FLOATING DIFFUSION RESET LEVEL BOOST IN PIXEL CELL

摘要

A reset level in a pixel cell is boosted by switching ON a reset transistor of the pixel cell to charge the floating diffusion to a first reset level during a reset operation. A select transistor is switched from OFF to ON during the floating diffusion reset operation to discharge an output terminal of an amplifier transistor. The reset transistor is switched OFF after the output terminal of the amplifier transistor has been discharged in response to the switching ON of the select transistor. The output terminal of the amplifier transistor charges to a static level after being discharged. The floating diffusion coupled to the input terminal of the amplifier transistor follows the output terminal of the amplifier transistor across an amplifier capacitance coupled between the input terminal and the output terminal of the amplifier transistor to boost the reset level of the floating diffusion.

主权项

1. A method for boosting a reset level in a pixel cell, comprising:
switching ON a reset transistor coupled between a reset voltage and a floating diffusion of the pixel cell to charge the floating diffusion to a first reset level during a reset operation of the floating diffusion, wherein the floating diffusion is coupled to an input terminal of an amplifier transistor; switching from OFF to ON a select transistor coupled between an output terminal of the amplifier transistor and an output bitline of the pixel cell during the floating diffusion reset operation to initially discharge the output terminal of the amplifier transistor through the select transistor; and switching OFF the reset transistor after the output terminal of the amplifier transistor has been initially discharged in response to the switching ON of the select transistor during the floating diffusion reset operation, wherein the output terminal of the amplifier transistor charges to a static level after being initially discharged in response to the switching ON of the select transistor during the reset operation of the floating diffusion, and wherein the floating diffusion coupled to the input terminal of the amplifier transistor follows the output terminal of the amplifier transistor across an amplifier capacitance coupled between the input terminal and the output terminal of the amplifier transistor to boost the reset level of the floating diffusion from the first reset level to a second reset level as the output terminal of the amplifier transistor charges to the static level.