Control of a photosensitive cell

A device for controlling a photosensitive cell comprising:

• a photodiode having a varying voltage according to the lighting, the photodiode being connected to a read node via a MOS transfer transistor, and the read node being connected to a reference voltage via a MOS reset transistor;
• means for reading a voltage representative of the photodiode voltage;
• means for isolating the photodiode from the reference voltage;
• and
• timing means for delaying isolating the photodiode isolation after reading of the voltage representative of the photodiode voltage by the read means;
• wherein
• the means for isolating the photodiode from the reference voltage comprises means for temporarily turning the transfer transistor to an on state while maintaining the reset transistor in an off state.

A photosensitive cell comprising:

• a photodiode configured to have a varying voltage according to lighting;
• a read node connected to the photodiode via a MOS transfer transistor;
• a reference voltage source connected to the read node via a MOS reset transistor;
• first and second MOS read transistors connected serially, the MOS read transistors being configured to read a voltage representative of the photodiode voltage;
• and
• a control circuit configured to send signals to the MOS transfer transistor, the MOS reset transistor, and the second MOS read transistor;
• wherein the control circuit is configured to, during a waiting phase after a read phase, send signals to the transistors to, in order:
• turn the MOS transfer transistor to an on state with the MOS reset transistor being in an off state, turn the MOS transfer transistor to an off state, and turn the MOS reset transistor to an on state, all while the control circuit maintains the second MOS read transistor in an off state.

A method for controlling a photosensitive cell, the method comprising:

• providing at least one timing control to the photosensitive cell;
• and
• thereafter beginning an integration phase;
• wherein providing at least one timing control signal to the photosensitive cell comprises, in order, maintaining a reset control signal and a transfer control signal in a low state from an end of a preceding read cycle, setting the reset control signal to a high state to discharge a read node, returning the reset control signal to the low state, setting the transfer control signal to a high state, and returning the transfer control signal to the low state while the reset control signal remains at the low state.