Three-transistor image sensor pixel structure expanding dynamic range

The utility model discloses a three-transistor image sensor pixel structure expanding a dynamic range; the three-transistor image sensor pixel structure comprises a photoelectric diode, a reset transistor, a source following transistor, and a selection transistor arranged in a semiconductor substrate; the three-transistor image sensor pixel structure also comprises a transistor capacitor device; a grid electrode of the transistor capacitor device is connected with an anode of the photoelectric diode, and a source drain electrode is connected with an external controllable potential; the transistor capacitor does not work in weak light illumination, and the pixel is high in photosensitivity; the transistor capacitor is added to the photoelectric diode in strong light illumination, and the pixel is reduced in photosensitivity; the three-transistor image sensor pixel structure compresses the strong light illumination pixel photosensitivity, thus expanding pixel dynamic range.