Digital pixel sensor with reduced noise

摘要

An apparatus and method for forming a digital image are disclosed. The apparatus includes a plurality of pixel sensors and a controller. Each sensor includes a photodiode, a floating diffusion node that can be selectively connected to said photodiode or a reset voltage, and an analog-to-digital converter (ADC) connected to the floating diffusion node, the ADC converting a voltage on the floating diffusion node to a digital value. Each pixel sensor also includes an output circuit that connects the ADC to a bus. The apparatus also includes a controller that causes the ADCs to operate in parallel to convert the voltages on the floating diffusion nodes to the digital values in a time that is less than the time needed for the floating diffusion node to acquire ten electron equivalents of noise. The optional apparatus includes circuitry that allows correlated double sampling to be performed in each sensor.

主权项

1. An apparatus comprising:
a plurality of pixel sensors, each pixel sensor comprising: a photodiode, a transfer gate that connects said photodiode to a floating diffusion node that accumulates noise when said floating diffusion node is floating, said floating diffusion node being connected to said photodiode in response to a transfer gate signal; a reset gate that connects said floating diffusion node to a reset voltage in response to a reset gate signal; an analog-to-digital converter (ADC) connected to said floating diffusion node, said ADC converting a voltage on said floating diffusion node to a digital value; an output circuit that connects said ADC to a bit bus; and a controller that causes said ADCs to operate in parallel to convert said voltages on said floating diffusion nodes to said digital values in a time that is less than the time needed for said floating diffusion node to acquire ten electron equivalents of noise.