Patent ID: 8847136

Claim:
An image sensing device comprising: an array of light sensing elements, respective ones of the light sensing elements comprising a photodiode and a plurality of control transistors, the plurality of control transistors comprising at least a transfer gate transistor, a reset transistor, and a source follower transistor, the transfer gate transistor having a drain terminal being a floating diffusion node and a source terminal coupled to the photodiode, the reset transistor having a drain terminal coupled to a reset level voltage and a source terminal coupled to the floating diffusion node, and the source follower transistor having a gate terminal coupled to the floating diffusion node and a drain terminal connected to a positive power supply voltage, wherein respective ones of the light sensing elements are configured to generate an output pixel voltage indicative of an intensity level of light impinging on the photodiode, and the plurality of control transistors are configured to control reset, light integration, charge transfer and data read operations of respective ones of the light sensing elements; and wherein respective ones of the light sensing elements are configured to selectively operate in a first operation mode for high conversion gain or a second operation mode for low conversion gain, the reset level voltage being the positive power supply voltage in the first operation mode and the reset level voltage being a partial reset voltage having a voltage value slightly less than a pinning voltage of the photodiode in the second operation mode; and the positive power supply voltage is the same in both the first and second operation modes.