Patent ID: 11921150
Assignee: AMS INTERNATIONAL AG
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 0:
1. An electric circuit arrangement to determine a level of an excess bias voltage of a single photon avalanche diode, comprising:
a supply terminal to apply a supply potential;
a reference terminal to apply a reference potential;
a bias terminal to apply a bias potential to bias the single photon avalanche diode;
an output terminal to provide an output signal of the single photon avalanche diode, the single photon avalanche diode being connected between the bias terminal and the output terminal;
a controllable switching circuit; and
an evaluation circuit to evaluate the output signal,
wherein the controllable switching circuit is configured to couple the output terminal to the reference terminal in a first operational cycle of the circuit arrangement so that a voltage jump to the level of the excess bias voltage occurs at the output terminal, when a photon hits a photosensitive area of the single photon avalanche diode, and to couple the output terminal to the supply terminal in a subsequent second operational cycle,
wherein the single photon avalanche diode is quenched, when the voltage jump of the output signal to the level of the excess bias voltage is generated at the output terminal, so that a level of the output signal rises with a linear increasing slope,
wherein the evaluation circuit is configured to determine a first time during which the output signal changes at the output terminal from the level of the excess bias voltage to a first threshold value,
wherein the evaluation circuit is configured to determine a second time during which the output signal changes at the output terminal from the first threshold value to a second threshold value being different from the first threshold value, and
wherein the evaluation circuit is configured to determine the level of the excess bias voltage in dependence on the first time and the second time and the first threshold value and the second threshold value.