Patent ID: 7327393

Claim:
A variable conversion gain pixel, comprising: an image sensor pixel having a photodiode and a reset transistor for receiving a reset signal to reset the photodiode, a light intensity detector circuit that detects an intensity of incident light and generates a control signal having a level that is based on the detected intensity of incident light, the light intensity detector circuit configured to detect the intensity of incident light separately from incident light detected by the photodiode; and a variable capacitive load in parallel with the photodiode, the variable capacitive load receiving the control signal and varying the variable capacitive load according to the lever of the received control signal; wherein the variable capacitive load includes an OR-gate that receives the control signal and the reset signal, a control transistor connected to the OR-gate far receiving the control signal or the reset signal; a capacitor directly connected to both the control transistor and the reset transistor, wherein the control transistor connects the capacitor in parallel to the photodiode (a) when the control signal generated by the light intensity detector circuit (b) is active, or (b) when the reset signal is active, the control transistor disconnects the capacitor from the photodiode (a) when the control signal generated by the light intensity detector circuit is inactive, and (b) when the reset signal is inactive.