| 摘要 |
The invention concerns a random access CMOS image sensor with an integrated low-pass filter. Said sensor comprises cells (Pixel) each having a photodiode (D) consisting of a junction (PN) in the substrate (P), a precharge PMOS transistor (T1), another PMOS sampling transistor (T2), an NMOS reader transistor (T3) and an NMOS selection transistor (T4). Depending on different arrangements between the precharge (Prec) and sample (Sample) signals on the gates of transistors T2 and T4, said sensor can have either a simple sensing mode, or a time-based low-pass filtering sensing mode. Said sensor further comprises an analog storage unit, in each cell (Pixel) consisting of a gate capacitor of an NMOS transistor (T3) and a PMOS sampling transistor (T2) for storing the sensed signal. The PMOS sampling transistor (T2) is housed in a casing (N) (Nwell) and protected against light by at least a metal coating above. Said sensor further comprises two address decoders X and Y for synchronously reading a selected cell. A simple application of the addresses X and Y enables to read the corresponding pixel among the sensor set of pixels without requiring any clock signal.
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