Patent ID: 8575533

Claim:
A high dynamic range imager circuit, comprising: an image sensor device formed in a first conductive type substrate, including: a photosensor unit for receiving a light signal to generate and accumulate photo-generated charges; a floating diffusion node for storing floating diffusion charges; a transfer gate for coupling the photosensor unit to the floating diffusion node to transfer at least portion of the photo-generated charges to the floating diffusion node as the floating diffusion charges; at least one variable capacitor having a capacitance which is adjustable according to an adjustment voltage; and a dual conversion gain transistor coupled between the floating diffusion node and the variable capacitor, for receiving a conversion gain signal and electrically coupling the floating diffusion node to the variable capacitor in response to the conversion gain signal, for adjusting a gain of reading the floating diffusion charges; and a signal reading circuit coupled to the image sensor device, for converting the floating diffusion charges to a signal which indicates a pixel image sensed by the image sensor device.