Low-noise, high dynamic-range image sensor
AssigneeRambus Inc.
InventorsJohn Ladd, Michael Guidash, Craig M. Smith, Thomas Vogelsang, Jay Endsley, Michael T. Ching, James E. Harris
Life of this patent
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Abstract
A sequence of control voltage levels are applied to a control signal line capacitively coupled to a floating diffusion node of a pixel to sequentially adjust a voltage level of the floating diffusion node. A pixel output signal representative of the voltage level of the floating diffusion node is compared with a reference voltage to identify a first control voltage level of the sequence of control voltage levels for which the voltage level of the floating diffusion node exceeds the reference voltage.
Claims21
A method of operation within an integrated-circuit image sensor, the method comprising:
- applying a sequence of control voltage levels to a control signal line capacitively coupled to a floating diffusion node of a pixel to sequentially adjust a voltage level of the floating diffusion node;
- and
- comparing a pixel output signal representative of the voltage level of the floating diffusion node with a reference voltage to identify a first control voltage level of the sequence of control voltage levels for which the voltage level of the floating diffusion node exceeds the reference voltage.
An integrated circuit image sensor comprising:
- a pixel having a photodiode and floating diffusion node switchably interconnected via a transfer gate, and an output circuit to output a signal representative of a voltage level of the floating diffusion node onto a pixel output line;
- a control signal line capacitively coupled to the floating diffusion node;
- a control voltage generator to apply a sequence of control voltage levels to the control signal line to capacitively adjust the voltage level of the floating diffusion node;
- and
- compare circuitry to compare a pixel output signal representative of the voltage level of the floating diffusion node with a reference voltage to identify a first control voltage level of the sequence of control voltage levels for which the voltage level of the floating diffusion node exceeds the reference voltage.
An integrated circuit image sensor comprising:
- a plurality of pixels arranged in rows and columns, each of the pixels having a photodiode switchably interconnected to floating diffusion node via a transfer gate;
- a plurality of column control signal lines, each column control signal line capacitively coupled to the floating diffusion nodes for a respective column of the pixels;
- a control voltage generator to apply a sequence of control voltage levels to the column control signal lines to capacitively adjust respective voltage levels of the floating diffusion nodes of the plurality of pixels;
- and
- a plurality of column compare circuits, each column compare circuit to compare a pixel output signal representative of the voltage level of the floating diffusion node of a pixel within a respective column of the pixels with a reference voltage to identify a first control voltage level of the sequence of control voltage levels for which the voltage level of the floating diffusion node of the pixel exceeds the reference voltage.
Dependencies are inferred from the claim text.