Spad array with pixel-level bias control
First Claim
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1. A sensing device, comprising:
- a global bias generator, which is configured to generate a global bias voltage;
an array of sensing elements, each sensing element coupled to receive the global bias voltage and comprising;
a photodiode, comprising a p-n junction; and
a local biasing circuit, coupled in series with the photodiode and the global bias voltage and configured to apply an excess bias voltage across the p-n junction so as to reverse-bias the p-n junction at a total bias voltage that is a sum of the global bias voltage and the excess bias voltage and is greater than a breakdown voltage of the p-n junction by a margin sufficient so that a single photon incident on the p-n junction triggers an avalanche pulse output from the sensing element; and
a bias control circuit, which is coupled to set the excess bias voltage in different ones of the sensing elements to different, respective values.
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Abstract
A sensing device includes an array of sensing elements. Each sensing element includes a photodiode, including a p-n junction, and a local biasing circuit, coupled to reverse-bias the p-n junction at a bias voltage greater than a breakdown voltage of the p-n junction by a margin sufficient so that a single photon incident on the p-n junction triggers an avalanche pulse output from the sensing element. A bias control circuit is coupled to set the bias voltage in different ones of the sensing elements to different, respective values that are greater than the breakdown voltage.
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Citations
18 Claims
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1. A sensing device, comprising:
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a global bias generator, which is configured to generate a global bias voltage; an array of sensing elements, each sensing element coupled to receive the global bias voltage and comprising; a photodiode, comprising a p-n junction; and a local biasing circuit, coupled in series with the photodiode and the global bias voltage and configured to apply an excess bias voltage across the p-n junction so as to reverse-bias the p-n junction at a total bias voltage that is a sum of the global bias voltage and the excess bias voltage and is greater than a breakdown voltage of the p-n junction by a margin sufficient so that a single photon incident on the p-n junction triggers an avalanche pulse output from the sensing element; and a bias control circuit, which is coupled to set the excess bias voltage in different ones of the sensing elements to different, respective values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for sensing, comprising:
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generating a global bias voltage; providing an array of sensing elements, each sensing element coupled to receive the global bias voltage and comprising a photodiode, comprising a p-n junction, and a local biasing circuit, coupled in series with the photodiode and the global bias voltage and configured to apply an excess bias voltage across the p-n junction so as to reverse-bias the p-n junction at a total bias voltage that is a sum of the global bias voltage and the excess bias voltage and is greater than a breakdown voltage of the p-n junction by a margin sufficient so that a single photon incident on the p-n junction triggers an avalanche pulse output from the sensing element; and setting the excess bias voltage in different ones of the sensing elements to different, respective values. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification