Patent ID: 8242546

Claim:
A pixel of an image sensor, the pixel comprising: a drain voltage source connected to a drain line, wherein the drain voltage source is connected to provide: a drain readout voltage during a readout of the pixel; and a further drain voltage during a non-addressed state of the pixel; a reset voltage source connected to a reset line, wherein the reset voltage source is connected to provide: a reset pulse and a further reset line voltage during a readout of the pixel; and a forward bias voltage during the non-addressed state of the pixel; a floating diffusion node configured to store a photo-generated charge, a reset charge, and a set charge; a reset diode connected between the floating diffusion node and the reset line to provide the reset charge to the floating diffusion node in response to the reset pulse; a pinned photodiode connected to generate the photo-generated charge; a transfer transistor connected between the pinned photodiode and the floating diffusion node to transfer the photo-generated charge from the pinned photodiode to the floating diffusion node in response to a transfer signal received by the transfer transistor; a junction field effect transistor having a drain connected to the drain line and a gate connected to receive an input signal from the floating diffusion node, wherein the drain readout voltage, the reset pulse, and the further reset line voltage provided by the drain voltage source and the reset voltage source during readout of the pixel have relative voltage levels that drive the junction field effect transistor to active states to provide, at a source of the junction field effect transistor, a first output signal having a voltage level corresponding to the photo-generated charge and a second output signal having a voltage level corresponding to the reset charge; wherein the further drain voltage and the forward bias voltage provided by the drain voltage source and the reset voltage source during the non-addressed state of the pixel have relative voltage levels that forward bias a p-n junction formed between the gate and drain of the junction field effect transistor at a set voltage corresponding to the set charge, and wherein the set voltage has a voltage level that is insufficient to drive the junction field effect transistor to the active states.