Bulk charged modulated device (BCMD) image sensors with increased dynamic range
AssigneeTexas Instruments Incorporated
InventorsAlan N. Cooper, William P. McCracken, Jaroslav Hynecek
Life of this patent
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Abstract
An image array with improved dynamic range has at least one photosite, at least one column sense line and at least one column clamp transistor. A source of the photosite is coupled to the column sense line. A source of the column clamp transistor is coupled to the photosite source. A drain of the column clamp transistor is coupled to a drain of the photosite. A gate of the column clamp transistor is provided for application of a .phi..sub.cc signal. The .phi..sub.cc signal is coupled through a capacitance to the column sense line.
Claims1
An image array having at least one photosite transistor, at least one column sense line and at least one column clamp transistor, wherein:
- a source of said photosite transistor is coupled to said column sense line;
- a source of said column clamp transistor is coupled to said photosite source;
- a drain of said column clamp transistor is coupled to a drain of said photosite transistor;
- a clocked voltage is applied to a gate of said column clamp transistor;
- and
- a variable current is coupled to said column sense line, the variable current is decreased when the clocked voltage is increased.
Dependencies are inferred from the claim text.