Pixel array capable of performing pipelined global shutter operation including a first and second buffer amplifier

A pixel array capable of pipelined global shutter operation and including an array of pixels, each of the pixels comprising:

• a photo-sensitive element for generating charges in response to incident radiation;
• a sense node;
• a transfer gate, connected between the photo-sensitive element and the sense node, for controlling transfer of charges to the sense node;
• a reset switch connected to the sense node for resetting the sense node to a predetermined voltage;
• a first buffer amplifier having an input connected to the sense node;
• a first sample stage connected to an output of the first buffer amplifier, which is selectively operable to sample a value of the sense node;
• a second sample stage connected in cascade with the first sample stage which is selectively operable to sample a value of the sense node, wherein an output of said first sample stage is connected to an input of said second sample stage;
• and,
• a second buffer amplifier having an input connected to the second sample stage,
• said pixel array further comprising:
• control circuitry arranged to cause the array of pixels to be exposed synchronously, and to read a value stored in the sample stage of one of said pixels in the array for a first exposure period while the photo-sensitive element of said one of the pixels is exposed for a second exposure period.