Method for reading a pixel with charge/voltage dual conversion gain and corresponding system

A system, comprising:

• a pixel having a photodiode configured to store charges and a reading node, wherein the pixel is placeable in response to a control signal in either a high conversion gain mode or a low conversion gain mode;
• and
• a circuit configured to read the pixel with charge/voltage conversion dual conversion gain, the circuit including a processing circuit configured to deliver said control signal and to implement a reading operation that successively includes:
• a) a reset of the reading node of the pixel placed in the low conversion gain mode, followed by a first transition of the mode control signal to place the pixel in the high conversion gain mode;
• b) with the pixel in the high conversion gain mode, a first charge transfer from the photodiode to the reading node with a high conversion gain;
• and
• c) a second transition of the control signal to place the pixel in the low conversion gain mode, followed by a second charge transfer from the photodiode to the reading node with a low conversion gain, followed by a third transition of the control signal, opposite to the second transition, to place the pixel back in the high conversion gain mode.

A sensor, including:

• a pixel matrix organized in rows and columns;
• each pixel of the pixel matrix having a photodiode configured to store charges and a reading node, wherein the pixel is placeable in response to a control signal in either a high conversion gain mode or a low conversion gain mode;
• and
• a reading device respectively connected to each column, said reading device comprising a circuit configured to read the pixel with charge/voltage conversion dual conversion gain, the circuit including a processing circuit configured to deliver said control signal and to implement a reading operation that successively includes:
• a) a reset of the reading node of the pixel placed in the low conversion gain mode, followed by a first transition of the mode control signal to place the pixel in the high conversion gain mode;
• b) with the pixel in the high conversion gain mode, a first charge transfer from the photodiode to the reading node with a high conversion gain;
• and
• c) a second transition of the control signal to place the pixel in the low conversion gain mode, followed by a second charge transfer from the photodiode to the reading node with a low conversion gain, followed by a third transition of the control signal, opposite to the second transition, to place the pixel back in the high conversion gain mode.