Spad sensor circuit with biasing circuit
AssigneesThe University Court of the Uniersity of Edinburgh, STMicroelectronics (Research & Development) Limited
InventorsEric Alexander Garner Webster, Robert K. Henderson
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Abstract
A deep SPAD structure uses the substrate as the anode terminal of its multiplication p-n junction. A bias voltage for the SPAD (in excess of the SPAD's breakdown voltage) is coupled to the SPAD's cathode terminal. The bias voltage is generated by a charge pump circuit which is also integrated on the substrate. The charge pump circuit is configured to isolate the bias voltage on the cathode terminal. A triple well CMOS process is used to isolate the transistors of the charge pump circuit from the substrate.
Claims28
A sensor circuit, comprising:
- a single photon avalanche diode (SPAD) configured to receive a bias voltage;
- a charge pump operable to generate said bias voltage from a first voltage and a second voltage, said bias voltage being higher than a breakdown voltage of the SPAD, each of said first voltage and said second voltage being lower than the breakdown voltage of the SPAD;
- wherein said charge pump is operable to isolate the bias voltage on an electrode of the SPAD, thereby biasing said SPAD.
Dependencies are inferred from the claim text.