gain for a reading circuit at a post stage is changed, when a dynamic range is expanded by using photoelectric-conversion characteristics (logarithmic characteristics) after the saturation of a photodiode. SOLUTION: A sequencer 8 extracts an off-potential register value corresponding to a gain value input from a gain register 7; and sets the off-potential register value to an off-potential register 9 from a relational table making the off-potential register value correspond to the gain value so that the broken-point potential of the photoelectric-conversion characteristics of the photodiode 30 is collected in the operating range of an AGC circuit 6 when the AGC circuit 6 is operated at the gain value. A variable voltage source 10 applies a voltage value corresponding to the off-potential register value at the control end of a driving buffer 46 through a buffer amplifier 11. The driving buffer 46 changes the potential of a level signal on the side driving a charge-transfer transistor 32 to an off-operation state. COPYRIGHT: (C)2007,JPO&INPIT