Method for measuring ambient light and corresponding integrated device

1. A method for measuring ambient light, the method comprising:

successively synchronizing optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases;

receiving an external control signal representative of the extinction phases of the disruptive light source;

accumulating, in each acquisition phase, photo-generated charges by at least one photosensitive pixel comprising a pinned photodiode;

transferring the accumulated photo-generated charges to an integration node; and

integrating, for each pixel, the transferred charges on the integration node during a series of the successive acquisition phases.

2. The method according to claim 1 , wherein transferring the accumulated photo-generated charges to the integration node comprises lowering an electrostatic potential barrier thereby enabling diffusion of the photo-generated charges to the integration node.

3. The method according to claim 1 , further comprising discharging the at least one pixel of parasitic charges accumulated outside the acquisition phase during a reset at a beginning of each acquisition phase.

4. The method according to claim 3 , wherein the reset comprises lowering an electrostatic potential barrier thereby enabling diffusion of the parasitic charges to a reset node.

5. An integrated ambient light sensing device comprising:

at least one photosensitive pixel comprising a pinned photodiode;

an integrator circuit electrically connected to the photosensitive pixel via an integration node; and

a controller configured to:

successively synchronize optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases;

accumulate, in each acquisition phase, photo-generated charges by the at least one photosensitive pixel; and

transfer the accumulated photo-generated charges to the integration node,

wherein the integration node is configured to integrate the transferred charges during a series of the successive acquisition phases,

wherein the integrator circuit comprises an operational amplifier and a capacitive feedback element,

wherein an output of the operational amplifier is looped back to an inverting input of the operational amplifier via the capacitive feedback element, and

wherein a follower input of the operational amplifier is configured to receive a reference potential from the controller.

6. The device according to claim 5 , wherein each pixel includes a first transfer gate between the pinned photodiode and the integration node, and wherein the controller is configured to control the transfer of the photo-generated charges by generating a potential on the first transfer gate adapted to lower an electrostatic potential barrier and enable diffusion of the photo-generated charges to the integration node.

7. The device according to claim 6 , wherein the first transfer gate is part of a first transistor between a cathode region of the pinned photodiode and a floating diffusion node.

8. The device according to claim 6 , wherein the controller is configured to discharge the at least one pixel of parasitic charges accumulated outside the acquisition phase during a reset at a beginning of each acquisition phase.

9. The device according to claim 6 , wherein each pixel includes a second transfer gate between the pinned photodiode and a reset node, and wherein the controller is configured to control the reset by generating a potential on the second transfer gate adapted to lower an electrostatic potential barrier and enable diffusion of the photo-generated charges to the reset node.

10. The device according to claim 9 , wherein the second transfer gate is part of a second transistor between a cathode region of the pinned photodiode and a floating diffusion node.

11. The device according to claim 5 , further comprising an input configured to receive an external control signal representative of the extinction phases of the disruptive light source.

12. The device according to claim 5 , wherein the at least one pixel comprises a plurality of pixels arranged in rows and columns.

13. A system comprising:

a light-emitting display screen;

the device according to claim 6 ; and

a camera,

wherein the light-emitting display screen is the disruptive light source.

14. A method for measuring ambient light, the method comprising:

successively synchronizing optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases;

accumulating, in each acquisition phase, photo-generated charges by at least one photosensitive pixel comprising a pinned photodiode;

transferring the accumulated photo-generated charges to an integration node;

integrating, for each pixel, the transferred charges on the integration node during a series of the successive acquisition phases; and

discharging the at least one pixel of parasitic charges accumulated outside the acquisition phase during a reset at a beginning of each acquisition phase,

wherein the reset comprises lowering an electrostatic potential barrier thereby enabling diffusion of the parasitic charges to a reset node.

15. The method according to claim 14 , wherein transferring the accumulated photo-generated charges to the integration node comprises lowering an electrostatic potential barrier thereby enabling diffusion of the photo-generated charges to the integration node.

16. An integrated ambient light sensing device comprising:

at least one photosensitive pixel comprising a pinned photodiode;

an input configured to receive an external control signal representative of an extinction phases of a disruptive light source;

an integrator circuit electrically connected to the photosensitive pixel via an integration node; and

a controller configured to:

successively synchronize optical signal acquisition phases with extinction the phases of the disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases;

accumulate, in each acquisition phase, photo-generated charges by the at least one photosensitive pixel; and

transfer the accumulated photo-generated charges to the integration node,

wherein the integration node is configured to integrate the transferred charges during a series of the successive acquisition phases.

17. An integrated ambient light sensing device comprising:

at least one photosensitive pixel comprising a pinned photodiode;

an integrator circuit electrically connected to the photosensitive pixel via an integration node; and

a controller configured to:

successively synchronize optical signal acquisition phases with extinction phases of a disruptive light source, wherein the disruptive light source periodically provides illumination phases and the extinction phases;

accumulate, in each acquisition phase, photo-generated charges by the at least one photosensitive pixel; and

transfer the accumulated photo-generated charges to the integration node,

wherein the integration node is configured to integrate the transferred charges during a series of the successive acquisition phases,

wherein each pixel includes a first transfer gate between the pinned photodiode and the integration node, the controller being configured to control the transfer of the photo-generated charges by generating a potential on the first transfer gate adapted to lower an electrostatic potential barrier and enable diffusion of the photo-generated charges to the integration node, and

wherein each pixel includes a second transfer gate between the pinned photodiode and a reset node, the controller being configured to control the reset by generating a potential on the second transfer gate adapted to lower an electrostatic potential barrier and enable diffusion of the photo-generated charges to the reset node.

18. The device according to claim 17 , wherein the second transfer gate is part of a second transistor between a cathode region of the pinned photodiode and a floating diffusion node.