Patent ID: 7115963

Claim:
In-pixel circuitry for CMOS image sensors, suitable for APDs operated in the linear mode, characterized by: (a) The first terminal of the APD is connected to a plurality of pass transistors, each connected to a different power supply; (b) The pass transistors have the drain connected to one terminal of the APD, source connected to a power supply, and the gate connected to a n-bit digital decoder; (c) Only one pass transistor is turned on, by the digital decoder at a time; (d) The gain or multiplication factor of the APD is controlled by voltage is applied to the APD, i.e., by which pass transistor is turned on; (e) The second terminal of the APD is connected to the source of the Row-Select Transistor; (f) The second terminal of the APD is also connected to one terminal of a capacitor; (g) The other terminal of the capacitor can be connected to the Ground, or connected to the first terminal of the APD, and thus be connected in series or in parallel, respectively, with the APD.