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US 9,310,247 B2Granted
Dark current calibration for a photosensitive device
AssigneeSTMicroelectronics (Research & Development) Limited
InventorsJeffrey M. Raynor, Andy Price
Life of this patent
Estimating the term…
Abstract
An imaging circuit includes at least one photosensitive device that provides an output in response to at least one photon and a compensation circuit configured to provide dark current compensation for the output of said photosensitive device. The applied compensation uses temperature information and temperature dependent calibration information.
Claims25
An apparatus, comprising:
- at least one photosensitive device configured to provide an output in response to at least one photon;
- at least one shielded compensation photosensitive device configured in use to provide a dark current value;
- and
- a compensation circuit configured to modify said dark current value of said at least one shielded photosensitive device to provide a temperature compensated dark current value;
- and
- wherein said compensation circuit is further configured to provide dark current compensation for the output of said photosensitive device by processing temperature information and temperature dependent calibration information to compensate for dark current;
- wherein said temperature dependent calibration information is dependent on a calibration measurement of dark currents output from at least one of the photosensitive device and the shielded compensation photosensitive device at a first and a second, different, calibration temperatures.
4 more elements
A method comprising:
- obtaining a dark current value for at least one shielded compensation photosensitive device;
- modifying said dark current value of said at least one shielded photosensitive device to provide a temperature compensated dark current value;
- providing dark current compensation for an output of a photosensitive device by using said dark current value, temperature information and temperature dependent calibration information;
- using said temperature compensated dark current value as a measure of dark current in said output of said at least one photosensitive device;
- and
- calculating said temperature dependent calibration information dependent on a calibration measurement of dark currents output from at least one of the photosensitive device and the shielded compensation photosensitive device at a first and a second, different, calibration temperatures.
3 more elements
Dependencies are inferred from the claim text.