High dynamic range image sensor with dual-carrier pixel architecture

A camera device, comprising:

• a lens;
• an image sensor comprising:
• a pixel array of a plurality of pixels, wherein individual ones of the pixels include:
• (a) a photodiode that generates electrical current in response to an exposure of light received through the lens,
• (b) a first floating diffusion (FD1) node that collects a first type of charge carrier of the electrical current, and
• (c) a second floating diffusion (FD2) node that collects a second type of charge carrier of the electrical current, wherein the second type of charge carrier is different from the first type of charge carrier;
• a first readout circuitry of the pixel that outputs a first readout value of the FD1 node that is linear with respect to an amount of the electrical current generated in the photodiode;
• and
• a second readout circuitry of the pixel that outputs a second a second readout value of the FD2 node that is logarithmic with respect to the amount of the electrical current generated in the photodiode;
• and
• an image signal processor configured to:
• use the second readout value to generate image data corresponding to the exposure when the first signal exceeds a saturation threshold.

A method, comprising:

• receiving an exposure of light at a pixel array of pixels;
• generating, in response to the exposure, an electrical current in a photodiode of one of the pixels;
• collecting a first type of charge carrier of the electrical current at a first floating diffusion (FD1) node of the pixel;
• collecting a second type of charge carrier of the electrical current at a second floating diffusion (FD2) node of the pixel, wherein the second type of charge carrier is different from the first type of charge carrier;
• outputting, via a first readout circuitry of the pixel, a first readout value of the FD1 node that is linear with respect to an amount of the electrical current generated in the photodiode;
• outputting, via a second readout circuitry of the pixel, a second readout value of the FD2 node that is logarithmic with respect to the amount of the electrical current generated in the photodiode;
• and
• selecting, based on a saturation threshold, a first pixel value determined using the first readout value or a second pixel value determined using the second readout value to generate image data corresponding to the exposure.